Faculty Bibliography

In the management of limb-threatening infrainguinal arteriosclerosis, the short vein graft is a feature of distal-origin bypass procedures from the superficial femoral and popliteal arteries to more distal arteries. These procedures, which can only be performed in selected patients, have patency rates equivalent to those of comparable bypasses from the common femoral artery. Other advantages include the increased availability of the shorter vein graft segment that is required. Two newer operations that use short vein grafts are tibio-tibial bypasses and bypasses to isolated segments of infrapopliteal arteries. The authors' initial experience with these two procedures includes encouraging patency and limb salvage rates for periods up to 2 years in patients for whom there was no other therapeutic option short of amputation

Eight patients with severe pedal ischemia in the presence of palpable foot pulses are described. All had atherosclerosis, and seven patients also had diabetes. There were two anatomic patterns of disease, including supramalleolar obstruction with reconstitution of pulsatile flow in three patients and segmental occlusion of the pedal vessels in five. All patients underwent arterial reconstructive surgery. Patency was sustained in six patients, with limb salvage in five and below-knee amputation in one patient for persistent necrosis and infection of an open amputation. Of the two eventual bypass failures, a transmetatarsal amputation continued to heal in one patient, and the other required amputation below the knee. Palpable pedal pulses and satisfactory ankle/brachial indexes did not rule out the presence of surgically correctable distal arterial occlusive disease. Therefore arteriography is indicated in any patient with persistent forefoot ischemia that fails to respond to conservative measures. The safety and patency of the distal reconstructive procedures performed in this series suggest that salvage of weight-bearing tissue and rapid healing, as well as limb salvage, are legitimate indications for revascularization

From January 1, 1974 to December 31, 1989, we treated 2829 patients with critical lower-extremity ischemia. In the last 5 years, 13% of patients had therapeutically significant stenoses or occlusions above and below the groin, while 35% had them at two or three levels below the inguinal ligament. Unobstructed arterial flow to the distal half of the thigh was present in 26% of patients, and 16% had unobstructed flow to the upper third of the leg with occlusions of all three leg arteries distal to this point and reconstitution of some patent named artery in the lower leg or foot. In the last 2 years, 99% of all patients with a threatened limb and without severe organic mental syndrome or midfoot gangrene were amenable to revascularization by percutaneous transluminal angioplasty (PTA), arterial bypass, or a combination of the two, although some distal arteries used for bypass insertion were heavily diseased or isolated segments without an intact plantar arch. Limb salvage was achieved and maintained in more than 90% of recent patient cohorts, with a mean procedural mortality rate of 3.3%. Recent strategies that contributed to these results include (1) distal origin short vein grafts from the below-knee popliteal or tibial arteries to an ankle or foot artery (291 cases); (2) combined PTA and bypass (245 cases); (3) more distal PTA of popliteal and tibial artery stenoses (233 cases); (4) use of in situ or ectopic reversed autogenous vein for infrapopliteal bypasses, even when vein diameter was 3 to 4 mm; (5) composite-sequential femoropopliteal-distal (PTFE/vein) bypasses; (6) reintervention when a procedure thrombosed (637 cases) or was threatened by a hemodynamically significant inflow, outflow, or graft lesion (failing graft, 252 cases); (7) frequent follow-up to detect threatening lesions before graft thrombosis occurred and to permit correction of lesions by PTA (58%) or simple reoperation; and (8) unusual approaches to all infrainguinal arteries to facilitate secondary operations, despite scarring and infection. Primary major amputation rates decreased from 41% to 5% and total amputation rates decreased from 49% to 14%. Aggressive policies to save threatened limbs thus are supported

With multilevel arteriosclerosis, some patients undergoing infrainguinal bypass grafting will develop femoral/brachial pressure gradients only after the bypass is performed. We therefore evaluated arteriographically alternate inflow sites and measured the femoral/brachial pressure gradients before and after placement of 87 femorofemoral and 510 femoropopliteal/infrapopliteal bypasses. No prebypass femoral/brachial pressure gradients were present with and without intraarterial papaverine. However, femoral/branchial pressure gradients greater than or equal to 15 mm Hg were observed after the bypass placement in 16 femorofemoral patients and 43 femoropopliteal/infrapopliteal patients. Gradients averaged 28 +/- 8 (SD) (range, 15 to 50) mm Hg. The post femorofemoral bypass gradients were treated by immediate supplementary inflow extension to the aorta (three patients) or an axillary artery (three patients); by postoperative iliac percutaneous transluminal angioplasty (four patients) or by no treatment (six patients with femoral/brachial pressure gradients of 15 to 35 [23 +/- 5] mm Hg). The 43 postfemoropopliteal/infrapopliteal bypass gradients were treated by immediate supplementary inflow extension to the contralateral femoral artery (15 patients), the aorta (8 patients), or an axillary artery (3 patients); by postoperative iliac percutaneous transluminal angioplasty (5 patients) or by no treatment (12 patients with femoral/brachial pressure gradients of 15 to 30 [21 +/- 4] mm Hg). No thrombosis occurred in the 10 femorofemoral bypasses with postbypass femoral/brachial pressure gradients that were treated. One of the six femorofemoral patients with untreated gradients required a subsequent aortic extension, and one thrombosed after 2 years. Of the 12 untreated patients with femoropopliteal/infrapopliteal bypasses one graft occluded early, and two late failures occurred 12 and 18 months later.(ABSTRACT TRUNCATED AT 250 WORDS)

To determine systemic and local risk factors that contribute to limb loss despite a patent infra-inguinal bypass graft and how to prevent it, we reviewed 987 patients who underwent infra-inguinal bypasses at our institution. Seventy-five (7.6%) patent grafts failed to achieve a healed foot despite exhaustive attempts to do so and these patients underwent major amputation either above the knee (AKA) or below the knee (BKA). In 525 femoro-popliteal bypasses, there were 38 major amputations (29 BKA; 9 AKA) with a patent graft; in 462 femoro-distal bypasses, there were 37 amputations (22 BKA; 15 AKA) with a patent graft. The remaining 912 patients with limb salvage as well as all the patients with limb loss were evaluated with regard to systemic risk factors, quality of the run-off from the popliteal artery, continuity of the tibial artery into the arch as demonstrated on arteriography, the haemodynamic improvement obtained postoperatively, and the presence and extent of necrosis in the foot. The presence of diabetes, extensive pedal necrosis and advanced infection predispose to limb loss despite a patent lower extremity bypass graft. Patients who lost their limbs despite a functioning bypass to an isolated popliteal segment had significantly less pronounced haemodynamic improvement postoperatively. An early graft extension to a reconstituted tibial or peroneal artery or a direct bypass to a distal tibial or peroneal artery may reduce the incidence of limb loss in this setting. When a patent bypass to an isolated tibial or peroneal artery segment failed to relieve foot ischaemia, limb salvage was achieved by a distal extension to plantar arteries

Bilateral 6 mm PTFE grafts were placed from the external iliac artery to the femoral artery with ligation of the intervening segment of the iliofemoral artery in 14 dogs. An arteriovenous fistula was constructed at the distal anastomosis on one randomly selected side in each animal while the contralateral graft served as a control. Graft follow-up ranged between 8 and 12 months in all animals. Serial arteriography was performed to confirm graft and fistula patency and demonstrated persistence of antegrade flow into the arterial tree distal to all patent bypasses. Femoral intraarterial pressures distal to patent grafts were identical on both sides in each animal throughout the study. Cumulative life-table patency rates showed higher patency for the arteriovenous fistula bypasses than the control grafts at all time intervals: 71% vs. 57% at 3 months, 48% vs. 25% at 6 months, and 40% vs. 22% at 12 months, respectively. This is the first controlled study that provides experimental evidence suggesting that these bypasses may produce increased patency of prosthetic arterial grafts and lends support to their use in a clinical, prospective, randomized study

Detection of failing arterial reconstructions requires intensive surveillance by frequent physical examination and noninvasive laboratory testing. However, many grafts fail during the intervals between these examinations. For this reason, we have developed an implantable miniaturized piezoelectric flow detection device whose function can be monitored externally by radiotransmission across the skin. Sensors were constructed from ultrathin polyvinylidene fluoride (PVF2) with piezoelectric activity and attached with silicone fixative to 6-mm polytetrafluoroethylene grafts. Ten of these grafts were placed in mongrel dogs as iliofemoral bypasses. Real time data were acquired from the sensors at a rate of 200 Hz, using a DATAQ A/D data acquisition board and CODAS data acquisition software, while simultaneous blood flow (using an electromagnetic flowmeter) and intraluminal pressure were processed by using separate channels of the same data acquisition board. The data were stored on computer storage media and analyzed by the ASYST software, which allows simultaneous signal curves to be compared using regression analysis. In the resting state, the mean blood flow was 123 +/- 16 mL and the mean intraluminal pressure was 124/78 mm Hg, and there was perfect correlation between the PVF2 sensor and the flowmeter and between the sensor and the intraluminal pressure (correlation coefficient, r greater than or equal to 0.99 and r greater than or equal to 0.93, respectively). A tourniquet was applied to the iliac artery proximal to the graft to reduce the flow to approximately half of the resting state (mean flow after tourniquet: 66 +/- 6 mL/minute). Signal tracings from the three sources showed a remarkable similarity with a very high correlation coefficient (r greater than or equal to 0.99 between sensor and flowmeter and r greater than or equal to 0.92 between sensor and the pressure signal). These preliminary results show that the sensors made from low-profile and low-mass PVF2 material have the potential of being implanted around grafts for long-term, continuous monitoring of graft function. Further studies involving long-term implantation to assess the effect of tissue ingrowth and loss of compliance are necessary before this device can be used clinically

A dual laser system capable of distinguishing atherosclerotic plaque from components of normal arterial wall was used to deliver laser energy to cut a channel through occluded vessels. This system was used to facilitate balloon angioplasty of short (3-17 cm) total occlusions of the superficial femoral or popliteal arteries in 17 patients. In 10 patients the occluding lesion was traversed by the laser wire and patency was effectively restored by balloon angioplasty. Satisfactory luminal patency has persisted for 2 to 12 months (mean 6 months) in 9 cases; the lesion in the tenth patient restenosed at 3 months. The laser procedure was unsuccessful in all 3 cases with occlusions over 10 cm and in 4 others. There were no clinically important complications. This experience suggests that most patients who presently require interventional treatment can be managed by standard angioplasty methods and/or require a bypass operation. The 'Smart' laser is safe and effective short-term in facilitating angioplasty in some patients in whom standard angioplasty techniques are not feasible. The implications of these findings are discussed

Routine arteriography of the axillary, subclavian, and innominate arteries before axillofemoral bypass surgery has not been advocated because of the presumed rarity of stenosis of these inflow vessels. However, we have noted in this patient population with extensive atherosclerosis that inflow disease can cause axillofemoral graft failure despite normal preoperative clinical and noninvasive parameters. We prospectively determined the incidence of unsuspected inflow stenosis with arteriography in 40 consecutive candidates for primary (28) or secondary (12) axillofemoral bypass surgery. A new arteriographic technique with a single translumbar puncture was developed to safely and clearly visualize the potential inflow and outflow tracts. Ten of the 40 patients (25%) exhibited inflow stenosis greater than 50% of luminal diameter (unilateral in eight patients and bilateral in two patients). Seven were on the left side (five subclavian, two axillary) and five were on the right side (three subclavian, one axillary, one innominate). In eight of the 40 patients (20%) the stenotic inflow lesion was ipsilateral to the ischemic leg and therefore proximal to the preferred inflow site of an axillofemoral bypass. Upper extremity arterial pressure measurements suggested potential inflow artery stenosis in only three of the 12 (25%) instances. These findings show that equal arterial pressures in the upper extremities do not ensure adequate inflow for an axillofemoral graft. Routine arteriographic assessment of inflow intacts is recommended before axillofemoral bypass surgery

In the last 10 years we have treated 28 patients with 33 groin infections involving a common femoral artery anastomosis of prosthetic arterial grafts (2 aortic Dacron grafts, 31 peripheral polytetrafluoroethylene grafts). Management included complete graft preservation for patent infected grafts (11 cases), subtotal excision of occluded infected grafts leaving an oversewn 2 to 3 mm graft remnant attached to a patent artery critical for limb survival (16 cases), and total graft excision with arterial oversewing or ligation for anastomotic bleeding (6 cases). Essential treatment adjuncts included (1) radical operative wound debridement, and (2) secondary revascularization by means of bypasses tunneled via lateral uninfected routes, and unusual approaches to uninvolved patent outflow arteries (i.e., the distal superficial or deep femoral or popliteal arteries) after isolation of the infected wound. Follow-up averaged 3 years (1 to 10 years). This plan of treatment resulted in an 11% (3/28) hospital mortality and an amputation rate of 13% (4/30 threatened limbs). Of the 25 survivors with 30 infected groin grafts, 87% (26) of the wounds healed uneventfully by secondary intention within 1 to 8 weeks (mean, 4 weeks) and have remained healed. One infected groin wound did not heal and required delayed total graft excision. Three patients had late anastomotic disruption with hemorrhage at 8 months, 2 years, and 4 years after initial treatment. This selected use of complete or partial graft preservation and other essential treatment adjuncts are proposed as a safer, easier method for managing infected prosthetic arterial grafts in the groin