Long-Term Outcomes of Catheter-Directed Thrombolysis for Acute Lower Extremity Occlusions of Native Arteries and Prosthetic Bypass Grafts

Abstract

Background: Catheter-directed thrombolysis is a well-accepted treatment for acute lower extremity occlusions of native arteries and bypass grafts. Several variables that affect outcomes of thrombolysis have been identified. The hypothesis of this study was that the long-term outcome after catheter-directed thrombolysis would be better for acute lower extremity occlusions of native arteries compared with prosthetic bypass grafts.

Methods: This observational study retrospectively analyzed 159 consecutive patients (114 men), median age, 65 years (range 57-73 years), with 89 native artery (56%), and 70 prosthetic bypass graft (44%) occlusions of the lower extremity. All patients were treated with catheter-directed thrombolysis between 2006 and 2009 in 2 vascular referral centers in the Netherlands. The severity of ischemia was Rutherford class I (52%), class IIa (27%), class IIb (12%) and unknown (9%) in native arteries and class I (64%), class IIa (19%), class IIb (1%), and unknown (16%) in bypass grafts. Median (range) duration of symptoms before the start of thrombolysis was 3.5 (1-14) days in native arteries and 3 (1-9) days in bypass grafts. All patients were treated with a continuous dosage of urokinase (100,000 IU/h). Amputation-free survival was estimated by conduit type using the Kaplan-Meier method and compared using the log-rank test. Univariate and multivariate analyses were performed using a Cox proportional hazards model.

Results: Complete (>95%) lysis was achieved in 69% of native arteries and bypass grafts (P = 1.00). Major hemorrhagic complications occurred in 12% (4% hemorrhagic strokes, of which 2% were fatal) of native arteries and in 7% (0% hemorrhagic stroke) of bypass grafts (P = 0.28). The 30-day mortality rate was 6% in native arteries and 1% in bypass grafts (P = 0.17), and the 30-day amputation rate was 10% in native arteries and 13% in bypass grafts (P = 0.45). Mean follow-up was 27 ± 19 months. Amputation-free survival at 1 year was 76% for native arteries and 78% for bypass grafts and at 5 years was 65% for native arteries and 51% for bypass grafts (P = 0.32). Multivariate analysis showed 2 negative predictors for amputation-free survival: age >65 years and cerebrovascular disease. Conduit type was not an independent predictor for amputation-free survival (P = 0.78).

Conclusions: Despite initial promising results, long-term follow-up of catheter-directed thrombolysis for acute lower extremity occlusions showed a disappointing amputation-free survival. In multivariate analysis, no significant differences in amputation-free survival between native arteries and prosthetic bypass grafts were determined.