SIOVAC: Sildenafil in Treating Residual Pulmonary Hypertension in Valvular Heart Disease Patients

Sildenafil should not be used to treat residual pulmonary hypertension in patients with valvular heart disease based on results from the SIOVAC trial presented on Aug. 28 during ESC Congress 2017 in Barcelona.

Sildenafil, typically used to treat erectile dysfunction, is frequently prescribed as an off-label indication in patients with retrograde pulmonary hypertension. The SIOVAC trial is the first to test sildenafil’s use in improving long-term outcomes in patients with successfully corrected valvular disease and residual pulmonary hypertension.

Researchers randomized 200 patients from public hospitals in Spain to either sildenafil (40 mg tid) or placebo over six months. The primary endpoint was the clinical composite score of all-cause death, hospital admission for heart failure, worsening exercise tolerance and feeling worse than when starting the medication (assessed by change in a self-assessment score).

Overall results showed major clinical outcomes were worse and occurred earlier and more frequently in the sildenafil group compared with placebo. At six months, more than twice the percentage of patients taking sildenafil (33 percent vs. 15 percent) had a worse composite clinical score than at the beginning of the trial. Similarly, patients taking sildenafil were at double the overall risk for hospital admission, compared with those taking placebo. Three patients taking sildenafil and two patients taking placebo died during the study (p = 0.63).

Principal investigator Javier Bermejo, MD, Hospital General Universitario Gregorio Marañon, Madrid, Spain, said he and fellow investigators were surprised by the findings. “We were unable to identify any particular subset of patients who could potentially benefit from sildenafil,” he said. “Long-term usage of sildenafil for treating residual pulmonary hypertension in patients with valvular heart disease should be avoided. The high incidence of events during the trial emphasizes the need for further research to prevent and treat this complication in patients with valvular disease.” 


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