Sildenafil To Prevent Clot

Study Summary

The advent of continuous flow (CF) pumps for patients with severe heart failure has led to marked improvements in survival; however, pump operation remains fraught with adverse thrombotic events. This climbing rate of thrombosis and stroke during CF pump support has led to a recent warning by the US Food and Drug Administration. Despite a rising incidence of pump thrombosis and its downstream complications of stroke, the hematologic mechanisms behind these devastating adverse events remain uncertain. Recently, it has been recognized that CF pump induced hemolysis precedes and is associated with thrombosis. In-vitro studies show increased platelet function with exposure to products of hemolysis, which is also known to occur in diseases of intravascular hemolysis such as sickle cell anemia. This proposal will investigate if hemolysis associated increased platelet function can be reduced by a potentiation of nitric oxide signaling by an oral phosphodiesterase-5 inhibitor, sildenafil. Elucidating mechanisms of hemolysis induced thrombosis may inform best strategies for prevention of end organ damage and maintaining optimal CF pump operation.

Primary Outcome

During the study period platelet activation and aggregation will be measured from drawn blood samples. Platelet rich plasma will be isolated from these samples and platelet aggregometry will be used to measure platelet activation and aggregation. Platelet activation and aggregation is measured as an area under the curve (AUC) derived as the resistance (ohms) x time (s). There is no reference range for ADP induced AUC. Higher values of AUC indicate greater platelet aggregation.

Conditions Studied

Interventions

• DRUG Placebo Oral Tablet
• DRUG Sildenafil

Study Locations (1)