Prolonged Infusions of Low-Dose Thrombolytics in Elderly Patients with Prosthetic Heart Valve Thrombosis

Background: The outcomes of thrombolytic therapy (TT) in elderly patients with prosthetic valve thrombosis (PVT) have not been evaluated previously. We investigated the outcomes of low-dose and slow infusion TT strategies in elderly patients with PVT. Methods: Twenty-seven (19 female) patients aged ≥65 years (median: 70 years, range: 65-82 years) were treated with repeated TT agents for PVT. The TT regimens included 24-hour infusion of 1.5 million units of streptokinase in 2 patients, 6-hour infusion of 25 mg recombinant tissue plasminogen activator (t-PA) in 12 patients, and 25-hour infusion of 25 mg t-PA in 13 patients. Treatment success and adverse event rates were assessed. Results: The initial and cumulative success rates were 40.7% and 85.2%, respectively. Adverse events occurred in 6 (22.2%) patients including 4 (14.8%) major (1 death, 1 rethrombosis, and 2 failed TT) and 2 (7.4%) minor (1 transient ischemic attack and 1 access site hematoma) events. Higher thrombus burden (thrombus area ≥1.1 cm² by receiver operating characteristics analysis, sensitivity: 83.3%, specificity: 85%, area under the curve: 0.86, P =.008) and New York Heart Association class (0% vs 15.4% vs 25% vs 100% for classes I-IV, respectively, P =.02) predicted adverse events. By multiple variable analysis, thrombus area was the only independent predictor of adverse events (odds ratio: 13.8, 95% confidence interval: 1.02-185, P =.04). Conclusion: Slow infusion of low doses of TT agents (mostly t-PA) with repetition is successful and safe in elderly patients with PVT. However, excessive thrombus burden may predict adverse events.