Cardiac magnetic resonance correlates of staging algorithm in patients with asymptomatic severe aortic stenosis

Abstract

Abstract Background The staging algorithm recently proposed to risk stratify patients with severe aortic stenosis (AS) has not been largely applied to patients who are asymptomatic. While the presence of severe tricuspid regurgitation, pulmonary hypertension and right ventricular dysfunction (stages 3-4) is expected to be low, the prevalence of left ventricular damage (LV), mitral regurgitation, left atrial (LA) dilation and atrial fibrillation (stages 1-2) can be higher in patients with asymptomatic severe AS. The cardiac magnetic resonance (CMR) correlates of the staging algorithm have not been described. Purpose To investigate the distribution of patients with asymptomatic severe AS in the staging algorithm and its differences with CMR findings. In addition, differences in CMR data between patients presenting with AS-related adverse events at 1-year follow-up and patients free of events were compared. Methods Patients with asymptomatic severe AS (aortic valve area, AVA<1.0 cm2) and preserved LV ejection fraction (EF) (>50%) that were referred to CMR were included. Biomarkers, echocardiographic and CMR data were assessed retrospectively. CMR-derived parameters included LV and right ventricular (RV) volumes and systolic function, LA volumes and tissue characterization were reported at baseline and compared with AS-related events (a composite of all-cause mortality, symptoms onset, or need for aortic valve replacement) during 1-year follow-up. Results Of 97 patients included (73±9 years old; 36% males), 3 (%) patients were classified in Stage 0, 34 (35%) in Stage 1, 59 (61%) in Stage 2, and 1 (1%) in Stage 3 or 4. Compared to stage 1, patients in stage 2 were older (P=0.006) and had a higher prevalence of overweight (P=0.037), hypertension (P=0.018), NT-proBNP (P=0.030) and hsTnT (p=0.011) levels. On CMR, they showed higher LV volumes and mass index, larger LA volumes and reduced LA ejection fraction, but no differences on myocardial tissue characteristics (Table 1). Regarding prognosis, 45 (46.5%) patients presented AS-related events at 1-year follow-up. Those with events were mainly in stage 2 (36%) and presented higher NT-proBNP levels despite showing no differences in AVA. On CMR, those with events had lower LVEF, greater LV to RV end-diastolic volume ratio, greater left atrio-ventricular coupling index, reduced LA function and a higher extension of late gadolinium enhancement (Table 2). Conclusions In our cohort, most patients with severe asymptomatic AS were in stage 2. Stage 2 patients presented a higher degree of left-chambers remodelling on CMR compared to patients in stage 1. Patients in stage 2 or with lower LVEF, LV remodelling or reduced LAEF on CMR were those with an increased risk for events at follow-up.