An elevation of homocysteine is due to impaired renal clearance and changes in thyroid hormones on the metabolism of folic acid. In contrast, subclinical hypothyroidism is associated with hyperhomocysteinemia. C-reactive protein (CRP) is an acute phase protein that circulates in higher concentrations in a variety of acute and chronic diseases. CRP significantly increased in clinical and subclinical thyroid problems.
It seems that there is an increased risk of thrombosis, which can precipitate myocardial infarction in mild hypothyroidism, and bleeding tendency during intense hypothyroidism. It has been observed in different studies, decreased fibrinolytic activity with D-dimer levels, increased activity of antiplasmin-2 and higher levels of tissue plasminogen activator. Although hypothyroidism does not appear to cause insulin resistance, low levels of thyroid hormones can amplify a larger increase in risk of cardiovascular disease associated with insulin resistance, a normal TSH levels are high, and higher LDL cholesterol.
Hypermetabolic state of hypothyroidism reduces the peripheral O 2 use, cardiac work with bradycardia and a reduction of myocardial contractility. Thyroid hormones accelerate tissue calorigenesis, exert a positive chronotropic and inotropic effects on the heart leads to the possibility that replacement therapy may increase myocardial infarction, since the impairment of coronary vasodilation in hypothyroid patients. There are anecdotal reports of radiation ablation in the treatment of intractable angina with improved anginal symptoms 76 %.
Cardiac surgery should not be delayed for thyroid hormone replacement. Percutaneous coronary angioplasty is an attractive alternative to coronary artery bypass surgery in patients at high risk for surgery because of associated medical conditions such as hipotireoza. After angioplasty in patients with hypothyroidism is no difference between hypo-and euthyroid patients. Compared with the results of coronary artery bypass surgery in hypothyroid patients is better with angioplasty.
subclinical hypothyroidism does not seem to be a risk factor as a procedural failure of coronary angioplasty is an option with low morbidity in patients with hypothyroidism who require coronary revascularization. It can be concluded that hypothyroidism predisposes patients to increased risk for cardiovascular disease, and levothyroxine therapy can help reduce this risk, patients have a better quality of life and lower morbidity and mortality.
Although it is a clear need to treat patients with overt hypothyroidism, levothyroxine treatment for people with subclinical hypothyroidism and even cause much controversy, because although on the one hand there are the damages attributable to the increase of TSH, the lack of symptoms such as long-term therapy and side effects make it difficult for physicians and patients to reach an agreement on the need for its use.
