Association of left atrial structure and function and incident cardiovascular disease in patients with diabetes mellitus: results from multi-ethnic study of atherosclerosis (MESA)

AIMS: Diabetes mellitus (DM) is associated with the development of cardiovascular disease (CVD). Morphological changes in the left atrium (LA) may appear before symptoms. We aimed to investigate the association between cardiac magnetic resonance imaging (CMR) measured LA structure and function and incident CVD in asymptomatic individuals with DM. METHODS AND RESULTS: Tissue tracking CMR was used to measure LA size and phasic function (emptying fractions and strain) on all 536 Multi-Ethnic Study of Atherosclerosis (MESA) participants with DM and available CMR at baseline in 2000-2002. At the time of enrolment, all participants were free of clinically recognized CVD, which was defined as MI, resuscitated cardiac arrest, angina, stroke, heart failure, and atrial fibrillation. Cox regression was used to assess the association of LA parameters with incident CVD adjusted for traditional cardiovascular risk factors, LV mass, NT Pro-BNP and maximum LA volume. Kaplan-Meier curves, adjusted for traditional risk factors, were generated for each LA measurement for the 25% of participants with the most abnormal values versus the remaining 75%. After a mean follow up of 11.4 ± 3.4 years, 141 individuals developed CVD. Individuals with incident CVD (mean age 66 years, 66% male vs. mean age 64 years, 50% male) had larger maximum and minimum LA volume index (LAVI) (32.1 vs. 26.8 mm3/m2; 19.4 vs. 14.2 mm3/m2 respectively, P < 0.001 for both), and lower total, passive, and active EF than those without CVD (P < 0.01 for all). In the fully adjusted model, there was a significant association of minimum LAVI, LA total EF, LA passive EF and LA active EF with incident CVD (HR 1.12 per mm3/m2, P < 0.001; HR 0.95 per %, P < 0.001; HR 0.97 per %, P = 0.021; HR 0.98 per %, P < 0.027, respectively). CONCLUSIONS: CMR measured LA minimum volume and LA function as measured by emptying fraction are predictive of CVD in a diabetic multi-ethnic population free of any clinically recognized CVD at baseline.