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Thrombolysis for Acute Lower Limb Ischemia 283
• Patients usually seek medical help sooner than do those in the viable category
• Examination:
b
Signs of coldness and pallor are more advanced than in the viable category
b
Sensory Function
Loss to even light touch qualifies for THREATENED
Can use readily available Kleenex to test for asymmetry leg to leg
More serious (worse) if there is loss of sensation to pin prick
• Unable to differentiate between sharp and dull ends of pin
More serious (worse) if patient can only sense deep pressure (squeezing of
foot)
More serious (worse) if loss of proprioception (toe position)
Put in Profound/Irreversible category if anesthetic (only 10% of cases)
b
Motor Function
Weakness of toe dorsiflexion is first motor dysfunction apparent
Motor impairment lags behind sensory impairment
Compare bilateral vigorous toe dorsiflexion
Less rapid and not as extensive on affected side = first sign of motor
impairment.
If no movement, categorize as Profound/Irreversible not Threatened
b
Foot examination
Marked blanching of foot when elevated and very slow capillary filling
when returned to horizontal
Foot becomes ruborous when dependent
Patient more comfortable when foot dependent, so foot is often edematous
if ischemia has been present for a few days
Gangrene is not present
Usually only seen with Chronic Critical Limb Ischemia (CLI)
Tenderness of calf muscles not uncommon (probably due to preference for
dependency, and resultant edema +/– lactic acid in the interstitial fluid).
Induration (muscle that is firm, but s till compressible and can contract) is
uncommon, but worrisome as it may be a sign of impending rigor (rock
hard, dead muscle tissue)
Rigor changes the category to irreversible and is probably best treated with
amputation
Induration prompts use of rapid clot-clearing techniques versus surgery
Careful monitoring during clot clearing is essential to detect evidence of
worsening ischemia and need to accelerate clot clearing
Careful monitoring following clot clearing is essential to detect local-
ized (compartment syndrome) or systemic revascularization syndrome
(outlined above)
284 T.O. McNamara and S.J. Muir
Doppler Findings
• No audible pulsatile flow in pedal arteries
• No ankle/brachial pressure ratio
• Audible pedal venous flow (with compression of foot)
Angiographic Findings
• Multi-vessel, multi-level occlusion
• Requirement for blood to traverse more than one collateral bed
• Usually in series
b
Occlusion of SFA and popliteal arteries with profunda collaterals to geniculate
collaterals to reconstitute flow in major distal vessel = trifurcation
b
Occlusion of common and external iliac arteries or one limb of aortobifemoral
bpg with collateral pathway via lumbars to internal iliac branches to common
femoral artery
• Occasionally in parallel
b
Origin occlusions of all three trifurcation arteries with collateral flow around
each
• Sometimes see a single level of acute occlusion, but obstruction of inflow to
collateral bed
Actions for Threatened
• Heparinize (initial and maintenance doses dependent on severity of sensorimotor
impairment)
b
Bolus of 3,000–5,000 units
b
Try to achieve a PTT of 80–100 sec.
b
Maintenance dose ~1,000 u/h I.V. to keep PTT 80–100 sec prior to lysis
Dependent upon degree of ischemia
If only hypesthesia→ aPTT of 60 sec probably sufficient
b
Cut back when lysis has been initiated
b
Therapeutic levels of heparin anticoagulation usually not deemed critical
during lysis
b
With urokinase aPTT of 60–80 sec is acceptable, but <45 sec with other lytics
b
Usually do not use heparin during tPA infusions and 150 units/h via sheath
when infusing either rPA or TNK
• Urgent angiography
Thrombolysis for Acute Lower Limb Ischemia 285
b
Probably best-performed ASAP, unless dramatic improvement following
heparin
• For Threatened the authors usually begin with continuous low-dose infusion (now
supplemented with ultrasound device – EKOS)
• Remember that the spectrum of ischemia within Threatened category extends
from minimal to marked sensorimotor impairment – treat accordingly
b
For minimal sensorimotor impairment, begin with low dose of lytic and re-
exam after overnight infusion.
b
Consider short-term high dose (4 h) if either sensory deficit is more than
hypesthesia or if there is some motor impairment.
b
High dose varies from 2 to 4 times low dose (given under Viable) depending
upon severity of ischemia, but prefer duration of <4 h followed by rean-
giogram at 4 h with intent to finish by aspirating any residual clot (Possis) or
just switch to low dose for overnight infusion if the clinical exam has improved
and no easy access to the interventional suite.
• Author prefers beginning with continuous infusion as it can be initiated with a
minimum of instrumentation, room time, sedation, and analgesia. Also, less risk
of embolization, hypertension, and hemoglobinuria that can follow use of the
POSSIS device
• Would use Angiojet to completely clear any residual clot at time of follow-up
angiogram as there is less clot which is more hydrated and easier to aspirate,
embolization less likely, and less significant.
• For worsening sensorimotor exam, no improvement with heparin, sluggish toe
movement, and/or sensation to only firm foot pressure, strongly consider initial
use of mechanical devices or other lytic adjuncts:
b
Consider Power Pulse Spray (PPS) versus just aspiration
PPS = loading dose of lytic into clot via Possis and then aspirate
PPS requires 20-min dwell time of drug in clot before aspiration
b
Bolus of abciximab into the clot (slowly deposit 0.25 mg/kg [diluted in 10
mL] as catheter is withdrawn from distal to proximal end of clot)
b
If Angiojet does not re-establish flow consider either bolus of abciximab and
initiate low-dose lysis versus no abciximab, but use of high-dose lytic × 4h
b
Consider infusions via EKOS catheter
• If ischemia worsens after above attempts (uncommon) consider surgery or repeat
effort with Possis.
b
Surgery is an excellent, but bigger, more stressful procedure and carries more
risk to these patients, who are likely to have associated coronary, carotid, and
lung disease.
b
Blaisdell’s review of the results of the emergency surgical treatment of 3,330
acutely ischemic limbs demonstrated a 27% mortality and a 14% amputation
rate
286 T.O. McNamara and S.J. Muir
• Our experience in treating these same types of occlusions with continuous-
infusion thrombolysis has yielded a 2% mortality and 5% amputation rate
• The additions of the potential accelerating effect of GP IIb/IIIa (abciximab, oth-
ers) and the AngioJet would be expected to at least maintain those improved
results
• The incidence of post-revascularization complications is less following lysis
b
Localized = compartment syndrome
b
Systemic syndrome = hypotension, arrhythmia, ARDS, ATN, death.
Irreversible/Profound Ischemia
• The clotting process is so extensive, collateral flow so reduced, and ischemic
changes so advanced that major amputation will be necessary if revascularization
is unsuccessful. The term Irreversible implies the inevitability of at least minor
tissue loss irrespective of successful revascularization (e.g., necrosis of toes or
forefoot) and neuropathy
Clinical/Physical Findings
• History
b
Same onset as other categories of ALLI
b
Pain is constant and severe unless sensation is absent
b
Pain is not relieved by dependency or walking
• Examination
b
Sensory function
Foot has profound sensory loss
Most clear-cut if anesthetic.
Proprioception gone
b
Motor function
Toe flexion is gone. Ankle movement is impaired or absent
b
Foot examination
COLD
Skin has fixed, marbled discoloration (purple and white)
Absent capillary refill
Calf muscle firmness with marked tenderness, unless limb is anesthetic
b
Muscle rigor (rock-hard dead muscle that cannot contract).
Thrombolysis for Acute Lower Limb Ischemia 287
Revascularizing this tissue carries a significant risk of death due to the
lethal systemic post-revascularization syndrome
b
The more proximal the leg involvement, the graver the prognosis
b
Purplish discoloration and coldness of thigh are associated with 50% mortality
in surgical series.
Doppler Findings
• No audible Doppler signals in either arteries or veins in the feet
• Absence of venous flow despite foot compression is an ominous sign
b
Last Doppler finding to go
b
Indicates thrombosis of the veins as well as arteries of the foot
Angiographic Findings
• Usually extensive occlusions involving both proximal and distal vessels without
reestablishment of flow into distal trifurcation and/or foot vessels.
• Profound/Irreversible = poorer results, higher risk; but lysis may be best
therapeutic alternative.
b
2 levels of occlusion and no trifurcation filling. Examples:
Femoropopliteal bypass graft + popliteal + (at least origins of) all trifurca-
tion arteries.
Common femoral artery occlusion (usually embolus) without demonstra-
ble filling of any distal vessels (rare).
Aortobifemoral + femoropopliteal bypass graft occlusions without demon-
strable filling of distal vessels (usually due to associated stenosis of
profunda femoris).
Popliteal artery occlusion + occlusion of all trifurcation arteries throughout
the calf; usually popliteal embolus with secondary propogation throughout
previously stenotic arteries (rare).
Action
• Systemic heparinization, including bolus.
• Do not lyse if calf muscles are not viable (rigid and non-functioning).
• These patients are considered poor candidates for lysis due to the long time
required to lyse what is generally a large clot volume and ischemia that is rapidly
advancing.
• If lysis attempted:
288 T.O. McNamara and S.J. Muir
b
Mechanical clot removal associated with bolus of GIIb/IIIa
b
Follow with continuous lytic infusion if flow can be restored through at least
one major trifurcation artery.
b
Consider a high dose of lytic for the first few hours after restoring flow
b
Systemically heparinize, but at low-end of therapeutic range if have given
abciximab, but upper end if not.
• Restoration of flow will flush intracellular contents (potassium, myoglobin), lac-
tic acid, fibrin–platelet aggregates, and pro-coagulants into systemic circulation
leading to Systemic Revascularization Syndrome.
b
Hypotension, arrhythmias, hypoxemia, ARDS, ATN.
b
High likelihood of death, myocardial infarction.
• For those candidates deemed to be acceptable surgical candidates, operative
removal of as much clot as possible, followed by intra-operative administration
of lytic or amputation, if unsuccessful
• Blaisdell recommended administration of high-dose heparin followed by either
delayed revascularization surgery or primary amputation depending upon the
evolution of the ischemia.
b
The goal was to minimize the loss of life associated with thromboembolec-
tomy of ALLI.
b
Improvements in anesthesia, cardiac care, and surgical management have
reduced that risk. Nonetheless, the Blaisdell approach should not to be
dismissed.
Key Points
• Combining angiographic, Doppler, and clinical findings enables one to
quite accurately assess how rapidly one needs to restore blood flow.
• The combination also guides one in recommending interventional versus
surgical treatments, as well as in deciding upon the intervention.
• For the most severely ischemic limbs there is the potential to rapidly restore
flow by combining lytic agents and abciximab as well as with the enhance-
ment provided by ultrasound (EKOS infusion catheter) and to effectively
aspirate with the Angiojet or other mechanical devices.
• Viable category of ischemia
b
Single segment of occlusion
b
Normal sensorimotor exam
b
~10% of ALLI
b
~100% likelihood of success
b
~0% likelihood of major amputation
b
~0% likelihood of death
Thrombolysis for Acute Lower Limb Ischemia 289
• Threatened category of ischemia
b
Two segments of occlusion (or equivalent) and >1 trifurcation patent
b
Impaired sensorimotor exam (minimal to marked)
b
~80% of ALLI.
b
~90% likelihood of success.
b
~5% likelihood of major amputation
b
~0% likelihood of death
• Irreversible/Profound category of ischemia.
b
Greater than two segments of occlusion and no trifurcation patent
throughout.
b
Anesthesia +/– Paraysis
b
Low success rate and high morbidity.
Suggested Reading
1. Ansel GM, George BS, Botti CF, McNamara TO, Jenkins JS, Ramee, SR Rosenfield K,
ANoethen, and Mehta T. Rheolytic thrombectomy in the management of limb ischemia:
30-day results from a multicenter registry. J Endovasc Ther 2002; 9(4): 395–402.
2. Bertele V, Roncaglioni MC, Pangrazzi J, Terzian E, Tognoni EG. Clinical outcome and its
predictors in 1560 patients with critical leg ischaemia. Chronic Critical Leg Ischaemia Group.
Eur J Vasc Endovasc Surg 1999;18: 401–410.
3. Callum K, Bradbury A. Clinical review ABC of arterial and venous disease. Br Med J 2000;
320: 764–767.
4. Davidian M, Powell A, Benenati J, Katzen B, Becker G, Zemel G. Initial results of reteplase in
the treatment of acute lower extremity arterial occlusions. J Vasc Interventional Radiol 2000;
11(3): 289–294.
5. Earnshaw J, Whitman B, Foy C . National Audit of Thrombolysis for Acute Leg Ischemia
(NATALI): clinical factors associated with early outcome. J Vasc Surg 2004; 39(5):
1018–1025.
6. Kasirajan K, Haskal Z, Ouriel K. The use of mechanical thrombectomy devices in the manage-
ment of acute peripheral arterial occlusive disease. J Vasc Interventional Radiol 2001; 12(4):
405–411.
7. Kessel D, Berridge D, Roberston I. Infusion techniques for peripheral arterial thrombolysis.
Cochrane Database Syst Rev 2004; 1: CD000985.
8. Kudo T, Chandra FA, Ahn SS. The effectiveness of percutaneous transluminal angioplasty for
the treatment of critical limb ischemia: a 10-year experience. J Vasc Surg 2005; 41: 423–435.
9. McNamara TO, Dong P, Chen J, Quinn B, Gomes A, Goodwin S, Aban K. Bleeding com-
plications associated with the use of rt-PA for peripheral arterial and venous thromboembolic
occlusions. Techniques in Vasc Interventional Radiol 2001; 4(2): 92–98.
10. McNamara TO, Gardner KR, Bomberger RA, Greaser LE. Clinical and angiographic selection
factors for thrombolysis as initial therapy for acute lower limb ischemia. J Vasc Interventional
Radiol 1995; Nov–Dec 6: 36–47.
11. McNamara TO, Fischer JR. Thrombolysis of peripheral arterial and graft occlusions:
improved results using high-dose urokinase. Am J Roentgenol 1985; 144(4): 769–775.
290 T.O. McNamara and S.J. Muir
12. McNamara TO. Thrombolysis treatment for acute lower limb ischemia. In Vascular Diseases:
Surgical and Interventional Therapy, edited by A. van Breda and D.E. Strandness 1994,
Churchill Livingstone, New York, 355–377.
13. McNamara, TO. Thrombolysis as an alternative initial therapy for the acutely ischemic lower
limb. Seminars Vasc Surg 1992; 5: 89–98.
14. Norgren L, Hiatt WR, Dormandy JA, Nehler MR, Harris KA, Fowkes FG. Inter-society
consensus for the management of peripheral arterial disease (TASC II). J Vasc Surg 2007;
45(Suppl S): S5–S67.
15. Slovet DP, Sullivan TM. Critical limb ischemia: Medical and surgical management. Vasc Med
2008; 13(3): 281–291.
Endovascular Treatment of Acute Stroke
Ali R. Zomorodi and Tony P. Smith
Introduction
• Stroke is the clinical situation that follows neurological cell death due to
decreased blood flow:
b
The area remaining where the cells are ischemic but not yet infarcted is called
the ischemic penumbra.
b
Penumbra is of variable size dependent on numerous factors:
Collateral blood flow
Perfusion pressure
Patient’s overall constitutional health
b
The restoration of blood flow to salvage this ischemic area is the goal in the
treatment of acute stroke.
• Therapy for acute stroke consists of supportive care, intravenous tissue
plasminogen-activating factor (tPA), endovascular measures, and some investiga-
tive approaches such as venous perfusion. Supportive care is involved regardless
of the therapy undertaken and becomes the mainstay of treatment when intra-
venous (IV) or intraarterial (IA) measures cannot be undertaken.
b
Intravenous tPA has United States Food and Drug Administration (FDA)
approval as a treatment for ischemic stoke in patients within3hofsymptom
onset.
• Endovascular treatment of stroke holds great promise for ameliorating one of the
leading causes of morbidity and mortality in the United States.
b
Requires an established stroke program with a multidisciplinary stroke team:
Abides by written protocols that are continuously reviewed and modified
in light of the ever changing clinical data
Scrupulous attention to institutional quality improvement and outcomes
tracking.
291
R.A. Morgan, E. Walser (eds.), Handbook of Angioplasty and Stenting Procedures,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-399-6_22,
C
Springer-Verlag London Limited 2010
292 A.R. Zomorodi and T.P. Smith
Clinical Features
• Estimated annual incidence of stroke is approximately 750,000 per year in the
United States.
• Stroke is the third leading cause of death and the leading cause of long-term
disability in the United States, with an estimated 60 deaths per 100,000 people.
• 83% of strokes are considered ischemic: due to large vessel thrombosis (31%),
embolism (32%), and small vessel thrombosis (20%). The remaining 17% are
hemorrhagic, of which approximately 10% are intracerebral hemorrhage and 7%
are subarachnoid hemorrhage.
• Endovascular treatment shows promise in treating large vessel thrombotic and
embolic ischemic stroke.
Diagnostic Evaluation
• The patient should be initially evaluated by the stroke team and the interventionist
is notified if the patient has an ischemic stroke within the appropriate treatment
window. Below is an outline of the key features of the diagnostic evaluation that
will impact the endovascular treatment.
History
• Time of symptom onset is critical. If not obtainable exactly from the patient or
family, the last time the patient was known to be normal is used.
• Recent history of trauma.
• Recent surgical procedures or lumbar puncture.
• Prior strokes.
• Seizures at time of stroke onset.
• Contrast allergy.
Physical Exam
• Determine vital signs and treat blood pressure to keep less than 180/100.
• Determine National Institute of Health Stroke Scale (NIHSS) presented at the
end of this chapter.
• Determine likely vascular territory and cause of stroke based on physical exam
findings (Table 1).