Prognostic Stratification of Patients With Vasospastic Angina: A Comprehensive Clinical Risk Score Developed by the Japanese Coronary Spasm Association
Can a comprehensive clinical risk score for vasospastic angina (VSA) patients be developed?
The present study aimed to develop a comprehensive clinical risk score for VSA patients. The patient database of the multicenter registry study by the Japanese Coronary Spasm Association (JCSA) (n = 1,429; median 66 years; median follow-up of 32 months) was utilized for score derivation. Positive diagnosis of provocative spasm was defined as total or subtotal (>90%) coronary artery narrowing induced by pharmacological (e.g., acetylcholine and ergonovine) or nonpharmacological (e.g., hyperventilation) challenge during coronary angiography, accompanied by chest pain and/or ischemic electrocardiogram (ECG) changes. The definition of spontaneous attack was an angina at rest and/or effort, accompanied by a transient ST-segment elevation or depression of more than 0.1 mV or a new appearance of negative U wave on ECG. The criterion of spontaneous attack was applied when the patients did not have significant organic coronary stenosis that could explain their angina attacks.
Mean age was 66 years, 76% were men, and 59% were smokers. Angina at rest was present in 50%, 21% had ST elevation and 9% ST depression, 61% had no coronary stenosis, and 25% had nonsignificant and 14% significant stenosis. Spasm-positivity by provocation occurred in more than 50%. Treatment included calcium channel blockers in 93%, nitrates in 49%, antiplatelets in 47%, statins in 33%, and beta-blockers in 4%. Multivariable Cox proportional hazard model selected seven predictors of major adverse cardiac events (MACE). The integer score was assigned to each predictor proportional to their respective adjusted hazard ratio: history of out-of-hospital cardiac arrest (4 points), smoking, angina at rest alone, organic coronary stenosis, multivessel spasm (2 points each), ST-elevation during angina and beta-blocker use (1 point each). According to the total score in individual patients, three risk strata were defined: low (score 0-2, n = 598), intermediate (score 3-5, n = 639), and high (score 6 or more, n = 192). The incidence of MACE in the low-, intermediate-, and high-risk patients was 2.5%, 7.0%, and 13.0%, respectively (p < 0.001). Cox model for MACE between the three risk strata also showed prognostic utility of the scoring system in various clinical subgroups. The average prediction rate of the scoring system in the internal training and validation sets was 86.6% and 86.5%, respectively.
The authors concluded that the novel scoring system, the JCSA risk score, may provide a comprehensive risk assessment and prognostic stratification for VSA patients.
The criteria for VSA in this database from Japan was rigorous, including the degree of angiographic stenosis that had to be accompanied by pain and ECG changes. The prevalence of vasospastic angina seems to have decreased over the past decades. The reason is not clear, but potentials include a decrease in smoking, increase in use of low-nicotine cigarettes, and increase in use of statins. Nevertheless, it is a serious problem for which the risk assessment tool will be helpful to clinicians.
Keywords: Japan, Spasm, Follow-Up Studies, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Electrocardiography, Calcium Channel Blockers, Prognosis, Hyperventilation, Proportional Hazards Models, Coronary Angiography, Chest Pain, Nitrates
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