Endothelial Dysfunction Markers as Predictors of Clinical Response to Daily Tadalafil in Men With Vasculogenic Erectile Dysfunction
This prospective cohort study will recruit eligible men attending the Urology/Andrology outpatient clinic. Baseline assessment will include demographic and clinical data, cardiovascular risk assessment, erectile-function questionnaires, routine laboratory investigations, brachial artery flow-mediated dilatation, carotid intima-media thickness, and selected circulating endothelial biomarkers including endothelin-1, nitrite/nitrate, high-sensitivity C-reactive protein, soluble vascular cell adhesion molecule-1, and soluble intercellular adhesion molecule-1. All participants will receive tadalafil 5 mg once daily for 12 weeks. Erectile function, adherence, and adverse events will be assessed during follow-up. The primary outcome will be clinical response at 12 weeks, defined as an improvement of at least 4 points in the IIEF-EF domain together with a positive response to the Global Assessment Question.
• Participants must fulfill all of the following:
‣ Men aged 30 to 70 years.
⁃ ED lasting at least 3 months.
⁃ IIEF-5/SHIM score of 21 or less or clinically documented ED.
⁃ Clinical features suggesting predominantly vasculogenic ED.
⁃ Sexually active or willing to attempt sexual intercourse during the study.
⁃ Able to complete the study questionnaires.
⁃ Willing to take tadalafil 5 mg once daily for 12 weeks.
⁃ Able to provide written informed consent.
⁃ Willing to avoid other ED treatments during the study unless medically necessary.