Peritoneal thickening is not inevitable in long-term peritoneal dialysis and is associated with peritoneal transport characteristics: a two-centre sonographic study

BACKGROUND: The peritoneum is subject to alterations in the life-long course of peritoneal dialysis (PD). Studies of the parietal peritoneum by non-invasive ultrasonography in PD patients are limited. We hypothesize that a prolonged PD duration is associated with a thicker peritoneum on ultrasonography and alterations in Doppler indexes of mesenteric vessels. METHODS: We recruited two groups of patients, 18 who had >7 years of PD and 18 who had <12 months of PD. We excluded patients with active peritonitis, history of major abdominal surgery, cirrhosis or malignancy. We measured the sonographic thickness of the parietal peritoneum and Doppler indexes of mesenteric vessels by trans-abdominal ultrasonography at two PD units in Taiwan. RESULTS: We found no significant difference between two groups of PD patients in peritoneal thickness and in Doppler indexes. However, our univariate and multivariate analysis indicated that peritoneal thickness is associated with peritoneal transport characteristics (dialysate/plasma creatinine) but not with age, duration of dialysis, body height, body weight or Doppler index. The peritoneum is significantly thicker in rapid transporters than in slow transporters (RUQ: 0.59 +/- 0.40 mm versus 0.27 +/- 0.29 mm, P = 0.01; LUQ: 0.60 +/- 0.40 mm versus 0.27 +/- 0.32 mm, P = 0.016; LQ: 1.07 +/- 0.85 mm versus 0.48 +/- 0.53 mm, P = 0.026). In addition, rapid transporters have a marginally lower Doppler resistive index of the superior mesenteric artery (0.87 +/- 0.08 versus 0.90 +/- 0.10, P = 0.028). CONCLUSIONS: Our data showed that peritoneal thickening is not inevitable in long-term PD patients. Sonographic thickness in the parietal peritoneum is associated with transport characteristics. Rapid transporters have a significantly thicker peritoneum. The Doppler index of mesenteric vessels had no association with PD duration or transport characteristics. Trans-abdominal ultrasonography is non-invasive and useful in evaluating peritoneal characteristics of PD patients.