Does donor nephron mass have any impact on graft survival?

OBJECTIVES: Functioning nephron mass namely, the number of nephrons in the grafted kidney, is one of the nonimmunologic factors that may have some impact on long-term graft survival. The aim of this study was to assess the impact of donor nephron mass on graft outcome in the recipient. MATERIALS AND METHODS: From 1989 to 2005, 1000 renal transplants were performed at our center. The 217 studied cases were followed for an average of 8 years. All patients received grafts from living donors. The weight of the grafted kidney (donor nephron mass) as well as the recipient's body mass index (BMI) were measured at the time of operation. Nephron mass index (NMI) was defined as the ratio of donor nephron mass to recipient BMI. Associations between variables were tested by logistic regression and Pearson correlation using the SAS system and S-plus statistical software. To evaluate graft function, we determined serum creatinine values, acute rejection episodes and chronic nephropathy. RESULTS: Mean NMI was 8.07 +/- 0.2 and mean creatinine level was 1.43 +/- 0.4 mg/dL. There were 32 cases (14.7%) of acute rejection, who were managed successfully with antithymocyte globulin (ATG) in 28 cases. Four patients lost their grafts. There were 15 cases (7%) of graft loss due to chronic rejection. Using Pearson correlation, we observed no association between NMI and mean serum creatinine level. Logistic regression showed a significant relation between NMI and acute rejection (P<.05) with an odds ratio of 2.0. There was no significant correlation between NMI and chronic rejection. CONCLUSIONS: The lower the NMI, the greater the short-term graft loss. However, in the long term, no significant correlation was found between graft survival and NMI. Also, mean creatinine level was not significantly different among patients regardless of NMI.     

Does delayed graft function in the first kidney transplant influence graft outcome in a subsequent transplant?

Background

In kidney transplantation, delayed graft function (DGF) portends adverse graft and patient outcomes. It is unclear whether DGF in the first kidney transplant would adversely impact the outcome of a subsequent transplant.

Methods

Utilizing data from the Organ Procurement and Transplant Network, we identified patients ≥ 18 years of age who underwent at least two deceased donor kidney transplantation (DDKT) between 1987 and 2010. Patients were then divided into two groups based on whether or not they developed DGF in the first transplant (1st TXP DGF group and 1st TXP no-DGF group). Unadjusted and adjusted graft survivals (Cox regression) between the groups were compared.

Results

A total of 10,628 patients were identified who received more than one DDKT (3672 patients in the 1st TXP DGF group and 6956 patients in the 1st TXP no-DGF group). A higher incidence of DGF was observed with the second transplant in patients who had DGF in the first transplant (34% vs 26%, P = .001). Unadjusted graft survival for the second transplant was superior in the 1st TXP no-DGF group (P = .002). After correction for confounding variables, DGF in the first transplant did not have significant adverse impact on the graft survival of the second transplant (hazard ratio 1.2 with 95% confidence interval 0.96–1.09, P = .44).

Conclusions

In patients undergoing more than one DDKT, DGF in the first transplant is associated with higher incidence of DGF in the subsequent transplant but did not have independent adverse influence on the outcome of that graft.     

Does resident hours reduction have an impact on surgical outcomes?

BACKGROUND: We assessed the impact of restricting surgical resident work hours as required by the Accreditation Council for Graduate Medical Education (ACGME), on postoperative outcomes. MATERIALS AND METHODS: The divisions of General and Vascular Surgery at the Michael E. DeBakey Houston Veteran Affairs Medical Center implemented a limited work hours schedule effective October 1, 2002. We compared the rate of postoperative morbidity and mortality before and after the new schedule. Clinical data were collected by the VA National Surgical Quality Improvement Program (NSQIP) for the periods of October 1, 2001 to September 30, 2002 (preintervention), and October 1, 2002 to September 30, 2003 (postintervention). We assessed risk-adjusted observed to expected (O/E) ratios of mortality and prespecified postoperative morbidity for each study period. RESULTS: In the preintervention period, there were 405 general surgery and 202 vascular surgery cases as compared to 382 and 208 cases, respectively in the postintervention period. There were no significant differences in mortality O/E ratios between the pre- and postintervention periods (0.63 versus 0.60 in general surgery; 0.78 versus 0.81 in vascular surgery; P = 0.90 and 0.94, respectively) or in morbidity O/E ratios (1.06 versus 1.27 in general surgery; 1.47 versus 1.50 in vascular surgery; P = 0.20 and 0.90, respectively). CONCLUSION: The restricted resident work hour schedule in general and vascular surgery in our facility did not significantly affect postoperative outcomes.     

Does kidney transplantation with multiple arteries affect graft survival?

Introduction

We compared short- and long-term outcomes of renal transplants with single versus multiple arteries.

Patients and methods

We retrospectively analyzed data from kidney transplants from 208 living donors performed between 1994 and 2010. Renal grafts were divided into two groups: single renal artery (n = 164) versus multiple renal arteries (n = 44). The groups were compared regarding early and late vascular and urological complications. Patient and graft survivals were compared using Kaplan-Meier survivorship curves with comparisons using the log-rank test.

Results

Both groups were comparable regarding acute rejection episodes, posttransplant hypertension, postsurgery renal artery stenosis, and urologic complications. Only hemorrhagic complications and renal artery thrombosis were significantly higher in the multiple renal arteries group (P = .027 and .03, respectively). Warm ischemia time was significantly longer in the multiple renal arteries group without any influence on the incidence of acute tubular necrosis (P = .2). Mean creatinine clearance at 1 year was 65 versus 50 mL/min/1.73 m² (P = .5) and at 5 years, 60 versus 55 mL/min/1.73 m² (P = .1) for the single versus multiple renal arteries groups, respectively. Return to hemodialysis was necessary for 18.8% of the single and 16.1% of the multiple renal arteries group.

Conclusion

The use of an allograft with multiple renal arteries is a safe, successful surgical procedure, that does not influence patient or graft survivals or increase surgical complication rates provided the surgical team is evolved with technical skill.     

Complete versus partial excision of infected arteriovenous grafts: Does remnant graft material impact outcomes?

ObjectiveInfected arteriovenous grafts necessitate intervention to obtain source control. However, excising the graft material can be challenging and can lead to complications. Leaving a cuff of graft at the sites of anastomosis allows for the avoidance of potential risks. However, it is unclear whether doing so places patients at risk of recurrent graft infection. The purpose of the present study was to investigate the effect of complete vs partial excision of infected arteriovenous prosthetic dialysis access grafts.MethodsThe data from all patients who had undergone surgical intervention for infected arteriovenous grafts at a single institution were retrospectively reviewed. The patients were grouped according to intervention type: complete excision and partial excision of arteriovenous prosthetic grafts. Partial excisions were further substratified based on whether flow had been restored through the arteriovenous access. The primary outcome was freedom from subsequent intervention for infection, defined as the number of days from excision to subsequent reoperation for reinfection. Freedom from infection was analyzed using the Kaplan-Meier method.ResultsA total of 117 patients had undergone surgical intervention for 122 infected arteriovenous grafts from 2003 to 2016. Of these 117 patients, 79 (64.8%) had undergone partial excision of infected arteriovenous grafts, and 43 (35.2%) had undergone complete excision with vascular repair. Within the partial excision cohort, 71 infected arteriovenous grafts (58.2%) were not flow restored and 8 (6.6%) were flow restored using either prosthetic or autogenous interpositions. The median follow-up time was 2.4 years (interquartile range, 0.6-4.5 years). The most common causative organisms included methicillin-resistant Staphylococcus aureus (n = 34; 27.9%), methicillin-sensitive S. aureus (n = 17; 13.9%), and S. epidermidis (n = 15; 12.3%). The recurrent infection rate in the partial excision group was 16.5% (n = 13) compared with 2.3% (n = 1) in the complete excision group. In the flow-restored subcohorts, those with restoration using prosthetic interposition grafts had the greatest reinfection rate at 57.1% (n = 4), and those with restoration using autogenous conduits did not experience reinfection (P = .033).ConclusionsIncomplete excision of infected arteriovenous prosthetic grafts was associated with a higher rate of reinfection compared with complete graft excision. Complete excision presents technical challenges but could provide superior source control in managing infected dialysis access. Complete excision with vascular reconstruction should be performed when possible to avoid leaving remnant prosthetic material.     

Does pretransplant obesity affect the outcome in kidney transplant recipients?

The effect of obesity on renal transplant outcome remains unclear due to conflicting published studies. The purpose of this study was to assess whether obesity affects the outcome in renal transplant patients. METHODS: We retrospectively analyzed 33 obese (BMI >30; mean = 34.1 +/- 3.68; group I) and 35 nonobese (BMI < or = 30; mean = 23.6 +/- 3.18; group II) renal transplants performed at our center between March 1999 to December 2002. These two groups were well matched with respect to age, sex, donor source, hypertension, diabetes, ischemic heart disease, hyperlipidemia, native kidney disease (PCKD, 6 vs 4; diabetic, 5 vs 4; glomerulonephritis, 6 vs 7; FSGS, 2 vs 2 and IgA, 2 vs 7), HLA mismatch and immunosuppressants medications (Neoral, 21 vs 25; tacrolimus, 11 vs 10; Cellcept, 28 vs 31; Prednisone, 33 vs 35; ATG, 7 vs 8; Basiliximab, 14 vs 13 and Rapamycin, 5 vs 2, groups I and II, respectively). Follow-up was from 7 months to 4.4 years. RESULTS: Significant differences were noted in operating time, wound infection, perinephric hematoma, lymphocele, and number of hospital days. There were no significant differences between the two groups in the incidence of wound dehiscence, deep vein thrombosis, pulmonary embolism, atelectasis, urine leak, delayed graft function, acute rejection rate, and the following posttransplant variables: diabetes mellitus, myocardial infarction, hyperlipidemia, hypertension, and incisional hernia. We conclude that obesity significantly increases operating time, wound complications, and hospitalizations.     

Review of nutritional assessment and clinical outcomes in pediatric surgical patients: Does preoperative nutritional assessment impact clinical outcomes?

Introduction

Malnourished adult patients who undergo surgical procedures tend to have worse clinical outcomes compared to well-nourished patients. In the pediatric surgical patient, nutritional assessment is considered a critical aspect of the initial evaluation, but a correlation between preoperative malnutrition and poor surgical outcomes is not clear. We hypothesized that an evidence-based review would reveal that measures of nutritional assessment in children would not correlate pre-operative malnutrition with poor surgical outcomes.

Materials and Methods

A search of major English language medical databases (Medline, Cochrane, SCOPUS) was conducted for the key words nutritional assessment, pediatric, children, surgery, and outcomes. All methods of nutritional assessment in pediatric surgery were evaluated for their relevance and relation to outcomes after surgery. The Oxford Center for Evidence Based Medicine (CEBM) classification for levels of evidence was used to develop grades of clinical recommendation for each variable studied.

Results

35 articles were evaluated after an exhaustive literature search, of which six met inclusion criteria for this review. There is a paucity of high quality evidence correlating preoperative malnutrition in pediatric surgical patients with clinical outcomes. Factors contributing to the low level of evidence include a lack of high quality randomized controlled trials, a lack of consensus in study design and methods, and utilization of incongruous methods of nutritional assessment, including methods that may be unproven in the study population.

Conclusion

Larger multi center randomized studies are needed to offer higher level of evidence to support nutritional intervention prior to major elective pediatric surgery.     

Patient and graft survival in older kidney transplant recipients: does age matter?

An increasing gap between supply and demand of donor kidneys for transplantation exists. There is concern regarding the allocation of scarce organs to elderly patients, because the benefit obtained by the transplant may be less in elderly compared with younger recipients. It was the objective of this study to determine differences in patient and organ survival between organ recipients >65 yr and 50 to 64 yr of age at transplantation. A retrospective cohort of 627 patients >50 yr who received a kidney transplant between 1993 and 2000 was assembled. Detailed information on patient demographics, comorbidities, and immunological and donor characteristics was ascertained before transplantation. Five-year patient and graft survival were evaluated by Kaplan-Meier survival curves and multivariate Cox proportional-hazard models. Five-year patient mortality was similar between patients aged >65 and 60 to 64 at transplantation (relative risk [RR] = 1.07; 95% confidence interval [CI], 0.66 to 1.74). Patients aged 50 to 59 yr showed a clear trend toward lower 5-yr mortality (RR = 0.66; 95% CI, 0.43 to 1.03). Compared with patients >65 yr, 5-yr graft loss was not different in patients aged 60 to 64 (RR = 1.28; 95% CI, 0.82 to 2.02) or those aged 50 to 59 yr at transplantation (RR = 1.02; 95% CI, 0.68 to 1.53). After thorough control for confounding, 5-yr graft survival was not materially different by age group. Discrimination against older candidates for kidney transplantation on age-related grounds alone is not warranted.     

Does the KDIGO CKD risk stratification based on GFR and proteinuria predict kidney graft failure?

Purpose

The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guidelines on chronic kidney disease (CKD) introduced risk classes for adverse outcome based on estimated glomerular filtration rate (eGFR) and albuminuria categories (low—LR, moderately—MR, high—HR, very high risk—VHR). We aimed to investigate if such risk stratification is suitable in kidney transplant (KTx) recipients.

Methods

This single-center prospective study enrolled 231 prevalent KTx recipients [36 (34–48) years, 62 % male, eGFR 53.7 (50.9–56.4) mL/min]. The patients were stratified in risk classes in January 2011; clinical and laboratory data were collected every 6 months till June 2013. Individual slope of linear regression of all eGFR and time-averaged proteinuria (TAP) were computed. The composite endpoint was defined as >30 % decline in eGFR from 6 months after KTx to June 2013, dialysis initiation or death.

Results

Fifty-one patients reached the endpoint. They were younger, more often female, donor specific anti-HLA antibodies positive, noncompliant and smokers. TAP was 4 time greater (p < 0.0001) and eGFR abruptly declined [eGFR slope: ?3.17 (?4.13 to ?2.21) vs. 0.81 (0.45–1.3) mL/min per year, p < 0.0001] in the endpoint group. At baseline: 36 % LR, 23 % MR, 23 % HR and 18 % VHR, without differences between the groups. In the binary logistic regression model, VHR as compared to the other risk classes was an independent risk factor for poorer outcome. The final model also included female gender, cardiovascular events, smoking, GFR slope and BK virus infection.

Conclusions

Risk group stratification according to KDIGO guideline on CKD may prove useful in predicting graft outcome, but this should be confirmed in larger cohorts.     

Long-term kidney transplant graft survival—Making progress when most needed

Current short-term kidney post–transplant survival rates are excellent, but longer-term outcomes have historically been unchanged. This study used data from the national Scientific Registry of Transplant Recipients (SRTR) and evaluated 1-year and 5-year graft survival and half-lives for kidney transplant recipients in the US. All adult (≥18 years) solitary kidney transplants (n = 331,216) from 1995 to 2017 were included in the analysis. Mean age was 49.4 years (SD +/-13.7), 60% male, and 25% Black. The overall (deceased and living donor) adjusted hazard of graft failure steadily decreased from 0.89 (95%CI: 0.88, 0.91) in era 2000–2004 to 0.46 (95%CI: 0.45, 0.47) for era 2014–2017 (1995–1999 as reference). Improvements in adjusted hazards of graft failure were more favorable for Blacks, diabetics and older recipients. Median survival for deceased donor transplants increased from 8.2 years in era 1995–1999 to an estimated 11.7 years in the most recent era. Living kidney donor transplant median survival increased from 12.1 years in 1995–1999 to an estimated 19.2 years for transplants in 2014–2017. In conclusion, these data show continuous improvement in long-term outcomes with more notable improvement among higher-risk subgroups, suggesting a narrowing in the gap for those disadvantaged after transplantation.     

Does age affect the outcomes and management of pediatric appendicitis?

Purpose

Although it is recognized that younger children have higher appendiceal perforation rates, little is known about the effect of age on postoperative morbidity. The purpose of this study was to determine whether age affects the outcome and management of pediatric appendicitis.

Methods

A retrospective review of all patients 14 years and younger who were treated for appendicitis over a 10-year period was performed. Study outcomes included 30-day postoperative morbidity, use of laparoscopy, and length of hospitalization (LOH). Postoperative morbidity included rates of wound infection, postoperative abscess drainage, and readmission. Patients were categorized into 3 age groups: young (≤5 years), middle (6-9 years), and older (≥10 years). Data for univariate associations were analyzed using χ² and Wilcoxon rank sum tests and reported as medians with interquartile ranges (IQR). Study outcomes were also analyzed using multivariable regression.

Results

Overall, 5894 patients were identified. Median age was 10.3 years (IQR 7.3-12.5), and 61% were boys. The perforation rate was highest for patients 5 years and younger (≤5 years, 51%; 6-9 years, 32%; ≥10 years, 27%; P < .0001). Multivariable analysis demonstrated that although the need for postoperative abscess drainage was greatest in older children (10-14 years), the readmission rate and LOH was highest in the youngest children (≤5 years). Wound infection rates were similar across all age groups.

Conclusions

Although older children had a higher risk of abscess drainage, younger children were more likely to have perforated appendicitis, be readmitted, and have longer LOH. Management of appendicitis differed according to age. Laparoscopic appendectomy was more frequently performed in older children, whereas the youngest children were more likely to be treated nonoperatively.     

Does calcium channel blocker improvement of perfusion impact the functioning of kidney graft in early period after transplantation?

The aim of the study was to evaluate the influence of reduced vascular resistance following calcium channel blocker verapamil administration on kidney function at 3 months after transplantation. A group of 48 kidneys received 100 microg verapamil by injection directly into renal artery before starting perfusion. The control group included 48 paired kidneys without verapamil addition. Calcium channel blocker therapy with verapamil greatly decreased renal vascular resistance but it did not affect graft function. Administration of calcium channel blockers improved kidney function in the early period after transplantation. A better-functioning graft seems to be based more on metabolic than hemodynamic effects.