The Impact of Subclinical Hypothyroidism or Thyroid Autoimmunity on Coronary Vasospasm in Patients without Associated Cardiovascular Risk Factors

BACKGROUND AND OBJECTIVES: Subclinical hypothyroidism is associated with endothelial dysfunction and impaired coronary flow reserve. However, the effect of subclinical hypothyroidism or thyroid autoimmunity on variant angina has yet to be determined. SUBJECTS AND METHODS: Among 385 consecutive patients without associated cardiovascular risk factors who underwent coronary angiography with the ergonovine provocation test (EPT), 165 had a positive EPT {EPT(+)} and 220 had a negative EPT {EPT(-)}. The relationship between coronary artery spasm and the presence of subclinical thyroid dysfunction as well as serum thyroid peroxidase autoantibody (TPO Ab) was evaluated. RESULTS: The proportion of patients with subclinical hypothyroidism among those who were EPT(+) was significantly higher than that in those who were EPT(-) (18% vs. 11%, p=0.001). However, there was no significant difference in the proportion of patients with subclinical hyperthyroidism between the groups. Moreover, EPT(+) patients showed significantly more positive TPO Ab (33% vs. 14%, p<0.001) than those with EPT(-). There was a positive correlation between EPT(+) and TPO positivity (r=0.226, p<0.001), subclinical hypothyroidism (r=0.112, p=0.033), and body mass index (r=0.123, p=0.018). Binary logistic regression analysis revealed that the significant predictors of EPT(+) were body mass index {adjusted odds ratio (OR)=1.042, 95% confidence interval (CI)=1.005-1.080}, presence of subclinical hypothyroidism (OR=3.047, 95% CI=1.083-8.572), TPO Ab titer (OR=1.028, 95% CI=1.015-1.041), and the presence of TPO Ab (OR=4.904, 95% CI=1.544-15.567). CONCLUSION: Subclinical hypothyroidism and the presence of TPO Ab are significantly associated with coronary vasospasm in patients without cardiovascular risk factors.

Safety and Validity of Ergonovine Echocardiography before Coronary Angiography for Diagnosis of Coronary Vasospasm

BACKGROUND: Detection of left ventricular regional wall motion abnormality(RWMA) by 2 dimensional echocardiography during ergonovine provocation(Erg Echo) can be used for noninvasive diagnosis of coronary vasospasm(CVS). The aim of this study was to test the safety and diagnostic validity of Erg Echo as a screening test in patients with chest pain syndromes before coronary angiography was undertaken. METHODS: From Mar 1993 to Jun 1994, Erg Echo was performed in 80 consecutive patients (56 males) with chest pain syndromes suggestive of variant angina, after the confirmation of negative treadmill or normal stress myocardial perfusion scan using thallium 201. A bolus of ergonovine maleate was injectedd at 5min intervals up to total cumulative dosage of 0.35mg with echocardiographic montioring of the left ventricular wall motion. Twelve leads ECG was also recorded every 3min after each ergonovine injection. The positive criteria of the test was transient ST segment clevation or depression greater than 0.1mV in 12-leads ECG or development of RWMA. Coronary angiography was undertaken 2(+/-4) days after Erg Echo, and spasm provocation test with acetylcholine, or ergonovine was done in case of normal angiogram or luminal narrowing of less than 70%. The appearance of total or subtotal occlusion of a major coroary artery associated with ST segment elevation or depression on the ECG or chest pain, or both, was considered to be a manifestation of spasm. RESULTS: According to the invasive angiographic criteria, 56 patients revealed CVS ; CVS was ruled oup in 19 patients showing near normal angiogram with negative spasm provocation test and in 5 patients with restion high degree fixed stenosis(luminal narrowing of 97+/-4%). Erg Echo could diagnose CVS before the angiography with the sensitivity of 91%(51/56,95% confidence interval [CI] ; 84-98%) and the specificity of 88%(21/24,95% CI ; 75-100%). Of 53 patients showing RWMA in Erg Echo, 42%(22/53) revealed no significant changes in the simultaneously recorded ECG and characteristic ST elevation was recorded in only 38%(20/53). There was no case of myocardial infarction or fatal arrhythmia during Erg Echo. CONCLUSION: Erg Echo befor the coronary angiography is safe and can e utilized as a reliable diagnostic screening test of CVS in patients with negative tradmill or normal stess myocardial perfusion scan, This finding suggests that invasive coronary angiography can be avioded in selected patients for the diagnosis of vasospastic angina.