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2114 Part XII Hemostasis and Thrombosis

A B C

D E F

Fig. 143.1 A 67-YEAR-OLD MAN WITH A CHRONIC LEFT ILIAC ARTERY OCCLUSION AND A
RIGHT-TO-LEFT FEMORAL-FEMORAL ARTERIAL BYPASS PRESENTS WITH LEFT FOOT PAIN
AND PULSELESSNESS. (A) Digital subtraction arteriography reveals patency of the right iliac artery but
only a “stump” of the bypass graft is seen, consistent with graft thrombosis. (B) The lowermost aspect of the
right common femoral artery was accessed and a multi–side-hole infusion catheter was positioned across the
occluded graft. The radiopaque markers show the infusion zone. An infusion of recombinant tissue plasmino-
gen activator was given at 0.5 mg/hour through this catheter. The patient received heparin (500 units/hour)
through a peripheral intravenous catheter. (C) After 16 hours of thrombolysis, a repeat arteriogram reveals
successful thrombus removal with residual tight focal stenosis at the proximal graft anastomosis. (D) The
stenosis was subjected to angioplasty using a 6-mm balloon. (E) Repeat arteriogram shows improvement in
the stenosis, but small thrombi are evident within the graft. (F) After use of the AngioJet Rheolytic Throm-
bectomy System to aspirate residual thrombus, the graft is widely patent. Subsequent physical examination
revealed good pedal pulses and capillary refill, consistent with successful reperfusion of the limb.

Although there have been few changes to the basic CDT technique specialized catheters, known as percutaneous mechanical thrombectomy
over the past 25 years, there has been a switch from biologically (PMT) devices, have been developed. PMT is defined as the use of a
derived fibrinolytic drugs (streptokinase and urokinase) to recombi- percutaneous catheter-based device that contributes to thrombus
nant drugs that are less allergenic and have greater affinity for fibrin. removal via thrombus fragmentation, maceration, and/or aspiration.
In addition to the standard multi–side-hole infusion catheter, a Although originally developed to supplant thrombolytic drugs, until
specialized multi–side-hole infusion catheter (the Ekosonic Mach 4e recently, none of the available PMT devices has enabled safe, success-
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catheter, EKOS Corporation, WA, USA) that emits low-power ful clot removal when used as a stand-alone treatment. Consequently,
ultrasound energy to ostensibly loosen fibrin strands and permit more fibrinolytic drugs are used in conjunction with PMT, except in situ-
rapid intrathrombus drug dispersion is available. Although this ations where there are absolute contraindications to the use of fibri-
catheter also permits successful thrombolysis to be obtained, conclu- nolytic drugs and no other treatment options are available.
sive evidence that the addition of ultrasound energy improves patient Recently a new thrombectomy device (AngioVac, Angiodynamics)
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outcomes is lacking. 3,4 was introduced into some clinical practices. This device, which relies
upon creation of a bypass circuit to enable more robust suction
Variation on a Theme: Percutaneous Mechanical thrombectomy, may provide greater thromboaspiration capability
than previous devices. However, the device is somewhat inflexible and
Thrombectomy requires placement of two large access sheaths into the venous system.
Given the lack of prospective data on its use, at present this device
Hemorrhagic complications are the Achilles’ heel of currently avail- may be best targeted to urgent clinical problems for which there is
able thrombolytic agents. To reduce exposure to these drugs, no other solution (e.g., large thrombus in the suprarenal inferior vena