Prosthetic Valve Thrombosis: Thrombolytic Agent Selection and Imaging Guidance

We read with great interest the article by Sadiq et al reporting a 10-year single-center experience with thrombolysis for leftsided mechanical valve thrombosis, including a comparative analysis between streptokinase and tenecteplase and the identification of independent predictors of treatment failure. 1 The authors should be commended for providing one of the largest contemporary real-world cohorts in this challenging clinical scenario and for addressing a clinically relevant question that remains incompletely resolved in routine clinical practice.Their findings further highlight an increasingly important contemporary issue in prosthetic valve thrombosis management: although fibrin-specific agents and protocolized imagingguided strategies may offer superior outcomes, streptokinase continues to represent a clinically relevant therapeutic option in carefully selected patients, particularly in resource-limited settings.Several findings merit further discussion.First, the overall success rate of 76.3%, with an in-hospital mortality of 6.8% and a low incidence of major hemorrhage, is consistent with international registries and reinforces the continued relevance of fibrinolytic therapy in appropriately selected patients.Importantly, tenecteplase was associated with higher success (82.4% vs 70.9%) and lower mortality than streptokinase, despite a higher frequency of dosing deviations.These observations further support the growing preference for fibrin-specific agents when thrombolysis is chosen and suggest more predictable pharmacodynamics with the potential for faster clot resolution.However, despite the growing preference for fibrin-specific agents in contemporary practice, streptokinase remains a useful therapeutic alternative in many low-and middle-income regions because of availability and cost considerations.Earlier prospective and observational experiences demonstrated that streptokinase can achieve acceptable efficacy and safety when applied in carefully selected patients.In our cohort of 68 patients with prosthetic valve thrombosis, thrombolysispredominantly with streptokinase-was used as first-line therapy and achieved satisfactory hemodynamic and clinical outcomes, supporting its role as a viable strategy in resource-constrained settings.2 Although observational, our earlier cohort predates contemporary low-dose slow-infusion protocols and modern multimodality imaging strategies, limiting direct comparability with current practice.The higher failure rate observed with streptokinase in the present study may therefore reflect not only intrinsic pharmacologic differences but also heterogeneity in patient risk profile, thrombus burden, dosing strategies, and diagnostic confirmation prior to treatment-factors that are difficult to fully control in retrospective analyses.The emergence of newer randomized data further contextualizes these findings.The TENET randomized clinical trial demonstrated the efficacy and safety of tenecteplase compared with alteplase in mechanical prosthetic valve thrombosis, further supporting the evolving role of fibrin-specific agents in contemporary thrombolytic strategies.3 However, the trial did not directly evaluate comparisons with streptokinase.Together with the results of Sadiq et al, these findings suggest that agent selection may increasingly influence outcomes as treatment strategies evolve toward greater precision and protocolization.Another clinically important observation is the strong association between failure of thrombolysis and the absence of fluoroscopic assessment before therapy (adjusted OR 3.77).1 Misclassification of pannus, structural degeneration, or mechanical dysfunction as thrombotic obstruction may expose patients to ineffective fibrinolysis and unnecessary risk.This finding underscores the need for a multimodality imaging approach before initiating thrombolytic therapy, integrating