Bariatric surgery for prospective living kidney donors with obesity?

The obesity epidemic has gripped the transplant community. With nearly 40% of adults in the United States being obese (BMI ≥30 kg/m² ) and 20% being morbidly obese (BMI ≥35 kg/m² ), the implications for both donors and recipients of solid organs continue to grow.¹ Nowhere is this more impactful than the candidacy of living kidney donors (LKDs). As increasing numbers of obese adults present for LKD consideration and evidence of inferior outcomes among obese LKDs grows, transplant surgeons will become progressively challenged by how to manage these patients in the clinic. Therefore, we offer this Personal Viewpoint to the transplant surgery community in order to review the current impact of obesity on living kidney donation, highlight what weight-loss interventions have already been attempted, and discuss the role that referral for weight-loss interventions including bariatric surgery might have going forward.

Trends in Bariatric Surgery Procedures among Patients with ESKD in the United States

BACKGROUND AND OBJECTIVES

Despite the potential for improving health status or increasing access to transplantation, national practice patterns for bariatric surgery in obese patients with ESKD are poorly understood. The purpose of this study was to describe current trends in surgical care for this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using 100% Medicare data, we identified all beneficiaries undergoing bariatric surgery in the United States between 2006 and 2016. We evaluated longitudinal practice patterns using linear regression models. We also estimated risk-adjusted complications, readmissions, and length of stay using Poisson regression for patients with and without ESKD.

RESULTS

The number of patients with ESKD undergoing bariatric surgery increased ninefold between 2006 and 2016. The proportional use of sleeve gastrectomy increased from <1% in 2006 to 84% in 2016. For sleeve gastrectomy, complication rates were similar between patients with and without ESKD (3.4% versus 3.6%, respectively; difference, -0.3%; 95% confidence interval, -1.3% to 0.1%; P=0.57). However, patients with ESKD had more readmissions (8.6% versus 5.4%, respectively; difference, 3.2%; 95% confidence interval, 1.9% to 4.6%; P<0.001) and slightly longer hospitals stays (2.2 versus 1.9 days, respectively; difference, 0.3; 95% confidence interval, 0.1 to 0.4; P<0.001).

CONCLUSIONS

This study suggests that laparoscopic sleeve gastrectomy has replaced Roux-en-Y gastric bypass as the most common bariatric surgical procedure in patients with ESKD. The data also demonstrate a favorable complication profile in patients with sleeve gastrectomy.

The impact of intraoperative fluid management during laparoscopic donor nephrectomy on donor and recipient outcomes

BACKGROUND

Intraoperative fluid management during laparoscopic donor nephrectomy (LDN) may have a significant effect on donor and recipient outcomes. We sought to quantify variability in fluid management and investigate its impact on donor and recipient outcomes.

METHODS

A retrospective review of patients who underwent LDN from July 2011 to January 2016 with paired kidney recipients at a single center was performed. Patients were divided into tertiles of intraoperative fluid management (standard, high, and aggressive). Donor and recipient demographics, intraoperative data, and postoperative outcomes were analyzed.

RESULTS

Overall, 413 paired kidney donors and recipients were identified. Intraoperative fluid management (mL/h) was highly variable with no correlation to donor weight (kg) (R = 0.017). The aggressive fluid management group had significantly lower recipient creatinine levels on postoperative day 1. However, no significant differences were noted in creatinine levels out to 6 months between groups. No significant differences were noted in recipient postoperative complications, graft loss, and death. There was a significant increase (P < 0.01) in the number of total donor complications in the aggressive fluid management group.

CONCLUSIONS

Aggressive fluid management during LDN does not improve recipient outcomes and may worsen donor outcomes compared to standard fluid management.

A Video-Based Coaching Intervention to Improve Surgical Skill in Fourth-Year Medical Students

OBJECTIVE

For senior medical students pursuing careers in surgery, specific technical feedback is critical for developing foundational skills in preparation for residency. This pilot study seeks to assess the feasibility of a video-based coaching intervention to improve the suturing skills of fourth-year medical students.

DESIGN

Fourth-year medical students pursuing careers in surgery were randomized to intervention vs. control groups and completed 2 video recorded suture tasks. Students in the intervention group received a structured coaching session between consecutive suturing tasks, whereas students in the control group did not. Each coaching session consisted of a video review of the students' first suture task with a faculty member that provided directed feedback regarding technique. Following each suturing task, students were asked to self-assess their performance and provide feedback regarding the utility of the coaching session. All videos were deidentified and graded by independent faculty members for evaluation of suture technique.

SETTING

The University of Michigan Medical School in Ann Arbor, Michigan.

PARTICIPANTS

All fourth-year medical students pursuing careers in surgical specialties were contacted via e-mail for voluntary participation. In all, 16 students completed both baseline and follow up suture tasks.

RESULTS

All students who completed the coaching session would definitely recommend the session for other students. A total of 94% of the students strongly agreed that the exercise was a beneficial experience, and 75% strongly agreed that it improved their technical skills. Based on faculty grading, students in the intervention group demonstrated greater average improvements in bimanual dexterity compared to students in the control group; whereas students in the control group demonstrated greater average improvements in domains of efficiency and tissue handling compared to the intervention group. Based on student self-assessments, those in the intervention group had greater subjective improvements in all scored domains of bimanual dexterity, efficiency, tissue handling, and consistency compared to the control group. Subjective, free-response comments centered on themes of becoming more aware of hand movements when viewing their suturing from a new perspective, and the usefulness of the coaching advice.

CONCLUSIONS

This pilot study demonstrates the feasibility of a video-based coaching intervention for senior medical students. Students who participated in the coaching arm of the intervention noticed improvements in all domains of technical skill and noted that the experience was overwhelmingly positive. In summary, video-based review shows promise as an educational tool in medical education as a means to provide specific technical feedback.

Abdominal adiposity, body composition and survival after liver transplantation

BACKGROUND

Current measures of obesity do not accurately describe body composition. Using cross-sectional imaging, objective measures of musculature and adiposity are possible and may inform efforts to optimize liver transplantation outcomes.

METHODS

Abdominal visceral fat area and psoas muscle cross-sectional area were measured on CT scans for 348 liver transplant recipients. After controlling for donor and recipient characteristics, survival analysis was performed using Cox regression.

RESULTS

Visceral fat area was significantly associated with post-transplant mortality (p < 0.001; HR = 1.06 per 10 cm(2) , 95% CI: 1.04-1.09), as were positive hepatitis C status (p = 0.004; HR = 1.78, 95% CI: 1.21-2.61) and total psoas area (TPA) (p < 0.001; HR = 0.91 per cm(2) , 95% CI: 0.88-0.94). Among patients with smaller TPA, the patients with high visceral fat area had 71.8% one-yr survival compared to 81.8% for those with low visceral fat area (p = 0.15). At five yr, the smaller muscle patients with high visceral fat area had 36.9% survival compared to 58.2% for those with low visceral fat area (p = 0.023).

CONCLUSIONS

Abdominal adiposity is associated with survival after liver transplantation, especially in patients with small trunk muscle size. When coupled with trunk musculature, abdominal adiposity offers direct characterization of body composition that can aid preoperative risk evaluation and inform transplant decision-making.

Evaluating the Use of Twitter to Enhance the Educational Experience of a Medical School Surgery Clerkship

OBJECTIVE

Although it has been suggested that social-networking services such as Twitter could be used as a tool for medical education, few studies have evaluated its use in this setting. We sought to evaluate the use of Twitter as a novel educational tool in a medical school surgery clerkship. We hypothesized that Twitter can enhance the educational experience of clerkship students.

DESIGN

We performed a prospective observational study. We created a new Twitter account, and delivered approximately 3 tweets per day consisting of succinct, objective surgical facts. Students were administered pre- and postclerkship surveys, and aggregate test scores were obtained for participating students and historical controls.

SETTING

Required third-year medical school surgery clerkship at the University of Michigan large tertiary-care academic hospital.

PARTICIPANTS

Third-year medical students.

RESULTS

The survey response rate was 94%. Preclerkship surveys revealed that most (87%) students have smartphones, and are familiar with Twitter (80% have used before). Following completion of the clerkship, most students (73%) reported using the Twitter tool, and 20% used it frequently. Overall, 59% believed it positively influenced their educational experience and very few believed it had a negative influence (2%). However, many (53%) did not believe it influenced their clerkship engagement. Aggregate mean National Board of Medical Examiners Shelf Examination scores were not significantly different in an analysis of medical student classes completing the clerkship before or after the Twitter tool (p = 0.37).

CONCLUSIONS

Most of today's learners are familiar with social media, and own the technology necessary to implement novel educational tools in this platform. Applications such as Twitter can be facile educational tools to supplement and enhance the experience of students on a medical school clerkship.

Geographic variation in use of laparoscopic colectomy for colon cancer

PURPOSE

Emerging evidence supporting the use of laparoscopic colectomy in patients with cancer has led to dramatic increases in utilization. Though certain patient and hospital characteristics may be associated with the use of laparoscopy, the influence of geography is poorly understood.

METHODS

We used national Medicare claims data from 2009 and 2010 to examine geographic variation in utilization of laparoscopic colectomy for patients with colon cancer. Patients were assigned to hospital referral regions (HRRs) where they were treated. Multivariable logistic regression was used to generate age, sex, and race-adjusted rates of laparoscopic colectomy for each HRR. Patient quintiles of adjusted HRR utilization were used to evaluate differences in patient and hospital characteristics across low and high-utilizing HRRs.

RESULTS

A total of 93,786 patients underwent colon resections at 3,476 hospitals during the study period, of which 30,502 (32.5%) were performed laparoscopically. Differences in patient characteristics between the lowest and highest quintiles of HRR utilization were negligible, and there was no difference in the availability of laparoscopic technology. Yet adjusted rates of laparoscopic colectomy utilization varied from 0% to 66.8% across 306 HRRs in the United States.

CONCLUSION

There is wide geographic variation in the utilization of laparoscopic colectomy for Medicare patients with colon cancer, suggesting treatment location may substantially influence a patient's options for surgical approach. Future efforts to reduce variation will require increased dissemination of training techniques, novel opportunities for learning among surgeons, and enhanced educational resources for patients.

Morphometric age and mortality after liver transplant

IMPORTANCE

Morphometric assessment has emerged as a strong predictor of postoperative morbidity and mortality. However, a gap exists in translating this knowledge to bedside decision making. We introduced a novel measure of patient-centered surgical risk assessment: morphometric age.

OBJECTIVE

To investigate the relationship between morphometric age and posttransplant survival.

DATA SOURCES

Medical records of recipients of deceased-donor liver transplants (study population) and kidney donors/trauma patients (morphometric age control population).

STUDY SELECTION

A retrospective cohort study of 348 liver transplant patients and 3313 control patients. We assessed medical records for validated morphometric characteristics of aging (psoas area, psoas density, and abdominal aortic calcification). We created a model (stratified by sex) for a morphometric age equation, which we then calculated for the control population using multivariate linear regression modeling (covariates). These models were then applied to the study population to determine each patient's morphometric age.

DATA EXTRACTION AND SYNTHESIS

All analytic steps related to measuring morphometric characteristics were obtained via custom algorithms programmed into commercially available software. An independent observer confirmed all algorithm outputs. Trained assistants performed medical record review to obtain patient characteristics.

RESULTS

Cox proportional hazards regression model showed that morphometric age was a significant independent predictor of overall mortality (hazard ratio, 1.03 per morphometric year [95% CI, 1.02-1.04; P < .001]) after liver transplant. Chronologic age was not a significant covariate for survival (hazard ratio, 1.02 per year [95% CI, 0.99-1.04; P = .21]). Morphometric age stratified patients at high and low risk for mortality. For example, patients in the middle chronologic age tertile who jumped to the oldest morphometric tertile have worse outcomes than those who jumped to the youngest morphometric tertile (74.4% vs 93.2% survival at 1 year [P = .03]; 45.2% vs 75.0% at 5 years [P = .03]).

CONCLUSIONS AND RELEVANCE

Morphometric age correlated with mortality after liver transplant with better discrimination than chronologic age. Assigning a morphometric age to potential liver transplant recipients could improve prediction of postoperative mortality risk.

Cigarette smoking in living kidney donors: donor and recipient outcomes

BACKGROUND

Living kidney donor pools are expanding with the use of "medically complex" donors. Whether or not to include cigarette smokers as living kidney donors remains unclear. The aim of this study was to determine the relationship between donor smoking and recipient outcomes. We hypothesized that donor smoking would increase donor complications and decrease allograft and recipient survival over time.

METHODS

The charts of 602 living kidney donors and their recipients were retrospectively reviewed. Kaplan-Meier survival analysis and Cox modeling were used to assess the relationships between smoking and recipient and allograft survival.

RESULTS

No difference in postoperative complications was seen in smoking versus non-smoking donors. Donor smoking at time of evaluation did not significantly decrease allograft survival (HR = 1.19, p = 0.52), but recipient smoking at evaluation did reduce allograft survival (HR = 1.74, p = 0.05). Both donor and recipient smoking decreased recipient survival (HR = 1.93, p < 0.01 vs HR = 1.74, p = 0.048).

DISCUSSION

When controlled for donor and recipient factors, cigarette smoking by living kidney donors significantly reduced recipient survival. This datum suggests that careful attention to smoking history is an important clinical measure in which to counsel potential donors and recipients. Policy efforts to limit donors with a recent smoking history should be balanced with the overall shortage of appropriate kidney donors.