Pharmacologically Inducible Coronary Vasospastic Changes in Patient with Ischemic Heart Diseases with Normal Angiogram or Insignificant Coronary Lesion and Its Relationships with Risk Factors

ABSTRACT

BAKGROUND AND PURPOSES: Spasm of epicardial coronary arteries has been shown to play an important role in the pathogenesis of ischemic heart diseases. Spasm occurs in angiographically normal coronary arteries or arteries with organic atherosclerotic lesion and can result in rest angina, exertional angina or even myocardial angina or even myocardial infarction. However, pathogenetic mechanism of coronary artery spasm still remains unclear. The purpose of present study is to investigate characteristics of pharmacologically induced spasm of epicardial coronary artery in patient with ischemic heart disease with normal coronary angiogram or insignificant coronary artery disease (<25% narrowing), and to determine the relationship of coronary risk factors with coronary artery spasm in these patients group. METHODS: One hundred patients(male 47, female 53, age 19-75 years) with ischemic heart disease(stable angina, unstable angina, myocardial infarction) who had normal coronary angiogram or angiographically insignificant coronary artery stenosis(<25% narrowing) were included for pharmacological provocation test for coronary artery spasm. Acetylcholine(ACH) and Ergonovine(Erg) were given intracoronarily(IC) in incremental doses(Ach A1, 20micro, A2 50microg, A3 100microg and Erg E1 5microg, E2 10microg, E3 25microg) either into coronary artery concordant with ECG leads showing ischemic ST-T changes in exercise ECG and/or 24-hour ambulatory ECG, or otherwise into right coronary artery. Erg provocation test was done after completion of acetylcholine provocation test. Constriction of coronary artery by more than 50% induced by either or both of the drugs were analysed in terms of incidence, degree, location of spasm and relation to risk factors. Coronary vasodilatory reserve function was tested by IC Doppler method for those patients with no spasm of epicardial coronary artery but with chest pain and ST-segment changes during provocation test. Relationship of spasm with various risk factors were investigated. RESULTS: 1) Ach or Erg test were positivie in 50 patients(50%). Among 75 patients who were tested by both drug, both test were positive in 17 patients(22.6%), and negative in 39 patients(52%), and Ach test was positive but Erg test was negative in 15 patients(20%). The responses of Ach and Erg test were concordant in 75% of patients, the sensitivity and specificity of Ach test with reference to Erg test were 81% and 72%, respectively. 2) The characteristic features of spasm induced by Ach or Erg is focal narrowing in 34 patients and diffuse narrowing in 16 patients. The sites of spasm were LAD(23 cases), RCA(19 cases), LCX(5 cases), and in 3 cases, both LAD and LCX were narrowed. 3) In 50 patients showing no spasm, the typical chest pain or EKG changes was noted in 6 cases(12%). Of 6 patients, coronary vasodilatory reserve was decreased in 4 cases(66.7%). 4) Number of smoker was larger among spasm positive group(42%) than those among spasm negative group(12%)(p<0.01). CONCLUSION: The findings we observed in a limited series of patients suggest that in patients with normal or insignificant coronary angiogram, coronary spasm plays a role in the pathogenesis of broad spectrum of ischemic heart disease and that in patients with no coronary spasm but chest pain and ST-segment changes, coronary vasodilatory reserve is impaired, causing angina pectoris. Smoking may be one of the risk factors for coronary arterial spasm.