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6 Preoperative Evaluation inColorectal Patients
97
ease, or cerebrovascular disease [10, 11]. Accordingly,
implementation of these ACC/AHA guidelines in a preoperative clinic led to a reduction in exercise stress testing, lower
hospital length of stay, increased beta-blocker therapy, and
improved preoperative testing appropriateness while preserving a low cardiac complication rate [12].
Chest X-Ray
The American College of Physicians recommends obtaining
chest X-ray (CXR) for patients with known cardiopulmonary
disease, as well as all patients 50years or older who require
major abdominal surgery [13]. The American Heart
Association also recommends CXR (posterior–anterior and
lateral views) on obese patients with BMI ≥40 [14]. Despite
these recommendations, CXR are low yield in identifying
clinically signicant abnormalities that necessitate or alter
management [15].
Advanced Diagnostic Imaging
Depending on the underlying diagnosis, additional advanced
diagnostic imaging may be either benecial for operative
planning or necessary for appropriate staging. In the setting
of Crohn’s disease, magnetic resonance enterography (MR
enterography) is a valuable adjunct to evaluate the small and
large intestine and determine if there is any other disease that
may require attention intraoperatively. MR enterography has
supplanted uoroscopy or small bowel follow-through
examinations. The benet of MR enterography is its ability
to provide objective functional assessment of motility as
well as differentiation from active inammatory disease vs.
chronic brotic disease of the bowel wall, the former being
more amenable to medical therapy and the latter often necessitating surgical intervention. Similarly, MRI of the pelvis is
now the standard imaging modality for rectal cancer and is
required for appropriate locoregional staging.
In the setting of colon or rectal cancer, CT of the chest,
abdomen, and pelvis is recommended for appropriate distant
metastatic disease evaluation. In addition, CT scan may benet operative planning and determining if other organs are
involved in the disease process and may require en-bloc
resection (i.e., duodenum, pancreas, ureters) secondary to
invasive T4 disease. Similarly, for diverticulitis, CT scanning
may help with preoperative planning and adjacent structure
inammation. Furthermore, CT may be benecial and is the
preferred method in evaluation for abscess and stula.
Table 6.1 Surgical risk estimates according to the type of surgery or
intervention [160]
Low risk: <1%
Supercial
surgery
Breast Carotid
Dental Peripheral arterial
Endocrine:
thyroid
Eye Head and neck
Reconstructive Neurological or
Carotid
asymptomatic
(CEA or CAS)
Gynecology:
minor
Orthopedic: minor
(meniscectomy)
Urologic: minor
(transurethral
resection of the
prostate)
Intermediate risk:
1–5% High risk: >5%
Intraperitoneal:
splenectomy, hiatal
hernia repair,
cholecystectomy
symptomatic (CEA
or CAS)
angioplasty
Endovascular
aneurysm repair
injury
orthopedic: major
(hip and spine
injury)
Urologic or
gynecological:
major
Renal transplant Total cystectomy
Intra-thoracic:
non-major
Aortic and major
vascular surgeries
Open lower limb
revascularization or
amputation or
thromboembolecomy
Duodeno-pancreatic
surgery
Liver resection, bile
duct injury
Esophagectomy
Repair of perforated
bowel
Adrenal resection
Pneumonectomy
Pulmonary or liver
transplant
tial for adverse perioperative cardiac events. In general, surgical risk groups are based on the type of surgery and dened
as “low,” “intermediate,” and “high-risk,” with 30-day cardiac event rates (MI and death) of <1%, 1–5%, and >5%,
respectively [16]. The highest risk noncardiac procedures
include vascular, thoracic, and transplant procedures [17].
All abdominal procedures involving the colon and rectum
are included within the “intermediate” risk group (at a minimum) with perforated viscera classied as “high risk”
(Table6.1) [18]. Laparoscopic cases are treated similarly to
open cases regarding cardiac risk. Patients presenting in the
emergency setting should not be delayed for further cardiac
workup such that the benet of a detailed cardiac assessment
is overshadowed by the risk of delaying care of an acute
intra-abdominal pathology such as perforated viscus and
sepsis.
Cardiac Evaluation
Assessment ofCardiac Risk
Appropriate preoperative assessment is essential to identify
patients who may be at increased risk. Further preoperative
investigation and intervention will help minimize the poten-
Initial Workup
The most common postoperative cardiac events include
myocardial infarction, heart failure, arrhythmia, and cardiac
arrest. The rst step in determining whether a patient is at
high risk is to obtain a detailed history and physical during
the ofce consultation. Symptoms requiring further investi-
98
R. G. Landmann and T. D. Francone
gation include but are not limited to palpitations, chest pain,
syncope, dyspnea, and orthopnea. Not only is a history of
cardiac disease important (including valvular or ischemic
heart disease, cardiomyopathy, and arrhythmia), but also a
history of diabetes, renal impairment, peripheral artery disease, and cerebrovascular disease can be extremely relevant
in assessing risk due to their association with coronary artery
disease [19]. Clinical cardiac risk factors include angina,
prior MI, heart failure, stroke/transient ischemic attack
(TIA), renal dysfunction, and Insulin-Dependent Diabetes
Mellitus (IDDM). Additionally, exercise tolerance, ambulatory EKG changes, echocardiographic changes demonstrating prior MI, valvular disease or left ventricular diastolic
dysfunction, and positive stress test have also been associated with increased risk of perioperative cardiac event [20].
Of specic importance is an assessment of a patient’s
functional capacity. It is estimated based on patient daily
activity or measured with exercise testing. As a reference, 1
MET is an expended metabolic equivalent at rest, 4 METs
are equivalent to climbing 2 ights of stairs, and 10 METs
represent strenuous sports activities. Patients with greater
than 4 METs do not require further cardiac workup, regardless of risk factors. Patients with less than 4 METs are considered to have poor functional capacity in which current
guidelines recommend to undergo further cardiac evaluation
and risk-benet analysis (Table6.2) [16, 21]. A recent study
of 12,846 patients undergoing elective resection for colorectal malignancy demonstrated signicantly lowered postoperative complications and mortality in patients who had
preoperative leisure-time physical activity with MET ≥12
compared to those with an MET <12 (12.1% vs. 14.9%,
p = 0.006 and 0.3% vs. 0.8%, p = 0.009, respectively).
Indeed, this increased activity level also was signicantly
correlated with an increased disease-free and overall survival
in these patients undergoing colorectal cancer surgery
(62.8% vs. 55.7%, −< 0.0001 and 66.7% vs. 58.7%,
p<0.0001) [22]. There are several validated models that can
be used by the clinician to predict the risk of peri-cardiac
adverse events. The simplest of these models is the Revised
Goldman Cardiac Risk Index (RCRI) (Table6.3) [5]. Other
user-friendly models including the American College of
Table 6.2 Cardiac risk metabolic equivalents are used to measure
functional capacity and are often utilized for preoperative risk assessment in surgical candidates of all ages
Excellent (>7 METs)
Playing squash Cycling Vacuuming
Jogging– pace of
10minutes/mile
Scrubbing oors Walking 4mph Walking 2mph
Singles tennis match Gardening Writing
One MET=oxygen consumption of a 70kg, 40-year-old at rest
Adapted from ACC/AHA guidelines
Moderate (4–7
METs) Poor (<4 METs)
Playing golf (no
cart)
Activities of daily
living
Table 6.3 Goldman Cardiac Risk Index is a tool used to estimate a
patient’s risk of perioperative cardiac complications [38]
Points
History
MI within 6months 10
Age >70years 5
Physical examination
S3 or jugular vein depression 11
Signicant aortic stenosis 3
Electrocardiogram
Rhythm other than sinus or sinus rhythm with or
without atrial premature complexes on last ECG
Five premature ventricular complexes/min any time
before surgery
Other factors
Poor general medical status 3
Intraperitoneal intrathoracic or aortic operation 3
Emergency operation 4
Total points 53
Probability of life-threatening complications based on risk index
points
Probability of
None/minor
complications
Class Points
I 0–5 99 0.7 0.2
II 6–12 93 5 2
III 13–25 86 11 2
IV >26 22 22 56
(%)
life-threatening
complications
(%)
7
7
Cardiac
death
(%)
Surgeons National Surgical Quality Improvement Program
(ACS–NSQIP) risk calculator require more input variables
but will also provide procedure-specic quantication of
other noncardiac risk factors [23].
Additional Testing
Further testing has been recommended for patients with a
greater than 1% risk of perioperative death from cardiac disease as these patients are more likely to have a known history
of recent myocardial infarction, unstable angina, heart failure, valvular disease, or arrhythmias [11]. These patients
should be evaluated by their cardiologist. Additionally, anything less than 4 METs is considered poor functional capacity but is not strongly associated with worsened cardiac
outcomes in abdominal surgery. Current guidelines recommend patients with poor functional capacity to undergo further cardiac evaluation and risk-benet analysis [16, 21].
Figure6.1 describes a generalized algorithm for determining
the need for further workup in elective noncardiac colorectal
surgery patients.
Further testing may include echocardiography, stress test
(exercise or pharmacologic), 24-hour ambulatory monitoring, and cardiac catheterization. Patients undergoing medium
risk surgery (i.e., abdominal surgery) without risk factors
should be considered for an EKG evaluation per recent ACC/
6 Preoperative Evaluation inColorectal Patients
99
Fig. 6.1 Algorithm to
determine the need for further
cardiac workup in noncardiac
patients undergoing colon and
rectal surgeries
Examples:
RCRI
NSQIP Calcular
Emergent Surgery
No
Acute Coronary Syndrome
No
Calculate combined
clinical and surgical sisk
High >%
Estimate functional status
<4 METs or
unknown
Will further testing impact
decision-making or
perioperative care?
Ye s
Ye s
Low <1%
>4–10 METs
No
Ye s
Surgery
Follow ACS Guidelines
Surgery
Pharmacological stress testing
AHA guidelines. EKG is required for patients with presence
of cardiac risk factors prior to any surgical intervention.
Echocardiography is not required for patients free of cardiac
symptoms but should be considered in patients undergoing
high-risk surgery or who have cardiac risk factors [20, 21].
Image stress testing should be performed in patients with
multiple risk factors undergoing medium-to-high risk surgery and poor or unknown functional capacity if it will
change management.
Patients with unstable symptoms, a high-risk/abnormal
stress test, concern for severe CAD (with or without left ventricle dysfunction), or those refractory to medical therapy,
should undergo coronary angiography. Revascularization is
indicated only when dictated by other guidelines; however,
routine coronary revascularization should not be performed
exclusively to reduce perioperative risks [11]. Interestingly,
there is minimal evidence to suggest that preoperative revascularization reduces risk in non-cardiac surgery. Instead of
cardiac catheterization, beta-blockade and statins pre- and
perioperatively are strongly recommended [20].
Preoperative Optimization andMedical Therapy
The need for medical optimization prior to surgery is dictated by the ndings of the cardiac evaluation. Patients on
longstanding beta-blockers should be continued with their
medical regimens. However, beta-blockers should not be initiated de novo in the preoperative setting. Multiple studies
and meta-analyses have documented a signicant increase in
the risk of nonfatal stroke and myocardial ischemic events
and hypertensive-related morbidity and mortality when betablockers are started within 24hours prior to surgery [24, 25].
Antihypertension medications can be adjusted to avoid perioperative hypotension targeting a systolic blood pressure of
116–130mmHg at a heart rate of 60–70bpm. When diagnosed, new dysrhythmias can be controlled with antiarrhythmic agents. Decompensated heart failure increases
perioperative risk and this risk may be mitigated by treatment with ACE inhibitors, aldosterone antagonist, and
digoxin for at least 1week preoperatively [26]. Patients may
continue to take statins previously prescribed. Preoperative
initiation of statins is reasonable in patients undergoing vascular surgery; however, there is no data to support starting
statins preemptively in the setting of colorectal surgery [25].
Preoperative Anticoagulation
In recent years, several novel oral anticoagulants have
become commercially available and are widely used in
patients with atrial brillation or history of stroke in addition
to placement of coronary or endovascular stents. Table6.4
summarizes the more commonly seen anticoagulants and
recommendations for perioperative management. For all
patients taking anticoagulant therapy who are scheduled for
a procedure, it is important to carefully review the medical
history, medication list, and laboratory test results to identify
100
Table 6.4 Description and perioperative recommendations for common oral anticoagulant agents
Temporary interruption
recommendations (when to stop/
Agent Pathophysiology When to interrupt
Warfarin
(Coumadin)
DOCA
1. Apixaban
2. Dabigatran
3. Edoxaban
4. Rivaroxaban
Clopidrogel Platelet receptor PY12
Heparin
(unfractionated)
Vitamin K antagonist
Inhibits the synthesis of
vitamin K-dependent
clotting factors II, VII, IX,
and X as well as the
anticoagulant proteins C
and S
Half-life of approximately
36–42hours
Factor Xa inhibitor
anticoagulant agents
Rapid onset of action
(1–3hours)
Dose must be decreased
for Cr ≥5, age >80 and
body weight ≤50kg
Do not require bridging
with parenteral
anticoagulants
No need for routine
monitoring of
anticoagulation (will
prolong PT/PTT/INR)
blocker
Typical maintenance dose
75mg or orally per day
Typically used in patients
with history of MI or
stroke or coronary stent
placement
Binds to and inactivates
antithrombin III
Half-life of 45minutes
Easier to use, faster to
reverse
Preferable in patients with
renal insufciency
Do not interrupt therapy
with VKA in patients
undergoing procedures
with:
No clinically important
or low bleed risk; AND
Absence of patient-
related factor(s) that
increase the risk of
bleeding
Interrupt therapy with a
VKA in:
Patients undergoing
procedures with
intermediate or high
bleed risk, OR
Patients undergoing
procedures with
uncertain bleed risk
and the presence of
patient-related factor(s)
that increase the risk of
bleeding
Consider interrupting a
VKA on the basis of both
clinical judgment and
consultation with the
proceduralist and the
patient’s physician
Interrupt therapy for
intermediate, high, or
uncertain bleed-risk
procedures in:
Patients treated with
any of the approved
DOACs for a duration
based on the estimated
CrCI
restart)
When interrupting VKA therapy,
the VKA should be stopped:
3–4days prior to procedure
(for INR 1.5–1.9)
5days prior to procedure (for
INR 2.0–3.0)
At least 5days prior to
procedure (for INR >3.0)
The INR should be
re-checked within 24hours
before the procedure
Most abdominal procedures
are safe to operate with INR
<1.4
Provided adequate hemostasis
during surgery, warfarin can
be restarted as early as
12–24hours after surgery,
although timing will depend
on the indication for
anticoagulation
Duration for withholding is
based upon the estimated DOAC
half-life
Uncertain, intermediate, or
high procedural bleeding risk:
4–5 during half-lives
High-risk procedures:
Typically STOP 3 days prior
(Cr CI >50); RESUME
2–3days postop (provided
adequate hemostasis during
surgery)
Low-risk procedures:
Typically STOP 2 days prior;
RESUME 1 day postop
(provided adequate
hemostasis during procedure)
If discontinued prior to surgery:
5–7 days prior to the
procedure
Start as soon as possible
postoperatively
In preparation for surgery
Hold 6hours prior to surgery
R. G. Landmann and T. D. Francone
Management of lifethreatening bleed
For urgent surgery,
warfarin can be reversed
with vitamin K (2.5–5mg
oral or intravenous)
For emergency surgery,
warfarin can be rapidly
reversed with fresh frozen
plasma (FFP)
Management of lifethreatening bleed:
Dabigatran –
idarucizumab 2 doses of
2.5g IV no more than
15minutes apart;
activated charcoal,
supportive care; consider
4-component PCC
Apixaban, Edoxaban,
Rivaroxaban –
Andexanet alfa
(AndexXa), activated
charcoal, supportive
care, consider
4-component PCC
Platelet transfusion
Protamine sulfate
6 Preoperative Evaluation inColorectal Patients
Table 6.4 (continued)
Agent Pathophysiology When to interrupt
Heparin (low
molecular weight
heparin)
Half-life of 3–5hours
Comparable efcacy to
unfractionated heparin
Administered via
subcutaneous injection
Does not require
monitoring
Temporary interruption
recommendations (when to stop/
restart)
In preparation for surgery
Twice daily dosing– the
evening dose should be held
on the night prior to surgery
Once daily dosing– half dose
should be given on the
morning of the surgery
101
Management of lifethreatening bleed
Protamine sulfate
factors that may increase the risk for bleeding. Temporary
interruption or the omission of more than one dose of an oral
anticoagulant in preparation for a procedure is frequently
necessary to mitigate the increased bleeding risk with surgical procedures. Based on the clinical history and the type of
procedure to be performed, the risks and benets of temporary interruption should be discussed with the patient and a
collaborative discussion should occur between the patient’s
anticoagulation management team and the surgeon [11].
Two main categories of anticoagulation are utilized for
nonvalvular atrial brillation. Coumadin remains the most
widely used vitamin K antagonist (VKA). More recently,
direct oral anticoagulants (DOAC) are being frequently utilized with certain advantages over VKA including rapid
onset of action (1–3hours) and unrequired routine monitoring of anticoagulation, and most of the time bridging is not
required. Since the DOACs became clinically available,
there has been concern regarding their use due to the lack of
a specic reversal agent in case of major bleeding complications. Recently, signicant progress has been made in this
area, with the approval of the monoclonal antibody fragment
idarucizumab for the reversal of dabigatran [27, 28] and the
approval of andexanet Alfa for the reversal of apixaban,
edoxaban, and rivaroxaban [29]. Table6.4 summarizes the
most recent recommendation from the American College of
Cardiology (ACC) for management of anticoagulation in the
nonvalvular heart disease patient [11, 28]. When considering
these recommendations, the importance of collaborating
with the patient’s primary care physician or cardiologist cannot be understated, given the complexity of the decisionmaking. It is worth noting that there remains a boxed warning
regarding the association of DOACs and the increased risk of
spinal or epidural hematomas with neuroaxial anesthesia.
Therefore, DOACs should not be routinely utilized for perioperative anticoagulation if an epidural or spinal anesthesia
is planned [28].
Coronary Stent Management
The current recommendation for management of coronary
stents in patients with either bare-metal stent or drug-eluting
stent is to continue dual antiplatelet therapy (DAPT– aspirin
plus an oral antiplatelet agent such as clopidrogel, prasurgel,
and ticagrelor) for at least 12 months. The risk of stent
thrombosis in the perioperative period for both BMS and
DES is highest in the rst 4–6weeks after stent implantation.
Discontinuation of DAPT, particularly in this early period, is
a strong risk factor for stent thrombosis [30]. Should urgent
or emergency noncardiac surgery be required, a decision to
continue aspirin or DAPT should be individualized, with the
risk weighed against the benets of continuing therapy. For
patients who need to undergo nonemergent noncardiac surgery, the recommendation is to wait at least 30 days for
patients with bare-metal stents before discontinuing the anticoagulation therapy. For those patients with drug-eluting
stents, it is recommended to continue anticoagulation for
more than 6months after placement of the stent; however,
based on an individual case review, 3–6months of therapy
can be considered. During the time of discontinuing the antiplatelet therapy, it is recommended to continue low-dose
aspirin and resume the P2Y12 inhibitors as soon as possible.
These recommendations are based on data that quanties the
risk of postoperative coronary and cerebrovascular thrombotic events in this patient population (Table6.4) [28].
In situations where patients with a drug-eluting stent
require emergent abdominal surgery within 3months of stent
placement, alternative anticoagulant therapy should be considered. These patients can be safely bridged with IV infusions of short-acting antiplatelet agents such as tiroban.
Tiroban can be started within 24hours of the operation,
discontinued 4 hours preoperatively, and restarted 2 hours
postoperatively until clopidrogel is resumed. It should be
emphasized that in these special situations, coordination of
the bridging between clopidrogel and short-acting agents
requires close coordination between the surgeon, cardiologist, and anesthesiologist. [28]
Bridging
Assessment of a patient’s thrombotic and bleeding risk is
essential to determine the need for bridging therapy while
anticoagulation is being held. For the most part, bridging is
used for VKA, given DOACs typically do not require bridging. Several risk scores have been proposed to broadly evalu-
102
R. G. Landmann and T. D. Francone
Table 6.5 General recommendation on when to bridge and restart
anticoagulation therapy after surgical procedures [28]
When to Bridge
Use of bridging parenteral heparin should only be considered in the
following two scenarios:
VKA-treated patients at high risk of stroke or systemic embolism
(>10% per year), including those with a CHA
7–9 or a recent (within 3months) ischemic stroke
Determine the patient’s bleed risk to determine the appropriateness
of bridging therapy
If increased risk of bleeding, interruption of the VKA without
bridging is recommended
If NO signicant bleed risk:
(a) In patients with prior stroke, TIA, or SE, consider use of a
parenteral anticoagulant for periprocedural bridging (use clinical
judgment, likely bridge);
(b) In patients with no prior stroke, TIA, or SE, the use of a
parenteral anticoagulant for periprocedural bridging is not
advised (use clinical judgment, likely do not bridge)
Low Thrombotic Risk
(<5%/year), with a CHA
No prior history of ischemic stroke, TIA, or SE
Discontinue the VKA prior to the procedure and resume without
bridging
Moderate Thrombotic Risk
(5–10%/year) with a CHA
History of prior ischemic stroke, TIA, or
Peripheral arterial embolism (3months previously)
Parenteral bridging anticoagulation should be considered
High Thrombotic Risk
High risk of stroke or systemic embolism (>10% per year) with a
CHA
Recent (within 3months) ischemic stroke, TIA, or SE
Parenteral bridging anticoagulation should be considered
When to Restart
Restarting VAC therapy post-procedure
Before restarting oral anticoagulation therapy, ensure complete
hemostasis
VKA therapy can usually be restarted within 24hours and
parenteral heparin bridging (if indicated) within 24–72hours
depending on post-procedure bleeding risk
Restarting DOAC therapy post-procedure
Establish that hemostasis has been achieved
Following procedures with low postprocedural bleed risk, it is
reasonable to resume DOAC therapy at full dose on the day
following the procedure
Following high postprocedural bleed risk procedures, it is
reasonable to wait at least 48–72hours before resuming DOAC
therapy at full dose
DOAC dosing should reect postprocedural renal function
Bridging therapeutic anticoagulation with a parenteral agent is
generally not required
-VASc score of 7–9 or
2DS2
-VASc score of <4 or/and
2DS2
-VASc score of 5–6 or
2DS2
-VASc score of
2DS2
ate bleeding risk in patients with atrial brillation, the most
widely used of which is the HAS-BLED score (Tables 6.5
and 6.6) [31]. It incorporates hypertension; renal or hepatic
impairment; prior stroke, TIA, or systemic embolization
(SE); history of a major bleed; a labile INR; and age
>65 years. The tool is used to assess 1-year risk of major
bleeding in patients taking anticoagulants with a score of ≥3
indicating “high risk.” The CHA
-VASc score can be
2DS2
used to assess an individual patient’s overall thrombotic risk.
Table 6.6 The HAS-BLED score: Used to assess a patient’s thrombotic and bleed risk which is essential to determine the need for bridging therapy
HAS-BLED parameters
Hypertension
Abnormal renal function
Abnormal liver function
Prior stroke
History of or predisposition to (anemia) major bleeding
Labile INR (VKA)
Elderly (>65years)
Concomitant use of an antiplatelet agent or nonsteroidal antiinammatory drug
Alcohol or drug usage history (≥ drinks/week)
Additional items included in the periprocedural management
algorithm
Prior bleed event within 3months (including intracranial
hemorrhage)
Quantitative or qualitative platelet abnormality
INR above the therapeutic range at the time of the procedure (VKA)
Bleed history from previous bridging
Bleed history with similar procedure
The score incorporates multiple factors including hypertension; renal or
hepatic impairment; prior stroke, TIA, or systemic embolization (SE);
history of a major bleed; a labile INR; and age >65years [31]
Table 6.7 CHA
patient’s overall thrombotic risk
Risk factors Stroke risk per year
C Congestive heart failure +1 Point 0 0
H Hypertension +1 Point 1 1.3
A
Age ≥75
2
D Diabetes +1 Point 3 3.2
S
Stroke/TIA history +2 Point 4 4.0
2
V Vascular disease +1 Point 5 6.7
A Age 65–74 +1 Point 6 9.8
S Sex (female) +1 Point 7 9.6
It incorporates the known thrombotic risk factors into a scoring system.
As the thrombotic risk increases, the need for bridging becomes more
apparent [32]
-VASc score can be used to assess an individual
2DS2
Score % Rate per year
+2 Point 2 2.2
8 6.7
9 15.2
It incorporates heart failure, hypertension, age, diabetes,
stroke, or transient ischemic attack (TIA), vascular disease,
and female sex into a scoring system (Table6.7). The need
for bridging correlates directly with thrombotic risk but must
be evaluated against the risk of bleeding complications [32,
33]. General recommendations and guidelines for bridging
and restarting anticoagulation can be found in Table6.4 and
are in accordance to the America College of Cardiology consensus statement for perioperative management of anticoagulation [28].
Patients who have undergone cardiac valve replacement
may have received mechanical or bioprosthetic valves.
Mechanical valves require lifelong anticoagulation but are
durable and the need for a second surgery is signicantly less
6 Preoperative Evaluation inColorectal Patients
103
than with bioprosthetic valves. Anticoagulation with
mechanical valves is achieved using warfarin. Bioprosthetic
valves do not require lifelong anticoagulation and thus are
associated with fewer bleeding complications but they are
less durable and associated with higher morbidity and mortality rates. Bioprostheses require anticoagulation for
3 months unless a transcatheter aortic valve replacement
(TAVR) was performed in which aspirin and clopidrogel
may be considered an alternative. After 3months, patients
with minimal thrombotic risk may be managed on aspirin
alone with additional anticoagulation for higher risk patients.
Concomitant low-dose aspirin is recommended for patients
with mechanical valves and as sole thromboembolism prophylaxis for patients receiving aortic or mitral bioprosthetic
valves [28].
Like coronary stents, the risk of thromboembolism in the
rst few months after mechanical valve or bioprosthetic
valve repair is increased. Therefore, elective noncardiac surgery should be avoided if possible. Evidence-based guidelines exist; however, these decisions should be made in
collaboration with the patient’s cardiologist and or hematologist. In general, for minor procedures with the ability to
easily control bleeding, interruption of warfarin may not be
required. If a patient taking warfarin is to undergo a surgical
procedure that requires interruption of anticoagulation,
bridging therapy with heparin is indicated if the patient has a
mechanical aortic valve and any risk of thromboembolism.
The warfarin should be held for 5days. Bridging of anticoagulation with low molecular weight heparin (LMWH)
should begin 3–4 days preoperatively or when the INR is
<2.0. The last dose should be given 24hours prior to the
operation and an INR should be obtained the day of surgery.
Most abdominal surgeries can safely proceed with INR ≤1.4.
LMWH or an unfractionated heparin drip should be held
during the rst 48hours postoperatively or until hemostasis
is assured, while continuing standard DVT prophylaxis. The
warfarin should be restarted at the preoperative dose as soon
as possible after the procedure when deemed safe by the surgical team. If possible, continue aspirin through the perioperative stay [34].
AICD/Management
Patients with automatic implantable cardioverter debrillators (AICD) often have underlying ischemic heart disease
which should not be overlooked during the preoperative
assessment. It is critical for both the surgeon and the anesthesiologist to communicate with the patient’s cardiologist and
for the anesthesiologist to nd out whether the patient is pacemaker-dependent versus independent. Some patients may
have pacemaker-dependent atrial, ventricular, or both chambers paced 100% of the time. For these patients, the device
may need to be reprogrammed intraoperatively. For those
patients who are not pacemaker dependent, the anesthesiolo-
gist should place a magnet over the device which will prevent
inappropriate delivery of shocks and trigger of arrhythmic
events. All AICD patients should have an external debrillator and transcutaneous pacer immediately available and the
electroconductive pad afxed to the patient at the start of the
case. In the emergent settings, in which a formal cardiology
consult is not feasible, a 12-lead EKG can be used to determine pacemaker dependence. Of note, the AICD activity can
be affected by monopolar cautery causing electromagnetic
interference. This can result in delivery of a shock to the
patient or inadequate or inappropriate pacing. Minimal use of
monopolar cautery and preferential use of alternative devices
such as bipolar or ultrasonic energy can help decrease the risk
of electromagnetic interference [28, 35].
Pulmonary Assessment
Postoperative pulmonary complications contribute signicantly to overall morbidity and mortality. Complications
may include atelectasis, infection, including bronchitis and
pneumonia, hypoxemia, exacerbation of underlying chronic
obstructive pulmonary disease (COPD), asthma, or respiratory failure (mechanical ventilation for >48hours after surgery or unplanned reintubation). The reported frequency of
postoperative pulmonary complications in the literature varies from 2% to 70% with one study utilizing the NSQIP database demonstrating a 6% rate of pulmonary complications in
165,196 patients who underwent major abdominal surgery
[36]. A more recent multicenter prospective observational
study by Fernandez-Bustamante etal. evaluated postoperative pulmonary complications (PPC) in 7 US academic institutions. The study demonstrated that at least one PPC
occurred in 401 patients (33.4%), the majority of which
included patients requiring prolonged oxygen therapy by
nasal cannula (n = 235; 19.6%) and atelectasis (n = 206;
17.1%). Patients with one or more PPCs had signicantly
increased early postoperative mortality, intensive care unit
(ICU) admission, and ICU/hospital length of stay [37].
Preoperative optimization is the best way to minimize
risk. Routine pulmonary function tests are NOT indicated for
healthy patients prior to surgery. Clinical ndings are more
predictive of the risk of postoperative pulmonary complications than are spirometric results. These ndings include
decreased breath sounds, prolonged expiratory phase, rales,
rhonchi, or wheezes. Tests generally should be reserved for
patients who have dyspnea that remains unexplained after
careful clinical evaluation or other high-risk factors. Risk
factors for pulmonary complications can be grouped into
patient-related and procedure-related risks. Chronic obstructive pulmonary disease (COPD) has been demonstrated to be
the single most important risk factor for development of
postoperative pulmonary failure. Up to 25% of elderly
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R. G. Landmann and T. D. Francone
patients with COPD have an operative pulmonary complication, with mortality approaching 7% [21]. Other patientrelated risk factors include advanced age, American Society of
Anesthesiologists class 2 or higher, functional dependence,
elevated Goldman Cardiac Risk Index [38], and congestive
heart failure. Interestingly, obesity is not a pertinent risk factor
[21]. Procedure-related risk factors include aortic aneurysm
repair, non-resective thoracic surgery, abdominal surgery, neurosurgery, emergency surgery, general anesthesia, head and
neck surgery, vascular surgery, and prolonged surgery [13].
Patients with increased risk factors should be evaluated
by their primary care physicians and/or pulmonologists if
they see a specialist. Bronchodilators should be continued
perioperatively. Glucocorticoid use must be balanced against
potential increased risk for complications such as anastomotic leak. In patients with history of tobacco abuse, smoking cessation for more than 6–8weeks is recommended [20].
If patients pursue smoking cessation, duration needs to be
greater than 2months; otherwise, risk of pulmonary complications is signicantly increased. This includes patients who
cut down before surgery, with relative risk of 6.7 for individuals undergoing major non-cardiac surgery [39].
Obstructive sleep apnea is one of the most common sleep
disorders and is characterized by upper airway obstruction
causing apneic episodes. It is important to recognize obstructive sleep apnea preoperatively as it is a risk factor for perioperative cardiopulmonary complications and can be associated
with unplanned ICU admissions [40]. Patients undergoing
major abdominal surgery should be screened and managed
for obstructive sleep apnea, similar to those patients with high
BMI and multiple comorbidities. Common symptoms of
sleep apnea include loud snoring, daytime sleepiness, and
witnessed apnea by a sleep partner; however, other symptoms
may include morning headaches, poor concentration, altered
mood, vivid or disturbing dreams, restless sleep, GERD, and
nocturia. Screening tools are available such as the STOPBang questionnaire, in which patients with high scores may
be referred to a pulmonologist for formal workup [41].
Perioperative Steroid Management
Colorectal surgeons will often encounter patients on chronic
steroid therapy as it is a primary treatment for many conditions such as inammatory bowel disease, rheumatologic disease, reactive airway disease, and immunosuppression for
transplant recipients. Due to the increased physiological
stress, patients on chronic steroid therapy are at risk for developing secondary adrenal insufciency that may manifest as
an adrenal crisis in the perioperative period. Signs and symptoms of adrenal crisis may include altered mental status/psychosis, abdominal pain, nausea/vomiting, weakness, and
hypotension. In addition to suppression of the hypothalamicpituitary-adrenal (HPA) axis, the potential adverse effects of
perioperative glucocorticoids are numerous. Adverse effects
can include impaired wound healing; increased atrophy and
tearing of skin, supercial blood vessels, and other tissues;
increased risk of fractures, gastrointestinal hemorrhage, ulcer;
and increased postoperative infections such as anastomotic
leak. The surgeon, in collaboration with anesthesiology, will
need to consider whether the benet of administering perioperative stress dose steroids to mitigate the risk for an adrenal
crisis outweighs its potential risks [42].
The decision to administer supplemental exogenous stress
glucocorticoids is not always straightforward and there is a
lack of data regarding standard protocols. This is in part related
to the lack of data demonstrating the dose or duration of exogenous steroids required to cause a dysfunction in the HPA
access. Prednisone, 20mg/day, or its equivalent for more than
3 weeks, has been cited as the most common dose causing
suppression. The exact time course of recovery from HPA axis
suppression may differ between individuals; however, most
agree that suppression does not continue beyond 1 year after
cessation of exogenous steroid therapy, except for patients
receiving intraarticular glucocorticoid injections [42].
Several approaches to glucocorticoid dosing have been
proposed. These protocols categorize patients into high-,
intermediate-, and low- risk groups for HPA-axis suppression or stratify based on the anticipated surgical stress associated with a minor, moderate, or major surgery (Table 6.8).
Of note, patients who have diagnosed secondary adrenal insufciency, as demonstrated by the short- acting ACTH test, will
require perioperative stress-dose steroids with dosing based on
surgical stress risk. Hydrocortisone is the drug of choice for
acute stress and rescue-dose steroid coverage [42].
Recent data suggest that stress-dose steroids may not be
necessary [43]. Instead, these patients may be maintained on
their usual preoperative dose and treated with rescue dose steroids only if refractory hypotension presents in the perioperative period. In 2012, a retrospective cohort study of patients
with inammatory bowel disease undergoing surgery demonstrated that patients who received only low-dose perioperative
steroids (the equivalent of their preoperative dose given intravenously) did not require vasopressors for hemodynamic
instability or additional steroids for adrenal insufciency [44].
Similarly, in a randomized trial of patients undergoing major
colorectal surgery, no differences in postural hypotension or
adrenal insufciency were seen between those receiving highdose glucocorticoids (hydrocortisone 100 mg intravenously
three times daily) or low-dose glucocorticoids (the equivalent
of their preoperative dose given intravenously) [45]. Although
this data is promising, perioperative stress-dose steroid administration appears to carry minimal risk compared to the risk of
adrenal crisis. Hence, patients who are at risk for HPA-axis
suppression should be considered for steroid replacement
therapy in the perioperative setting [42].
Diabetes
Diabetic patients represent a complex subset of surgical
patients, who often have long-term complications of their
6 Preoperative Evaluation inColorectal Patients
105
Table 6.8 Several approaches to glucocorticoid dosing have been proposed which categorize patients into high-, intermediate-, and low- risk
groups for HPA-axis suppression or the anticipated surgical stress associated with a minor, moderate, or major surgery [42]
Surgery
type Examples Recommendations
Supercial Dental surgery
Biopsy
Minor Inguinal hernia repair
Colonoscopy
Anorectal surgery
Uterine curettage
Hand surgery
Moderate Lower extremity
revascularization
Total joint replacement
Cholecystectomy
Colon resection
Abdominal hysterectomy
Major Esophagectomy
Total proctocolectomy
Major cardiac/vascular
procedures
Hepaticojejunostomy
Trauma
Risk for HPAA Suppression Recommendations
Low Treated with any dose of
glucocorticoid for less than
3weeks
Morning doses of
prednisone 5mg/day or
less
Prednisone 10mg/day
every other day
High Patients who have been
treated with a
glucocorticoid in doses
equivalent to at least
20mg/day of prednisone
for more than 3weeks or
who have clinical features
of Cushing syndrome
Usual daily dose
Daily dose plus
hydrocortisone (25mg
IV)
Daily dose plus
hydrocortisone
(50–75mg IV; taper
1–2days)
Daily dose plus
hydrocortisone
(100–150mg IV; taper
1–2days)
Perioperative stressdose steroids are not
required unless they
exhibit signs of HPAA
suppression
Patients would benet
from perioperative
stress-dose steroids
with dosing based on
surgical stress
disease (neuropathy, visual impairment, peripheral, and mesenteric vascular disease), as well as other related comorbidities, such as chronic renal insufciency and cardiovascular
disease [5, 46] that can signicantly impair perioperative
outcomes. The initial ofce consultation with the surgeon
should include a detailed history, focusing on the type and
duration of diabetes, symptoms, how glucose is monitored at
home, baseline glucose range, glycated hemoglobin (Hgb
A1c) levels, related symptoms, as well as the contact information of their primary care physician and/or endocrinologist. Diabetic patients undergoing major abdominal surgery
should have the following as part of their preoperative
workup: ECG, CXR, serum creatinine, serum glucose, and
an A1c level (within 4–6weeks preoperatively). In particular, elevated A1c levels have been shown in cardiac surgery
to be associated with increased risk of surgical complica-
tions, including infections, myocardial infarction, and death
[47]. Close perioperative involvement of the anesthesiologist
is also critical, as some patients undergoing major operations
will require preoperative intravenous insulin infusion to
attain euglycemia prior to initiation of surgery [48].
Additionally, these same patients may require insulin administration intraoperatively. The surgeon should be cognizant
that most operations cause a catabolic state with elevated
blood sugars. These elevated glycemic levels may be signicantly more pronounced in a preexisting diabetic patient and
necessitate attention postoperatively. All diabetic patients
should be maintained on a postoperative insulin sliding scale
regimen, in addition to their home medications. Perioperative
elevated blood sugars are concerning as they may lead to
perioperative wound infections and anastomotic dehiscence.
Due to the cardiac complication rates, as well as increased
incidence of septic sequelae, many centers will postpone
operations in patients with elevated Hgb A1c levels >6.5
until improved blood sugar control can be achieved [49, 50].
Obesity
More than one-thirds of adults in the USA are obese, which
is dened as having body-mass index (BMI) of 30kg/m2 or
more. One in 20 adults is considered super-obese (BMI of
40kg/m2 or more) [51]. BMI is considered a screening tool
to identify obesity and is calculated as the patient’s weight
(in kilograms) divided by square of the height (in meters).
The obese patient creates substantial technical challenges for
the surgeon. In terms of postoperative morbidity, obese
patients undergoing nonbariatric abdominal surgery have
been shown to have increased risk of perioperative venous
thromboembolism and supercial site infection. A prospective study of over 6000 patients found that the risk of supercial site infection after open abdominal surgery was 4% for
obese versus 3% for nonobese patients, P=0.03 [52]. Other
studies based on ACS-NSQIP data demonstrated incremental odds of surgical site infection with progressive classes of
obesity, as well as increased wound disruption, sepsis, respiratory or renal complication, and urinary tract infection [53].
Studies have demonstrated increased thromboembolism,
supercial site infection rates, and inability to create pouches
or anastomoses to the lower rectum or anus in obese population [53–56]. Obesity also signicantly increases operative
time in colorectal procedures [55, 56]. Most importantly,
obesity has been demonstrated to increase anastomotic
(pouch-anal) leak rate [56].
Obese patients pose signicant intraoperative challenges,
some of which can be mitigated with appropriate preoperative planning. Much of the difculty in operating on patients
with obesity is due to the visceral adiposity and bulky mesentery, leading to difcult intraabdominal and pelvic exposure as well as manipulation and reach of the visceral
contents [56]. For example, if a stoma may be needed, a visit
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R. G. Landmann and T. D. Francone
from the enterostomal therapist is extremely important, as
marking on the slightly thinner upper abdomen will be helpful. It is especially important to ensure that these patients can
reach their stoma, so they can care for it independently. Both
laparoscopic and open surgeries are technically demanding
in obese patients; however, if feasible, performance of laparoscopic surgery has the advantage of smaller incisions, less
pain, and improved visualization for the surgeon. Avoiding
lower midline and Pfannenstiel incisions is helpful in minimizing supercial site infections and other wound-related
complications in obese patients with a large pannus. Clear
communication with the operating room staff prior to the
case is essential to ensure availability of long instruments,
deep retractors, appropriate beds, and equipment such as
blood pressure cuffs and large pneumatic compression boots.
Due to the increased risk associated with operative outcomes
in patients with obesity, many have advocated for weight loss
preoperatively, and in some cases recommended bariatric
surgery, to promote optimal outcomes [57, 58].
As will be discussed later, obesity itself does not predispose a patient from being malnourished. Indeed, the opposite
can be quite true, and many patients with obesity demonstrate protein calorie malnutrition and sarcopenia, as demonstrated by low albumin and prealbumin levels as well as
muscle wasting on cross-sectional imaging [59, 60]. Methods
to reduce visceral and systemic adiposity while improving
protein stores preoperatively are imperative to improve operative and postoperative outcomes [61]. Options include very
low calorie diets, pharmacotherapy, or metabolic surgery.
These allow for reduction in adiposity of the mesentery,
shrinkage of the liver, and downsizing of the fat pads in the
lower pelvis – all thereby permitting better exposure and
visualization of the intraabdominal and pelvic spaces, safer
identication of critical structures, and improved mobilization of the colon and/or small bowel for improved reach
when required for more distal anastomoses [62].
It should be noted that in the setting of malignancy,
increasing length of time to surgery while optimizing the
patient status has no effect on disease-specic survival.
Indeed, this preoperative management and prehabilitation
intervention improve the patient’s overall physiological status and subsequently reduce postoperative complications
and mortality, while lowering the length of stay [58].
Malnutrition
Colorectal surgeons are commonly faced with challenging
patients who are malnourished due to advanced malignancies or inammatory bowel disease that results in intestinal
blockages, intestinal stulas, poor absorptive capacity, and
large volume losses from the GI tract. Nutritional risk tends
to be a reection of the patient’s overall health and in oncology has correlated with the Eastern Cooperative Oncology
Group score and the presence of anorexia or fatigue [63].
Such nutritional risk is associated with increased postoperative complications, longer length of stay, and higher mortality following elective surgery [64, 65] and is particularly
pronounced in patients with colorectal cancer [66]. Incidence
remains under-recognized and malnutrition continues to
negatively impact postoperative recovery and patient outcomes, as well as mortality [67]. Although logistically challenging, nutritional support can be delivered in the
preoperative or postoperative setting and can be administered via the enteral and parenteral routes. Most studies are
limited by heterogeneous patient populations, variable study
designs, different feeding protocols that often result in parenteral overfeeding, and outdated methodologies. When
delivered appropriately, malnourished colorectal patients
realize several benets from perioperative nutritional support including fewer postoperative complications, shorter
hospital length of stay, and lower mortality [68].
The evaluation of potentially malnourished patients
begins with the history and physical examination. Most
patients will complain of some degree of intolerance of oral
intake as a result of poor appetite, nausea, abdominal bloating, abdominal pain, and weakness. Patients will relate a
recent weight loss, typically over a 1–3month time period.
On physical examination, the patient appears thin, pale, and
weak with muscle wasting and loose skin. These variables
can be objectied using grading systems such as the relatively intuitive Subjective Global Assessment (SGA) to classify patients as well nourished, moderately malnourished, or
severely malnourished [69]. The SGA utilizes ve features
of the history (weight loss over 6 months, dietary intake
change, gastrointestinal symptoms, functional capacity, and
the impact of disease on nutritional requirements) and four
features of the clinical exam (loss of subcutaneous fat, muscle wasting, ankle edema, sacral edema, ascites) to elicit an
SGA rank based on subjective weighting. Serum albumin
level has been considered the “classic” test reecting overall
nutritional status, with serum concentration <4.0g/dL dening the “malnourished state.”
Recent groups have recommended that hypoalbuminemia, with levels below 4/dL, serves as a negative prognostic
marker for adverse postoperative outcomes including mortality and serious morbidity. These authors have recommended adding hypoalbuminemia as a risk factor when
utilizing the ACS-NSQIP Surgical Risk Calculator to
improve estimation of surgical risks to patients and surgeons
[70]. However, in real practice, its utility and reliability are
limited as levels uctuate for many reasons, including production alterations in the catabolic or anabolic states, external losses, or redistribution between the various uid
compartments of the body [71]. Other short turnover proteins
such as prealbumin, transferrin, and retinol-binding protein
have similar limitations as nutritional markers as a result of
variable half-lives and response to dietary intake and renal/