Clinical variables associated with the presence of inflammatory infiltrates in patients with dilated cardiomyopathy undergoing heart transplantation.

INTRODUCTION

Idiopathic dilated cardiomyopathy (DCM) is, together with ischemic heart disease, the major cause of end-stage heart failure leading to heart transplantation. However, an unknown percentage of patients with this diagnosis has inflammatory foci found in the histopathological study of the explanted heart. This fact suggests an undetected process of acute myocarditis as the cause of cardiac dysfunction.

OBJECTIVE

The objective of this study was to identify clinical and echocardiographic variables related to the presence of myocardial infiltrates, as a potential guide to determine which patients should undergo endomyocardial biopsy in DCM.

MATERIALS AND METHODS

We retrospectively analyzed 161 patients who underwent heart transplantation with a diagnosis of DCM between 1987 and 2007. The presence of inflammatory infiltrates was considered significant when the histopathological study of tissue blocks from the left ventricle showed 1 or more foci per cm(2) of perivascular or interstitial mononuclear or polymorphonuclear cells, whether or not in the presence of cytolysis.

RESULTS

Seventeen patients (11%) had these inflammatory histological findings; of them, 6 (35%) showed preponderance of eosinophils and 7 (41%) showed areas of cytolysis. The DCM group with inflammatory infiltrates showed significant differences in terms of younger age (45 +/- 15 vs 50 +/- 11 years; P < .01) and smaller ventricular diameters (P < .05). Male gender was more frequent in this group, and the patients had a poorer clinical status and greater dependence on inotropic drugs.

CONCLUSIONS

Inflammatory infiltrates are frequently present in DCM explanted hearts. Although there are no relevant clinical variables to identify subclinical myocarditis, these patients are younger and have smaller ventricular diameters and poorer functional status at the time of transplantation.