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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3795_Библиотеки_им_академика_М_И_Перельмана
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and thrombosis were thought to be associated with the NC cusp. In the NC sinus, the suturing
plane should be intentionally elevated by 1–2 mm, but care must be taken to follow the
annular line (and not to create a straight line). It was also suggested to begin suturing the NC
sinus by applying only the first 2–3 stitches on each side, in order to assure tension-free
seating of the prosthesis on a nonwrinkled aortic sinus under perfect exposure, and then to
continue with the right and left sinus, and finally complete the NC sinus suture line. In our
opinion, the key is to perform correct and tension-free sutures comfortably, regardless of the
sequence. We have made it routine to check for folding and leaks with a small instrument
(nerve hook). Additional stitches to correct for folding or suspected leaks can be made
through the prosthesis and with the knot tied outside the aorta.
Notes: (A) Transverse aortotomy, 3 string sutures at the level of the commissures and sizing. (B) The
first three stitches are passed at the nadir of each sinus and through the pericardial rim of the tissue
valve. (C) The valve is parachuted down into the aortic anulus. (D) The first stitch is demonstrated
at the nadir of the sinus. (E) The continuous suture is performed in direction of the commissure.
(F) This picture demonstrates the sequence of suturing the tissue valve. Starting below the right
coronary artery and moving to both commissures (1, 2, and 4) then below the left coronary artery
(3 and 5) and finally suturing the non-coronary leaflet at the end (6 and 7). A, right-coronary cusp;
B, left-coronary cusp; C, non-coronary cusp. (G) Tying of the sutures is performed outside the
aorta at the level of the three commissures. (H) Final view of the supraanular, subcoronary
continuous suture line from inside the aorta. (I) Final view from outside the aorta with
demonstration of a maximized central and homogeneous flow through the valve.
Reprinted from Stanger O, Tevaerarai H, Carrel T. The Freedom SOLO bovine pericardial stentless
valve. Res Rep Clin Cardiol. 2014;5:1-13.
Figure 1. Implantation technique of the Freedom SOLO stentless valve.
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Sutureless and Rapid Deployment Prostheses
We describe these two new technologies in Chapter 18.
Ross Procedure
Pulmonary autograft harvesting
Once the decision to replace the aortic valve has been confirmed, a transverse incision is
made on the main pulmonary artery (PA) 5 mm proximal to the origin of the right PA. The
pulmonary valve is inspected and will be used only if it has a normal-appearing trileaflet
configuration with no major fenestrations. The PA is transected and freed from the aortic root
down to the right ventricular muscle. Using a right-angle clamp through the pulmonary valve,
the right ventricle is poked approximately 5 mm below the nadir of the non-facing cusp. The
pulmonary root is then carefully harvested, leaving no more than 5 mm of infundibular
muscle under the insertion line of the leaflets. By staying close to the leaflets, injury to the
first septal artery is greatly minimized. After harvesting the pulmonary autograft, the
infundibular muscle is trimmed leaving 2 mm below the insertion of the cusps and cut 2–3
mm above the level of the STJ to avoid exposing the PA to systemic pressures.
Pulmonary autograft implantation
As with stentless roots, both total root replacement and subcoronary implantation
techniques can be used. We favor the total root technique. The autograft is implanted in a subannular position using single interrupted 4-0 polypropylene sutures, while ensuring
symmetrical spatial distribution of the commissures. Distal autograft anastomosis to native
aorta or Dacron graft is performed using 5-0 polypropylene sutures. The coronary buttons are
reimplanted in their corresponding sinuses using 6-0 polypropylene sutures. If the aortic
annulus is more than 2 mm larger than the pulmonary annulus, an extra-aortic ring
annuloplasty is performed to educe the size of the native aortic annulus. The coronary ostia
are anastomosed to their respective sinuses. Following surgery, strict blood pressure control is
immediately instituted and maintained for the first 6–12 months to allow adaptive remodeling
of the autograft. Maximum target sys- tolic blood pressure should be 100–110 mmHg.
Pulmonary homograft implantation
The largest pulmonary homograft available is always used to replace the pulmonary root
(28–30 mm), irrespective of the original pulmonary annulus diameter. Proximal and distal
implantation is made with a standard running suture. Care is taken to avoid purse-stringing
the distal suture line between the pulmonary homograft and the main PA.
Aortotomy Closure and De-airing
The aorta is closed using a running 4-0 polypropylene suture. Before unclamping the
aorta, de-airing maneuvers are performed. The left ventricular vent is stopped, Valsalva
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maneuvers are initiated, and root suction is started while manually shaking the heart to
dislodge air bubbles from the left-sided chambers. The cross-clamp is then removed. If
continued until it can no longer be observed.
MINIMALLY INVASIVE TREATMENT
Principles and Advantages
The main principle of minimally invasive surgery (MIS) AVR surgery is to perform a
safe and effective aortic valve procedure, without an increase in complication rates. The key
to this goal is a well-planned approach that will lead to good exposure of the aortic valve.
Speed of the procedure should not be the primary concern of the surgeon, particularly early in
his/her experience. The increased operative times associated with MIS are not clinically
relevant in the majority of patients requiring isolated AVR surgery. Although a definite
learning curve exists for MIS AVR surgery, it is less than for many other cardiac operations
(e.g., MIS mitral valve surgery, complex aortic procedures, high-risk reoperative surgery). In
addition, improvements in low- and high-fidelity surgical models, increased surgical
mentoring, and establishment of peer-to-peer MIS learning centers should help mitigate the
learning curve effect for future cardiac surgeons. Several lines of evidence justify the
performance of MIS AVR surgery. As stated above, several studies have demonstrated
clinical benefits associated with this operation. A meta-analysis of 4667 patients
demonstrated a statistically significant reduction in ventilation time, blood loss, ICU stay,
supraventricular arrhythmia rate, hospital stay, and early mortality rate in patients undergoing
MIS AVR procedures [1]. However, myocardial ischemic and CPB times were longer in the
MIS group, with an average of 9 and 11 minutes, respectively. A large retrospective study
from Leipzig also suggested improved long-term survival in propensity-matched MIS AVR
patients, although the mechanism behind this observation is unclear [2]. Several other reasons
may justify the performance of MIS AVR surgery.
Some studies have demonstrated additional clinical benefits other than those listed
above, including decreased transfusion rates, decreased pain, decreased sternal
infection rate, better quality of life, and shortened return to work times.
The history of cardiovascular interventional medicine demonstrates that patients
prefer less invasive procedures. Increased acceptance by patients and their family
members may result in better psychological preparation for their cardiac operation, as
well as increased motivation for a faster postoperative recovery.
The decreased surgical exposure (particularly of the right atrium and ventricle) leads
to decreased postoperative adhesions and easier re-entry in the case of future
reoperation.
The additional technical skills that surgeons acquire during MIS AVR surgery are
similar to those required for many other types of less invasive cardiovascular
interventions, which are likely to increase in number in the future.
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Establishment of a successful MIS program may result in increased patient referrals
and increased recognition from referring cardiologists and surgical peers.
Preoperative Assessment and Preparation
Preoperative assessment for patients undergoing a MIS AVR procedure is similar to that
for all patients undergoing AVR surgery including transthoracic echocardiography (TTE),
chest X-ray (CXR), routine blood work, and cardiac catheterization for patients. Thoracic
computed tomography (CT) scan without contrast medium injection is a routine preoperative
screening facility in our department before AVR to choose the appropriate surgical approach
for the patient. In the last 3 years, we prefer CT scan with contrast to better evaluate the
characteristics of the native valve and to measure the aortic annulus. Generally, relative
dextraposition of the ascending aorta (at least 50% of the calliper beyond the right parasternal
line in the right part of the thorax at the level of the pulmonary trunk bifurcation) and
moderate profoundness of the aortic root (not >10 cm from skin to the aortic valve annulus)
provide optimal surgical exposure for the right minithoracotomy. Otherwise, the patient is
eligible for upper ministernotomy or full midline sternotomy. However, thanks to technical
feasibility of sutureless and rapid deployment valves implantation, these criteria are of
relative importance now. Exclusion criteria for right anterior minithoracotomy approach were
severe thorax deformities, right pleural cavity adhesions, severe COPD complicated by
emphysema, or technical impossibility for peripheral percutaneous venous cannulation.
Anesthesia
A single lumen endotracheal tube is sufficient for both of the most common MIS AVR
approaches (i.e., ministernotomy and right anterior minithoracotomy). If the lung interferes
with exposure during the minithoracotomy approach, then a moist sponge placed in the right
pleura will suce. Endocavitary wires for temporary pacemaker are inserted in internal jugular
vein. Some surgeons request that the anesthesiologist insert a percutaneous retrograde
cardioplegia catheter in the coronary sinus prior to starting the procedure, but we find this to
be unnecessary and cumbersome. We prefer antegrade cardioplegia via the aortic root or
coronary ostia. Patients can be extubated according to institutional protocol.
Ministernotomy: Surgical Technique
A skin incision 6–8 cm in length is made starting 1–2 cm above the sternal manubrium
junction and extending 5–7 cm toward the xiphoid. The incision is continued from the skin
down to the sternum with electrocautery. The sternal saw is used to divide the sternum
midline from the sternal notch to the level of the third intercostal space. Division of the
sternum is then either continued as a “J” or “T” to the third intercostal space. Four pericardial
stay sutures are placed at the four “corners” of the incision, then pulled up with force in order
to bring the mediastinal structures closer to the skin. We prefer percutaneous cannulation of
the femoral vein under echocardiographic guidance (Figure 2).
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Figure 2. Percutaneous femoral vein cannulation.
A Finochietto retractor is inserted and pericardial stay sutures are placed. Percutaneous
femoral venous cannulation has the advantage of completely eliminating the cannula from the
surgical field, but risks the complications of peripheral cannulation (i.e., injury to the deep
venous structures or local groin complications). Once CPB has been initiated, venous
drainage is assisted with vacuum pressure. In our experience, the total negative pressure is
maintained at no greater than -40 mmHg. Aortic cannulation is performed in the standard
manner.
Figure 3. Ascending aorta cannulation.
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Since vacuum-assisted cardiopulmonary bypass was established, a left ventricular vent
was placed through the right superior pulmonary vein. A needle vent is used for administering
antegrade cardioplegia, as well as to assist in de-airing the heart at the conclusion of the case.
We do not use retrograde cardioplegia because of difficulties in positioning the catheter via
the MIS approach, as well as obscuring of the operative field from blood that runs out of the
coronary ostia. The ascending aorta was clamped with the Cygnet cross-clamp (Novare
Surgical Systems, Cupertino, California). We prefer to administer normothermic blood
cardioplegia or cold crystalloid solution (Custodiol Koehler Chemie, Alsbach-Haenlein,
Germany).
Transverse aortotomy was performed approximately 2 cm above the commissures and
aortic valve was inspected. The aortic valve leaflets were totally excised and the aortic
annulus decalcified. Three stay sutures may be placed at the top of each commissure in order
to improve valve exposure. Annular non-everting pledgeted mattress sutures are placed in a
standard fashion, with the pledgets on the ventricular side of the annulus for the bioprosthesis
or on the aorta side of the annulus for the mechanical prosthesis. The valve prosthesis is
lowered into place. Once the valve sutures have been tied, the coronary ostia are checked to
ensure patency. The space between the annulus and the sewing ring is also probed
circumferentially, in order to assess for a possible paravalvular leak. The use of sutureless
aortic valves and automatic knotting devices may simplify these stages of the procedure. The
aortotomy is closed with a single layer using a 4-0 polypropylene suture. Prior to removal of
the aortic cross-clamp, de-airing techniques are performed. The heart is filled with venous
blood, the left ventricle is compressed and the lungs are inflated with sustained positive
pressure. In addition, manual compression over the left ventricular apex may be applied
externally. The left ventricular vent is stopped prior to these maneuvers, and the needle vent
is applied to high suction immediately prior to opening of the cross-clamp. The left
ventricular vent is applied to gentle suction following cross-clamp removal. Once the aortic
cross clamp is removed, intracavitary air is assessed by transesophageal echocardiography
(TEE). Chest tube should be placed when the right ventricle while it is completely
decompressed, prior to coming off CPB. When TEE confirms adequate de-airing of the left
ventricle, the patient is weaned from CPB in a standard fashion. Once surgical hemostasis has
been confirmed, protamine is administered. The sternum is closed with sternal wires. The skin
and subcutaneous tissue are closed using a standard technique.
Right Anterior Minitoracothomy: Surgical Technique
RAMT was performed through an incision (5-6 cm) in the second intercostal space. In
patients with associated mitral and tricuspid procedures, third intercostal space anterior
minithoracotomy was preferred. The soft tissue retractor are used to open the working field. A
Finochietto retractor is inserted and pericardial stay sutures are placed. Some surgeons prefer
detache third rib. Direct aortic cannulation was performed using low-profile cannulas. Venous
drainage was achieved with a variety of percutaneous venous cannulas inserted through the
femoral vein into the venae cavae. The correct placement of the venous cannula was obtained
using the Seldinger technique under transoesophageal echocardiographic guidance. Vacuumassisted venous drainage can facilitate venous return. Since vacuum-assisted cardiopulmonary
bypass was established, a left ventricular vent was placed through the right superior
pulmonary vein, and the patients were cooled down to 34 or 35°C. The ascending aorta was
clamped with the Cygnet cross-clamp (Novare Surgical Systems, Cupertino, California).
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Antegrade cardioplegic solution was given into the aortic root or selectively into the coronary
ostia using normothermic blood cardioplegia or cold crystalloid solution. In all cases of
RAMT, the surgical field was flooded with carbon dioxide at a flow of 0.5–1.0 l/min. The
procedures of decalcification and prosthesis implantation are the same as for ministernotomy
and full sternotomy. At the end of RAMT procedure, we prefer juxtaposed the second (or
third, in case of mutliple procedures) intercostal space with non-absorbable stitches. The skin
and subcutaneous tissue are closed using a standard technique (Figure 4).
Figure 4. Final result of RAMT approach.
OUTCOMES IN MINIMALLY INVASIVE AORTIC SURGERY
The evidence to date shows that MIS AVR can be performed safely and effectively and is
associated with several clinical advantages. Potential drawbacks of MIS AVR, however,
include increased operative, bypass, and cross-clamp times, particularly during the early
portion of the surgeon’s experience. Multiple studies have compared outcomes of
conventional versus MIS AVR in a prospective and retrospective fashion. Doll et al. [3]
retrospectively compared 175 patients who underwent MIS AVR to 258 patients who
underwent conventional AVR via full sternotomy. Patients who underwent MIS AVR had
decreased morbidity and mortality, lower incidence of respiratory failure, shorter ICU and
hospital length of stay, and less transfusion requirements at the expense of slightly longer
cross-clamp time (5 minutes) and operating room time (14 minutes), but no significant
difference in CPB time. Patient selection bias limits the interpretation of such retrospective
studies, but subsequent small, randomized controlled trials have largely confirmed their
results. A large, single-center study by Tabata et al. [4] involving 1005 patients showed
excellent short-term and long-term outcomes for MIS AVR out to 11 years postoperatively.
Of note, this study also included 130 patients (13%) who underwent reoperative AVR and 62
patients (6%) who had concomitant ascending aortic surgery, highlighting the potential for
this technique in more complex procedures. The authors achieved excellent results with a
median length of stay of 6 days, operative mortality rate of 1.9%, and reoperation for bleeding
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rate of 2.4%. In addition, pneumonia was observed in only 1.3% of patients and deep sternal
wound infection in 0.5%. Also notable was a significant decrease in CPB time, incidence of
bleeding, and operative mortality over time, confirming the presence of a learning curve
associated with this approach. Bakir et al. [5] also reviewed their results of 506 patients who
underwent MIS AVR compared to conventional AVR and found that the MIS patients had
shorter cross-clamp and CPB times, less blood loss, and shorter hospital stay. Similarly,
Glauber et al. [6] used propensity matching to compare their results of 192 MIS AVR patients
(using a right anterior minithoracotomy approach) to patients undergoing conventional AVR.
The MIS patients had a lower incidence of atrial fibrillation and blood transfusions, shorter
ventilation duration, shorter length of stay, and no difference in mortality. A recent large
propensity-matched study by Merk et al. [2] compared 479 MIS AVR patients to matched
controls. MIS patients had better medium-term survival compared to matched conventional
AVR patients (5-year survival 89.3 ± 2.4% vs 77.7 ± 4.7%) with a hazards ratio of 0.47 on
Cox-regression analysis. The study also demonstrated less bleeding in MIS patients while
cross-clamp times were slightly longer (3 minutes), similar to the results of previous studies.
Few randomized controlled trials examining MIS AVR compared to conventional approach
exist to date. However, Bonacchi et al. [7] randomized a total of 80 patients to the two
techniques and demonstrated no significant differences in CPB or cross-clamp times between
groups but longer total operating time in the MIS patients. MIS patients also had fewer
transfusions, shorter ventilation times, decreased pain at 1 hour and 12 hours postoperatively,
and better lung function 5 days postoperatively. Machler et al. [8] randomized 120 patients to
MIS or conventional AVR and showed no difference in cross-clamp, CPB, or operating
times. However, MIS AVR patients had shorter ventilation times, less blood loss, and less
analgesic use. A meta-analysis by Murtuza et al. from 2008 [1] showed marginal benefits in
perioperative mortality (odds ratio, OR, 0.72 [range: 0.51–1.0], p = 0.05), but statistically
significant shorter ICU and lengths of hospital stay, decreased ventilation duration, and
decreased transfusion requirements, at the potential expense of longer cross-clamp, CPB, and
total operating times in MIS AVR patients.
In conclusion, MIS AVR surgery is associated with an improved survival, cosmetic result
and decreased bleeding, pain, and ICU/hospital length of stay, but it is associated with longer
cross-clamp and CPB times. In the last years, new technologies (Sutureless and Rapid
Deployments) have limited significantly ACC and CPB times (We discusse this aspect in
Chapter 18). Although MIS AVR can be performed safely, a learning curve exists and
surgeons should be aware of potential pitfalls in both patient selection and operative
techniques.
REFERENCES
[1] Murtuza B, Pepper JR, Stanbridge RD, et al. Minimal access aortic valve replacement:
is it worth it? Ann Thorac Surg. 2008; 85: 1121–31.
[2] Merk DR, Lehmann S, Holzhey DM, et al. Minimal invasive aortic valve replacement
surgery is associated with improved survival: a propensity-matched comparison. Eur J
Cardiothorac Surg. 2015; 47(1): 11–17.
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[3] Doll N, Borger MA, Hain J, et al. Minimal access aortic valve replacement: effects on
morbidity and resource utilization. Ann Thorac Surg. 2002; 74(4): S1318–22.
[4] Tabata M, Umakanthan R, Cohn LH, et al. Early and late outcomes of 1000 minimally
invasive aortic valve operations. Eur J Cardiothorac Surg. 2008; 33: 537–41.
[5] Bakir I, Casselman FP, Wellens F, et al. Minimally invasive versus standard approach
aortic valve replacement: A study in 506 patients. Ann Thorac Surg. 2006; 81: 1599–
604.
[6] Glauber M, Miceli A, Gilmanov D, et al. Right anterior minithoracotomy versus
conventional aortic valve replacement: A propensity score matched study. J Thorac
Cardiovasc Surg. 2013; 145: 1222–6.
[7] Bonacchi M, Prifti E, Giunti G, et al. Does ministernotomy improve postoperative
outcome in aortic valve operation? A prospective randomized study. Ann Thorac Surg.
2002; 73: 460–5.
[8] Machler HE, Bergmann P, Anelli-Monti M, et al. Minimally invasive versus
conventional aortic valve operations: aprospective study in 120 patients. Ann Thorac
Surg. 1999; 67: 1001–5.
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