Heart Valve Defect Common in Patients With Thyroid Disease

Nov. 30, 1999 (New York) -- A heart valve abnormality is commonly found among people with a specific type of thyroid disease, Greek researchers report in the journal Thyroid.

M.E. Evangelopoulou and colleagues from Alexandra Hospital at Athens University School of Medicine, say doctors should look for the heart valve problem, known as mitral valve prolapse or MVP, in patients with autoimmune thyroid disease. Autoimmune thyroid diseases, such as Graves' disease and Hashimoto's thyroiditis, are conditions in which the body acts against substances such as proteins produced by the thyroid gland.

MVP is a disorder in which the mitral valve does not close properly and allows blood to leak into the left atrium of the heart. MVP is found in about 5% to 15% of people under age 40 but is most common among very thin women.

Graves' disease is characterized by an enlarged thyroid gland and protrusion or bulging of the eyes. Over time, the disease can destroy the thyroid gland. Hashimoto's thyroiditis also is characterized by an enlarged thyroid and an autoimmune reaction to proteins produced in the thyroid. Both diseases occur much more frequently in women than in men.

The researchers studied 29 patients with Graves' disease, 35 patients with Hashimoto's thyroiditis, 20 patients with nonautoimmune goiter (enlarged thyroid gland), and 30 people with healthy thyroids. Cardiac ultrasound was performed in all patients to diagnose MVP and blood samples were examined for presence of substances that signal autoimmune abnormalities.

MVP was found in 28% of patients with Graves' disease, in 23% of patients with Hashimoto's thyroiditis, and in 10% with nonautoimmune goiter. MVP was not present in any members of the healthy group.

Autoimmune abnormalities in blood were found in 63% of the patients with MVP and Graves' disease and in only 14% of the patients with Graves' disease who did not have MVP. In patients with Hashimoto's disease and MVP, a high incidence of autoimmune abnormalities in blood were found 63% of the time. In patients with Hashimoto's thyroiditis who did not have MVP, autoimmune abnormalities in blood were found in only 19%.

In previous studies, MVP has been found in otherwise healthy people with autoimmune disorders such as arthralgias (joint pain), alopecia (loss of hair), and Raynaud's syndrome (a condition in which the fingers get cold and turn blue because of decreased blood flow). David S. H. Bell, MD, published a study in 1996 showing an increased incidence of MVP in patients with type 1 diabetes which also has an autoimmune component.

"I found that 45.1% of patients with type I diabetes had documented mitral valve prolapse," Bell, director of the endocrine clinic at the University of Alabama School of Medicine in Birmingham, tells WebMD. His literature search showed that 41% of patients with Graves' disease and 41% with Hashimoto's thyroiditis also had MVP.

However, when Bell evaluated patients with MVP who did not have Graves' disease or Hashimoto's thyroiditis, he found no increase in genetic markers. "If there is an association with autoimmune disease, it's not showing up in the classic genetic markers we have for autoimmune disease," he says.

Bell tells WebMD he evaluates patients with diabetes for presence of MVP and often uses the MVP diagnosis as criteria for distinguishing between type 1 and type 2 diabetes. He adds that although MVP can be a benign condition, antibiotics are recommended for patients with MVP when undergoing dental work or surgery, therefore, physicians should look carefully for MVP in patients with autoimmune disorders such as diabetes, Graves' disease, and Hashimoto's thyroiditis.

Vital Information:

  • Mitral valve prolapse (MVP) is a heart condition in which the mitral valve does not close properly and blood leaks into the left atrium of the heart.
  • MVP occurs in 5 to 15% of the general population under 40 but is much more prevalent among patients who have autoimmune thyroid disease.
  • Although MVP can be a benign condition, doctors should screen patients with autoimmune thyroid disorders because those who have it will need antibiotics during dental work or surgery.