High-Sensitivity Troponin I Concentrations Are a Marker of an Advanced Hypertrophic Response and Adverse Outcomes in Patients With Aortic Stenosis
What are the prognostic implications of plasma cardiac troponin I (cTnI) concentrations in patients with aortic stenosis?
Plasma cTnI concentrations were measured in two patient cohorts using a high-sensitivity assay. First, in the Mechanism Cohort, 122 patients with aortic stenosis (median age 71, 67% male, aortic valve area 1.0 ± 0.4 cm2) underwent cardiovascular magnetic resonance and echocardiography to assess left ventricular (LV) myocardial mass, function, and fibrosis. Kaplan–Meier analysis was performed across tertiles of cTnI concentrations.
The indexed LV mass and measures of replacement fibrosis (late gadolinium enhancement) were associated with cTnI concentrations independent of age, sex, coronary artery disease, aortic stenosis severity, and diastolic function. In the separate Outcome Cohort, 131 patients originally recruited into the SALTIRE (Scottish Aortic Stenosis and Lipid Lowering Trial, Impact of REgression) study, had long-term follow-up for the occurrence of aortic valve replacement (AVR) and cardiovascular deaths. Over a median follow-up of 10.6 years (1,178 patient-years), 24 patients died from a cardiovascular cause and 60 patients had an AVR. Plasma cTnI concentrations were associated with AVR or cardiovascular death (hazard ratio, 1.77; 95% confidence interval, 1.22-2.55) independent of age, sex, systolic ejection fraction, and aortic stenosis severity.
The authors concluded that in patients with aortic stenosis, plasma cTnI concentration is associated with advanced hypertrophy and replacement myocardial fibrosis as well as AVR or cardiovascular death.
This study reports that plasma cTnI concentrations demonstrated a close association with the magnitude of LV hypertrophy and the presence of mid-wall myocardial fibrosis in patients with aortic stenosis. Furthermore, high-sensitivity plasma cTnI concentration showed an independent association with long-term risk of AVR or cardiovascular deaths. High-sensitivity troponin assays appear to hold promise as a future clinical tool for patients with aortic stenosis, and large-scale prospective studies are required to investigate the use of cTnI in the management and risk stratification of patients with aortic stenosis to help identify asymptomatic patients who may potentially benefit from early surgery.
Keywords: Hypertrophy, Left Ventricular, Kaplan-Meier Estimate, Troponin I
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