Catheter-directed thrombolysis protocols for deep venous thrombosis of the lower extremities - a systematic review and meta-analysis

Objective: To summarize characteristics, complications and success rates of different catheter-directed thrombolysis (CDT) protocols for the treatment of lower extremities (LE) deep venous thrombosis (DVT). Methods: A systematic review using electronic databases (MEDLINE, Scopus and Web of Science) was performed to identify randomized controlled trials and observational studies related to LE-DVT treated with CDT. A random-effect model meta-analysis was performed to obtain the pooled proportions of early complications, post-thrombotic syndrome (PTS) and venous patency. Results: Forty-six studies met the inclusion criteria reporting 49 protocols (n=3,028 participants). In studies that addressed the thrombus location (n=37), LE-DVT had iliofemoral involvement in 90±23% of the cases. Only 4 series described CDT as the solely intervention for LE-DVT, while 47% received additional thrombectomy (manual, surgical, aspiration or pharmaco-mechanical) and 89% used stenting. Definition of venogram success was highly variable, being the Venous Registry Index the most used method (n=19). Among those, minimal thrombolysis rate (<50% lysed thrombus) was 0-53%, partial thrombolysis (50-90% lysis) was 10-71% and complete thrombolysis (90-100%) was 0-88%. Pooled outcomes were 8.7% (95%CI 6.6-10.7) for minor bleeding, 1.2% (95%CI 0.8-1.7%) for major bleeding, 1.1% (95%CI 0.6-1.6) for pulmonary embolism and 0.6% (95%CI 0.3-0.9) for death. Pooled incidences of PTS and of venous patency at up to 1 year of follow-up were 17.6% (95%CI 11.8-23.4) and 77.5% (95%CI 68.1-86.9), respectively. Conclusions: Assessment of the evidence is hampered by the heterogeneity of protocols, which may be reflected in the variation of PTS rates. Despite this, CDT is a low-risk treatment for LE-DVT.