William R. Flinn

Six-year prospective multicenter randomized comparison of autologous saphenous vein and expanded polytetrafluoroethylene grafts in infrainguinal arterial reconstructions

Autologous saphenous vein (ASV) and polytetrafluoroethylene (PTFE) grafts were compared in 845 infrainguinal bypass operations, 485 to the popliteal artery and 360 to infrapopliteal arteries. Life-table primary patency rates for randomized PTFE grafts to the popliteal artery paralleled those for randomized ASV grafts to the same level for 2 years and then became significantly different (4-year patency rate of 68% +/- 8% [SE] for ASV vs. 47% +/- 9% for PTFE, p less than 0.025). Four-year patency differences for randomized above-knee grafts were not statistically significant (61% +/- 12% for ASV vs. 38% +/- 13% for PTFE, p greater than 0.25) but were for randomized below-knee grafts (76% +/- 9% for ASV vs. 54% +/- 11% for PTFE, p less than 0.05). Four-year limb salvage rates after bypasses to the popliteal artery to control critical ischemia did not differ for the two types of randomized grafts (75% +/- 10% for ASV vs. 70% +/- 10% for PTFE, p greater than 0.25). Although primary patency rates for randomized and obligatory PTFE grafts to the popliteal artery were significantly different (p less than 0.025), 4-year limb salvage rates were not (70% +/- 10% vs. 68% +/- 20%, p greater than 0.25). Primary patency rates at 4 years for infrapopliteal bypasses with randomized ASV were significantly better than those with randomized PTFE (49% +/- 10% vs. 12% +/- 7%, p less than 0.001). Limb salvage rates at 3 1/2 years for infrapopliteal bypasses with both randomized grafts (57% +/- 10% for ASV and 61% +/- 10% for PTFE) were better than those for obligatory infrapopliteal PTFE grafts (38% +/- 11%, p less than 0.01). These results fail to support the routine preferential use of PTFE grafts for either femoropopliteal or more distal bypasses. However, this graft may be used preferentially in selected poor-risk patients for femoropopliteal bypasses, particularly those that do not cross the knee. Although every effort should be made to use ASV for infrapopliteal bypasses, a PTFE distal bypass is a better option than a primary major amputation.

Collagen types and matrix protein content in human abdominal aortic aneurysms

Deficiencies of total collagen, type III collagen, and elastin have been proposed to explain aneurysm formation. Infrarenal aortas were collected from 19 patients (age 70 +/- 7 years) undergoing operative repair of abdominal aortic aneurysms (diameter 7 +/- 2 cm) and from 13 autopsies (age 63 +/- 17 years) of patients without aneurysm disease (controls). Wall thickness and collagen and elastin concentration were determined in full-thickness aorta. Collagen types I and III were measured after digestion with cyanogen bromide, which solubilized nearly 90% of total collagen for typing. Cyanogen bromide peptides were separated by sequential carboxymethylcellulose and agarose chromatography and quantified by peak area measurement with computerized image analysis. Histologic examination revealed prominent inflammatory cell infiltration and deficient, fragmented elastin in the aneurysms. Aortic wall thickness was similar in aneurysms and in control specimens. In the aneurysms, collagen was increased (37% +/- 16% vs 24% +/- 5%; p less than 0.05) and elastin was decreased (1% +/- 1% vs 12% +/- 7%; p less than 0.001), expressed as a percentage of delipidized, decalcified dry weight. Collagen type I accounted for 74% +/- 4% of aneurysm and 73% +/- 4% of control collagen solubilized for typing, and collagen type III accounted for 26% +/- 4% of aneurysm and 27% +/- 4% of control collagen solubilized for typing. Neither patients with a family history of aneurysms nor those without a history of aneurysms had collagen type III deficiency. Atherosclerotic abdominal aortic aneurysms are associated with an inflammatory process and may result from elastin degradation and not a deficiency of type III collagen.

Exercise rehabilitation improves functional outcomes and peripheral circulation in patients with intermittent claudication: a randomized controlled trial.

OBJECTIVE: To determine the effects of a 6‐month exercise program on ambulatory function, free‐living daily physical activity, peripheral circulation, and health‐related quality of life (QOL) in disabled older patients with intermittent claudication.

Blunt Aortic Injury

Blunt aortic injury occurs after sudden deceleration, and it is second only to head injury as the leading cause of death after automobile crashes. Helical computed tomography of the thorax is more ...

The efficacy of dextran 40 in preventing early postoperative thrombosis following difficult lower extremity bypass

In a randomized, multicenter trial the efficacy of intravenous dextran 40 (D-40; Rheomacrodex) in preventing early postoperative thrombosis was tested in the following difficult lower extremity bypasses: (1) femoropopliteal with poor runoff using autologous vein (AV), (2) femoropopliteal using grafts other than AV, (3) single or sequential bypasses to infrapopliteal arteries, and (4) the above-mentioned bypasses with adjunctive procedures that destroy adjacent endothelial surfaces (e.g., thrombectomy and endarterectomy). Five units of D-40 was administered to the experimental group at 75 to 100 ml/hr, two during and immediately after operation and one each 3 days postoperatively. Antiplatelet drugs were withheld until 1 week after surgery. The overall 1-week occlusion rate was 6.9% (5 of 73) with D-40 and 20.5% (17 of 83) for controls, which is statistically significant. Particularly significant was the difference in group 3: 0% (0 of 28) for D-40 and 27.8% (10 of 36) for controls. In the same time period there were no occlusions in group I and only one occlusion each with AV grafts in both D-40 and control groups, 2.6% (1 of 38). When grafts other than AV were used, the occlusion rate was significantly lower at 1 week for D-40, 11.4% (4 of 35), than controls, 35.6% (16 of 45). By 1 month the protective effect of D-40 was partially lost--15.3% (11 of 72) for D-40 and 20.7% (17 of 82) for controls (no statistical significance). Use of antiplatelet drugs during this period had no discernible effect.

Upper extremity arterial injury in athletes

Between 1983 and 1986, 23 athletes were evaluated for arm and hand complaints. Eleven players had symptoms of thoracic outlet compression. Severe arm fatigue (eight patients) and finger ischemia (three patients) were the presenting symptoms. In the remaining 12 athletes, symptoms of hand ischemia were predominant. Noninvasive testing with Doppler ultrasonography and duplex scanning (positional testing and finger systolic pressure recording) and cold immersion were used to aid in diagnosis. In the 11 athletes with thoracic outlet compression, arteriography confirmed the finding with compression of the subclavian artery in five, the axillary artery in one, both subclavian and axillary arteries in two, posterior humeral circumflex artery in one, and subclavian aneurysm in two. Compression of the suprascapular artery was identified in four, the subscapular artery in two, and the posterior humeral circumflex artery in one. Thrombosis of a first basemans ulnar artery and occlusion of the palmar arch in a frisbee player were documented by arteriography. Decompression of the thoracic outlet consisted of anterior scalenectomy in five, pectoralis minor muscle division in one, and resection of both muscles in two. Removal of cervical rib with interposed vein graft was performed in the two players with arterial aneurysm. Hand ischemia in the remaining athletes was treated conservatively with Dextran-heparin infusion for acute ischemia. Repeat noninvasive study of all players demonstrated absence of compression in their playing position, and all have resumed their playing careers. Hand ischemia in athletes can be evaluated noninvasively and treated conservatively. Resection of hypertrophied muscles to decompress the thoracic outlet together with release of branch artery compression in selected athletes promotes perfusion to arm and shoulder muscles and helps to avoid the catastrophic complication of repetitive trauma leading to sudden arterial thrombosis.

Improved long-term patency of infragenicular polytetrafluoroethylene grafts ☆ ☆☆

This article reviews late graft patency and the incidence of postoperative complications in 75 infragenicular polytetrafluoroethylene bypass grafts (20 posterior tibial, 26 anterior tibial, and 29 peroneal). All patients received a heparin infusion after operation and were switched to warfarin before discharge to maintain coagulation parameters (prothrombin time and partial thromboplastin time) approximately twice that of control subjects. Primary procedures were done in 14 patients (19%), and the remaining patients had one or more previous procedures. Ninety-seven percent of patients had limb-threatening ischemia. Graft patency was confirmed by interval examinations and Doppler ankle pressure measurements. The mean follow-up was 36 months, and long-term graft patency (4 years) was determined by life-table analysis. The 2-year cumulative patency rate for this group was 45% and the 4-year patency rate was 37%. The latter is significantly better than the patency rates of 12% reported for similar untreated randomized grafts. Anticoagulation was subtherapeutic in 15 patients at the time of graft thrombosis, and if these were excluded, the 2- and 4-year patency rates were 58% and 50%, respectively. Hematomas requiring drainage occurred in 10 patients (13.3%) and six patients (8%) developed wound infections, but graft infection occurred in only two patients. Two patients (2.6%) developed late bleeding complications necessitating cessation of the warfarin. There was one fatal perioperative myocardial infarction (1.3%) and four late deaths, none of which were related to the warfarin therapy. Although the incidence of postoperative hematoma and wound infection was increased, late complications occurred infrequently.(ABSTRACT TRUNCATED AT 250 WORDS)

Deep vein thrombosis in spinal cord injury: effect of prophylaxis with calf compression, aspirin, and dipyridamole.

Deep Vein thrombosis is very common in spinal cord injury patients, and a randomized study comparing the prophylactic use of external pneumatic calf compression, aspirin and dipyridamole has been carried out

The reoperative potential of infrainguinal bypass: Long-term limb and patient survival***

The present study reviews the fate of patients undergoing reoperation after failure of infrainguinal bypass grafts. During a 10-year period, 202 patients with failed distal bypass grafts had 389 infrainguinal reoperative procedures, an average of 1.9 reoperations per patient. Including the initial procedure and subsequent reoperations, a total of 591 operations were performed in this group. Secondary bypass was performed in 101 patients, a tertiary procedure in 51, a fourth bypass in 30, and more than four operations were required in 20 patients. Reoperation was performed to treat severe ischemia (rest pain, ulceration, or gangrene) in 377 of 389 cases (97%). Repetitive bypass was performed with autogenous vein in 21 cases (7.4%), composite grafts in 16 patients (5.6%), and polytetrafluoroethylene in 247 cases (87%). The remaining 105 reoperations were thrombectomy in 77 cases, thrombectomy plus distal angioplasty in 20 cases, and profundaplasty in eight cases. The distal anastomosis was to the popliteal artery in 14% of reoperative cases and to the tibial or peroneal artery in 59%. Mean follow-up for all patients was 70 months. Four operative deaths occurred in 389 reoperations (1.0%), and there were 35 late deaths. The cumulative life-table 5-year survival rate for all patients was 80%. The operative morbidity rate was 12.3%, including wound infection in 3.1% and hematoma in 6.4%. Sixty-seven cases required major amputation, below-knee in 48 (72%) and above-knee in 19 (28%). The 5-year limb salvage rate was 59%. Cumulative graft patency was 37% at 5 years. The 80% 5-year survival rate may reflect aggressive management of associated carotid and coronary artery disease. The demonstrated long survival indicates that recurrent ischemia after distal bypass failure requires attention. In this study, re-operation provided long-term limb salvage in most cases without significant compromise in patient safety or amputation level if amputation was required.

Sequential changes in coagulation and platelet function following femorotibial bypass

Twenty-four patients who received no antiplatelet medications and underwent femorotibial bypass grafting (nine vein, 12 polytetrafluoroethylene [PTFE], and three composite PTFE-vein) had serial measurements taken of their platelet function and coagulation. The concentration of collagen required to produce half-maximal platelet aggregation (Kd), the platelet aggregation ratio, antithrombin III, factor VIII-related antigen, and fibrinolytic activity (platelet-rich plasma) was measured preoperatively and 3 and 7 days after surgery. Before surgery eight patients exhibited an increase of platelet reactivity to collagen. Following femorotibial bypass grafting, the mean preoperative Kd of 0.52 +/- 0.37 microgram/ml fell to 0.34 +/- 0.35 microgram/ml on the third postoperative day (P less than 0.001) and returned to 0.41 +/- 0.72 microgram/ml on day 7. Factor VIII-related antigen increased from a mean preoperative value of 248 +/- 29% of normal activity to a mean of 360 +/- 96% on postoperative day 3 (p less than 0.01) and further increased to 428 +/- 78% on day 7 (p less than 0.01). Fourteen patients had antithrombin III measurements taken, and their levels also fell on the third postoperative day (110 +/- 5.7% to 71 +/- 6.5%; p less than 0.001). No significant changes in fibrinolytic activity were noted. Persistent platelet reactivity was found in seven patients beyond the seventh postoperative day. After administration of 325 mg of aspirin, the abnormal platelet reactivity ceased. Increased platelet reactivity to collagen, factor VIII-related antigen, and a decrease in the antithrombin III level are indicative of a hypercoagulable state in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)