Joseph R. Schneider

Variables that affect the expansion rate and outcome of small abdominal aortic aneurysms

Seventy-three patients with small (less than 6 cm in diameter) abdominal aortic aneurysms (AAAs) were selected for nonoperative management and followed up with sequential ultrasound size measurements. Fifty-four men and 19 women, 51 to 89 years of age (mean 70 years), had an initial mean AAA size of 4.1 cm (anteroposterior) x 4.3 cm (lateral) diameter, with a calculated elliptic cross-sectional area of 14.3 cm2. After a mean of 37 months of follow-up, AAA area increased at a mean rate of 20% per year (3 cm2 yr; 0.4 to 0.5 cm/yr diameter). Expansion rate was not affected by initial aneurysm size. During follow-up, only 3 patients (4%) required urgent operation (1 died), 26 patients (36%) died of non-AAA causes, and 26 patients (36%) underwent elective AAA repair because of progressive size increase (1 died). Elective operations were performed at the rate of 10% per year, when mean AAA size had increased to 22 cm2 (5.1 cm in diameter). Multiple regression analysis of clinical parameters available at presentation indicated that subsequent elective AAA repair was predicted by younger age at diagnosis and larger initial aneurysm size. As anticipated, patients who underwent surgery had more rapid aneurysm expansion (5.3 cm2/yr) compared with patients who did not undergo surgery (1.6 cm2/yr; p less than 0.05). This difference was caused by more rapid expansion during later follow-up intervals among patients selected for operation and was not predicted by the change in aneurysm size observed during initial ultrasonographic follow-up. Final aneurysm size was predicted by initial size, duration of follow-up, and both systolic and diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical treatment of infrainguinal arterial occlusive disease in women

PURPOSE This study reviewed the outcome of 131 women who underwent infrainguinal bypass in 150 limbs from 1984 to 1991 for limb-threatening ischemia (95%) or disabling claudication (5%). METHODS These women were compared with 209 men who underwent infrainguinal arterial reconstruction of 231 lower extremities for limb threat (89%) or claudication (11%) during the same interval. On average, women were 3 years older than men (mean age 72 vs 69 years, p < 0.005) but were less frequently cigarette smokers (56% women, 68% men, p < 0.05). Fifty-two percent of women had diabetes and 67% had hypertension, similar to the male patients. Infrainguinal disease distribution necessitated bypass to the above-knee popliteal artery in 10%, to the below-knee popliteal artery in 25%, and to the tibial or pedal arteries in 65% of women, comparable to the disease distribution in men. Autogenous vein grafts were performed in 90% of both groups. RESULTS Early postoperative (30-day) mortality was 4% for women and 2% for men (not significant). Life-table survival after 3 years, however, was only 54% in women, compared with 72% in men (p < 0.05). Multivariate analysis indicated that diabetes increased the mortality rate 2.5-fold in women, which was not true in men. Three-year life-table survival of women with diabetes was only 39%, compared with 78% in women without diabetes (p < 0.001). Primary graft patency in women was 59% at 1 year and 54% at 3 years, significantly less than the 73% and 70% graft patency rates observed in men (p < 0.005). Secondary graft patency improved in women to 75% and 69% after 1 and 3 years, but this was still significantly less than the secondary patency rates of 89% and 86% observed in men (p < 0.001). Multivariate analysis indicated that female sex decreased secondary graft patency 2.4-fold and was the only variable associated with graft failure. Cumulative 3-year limb salvage in women was 82%, not statistically different than the 89% limb salvage rate observed in men. CONCLUSIONS Women and men requiring arterial reconstruction for infrainguinal occlusive disease had comparable operative mortality and limb salvage rates, but long-term survival and graft patency were significantly reduced in women. Our results indicate that sex substantially influences the outcome of patients after infrainguinal bypass.

Pedal bypass versus tibial bypass with autogenous vein: A comparison of outcome and hemodynamic results

PURPOSE Autogenous vein grafts to infrapopliteal arteries performed for chronic limb-threatening ischemia between 1984 and 1991 were reviewed to determine whether bypasses to pedal arteries produce results comparable to those obtained after supramalleolar tibial or peroneal bypasses. METHODS Pedal bypass (dorsal pedal, n = 41; below-ankle posterior tibial, n = 12) was performed only if a suitable tibial target artery was not available. These grafts were compared with tibial (including peroneal) bypass grafts (n = 203). All grafts were placed for rest pain (23%) or established tissue loss (77%). RESULTS Patients requiring pedal bypass were more likely to have diabetes and congestive heart failure but less likely to have a history of smoking. Age, gender, previous myocardial infarction, and other comorbidities were similar in the two groups. Operative mortality rates (30 days) were higher for pedal than tibial bypasses (9% vs 2%; p = 0.021), possibly reflecting the higher prevalence of diabetes, congestive heart failure, and more advanced systemic atherosclerosis associated with severe tibial artery disease. Most grafts were in situ saphenous vein (70% pedal vs 79% tibial). Life-table 3-year primary graft patency (58% pedal vs 61% tibial), secondary patency (82% pedal vs 79% tibial), limb salvage (92% pedal vs 87% tibial), and patient survival (61% pedal vs 64% tibial) were comparable in the two groups. Improved assisted primary patency and secondary patency rates in both groups were primarily a result of revision of graft-threatening lesions detected with noninvasive graft surveillance before thrombosis. Mean postoperative ankle/brachial index was similar for pedal and tibial bypasses, whereas mean duplex-estimated graft flow was less for pedal grafts (88 +/- 10 ml/min vs 129 +/- 6 ml/min; p = 0.002). Pedal bypass represented 21% of our experience with infrapopliteal vein grafts for chronic limb-threatening ischemia and was required more frequently in diabetic patients. Operative mortality rates were higher in patients undergoing pedal bypass, suggesting that aggressive preoperative diagnostic studies and perioperative monitoring may be appropriate for this group. Long-term survival was similar. CONCLUSION We conclude that autogenous vein pedal bypass grafts provide hemodynamic results and limb salvage rates comparable to more proximal tibial bypasses in properly selected patients.

A blinded comparison of angiography, angioscopy, and duplex scanning in the intraoperative evaluation of in situ saphenous vein bypass grafts

Angiography, angioscopy, and duplex scanning have each been advocated for intraoperative assessment of in situ saphenous vein grafts. We compared these three modalities during operation in a prospective, blinded study during the construction of 20 femoral-infragenicular in situ saphenous vein grafts. Each modality was used and interpreted by a surgeon blinded to the results of the other studies. Abnormalities requiring intervention were defined as (1) patent vein side branches, (2) residual valve cusps, and (3) anastomotic stenoses greater than 30%. Criteria, specific to the modality, corresponding to each category were prospectively defined. Fourteen residual valve cusps, 49 patent vein branches, and 6 anastomotic stenoses were suggested by at least one modality. Nine residual valve cusps, 32 patent vein branches, and no anastomotic stenoses were actually found (and corrected) by direct inspection. Sensitivity of detecting patent side branches for angiography, duplex scanning, and angioscopy was 44%, 12%, and 66%, respectively. Both angiography and angioscopy were significantly more sensitive than duplex scanning for detection of unligated side branches (p less than 0.01). Sensitivity of detecting residual valve cusps was 22% (angiography), 11% (duplex scanning), and 100% (angioscopy). Angioscopy was significantly more sensitive than either duplex scanning or angiography in detection of residual valve cusps (p less than 0.01). Since no anastomotic stenoses were confirmed, the false-positive rates for stenosis detection were 20% for angiography, 10% for duplex scanning, and 0% for angioscopy. Time requirement was 17 to 20 minutes and did not differ among the three modalities. No stenosis or arteriovenous fistula has been detected in any graft by postoperative duplex surveillance (mean, 10-month follow-up).(ABSTRACT TRUNCATED AT 250 WORDS)

The natural history of superficial femoral artery stenoses

Since the natural history of specific superficial femoral artery stenoses is not known, we examined progression rates of superficial femoral artery stenoses in 45 lower extremities found when arteriograms were obtained of 38 patients for symptomatic atherosclerotic disease in the opposite leg or abdomen. These initial superficial femoral artery arteriograms were compared with later arteriograms in 25 limbs, duplex scans in 27 limbs, and both modalities in 7 limbs. After a mean interval of 37 months, most superficial femoral artery stenoses (72%) did not progress. However, 12 superficial femoral artery stenoses progressed (28%; mean follow-up, 37 months, including 7 that occluded (17%). Superficial femoral artery stenoses progressed among patients who complained of symptom progression at a rate faster than that among asymptomatic patients (15.6%/year vs 3%/year; p = 0.006). Superficial femoral artery lesions also progressed more rapidly among patients whose contralateral superficial femoral artery was occluded (10%/year vs 1.6%/year; p = 0.04). By multivariate regression analysis, symptom progression and smoking history were predictive of superficial femoral artery stenosis progression. In the seven patients whose superficial femoral artery stenoses progressed to occlusion, the average rate of stenosis progression was 12%/year (maximum predicted rate, 30% per year by 95% confidence limit). These results indicate that superficial femoral artery stenoses usually progress with synchronous symptomatic deterioration. Other than symptom progression, only cumulative smoking history and contralateral superficial femoral artery occlusion could be associated with superficial femoral artery stenosis progression in this small series.(ABSTRACT TRUNCATED AT 250 WORDS)

Axillofemoral bypass: Outcome and hemodynamic results in high-risk patients*

Aortobifemoral bypass (AoFB) is the preferred method to provide lower extremity inflow. To determine whether axillofemoral bypass (AxFB) is an acceptable alternative for high-risk patients, we reviewed our results with these two operations. Between 1985 and 1990, 29 axillobifemoral and 5 axillounifemoral bypass procedures were performed preferentially because of severe associated medical illness in patients with severe aortoiliac occlusive disease. During the same interval, 107 patients received an AoFB for pure aortoiliac occlusive disease. Nearly all patients having AxFB and AoFB were heavy smokers, and the two groups had similar rates of hypertension and angina. However, other major risk factors were more frequently found in patients undergoing AxFB. Limb-threatening ischemia was more frequent and femoral artery occlusive disease was more severe in patients having AxFB. Anastomosis to the deep femoral arteries and concomitant infrainguinal bypass were more likely to be required in patients who had AxFB. Life-table patient survival at 3 years was 35% for AxFB versus 91% for AoFB (p less than 0.001). Primary patency at 3 years was 63% for AxFB versus 85% for AoFB (p = 0.032). Secondary patency was 74% for AxFB versus 94% for AoFB (p less than 0.001). However, all revised grafts in both groups were patent at 36 months, and only one revised AxFB graft was an ultimate failure. Limb salvage at 3 years was 76% for AxFB versus 97% for AoFB (p = 0.065). Nineteen of the 22 patients with AxFB who died during follow-up died with patent grafts. Hemodynamic performance of AxFB and AoFB were compared. Mean preoperative ankle-brachial index was higher in AoFB (0.50) than AxFB (0.38, p less than 0.001), but postoperative ankle-brachial index was much higher after AoFB (0.83) than AxFB (0.57, p less than 0.001). Even after adjustment for severity of outflow disease, postoperative ankle-brachial index was much better after AoFB than AxFB. Axillofemoral bypass was performed in older higher risk patients with more severe ischemia than those in the AoFB group. Hemodynamic performance was inferior and graft failure more common after AxFB. However, AxFB provided limb salvage in all but 2 of 22 patients who have died, and no survivor has had amputation because of graft failure. Axillofemoral bypass is an acceptable but hemodynamically inferior alternative to AoFB in properly selected high-risk patients with critical lower extremity ischemia who would likely not tolerate the more durable AoFB.

Intragraft drug infusion as an adjunct to balloon catheter thrombectomy for salvage of thrombosed infragenicular vein grafts: A preliminary report

Early infragenicular vein graft thrombosis is associated with poor secondary patency, particularly when no correctable defect is identified. We have attempted to improve patency of thrombosed vein grafts by direct infusion of vasodilator and anticoagulant drugs after surgical thrombectomy. Among 212 infragenicular vein grafts, 16 (7.5%) required thrombectomy within 30 days of surgery (14 in situ saphenous vein, 1 composite vein, and 1 cephalic vein graft). Causes for failure were corrected in four (graft twist, intimal tear, suture failure, and external compression), resulting in prolonged patency. No cause for failure was apparent in the 12 remaining grafts after balloon catheter thrombectomy and arteriography. Two of these grafts occluded within 10 days despite multiple attempts at vein patch angioplasty, distal graft extension, and repeat thrombectomy with systemic anticoagulation. In the remaining 10 grafts, a small polyethylene catheter was placed in a proximal vein branch for direct intragraft drug infusion. Heparin (10 units/min) and nitroglycerin (50 micrograms/min) were the agents infused most frequently, for a mean duration of 52 hours after thrombectomy. Of these 10 infused grafts, 8 remained patent during a mean 17-month follow-up (range, 6 to 38 months). This was accomplished despite previous and repeated failures of thrombectomy and systemic anticoagulation in seven of these eight grafts. Two infused grafts rethrombosed within 30 days of infusion, resulting in amputation. No catheter-related complications occurred. Increased thrombogenicity, intimal injury, and spasm after balloon catheter thrombectomy may contribute to vein graft rethrombosis in the absence of technical defects. Direct intragraft infusion of nitroglycerin and heparin contributed to prolonged salvage of 80% of thrombosed vein grafts in this preliminary experience.

Pelvic blood flow following aortobifemoral bypass with proximal end-to-side anastomosis.

Nine patients with end-to-side aortobifemoral bypasses were studied in the first year after surgery using color duplex imaging to determine the source of pelvic blood flow. No patient had clinical evidence of postoperative pelvic ischemia. Six of nine patients were found to have occluded distal aortas by duplex studies performed at a mean of 4.4 months postoperatively (range 0.8–8.2 months). Of those six patients, postoperative duplex examination demonstrated two with no common or external iliac blood flow, two with bilateral retrograde external iliac flow, and two with unilateral retrograde external iliac flow. Of the three patients with patent distal aortas, two had no demonstrable external iliac blood flow, while the third had continued antegrade flow through one external iliac and retrograde flow through the other. Analysis of preoperative arteriograms failed to reveal accurate predictors of postoperative distal aortic patency or retrograde iliac blood flow. Despite the preoperative assumption that prograde common iliac artery blood was required to prevent pelvic ischemia, distal aortic patency was maintained in only three of nine patients. In the six patients with prograde iliac blood flow, no ischemic symptoms were present, including two patients with complete absence of antegrade aortic or retrograde external iliac blood flow. Our observations indicate that assumptions which underlie the decision to perform end-to-side aortic anastomoses are often not borne out in the months following aortobifemoral bypass.