Measuring serum aminoterminal type III procollagen peptide, 7S domain of type IV collagen, and cardiac troponin T in patients with idiopathic dilated cardiomyopathy and secondary cardiomyopathy

Abstract

Objective: To identify new prognostic indicators in idiopathic dilated cardiomyopathy (DCM) and secondary cardiomyopathy.

Design and patients: Serum concentrations of aminoterminal propeptides of type III procollagen and the 7S domain of type IV collagen (7S collagen)--which have recently been used as indicators of collagen matrix turnover in other diseases--and of cardiac troponin T were measured in 17 consecutive patients with DCM and in four patients with secondary cardiomyopathy (one associated with hyperthyroidism, two with chronic renal failure, one with amyloidosis), confirmed by endomyocardial biopsy. The correlation of these variables with short term prognosis was then assessed prospectively.

Results: 11 of the patients were positive for type III procollagen, 7S collagen, or troponin T even though their creatine kinase concentrations were within the normal range. These patients had a poor short term prognosis (p < 0.001).

Conclusions: Within the DCM and secondary cardiomyopathy groups, there was a subgroup of patients with raised concentrations of serum collagen and troponin T, for whom short term prognosis was poor. Although it is unclear whether these serum peptide levels reflect ongoing myocyte degeneration and interstitial fibrosis, they may serve as useful new prognostic indicators for cardiomyopathy.

Figure 1

Rate of freedom from cardiac events. The event-free rate in patients seronegative for type III procollagen, 7S collagen, or troponin T was significantly higher than in seropositive patients on day 216 (p < 0.001).