Prognostic Value of Modified Haller Index in Patients with Suspected Coronary Artery Disease Referred for Exercise Stress Echocardiography

BACKGROUND: The influence of chest conformation on outcome of patients with suspected coronary artery disease (CAD) is actually unknown. MATERIALS AND METHODS: This retrospective study included all consecutive patients who underwent exercise stress echocardiography (ESE) for suspected CAD at our institution between February 2011 and September 2019. Modified Haller index (MHI; chest transverse diameter over the distance between sternum and spine) was assessed in all patients. Obstructive CAD was diagnosed by ≥70% stenosis in any epicardial coronary artery. During the follow-up time, we evaluated the occurrence of any of the following: (1) cardiovascular (CV) hospitalizations and (2) cardiac death or sudden death. RESULTS: A total of 1091 consecutive patients (62.4 ± 12.6 years, 57.2% of men) were included in the study. Patients with normal chest shape (MHI ≤2.5) and those with concave-shaped chest wall (MHI >2.5) were separately analyzed. A positive ESE was diagnosed in 171 patients of which 80.7% had an obstructive CAD (true positive), while 19.3 not (false positive [FP]). Majority of FP ESE (70.9%) derived from concave-shaped chest wall group. During follow-up time (2.5 ± 1.9 years), 9 patients died and 281 were hospitalized because of heart failure (163), acute coronary syndromes (39), and arrhythmias (79). At the multivariate Cox regression analysis, age (heart rate [HR]: 1.02, 95% confidence interval [CI]: 1.01-1.03), MHI >2.5 (HR: 0.39, 95% CI: 0.26-0.56), diabetes mellitus (HR: 4.89, 95% CI: 3.78-6.32), horizontal ST depression ≥1 mm (HR: 2.86, 95% CI: 1.98-4.15), peak exercise average E/e' ratio (HR: 1.08, 95% CI: 1.06-1.10), and peak exercise wall motion score index (HR: 1.79, 95% CI: 1.36-2.35) were independently correlated with outcome. CONCLUSIONS: Patients with concave-shaped chest wall (MHI >2.5) have a significantly lower probability of CV events than those with normal chest shape (MHI ≤2.5) over a medium-term follow-up. A noninvasive chest shape assessment could identify subjects at lower risk of CV events.