Impact of Surgeon's Experience on Vascular and Haemorrhagic Complications After Kidney Transplantation

Surgical Complications Following Renal Transplantation in a Large Institutional Cohort

Background

Successful renal transplantation (RTx) relies on immunosuppression and an optimal surgical course with few surgical complications. Studies reporting the postoperative complications after RTx are heterogeneous and often lack systematic reporting of complications. This study aims to describe and identify postoperative short-term and long-term complications after RTx in a large institutional cohort and identify risk factors for a complicated surgical course.

Methods

The study is a retrospective single-center cohort of 571 recipients who underwent living or deceased donor open RTx between 2014 and 2021. Data were collected on background information and perioperative and postoperative data. Complications were defined as short-term (<30 d) or long-term (>30 d) after transplantation and graded according to the Clavien-Dindo classification. Multivariable logistic regression was performed to evaluate risk factors for serious short-term complications and multivariable time-dependent Cox regression to evaluate risk factors for long-term complications.

Results

A total of 351 patients received a graft from a deceased donor, and 144 of these grafts were on perfusion machine before transplantation. One or more short-term complications occurred in 345 (60%) patients. Previous RTx was associated with short-term Clavien-Dindo >2 complications in recipients (odds ratio = 2.08; 95% confidence interval [CI], 1.18-3.69; P = 0.01). Being underweight (body mass index <18.5) in combination with increasing age increased the odds of short-term Clavien-Dindo >2 and vascular complications. Increasing blood loss per 100 mL was associated with increased odds of short-term Clavien-Dindo >2 (odds ratio = 1.11; 95% CI, 1.01-1.21; P = 0.032). No associations were found for long-term complications after RTx. The 5-y cumulative incidence of graft loss was 12.6% (95% CI, 8.9-16.3).

Conclusions

Short-term complications are common after RTx, and risk factors for severe short-term complications include previous RTx, increasing age, and low body mass index. No risk factors were identified for severe long-term complications. Further studies should explore whether new surgical techniques can reduce surgical complications in RTx.

Scoping review: The terminology used to describe major abdominal surgical procedures

BACKGROUND

Major abdominal surgery (MAS) can have a profound impact on the patient but there is currently no consensus as to which surgical procedures constitute MAS. The main objective of this work is to ascertain the terminology used to describe MAS procedures and to apply these findings in order to propose a definition of MAS.

METHODS

The following databases were searched: Ovid MEDLINE (R) ALL, Embase Classic and Embase (via OvidSP), Global Health (via OvidSP), Health Management Information Consortium (via OvidSP), APA PsycInfo (via OvidSP), PubMed and Web of Science. Original research articles, published between 1980 and April 26, 2022 that contained a description of MAS procedure were included in this study. Article screening and data extraction was undertaken independently by 3 authors. Content analysis was performed to identify key terminology used to describe MAS.

RESULTS

Five thousand six hundred and sixty three articles were identified, of which 767 underwent full-text review and 312 were included in the scoping review. Content analysis resulted in 4 main categories: (1) pre-operative factors, (2) intraoperative factors, (3) operation-related factors, (4) post-operative factors. Operation-related factors was the predominant category (1137 references coded). The gastrointestinal resection made the vast majority of the references coded (591).

CONCLUSIONS

Based on these results, the term "major abdominal surgery" should be defined as an intra-peritoneal operation with no primary involvement of the thorax, involving either luminal resection and/or resection of a solid organ associated with the gastrointestinal tract. However, further work is required to verify this definition using real world data.

Assessing textbook outcomes following major liver surgery in association with obesity at a referral academic center

INTRODUCTION

Outcomes of major surgeries in tertiary educational hospitals have been complicated by the referral of high-risk patients and the participation of trainees in surgical procedures. We analyzed outcomes of major hepatectomies in a tertiary academic setting emphasizing the role of training and obesity on textbook outcomes (TO).

MATERIALS AND METHODS

971 adult patients who underwent open major hepatectomy (Mesohepatectomy [n = 111], hemihepatectomy [n = 610], and extended hepatectomy [n = 250]) were evaluated. A TO was defined as: a negative resection margin, no grade B/C bile leak, no major complications, no in-hospital mortality, and no 30-day readmission. TOs were compared following operations performed by senior surgeons and those performed by junior surgeons under the supervision of senior surgeons and between patients with and without obesity.

RESULTS

TO was achieved in 70.1% of patients overall (78.4% in mesohepatectomy, 73.1% in hemihepatectomy, and 59.2% in extended hepatectomy). The rate of TO was similar following operations performed by and supervised by a senior surgeon (69.3% vs 71.0%, p = 0.570). The rate of TO was significantly lower in patients with obesity (41.5% vs 74.6%, p < 0.001). Factors including increased age (odds ratio [OR] for 10-year increase = 0.83, 95% confidence interval [CI]: 0.73-0.96, p = 0.009), obesity (OR = 0.25, 95%CI: 0.16-0.37, p < 0.001), biliodigestive anastomosis (OR = 0.27, 95%CI: 0.19-0.40, p < 0.001), and portal vein resection (OR = 0.49, 95%CI: 0.28-0.87, p = 0.014) lower the rate of TO.

CONCLUSION

Promising outcomes are possible after major hepatectomy in an academic setting. Obese patients and those undergoing more complex surgeries had a higher risk of poor postoperative outcomes.

Robot-assisted versus laparoscopic living donor nephrectomy: superior outcomes after completion of the learning curve

The use of robots in donor nephrectomy has increased in recent years. However, whether robot-assisted methods have better outcomes than traditional laparoscopic methods and how surgical experience influences these outcomes remains unclear. This meta-analysis compares the outcomes of robot-assisted donor nephrectomy (RADN) with those of laparoscopic donor nephrectomy (LDN) and to investigate the effects of surgical experience on these outcomes. A systematic literature search was conducted in Medline (through PubMed) and Web of Science databases. Perioperative data were extracted for meta-analysis. To assess the impact of the learning curve, a subgroup analysis was performed to compare outcomes between inexperienced and experienced surgeons. Seventeen studies with 6970 donors were included. Blood loss was lower (mean difference [MD] = - 13.28, p < 0.01) and the warm ischemia time was shorter (MD = - 0.13, p < 0.05) in the LDN group than the RADN group. There were no significant differences in terms of conversion to open surgery, operation time, surgical complications, hospital stay, costs, and delayed graft function between the groups. Subgroup analysis revealed that operation time (MD = - 1.09, p < 0.01) and length of hospital stay (MD = - 1.54, p < 0.05) were shorter and the rate of conversion to open surgery (odds ratios [OR] = 0.14, p < 0.0001) and overall surgical complications (OR = 0.23, p < 0.05) were lower in experienced RADN surgeons than in experienced LDN surgeons. Surgical experience enhances the perioperative outcomes following RADN more than it does following LDN. This suggests that RADN could be the method of choice for living donor nephrectomy as soon as surgeons gain sufficient experience in robotic surgery.

Diagnostic and therapeutic strategies for vascular complications after renal transplantation: a single-center experience in 2,304 renal transplantations

Vascular complications after renal transplantation are one of the serious surgical complications, which can affect the transplantation outcome and even endanger life if not treated properly. We performed a retrospective analysis of the 2,304 renal transplantations procedures completed between the period of Jan., 2015 and Jan., 2022, which consisted of 1,658 male patients and 646 female patients. Among the above cases, there were 54 cases of vascular complications after renal transplantation, the incidence of vascular complications in our study was 2.34% (54/2,304), the most common vascular complication was transplanted renal artery stenosis (TRAS, n = 36), followed by external iliac artery dissection (n = 5), renal artery rupture (n = 4), renal vein thrombosis (n = 3), renal artery thrombosis (n = 2), renal artery dissection (n = 1), renal artery pseudoaneurysm (n = 1), and internal iliac artery pseudoaneurysm (n = 1), and renal artery kinking (n = 1). 40 patients were treated by percutaneous transluminal angioplasty (PTA), including 3 balloon catheter dilatation and 37 endovascular stentings, and 14 underwent open surgery. Eventually, 9 patients had graft nephrectomy, resulting in an overall treatment rate of 81.5%. Most vascular complications can be treated satisfactorily with PTA. However, the overall treatment of renal artery rupture, thrombosis, renal artery kinking, and other complications is poor, and the rate of transplanted renal loss is high.

The learning curve for open and minimally-invasive kidney transplantation: a systematic review

INTRODUCTION

There is lack of evidence on the impact of surgeons' learning curve on postoperative outcomes after open (OKT) or minimally-invasive (robot-assisted) kidney transplantation (RAKT). The aim of the review was to assess the learning curve (LC) for OKT and RAKT, focusing on intra-, perioperative and functional outcomes.

EVIDENCE ACQUISITION

A systematic review of the English-language literature published between 01/01/2000 - 10/12/2021 was conducted using the MEDLINE (Via PubMed), Web of Science and the Cochrane Library databases according to the principles highlighted by the EAU Guidelines Office and the PRISMA statement recommendations. The review protocol was registered on PROSPERO (CRD42022301132). The overall quality of evidence was assessed according to GRADE recommendations.

EVIDENCE SYNTHESIS

Twelve studies were included in the qualitative analysis. Surgical competence in terms of operative and re-warming times was defined after 30 cases in OKT and after 11-35 cases in RAKT. Decreased complications rates were observed after 20-33 cases in OKT and 10-30 cases in RAKT. Optimal functional outcomes were achieved after 33 cases in OKT and 15-25 cases in RAKT. However, while a poor OKT experience did not influence the LC for RAKT, lack of robotic surgery exposure could lead to a longer LC for the robotic approach.

CONCLUSIONS

OKT and RAKT appear to have similar LCs and might require about 30 cases to achieve optimal surgical and functional outcomes. Previous expertise in OKT is warranted to shorten the LC for RAKT. Further research is needed to validate these thresholds using standardized reporting metrics.

Risk Factors of Rejection in Renal Transplant Recipients: A Narrative Review

Multiple factors influence graft rejection after kidney transplantation. Pre-operative factors affecting graft function and survival include donor and recipient characteristics such as age, gender, race, and immunologic compatibility. In addition, several peri- and post-operative parameters affect graft function and rejection, such as cold and warm ischemia times, and post-operative immunosuppressive treatment. Exposure to non-self-human leucocyte antigens (HLAs) prior to transplantation up-regulates the recipient’s immune system. A higher rate of acute rejection is observed in transplant recipients with a history of pregnancies or significant exposure to blood products because these patients have higher panel reactive antibody (PRA) levels. Identifying these risk factors will help physicians to reduce the risk of allograft rejection, thereby promoting graft survival. In the current review, we summarize the existing literature on donor- and recipient-related risk factors of graft rejection and graft loss following kidney transplantation.

Pre-transplant donor-specific HLA antibodies and risk for poor first-year renal transplant outcomes: results from the Swiss Transplant Cohort Study

The aim of this study was to analyze first year renal outcomes in a nationwide prospective multicenter cohort comprising 2215 renal transplants, with a special emphasis on the presence of pre-transplant donor-specific HLA antibodies (DSA). All transplants had a complete virtual crossmatch and DSA were detected in 19% (411/2215). The investigated composite endpoint was a poor first-year outcome defined as (i) allograft failure or (ii) death or (iii) poor allograft function (eGFR ≤25 ml/min/1.73 m² ) at one year. Two hundred and twenty-one (221/2215; 10%) transplants showed a poor first-year outcome. Rejection (24/70; 34%) was the most common reason for graft failure. First-year patient's death was rare (48/2215; 2%). There were no statistically significant differences between DSA-positive and DSA-negative transplants regarding composite and each individual endpoint, as well as reasons for graft failure and death. DSA-positive transplants experienced more frequently rejection episodes, mainly antibody-mediated rejection (both P < 0.0001). The combination of DSA and any first year rejection was associated with the overall poorest death-censored allograft survival (P < 0.0001). In conclusion, presence of pre-transplant DSA per se does not affect first year outcomes. However, DSA-positive transplants experiencing first year rejection are a high-risk population for poor allograft survival and may benefit from intense clinical surveillance.

Extraperitoneal kidney transplantation: a comparison between children weighting ≤15 kg and >15 kg. Experience of a single institution

Extraperitoneal approach is sometimes recommended for kidney transplantation (KT) in children weighting <15 kg. We hypothesized that this approach might be as successful as in patients with normal weight. Data of all consecutive KTs performed between 2013 and 2019 were retrospectively reviewed. Early outcomes and surgical complications were compared between children weighing ≤15 kg (low‐weight (LW) group) and those weighing >15 kg (Normal‐weight (NW) group). All the 108 KTs were performed through an extraperitoneal approach. The LW group included 31 patients (mean age 3.5 ± 1.4 years), whose mean weight was 11.1 ± 2.0 kg. In the LW group,—a primary graft nonfunction (PNGF) occurred in one patient (3.2%), surgical complications occurred in nine (29%), with four venous thrombosis. In the NW group, PNGF occurred in one case (1.3%), delayed graft function (DGF) in eight (10%), surgical complications in 11 (14%) with only one case of venous thrombosis. In both groups, no need for patch during wound closure and no wound dehiscence were reported. The extraperitoneal approach can be effectively used in LW children. No differences were observed in the overall complication rate (P = 0.10), except for the occurrence of venous thrombosis (P = 0.02). This might be related to patients’ characteristics of the LW group.

Prophylactic antithrombotic management in adult and pediatric kidney transplantation: A systematic review and meta-analysis

BACKGROUND

RGT is a major cause for early graft loss after KTx. Although evidence-based recommendations are lacking, aP is often used to prevent RGT. This systematic review aimed to determine the effectiveness and safety of aP in adult and pediatric KTx recipients.

METHODS

MEDLINE, EMBASE, Cochrane Controlled Trials Register, conference proceedings, and electronic databases for trial registries were searched for eligible studies using search terms relevant to this review (April 21, 2020). The systematic review was carried out following the recommendations of the Cochrane Collaboration and the Prefered Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement.

RESULTS

Twelve studies comprising 2370 patients (adult = 1415, pediatric = 955) were included, of which three were RCTs. The overall risk for developing RGT was lower in the group with aP compared with the control group (RR 0.24, 95% confidence interval 0.12-0.49). The antithrombotic drugs used were heparin (7/12), acetylsalicylic acid (2/12), a combination of both (2/12), and dipyridamole (1/12) with a high variability in timing, dosing, and mode of application. Adverse effects were reported rarely, with minor bleeding as the main complication. The non-randomized studies had significant risks of bias in the domains of patient selection, confounder, and measurement of outcomes.

CONCLUSION

Based on pooled analysis, aP seems to reduce the risk of RGT in KTx. However, the reliability of these results is limited, as the quality of the available studies is poor and information on adverse effects associated with aP is scarce. Additional high-quality research is urgently needed to provide sufficient data supporting the use of aP in KTx.

Intraoperative Aneurysm Rupture: Surgical Experience and the Rate of Intraoperative Rupture in a Series of 1000 Aneurysms Operated on by a Single Neurosurgeon

OBJECTIVE

This study aims to examine the risk factors that can cause intraoperative rupture (IOR), and especially, the role of surgical experience. To our knowledge, this is the first study to analyze the effect of the surgeon's experience on the IOR rate in 2 different perspectives.

METHODS

A total of 1000 aneurysms in 775 patients were operated on by a single neurosurgeon. The clinical and radiologic data and intraoperative video recordings of all patients were retrospectively analyzed. To evaluate the role of the surgeon's experience on the IOR rate, the aneurysms were divided chronologically into both 5-year periods and each 100 aneurysms. Number, stage, severity, location, management of IORs, and patients' outcomes were determined.

RESULTS

IOR occurred in 55 aneurysms (5.5% per aneurysm). The incidence of IOR decreased gradually in the first 2 groups of 5-year periods (11.4% and 5.9%, respectively). However, in the last 3 groups, the decline remained stable (4%-5%). Considering all groups, this decrease was statistically significant (P = 0.037). When this evaluation was made for each group of 100 aneurysms, similar results were obtained. Mortality also gradually decreased over the years (P = 0.035). Of 8 possible risk factors, rupture status was found to be the only independent predictor for IOR (OR, 8.68; 95% confidence interval, 3.69-20.47; P <0.001).

CONCLUSIONS

Increased surgical experience reduces the IOR rate from 10%-11% to 4%-5% after an average of 250 aneurysm operations. However, this rate does not decrease further with more experience. To our knowledge, a learning curve regarding IOR is presented for the first time in the literature.

Current practice of antithrombotic prophylaxis in pediatric kidney transplantation-Results of an international survey on behalf of the European Society for Paediatric Nephrology

BACKGROUND

Renal graft thrombosis (RGT) is one of the main causes for early graft loss in pediatric kidney transplantation (KTx). Despite the lack of evidence-based recommendations, antithrombotic prophylaxis (aP) is used to prevent RGT.

METHODS

An online survey supported by the European Society for Pediatric Nephrology was developed to investigate the current practice of aP in pediatric KTx recipients <18 years.

RESULTS

A total of 80 pediatric KTx centers from 37 countries participated in the survey. Antithrombotic prophylaxis was performed in 96% of the pediatric renal transplant centers (all/selected patients: 54%/42%). The main overall used drugs were as follows: low-molecular-weight heparin (89%), unfractionated heparin (UFH) (69%), and acetylsalicylic acid (ASS) (55%). Ten different aP management strategies were identified as follows: 51% used a single drug and 48% combined two drugs sequentially. The corresponding centers started aP predominantly within 24 hours after pediatric KTx; 51% preferred UFH for starting aP. In centers switching to a second drug (51%), this change was performed after 10 ± 6 days; of these 57% preferred ASS for maintenance aP. Reported median aP duration was 51 days (range 1-360).

CONCLUSIONS

Despite the use of aP in almost all responding pediatric KTx centers, there is no uniform management strategy. Notwithstanding, UFH seems to be the preferred drug for the early post-operative period of pediatric KTx, and ASS for maintenance prophylaxis following pediatric KTx. Prospective studies are needed to further evaluate the benefits and risks of aP, preferably resulting in guidelines for the management in pediatric KTx.

Aorto-Iliac Artery Calcification Prior to Kidney Transplantation

As vascular calcification is common in kidney transplant candidates, aorto-iliac vessel imaging is performed for surgical planning. The aim of the present study was to investigate whether a novel non-contrast enhanced computed tomography-based quantification technique for aorto-iliac calcification can be used for cardiovascular risk stratification prior to kidney transplantation. In this dual-center cohort study, we measured the aorto-iliac calcium score (CaScore) of 547 patients within three years prior to transplantation (2005-2018). During a median (interquartile range) follow-up of 3.1 (1.4, 5.2) years after transplantation, 80 (14.7%) patients died, of which 32 (40.0%) died due to cardiovascular causes, and 84 (15.5%) patients had a cardiovascular event. Kaplan-Meier survival curves showed significant differences between the CaScore tertiles for cumulative overall-survival (Log-rank test p < 0.0001), cardiovascular survival (p < 0.0001), and cardiovascular event-free survival (p < 0.001). In multivariable Cox regression, the aorto-iliac CaScore was associated with all-cause mortality (hazard ratio 1.53, 95%CI 1.14-2.06, p = 0.005), cardiovascular mortality (2.04, 1.20-3.45, p = 0.008), and cardiovascular events (1.35, 1.01-1.80, p = 0.042). These independent associations of the aorto-iliac CaScore with the outcome measures can improve the identification of patients at risk for (cardiovascular) death and those who could potentially benefit from stringent cardiovascular monitoring to improve their prognosis after transplantation.

Surgical learning curve in kidney transplantation: A systematic review and meta-analysis

AIM

To assess the impact of the learning curve of kidney transplantation on operative and postoperative complications.

METHODS

A literature search was systematically conducted to evaluate the significance of the learning curve on complications in kidney transplantation. Meta-analyses of the effect of the learning curve on warm ischemic time, total operating time (TOT), vascular and urological complications, postoperative bleeding, lymphocele and infection.

RESULTS

Nine studies met the inclusion criteria and 2762 patients were included in the present meta-analyses. Surgeons at the beginning of the learning curve were found to have longer TOT (mean difference 41.77 (95% CI: 4.48-79.06; P = .03) and more urological complications (risk ratio 3.93; 95% CI: 1.87-8.25; P < .01). No differences were seen in warm ischemic time, postoperative bleeding, lymphocele, and vascular complications.

CONCLUSION

Surgeons at the beginning of their learning curve have a longer TOT and more urological complications, without an effect on postoperative bleeding, lymphocele, infection and vascular complications. For interpretation of the outcomes, the quality and sample size of the evidence should be taken into consideration.

The weekend effect in kidney transplantation outcomes: a French cohort-based study

Numerous studies have reported a weekend effect on outcomes for diseases treated at hospitals. No study has been conducted in France for kidney transplantation. We therefore performed a cohort-based study to evaluate whether outcomes of kidney transplant recipients display a weekend effect. Data were extracted from the French DIVAT cohort. Patients aged 18 years and older, transplanted with a single kidney from deceased donors between 2005 and 2017 were studied. Linear regression, logistic regression, and cause-specific Cox model were used. Among the 6652 studied patients, 4653 patients were transplanted during weekdays (69.9%) versus 1999 during weekends (30.1%). The only statistically significant difference was the percentage of patients with vascular surgical complication(s) at 30 days: 13.3% in the weekend group versus 16.2% in the weekday group 0.79 (95% CI: 0.68; 0.92). We did not observe other significant differences for the other outcomes: patient or graft survival, the risk of acute rejection episodes, the 30-day percentage of urological complications, and the 1-year estimated glomerular filtration rate. Our study highlights a small protective weekend effect with less post-surgery vascular complications compared to weekdays. This paradox might be explained by a different handling of weekend transplantations.

Surgical outcomes after pediatric kidney transplantation at the University of Heidelberg

BACKGROUND

Kidney transplantation (KTx) is the treatment of choice for children with end-stage renal disease (ESRD).

OBJECTIVE

An update of 48 years of surgical experience with pediatric KTx (PKTx) is presented, and the results between recipients of organs from deceased donors (DDs) and living donors (LDs) are compared.

STUDY DESIGN

All patients younger than 18 years who underwent KTx between 1967 and 2015 were evaluated. Data from 540 PKTx operations (409 DD and 131 LD) were obtained from the transplant center database. Peri-operative data and graft and patient survival were analyzed in the DD and LD groups.

RESULTS

Fewer recipients in the LD group underwent dialysis before PKTx than those in the DD group (50.8% in LD vs. 94.9% in DD, P < 0.001). The mean duration of dialysis (DD: 798 ± 525 days vs. LD: 625 ± 650 days, P = 0.03), time on the waiting list (DD: 472 ± 435 days vs. LD: 120 ± 243 days, P < 0.001), cold ischemia time (CIT) (DD: 1206 ± 368 min vs. LD: 140 ± 63 min, P < 0.001), operation time, and hospital stay were lower in the LD group. Except for arterial stenosis, the rates of postoperative vascular and urological complications were not different between the two groups. The cumulative 25-year graft and patient survival rates were 46.4% and 84.1% in the DD group and 76.5% and 96.1% in the LD group, respectively.

DISCUSSION

PKTx is the treatment of choice for children with ESRD. Graft quality has a direct impact on KTx outcome and rate of graft failure. Better HLA compatibility and shorter CIT reduce the impairment of graft function after LD PKTx. In addition, Establishment of an interdisciplinary approach using an individualized risk assessment and prevention model can improve PKTx outcomes.

CONCLUSION

Compared with DD PKTx, LD PKTx has better graft survival associated with a shorter duration of preceding dialysis, waiting time, and CIT and seems to be more beneficial for children.