Clinical relevance of coronary risk classification and reclassification with coronary artery calcium score in asymptomatic people living with diabetes. An observational study
Résumé
Aims
To explore (i) in what proportion and direction coronary artery calcium (CAC) score reclassifies coronary risk in asymptomatic diabetic patients at high a priori coronary risk, and (ii) whether screening for asymptomatic myocardial ischemia / coronary stenosis only in patients at very high coronary risk - whether a priori or combined with those reclassified at very high risk according to their CAC score - has good sensitivity to detect these conditions.
Methods
We retrospectively selected 377 asymptomatic primary prevention diabetic patients at high or very high a priori coronary risk according to national guidelines. All had their CAC score measured and underwent stress myocardial scintigraphy to detect myocardial ischemia. Those identified with ischemia then had a coronary angiography to identify coronary stenoses.
Results
Of the selected patients, 242 and 135 patients had a high and very high a priori coronary risk, respectively. After taking into account their CAC score, the former were reclassified into three risk categories: moderate (n = 159, 66%), high (n = 38) and very high (45 patients) risk.
Myocardial ischemia was identified in 35 patients and coronary stenoses in 14 of the latter. Had a stress scintigraphy been performed only in the 135 patients at very high risk a priori, 18 patients would have been detected with ischemia (sensitivity 51%), and 9 with coronary stenoses (sensitivity 64%). Had a scintigraphy also been performed on the 45 patients at very high risk after CAC-reclassification, an additional 7 and 5 patients with ischemia and coronary stenoses, respectively, would have been identified.
Conclusion
Following national guidelines, 66% of our population of asymptomatic diabetic persons at high a priori coronary risk were reclassified into the moderate risk category, translating into less stringent goals for risk factor control. Eighteen percent were reclassified into the very high-risk category, leading to 100% detection sensitivity for patients with ischemia and coronary stenoses.