Multicenter trial of the wallstent in the iliac and femoral arteries.

PURPOSE: To report the results of the FDA phase II, multicenter trial of the Wallstent in the iliac and femoral arteries. PATIENTS AND METHODS: Two hundred twenty-five patients entered the trial. Stents were placed in the iliac system in 140 patients and in the femoral system in 90 (five patients required both iliac and femoral stents). Clinical patency was measured over 2 years by means of life-table analysis with use of clinical and hemodynamic data and the Rutherford scale. Angiographic patency was measured at 6 months. RESULTS: In the iliac system the primary clinical patency was 81% at 1 year and was 71% at 2 years. The secondary clinical patency was 91% and 86%, respectively. The 6-month angiographic patency was 93%. In the femoral system the primary clinical patency was 61% at 1 year and 49% at 2 years. The secondary patency was 84% and 72%, respectively. The 6-month angiographic patency was 80%. CONCLUSIONS: The results are similar to those with the Palmaz stent in the iliac system and with angioplasty alone in the iliac and femoral systems.

New techniques for percutaneous renal revascularization: atherectomy and stenting.

All current techniques for PTRA carry the risk of re-stenosis due to intimal hyperplasia and associated complications. More data are now available to better determine the best candidates for PTRA or surgical revascularization. Great progress has been made with the introduction of renal artery stenting. I believe that this technique, when adequately sized and positioned, will give the best long-term results. Further randomized trials are needed to prove that this technique is superior to PTRA.

The incidence of deep venous thrombosis in patients undergoing abdominal aortic aneurysm resection.

PURPOSE: Fifty consecutive patients undergoing abdominal aortic aneurysm resection were studied prospectively for the presence of deep venous thrombosis (DVT) after surgery. METHODS: Bilateral venography was performed 5 days after surgery in all patients. There were 42 men and 8 women, with a mean age of 70 years (range 60 to 83 years). No patients received DVT prophylaxis before surgery. RESULTS: Nine (18%) of 50 patients had a venogram positive for acute DVT. Nine (21%) of 42 men and none of eight women had DVT. Six patients had DVT in the left leg and three patients in the right leg. No patients had symptoms to suggest DVT. Seven (78%) of the nine patients with DVT had thrombi in the calf veins and two patients (22%) had thrombi in the more proximal venous segments, representing 14% and 4% of the entire series, respectively. No clinically evident pulmonary emboli were observed. CONCLUSIONS: Eighteen percent of 50 consecutive patients undergoing abdominal aortic aneurysm resection had DVT. Because of this high incidence, a study should be undertaken to determine whether DVT prophylaxis can lower the incidence of DVT after abdominal aortic aneurysm resection.

A prospective, randomized, blinded, and placebo-controlled trial of intraoperative intra-arterial urokinase infusion during lower extremity revascularization. Regional and systemic effects.

OBJECTIVE: This study was designed to evaluate the safety and regional and systemic effects of three doses of urokinase (UK) infused into the distal arterial circulation during routine operative lower extremity revascularization. METHODS: One hundred thirty-four patients were prospectively randomized to receive one of three bolus doses of UK (125,000, 250,000, or 500,000 U) or placebo (saline) infused into the distal circulation before lower extremity bypass for chronic limb ischemia. Regional (femoral vein) and systemic (arm) blood was sampled before drug infusion, prereperfusion, and postreperfusion, and systemic blood samples were obtained 2 hours postreperfusion. Assays evaluated plasma levels of fibrinogen, fibrin(ogen) degradation products (FDP), fibrin breakdown products (D-dimer and fragment B-beta 15-42), and plasminogen. Patients were monitored for clinically evident bleeding complications. The Wilcoxon rank-sum test was used to compare different drug doses with the placebo. RESULTS: Intraoperative bolus UK infusions produced no significant fibrinogen breakdown compared with placebo. There was a dose-related decline in plasminogen levels, which became significant at a dose of 500,000 U of UK (p < 0.001). There were dose-related increases in plasma FDP, which became significant at dose of 250,000 and 500,000 U (p < or = 0.005), and in plasma D-dimer, which were significant at all UK doses (p < 0.001). The changes in plasma fibrinogen and markers of fibrin breakdown were similar in the regional and systemic circulations. There was no increase in operative blood loss, blood replaced, or wound hematoma formation. There was an unexplained increased mortality in the placebo group (21.1% vs. 2.0%, p = 0.033). CONCLUSIONS: Intraoperative bolus UK infusion is safe, with no significant fibrinogen depletion or increased operative blood loss or wound hematoma formation. Dose-related plasminogen activation resulted in significant breakdown in cross-linked fibrin in the distal circulation. Intraoperative bolus UK infusion may be valuable as an adjunct in patients with chronic occlusive disease who are undergoing revascularization. Detailed randomized studies are indicated to establish clinical efficacy.

Deep venous thrombosis and pulmonary embolism. The importance of heightened awareness.

Left untreated, deep venous thrombosis and pulmonary embolism have a high rate of mortality and long-term morbidity. Physicians therefore must maintain a high index of suspicion for these conditions. Accurate diagnosis is facilitated by knowing the most common sites of thrombus formation, the likelihood of propagation, which patients are at greatest risk, signs and symptoms, and which tests to order. Prompt administration of anticoagulants and, in some cases, thrombolytic agents can minimize the consequences of these diseases. Interruption of the inferior vena cava, thrombectomy, and thromboembolectomy are other treatment options.

Nonsurgical restoration of pulsatile arterial flow.

Percutaneous transluminal angioplasty is an established method of revascularization in a variety of arterial stenotic conditions. When applied to specific morphologic and clinical indications, it can be very effective. It appears to be the procedure of choice for focal stenotic lesions of the iliac and femoropopliteal system. Its role in infrapopliteal atherosclerotic disease is less certain, but more optimistic, with recent reports. New methods for preventing restenosis and abrupt closure are currently being developed, and they appear to be promising as adjunctive therapy with mechanical catheter-directed intervention. The future of these adjunctive agents will likely improve the outcome and reduce the immediate failure rates of angioplasty. Other modalities, including thermal laser angioplasty and atherectomy, also appear to have a promising future. These methods, coupled with better endoluminal guidance, such as ultrasound, will help guide the interventional procedure more precisely and hopefully broaden the application and improve the outcome.

Relative cost-effectiveness of urokinase versus streptokinase in the treatment of peripheral vascular disease.

A retrospective case control study of 271 patients with peripheral arterial occlusion (PAO) who were treated with urokinase (UK) or streptokinase (SK) at two clinical centers, Alexandria Hospital and the Cleveland Clinic, was performed. The primary objective was to evaluate the relative cost-effectiveness of thrombolytic therapy with SK or UK in the treatment of PAO. A secondary objective was to identify factors to which any major differences in cost-effectiveness between these two agents could be attributed. All available patients hospitalized at the two centers for PAO who underwent treatment with UK or SK from 1979 to 1987 were included. Therapeutic success was defined as complete clot lysis or partial clot lysis judged to be of clinical benefit by the attending physician, with no major bleeding or other serious complication such as renal insufficiency or death. Success rates with UK were higher than those with SK at both centers. The advantage with UK could not be explained by baseline patient characteristics. A cost-effectiveness ratio--dollars expended on medical care for up to 2 days after infusion per therapeutic success--was calculated for each of the treatments. Overall, at Alexandria Hospital, $10,700 was expended per therapeutic success with UK therapy compared with $14,500 for successful SK therapy. At the Cleveland Clinic, differences were more pronounced, with $15,000 expended per therapeutic success for UK treatment and $46,400 per success for SK treatment. Support for preference of UK therapy is provided by the consistency of results in favor of UK cost-effectiveness for subgroups of patients that were determined according to site of occlusion and type of therapy following lysis. The cost-effectiveness of UK was not dependent on the definition of patient costs associated with PAO.

Safety and efficacy of thrombolytic therapy for superior vena cava syndrome.

The experience at the Cleveland Clinic from 1982 to 1990 using thrombolytic therapy for superior vena cava (SVC) syndrome was retrospectively reviewed. Sixteen patients, 11 of whom had indwelling central venous catheters, were treated with either urokinase (n = 11) or streptokinase (n = 5). Either urokinase (4,400 U/kg bolus followed by 4,400 U/kg/h) or streptokinase (250,000 U bolus followed by 100,000 U/h) was used, and venograms were performed before and after. Overall, 56 percent of patients had complete clot lysis and relief of symptoms. Thrombolytic therapy was effective in eight (73 percent) of 11 patients receiving urokinase and one (20 percent) of five patients receiving streptokinase. Of those with a central venous catheter, eight (73 percent) of 11 patients were successfully lysed, whereas only one (20 percent) of five patients was successfully lysed if no catheter was present. If thrombolytic therapy was performed less than or equal to five days of symptom onset, seven (88 percent) of eight patients were successful, if thrombolytic therapy was performed greater than five days after symptom onset, two (25 percent) of eight patients were successful. Symptoms were relieved and the catheter was preserved in patients in whom thrombolytic therapy was effective. Factors predicting success were as follows: (1) the use of urokinase compared with streptokinase; (2) the presence of a central venous catheter; and (3) a duration of symptoms less than or equal to five days.

The changing clinical spectrum of thromboangiitis obliterans (Buerger's disease).

Between 1970 and 1987, 112 patients were diagnosed as having thromboangiitis obliterans (TAO). The age was 42 +/- 11 years (mean +/- SD; range, 20-75 years); 23% were women, and 7% were more than 60 years old when they were first diagnosed. Ischemic ulcerations were present in 85 (76%) patients: 24 (28%) patients with upper-extremity, 39 (46%) patients with lower-extremity, and 22 (26%) patients with both upper- and lower-extremity lesions. Ninety-one (81%) patients had rest pain, 49 (44%) patients had Raynaud's phenomenon, and 43 (38%) patients had superficial thrombophlebitis. We were able to follow up 89 of the 112 (79%) patients for 1-460 months (mean follow-up time, 91.6 +/- 84 months). Sixty-five (73%) patients had no amputations, while 24 (27%) had one or more of the following amputations: finger, six (15%) patients; toe, 13 (33%) patients; transmetatarsal, four (10%) patients; below knee, 14 (36%) patients; and above knee, two (5%) patients. Forty-three (48%) patients stopped smoking for a mean of 80 +/- 105 months (median, 46.5 months; range, 1-420 months), and only two (5%) patients had amputations after they stopped smoking, while 22 (42%) patients had amputations while continuing to smoke (p less than 0.0001). The spectrum of patients with TAO is changing in that the male-to-female ratio is decreasing (3:1), more older patients are being diagnosed, and upper-extremity involvement is commonly present. In the 48% of patients who stopped smoking, amputations and continued disease activity were uncommon.

Fibrinogen A alpha and gamma-chain dimers as potential differential indicators of atherosclerotic and thrombotic vascular disease.

Cross-linked fibrin(ogen) dimers are known to be elevated in the plasma of subjects with occlusive vascular disease, and are thought to be fibrin dimers. Immunoelectrophoretic analyses of the dimers, however, indicate that (1) they are predominantly fibrinogen rather than fibrin dimers, and (2) they contain cross-linked A alpha-chains (A alpha-dyads) instead of the gamma-chain dyads that are rapidly formed by factor XIII during blood coagulation. Furthermore, the mobilities of the A alpha-dyads differ from the cross-linked alpha-chain products that accompany the gamma-chain cross-linking by factor XIII. Instead, the mobilities coincide with the distinct A alpha-dyads that are produced by tissue transglutaminase, an intracellular enzyme not normally present in plasma. The intimal fibrinogen deposits in atherosclerotic aortas also possess fibrinopeptide A and cross-linked A alpha-chains. Thus, both the plasma fibrinogen dimers and the intimal fibrinogen deposits appear to derive from the action of released tissue transglutaminase more so than factor XIII. It is proposed that, in the absence of other indications of cytolytic processes, the levels of A alpha-dyads in plasma reflect ongoing cellular injury accompanying atherogenesis. The extent to which gamma-dyads accompany the A alpha-dyads may signal progression of the disease to advanced stages in which ulcerations and occlusive lesions trigger thrombotic complications.

Transluminal atherectomy for occlusive peripheral vascular disease.

The failure of balloon angioplasty to provide a durable result has led to the development of other methods of catheter-associated interventional therapy. In this study, 112 patients with superficial femoral artery stenosis or occlusion were treated with percutaneous atherectomy. Patients were considered to have a simple lesion if the occluded or stenotic arterial segment was less than 5 cm, and a complex lesion if the length of the occluded segment was greater than 5 cm. All atherectomies were performed in the superficial femoral and popliteal arteries; urokinase thrombolysis was used in conjunction with atherectomy in 16 patients. Atherectomy was considered successful if there was less than 20% residual stenosis determined by arteriography. Initial atherectomy results (30 day patency) were 100% successful in the group with a simple lesion and 93% successful in the group with a complex lesion. At a mean follow-up period of 12 months (range 5 to 24), there was a continued patency rate of 93% and 86%, respectively, in the simple and complex groups. In the patients who had restenosis, all pathologic specimens obtained during the second procedure demonstrated myointimal hyperplasia and organized thrombus. Eight major complications (7.1%) occurred, including one fatal myocardial infarction. The complication rate was 3.5% in the simple group and 8.3% in the complex group. With the exception of the myocardial infarction, all complications were associated with catheter entry site hematomas. Femoropopliteal atherectomy has a high rate of success and low morbidity and mortality for both simple and complex lesions and is a viable and competitive alternative therapy for patients with severe peripheral vascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of atherosclerotic renal artery stenosis in patients with atherosclerosis elsewhere.

PURPOSE: To determine the prevalence of atherosclerotic renal artery stenosis in patients who have atherosclerosis elsewhere but lack the usual clinical clues to suggest renal artery stenosis. PATIENTS AND METHODS: The arteriograms and charts of 395 consecutive patients were prospectively reviewed by a member of the Vascular Medicine Department and a member of the Radiology Department. These patients underwent arteriography as part of the routine evaluation for abdominal aortic aneurysm (109 patients), aorto-occlusive disease (21 patients), lower-extremity occlusive disease (189 patients), and suspected renal artery stenosis (76 patients). Patients in the first three groups did not have the usual clues that suggest renal artery stenosis. RESULTS: There was greater than 50% renal artery stenosis in 41 patients (38%) with abdominal aortic aneurysm, seven patients (33%) with aorto-occlusive disease, 74 patients (39%) with lower-extremity occlusive disease, and 53 patients (70%) with suspected renal artery stenosis. The prevalence of renal artery stenosis was similar in diabetic and nondiabetic patients with abdominal aortic aneurysm, aorto-occlusive disease, or suspected renal artery stenosis, but higher in diabetics with lower-extremity occlusive disease (50%) compared to nondiabetics with lower-extremity occlusive disease (33%) (p = 0.022). High-grade bilateral disease was present in approximately 13% of patients with abdominal aortic aneurysm or lower-extremity occlusive disease, and totally occluded renal arteries occurred in 5% of the patients in these groups. There was an association between increasing degree of renal artery stenosis and the presence of hypertension and worsening of renal function. CONCLUSION: Patients with atherosclerosis elsewhere, especially abdominal aortic aneurysm, aorto-occlusive disease, or lower-extremity occlusive disease, have a high prevalence of significant renal artery stenosis even in the absence of the usual clues to suspect renal artery stenosis. Diabetic patients have a similar prevalence as nondiabetic patients. This information may have important therapeutic implications in patients being considered for vascular surgery.

Electrophoretic characterizations of cross-linked fibrinogen derivatives in blood and vascular tissue by zonal immobilization on glyoxyl agarose.

Direct immunoprobing of electrophoregrams of plasma and intimal protein on glyoxyl agarose and composite-gels with polyacrylamide have uncovered novel modes of cross-linking of fibrinogen that differ from those previously characterized. These modes of cross-linking involve the A alpha-chains of fibrinogen and hybrid cross-linking of alpha- and gamma-chains.

Preoperative evaluation and management of coronary and carotid artery occlusive disease in patients with abdominal aortic aneurysms.

Aortic aneurysms rarely exist without systemic manifestations of atherosclerosis beyond the confines of the aneurysm. Preoperative evaluation of coronary and carotid disease is critical in the management of patients with abdominal aortic aneurysms in the perioperative period as well as in the long term.

Thrombolytic therapy for renal artery occlusions: a preliminary report.

Percutaneous transluminal angioplasty and renal artery revascularization have been successful in controlling blood pressure and preserving renal function in patients with atherosclerotic renal artery stenosis. In addition, thrombolysis appears promising for treatment of patients with total occlusion of renal artery bypass grafts. More experience will be necessary to define its role in native renal artery occlusions. The authors describe successful thrombolysis in two of three patients given thrombolytic therapy for total occlusion of renal arteries.

Thrombolytic therapy. A review (Part 1 of 2).

Despite the discovery of thrombolytic agents more than 50 years ago, only recently has major interest become evident in their use to treat myocardial infarction, venous thromboembolism, and peripheral arterial disease. Use of thrombolytic drugs may result in myocardial and limb salvage as well as improved survival rates and quality of life for patients affected by potentially devastating vascular disease. We review historical highlights, outstanding studies, and important aspects of thrombolytic therapy, emphasizing its use in peripheral vascular disease.