Placebo controlled,randomised,crossover study of the efficacy of bosentan in the management of patients with Coronary Slow Flow Phenemenon

This study is testing whether a medication called bosentan can help people with a condition called Coronary Slow Flow Phenomenon — where blood flows abnormally slowly through the heart's arteries, causing chest pain. Bosentan works by relaxing blood vessels. This is a crossover study, meaning participants will try both the real medication and a placebo at different times. You may be eligible if: - You have been diagnosed with Coronary Slow Flow Phenomenon - You are 18 years of age or older - You have chest pain (angina) occurring more than 3 times per week You may NOT be eligible if: - You have pulmonary hypertension (high blood pressure in the lungs) - You have liver disease - You are currently taking cyclosporin, glibenclamide, or ketoconazole (these medications interact with bosentan) Talk to your doctor about whether this trial might be right for you.