Leakage of cardiac troponin I in aortic valve stenosis

Objective. Degeneration and death of cardiomyocytes contribute to the genesis of heart failure (HF) in aortic valve stenosis (AS). We studied whether the ongoing myocyte damage in AS can be detected from circulating cardiac troponin I (cTnI) concentrations. Design and setting. A cross-sectional cohort study in a university hospital. Subjects and methods. We examined 131 adult patients undergoing echocardiography and cardiac catheterization for isolated AS. Blood was sampled from the aortic root and, in a subset of 49 patients, also from the coronary sinus for the determination of cTnI using a sensitive immunoanalysis. Results. Seventy-three patients (56%) had detectable aortic cTnI (>= 5 ng L-1) with 30 of them (23% of the total group) having cTnI above the reference limit in healthy subjects (> 14 ng L-1). Patients with detectable cTnI had a higher prevalence of HF than those with undetectable cTnI (42% vs. 19%, P = 0.004). Plasma cTnI rose from the aorta to the coronary sinus by >= 5 ng L-1 in 13 of 49 patients with AS (27%) versus in none of 12 control patients free of structural heart disease (P = 0.044). AS patients with transcardiac cTnI gradients >= 5 ng L-1 had lower left ventricular (LV) ejection fractions than AS patients with gradients < 5 ng L-1 (mean +/- SD, 52 +/- 14% vs. 61 +/- 11%; P = 0.011). Conclusions. Detectable circulating cTnI is not uncommon in AS and shows a moderate association with the presence of HF. Leakage of cTnI into the coronary sinus associates with impairment of LV systolic function. Monitoring cTnI could provide a means to expose incipient clinical deterioration in AS.