Is Indexed Left Atrial Volume (LAVi) in Indian Patients with Acute Coronary Syndrome (ACS) Undergoing Revascularization a Predictor of Cardiovascular Outcomes?

BACKGROUND: Left atrial volume indexed to body surface area (LAVi) is the recommended method for LA size quantification. Assessing LAVi in Indian patients undergoing coronary interventions for acute coronary syndrome (STEMI, NSTEMI, and UA) is clinically relevant. METHODS AND RESULTS: Amongst 190 patients (66.4 yrs, 68.4% males), 29.5%, 40.5%, and 30% respectively had STEMI, NSTEMI and UA. Mean LAVi was 32.29 ± 12.06 ml/m(2) and 111 (58.4%) had LAVi ≥32 while 79 (41.6%) had LAVi <32. Patients were divided into 2 groups (group 1 LAVi >32 and group 2 LAVi <32). Group 1 patients had higher prevalence of TVD [n = 49 vs n = 5, p = <0.001] and higher mean Syntax score (24.47 vs 14.64, p = <0.001). Despite similar LVEF, those with higher LAVi had had higher incidence of mild MR (50.4 vs 27.8, P = 0.0002) and moderate/severe MR was present only in Group 1 patients (27.9% and 5.4%). Grade I, II, and III diastolic dysfunction was present in 71.2, 17.1, and 9.9% patients in Group 1 vs 45.6%, 0%, and 0% in group 2. Diastolic parameters like septal E/e' and lateral E/e'ratio were also higher in Group 1. Major adverse cardiovascular events (MACE) at 30 days was significantly higher in group 1 (20.7 vs 6.3%, P = 0.006). On multivariate analysis, triple vessel disease and LAVi were the only predictors of MACE while LVEF was not. ROC curve analysis for LAVi demonstrated that a cut-off 33.35 ml/m2, predicted 30 day MACE with Area under curve ( AUC) 0.775 (95% CI 0.700-0.850); sensitivity and specificity of 86.7% and 61.4%. Inter-quartile analysis of LAVi (<26.3, 26.3-33.35, 33.36-36.3, and >36.3 ml/m2) demonstrated that 30 day MACE increased across quartiles (4.16%, 4.25%, 22.44%, and 28.26%, respectively, P < 0.001). CONCLUSION: Amongst patients with ACS undergoing revascularization, those with higher LAVi had more severe CAD, diastolic dysfunction and higher 30 day MACE. LAVi provides superior prognostic information as compared to conventional LV systolic and diastolic parameters in patients with ACS and should be incorporated in routine echocardiographic analysis. More studies with larger numbers and longer follow up are required to further elucidate on this.