A single-centre protocol using low-dose urokinase for catheter-directed thrombolysis in the treatment of acute lower limb ischaemia.

Objectives: Catheter-directed thrombolysis is one of the main treatments for acute limb ischaemia. Urokinase is still a widely used thrombolytic drug in some regions. However, there needs to be a clear consensus on the protocol of continuous catheter-directed thrombolysis using urokinase for acute lower limb ischaemia.

Methods: A single-centre protocol of continuous catheter-directed thrombolysis with low-dose urokinase (20,000 IU/hour) lasting 48-72 h for acute lower limb ischaemia was proposed based on our previous experiences. A retrospective study from June 2016 to December 2020 was conducted to evaluate the efficacy and safety of this protocol. The target lesion revascularisation, amputation and death were also monitored during follow-up. The Kaplan-Meier estimator was used for the subgroup analysis, and univariate and multivariate Cox regression analysis was applied to identify risk factors for reinterventions and death.

Results: 90 lower limbs were involved, including 51 Rutherford Grade I, 35 Grade IIa and four Grade IIb. During a 60.8-h thrombolysis, 86 cases (95.5%) were considered effective according to the angiogram. No major bleeding complication occurred during thrombolysis, and one amputation occurred after. Freedom from target lesion revascularisation, amputation and death were 75.6%, 94.4% and 91.1% during a mean 27.5-month follow-up, respectively. According to the Kaplan-Meier estimator, aortoiliac lesions had lower reintervention rates than femoropopliteal lesions (Log-rank p = 0.010), and cases without narrowing atheromatous plaque had a lower reintervention rate (Log-rank p = 0.049). Age was an independent risk factor for death (p = 0.038, hazard ratio 1.076, 95% confidence interval 1.004-1.153).

Conclusions: The single-centre protocol of catheter-directed thrombolysis we proposed for acute lower limb ischaemia was effective and safe. Strict blood pressure control during catheter-directed thrombolysis ensured safety. Aortoiliac lesions and cases without narrowing atheromatous plaque had lower reintervention rates during follow-up.