Concerns about the safety of sildenafil in patients with cardiovascular disease have been raised as a result of reports of myocardial infarction and sudden death shortly after ingestion of this agent. Whether such cardiac events are related to the drug, to underlying heart disease or to a combination of factors is unclear. To investigate whether sildenafil has adverse cardiovascular effects, Herrmann and colleagues measured the systemic and coronary hemodynamic effects of this agent in 14 men (mean age: 61 years) with stable severe coronary artery disease.

All of the men had more than 70 percent stenosis of at least one coronary artery and had been referred for percutaneous transluminal coronary angioplasty. They were asymptomatic and had not taken nitrates for at least 24 hours before the hemodynamic studies. Other medications such as beta blockers, aspirin and angiotensin-converting enzyme inhibitors were continued as needed.

The hemodynamic effects of sildenafil were evaluated by measuring the arterial pressure in the coronary orifice, pulmonary capillary wedge pressure, pulmonary artery pressure, right atrial pressure, heart rate, cardiac output, average peak flow velocity, coronary artery diameter, volumetric coronary blood flow and coronary vascular resistance before and 45 minutes after administration of 100 mg of sildenafil.

Administration of sildenafil was followed by small (less than 10 percent) but significant decreases in arterial blood pressure and pulmonary pressure. No significant changes were noted in heart rate, cardiac output, cardiac index, right atrial pressure and pulmonary capillary wedge pressure.

The effects of sildenafil on coronary artery diameter and blood flow were measured in 25 arteries, including 13 severely diseased arteries and 12 reference arteries in the same patients. No significant changes were documented in the coronary artery diameter, coronary blood flow and coronary vascular resistance, in either diseased or normal arteries. Overall, no adverse events were recorded, including symptomatic hypotension or chest pain.

The authors conclude that oral sildenafil has no direct adverse cardiovascular effects in men with severe coronary artery disease. The findings of this study suggest that sildenafil is safe for use in patients with stable severe coronary artery disease, provided the men are not receiving nitrate-containing medications.