The Hidden Heart Disease Even Doctors Miss

It’s hard to imagine that, with all the technology available today, heart disease could be completely missed. But that’s exactly what’s frequently occurring with a tricky heart condition known as small vessel disease or coronary microvascular disease (MVD).

Here’s what happens: Patients, most often women, have chest pain, other symptoms that suggest heart disease or even heart attacks. But when doctors examine their coronary arteries, they find no evidence of blockage and often rule out heart disease. Result: Patients go without the vital treatment they need.

Mystery solved: The problem in these cases, researchers have recently discovered, often lies in the tiny blood vessels—which can’t be seen with the naked eye or conventional heart disease testing—that branch off the larger coronary arteries in the heart.

Researchers still have much to learn about MVD, but here’s what’s known now and what you can do to protect yourself…

 A Different Kind of Heart Disease

The most common variety of coronary heart disease (CHD) is caused by atherosclerotic plaques—­cholesterol-containing deposits that pile up and narrow one or more of the large arteries that carry blood to the heart, restricting flow. When the heart gets too little blood to meet its needs—during exertion, for example—people with CHD have chest pain (angina). And if blood flow is restricted even further—usually due to a clot lodged in the narrowed artery—a heart attack and death may occur.

Plaque is often involved in MVD, too. But instead of accumulating in clumps that block off segments of specific coronary arteries, cholesterol is deposited more evenly inside whole areas of microscopic circulation. Additionally, in MVD the walls of the tiny arteries are injured or diseased—instead of opening wider to allow more blood to reach the heart during exercise or at times of emotional stress, they tighten up, constricting blood flow when it’s needed most.

The reason for this is unclear, but it seems that at least some of the time, it’s due to malfunction of the endothelial cells that line the blood vessels. The resulting symptoms can be indistinguishable from ­garden-variety CHD—and the risk for heart attack may be just as real.

Do You Have Microvascular Disease?

Diabetes and high blood pressure raise one’s risk for MVD, as does CHD. High cholesterol, obesity, smoking and a lack of physical activity are risk factors, too, and like CHD, MVD becomes more common with advancing age.

Symptoms of MVD can be identical to the classic signs of CHD—pain, a squeezing sensation or pressure in the chest, usually during activity or emotional stress. The discomfort can also occur in the shoulders, arms, neck or jaw.

MVD tip-off: Painful episodes of MVD usually last longer—more than 10 minutes, and sometimes longer than 30 minutes—than those of classic CHD.

Other symptoms of MVD: Fatigue or lack of energy, trouble sleeping and shortness of breath. Women are particularly likely to have these vague manifestations rather than the kind of distinct chest pain that we usually associate with heart disease. Forty percent of women don’t have chest pain even while having a heart attack, whether it’s caused by CHD or MVD.

Another clue: With MVD, patients often notice symptoms during daily activities and/or during times of mental stress rather than during times of physical exertion as is more often the case with CHD. 

Getting a Diagnosis

The standard tests for heart disease may not uncover MVD. If you suspect you have the condition, be sure to see a cardiologist with significant experience in treating MVD. An academic medical center is the best place to find such a doctor. He/she may be able to diagnose it from your symptoms, medical history and earlier test results, or he may order additional tests…

Nuclear imaging, which uses a radioactive compound injected into the bloodstream to reveal a detailed image of the heart and blood flow through the arteries, including microcirculation.

Magnetic resonance imaging (MRI) to produce a picture of the heart and its circulation without subjecting the patient to dye or ­radiation.

Positron emission tomography (PET), which provides information on metabolism in the heart. This can uncover certain areas that aren’t getting enough fuel and oxygen, suggesting MVD.

If You Have MVD

If MVD is diagnosed, the goal is to keep it from progressing and to prevent heart attack and stroke. Key strategies…

Tweak your diet, and punch up your exercise routine. A healthy eating plan, such as the Mediterranean diet, emphasizes fruits, vegetables, legumes, whole grains and nuts and fish, which contain healthy fats. Weight control and exercise reduce heart disease risk overall and also reduce blood pressure and help prevent diabetes, which are additional MVD risk factors. Beyond its general cardiovascular benefits, regular exercise appears to improve the function of the endothelial cells that line blood vessels and function poorly in MVD.

Get help from medication. Doctors prescribe the same medications to treat MVD as for CHD—to reduce blood pressure and cholesterol. Aspirin or other drugs to ­reduce clotting risk are recommended as well.

Some evidence suggests that statins may be particularly useful because they not only reduce cholesterol but also improve endothelial function and relax the muscles around tiny blood vessels.

Similarly, calcium channel blockers, such as amlodipine (Norvasc), and ACE inhibitors, like enalapril (Vasotec), may be good choices for lowering blood pressure because they too help keep arteries open.

Get treated for anemia if you have it. Anemia (low red blood cell count) may slow the growth of cells that help repair artery walls. This  condition is treated with iron or B-12 supplements.

Note: If you have CHD and MVD (it’s possible to have both) and have had angioplasty, a stent or bypass surgery, be aware that these procedures do not help MVD.