The adhesiveness of human blood platelets and thyroid function.

Area of Science:

• Cardiology
• Endocrinology
• Hematology

Background:

• Hypothyroidism is associated with severe coronary atherosclerosis.
• Despite this, the incidence of angina pectoris and myocardial infarction is paradoxically low in untreated hypothyroidism.
• Thrombus formation is a key event in myocardial infarction, suggesting platelet function may be altered.

Purpose of the Study:

• To investigate the role of platelet adhesiveness in the paradoxical rarity of myocardial infarction in hypothyroidism.
• To evaluate changes in platelet adhesiveness before and after treatment in hypothyroid and thyrotoxic patients.

Main Methods:

• Platelet adhesiveness was measured in 9 hypothyroid and 16 thyrotoxic patients.
• Measurements were taken before and after thyroid hormone replacement therapy.

Main Results:

• Thyrotoxicosis showed significantly increased platelet adhesiveness, which normalized post-treatment.
• Hypothyroidism exhibited abnormally low platelet adhesiveness, increasing to normal levels after thyroid hormone replacement.

Conclusions:

• Altered platelet adhesiveness may explain the low incidence of myocardial infarction in hypothyroidism.
• Thyroid hormone replacement normalizes platelet adhesiveness in both hypothyroidism and thyrotoxicosis.
• Platelet function changes might be a crucial factor in myocardial infarction risk for patients with hypothyroidism and coronary artery disease.