Adverse prognosis associated with asymmetric myocardial thickening in aortic stenosis

Abstract

Aims: Asymmetric wall thickening has been described in patients with aortic stenosis. However, it remains poorly characterized and its prognostic implications are unclear. We hypothesized this pattern of adaptation is associated with advanced remodelling, left ventricular decompenzation, and a poor prognosis.

Methods and results: In a prospective observational cohort study, 166 patients with aortic stenosis (age 69, 69% males, mean aortic valve area 1.0 ± 0.4 cm2) and 37 age and sex-matched healthy volunteers underwent phenotypic characterization with comprehensive clinical, imaging, and biomarker evaluation. Asymmetric wall thickening on both echocardiography and cardiovascular magnetic resonance was defined as regional wall thickening ≥ 13 mm and > 1.5-fold the thickness of the opposing myocardial segment. Although no control subject had asymmetric wall thickening, it was observed in 26% (n = 43) of patients with aortic stenosis using magnetic resonance and 17% (n = 29) using echocardiography. Despite similar demographics, co-morbidities, valve narrowing, myocardial hypertrophy, and fibrosis, patients with asymmetric wall thickening had increased cardiac troponin I and brain natriuretic peptide concentrations (both P < 0.001). Over 28 [22, 33] months of follow-up, asymmetric wall thickening was an independent predictor of aortic valve replacement (AVR) or death whether detected by magnetic resonance [hazard ratio (HR) = 2.15; 95% confidence interval (CI) 1.29-3.59; P = 0.003] or echocardiography (HR = 1.79; 95% CI 1.08-3.69; P = 0.021).

Conclusion: Asymmetric wall thickening is common in aortic stenosis and is associated with increased myocardial injury, left ventricular decompenzation, and adverse events. Its presence may help identify patients likely to proceed quickly towards AVR.

Clinical trial registration: https://ichgcp.net/clinical-trials-registry/NCT01755936: NCT01755936.

© The Author 2017. Published by Oxford University Press on behalf of the European Society of Cardiology

Figures

Figure 1

Asymmetrical wall thickening on both magnetic resonance and echocardiography. Images demonstrating asymmetric wall thickening in patients with aortic stenosis. Cardiovascular magnetic resonance short-axis cine images showing an abnormally thickened septum: in a patient with asymmetric remodelling (A) and two subjects with asymmetric hypertrophy (B) and (C). Echocardiographic parasternal long-axis images demonstrating thickening of the septum in two further patients with asymmetric remodelling (D) and (E). Echocardiographic apical 4-chamber image in a subject with asymmetric hypertrophy (F).

Figure 2

Prevalence, distribution, and resolution after aortic valve replacement of asymmetric wall thickening. (A) Seventeen segment model of the LV demonstrating the site of asymmetric wall thickening as detected by both magnetic resonance and echocardiography. Magnetic resonance was more sensitive in detecting asymmetric wall thickening (43 cases) than echocardiography (29 cases). On both modalities, asymmetric wall thickening was almost universally confined to the basal and mid-cavity segments of the septum. (B) Patient with asymmetric wall thickening at baseline, which resolved when magnetic resonance was repeated 1 year after aortic valve replacement.

Figure 3

Characteristics of patients with asymmetric vs. concentric wall thickening. Boxplots presenting: aortic valve area (A), indexed left ventricular mass (B), high sensitivity cardiac troponin I (C) and brain natriuretic peptide (D) concentrations in aortic stenosis patients with asymmetric and concentric patterns of wall thickening. Despite no difference in AVA and left ventricular mass index (P = 0.15 and P = 0.49, respectively) patients with asymmetric wall thickening had higher cardiac troponin and BNP levels than those with concentric wall thickening (P < 0.001).

Figure 4

Outcome data in aortic stenosis patients with and without asymmetric wall thickening. Kaplan–Meier event estimates by adaptation patterns for the occurrence of death and AVR in aortic stenosis patients. Asymmetric thickening was associated with worse cardiac outcomes both when detected using magnetic resonance (A) (HR = 2.15 (1.29–3.59); P = 0.003) and echocardiography (B) (HR = 1.79 (1.08–3.69); P = 0.021). Perioperative complications in aortic stenosis patients undergoing aortic valve replacement. Subjects with asymmetric wall thickening had more cardiac complications in the perioperative period than those without based upon both magnetic resonance (C) 55% vs. 13% (P = 0.004) and echocardiographic (D) 57% vs. 19% (P = 0.023) assessments.