The dynamic changes of brain natriuretic peptide level in patients with hyperthyroid heart disease after 131I therapy

Abstract

Objective To investigate the application value of urine brain natriuretic peptide (BNP) level in 131Ⅰ treatment of hyperthyroid heart disease.Methods One hundred and eleven hyperthyroidism patients who received 131Ⅰ therapy were divided into two groups,hyperthyroidism group(51 cases) and hyperthyroid heart disease group (60 cases),and 30 healthy subjects as control.Sixty patients in the hyperthyroid heart disease group all received ultrasonic cardiogram.The hyperthyroid heart disease group was divided into two subgroups according to New York Heart Association (NYHA) functional classification (hyperthyroid heart disease A subgroup and hyperthyroid heart disease B subgroup).The urine and serum BNP level and serum free triiodothyronine (FT3),free thyroxine (FT4) level were measured through chemiluminescence before and after therapy.Results The urine and serum BNP level before 131Ⅰ therapy of the hyperthyroid heart disease group were significantly higher than those of hyperthyroidism group (serum:t=8.98 and 9.52,both P＜0.01;urine:t=10.83 and 12.73,both P＜0.01)and the control group (serum:t=8.97 and 9.52,both P＜0.01; urine:t=9.21 and 5.64,both P＜0.01).The urine and serum BNP level before and 6,12 months after 131Ⅰ therapy of the hyperthyroid heart disease A subgroup were significantly higher than those of hyperthyroid heart disease B subgroup (serum:t=5.98,5.87 and 6.35,all P＜0.01; serum:t=4.33,4.09 and 5.02,all P＜0.01).The urine level of BNP was gradually increased with the severity of cardiac insufficiency and it was positively correlated with the serum level of BNP(r=0.829,P＜0.01),the NYHA functional classification (r=0.751,P＜0.01)and the serum level of FT3 and FT4 (FT3:r=0.635,P＜0.01; FT4:r=0.672,P＜0.01).Conclusions The urine BNP level of hyperthyroid heart disease patient increased with the severity of cardiac insufficiency.The urine BNP level could accurately reflect cardiac function of hyperthyroid heart disease patient,and could be used as objective indicator for clinical diagnosis,effective evaluation and prognosis evaluation.The urine BNP level has the same value as the serum BNP level. Key words: Hyperthyroid heart disease; Iodine Radioisotope; Natriuretic peptide; Brain; Urinalysis