Dynamic assessment of myocardial involvement in patients with end‐stage renal disease by ultrasonic tissue characterization and serum markers of collagen metabolism

BACKGROUND: Congestive heart failure is the most common cause of mortality in patients with end-stage renal disease (ESRD). However, noninvasive assessment for cardiac involvement in ESRD has not been established. HYPOTHESIS: Assessment of ultrasonic tissue characterization and serum markers of collagen degradation is useful for defining myocardial involvement in ESRD. METHODS: Cyclic variation of ultrasonic integrated backscatter of the ventricular septum (CV-IBS) and the serum levels of free matrix metalloproteinase-I (MMP-I) and tissue inhibitor of metalloproteinase-I (TIMP-I) were measured in 30 patients with ESRD undergoing routine hemodialysis (HD) and in 40 patients with essential hypertension (HTN). RESULTS: Compared with the group with HTN, ESRD (before HD) showed larger left ventricular (LV) mass index (217 +/- 56 vs. 146 +/- 45 g/m2, p < 0.01), worse LV diastolic function (E/A, 0.6 +/- 0.2 vs. 0.9 +/- 0.3, p < 0.05), smaller CV-IBS (9.0 +/- 1.3 vs. 12.4 +/- 0.9 dB, p < 0.01), and larger TIMP-I/MMP-I (46 +/- 10 vs. 34 +/- 10, p < 0.05), in spite of the comparable ventricular wall thickness. Thus, these indices may possibly reflect myocardial interstitial fibrosis. After HD (after the improvement of myocardial interstitial edema), a negative linear relationship between CV-IBS and TIMP-I/MMP-I was observed (r= -0.52, p < 0.05). CONCLUSIONS: Noninvasive assessment of ultrasonic tissue characterization and serum markers of collagen type I degradation may be a new diagnostic tool for defining myocardial interstitial fibrosis in patients with ESRD and LV hypertrophy.