A Prospective Study on Cardiovascular Dysfunction in Patients with Hyperthyroidism and Its Reversal After Surgical Cure.

Background: Cardiovascular dysfunction (CVD) is a major cause of mortality and morbidity in hyperthyroidism. CVD and its reversibility after total thyroidectomy (TT) are not adequately addressed. This prospective case-control study evaluates the effect of hyperthyroidism on myocardium and its reversibility after TT.

Materials And Methods: Surgical candidates of new onset hyperthyroidism, Group A (n = 41, age < 60 years) was evaluated with 2D Echocardiography, serum n-terminal probrain natriuretic peptide (NT-proBNP) at the time of diagnosis (Point A), after achieving euthyroidism (Point B) with antithyroid drugs, and 3 months after TT (Point C). 20 patients with nontoxic benign thyroid nodules undergoing TT served as controls (Group B).

Results: Both groups were age and sex matched. Group A (n = 41) comprises Graves disease (n = 22) and Toxic Multinodular goiter (n = 19). At point A, CVD was evident in 26/41(63.4%), pulmonary hypertension (PHT) in 24/41(58.5%)--mild in 17/41(41.4%) and moderate in 7/41(17%)--dilated cardiomyopathy (DCM) in 8/41(19.5%), heart failure in 4/41(9.7%), and NT-proBNP elevated in 28/41(68.3%). At point B, recovery was observed in PHT 19/26(73.1%), DCM 4/8(50%), heart failure 4/4(100%), NT-proBNP in 3/28(10.7%). At Point C, further improvement occurred in PHT 23/24(95.8%), DCM 7/8(87.5%), heart failure 4/4(100%), and NT-proBNP in 24/28(85.7%).

Conclusion: Pulmonary hypertension is completely reversible at 3 months after TT and is the most common cardiac event in Hyperthyroidism. Various parameters of CVD improved consistently after surgical cure. NT-proBNP levels correlated well with the severity and duration of CVD and hence can be an objective tool in monitoring of hyperthyroid cardiac dysfunction.