Renal resistive index as a predictive factor of delayed graft function: A meta-analysis.

BACKGROUND

Delayed graft function represents a major complication of kidney transplantation, leading to high rates of short and long-term morbidity. The aim of the present meta-analysis is to assess the role of renal resistive index measurement in the post-transplant period and evaluate its efficacy in the prediction of delayed graft function.

METHODS

Medline, Scopus, Cochrane Central Register of Controlled Trials CENTRAL, Clinicaltrials.gov and Google Scholar databases were systematically searched. Statistical analysis was performed with Review Manager 5.3, R 3.4.3 and Open Meta-Analyst software.

RESULTS

Fourteen studies were included with a total of 2741 kidney recipients. Patients with delayed graft function presented significantly higher rates of elevated renal resistive index (Odds Ratio: 1.96, 95% CI: [1.37, 2.81]). Also, renal resistive index values were significantly higher in patients with delayed graft function compared both to those with slow (Mean Difference: 0.04, 95% CI: [0.01, 0.07]) and immediate (Mean Difference: 0.10, 95% CI: [0.07, 0.12]) graft function. The pooled sensitivity for the detection of delayed graft function was estimated at 47.2% (95% CI: [30.9, 64.2]), the specificity at 69.3% (95% CI: [54.1, 81.2]) and the area under the curve at 0.613.

CONCLUSIONS

The present meta-analysis suggests the promising role of renal resistive index evaluation early after kidney transplantation, since its high values were significantly associated with higher incidence of delayed graft function. Future large-scale studies should define the most appropriate cut-off value and should incorporate renal resistive index in combined models in order to achieve optimal predictive accuracy.