Ongoing Myocardial Injury in Stable Severe Heart Failure

The Pilot Randomized Study of Nesiritide Versus Dobutamine in Heart Failure (PRESERVD-HF)

Acute heart failure syndromes (AHFS) are related to several diseases affecting not only the heart but also the kidneys and blood vessels. Emerging evidence indicates that myocardial injury may also play a role in the pathophysiology of AHFS, as suggested by increased levels of markers of injury, such as cardiac troponin (cTn). Although cTn is a known prognostic marker, the release of cTn during hospitalization has not been evaluated prospectively with serial measures. We prospectively evaluated patterns of cTn release by conducting serial measures of cTnI and cTnT in patients hospitalized for AHFS. This study enrolled 51 patients with AHFS who were admitted with worsening heart failure (HF) and a history of coronary artery disease (CAD) in whom an acute coronary event was not suspected. Levels of cTnI and cTnT were measured at 8, 32, 56, and 80 hours after study entry. At baseline, 73.9% of patients had detectable cTnI, and 43.5% had detectable cTnT levels. The median concentrations of cTnI and cTnT were unchanged from 0 to 32 hours, increased from 32 to 56 hours, then either plateaued (cTnT) or decreased to baseline (cTnI). Of the 26 patients who had no detectable cTn levels at baseline, 2 (7.7%) developed detectable cTnT and 5 (41.7%) developed detectable cTnI release during hospitalization. Detectable levels of cTn at baseline were related to short-term clinical events. In this study of patients with CAD in whom an acute coronary event was not suspected, most had detectable levels of cTn present at admission, and some patients developed cTn release during hospitalization. Because cTn release may be a marker for myocardial injury, this study raises the possibility that injury occurred in most patients admitted with AHFS. Therefore, the goal of therapy for AHFS should be not only to improve symptoms and hemodynamics but also to salvage myocardium. Accordingly, therapies for AHFS that are aimed at improving hemodynamics may affect long-term prognosis by either injuring or salvaging myocardium.

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 (> or =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 > or =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 > or =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.