Vascular Access-Related Distal Ischemia Requiring Intervention: Frequency, Risk Factors, and Consequences

BACKGROUND

Distal ischemia is a rare complication in patients undergoing placement of an arteriovenous (AV) fistula or AV graft. There are limited studies on its frequency, risk factors, clinical consequences, or feasibility of subsequent access.

METHODS

A prospective vascular access database from a large academic medical center was queried retrospectively to identify 1498 patients (mean age 56±15 years, 48% female patients, 73% Black patients) undergoing placement of at least one vascular access from 2011 to 2020. For patients who developed access-related distal ischemia requiring surgical intervention, we determined the frequency of distal ischemia, clinical risk factors, and subsequent outcomes.

RESULTS

Severe access-related distal ischemia occurred in 28 patients (1.9%; 95% confidence interval, 1.3% to 2.7%). The frequency was 0.2% for forearm AV fistulas, 0.9% for upper arm AV fistulas, 2.4% for forearm AV grafts, 2.2% for upper arm AV grafts, and 2.8% for thigh AV grafts. Risk factors independently associated with distal ischemia included female sex (odds ratio [OR], 3.64 [95% confidence interval, 1.52 to 8.72]), peripheral vascular disease (OR, 6.28 [2.84 to 13.87]), and coronary artery disease (OR, 2.37 [1.08 to 5.23]). Surgical interventions included ligation, excision, plication (banding), and other surgical procedures. Five patients developed tissue necrosis. A subsequent AV graft was placed in 13 patients, of whom only one (8%) developed distal ischemia requiring intervention.

CONCLUSIONS

Access-related distal ischemia requiring intervention was rare in this study and more common in women and patients with peripheral vascular disease or coronary artery disease. In some cases, a subsequent vascular access could be placed with a low likelihood of recurrent distal ischemia.

Predialysis Vascular Access Placement and Catheter Use at Hemodialysis Initiation

BACKGROUND

Current guidelines encourage placement of an arteriovenous (AV) fistula in patients with advanced CKD to avoid initiation of hemodialysis with a central venous catheter. However, the relative merits of predialysis placement of an AV fistula or graft have been poorly studied.

METHODS

This study included 380 patients (mean age 59±14 years, 73% Black patients, 51% male) from a large academic medical center who underwent predialysis placement of an AV fistula (286) or AV graft (94). The study quantified three end points: time from access placement to initiation of dialysis, likelihood of starting hemodialysis without a catheter, and number of vascular access procedures before dialysis initiation.

RESULTS

The eGFR at access surgery was <10, 10-14, and ≥15 ml/min per 1.73 m 2 in 87 (23%), 179 (47%), and 114 (30%) patients, respectively. The median time from access surgery to hemodialysis initiation was 69, 156, and 429 days in patients with an eGFR of <10, 10-14, and ≥15 ml/min per 1.73 m 2 , respectively ( P < 0.001). Hemodialysis was initiated within 2 years of access surgery in 298 (78%) of the patients. Catheter-free hemodialysis initiation was higher in patients with an AV graft versus an AV fistula when the eGFR was <10 ml/min per 1.73 m 2 (88% versus 43%; odds ratio [OR], 9.10 [95% confidence interval, 2.74 to 26.4]) and when the eGFR was 10-14 ml/min per 1.73 m 2 (88% versus 54%; OR, 6.05 [2.35 to 15.0]) but similar when the eGFR was ≥15 ml/min per 1.73 m 2 (90% versus 75%; OR, 3.00 [0.48 to 34.9]). Patients undergoing an AV fistula were more likely to undergo an angioplasty (11% versus 0%, P < 0.001), surgical access revision (26% versus 8%, P < 0.001), a second access placement (16% versus 6%, P = 0.02), and a catheter insertion (32% versus 11%, P < 0.001).

CONCLUSIONS

Among patients with CKD undergoing vascular access surgery when their eGFR was <15 ml/min per 1.73 m 2 , catheter use at dialysis initiation was much less likely when an AV graft, rather than an AV fistula, was placed.

Effects of a More Selective Arteriovenous Fistula Strategy on Vascular Access Outcomes

SIGNIFICANCE STATEMENT

The optimal choice of vascular access for patients undergoing hemodialysis-arteriovenous fistula (AVF) or arteriovenous graft (AVG)-remains controversial. In a pragmatic observational study of 692 patients, the authors found that among patients who initiated hemodialysis with a central vein catheter (CVC), a strategy that maximized AVF placement resulted in a higher frequency of access procedures and greater access management costs for patients who initially received an AVF than an AVG. A more selective policy that avoided AVF placement if an AVF was predicted to be at high risk of failure resulted in a lower frequency of access procedures and access costs in patients receiving an AVF versus an AVG. These findings suggest that clinicians should be more selective in placing AVFs because this approach improves vascular access outcomes.

BACKGROUND

The optimal choice of initial vascular access-arteriovenous fistula (AVF) or graft (AVG)-remains controversial, particularly in patients initiating hemodialysis with a central venous catheter (CVC).

METHODS

In a pragmatic observational study of patients who initiated hemodialysis with a CVC and subsequently received an AVF or AVG, we compared a less selective vascular access strategy of maximizing AVF creation (period 1; 408 patients in 2004 through 2012) with a more selective policy of avoiding AVF creation if failure was likely (period 2; 284 patients in 2013 through 2019). Prespecified end points included frequency of vascular access procedures, access management costs, and duration of catheter dependence. We also compared access outcomes in all patients with an initial AVF or AVG in the two periods.

RESULTS

An initial AVG placement was significantly more common in period 2 (41%) versus period 1 (28%). Frequency of all access procedures per 100 patient-years was significantly higher in patients with an initial AVF than an AVG in period 1 and lower in period 2. Median annual access management costs were significantly higher among patients with AVF ($10,642) versus patients with AVG ($6810) in period 1 but significantly lower in period 2 ($5481 versus $8253, respectively). Years of catheter dependence per 100 patient-years was three-fold higher in patients with AVF versus patients with AVG in period 1 (23.3 versus 8.1, respectively), but only 30% higher in period 2 (20.8 versus 16.0, respectively). When all patients were aggregated, the median annual access management cost was significantly lower in period 2 ($6757) than in period 1 ($9781).

CONCLUSIONS

A more selective approach to AVF placement reduces frequency of vascular access procedures and cost of access management.

Study protocol of a randomized controlled trial of fistula vs. graft arteriovenous vascular access in older adults with end-stage kidney disease on hemodialysis: the AV access trial

BACKGROUND

Treatment of end-stage kidney disease (ESKD) with hemodialysis requires surgical creation of an arteriovenous (AV) vascular access-fistula (AVF) or graft (AVG)-to avoid (or limit) the use of a central venous catheter (CVC). AVFs have long been considered the first-line vascular access option, with AVGs as second best. Recent studies have suggested that, in older adults, AVGs may be a better strategy than AVFs. Lacking evidence from well-powered randomized clinical trials, integration of these results into clinical decision making is challenging. The main objective of the AV Access Study is to compare, between the two types of AV access, clinical outcomes that are important to patients, physicians, and policy makers.

METHODS

This is a prospective, multicenter, randomized controlled trial in adults ≥ 60 years old receiving chronic hemodialysis via a CVC. Eligible participants must have co-existing cardiovascular disease, peripheral arterial disease, and/or diabetes mellitus; and vascular anatomy suitable for placement of either type of AV access. Participants are randomized, in a 1:1 ratio, to a strategy of AVG or AVF creation. An estimated 262 participants will be recruited across 7 healthcare systems, with average follow-up of 2 years. Questionnaires will be administered at baseline and semi-annually. The primary outcome is the rate of CVC-free days per 100 patient-days. The primary safety outcome is the cumulative incidence of vascular access (CVC or AV access)-related severe infections-defined as access infections that lead to hospitalization or death. Secondary outcomes include access-related healthcare costs and patients' experiences with vascular access care between the two treatment groups.

DISCUSSION

In the absence of studies using robust and unbiased research methodology to address vascular access care for hemodialysis patients, clinical decisions are limited to inferences from observational studies. The goal of the AV Access Study is to generate evidence to optimize vascular access care, based on objective, age-specific criteria, while incorporating goals of care and patient preference for vascular access type in clinical decision-making.

TRIAL REGISTRATION

This study is being conducted in accordance with the tenets of the Helsinki Declaration, and has been approved by the central institutional review board (IRB) of Wake Forest University Health Sciences (approval number: 00069593) and local IRB of each participating clinical center; and was registered on Nov 27, 2020, at ClinicalTrials.gov (NCT04646226).

Factors associated with healing, reoperation and continence disturbance in patients following surgery for fistula-in-ano

AIM

Fistula-in-ano (FIA) is associated with high treatment costs and has a deleterious impact on quality of life. A wide range of healing, incontinence and recurrence rates have been reported. This study aimed to identify operative, patient and disease factors that influence these outcomes after surgery for FIA.

METHOD

An observational cohort study of consecutive patients who were managed for FIA at a tertiary colorectal practice (1999-2019) was performed. Outcome measures included healing, impaired continence and the need to reoperate. Clinico-pathological variables, including patient comorbidities, fistula anatomy and operative approach, were assessed for their association with these outcomes.

RESULTS

Some 411 procedures were performed on 263 patients [median age 41.8 years (range 17.8-79.7 years), 184 men (70.0%)]. Some 77.9% of patients achieved complete healing, 9.5% experienced some deterioration in continence postoperatively and 37.6% required reoperation at a median time of 19.0 weeks. Poorer healing was associated with Crohn's disease, high trans-sphincteric fistulas, extrasphincteric fistulas and steroid usage. Poorer continence was associated with female sex, age > 40 years, posterior location, suprasphincteric fistulas, seton insertion and having more than three subsequent procedures. The need to reoperate was associated with female sex, high trans-sphincteric fistulas, suprasphincteric fistulas, inflammatory bowel disease and previous operations for FIA.

CONCLUSION

Minimizing recurrence of FIA and preservation of continence can be competing management goals. More than one in three patients require reoperation, one in five fails to heal completely and one in ten suffers worsened continence following surgery. Awareness of the factors that contribute to these outcomes is important to the process of informed consent and managing patient expectations before surgery.

A systematic review and meta-analysis of biofeedback therapy for dyssynergic defaecation in adults

BACKGROUND

Dyssynergic defaecation is a common form of functional constipation that responds poorly to conservative interventions. This systematic review and meta-analysis assesses the effectiveness of biofeedback therapy for dyssynergic defaecation using global clinical improvement as the primary outcome, and resolution of the dyssynergic pattern on anorectal physiology and quality of life as secondary outcomes.

METHODS

MEDLINE, EMBASE, CENTRAL, PsychInfo, CINAHL, Scopus, and Web of Science were searched from inception to March 2019 using a predefined strategy. Randomised controlled trials of adult patients with dyssynergic defaecation and a biofeedback treatment arm were eligible for review. Studies including patients with secondary forms of constipation were excluded. Data abstraction and risk of bias assessments were conducted by consensus between two authors.

RESULTS

Eleven trials including 725 participants were included in the narrative review. Sixty-three percent of patients treated with biofeedback reported clinical improvement. Six studies included in the meta-analysis showed biofeedback superior to non-biofeedback therapy for the primary outcome (OR 3.63, CI 1.10-11.93, p = 0.03). Heterogeneity between trials and overall risk of bias was high.

CONCLUSIONS

Biofeedback therapy is recommended for patients referred to tertiary units with dyssynergic defaecation who fail conservative therapy. Future research should be directed towards identifying validated outcomes and the optimum method for delivering biofeedback therapy. Home biofeedback therapy may improve accessibility and recruitment to future clinical trials.

The role of MRI pelvimetry in predicting technical difficulty and outcomes of open and minimally invasive total mesorectal excision: a systematic review

BACKGROUND

The difficulty of performing total mesorectal excision (TME) for rectal cancer partly relies on the surgeon's subjective assessment of the individual patient's pelvic anatomy and tumour characteristics, which generally influences the choice of platform used (open, laparoscopic, robotic or trans-anal surgery). Recent studies have found associations between several anatomical pelvic measurements and surgical difficulty. The aim of this study was to systematically review existing data reporting the use of magnetic resonance imaging (MRI)-based pelvic measurements to predict technical difficulty and outcomes of TME, and determine whether pelvimetry could optimise patient-specific selection of a particular surgical approach.

METHODS

MEDLINE, Embase and Cochrane Library databases were systematically searched for studies reporting MRI-based pelvic measurements in patients undergoing surgery for rectal cancer, and the effect of these measurements on surgical difficulty.

RESULTS

Eleven studies reporting the association between MRI-pelvimetry measurements and rectal cancer surgical outcomes were included. Indicators for surgical difficulty used in the included studies were involved circumferential resection margin, longer operative time, incomplete TME, higher blood loss, anastomotic leak, conversion to open surgery and overall complications. Bony pelvic measurements which were associated with increased surgical difficulty in more than one study were a smaller interspinous distance, a smaller intertubercle distance, a smaller pelvic inlet and larger pubic tubercle height. Two studies identified larger mesorectal fat area as a predictor of surgical difficulty.

CONCLUSIONS

Bony pelvic measurements may predict surgical difficulty during TME, however, use of different indicators of difficulty limit comparison between studies. Early data suggest MRI soft tissue measurements may predict surgical difficulty and warrants further investigation.

Randomized clinical trial of the effect of intraoperative humidified carbon dioxide insufflation in open laparotomy for colorectal resection

Background

Animal studies have shown that peritoneal injury can be minimized by insufflating the abdominal cavity with warm humidified carbon dioxide gas.

Methods

A single‐blind RCT was performed at a tertiary colorectal unit. Inclusion criteria were patient aged 18 years and over undergoing open elective surgery. The intervention group received warmed (37°C), humidified (98 per cent relative humidity) carbon dioxide (WHCO₂ group). Multiple markers of peritoneal inflammation and oxidative damage were used to compare groups, including cytokines and chemokines, apoptosis, the 3‐chlorotyrosine/native tyrosine ratio, and light microscopy on peritoneal biopsies at the start (T₀) and end (T_end) of the operation. Postoperative clinical outcomes were compared between the groups.

Results

Of 40 patients enrolled, 20 in the WHCO₂ group and 19 in the control group were available for analysis. A significant log(T_end/T₀) difference between control and WHCO₂ groups was documented for interleukin (IL) 2 (5·3 versus 2·8 respectively; P = 0·028) and IL‐4 (3·5 versus 2·0; P = 0·041), whereas apoptosis assays documented no significant change in caspase activity, and similar apoptosis rates were documented along the peritoneal edge in both groups. The 3‐chlorotyrosine/tyrosine ratio had increased at T_end by 1·1‐fold in the WHCO₂ group and by 3·1‐fold in the control group. Under light microscopy, peritoneum was visible in 11 of 19 samples from the control group and in 19 of 20 samples from the WHCO₂ group (P = 0·006). The only difference in clinical outcomes between intervention and control groups was the number of days to passage of flatus (2·5 versus 5·0 days respectively; P = 0·008).

Conclusion

The use of warmed, humidified carbon dioxide appears to reduce some markers related to peritoneal oxidative damage during laparotomy. No difference was observed in clinical outcomes, but the study was underpowered for analysis of surgical results. Registration number: NCT02975947 ( http://www.clinicaltrials.gov/).

Recurrence and cancer-specific death after adjuvant chemotherapy for Stage III colon cancer

AIM

The recommended standard of care for patients after resection of Stage III colon cancer is adjuvant 5-fluorouracil based chemotherapy - FOLFOX (fluorouracil, leucovorin with oxaliplatin) - or CAPOX (capecitabine, oxaliplatin). This may be modified in older patients or depending on comorbidity. This has been challenged recently as the apparent benefit of adjuvant chemotherapy may arise from improvements in surgery or preoperative imaging or pathology staging. This study compares recurrence and colon-cancer-specific death between patients who received postoperative adjuvant chemotherapy and those who did not.

METHOD

Prospectively recorded data from 363 consecutive patients who had a resection for Stage III colonic adenocarcinoma between 1995 and 2010 inclusive were analysed. Surviving patients were followed for at least 5 years. The suitability of patients for chemotherapy was discussed routinely at multidisciplinary team meetings. The incidence of recurrence and colon-cancer-specific death was evaluated by competing risk methods.

RESULTS

After adjustment for the competing risk of non-colorectal cancer death, there was no significant difference in recurrence between the 204 patients who received chemotherapy and the 159 who did not [hazard ratio (HR) 0.94, 95% CI 0.66-1.32, P = 0.700) and no significant difference in colon-cancer-specific death (HR 0.73, 95% CI 0.50-1.04, P = 0.084; HR 0.88, 95% CI 0.57-1.36, P = 0.577 after adjustment for relevant covariates).

CONCLUSION

These findings question the routine use of chemotherapy after complete mesocolic excision for Stage III colon cancer. Recurrence and cancer-specific death, assessed by competing risk methods, should be the standard outcomes for evaluating the effectiveness of adjuvant chemotherapy after potentially curative resection.

Treatment of anal fissure: a survey of surgical practice in Australia and New Zealand

AIM

The aim was to determine whether or not the clinical management of anal fissure in Australia and New Zealand accords with published guidelines.

METHODS

A comprehensive survey based on common clinical scenarios was distributed to 206 colorectal surgeons in Australia and New Zealand.

RESULTS

The response rate was 44% (91 surgeons). For 19 topic areas, only seven (37%) reached consensus (defined as > 70% majority opinion). Of these, six (86%) agreed with guideline recommendations. Twelve (63%) topic areas demonstrated community equipoise (defined as less than or equal to 70% majority opinion), of which five (42%) agreed with guideline recommendations and seven (58%) disagreed with guidelines. Of the seven topics that disagreed with guidelines, three were based on moderate quality evidence (first line management of acute anal fissure in a young patient, fissure healing and faecal incontinence rates following anocutaneous flap) and four were based on low quality evidence (length of sphincter division during a lateral sphincterotomy in women, management of chronic low-pressure anal fissures postpartum, fissure healing rate following anoplasty with botulinum toxin or sphincterotomy and faecal incontinence rates following repeat sphincterotomy for recurrence). Consensus and/or agreement with guidelines were more prevalent in management when medical therapy failed.

CONCLUSION

While areas of consensus mostly agreed with guideline recommendations, there remain many areas of community equipoise which warrant further research.

Rubber Band Ligation of Hemorrhoids is often a Necessary Complement in the Management of Hemorrhagic Radiation Proctitis

BACKGROUND

Management of radiation proctitis presents a treatment challenge. Limited data exist on the management of symptomatic hemorrhoids in radiated patients. This study aims to present a practical approach to the management of radiation proctitis, particularly in patients with synchronous hemorrhoids.

METHODS

A total of 52 consecutive cases of radiation proctitis managed between September 1999 and October 2017 were retrospectively reviewed. The primary treatment was formalin application, plus rubber band ligation in conjunction with formalin when hemorrhoids were a significant component of bleeding, and occasionally argon plasma coagulation.

RESULTS

The primary indication for radiotherapy was for the treatment of prostate cancer (71%), anal squamous cell carcinoma (10%), and gynecological malignancies (18%). More than half of the patients (52%) presented with radiation proctitis and concomitant internal hemorrhoids. The hemorrhoids were managed with rubber band ligation (56%) and stapled hemorrhoidectomy (7%), at the same procedure as formalin application. At a median follow-up of 12 months, no recurrent rectal bleeding occurred, and no further treatment was needed for most patients. One patient experienced a short period of perianal pain, which was treated with analgesics.

CONCLUSION

Formalin application has consistently demonstrated an excellent cure rate and safety profile comparable with the published results as a primary treatment for radiation proctitis. The prolapse of irradiated mucosa over the internal hemorrhoids appears to exacerbate bleeding. Local hemorrhoid treatment is often required as an adjunct in the management of these patients.

Decreasing deceased donor transplant rates among children (≤6 years) under the new kidney allocation system

The Kidney Allocation System (KAS) was implemented in December 2014 with unknown impact on the pediatric waitlist. To understand the effect of KAS on pediatric registrants, deceased donor kidney transplant (DDKT) rate was assessed using interrupted time series analysis and time-to-event analysis. Two allocation eras were defined with an intermediary washout period: Era 1 (01/01/2013-09/01/2014), Era 2 (09/01/2014-03/01/2015), and Era 3(03/01/2015-03/01/2017). When using Cox proportional hazards, there was no significant association between allocation era and DDKT likelihood as compared to Era 1 (Era 3: aHR: 1.07, 95% CI: 0.97-1.18, P = .17). However, this was not consistent across all subgroups. Specifically, while highly sensitized pediatric registrants were consistently less likely to be transplanted than their less sensitized counterparts, this disparity was attenuated in Era 3 (Era 1 aHR: 0.04, 95%CI: 0.01-0.14, P < .001; Era 3 aHR: 0.33, 95% CI: 0.21-0.53, P < .001) whereas the youngest registrants aged 0-6 experienced a 21% decrease in DDKT likelihood in Era 3 as compared to Era 1 (aHR: 0.79, 95% CI: 0.64-0.98, P = .03). Thus, while overall DDKT likelihood remained stable with the introduction of KAS, registrants ≤ 6 years of age were disadvantaged, warranting further study to ensure equitable access to transplantation.

Gum chewing aids bowel function return and analgesic requirements after bowel surgery: a randomized controlled trial

AIM

The aim was to compare the effectiveness of chewing sugar-free gum after bowel resection on bowel function and length of stay.

METHOD

This was a randomized controlled trial of patients undergoing elective open or laparoscopic bowel surgery, who were allocated into two groups: a chewing gum group (CG); or a nonchewing gum group (NG). Primary outcomes were time to discharge (length of hospital stay [LOS]), time to first flatus (TFF) and time to first bowel motion (TBM). Secondary outcomes were complication rates, pain and total morphine equivalent (TMEq) medication for 7 days after the procedure.

RESULTS

Between 2010 and 2013, 162 patients were randomized; four were excluded, leaving 158 in the study (82 in the CG and 76 in the NG). There was no difference in LOS between the CG (5.8 days) and the NG (6.1 days) (P = 0.403) or in the median TFF between the CG (42.0 h) and the NG (58.0 h) (P = 0.076). The median TBM was lower in the CG (40.0 h) than in the NG (90.0 h) (P = 0.002). There was no difference in intra-operative complications between the CG (9%) and the NG (9%) (P = 0.901) or in early postoperative complications (44% for CG and 55% for NG) (P = 0.131). There was no difference in TMEq at 24 h postprocedure, but the CG had reduced TMEq from days 2 to 7 post procedure and for the 7-day total. Pain was higher among patients in the NG on day 3.

CONCLUSION

Chewing sugar-free gum resulted in an earlier return to bowel function and decreased analgesic requirements. There was no decrease in overall LOS or postoperative complications.

Randomized controlled trial of colonic stent insertion in non-curable large bowel obstruction: a post hoc cost analysis

AIM

In view of the increasing burden on the healthcare system, this study aims to perform a cost-effectiveness analysis of the management of incurable large bowel obstruction comparing the cost of a stent vs surgery.

METHOD

A prospective randomized controlled trial was conducted at two major teaching hospitals in Australia between September 2006 and November 2011. Fifty-six patients with malignant incurable large bowel obstruction were randomized to stent insertion or surgical decompression, of whom 52 were included in the final analysis. Data were collected at all points during the patient journey and quality of life data were obtained by patient surveys. All data points were analysed and a cost-effectiveness study was performed to compare the costs between the two treatment groups.

RESULTS

Stenting as a procedure was significantly more expensive than surgery (A$4462.50 vs A$3251.50; P < 0.001). Post-procedure stay for stented patients was significantly lower (median 7 vs 11 days; P = 0.03). Combined costs of stent group ward stay, multidisciplinary team discussion and complication management were significantly lower (P = 0.013). Overall cost difference between the two treatment groups was A$3902.44 (P = 0.101). European Quality of Life - 5 Dimensions (EQ-5D) scores for the first 4 weeks gave mean area under the curve adjusted weeks of 2.411 vs 2.271 for the stent and surgery groups respectively (P = 0.603). The incremental cost-effectiveness ratio between the surgery and the stent group was $22 955.53 in favour of stenting.

CONCLUSIONS

Treatment with stenting is cheaper than open surgery and provides quicker discharge from hospital.

A randomized controlled trial of four different regimes of biofeedback programme in the treatment of faecal incontinence

AIM

Biofeedback is an established, effective and non-invasive treatment for faecal incontinence (FI). The aim was to compare the effectiveness of four different biofeedback treatment regimes.

METHOD

This was a randomized control trial of patients with FI, stratified into two groups (metropolitan and rural) and then randomized into two subgroups (groups 1 and 2 within metropolitan, groups 3 and 4 within rural) with varying face-to-face and telephone biofeedback components. All patients received standardized counselling and education, dietary modification and the use of anti-diarrhoeal medications. Group 1 received four monthly face-to-face biofeedback treatments, groups 2 and 3 received one face-to-face biofeedback followed by telephone biofeedback and group 4 received a one-off face-to-face biofeedback treatment. Primary outcomes were patient-assessed severity of FI and quality of life as assessed by the 36-item Short Form Health Survey and direct questioning of objectives. Secondary outcomes included St Mark's incontinence score, anxiety, depression and anorectal physiology measures (resting, squeeze pressures; isotonic, isometric fatigue times).

RESULTS

Between 2006 and 2012, 351 patients were recruited. One patient died leaving 350 for analysis. 332 (95%) were women. Mean age was 60 (SD = 14). All groups had significant improvements in FI, quality of life, incontinence score and mental status (P < 0.001 each). There were no differences in improvements in FI between groups although patient satisfaction was less with reduced face-to-face contact. There were modest improvements in isotonic and isometric fatigue times suggesting improved sphincter endurance (both P < 0.001).

CONCLUSION

Biofeedback is effective for FI. Although face-to-face and telephone biofeedback is not necessary to improve FI, it is important for patient satisfaction.

The Clinical and Economic Effect of Vascular Access Selection in Patients Initiating Hemodialysis with a Catheter

Patients in the United States frequently initiate hemodialysis with a central venous catheter (CVC) and subsequently undergo placement of a new arteriovenous fistula (AVF) or arteriovenous graft (AVG). Little is known about the clinical and economic effects of initial vascular access choice. We identified 479 patients starting hemodialysis with a CVC at a large medical center (during 2004-2012) who subsequently had an AVF (n=295) or AVG (n=105) placed or no arteriovenous access (CVC group, n=71). Compared with patients receiving an AVG, those receiving an AVF had more frequent surgical access procedures per year (1.01 [95% confidence interval, 0.95 to 1.08] versus 0.62 [95% confidence interval, 0.55 to 0.70]; P<0.001) but a similar frequency of percutaneous access procedures per year. Patients receiving an AVF had a higher median annual cost (interquartile range) of surgical access procedures than those receiving an AVG ($4857 [$2523-$8835] versus $2819 [$1411-$4274]; P<0.001), whereas the annual cost of percutaneous access procedures was similar in both groups. The AVF group had a higher median overall annual access-related cost than the AVG group ($10,642 [$5406-$19,878] versus $6810 [$3718-$13,651]; P=0.001) after controlling for patient age, sex, race, and diabetes. The CVC group had the highest median annual overall access-related cost ($28,709 [$11,793-$66,917]; P<0.001), largely attributable to the high frequency of hospitalizations due to catheter-related bacteremia. In conclusion, among patients initiating hemodialysis with a CVC, the annual cost of access-related procedures and complications is higher in patients who initially receive an AVF versus an AVG.

Barriers to the management of obstructed defaecation according to colorectal surgeons

AIM

Obstructed defaecation (OD) has a high prevalence and high disease impact; however, patients often experience suboptimal management. This problem reflects the complex pathophysiology of OD as well as health service delivery factors. This study aimed to identify the factors that act as a barrier to effective management of OD as perceived by specialist colorectal surgeons treating this disorder.

METHOD

A postal questionnaire was administered to a bi-national sampling of colorectal specialists in Australia and New Zealand who were registered with their specialty society. Questions addressed variables relevant in OD management, including clinical access, decision-making, patient factors and surgeon experience and perceptions, and used Likert scales. Statistical analyses compared surgeon practice variables.

RESULTS

The response rate was 68.5% (n = 113). Most surgeons managed OD (94%), and preferred to treat OD patients themselves (87%); however, 33% of these respondents were dissatisfied with their management, 46% felt they lacked management expertise and 33% stated they had inadequate expertise in OD investigations. Clinical investigation services were more limited in private than public practice, and many surgeons lacked access to biofeedback (31%). Other barriers included heterogeneity in decision-making by surgeon age and practice location (P < 0.05), dual pathologies (e.g. irritable bowel syndrome) and psychological factors, and limited uptake of multidisciplinary services and standardized (Rome) diagnostic criteria.

CONCLUSION

Barriers to OD management include surgeon-specific factors, patient-specific factors and healthcare access factors. Increased utilization of pelvic floor and multidisciplinary services, increased training and standardization of OD investigations and improved access to specialist investigations and allied-health management services could improve outcomes for OD.

Predictors of Initiation for Predialysis Arteriovenous Fistula

BACKGROUND AND OBJECTIVES

The optimal timing of predialysis arteriovenous fistula surgery remains uncertain. We evaluated factors associated with hemodialysis initiation in patients undergoing predialysis arteriovenous fistula surgery and derived a model to predict future initiation of dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study retrospectively identified 308 patients undergoing predialysis arteriovenous fistula creation at a large medical center in 2006-2012 to determine whether they initiated hemodialysis. Multiple variable logistic regression analyzed which demographic and clinical factors predicted initiation of dialysis within 2 years of arteriovenous fistula surgery. A receiver operating characteristic area under the curve was used to quantify the predictive value of preoperative factors on the likelihood of initiating hemodialysis within 2 years.

RESULTS

Overall, hemodialysis was initiated within 6 months, 1 year, and 2 years in 119 (39%), 175 (57%), and 211 (68%) patients, respectively. Using multiple variable logistic regression, four factors were associated with hemodialysis initiation at 2 years: eGFR at access surgery (odds ratio, 0.45; 95% confidence interval, 0.31 to 0.64 per 5 ml/min per 1.73 m2; P<0.001), diabetes (odds ratio, 2.51; 95% confidence interval, 1.22 to 5.15; P=0.003), GFR trajectory (odds ratio, 1.54; 95% confidence interval, 1.09 to 2.17 per 3 ml/min per 1.73 m2 per year; P=0.01), and spot urine protein-to-creatinine ratio (odds ratio, 1.39; 95% confidence interval, 1.14 to 1.71 per 1 U; P<0.001). eGFR alone had a moderate predictive value for dialysis initiation (area under the curve =0.69; 95% confidence interval, 0.63 to 0.76; P<0.001), whereas the full model had a higher predictive value (area under the curve =0.83; 95% confidence interval, 0.77 to 0.88; P<0.001).

CONCLUSIONS

The likelihood of initiating hemodialysis within 2 years of predialysis arteriovenous fistula surgery is associated with eGFR at access surgery, diabetes, GFR trajectory, and magnitude of proteinuria. The combined use of all four variables improves the ability to predict future hemodialysis compared with the use of eGFR alone.

Preoperative Vascular Medial Fibrosis and Arteriovenous Fistula Development

BACKGROUND AND OBJECTIVES

Arteriovenous fistula maturation requires an increase in the diameter and blood flow of the feeding artery and the draining vein after its creation. The structural properties of the native vessels may affect the magnitude of these changes. We hypothesized that an increase in the collagen content of the vascular media (medial fibrosis) preoperatively would impair vascular dilation and thereby, limit the postoperative increase in arteriovenous fistula diameter and blood flow and clinical arteriovenous fistula maturation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We enrolled 125 patients undergoing arteriovenous fistula creation between October of 2008 and April of 2012 and followed them prospectively. Any consenting subject was eligible. Arterial and venous specimens were sampled during arteriovenous fistula surgery. Masson's trichrome-stained samples were used to quantify medial fibrosis. Arteriovenous fistula diameter and blood flow were quantified using 6-week postoperative ultrasound. Clinical arteriovenous fistula maturation was assessed using a predefined protocol. The association of preexisting vascular medial fibrosis with arteriovenous fistula outcomes was evaluated after controlling for baseline demographics, comorbidities, and the preoperative venous diameter.

RESULTS

The mean medial fibrosis was 69%±14% in the arteries and 63%±12% in the veins. Arterial medial fibrosis was associated with greater increases in arteriovenous fistula diameter (Δdiameter =0.58 mm; 95% confidence interval [95% CI], 0.27 to 0.89 mm; P<0.001) and arteriovenous fistula blood flow (Δblood flow =85 ml/min; 95% CI, 19 to 150 ml/min; P=0.01) and a lower risk of clinical arteriovenous fistula nonmaturation (odds ratio, 0.71; 95% CI, 0.51 to 0.99; P=0.04), all per 10% absolute difference in medial fibrosis. In contrast, venous medial fibrosis was not associated with the postoperative arteriovenous fistula diameter, blood flow, or clinical maturation.

CONCLUSIONS

Preoperative arterial medial fibrosis was associated with greater arteriovenous fistula diameter and blood flow and a lower risk of clinical arteriovenous fistula nonmaturation. This unexpected observation suggests that medial fibrosis promotes arteriovenous fistula development by yet undefined mechanisms or alternatively, that a third factor promotes both medial fibrosis and arteriovenous fistula maturation.

Outcomes of arteriovenous fistulas and grafts with or without intervention before successful use

OBJECTIVE

Arteriovenous fistulas (AVFs) are considered superior to arteriovenous grafts (AVGs) because of longer secondary patency after successful cannulation for dialysis. We evaluated whether access interventions before successful cannulation affect the relative longevity of AVFs and AVGs after successful use.

METHODS

This retrospective study of a prospective database identified patients who initiated dialysis with a catheter and subsequently had a permanent access (289 AVFs and 310 AVGs) placed between January 1, 2006, and December 31, 2011, and were successfully cannulated for dialysis at a large medical center. Patients were monitored until June 30, 2014, and we evaluated the clinical outcomes (secondary patency and frequency of interventions) of the vascular accesses.

RESULTS

An intervention before successful cannulation was required more frequently with AVFs than with AVGs (50.5% vs 17.7%; odds ratio, 4.74; 95% confidence interval [CI], 3.26-6.86; P < .0001). Compared with AVFs that matured without interventions, those that required intervention had shorter secondary patency after successful cannulation (hazard ratio, 1.84; 95% CI, 1.30-2.60; P < .0001) and required more interventions per year after successful use (rate ratio [RR], 1.81; 95% CI, 1.49-2.20; P < .0001). Similarly, AVGs that required intervention before successful cannulation had shorter secondary patency than those without prior intervention (odds ratio, 1.98; 95% CI, 1.52-4.02; P < .0001) and required more interventions per year after successful use (RR, 1.49; 95% CI, 1.27-1.74; P < .0001). AVFs requiring intervention before maturation had inferior secondary patency compared with AVGs that were cannulated without prior intervention (hazard ratio, 1.45; 95% CI, 1.08-2.01; P = .01), but required fewer annual interventions after successful use (RR, 0.57; 95% CI, 0.49-0.66; P < .0001).

CONCLUSIONS

The patency advantage of AVFs over AVGs is no longer evident in patients requiring an AVF intervention before successful cannulation, but the AVFs require fewer interventions after successful use.

Arteriovenous Fistula Development in the First 6 Weeks after Creation

PURPOSE

To assess the anatomic development of native arteriovenous fistula (AVF) during the first 6 weeks after creation by using ultrasonographic (US) measurements in a multicenter hemodialysis fistula maturation study.

MATERIALS AND METHODS

Each institutional review board approved the prospective study protocol, and written informed consent was obtained. Six hundred and two participants (180 women and 422 men, 459 with upper-arm AVF and 143 with forearm AVF) from seven clinical centers underwent preoperative artery and vein US mapping. AVF draining vein diameter and blood flow rate were assessed postoperatively after 1 day, 2 weeks, and 6 weeks. Relationships among US measurements were summarized after using multiple imputation for missing measurements.

RESULTS

In 55% of forearm AVFs (68 of 124) and 83% of upper-arm AVFs (341 of 411) in surviving patients without thrombosis or AVF intervention prior to 6 weeks, at least 50% of their 6-week blood flow rate measurement was achieved at 1 day. Among surviving patients without thrombosis or AVF intervention prior to week 2, 70% with upper-arm AVFs (302 of 433) and 77% with forearm AVFs (99 of 128) maintained at least 85% of their week 2 flow rate at week 6. Mean AVF diameters of at least 0.40 cm were seen in 85% (389 of 459), 91% (419 of 459), and 87% (401 of 459) of upper-arm AVFs and in 40% (58 of 143), 73% (104 of 143), and 77% (110 of 143) of forearm AVFs at 1 day, 2 weeks, and 6 weeks, respectively. One-day and 2-week AVF flow rates and diameters were used to predict 6-week levels, with 2-week prediction of 6-week measures more accurate than those of 1 day (flow rates, R(2) = 0.47 and 0.61, respectively; diameters, R(2) = 0.49 and 0.82, respectively).

CONCLUSION

AVF blood flow rate at 1 day is usually more than 50% of the 6-week blood flow rate. Two-week measurements are more predictive of 6-week diameter and blood flow than those of 1 day. US measurements at 2 weeks may be of value in the early identification of fistulas that are unlikely to develop optimally.

First Report on the OPTN National Variance: Allocation of A2 /A2 B Deceased Donor Kidneys to Blood Group B Increases Minority Transplantation

In 2002, the Organ Procurement and Transplantation Network (OPTN) Minority Affairs Committee (MAC) implemented a national, prospective, "variance of practice" to allow deceased donor, ABO blood group incompatible, A2 antigen, kidney transplantation into blood group B recipients; outcomes of this cohort were compared to ABO compatible recipients. The goal of the variance was to increase the number of transplants to B candidates without negatively impacting survival or compromising system equity. Only B recipients with low anti-A IgG titers (<1:8) were eligible to receive these kidneys. Across eight participating Donation Service Areas (DSA), there were 101 A2 /A2 B to B transplants through 12/31/11, of which the majority of the recipients (61%) were ethnic minorities. At 12, 24, and 36 months, Kaplan-Meier graft survival rates for the B recipients of A2 /A2 B kidneys were 95.0%, 90.6%, and 85.4%, respectively, comparable to outcomes for B recipients of B kidneys, 92.6%, 87.9%, and 82.5%, respectively (p-value = 0.48). Five DSAs increased the proportion of B transplants during 41 months postvariance, with a lesser proportional decrease in blood group A transplants. The data support the proposition that this allocation algorithm may provide a robust mechanism to increase access of blood group B minority candidates to kidney transplantation.

Risk Evaluation of Immediate Surgical Failure During Thigh Hemodialysis Graft Placement by Sonographic Screening

OBJECTIVES

The purpose of this study was to determine whether preoperative sonographic evaluation of vascular diameters and calcification identifies patients at risk for immediate technical failure of thigh hemodialysis grafts.

METHODS

A retrospective analysis of 143 chronic hemodialysis patients who underwent thigh graft placement was performed. All patients underwent preoperative sonography to assess arterial and venous waveforms and vascular diameters. The degree of arterial calcification was assessed retrospectively. Patient characteristics and graft outcomes were examined. Statistical analyses were performed, with P< .05 considered clinically significant.

RESULTS

Sonography identified no or mild arterial calcification in 113 of 143 patients (79%) and moderate to severe calcification in 30 of 143 patients (21%). Primary surgical technical failure occurred in 23% of patients (7 of 30) with moderate to severe calcification, compared to 3.5% (4 of 113) of those with no or mild calcification (hazard ratio, 6.59; 95% confidence interval, 2.06-21.05; P = .002). Cumulative graft survival (time to permanent failure) was shorter in patients with moderate to severe arterial calcification (3-year graft survival, 37% versus 56%; hazard ratio, 2.32; 95% confidence interval, 1.48-6.69; P= .003) but was not significantly associated with venous (P= .82) or arterial (P = .43) diameters.

CONCLUSIONS

Preoperative sonographic assessment of thigh vessel diameters and calcification can identify patients who may be at risk for immediate technical graft failure and decreased cumulative graft survival. The use of sonography as a screening examination may improve preoperative assessment and surgical planning of hemodialysis thigh grafts.

Preoperative arterial microcalcification and clinical outcomes of arteriovenous fistulas for hemodialysis

BACKGROUND

Arteriovenous fistulas (AVFs) often fail to mature, but the mechanism of AVF nonmaturation is poorly understood. Arterial microcalcification is common in patients with chronic kidney disease (CKD) and may limit vascular dilatation, thereby contributing to early postoperative juxta-anastomotic AVF stenosis and impaired AVF maturation. This study evaluated whether preexisting arterial microcalcification adversely affects AVF outcomes.

STUDY DESIGN

Prospective study.

SETTING & PARTICIPANTS

127 patients with CKD undergoing AVF surgery at a large academic medical center.

PREDICTORS

Preexisting arterial microcalcification (≥1% of media area) assessed independently by von Kossa stains of arterial specimens obtained during AVF surgery and by preoperative ultrasound.

OUTCOMES

Juxta-anastomotic AVF stenosis (ascertained by ultrasound obtained 4-6 weeks postoperatively), AVF nonmaturation (inability to cannulate with 2 needles with dialysis blood flow ≥ 300mL/min for ≥6 sessions in 1 month within 6 months of AVF creation), and duration of primary unassisted AVF survival after successful use (time to first intervention).

RESULTS

Arterial microcalcification was present by histologic evaluation in 40% of patients undergoing AVF surgery. The frequency of a postoperative juxta-anastomotic AVF stenosis was similar in patients with or without preexisting arterial microcalcification (32% vs 42%; OR, 0.65; 95% CI, 0.28-1.52; P=0.3). AVF nonmaturation was observed in 29%, 33%, 33%, and 33% of patients with <1%, 1% to 4.9%, 5% to 9.9%, and ≥10% arterial microcalcification, respectively (P=0.9). Sonographic arterial microcalcification was found in 39% of patients and was associated with histologic calcification (P=0.001), but did not predict AVF nonmaturation. Finally, among AVFs that matured, unassisted AVF maturation (time to first intervention) was similar for patients with and without preexisting arterial microcalcification (HR, 0.64; 95% CI, 0.35-1.21; P=0.2).

LIMITATIONS

Single-center study.

CONCLUSIONS

Arterial microcalcification is common in patients with advanced CKD, but does not explain postoperative AVF stenosis, AVF nonmaturation, or AVF failure after successful cannulation.

Pouch adenomas in Familial Adenomatous Polyposis after restorative proctocolectomy

INTRODUCTION

Australian Clinical Practice Guidelines suggest six to twelve-monthly endoscopic pouch surveillance in patients after restorative proctocolectomy for Familial Adenomatous Polyposis (FAP). There are several reports of adenomas and carcinomas forming within the ileum, ileal pouch mucosa or residual rectal mucosa. A retrospective clinical study was performed to audit pouch endoscopic surveillance at a large Sydney tertiary referral Hospital. The aim was to evaluate adenoma development after restorative proctocolectomy for FAP and the adherence rate to published clinical guidelines.

METHODS

Thirty-nine patients who had restorative proctocolectomy for FAP from 1985 to 2011 were identified. Demographic data, details of surgery, original histopathology and details of follow-up pouch endoscopy and pathology findings were obtained.

RESULTS

Of the thirty-nine patients, twenty-seven patients were included in this study. Adenomas were found in twelve of 27 (44%) patients. Mean time to first polyp formation was 88 months and median time was 72 months (range 18-249 months). All polyps were either tubular or tubulovillous in histology. One polyp had high grade dysplasia. The remainder had mild or moderate dysplasia. Polyps were excised either endo-anally or during pouchoscopy. None of the five patients who had a hand-sewn ileal pouch-anal anastomosis (IPAA) developed polyps on follow-up, compared with 12 of the 22 (55%) with a double stapled anastomosis (fishers exact test; p=0.047 (two-tailed)). Of those who developed pouch adenomas, eight (67%) developed further pouch adenomas on follow-up.

CONCLUSIONS

This study supports guidelines recommending lifelong pouch surveillance after restorative proctocolectomy for FAP. Those who develop pouch adenomas may be at greater risk of developing further adenomas. Residual rectal mucosa at the pouch-anal anastomosis should be carefully examined.

A historical comparison of single incision and conventional multiport laparoscopic right hemicolectomy

AIM

Single incision laparoscopic surgery (SILS) is specially suited for surgery of the right colon. This study presents the results of a historical controlled trial comparing single incision and multiport laparoscopic surgery (MLS) for right hemicolectomy.

METHOD

A review of outcome data from 149 patients who underwent laparoscopic right hemicolectomy was performed from the Concord Hospital laparoscopic colorectal database.

RESULTS

Between July 2006 and December 2011, 149 consecutive laparoscopic right hemicolectomies were performed. The first 74 were performed by MLS and from February 2009 all cases were performed by SILS (n = 75).The median ages in the MLS and SILS groups were 74 and 68 years. The median body mass index was 27 kg/m(2) in both groups. Patients were hospitalized for a median of 8 days in the MLS group compared with 5 days in the SILS group. The median length of the extraction wound was 50 mm in the MLS group compared with 43 mm in the SILS group. The indications for surgery were similar in both groups, being 67% and 68%. One patient in each group required conversion to open laparotomy, and no patient in the SILS group required conversion to a conventional multiport technique. Postoperative morbidity was similar in both groups.

CONCLUSION

SILS offers a safe minimally invasive approach to right colon resection. In our series SILS patients had a shorter extraction wound size and shorter length of stay in hospital.

The extent of inflammation is a predictor for pouch-related complications in ileal pouches in patients with ulcerative or indeterminate colitis

AIM

Limited data are available on the relationship between the histological features of the resected specimens in patients with ulcerative colitis (UC) or indeterminate colitis (IC) and the outcome of restorative proctocolectomy. The aim of our study was to determine if the histological features of the resected specimen in patients with UC and IC can predict ileal-pouch-related outcome.

METHOD

A review of all patients who had a restorative proctocolectomy created following completion proctectomy or proctocolectomy for UC and IC was performed.

RESULTS

Between 1992 and 2011, 142 patients (132 with UC and 10 with IC) were reviewed. After a median follow-up of 36 (3-149) months, 51 (35.9%) developed a pouch-related complication. Forty-two (29.7%) developed pouchitis while three (2.1%) developed a pouch-cutaneous fistula. Four (2.8%) had pouch failure, while stricture of the anastomosis was seen in three (2.1%) patients. The presence of extension of the inflammation into the muscularis propria of the resected specimen was associated with an increased risk of pouch-related complications (P = 0.01). The presence of submucosal oedema was also a significant risk factor (P = 0.03).

CONCLUSION

The extension of inflammation into the muscularis propria appears to predict pouch-related complications following restorative proctocolectomy for UC or IC.

Definitive surgical closure of enterocutaneous fistula: outcome and factors predictive of increased postoperative morbidity

AIM

Enterocutaneous fistula (ECF) presents a complex management problem with significant mortality and morbidity. The aim of this study was to assess the outcome of patients undergoing surgical cure for ECF and to predict factors that might relate to increased postoperative morbidity.

METHOD

Medical records of all patients who underwent definitive surgery for cure of an ECF within our colorectal surgery unit between 2000 and 2010 were reviewed.

RESULTS

Forty-one patients (18 male) were identified, in whom 44 definitive procedures were performed. The median age was 54 (17-81) years. The median postoperative length of stay in hospital was 14 (2-213) days. Half (50%) of the ECFs occurred as a postoperative complication followed by spontaneous fistulation in Crohn's disease (36%). The interval to definitive surgery was influenced by the aetiology of the fistula. The median time to surgery after formation of postoperative fistula was 240 days (7.9 months). There was no 30-day postoperative mortality. There were two (4.5%) recurrences at 3 months. Thirty-eight (86%) patients suffered postoperative morbidity as defined by the Clavien-Dindo classification. High-grade morbidity occurred in 32% of patients. On univariate analysis, factors identified as being significantly associated with high-grade morbidity included a fistula output of > 500 ml/day (P = 0.004) in patients with postoperative ECF, malnutrition at presentation (P = 0.04) and a serum albumin value of < 30 g/l (P = 0.02) in patients with spontaneous ECF due to Crohn's disease.

CONCLUSION

The majority of persistent complex ECFs can be cured surgically with low mortality and recurrence in a multidisciplinary setting. Postoperative morbidity, however, remains a significant burden.

Decision-making in rectal surgery

AIM

The decision to create a stoma after anterior resection has significant consequences. Decisions under uncertainty are made with a variety of cognitive tools, or heuristics. Past experience has been shown to be a powerful heuristic in other domains. Our aim was to identify whether the misfortune of recent anastomotic leakage or surgeon propensity to take everyday risks would affect their decision to defunction a range of anastomoses.

METHOD

Questionnaires were sent to members of the Colorectal Surgical Society of Australia and New Zealand. Participants were asked for demographic information, questions regarding risk-taking propensity, when their last anastomotic leakage occurred and whether they would defunction a range of hypothetical rectal anastomoses grouped according to height, American Society of Anesthesiologists grade and use of preoperative radiotherapy. Scores were derived for hypothetical patient likelihood of having a stoma created and individual surgeon propensity for stoma formation. Hazard regression analysis was used to assess demographic predictors of stoma formation.

RESULTS

In total, 110 (75.3%) of 146 surveyed surgeons replied; 72 (65.5%) reported anastomotic leakage within the last 12 months. Surgeons' propensity for risk-taking was comparable (24.6 vs 27.53, 95% confidence interval, Mann-Whitney-U) to previously studied participants in economic models. Surgeon age (< 50 years) and lower propensity for risk-taking were demonstrated to be independent predictors of stoma formation on regression analysis.

CONCLUSION

Although the decision to create a stoma after anterior resection may be made in the belief that its foundation derives from rational thought, it appears that other unrecognized operator factors such as age and risk-taking exert an effect.

Long-term outcome of the anal fistula plug for anal fistula of cryptoglandular origin

AIM

This study aimed to evaluate the long-term outcome of the anal fistula plug in the treatment of anal fistula of cryptoglandular origin.

METHOD

A review of all patients who had at least one anal fistula plug inserted from March 2007 to August 2008 was performed. Only anal fistulae of cryptoglandular origin were included. Success was defined as the closure of the external opening with no further purulent discharge or collection.

RESULTS

Thirty anal fistula plugs were inserted in 26 patients [median age 40 (26-70) years]. Twenty-six of the fistulae were transsphincteric and three were suprasphincteric. One patient had a high intersphincteric fistula, which was the only fistula that did not have a seton inserted. The median duration between seton insertion and the plug procedure was 12 (4-28) weeks. The median length of the fistula tract was 3 (1-7.5) cm. After a median follow-up of 59 (13-97) weeks, 26 (86.7%) fistulae recurred. Of the 26 failures, the median time to failure was 8 (2-54) weeks. Subsequent surgical interventions were performed in 20 of the failures.

CONCLUSION

The role of the fistula plug in the management of anal fistula of cryptoglandular origin remains debatable and warrants further evaluation.

Preoperative venous intimal hyperplasia, postoperative arteriovenous fistula stenosis, and clinical fistula outcomes

BACKGROUND AND OBJECTIVES

Arteriovenous fistulas often fail to mature, and nonmaturation has been attributed to postoperative stenosis caused by aggressive neointimal hyperplasia. Preexisting intimal hyperplasia in the native veins of uremic patients may predispose to postoperative arteriovenous fistula stenosis and arteriovenous fistula nonmaturation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This work explored the relationship between preexisting venous intimal hyperplasia, postoperative arteriovenous fistula stenosis, and clinical arteriovenous fistula outcomes in 145 patients. Venous specimens obtained during arteriovenous fistula creation were quantified for maximal intimal thickness (median thickness=22.3 μm). Postoperative ultrasounds at 4-6 weeks were evaluated for arteriovenous fistula stenosis. Arteriovenous fistula maturation within 6 months of creation was determined clinically.

RESULTS

Postoperative arteriovenous fistula stenosis was equally frequent in patients with preexisting venous intimal hyperplasia (thickness>22.3 μm) and patients without hyperplasia (46% versus 53%; P=0.49). Arteriovenous fistula nonmaturation occurred in 30% of patients with postoperative stenosis versus 7% of those patients without stenosis (hazard ratio, 4.33; 95% confidence interval, 1.55 to 12.06; P=0.001). The annual frequency of interventions to maintain arteriovenous fistula patency for dialysis after maturation was higher in patients with postoperative stenosis than patients without stenosis (0.83 [95% confidence interval, 0.58 to 1.14] versus 0.42 [95% confidence interval, 0.28 to 0.62]; P=0.008).

CONCLUSIONS

Preexisting venous intimal hyperplasia does not predispose to postoperative arteriovenous fistula stenosis. Postoperative arteriovenous fistula stenosis is associated with a higher arteriovenous fistula nonmaturation rate. Arteriovenous fistulas with hemodynamically significant stenosis frequently mature without an intervention. Postoperative arteriovenous fistula stenosis is associated with an increased frequency of interventions to maintain long-term arteriovenous fistula patency after maturation.

Correlation of pre-existing vascular pathology with arteriovenous graft outcomes in hemodialysis patients

BACKGROUND

Arteriovenous grafts (AVGs) are prone to neointimal hyperplasia leading to AVG failure. We hypothesized that pre-existing pathologic abnormalities of the vessels used to create AVGs (including venous intimal hyperplasia, arterial intimal hyperplasia, arterial medial fibrosis, and arterial calcification) are associated with inferior AVG survival.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

Patients with chronic kidney disease undergoing placement of a new AVG at a large medical center who had vascular specimens obtained at the time of surgery (n = 76).

PREDICTOR

Maximal intimal thickness of the arterial and venous intima, arterial medial fibrosis, and arterial medial calcification.

OUTCOME & MEASUREMENTS

Unassisted primary AVG survival (time to first intervention) and frequency of AVG interventions.

RESULTS

55 patients (72%) underwent interventions and 148 graft interventions occurred during 89.9 years of follow-up (1.65 interventions per graft-year). Unassisted primary AVG survival was not associated significantly with arterial intimal thickness (HR, 0.72; 95% CI, 0.40-1.27; P = 0.3), venous intimal thickness (HR, 0.64; 95% CI, 0.37-1.10; P = 0.1), severe arterial medial fibrosis (HR, 0.58; 95% CI, 0.32-1.06; P = 0.6), or severe arterial calcification (HR, 0.68; 95% CI, 0.37-1.31; P = 0.3). The frequency of AVG interventions per year was associated inversely with arterial intimal thickness (relative risk [RR], 1.99; 95% CI, 1.16-3.42; P < 0.001 for thickness <10 vs. >25 μm), venous intimal thickness (RR, 2.11; 95% CI, 1.39-3.20; P < 0.001 for thickness <5 vs. >10 μm), arterial medial fibrosis (RR, 3.17; 95% CI, 1.96-5.13; P < 0.001 for fibrosis <70% vs. ≥70%), and arterial calcification (RR, 2.12; 95% CI, 1.31-3.43; P = 0.001 for <10% vs. ≥10% calcification).

LIMITATIONS

Single-center study. Study may be underpowered to demonstrate differences in unassisted primary AVG survival.

CONCLUSIONS

Pre-existing vascular pathologic abnormalities in patients with chronic kidney disease may not be associated significantly with unassisted primary AVG survival. However, vascular intimal hyperplasia, arterial medial fibrosis, and arterial calcification may be associated with a decreased frequency of AVG interventions.

Observation of associated near-side and away-side long-range correlations in sqrt[s(NN)]=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δø) and pseudorapidity (Δη) are measured in sqrt[s(NN)] = 5.02 TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1 μb(-1) of data as a function of transverse momentum (p(T)) and the transverse energy (ΣE(T)(Pb)) summed over 3.1 < η < 4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2 < |Δ η | < 5) "near-side" (Δø ~ 0) correlation that grows rapidly with increasing ΣE(T)(Pb). A long-range "away-side" (Δø ~ π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣE(T)(Pb), is found to match the near-side correlation in magnitude, shape (in Δη and Δø) and ΣE(T)(Pb) dependence. The resultant Δø correlation is approximately symmetric about π/2, and is consistent with a dominant cos2Δø modulation for all ΣE(T)(Pb) ranges and particle p(T).

Measurement of Z boson production in Pb-Pb collisions at sqrt[s(NN)]=2.76 TeV with the ATLAS detector

The ATLAS experiment has observed 1995 Z boson candidates in data corresponding to 0.15  nb(-1) of integrated luminosity obtained in the 2011 LHC Pb+Pb run at sqrt[s(NN)]=2.76  TeV. The Z bosons are reconstructed via dielectron and dimuon decay channels, with a background contamination of less than 3%. Results from the two channels are consistent and are combined. Within the statistical and systematic uncertainties, the per-event Z boson yield is proportional to the number of binary collisions estimated by the Glauber model. The elliptic anisotropy of the azimuthal distribution of the Z boson with respect to the event plane is found to be consistent with zero.

Search for dark matter candidates and large extra dimensions in events with a photon and missing transverse momentum in pp collision data at sqrt[s]=7 TeV with the ATLAS detector

Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum in proton-proton collisions at sqrt[s] = 7 TeV are reported. Data collected by the ATLAS experiment at the LHC corresponding to an integrated luminosity of 4.6 fb(-1) are used. Good agreement is observed between the data and the standard model predictions. The results are translated into exclusion limits on models with large extra spatial dimensions and on pair production of weakly interacting dark matter candidates.

Search for magnetic monopoles in sqrt[s]=7 TeV pp collisions with the ATLAS detector

This Letter presents a search for magnetic monopoles with the ATLAS detector at the CERN Large Hadron Collider using an integrated luminosity of 2.0  fb(-1) of pp collisions recorded at a center-of-mass energy of sqrt[s]=7  TeV. No event is found in the signal region, leading to an upper limit on the production cross section at 95% confidence level of 1.6/ϵ  fb for Dirac magnetic monopoles with the minimum unit magnetic charge and with mass between 200 GeV and 1500 GeV, where ϵ is the monopole reconstruction efficiency. The efficiency ϵ is high and uniform in the fiducial region given by pseudorapidity |η|<1.37 and transverse kinetic energy 600-700<E(kin)sinθ<1400  GeV. The minimum value of 700 GeV is for monopoles of mass 200 GeV, whereas the minimum value of 600 GeV is applicable for higher mass monopoles. Therefore, the upper limit on the production cross section at 95% confidence level is 2 fb in this fiducial region. Assuming the kinematic distributions from Drell-Yan pair production of spin-1/2 Dirac magnetic monopoles, the efficiency is in the range 1%-10%, leading to an upper limit on the cross section at 95% confidence level that varies from 145 fb to 16 fb for monopoles with mass between 200 GeV and 1200 GeV. This limit is weaker than the fiducial limit because most of these monopoles lie outside the fiducial region.

Search for direct top squark pair production in final states with one isolated lepton, jets, and missing transverse momentum in sqrt[s] = 7 TeV pp collisions using 4.7 fb(-10 of ATLAS data

A search is presented for direct top squark pair production in final states with one isolated electron or muon, jets, and missing transverse momentum in proton-proton collisions at sqrt[s] = 7 TeV. The measurement is based on 4.7 fb(-1) of data collected with the ATLAS detector at the LHC. Each top squark is assumed to decay to a top quark and the lightest supersymmetric particle (LSP). The data are found to be consistent with standard model expectations. Top squark masses between 230 GeV and 440 GeV are excluded with 95% confidence for massless LSPs, and top squark masses around 400 GeV are excluded for LSP masses up to 125 GeV.

Search for a supersymmetric partner to the top quark in final states with jets and missing transverse momentum at sqrt[s] = 7 TeV with the ATLAS detector

A search for direct pair production of supersymmetric top squarks (t(1)) is presented, assuming the t(1) decays into a top quark and the lightest supersymmetric particle, χ(1)(0), and that both top quarks decay to purely hadronic final states. A total of 16 (4) events are observed compared to a predicted standard model background of 13.5(-3.6)(+3.7)(4.4(-1.3)(+1.7)) events in two signal regions based on ∫Ldt = 4.7 fb(-1) of pp collision data taken at sqrt[s] = 7 TeV with the ATLAS detector at the LHC. An exclusion region in the t(1) versus χ(1)(0) mass plane is evaluated: 370<m(t)(1)}<465 GeV is excluded for m(χ)(1)(0) ~ 0 GeV while m(t)(1) = 445 GeV is excluded for m(χ)(1)(0) ≤ 50 GeV.

Search for supersymmetry in events with three leptons and missing transverse momentum in √[s]=7 TeV pp collisions with the ATLAS detector

A search for the weak production of charginos and neutralinos decaying to a final state with three leptons (electrons or muons) and missing transverse momentum is presented. The analysis uses 2.06 fb(-1) of √[s]=7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with standard model expectations in two signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric and simplified models. For the simplified models, degenerate lightest chargino and next-to-lightest neutralino masses up to 300 GeV are excluded for mass differences from the lightest neutralino up to 300 GeV.

Stenting large bowel obstruction avoids a stoma: consecutive series of 100 patients

AIM

Large bowel obstruction (LBO) is a surgical emergency that requires urgent operative intervention and often a stoma. The introduction of a self-expanding metallic stent provides an alternative for this group of patients. The aim of this study was to assess prospectively the results in the first 100 consecutive patients with LBO undergoing attempted self-expanding metallic stent insertion at the Royal Prince Alfred Hospital, Sydney, Australia.

METHOD

A prospective consecutive uncontrolled trial of 100 patients having an attempted self-expanding metallic stent insertion for LBO was performed after institutional ethical approval.

RESULTS

The mean age was 63.9 years (range 16-95). Primary colorectal cancer was the most common cause of LBO (61%). A self-expanding metallic stent was inserted with a palliative intent in 89% of patients. An initial technical success rate of 87% was achieved. Overall 30-day mortality was 7% (95% CI, 3.4-13.7%), with only one stent-related death within 30 days of stent insertion. Morbidity occurred in 20% of patients. Surgery was avoided in 69 patients and permanent stoma was avoided in 72 patients. The median follow up was 34.5 months (range 1-64 months).

CONCLUSION

In this uncontrolled study, self-expanding metallic stents had a low morbidity and a low procedure-related mortality. A randomized controlled trial has commenced in our institution, in which length of stay, quality of life, morbidity and mortality of patients with stents are compared with those of patients having open procedures during palliative care for LBO.

Medial fibrosis, vascular calcification, intimal hyperplasia, and arteriovenous fistula maturation

BACKGROUND

Arteriovenous fistulas (AVFs) for hemodialysis frequently fail to mature because of inadequate dilation or early stenosis. The pathogenesis of AVF nonmaturation may be related to pre-existing vascular pathologic states: medial fibrosis or microcalcification may limit arterial dilation, and intimal hyperplasia may cause stenosis.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

Patients with chronic kidney disease (N = 50) undergoing AVF placement.

PREDICTORS

Medial fibrosis, microcalcification, and intimal hyperplasia in arteries and veins obtained during AVF creation.

OUTCOME & MEASUREMENTS

AVF nonmaturation.

RESULTS

AVF nonmaturation occurred in 38% of patients despite attempted salvage procedures. Preoperative arterial diameter was associated with upper-arm AVF maturation (P = 0.007). Medial fibrosis was similar in patients with nonmaturing and mature AVFs (60% ± 14% vs 66% ± 13%; P = 0.2). AVF nonmaturation was not associated with patient age or diabetes, although both variables were associated significantly with severe medial fibrosis. Conversely, AVF nonmaturation was higher in women than men despite similar medial fibrosis in both sexes. Arterial microcalcification (assessed semiquantitatively) tended to be associated with AVF nonmaturation (1.3 ± 0.8 vs 0.9 ± 0.8; P = 0.08). None of the arteries or veins obtained at AVF creation had intimal hyperplasia. However, repeated venous samples obtained in 6 patients during surgical revision of an immature AVF showed venous neointimal hyperplasia.

LIMITATIONS

Single-center study.

CONCLUSION

Medial fibrosis and microcalcification are frequent in arteries used to create AVFs, but do not explain AVF nonmaturation. Unlike previous studies, intimal hyperplasia was not present at baseline, but developed de novo in nonmaturing AVFs.

Ethnic and gender related differences in the risk of end-stage renal disease after living kidney donation

There is limited data pertaining to the risk of End Stage Renal Disease (ESRD) after living kidney donation. The Organ Procurement and Transplantation Network and the Center for Medicare and Medicaid Services databases were used to identify living kidney donors (LKDs) who subsequently developed ESRD and to calculate LKD ESRD rates. We found 126 cases of ESRD among 56 458 LKDs (0.22%) who donated during October 1, 1987-March 31, 2003. The overall LKD ESRD rate was 0.134 per 1000 years at risk, with an average duration of follow-up of 9.8 years. ESRD rates for LKDs overall and for Black, White, male and female donors compared favorably to the ESRD incidence in the general population. The LKD ESRD rate was nearly five times higher for Blacks than for Whites and two times higher for males than females. However, these ethnic and gender-related differences were similar to those previously reported for ESRD in the general population. Our findings do not show an increase in the risk of ESRD for LKDs and support the current practice of living kidney donation. Further research is needed to determine if improved donor screening or follow-up will reduce the risk of postdonation ESRD.

Ethnic and gender related differences in the risk of end-stage renal disease after living kidney donation

There is limited data pertaining to the risk of End Stage Renal Disease (ESRD) after living kidney donation. The Organ Procurement and Transplantation Network and the Center for Medicare and Medicaid Services databases were used to identify living kidney donors (LKDs) who subsequently developed ESRD and to calculate LKD ESRD rates. We found 126 cases of ESRD among 56 458 LKDs (0.22%) who donated during October 1, 1987-March 31, 2003. The overall LKD ESRD rate was 0.134 per 1000 years at risk, with an average duration of follow-up of 9.8 years. ESRD rates for LKDs overall and for Black, White, male and female donors compared favorably to the ESRD incidence in the general population. The LKD ESRD rate was nearly five times higher for Blacks than for Whites and two times higher for males than females. However, these ethnic and gender-related differences were similar to those previously reported for ESRD in the general population. Our findings do not show an increase in the risk of ESRD for LKDs and support the current practice of living kidney donation. Further research is needed to determine if improved donor screening or follow-up will reduce the risk of postdonation ESRD.

Ethnic and gender related differences in the risk of end-stage renal disease after living kidney donation

There is limited data pertaining to the risk of End Stage Renal Disease (ESRD) after living kidney donation. The Organ Procurement and Transplantation Network and the Center for Medicare and Medicaid Services databases were used to identify living kidney donors (LKDs) who subsequently developed ESRD and to calculate LKD ESRD rates. We found 126 cases of ESRD among 56 458 LKDs (0.22%) who donated during October 1, 1987-March 31, 2003. The overall LKD ESRD rate was 0.134 per 1000 years at risk, with an average duration of follow-up of 9.8 years. ESRD rates for LKDs overall and for Black, White, male and female donors compared favorably to the ESRD incidence in the general population. The LKD ESRD rate was nearly five times higher for Blacks than for Whites and two times higher for males than females. However, these ethnic and gender-related differences were similar to those previously reported for ESRD in the general population. Our findings do not show an increase in the risk of ESRD for LKDs and support the current practice of living kidney donation. Further research is needed to determine if improved donor screening or follow-up will reduce the risk of postdonation ESRD.