Prognostic value of echocardiographic calcium score in patients with a clinical indication for stress echocardiography

Abstract

Objectives: The value of the echocardiographic calcium score (eCS) was evaluated to predict cardiac events in a multicenter cohort of subjects without known coronary disease, who underwent stress echocardiography (SE) for suspected coronary artery disease (CAD).

Background: Several studies have established that aortic valve sclerosis and/or calcification and mitral calcification, as detected by echocardiography, predict cardiovascular morbidity and mortality. The use of a semiquantitative total cardiac calcium score (eCS) to assess aortic and mitral valves, papillary muscles, and the ascending aorta has never been tested in multicenter studies; the inherent subjectivity and clinical applicability of such a parameter remains a concern.

Methods: We identified 1,303 patients from 5 Italian institutions and 1 U.S. institution, who had no known CAD and who underwent clinically-indicated pharmacological or exercise SE. They were followed up for myocardial infarction (MI) and all-cause death. eCS was assessed from archived images, and its discrimination and reclassification prognostic potential was determined.

Results: Fifty-eight patients met the combined endpoint of all-cause death (n = 37; 2.8%) or MI (n = 21; 1.6%) during a median follow-up of 808 days. Age, diabetes mellitus, eCS >0, and ischemic SE were multivariate predictors of hard events. Kaplan-Meier curves demonstrated that patients with ischemic SE or eCS >0 had worse outcomes. When both variables were abnormal, the prognosis was worse (p < 0.001). The multivariate model demonstrated that both eCS and ischemic SE independently contributed to risk prediction more than clinical variables. Both wall motion during SE and eCS were able to significantly reclassify the risk of events, but only stress wall motion demonstrated an incremental discrimination value.

Conclusions: eCS demonstrated significant prognostic value in predicting hard cardiac events in a multicenter population of patients who required noninvasive evaluation. Its value was independent from clinical assessment and wall motion during SE, although it did not show incremental value over these factors for discrimination of patients with and without events.

Keywords: calcium score; cardiac events; echocardiography; prognosis; stress echocardiography.