Toni Braxton's Microvascular Angina: FAQ
Singer Diagnosed Just Before Stint on Dancing With the Stars
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What is microvascular angina (cardiac syndrome X)?
"In 95% of cases, lack of blood flow to the heart is due to blockages in one or more of the three main coronary arteries. Somewhere under 5% of the time, instead of major artery blockages, people have atherosclerosis in very small arteries.
"Picture the heart as the trunk of a tree. To get blood to the muscles, the tree roots branch out into smaller and smaller vessels. When these little vessels get diseased, as you exercise, you can't get enough blood to the heart."
How do doctors diagnose microvascular angina (cardiac syndrome X)?
"Cardiac syndrome X is a diagnosis of exclusion. We don't have equipment that does microscopic dissections of these small blood vessels. So this is mainly diagnosed by symptoms.
"To diagnose this, we try to bring on pain in a stress test. We have patients walk rapidly, so the heart beats very fast. If there is angina, we do a coronary angiography to look for blockages in the major arteries. That is probably what happened to Toni Braxton. If she had angina and no blockages in major arteries, that's probably when they diagnosed microvascular angina."
Did Toni Braxton's previous pericarditis cause her microvascular angina? Might her doctors have misdiagnosed her microvascular angina four years ago?
"Pericarditis could not have led to microvascular angina. There are definite changes on medical tests that lead to a diagnosis of pericarditis, so it is hard to conjecture as to how that diagnosis was made. But let us assume she did have pericarditis: That is not going to lead to angina."
How is microvascular angina treated?
"In my armamentarium, I use drugs to dilate the coronary arteries: long-lasting nitrates such as the nitroglycerin patch; then calcium-channel blockers such as verapamil [brand names include Calan, Covera, Isoptin, and Verelan] or diltiazem [brand names include Cardizem, Cartia, Dilacor, Diltia, and Tiazac].
"Then the other new drug which is really promising is Ranexa, which works by a totally different mechanism on the metabolism of the heart. It is an incredible anti-angina drug but does not have FDA approval for that indication. I have shifted a lot toward use of Ranexa for these patients. [O'Neill has no financial link to the makers of this drug].
"Exercise is also a good thing to do. What I tell people is to exercise to the threshold of symptoms, then cut back. So if you get angina after running three miles on the treadmill, cut back to two miles, then gradually build up. The more you exercise, the more you are able to exercise."