Introduction: For patients undergoing heart transplantation, an elevated pulmonary vascular resistance (PVR) increases mortality in the early post-heart transplant period. This study aimed to assess the effects of chronic sildenafil administration on the PVR, transpulmonary gradient (TPG), and cardiac output (CO) in patients with heart failure awaiting heart transplantation.
Method: The data from serial right heart catheterizations (RHC) of six patients were analyzed. All patients demonstrated a reaction to the vasodilators glyceryl trinitrate or inhaled iloprost at initial RHC before commencing sildenafil. A follow-up RHC was performed as required to guide management.
Results: The average total daily dose of sildenafil was 100 mg for a period of 68+/-58 days (4-145). The average TPG at baseline was 23.7 mmHg and fell in 4 of the 6 patients (67%) with an average reduction of 4.5+/-7.3 mmHg (-5 to 14). The average PVR at baseline was 571 dyn s cm(-5) and fell in 5 of 6 patients (83%), with an average reduction of 167+/-266 dyn s cm(-5) (74-518). The CO at baseline was 3.95 L/min and rose in 5 of 6 patients (83%) with an average improvement of 0.58 L/min (-1.1 to 1.3). The mean pulmonary capillary wedge pressure (MPCWP) at baseline was 26.3 mmHg and fell in 5 of 6 patients (83%) with an average fall of 5.5 mmHg (-1 to 17). Four of the six patients achieved a final TPG<15 mmHg, which we consider to be acceptable for orthotopic heart transplantation, average 11 mmHg (8 to 13). Three of these patients have already undergone successful, uncomplicated heart transplantation.
Conclusion: Chronic sildenafil use is safe and effective in reducing an elevated TPG and PVR in patients with heart failure requiring heart transplantation and allows patients to be transplanted who may otherwise have been excluded because of pulmonary hypertension.