Common causes of troponin elevations in the absence of acute myocardial infarction: incidence and clinical significance

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.

Gene expression profiles of Mst1r-deficient mice during nickel-induced acute lung injury

Previous studies have shown that mice deficient in the tyrosine kinase domain (TK-/-) of the receptor Mst1r have an increased susceptibility to nickel (Ni)-induced acute lung injury (ALI). Mst1r TK-/- mice have decreased survival times, alterations in cytokine and nitric oxide regulation, and an earlier onset of pulmonary pathology compared with control mice, suggesting that Mst1r signaling, in part, may regulate the response to ALI. To examine the role of Mst1r in ALI in more detail, we compared the gene expression profiles of murine lung mRNA from control and Mst1r TK-/- mice at baseline and after 24 h of particulate Ni sulfate exposure. Microarray analyses showed a total of 343 transcripts that were significantly changed, either by Ni treatment, or between genotypes. Genes responsible for inflammation, edema, and lymphocyte function were altered in the Mst1r TK-/- mice. Interestingly, the genes for several granzymes were increased in Mst1r TK-/- mice before Ni exposure, compared with controls. In addition, the Mst1r TK-/- lungs showed clusters of cells near the vascular endothelium and airways. Immunohistochemistry indicates these clusters are composed of macrophages, T cells, and neutrophils, and that the clusters display granzyme protein production. These results suggest that Mst1r signaling may be involved in the regulation of macrophage and T-lymphocyte activation in vivo during injury. This assessment of gene expression indicates the importance of genetic factors in contributing to lung injury, and points to strategies for intervention in the progression of inflammatory diseases.

Pericarditis

Pericarditis (inflammation of the pericardium) may be caused by infectious agents, autoimmune disorders, metabolic conditions, or malignancy, or it may be a complication of drug therapy, trauma, cardiac surgery, or smallpox vaccination. Diagnosis, based on clinical findings, electrocardiographic changes, chest radiograph, and ultrasound, may be confirmed as appropriate by pericardiocentesis. Although contemporary imaging technologies, such as computed tomography and magnetic resonance imaging, are useful, echocardiography remains the simplest and most expeditious noninvasive tool to assess inflammatory and infectious diseases of the pericardium. Although contemporary management of pericardial disease remains relatively unchanged, reports of innovative approaches to the management of pericardial effusion include the installation of intrapericardial thrombolytic agents to facilitate drainage of purulent effusions or balloon pericardiotomy for recurrent effusions. Both offer potential alternatives to the surgical pericardial window.

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.

Troponin I elevation in a patient with acute severe bronchospasm

Right ventricular strain is a source of troponin elevation in some patients with acute pulmonary embolism. Acute and/or severe obstructive airway disease could lead to a sudden increase in pulmonary arterial pressure and right ventricular afterload. We report a case of troponin I elevation in a 40-year-old woman who presented with acute severe bronchospasm and had a negative evaluation for coronary artery disease.

Circulating cardiovascular markers and mediators in acute illness: an update

An update is given of the circulating markers and mediators of cardiovascular dysfunction in acute illness. Some of these circulating markers reflect mediator action on the peripheral vasculature, such as endothelium-derived endothelin and nitrite/nitritate, the stable end products of nitric oxide. Other markers mainly reflect actions on the heart, such as the natriuretic peptide family, released from the heart upon dilatation, serving as a marker of congestive heart failure and potentially having negative inotropic effects. Indeed, some factors may be both markers as well as mediators of cardiovascular dysfunction of the acutely ill and bear prognostic significance. Assessing circulating levels may help refine clinical judgment of the cardiovascular derangements encountered at the bedside, together with clinical signs and hemodynamic variables. For instance, assessing natriuretic peptides in patients with pulmonary edema of unclear origin may help to diagnose congestive heart failure and cardiogenic pulmonary edema, when the pulmonary capillary wedge pressure is not measured or inconclusive. Future aligning of hemodynamic abnormalities with patterns of circulating cardiovascular markers/mediators may help to stratify patients for inclusion in studies to assess the causes, response to therapy and prognosis of cardiovascular derangements in the acutely ill.