Realistic expectations for pedal bypass grafts in patients with end-stage renal disease.

PURPOSE: Limb-threatening ischemia in patients with end-stage renal disease (ESRD) represents a challenging clinical problem. Multiple series have shown the inferior limb salvage rate for femoropopliteal or femorotibial bypass grafts in this group. This outcome study is restricted to those patients with ESRD who require pedal bypass grafts for attempted limb salvage. METHODS: Between December 1, 1990, and December 31, 1997, 34 patients with ESRD underwent pedal bypass grafting on 41 limbs. This review explores the patient and bypass graft outcomes and their relationships to typical risk factors. RESULTS: The average age in the study was 64 years (range, 39 to 85 years). Twenty patients (59%) were men, 31 (91%) had diabetes, 32 (94%) were hypertensive, and 28 (82%) had coronary artery disease, but only 10 patients (29%) were smokers. All the patients were undergoing dialysis except 2 patients with functioning renal transplants. All bypass grafting procedures were performed for limb salvage. The follow-up periods ranged from 1 to 84 months (average, 13.5 months). With life-table analysis, the cumulative assisted primary patency rate was 62% at 1 year and 62% at 2 years. The limb salvage rate was 56% and 50% at 1 and 2 years, respectively. All the patients who were seen with heel gangrene had early limb loss or died. Seven of the 16 amputations (44%) were performed despite patent bypass grafts. Ten of the 16 amputations (63%) occurred within 3 months of the surgery. The survival rate was 64% at 1 year and 52% at 2 years. After the bypass graft procedure, the mean ankle brachial index and the toe pressure rose from 0.48 to 1.05 and 18 to 86, respectively. CONCLUSION: Modest success can be expected with pedal bypass grafts in patients with ESRD, with most failures occurring in the first 3 months. Limb salvage rates lag behind graft patency rates because of progressive necrosis despite a hemodynamically functioning bypass graft. Heel gangrene is a strong predictor for a negative outcome. Lastly, overall patient survival rates are poor but comparable with the rates of other patients with ESRD.

Limb loss after lower extremity bypass.

BACKGROUND: Infrainguinal bypass now has a limb salvage rate approaching 90% at 10 years. This study helps elucidate the causes of limb loss despite bypass surgery. METHODS: A retrospective chart review of all patients undergoing a major lower extremity amputation after attempted bypass surgery. RESULTS: Between July 1987 and January 1997, 67 major amputations (52 below knee, 15 above knee) followed infrainguinal bypass for limb salvage in 64 patients. Of these patients, 53 (83%) were diabetic and 10 (16%) were on dialysis. The etiology of limb loss included thrombosed bypass (n = 33, 49%), lack of limb salvage despite patent bypass (n = 23, 34%), intraoperative bypass failure (n = 6, 9%), and exposed/infected bypass (n = 5, 8%). The 23 patients with patent grafts required amputations because of hindfoot necrosis (n = 6), persistent forefoot necrosis (n = 6), acute diabetic foot infection (n = 6), and various other reasons (n = 5). Using life-table analysis, survival for the whole group was 56% at 12 months and 17% at 48 months. Patients with limb loss despite a patent bypass fared the worst with survival of 21% at 2 years. CONCLUSIONS: Bypass thrombosis caused half of the amputations after limb salvage surgery. A patent bypass was functioning at the time of amputation in another third. Survival after failure of limb salvage was abysmal, especially in patients with patent bypasses.

Biologic characteristics of long-term autogenous vein grafts: a dynamic evolution.

PURPOSE: The venous conduit as an arterial substitute has dynamic biologic properties that affect its durability. This study evaluated the morphologic and physiologic characteristics of 72 lower extremity vein grafts functioning at 4.5 to 21.6 years (median 6.6 years). METHODS: The entire graft was imaged with use of color duplex ultrasonography and then classified as normal (class I), abnormal but not graft-threatening (class II), or abnormal and graft-threatening (class III) for the proximal, middle, and distal thirds. Thirty-one grafts (43%) were classified as normal, whereas 41 (57%) were classified as abnormal, with 58 class II and 15 class III segments. RESULTS: Three types of abnormalities were found by duplex imaging: nonstenotic wall plaques, discrete stenoses, and aneurysmal dilation. Aneurysms developed in five of seven grafts that had required thrombectomy in the distant past (mean of 40 months). There were 70 postoperative revisions in 38 limbs (53%). In 23 (60%) the conduit was revised, in 11 (29%) the revisions corrected progression of native artery atherosclerotic disease, and in 4 (11%) both types of revisions were required. Eleven grafts were revised in the first 30 days to correct technical errors. Eighteen limbs were revised between 1 and 24 months, with 12 (67%) of the revisions correcting stenotic lesions in the conduit or at one of the anastomoses. After 24 months 12 (67%) of 18 limbs were revised to correct progression of occlusive disease in the inflow or outflow vessels. At the time of this study 18 (67%) of the 27 conduits revised for intrinsic lesions were abnormal by color duplex imaging, and they harbored 12 (80%) of the 15-graft-threatening lesions. CONCLUSIONS: Autogenous vein remains the most durable arterial conduit, but vigilant surveillance is essential because the atherosclerotic environment continually produces lesions that may imperil the longevity of the graft.

Wound complications of the in situ saphenous vein bypass technique.

Wound complications after in situ saphenous vein bypass occur frequently, lengthen hospitalization, and threaten graft viability. From May 1981 to March 1991, 117 consecutive male patients underwent 126 in situ operations: 45 (36%) femoropopliteal, 75 (59%) femorotibial, and 6 (5%) grafts to the dorsal pedal artery for gangrene or ulcer (n = 69), rest pain (n = 54), or claudication (n = 3). Wound complications developed in 55 grafts (44%): erythema developed in 11, but they healed primarily, 19 had skin edge necrosis or localized lymph leaks, 12 had necrosis or infection into the subcutaneous tissue without danger to the graft, and invasive infections that threatened the graft developed in 13. Risk factors for a subsequent wound infection included the development of a lymph leak (p less than or equal to 0.05) and early postoperative graft revision for thrombosis, wound hematoma, retained valve or arteriovenous fistula (p less than or equal to 0.05). The mean time to appearance of a graft-threatening wound infection was 31 days, and 10 of 13 were located in the distal limb. Twelve of the 13 deep infections required operative debridement, and seven required a flap or split thickness skin graft for coverage. Gram-negative as well as gram-positive infections responded equally well. No grafts were lost, and no deaths occurred. Despite the high incidence of wound complications, an aggressive therapy regimen permitted universal graft salvage.

The role of duplex scanning versus angiography in predicting outcome after balloon angioplasty in the femoropopliteal artery.

Duplex-derived velocity measurements were used to assess the hemodynamics of 64 femoropopliteal arterial sites in 59 patients after angiographically successful percutaneous transluminal balloon angioplasty. With use of angiography as the gold standard, percutaneous transluminal balloon angioplasty was judged to be successful if (1) evidence existed of a "split" caused by intimal dissection and splitting of atherosclerotic plaque; and (2) no significant diameter-reducing residual stenosis was observed at the percutaneous transluminal balloon angioplasty site. At 1 month, 55 limbs (86%) were hemodynamically and clinically improved by SVS/ISCVS clinical criteria for chronic limb ischemia. Of the 55 percutaneous transluminal balloon angioplasty sites, duplex scanning had identified 40 (63%) sites with a less than 50% diameter-reducing stenosis and 15 (27%) sites with a greater than 50% diameter-reducing stenosis within a week after percutaneous transluminal balloon angioplasty. Independent review of the 55 angiograms taken after percutaneous transluminal balloon angioplasty identified 39 sites (71%) with a split and 16 sites (29%) without. By life-table analysis, a greater than 50% diameter-reducing stenosis predicted a worse clinical outcome (15% at 1 year) compared with the presence of a less than 50% diameter-reducing stenosis (84% at 1 year) (p less than 0.001; log rank test). The presence or absence of an angiographic split was not a predictive factor of percutaneous transluminal balloon angioplasty outcome (split, 61% at 1 year; no split, 62% at 1 year) (p = 0.832; log rank test). The detection of a functional residual stenosis by duplex scanning did not correlate with angiographic appearance, but was predictive of clinical failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of stress thallium imaging to stratify cardiac risk in patients undergoing vascular surgery.

Reduction of the cardiac morbidity associated with major vascular procedures requires identification of high risk patients prior to operation. This retrospective study reviews the records of 126 consecutive patients who underwent 141 major vascular procedures to determine the accuracy of preoperative clinical, laboratory (ECG), and cardiac function testing (stress thallium-201 scintigraphy, left ventricular ejection fraction scan) in predicting perioperative cardiac complications. An abnormality on oral dipyridamole or treadmill thallium imaging was demonstrated prior to 71 (61%) of 116 procedures and included 20 fixed and 51 reperfusion (reversible) defects. No patient died within 30 days of operation, but 11 minor (ventricular arrhythmia) and 15 major (myocardial infarction, ischemic congestive heart failure) cardiac complications occurred. A reperfusion defect on stress thallium imaging accurately (94% sensitivity, 56% specificity, 98% negative predictive value) identified high-risk patients while accepted clinical rating systems (Goldman, Cooperman, Eagle) and preoperative level of left ventricular ejection fraction were less predictive of adverse cardiac events. Patients without myocardium at risk by coronary angiography, but a reperfusion defect on stress thallium imaging were found to be at high risk for a cardiac complication. The study data support the use of stress thallium imaging to stratify cardiac risk prior to major arterial surgery.

Percutaneous intraarterial thrombolysis in the treatment of thrombosis of lower extremity arterial reconstructions.

Vascular grafts may be salvaged with thrombolytic therapy after acute occlusion as an alternative to balloon catheter thrombectomy. From October 1987 to May 1990, 15 arterial bypasses to the lower extremity (infrainguinal saphenous vein [n = 7] or expanded polytetrafluoroethylene [n = 6], and Dacron aortofemoral bifurcation graft limbs [n = 2]) were treated for 30 occulsions with intraarterial urokinase (390,000 IU to 5,808,000 IU) infused from 3 to 40 hours. The origins of 15 graft occlusions were morphologic defects (intimal hyperplasia with anastomotic or conduit stricture), pseudoaneurysm, or progression of disease distal to the graft. Two occlusions were attributed to coagulation disorders. A cause could not be identified for 13 occlusions. Patency was initially restored to all grafts with use of thrombolytic therapy, however, adjunctive surgical thrombectomy to remove persistent thrombus from the graft or outflow vessels was required after six thrombolytic infusions. One graft in the series could not be salvaged leading to below-knee amputation. Graft defects were corrected by balloon angioplasty (n = 7) or surgical revision of the conduit (n = 8). Five significant hemorrhagic complications occurred from the catheter insertion site requiring four emergent surgical procedures and resulting in the death of a fifth patient from a myocardial infarction. This technique allows chemical thrombectomy of branch arteries distal to the graft and inaccessible to a balloon embolectomy catheter, and permits diagnosis of abnormal graft morphology that may be the cause of the graft occlusion. Graft reocclusion can be expected if technical defects in the arterial reconstruction are not revised or hypercoagulable states are not treated.