Predictive value of echocardiographic left atrial size for incident stoke and stroke cause mortality: a population-based study

Abstract

Objectives: To investigate the associations between echocardiographic left atrial (LA) size and incident stoke and stroke cause mortality among a rural population in China.

Design: A prospective study.

Setting and participants: Based on the Northeast China Rural Cardiovascular Health Study, we selected a total of 10 041 participants aged ≥35 years who agreed to have transthoracic echocardiography at baseline and were successfully followed up for incident stoke and stroke cause mortality.

Primary outcome measure: The outcomes were stroke and stroke cause death according to medical records and death certificates during the follow-up period.

Results: LA enlargement (LAE) group had a higher prevalence of cardiovascular disease than normal LA diameter (LAD) group. After excluding individuals who had a prior stroke, subjects with LAE showed higher incident rates of stroke and its mortality in the overall and specific stratified analyses (all p<0.05). Kaplan-Meier analysis revealed that LAE could predict stroke incidence and stroke-free survival, but the association was no longer observed after the adjustment for potential confounding factors. Cox regression analysis reported that per 1 SD increment in LAD and LAD/body surface area (BSA) was associated with an increased incidence of stroke (LAD: HR=1.20, 95% CI 1.08 to 1.33, p<0.001; LAD/BSA: HR=1.22, 95% CI 1.11 to 1.35, p<0.001) and stroke cause mortality (LAD: HR=1.27, 95% CI 1.08 to 1.50, p<0.01; LAD/BSA: HR=1.41, 95% CI 1.20 to 1.65, p<0.001) in the total population, and similar trends were found in both genders (all p<0.05). LAD or LAD/BSA was related to ischaemic and haemorrhagic stroke incidence, and the risk of ischaemic and haemorrhagic stroke mortality (all p<0.05). The dose-response curves further suggested linear associations between LAD, LAD/BSA and the incidence of stroke and subsequent mortality in the general population (all p<0.05).

Conclusions: Our population-based study implied that LA size, especially LAD and LAD/BSA, might be useful echocardiographic biomarkers that had the potential to predict incident stroke and stroke cause mortality.

Keywords: cardiac epidemiology; echocardiography; epidemiology; stroke medicine.

Figure 1

Kaplan-Meier survival curves for stroke incidence (A) and stroke-free survival (B) in overall population according to LA size. LA, left atrial; LAE, LA enlargement.

Figure 2

Kaplan-Meier survival curves for stroke incidence in men (A) and women (B), and ischaemic (C) and haemorrhagic (D) stroke incidence according to LA size. LA, left atrial; LAE, LA enlargement.

Figure 3

Kaplan-Meier survival curves for stroke-free survival in men (A) and women (B), and ischaemic (C) and haemorrhagic (D) stroke-free survival according to LA size. LA, left atrial; LAE, LA enlargement.

Figure 4

Adjusted dose–response associations between LAD and the risk of stroke (A) and stroke cause mortality (B). Adjusted for age, gender, BSA, smoking, drinking, heart rate, history of CHD, history of AF, history of HF, history of heart valve diseases, hypertension, diabetes, medication for hypertension and diabetes, dyslipidaemia, eGFR, statin use, aspirin use, LVMI, LVEF, E/e′ as appropriate. The Y-axis indicates the ln(HR) of stroke for any value of LAD compared with the reference values. Dashed lines refer to the 95% CIs. AIC, Akaike information criterion; CL, confidence interval; LAD, left atrial diameter; BSA, body surface area; CHD, coronary heart disease; AF, atrial fibrillation; HF, heart failure; eGFR, estimated glomerular filtration rate; LVMI, left ventricular mass index; LVEF, left ventricular ejection fraction.

Figure 5

Adjusted dose–response associations between LAD/BSA and the risk of stroke (A) and stroke cause mortality (B). Adjusted for age, gender, BSA, smoking, drinking, heart rate, history of CHD, history of AF, history of HF, history of heart valve diseases, hypertension, diabetes, medication for hypertension and diabetes, dyslipidaemia, eGFR, statin use, aspirin use, LVMI, LVEF, E/e′ as appropriate. The Y-axis indicates the ln(HR) of stroke cause mortality for any value of LAD/BSA compared with the reference values. Dashed lines refer to the 95% CIs. AIC, Akaike information criterion; CL, confidence interval; LAD, left atrial diameter; BSA, body surface area; CHD, coronary heart disease; AF, atrial fibrillation; HF, heart failure; eGFR, estimated glomerular filtration rate; LVMI, left ventricular mass index; LVEF, left ventricular ejection fraction.