LONG-TERM EVOLUTION OF CARDIOMYOPATHY IN DIALYSIS PATIENTS

Background. Left ventricular enlargement is very common at the incepti on of dialysis therapy, and highly predictive of future cardiac morbid ity and mortality. It is not known whether cardiac size increases furt her while on dialysis therapy and whether potentially reversible risk factors for later progression can be identified. Methods. Baseline and yearly echocardiograms were performed in a prospective inception coho rt of 433 dialysis patients. The mean patient follow-up was 41 months; 29 patients had four consecutive echocardiograms at yearly intervals. Results. The patient subset with four echocardiograms was older (58 v s. 51 years, P = 0.02) and had a lower mass ventricular mass index (12 8 vs. 149 g/m(2), P = 0.02) than the parent group. Using repeated meas ures analysis of variance, applied to those with four echocardiograms, there were progressive increases over time in posterior wall thicknes s (P = 0.015), left ventricular end-diastolic diameter, left ventricul ar mass index (P = 0.001), and cavity volume index (P = 0.001). Mass-t o-volume ratios did not change. The biggest changes in mass (18 g/m(2) - 14%)and volume index (13 ml/m(2) - 18%) occurred between baseline a nd year 1, although increases in both were seen after year 1. Hemodial ysis versus peritoneal dialysis (41 g/m(2), P = 0.008) and anemia (10 g/m(2) per 1 g/dl drop in hemoglobin, P = 0.02) were associated with p rogressive left ventricular enlargement, but only within the first yea r of dialysis therapy. The left ventricular enlargement seen after yea r 1 was independent of anemia, blood pressure, serum albumin and mode of dialysis. Conclusions. Progressive cardiac enlargement, particularl y left ventricular dilation with compensatory hypertrophy, continues a fter starting dialysis therapy. Most of the additional cardiac enlarge ment seems to occur in the first year of dialysis therapy, suggesting that intervention beyond one year may be relatively ineffective.