Coronary Artery Flow Reserve in Diabetics with Erectile Dysfunction Using Sildenafil

Background: Diabetics with erectile dysfunction have a high prevalence of microvascular disturbance of the coronary circuit as measured by coronary flow reserve (CFR).

Purpose: We aimed to evaluate the effects of the phosphodiesterase 5 inhibitor sildenafil on CFR in diabetics with erectile dysfunction.

Methods: Diabetics seeking diabetes refinement therapy were screened for vascular or neurogenic erectile dysfunction which was confirmed in 43 patients. No ischemic ECG changes were found in any of the ECG stress tests at the 100 W level. Cardiologic examinations raised suspicion of coronary artery disease in 16 patients; coronary angiography confirmed severe coronary artery lesions in 12, who were excluded from further analysis. CFR measurements were not possible in 10 participants. The 21 diabetics eligible for CFR measurements aged 60 years (50-69) had known diabetes for 11 years (3-30) and a BMI of 27 kg/m2 (24-36). CFR of the left anterior descending artery was assessed at baseline and 1 hour after 50 mg sildenafil, using transthoracic Doppler echocardiography.

Results: Baseline CFR was at the lower level of the normal range (median 245%, range 210-490%). After sildenafil administration, CFR decreased insignificantly (DeltaCFR -10%, p = 0.3). Patients with a BMI > 25 kg/m2 and left ventricular hypertrophy exhibited the highest reduction of CFR after sildenafil. No decrease of CFR below 200 % was observed. Systemic blood pressure dropped from 130/80 mmHg to 120/72 mmHg (p < 0.002).

Conclusions: Diabetics with erectile dysfunction exhibit a CFR in the lower normal range indicating severe microvascular disturbance. Sildenafil did not alter CFR in those patients. A high prevalence of severe coronary macroangiopathy was identified in asymptomatic diabetic patients screened for contraindications for sildenafil.