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Simultaneous multivessel coronary artery spasm demonstrated by quantitative analysis of thallium-201 single photon
K Kugiyama1, H Yasue, K Okumura
1Division of Cardiology, Kumamoto University School of Medicine, Japan.
Insights
Multivessel coronary artery spasm causes variant angina attacks. This condition leads to more severe, prolonged myocardial ischemia and a higher risk of dangerous arrhythmias compared to single-vessel spasm.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Variant angina (Prinzmetal's angina) is characterized by coronary artery spasm.
- Coronary arteriography may show normal or near-normal findings in patients with variant angina.
- The extent and clinical implications of multivessel spasm in variant angina require further elucidation.
Purpose of the Study:
- To investigate the characteristics and consequences of coronary artery spasm in patients with variant angina.
- To differentiate the effects of multivessel versus single-vessel coronary artery spasm.
Main Methods:
- Thallium-201 myocardial scintigraphy with quantitative emission computed tomography.
- Coronary arteriography to assess coronary artery anatomy and spasm.
- Analysis of electrocardiographic changes (ST-segment elevation) and arrhythmias during angina episodes.
Main Results:
- Multivessel coronary artery spasm (2+ arteries) was associated with more extensive and severe myocardial perfusion defects compared to single-vessel spasm.
- Patients with multivessel spasm experienced longer durations of ST-segment elevation.
- Higher incidence of ventricular arrhythmias and atrioventricular block was observed in patients with multivessel spasm.
- Nifedipine administration abolished angina attacks and perfusion defects.
Conclusions:
- Multivessel coronary artery spasm is a significant factor in variant angina, causing more severe myocardial ischemia.
- Simultaneous multivessel spasm leads to prolonged ischemia and increased risk of serious arrhythmias.
- Pharmacological intervention, such as nifedipine, effectively manages variant angina by preventing coronary spasm.
Abstract:
Thallium-201 myocardial scintigraphy with quantitative analysis of emission computed tomography was performed during episodes of angina in 19 patients with variant angina and nearly normal coronary arteriographic findings. Eleven patients (group I) were shown by arteriography to have spasm in 2 or more large coronary arteries. Eight patients (group II) had spasm in only 1 coronary artery. In 7 patients in group I, significant diffuse perfusion defects simultaneously appeared in multiple coronary artery regions on the scintigram (group IA). The extent and severity of the perfusion defect as measured by thallium-201 tomography were significantly greater in group IA than in group II (p less than 0.001 and p less than 0.01, respectively). The duration of transient ST-segment elevation during the attack in group IA was significantly longer than in group II (p less than 0.001). The incidence of ventricular arrhythmias, including ventricular tachycardia, or complete atrioventricular block during the anginal attack was significantly higher (p less than 0.05) in group IA than in group II. In all study patients, neither attack nor scintigraphic perfusion defect appeared on the repeat test after oral administration of nifedipine. In conclusion, multivessel coronary artery spasm simultaneously appears and causes the attack in many patients with variant angina and nearly normal coronary arteriographic findings, and myocardial ischemia due to simultaneous multivessel coronary spasm is likely to be more extensive and severe, persist longer and have a higher frequency of potentially dangerous arrhythmias than that due to spasm of only 1 coronary artery.