Left atrial geometric and functional remodeling parameters by cardiac magnetic resonance imaging and outcome prediction in patients with severe aortic stenosis

BACKGROUND: Emerging studies are beginning to shape the role of afflicted left atrium’s (LA) function and strain in cardiovascular diseases including aortic stenosis (AS), especially for risk stratification and outcome prediction. Cardiac magnetic resonance imaging (CMR) is becoming increasingly useful in determining parameters of LA, however, in patients with AS, this has not been yet approached. AIMS: The study sought to evaluate the role of CMR in characterizing LA geometry and function in patients with severe AS. METHODS: We prospectively evaluated 70 patients with symptomatic severe AS and 70 controls. LA volumes, function and strain were determined using CMR. A composite outcome (cardiac death, ventricular tachyarrhythmias, and heart failure hospitalization) was evaluated over a median of 13 months. Time-to-event outcomes were analyzed accordingly. RESULTS: Besides increased LA volumes (LAVs) and LA sphericity index (LASI) (P <0.001), LA phasic functions and strain were considerably defective in patients with AS (all P <0.001). LV mass (LVM), end-diastolic and end-systolic volumes were also significantly associated withal LA strain parameters (P <0.001). Regarding outcome prediction, decreased total (LA-et), active (LA-ea) and passive strain (LA-ep), along with enhanced LASI were independently associated with outcome (P <0.001). Time-to-event analysis showed significantly higher risk to reach the composite outcome for LA-et <31.1% [HR=6.981; 95%CI (2.74–17.77), P <0.001)], LA-ep <14.5% [HR = 2.68; 95% CI (1.00–7.18), P<0.01)], and LA-ea <21.2% [HR = 2.02; 95% CI (1.07–3.83), P <0.03]. CONCLUSION: Patients with severe AS have significantly remodelled LA, with impaired phasic function and strain. Amongst all CMR parameters, LAVmin, LASI, LAPF and LA-ep appear to be independent predictors for outcome