Serum carboxy-terminal propeptide of
procollagen type I or
PICP (a marker of
collagen type I synthesis) and carboxy-terminal telopeptide of
collagen type I or CITP (a marker of
collagen type I degradation) were measured in
heart failure patients at baseline and after 1 year of CRT. Patients were categorized as responders or non-responders if they increased the distance walked in 6 min by > or <10%, respectively. At baseline, the
PICP:CITP ratio, an index of the degree of coupling between
collagen type I synthesis and degradation was higher (P = 0.006) in responders than in non-responders. Whereas the
PICP:CITP ratio decreased (P= 0.000)
after treatment in responders, it remained unchanged in non-responders. Thus, at 1-year, the
PICP:CITP ratio was similar in the two groups of patients. A direct correlation (r = 0.289, P = 0.037) was found between the baseline
PICP:CITP ratio and the change in the distance walked in 6 min in all patients. Receiver operating characteristics curves showed that a cut-off value of 14.4 for the
PICP:CITP ratio provided 70% specificity and 63% sensitivity for the predicting response to CRT with a relative risk of 2.07 (95% confidence interval, 0.98-4.39).
CONCLUSION:
Collagen type I turnover influences the long-term response to CRT. In addition, the ability of CRT to restore the balance between
collagen type I synthesis and degradation is associated with a beneficial response.