Avaliação da função do endotélio microvascular sistêmico e peniano e da pressão arterial sistêmica após o uso do citrato de sildenafila em hipertensos com disfunção erétil

Abstract

Erectile dysfunction (ED) of vascular etiology is a highly prevalence health problem and is directly related to an increased cardiovascular risk. Phosphodiesterase type 5 inhibitors in addition to treating ED, as they have the property of increasing the bioavailability of nitric oxide, they could be promising for the treatment of systemic hypertension and to improve vascular endothelial function. The primary aim of this study was to evaluate the acute and chronic effect of sildenafil citrate (SIL) on systemic and penile microvascular endothelium function and systemic arterial pressure in primary arterial hypertension patients with ED. This is a prospective, randomized, double-blind, placebo-controlled, cross-over study. A total of 57 hypertensive men, with erectile dysfunction, aged 57.7±5.8 years and 50 age-matched normotensive subjects were included. The Simplified International Index of Erectile Function (IIEF-5) was used to evaluate erectile function. The evaluation of forearm and penile microvascular endothelial function was performed using laser speckle contrast imaging (LSCI), coupled with acetylcholine (ACh) iontophoresis. All volunteers were evaluated by LSCI before and 1 h after oral administration of SIL 100 mg. Later, only the hypertensive patients were randomized to investigate the chronic effect of SIL. They were treated for four weeks with SIL 50 mg twice daily or placebo, in two steps, with a 30-day washout period between treatments. The blood pressure values recorded at each treatment step was performed through 24 h ambulatory blood pressure monitoring (ABPM). Hypertensive patients had significantly higher mean values of anthropometric and laboratory variables than normotensive individuals. After SIL 100 mg mean arterial pressure fell -4.6±8.3 mmHg in normotensive and -8.2±14.6 mmHg in hypertensive patients. There was a significant increase in basal cutaneous vascular conductance (CVC) values, CVC peak values and in the area under the curve (ASC) of penile microvascular vasodilation of both normotensive and hypertensive patients (P=0.002, P=0.0001 and P=0.001) and (P<0.0001, P=0.004 and P=0.001), respectively. The basal capillary density was higher in hypertensive patients than in normotensives; the same occurred after the post-occlusive reactive hyperemia. After 4 weeks treatment with SIL, there was a significant reduction in diastolic blood pressure (P=0.003) in 24 h ABPM, which did not occur after placebo. Erectile function, measured by IIEF-5, had significant improvement (P<0.0001) only after SIL treatment. Penile microvascular function improved significantly after SIL (basal CVC; P=0.004, CVC peak; P=0.001, ASC; P=0.003), but not after placebo. There was no difference to ACh iontophoresis in the forearm regarding the acute and chronic effect of SIL. Conclusion: In patients with hypertension and erectile dysfunction, acute and chronic administration of sildenafil in addition to optimizing the quality of erectile function, improves penile microvascular function and reduces systemic blood pressure.