Impact of intra-abdominal pressure on early kidney transplant outcomes

Abstract

Increased intra-abdominal pressure (IAP) is common among post-surgical patients and may cause organ dysfunction. However, its impact after kidney transplantation on early postoperative complications and graft recovery remains unclear. We designed a prospective, observational cohort study to describe the prevalence and determinants of IAP, as well as its effect on delayed graft function, postoperative complications, and graft recovery. IAP was measured in 205 kidney transplant recipients every 8 h during the first 72 h after surgery using the urinary bladder technique. Intra-abdominal hypertension was defined as IAP ≥ 12 mmHg. Patients were followed for 6 months or until graft failure/death. Mean IAP was 12 ± 3.3 mmHg within the first 24 h. 78% of subjects presented with intra-abdominal hypertension during the first 72 h. Increased IAP was associated with higher renal resistive index [r = 0.213; P = 0.003] and lower urine output [r = - 0.237; P < 0.001]. 72 h mean IAP was an independent risk factor for delayed graft function [OR: 1.31; 95% CI: 1.13-1.51], postoperative complications [OR: 1.17; 95% CI: 1.03-1.33], and absence of graft function recovery [HR for graft function recovery: 0.94; 95% CI: 0.88-0.99]. Increased IAP was highly prevalent after transplantation and was independently associated with delayed graft function, postoperative complications, and absence of graft function recovery. Routine IAP monitoring should be considered post-transplantation to facilitate early recognition of relevant complications.

Figure 1

Study flow chart. IAH intra-abdominal hypertension.

Figure 2

Association between Day-0 intra-abdominal pressure (IAP), renal resistive index (RRI), Day-0 mean arterial pressure, Day-0 fluid balance and Day-0 urine output. RRI (measured by Doppler ultrasound) and Day-0 urine output showed significant associations with Day-0 IAP (measured by the bladder method). No association of day-0 IAP with Day-0 mean arterial pressure and Day-0 fluid balance was evident.

Figure 3

Stratification of renal resistive index (RRI) according to intra-abdominal hypertension (IAH) grade in renal transplant recipients. Subjects with IAH grades II/III presented significantly higher RRI (Kruskal–Wallis test). Overall: H = 8.01; P = 0.018. Male recipients (red): H = 3.18; P = 0.204. Female recipients (blue): H = 5.68; P = 0.058.

Figure 4

Kaplan–Meier plots of graft function recovery in patients stratified by intra-abdominal hypertension (IAH) grade.