Prevalence and prognostic significance of left ventricular myocardial late gadolinium enhancement in severe aortic stenosis.

BACKGROUND: Myocardial fibrosis occurs in aortic stenosis (AS) as part of the hypertrophic response. It can be detected by LGE, which is associated with an adverse prognosis in the form of increased mortality and morbidity.

OBJECTIVES: To assess the prevalence of LGE patterns using cardiac magnetic resonance (CMR) in severe AS patients and to study its prognostic significance.

METHODS: Patients enrolled into the study from June 2012 to November 2014. All the patients underwent CMR and various patterns of LGE studied. These patients if symptomatic were advised AVR and others were managed conservatively. All patients were followed up and watched for outcomes like mortality, heart failure/hospitalization for cardiovascular cause, fall in left ventricular ejection fraction (LVEF) ≥20% and arrhythmia.

RESULTS: A total of 109 patients (mean age-57.7±12.5yrs) underwent CMR with 63 males. These patients were followed up for a mean of 13 months. Among 38 patients who underwent AVR, 6 died (5-cardiovascular cause, 1-non cardiovascular). 71 patients were managed conservatively out of which 18 died (17-cardiovascular cause, 1-non cardiovascular cause). LGE patterns were seen in 46 patients (43%); mid myocardial enhancement was seen in 31.1% of cases (33 patients). No LGE pattern was seen in 57%(63 patients). Basal and mid regions were maximally involved with mid myocardial enhancement in 66% & 68.3% respectively. LV ejection fraction (p=0.002), peak aortic systolic velocity (p=0.01) and peak aortic systolic gradient (p=0.02) were the main predictors of LGE. Main predictors of primary outcome were NYHA class [OR- 13.4(2.8-26.1), p≤0.001], age- 62± 9.6yrs(p=0.001), EF simpson-50.9±13%(p≤ 0.001), LGE[OR 2.8 (1.27-6.47),p=0.01], number of segments involved [2.37±2.1,P≤0.001] & CMR LV mass (151.73±32gms, p=0.007). LGE predicted heart failure/hospitalization for cardiovascular cause [OR- 3.8(1.2-11.9), p=0.01] and fall in LVEF [OR- 5.8(1.5-22.5), p=0.005]. Patients with LGE had 2.87 times risk of adverse outcomes and patients with more than 3 segment LGE involvement had again increased chances for adverse outcomes.

CONCLUSIONS: LGE was detected by CMR in 43% of patients with severe AS. It predicted recurrent heart failure, hospitalization for cardiovascular cause and fall in LV ejection fraction. Our study has laid a path to larger prospective studies with long term follow up to assess the prognostic impact of CMR in patients with severe AS.