Use of Intraoperative Duplex Ultrasound and Resistance Index Reduces Complications in Living Renal Donor Transplantation

Systematic review of intra-operative duplex scanning during renal transplantation

INTRODUCTION

A systematic review of the value of intra-operative duplex scanning during renal transplantation was undertaken.

METHODS

Studies assessing intra-operative renal cortical flow in the arcuate vessels with outcomes of ultrasound directed interventions during the initial procedure, delayed graft function, post-operative resistive indices, graft losses and early returns to theatre for graft hypoperfusion were reviewed. PROSPERO registration: (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020203873).

RESULTS

Literature searching identified 2069 articles for screening, with 131 reviewed and 12 selected for analysis comprising 5 individual case reports, one case series of 11 patients and 6 non-randomised controlled trials. Studies with similar methodologies were pooled because of the low number of studies and outcomes. Outcomes of interest were not reported for all patients. Intra-operative interventions comprising graft repositioning in 18 (16%) and vascular revision in 2 (2%) were performed in 115 patients undergoing intra-operative scans. There were no graft losses or returns to theatre for graft hypoperfusion (0 of 108 cases) compared to 7 of 71 (10%) without intraoperative scanning (P = 0.003). Three of 8 (38%) patients with high intra-operative resistive indices (RIs) were returned to theatre for hypoperfusion compared to 1 of 110 (1%) patients with normal resistive indices (P = <0.001). Ten of 13 (77%) patients with high RIs had delayed graft function compared to 10 of 40 (25%) with normal RIs (P = 0.001).

CONCLUSION

Despite the absence of randomised controlled trials, and heterogeneous small studies, adverse outcomes were reduced with intra-operative scanning. High intraoperative RIs were predictive of both delayed graft function and return to theatre for hypoperfusion.

Predictive factors of surgical complications in the first year following kidney transplantation

BACKGROUND

In the recent years, an increased use of marginal donors and grafts and a growing prevalence of peripheral arterial disease in the recipients have been observed. Meanwhile, the open surgical technique for kidney transplantation has not changed. The aim of this study is to analyze all surgical complications occurring in the first year after kidney transplant and to determine potential predictive risk factors.

METHOD

Data of the 399 patients who underwent kidney transplant in our University Hospital between January 2006 and December 2015 were retrospectively reviewed. The primary endpoint was the overall rate of vascular, parietal and urological complications at 1 year following kidney transplantation. The secondary outcomes were graft and patient' survival rates, and the identification of predictive factors of the surgical complications.

RESULTS

Twenty-four percent of patients developed 134 complications. Vascular complication represented 39% of all complications and resulted in 9 graft losses. Parietal and urological complications represented 46% and 15% of all complications, respectively, No parietal or urological complications were associated with graft loss. Five patients died during the first year, none of these cases was associated with graft loss. The graft survival rate reached 96% at 1 year, including patients still alive. The occurrence of surgical complication was associated with reduced graft survival at 1 year. Using a multivariate analysis, 4 predictive factors were identified: age, deceased donor, operative time and dyslipidemia.

CONCLUSION

Surgical complications after kidney transplantation remained frequent and age, deceased kidney donors, and operative time were identified as risk factors. As vascular complications were a major cause of early graft loss, efforts should aim to reduce their occurrence to increase graft survival.

Artificial Intelligence Pulse Coupled Neural Network Algorithm in the Diagnosis and Treatment of Severe Sepsis Complicated with Acute Kidney Injury under Ultrasound Image

The objective of this study was to explore the diagnosis of severe sepsis complicated with acute kidney injury (AKI) by ultrasonic image information based on the artificial intelligence pulse coupled neural network (PCNN) algorithm. In this study, an algorithm of ultrasonic image information enhancement based on the artificial intelligence PCNN was constructed and compared with the histogram equalization algorithm and linear transformation algorithm. After that, it was applied to the ultrasonic image diagnosis of 20 cases of severe sepsis combined with AKI in hospital. The condition of each patient was diagnosed by ultrasound image performance, change of renal resistance index (RRI), ultrasound score, and receiver operator characteristic curve (ROC) analysis. It was found that the histogram distribution of this algorithm was relatively uniform, and the information of each gray level was obviously retained and enhanced, which had the best effect in this algorithm; there was a marked individual difference in the values of RRI. Overall, the values of RRI showed a slight upward trend after admission to the intensive care unit (ICU). The RRI was taken as the dependent variable, time as the fixed-effect model, and patients as the random effect; the parameter value of time was between 0.012 and 0.015, p=0.000 < 0.05. Besides, there was no huge difference in the ultrasonic score among different time measurements (t = 1.348 and p=0.128 > 0.05). The area under the ROC curve of the RRI for the diagnosis of AKI at the 2^nd day, 4^th day, and 6^th day was 0.758, 0.841, and 0.856, respectively, which was all greater than 0.5 (p < 0.05). In conclusion, the proposed algorithm in this study could significantly enhance the amount of information in ultrasound images. In addition, the change of RRI values measured by ultrasound images based on the artificial intelligence PCNN was associated with AKI.

Predictive Value of Intraoperative Doppler Flowmetry for Delayed Graft Function in Kidney Transplantation: A Pilot Study

BACKGROUND

The delayed graft function (DGF) in kidney transplantation (KT) is a risk factor for long-term poor graft survival. The pathogenesis is multifactorial but mainly related to an ischemia-reperfusion injury. However, the graft hemodynamics have been recently identified as a key aspect for early DGF risk assessment and potential therapeutic intervention.

METHODS

A pilot study on 20 single kidney grafts from donor after brain death with intraoperative measurement of graft arterial flowmetry, 30 minutes after reperfusion. Exclusion criteria were grafts with multiple arteries or severe atherosclerosis of the recipient's external iliac artery.

RESULTS

KT recipients with DGF (n = 4, 20%) were homogenous with controls (n = 16) in terms of cold ischemia time, donor age, recipients' hemodynamic parameters, renal artery, and recipients' external iliac artery diameters. Nonetheless, at transplant, the kidney grafts that developed DGF were characterized by a significantly higher renal artery resistive index (DGF vs no-DGF 0.96 ± 0.04 vs 0.77 ± 0.13, P = .02), as well as lower flow extraction rate (24.8% ± 11.8 vs 59.2% ± 21.1, P < .01).

CONCLUSIONS

Intraoperative arterial graft flowmetry seems to be an effective tool to identify grafts at high risk of DGF.