Low dose slow and ultraslow thrombolytic therapy for patients with prosthetic valve thrombosis: a pharmacist-led protocol experience from a Middle Eastern quaternary care center

Background Slow and ultraslow infusions of low-dose thrombolytic therapy (TT) have emerged as promising alternatives for managing mechanical prosthetic valve thrombosis (PVT), potentially enhancing thrombus resolution while reducing bleeding complications. This study presents real-world clinical outcomes using low-dose alteplase regimens administered according to a pharmacist-led institutional protocol. Methods A retrospective cross-sectional study was conducted at a multispecialty quaternary care hospital in the United Arab Emirates. Twelve patients presenting with heart failure symptoms and confirmed PVT received low-dose alteplase thrombolytic regimens. The protocol involved either a slow infusion (25 mg over 6 hours) or an ultraslow infusion (25 mg over 25 hours). Clinical characteristics, treatment regimens, and outcomes were assessed. Results Most patients presented with New York Heart Association (NYHA) class II and III symptoms, representing 50% and 41.7% of cases, respectively. Mitral valve thrombosis was observed in 58.3% of patients, aortic valve thrombosis in 33.3%, and one patient exhibited thrombi involving both valves. The ultraslow infusion protocol was applied in 91.7% of cases. The median total alteplase dose administered was 47.9 mg (range 25 to 125 mg), delivered over one to five doses. Clinical success, defined as complete or partial resolution of valve thrombosis, was achieved in 50% of patients after the first dose and 83.3% after the second dose. One patient experienced an ischemic stroke. Bleeding complications occurred in one third of patients, with only one major bleeding event. All patients survived at one-month follow-up, and one patient required valve surgery. Conclusion Low-dose slow and ultraslow alteplase thrombolytic regimens demonstrated favorable clinical outcomes in patients with symptomatic PVT within a real-world clinical setting. Despite limitations inherent to a retrospective observational design and small sample size, these findings support pharmacologic thrombolysis as a potential alternative to surgery in selected patients. Larger prospective studies are required to further define optimal thrombolytic regimens and patient selection criteria.