Sorry...this rambles long...
Amen to what Ross offered. Stenosis doesn't cause ED, unless you're all the way to the point at which you're fainting from it. In which case, ED isn't the biggest alligator in your swamp.
You've likely been put on a beta blocker. This is a very common side effect of blood pressure medications, particularly beta blockers. When they talk about high blood pressure causing ED, they are mostly actually referring to the treatments for high blood pressure causing ED.
And they do a great job of "spinning" it. I've heard and read that people with diabetes, psoriasis, and ED often have high blood pressure (hypertension), as if hypertension was the link between them. It appears that a more accurate statement would be that people who take high blood pressure medications are more apt to have diabetes, psoriasis, and ED (the beta blocker thus being the "magical" link to HBP).
Beta blocking compounds work basically by interfering with various chemical reactions in your blood that cause your body to raise blood pressure, sort of like a pharmaceutical shotgun blast. Some interfere with renin release by JG (juxtaglomerular) cells, or bind to renin released by the kidneys, which would otherwise cause a cascade of blood-pressure-elevating issues.
Badly oversimplified: renin causes angiotensinogen in the blood to split, creating angiotensin I, some of which is converted (mostly in the lungs) to Agiotensin II. AII it the big villain, doing the yeoman's job of upping the blood pressure. It causes blood vessels to constrict, raising blood pressure through resistance. It also stimulates the release of aldosterone and vasopressin, which increase blood volume and cause the kidneys to retain salt and more fluid, also raising the BP. It stimulates thirst, raising blood volume further, and stimulates the heart to pump harder.
Unfortunately, these beta blockers also bind with and inhibit other chemicals in the body, and interfere with other processes that are not harmful (thus the shotgun blast analogy). Not all of these interactions are understood. Some things that seem to be in the mix: control of blood vessels that activate and maintain the functional usefulness of the male organ; various immune functions that keep us from developing skin problems, including intestinal skin difficulties; and the balance of sugar levels in our sytems.
Some people's bodies find ways around the beta blockers, and some don't. Most people will be largely and happily unaffected, a few will suffer psoriasis, some more will develop diabetes, and even more than that will suddenly find out what ED stands for.
So, the bad news is that beta blockers drugs tend to cause ED. But the good news is that there are a lot of different beta blockers, as well as ACE inhibitors and calcium channel blockers, and there is a good likelihood that there is one or a combination that you can use that will control your BP (or the impact of your heartbeat) that won't cause ED for you.
The bottom line is that there is no reason to suffer from side effects of one particular drug or beta blocker. Each compund is different, and each human chemical system is different. Get your cardiologist to try you on another, and don't take no for an answer.
Best wishes,
