Background: DNA breaks detected largely by terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) are observed in the hearts of patients with diseases such as dilated cardiomyopathy (DCM).
Study objectives: To determine the prognostic value of TUNEL assays in cases of DCM.
Design, setting, and participants: DCM patients were selected from among patients who had undergone left ventricular (LV) biopsy during the period from 1994 to 2001 in our hospital. Of those, 46 (35 men and 11 women; mean [± SD] age, 58 ± 11 years) who were followed up for > 3 years after the undergoing the biopsy (mean follow-up period, 4.9 ± 2.0 years) or died during the follow-up period were entered into the present study. The myocardial apoptotic index was assessed in deparaffinized biopsy specimens that were stained using a conventional TUNEL assay. In addition, all surviving patients received a follow-up echocardiographic examination.
Results: Ten of the 46 biopsy specimens (22%) contained TUNEL-positive myocytes; their mean apoptotic index was 0.44 ± 1.05%. The apoptotic index showed no relation to cardiac functional parameters determined at the time of biopsy, however. Seven patients died during the follow-up period, and 19 of the surviving patients were readmitted to the hospital because of a worsening of their heart failure. There was no significant difference in the apoptotic indexes of biopsy specimens from the dead and surviving patients, or between the surviving patients who were readmitted to the hospital and those who were not. There was also no significant correlation between the apoptotic index and changes in the LV ejection fraction, LV end-diastolic diameter, or LV posterior wall thickness during follow-up.
Conclusion: The apoptotic index derived from TUNEL assays is not predictive of the prognosis of patients with DCM-induced heart failure.