Factors Associated with Ineffectiveness of Sildenafil Treatment in Patients with End-Stage Heart Failure and Elevated Pulmonary Vascular Resistance.

Higher concentrations of TNC, fibrinogen and creatinine, as well as a larger RVEDd are independently associated with the ineffectiveness of sildenafil treatment. TNC has the strongest predictive power, sensitivity and specificity for evaluation of resistance to sildenafil treatment.