[Sildenafil does not change coronary flow reserve in diabetics with erectile dysfunction]

Disturbance of the microvascular coronary circuit is common in diabetics with erectile dysfunction. We investigated effects of sildenafil on coronary flow reserve (CFR) of the left anterior descending branch.

43 diabetics (aged 59 +/- 7 years) with erectile dysfunction and without symptoms of coronary artery disease were selected. Cardiac diagnosis, including stress ECG and echocardiography was performed in all. Because of the clinical suspicion of coronary artery disease coronary angiography was performed in 16 of them. Severe coronary artery disease was confirmed in 12 patients who were excluded from further analyses as well as 10 diabetics in whom coronary flow measurements were not possible. In the other 21 diabetics, adenosine-mediated CFR was calculated at baseline and 1 hour after ingestion of 50 mg sildenafil by transthoracic Doppler echocardiography.

CFR at baseline was at the lower level of the normal range in 17/21 diabetics (median 245 %, range 210 - 490 %). CFR decreased insignificantly in 12/21 patients after sildenafil administration (Delta CFR -10 %, p = 0.3). Patients with a body mass index > 25 kg/m(2), and left ventricular hypertrophy had the highest reduction of CFR after sildenafil, but a drop of the CFR below 200 % was not observed in any patient. Systemic blood pressure dropped significantly from 130/80 mmHg to 120/72 mmHg (p < 0.002).

Diabetics with erectile dysfunction often have a CFR in the lower range of normal. Sildenafil did not further reduce CFR. Asymptomatic, severe coronary artery disease often can be found in diabetics with erectile dysfunction. Cardiological screening for contraindications for sildenafil seems mandatory in diabetics with a high cardiovascular risk profile.