Incidence of and risk factors for bowel ischemia after abdominal aortic aneurysm repair

Changes in the Remaining Iliac Artery According to Retrograde Flow after Aorto-Femoral Bypass in Abdominal Aortic Aneurysms

BACKGROUND

Considering a patient's anatomy and vascular conditions, aorto-femoral bypass is a treatment approach for the open repair of abdominal aortic aneurysms. This study aimed at evaluating changes in the remnant iliac artery and their correlation with the preservation state of retrograde flow from femoral anastomosis.

METHODS

Of 221 patients who underwent abdominal aortic aneurysm surgery between 2007 and 2022 in Pusan National University Hospital, 29 patients who underwent aorto-femoral bypass were included in this retrospective cohort study. Of these patients, 21 underwent aortobifemoral bypass and 8 underwent aortoiliac-and-femoral bypass. The change in size of the iliac artery from preoperative to postoperative and whether this difference in size depended on the status of postoperative retrograde flow were investigated. Additionally, factors affecting overall mortality and ischemic complications were identified.

RESULTS

The median duration from operation to the last follow-up was 2069.5 days (about 5.7 years). The average age of the patients was 78.1 years, and the proportion of males was 75.9%. In cases of disappearance of postoperative retrograde flow from the femoral anastomosis, the postoperative iliac artery size was significantly reduced compared to its preoperative size (18.4 ± 18.9 mm vs. 13.2 ± 7.9 mm, respectively; P = 0.04). The group with maintained retrograde flow had significantly larger residual common iliac artery size than the group with disappearance of flow. (20.0 ± 28.0 mm vs. 14.6 ± 8.5 mm, respectively; P = 0.02). Disappearance of retrograde flow was a significant factor in the iliac artery size reduction after surgery (odds ratio, 2.5; 95% confidence interval, 1.9-5.3; P = 0.02). Three patients with maintained retrograde flow (18.8%) required intervention owing to an increase in the size of the iliac artery. The factors that significantly influenced overall death as analyzed by Cox proportional hazard regression were chronic obstructive pulmonary disease (hazard ratio, 36.8; 95% confidence interval, 1.6-870.0; P = 0.03), peripheral arterial occlusive disease (hazard ratio, 12.7; 95% confidence interval, 1.4-115.8; P = 0.02), and disappearance of retrograde flow (hazard ratio, 8.7; 95% confidence interval, 1.2-63.9; P = 0.03).

CONCLUSIONS

Among the open repair methods for abdominal aortic aneurysms, if retrograde flow was not maintained through femoral anastomosis when aorto-femoral bypass was performed, the size of the remaining iliac artery decreased. However, loss of retrograde flow increased long-term mortality. When aorto-femoral bypass is performed, regular imaging follow-up is necessary at appropriate intervals to check the remnant iliac artery and retrograde flow.

Long-term outcomes of TEVAR for thoracic aortic diseases: a retrospective single-center study

BACKGROUND

The outcomes of Thoracic Endovascular Aortic Repair (TEVAR) vary depending on thoracic aortic pathologies, comorbidities. This study presents our comprehensive endovascular experience, focusing on exploring the outcome in long term follow-up.

METHODS

From 2006 to 2018, we conducted TEVAR on 97 patients presenting with various aortic pathologies. This retrospective cohort study was designed primarily to assess graft durability and secondarily to evaluate mortality causes, complications, reinterventions, and the impact of comorbidities on survival using Kaplan-Meier and Cox regression analyses.

RESULTS

The most common indication was thoracic aortic aneurysm (n = 52). Ten patients had aortic arch variations and anomalies, and the bovine arch was observed in eight patients. Endoleaks were the main complications encountered, and 10 of 15 endoleaks were type I endoleaks. There were 18 reinterventions; the most of which was TEVAR (n = 5). The overall mortality was 20 patients, with TEVAR-related causes accounting for 12 of these deaths, including intracranial bleeding in three patients. Multivariant Cox regression revealed chronic renal diseases (OR = 11.73; 95% CI: 2.04-67.2; p = 0.006), previous cardiac operation (OR = 14.26; 95% CI: 1.59-127.36; p = 0.01), and chronic obstructive pulmonary diseases (OR = 7.82; 95% CI: 1.43-42.78; p = 0.001) to be independent risk factors for 10-year survival. There was no significant difference in the survival curves of the various aortic pathologies. In the follow-up period, two non-symptomatic intragraft thromboses and one graft infection were found.

CONCLUSION

Comorbidities can increase the risk of TEVAR-related mortality without significantly impacting endoleak rates. TEVAR is effective for severe aortic pathologies, though long-term graft durability may be compromised by its thrombosis and infection.

Editor's Choice - Prevalence of Smoking and Impact on Peri-Operative Outcomes After Elective Abdominal Aortic Aneurysm Repair

OBJECTIVE

The contemporary burden of smoking in patients undergoing elective abdominal aortic aneurysm (AAA) repair in the UK is unknown. This study aimed to quantify the prevalence of smoking in patients undergoing AAA repair in the UK and determine the association between smoking and peri-operative outcomes.

METHODS

This was an observational cohort study. The National Vascular Registry was interrogated for adults undergoing elective infrarenal AAA repair from 2014 to 2021 for prevalence of current smokers, former smokers, and non-smokers over time. The primary outcomes were post-operative complications by smoking status. Secondary outcomes were variation in smoking rates over time and by hospital, in hospital mortality, and length of stay by smoking status. All analyses were adjusted using the validated British Aneurysm Repair score.

RESULTS

Overall, 26 916 patients undergoing elective AAA repair were included (21.9% smokers, 62.2% former smokers, 15.9% non-smokers). The prevalence of smoking did not change over time, with a 2.4 fold variation between UK hospitals (range 13.0 - 31.8% excluding outliers). In hospital mortality was not significantly different between smokers, former smokers, and non-smokers (p > .050 for all comparisons). Compared with non-smokers, smoking was associated with increased overall (odds ratio [OR] 1.40, 95% confidence interval [CI] 1.24 - 1.57) and respiratory complications (OR 1.98, 95% CI 1.63 - 2.39), limb ischaemia (OR 1.63, 95% CI 1.19 - 2.23), bowel ischaemia (OR 1.64, 95% CI 1.06 - 2.54), return to theatre (OR 1.38, 95% CI 1.11 - 1.71), and intensive care admission (OR 1.43, 95% CI 1.31 - 1.56). Compared with former smokers, smoking was associated with increased overall (OR 1.24, 95% CI 1.14 - 1.36), respiratory (OR 1.44, 95% CI 1.27 - 1.63) and limb ischaemia complications (OR 1.48, 95% CI 1.19 - 1.84), and intensive care admission (OR 1.37, 95% CI 1.28 - 1.46). On analysis of the endovascular aneurysm repair subgroup, active smoking was associated with significantly higher rates of limb ischaemia compared with former and non-smokers (OR 2.12, 95% CI 1.49 - 3.01 and OR 1.94, 95% CI 1.19 - 3.16 respectively).

CONCLUSION

The prevalence of smoking remains high in patients undergoing elective AAA repair with no evidence of a decline in active smokers from 2014 to 2021 compared with the general UK population. Smoking is associated with increased peri-operative complication rates.

Computed Tomography Angiography After Transcatheter and Surgical Aortic Interventions

This comprehensive article reviews the complex realm of aortic surgical and endovascular interventions, focusing on the aortic root, ascending aorta, aortic arch, descending aorta, and abdominal aorta. It outlines the nuances of various procedures, emphasizing the importance of computed tomography angiography acquisition for an accurate assessment. Detailed discussions encompass expected postsurgical/endovascular findings and complications, covering various scenarios, from hematoma and infection to pseudoaneurysms and graft-related issues. This article serves as a crucial resource for radiologists, offering invaluable insights into the complexities of aortic interventions and their subsequent imaging, fostering a comprehensive understanding of diagnostic and management strategies.

Intraoperative calf blood pressure measurements for the detection of early lower extremity ischemia following endovascular aneurysm repair

BACKGROUND

Access vessel complications during endovascular aneurysm repair (EVAR) remain a concern and has been reported to occur in 3-10% of cases. The purpose of this study is to report our experience with intraoperative, non-invasive calf blood pressure (BP) measurements and ankle brachial indexes (ABIs) before and immediately following EVAR, in evaluating the perfusion of the lower extremities and detecting early lower extremity ischemia (LEI).

METHODS

We performed a retrospective review of all consecutive patients who underwent EVAR at our institution between the years 2019 and 2021. All patients had blood pressure cuffs placed on their calves prior to the procedure. Calf BP measurements and ABIs were obtained prior to and immediately after the surgery. Based on the BP measurements, patients were categorized into two groups. Group 1: patients with unchanged ABIs at the end of the procedure. Group 2: patients who experienced a decrease in ABIs at the end of the procedure (no BP obtained or decrease of ABI >0.3 from preoperative measurement). Patients in group 2 underwent exploration of the access vessel. Based on these, the positive and negative predictive values of the study were calculated.

RESULTS

During the study period we performed 113 EVAR procedures for abdominal, thoracic, and thoracoabdominal aortic aneurysms, in which 226 femoral arteries were accessed. Mean age was 71 years and 88% were males. In 219 (97%) of the limbs, there was no change in calf BP measurements and ABIs immediately after the procedure, when compared to the preoperative measurements, and none suffered a decrease in follow up ABIs. In 7 limbs (3%), there was a decrease in the calf BP (group 2), and all underwent exploration of the femoral artery. In 5 of these, a pathology was found within the artery. The positive predictive value of the intraoperative calf BP measurement was 71%. The negative predictive value of the study was 100%.

CONCLUSION

Intraoperative calf BP and ABIs is a simple method to assess the lower limb perfusion and detect LEI following EVAR. The exam is particularly accurate in ruling out LEI as it has a very high negative predictive value. However, an abnormal measurement does not necessarily confirm LEI.

Surgical prevalence and outcomes in ischemic colitis: A systematic review and meta-analysis

BACKGROUND/AIM

This study reviews the literature to examine the proportion of patients requiring surgical management in ischemic colitis (IC) and identify surgical outcomes.

METHOD

A systematic review of PubMed, EMBASE, and Cochrane Central Register of Controlled Trials was conducted in accordance with the latest Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. English language studies and adult patients were included. Studies with fewer than 10 patients, and IC post aortic or cardiac surgery was excluded. We present our systematic review and meta-analysis with pooled proportions of right sided IC distribution and prevalence of surgical treatment.

RESULTS

23 studies with a total of 12,844 patients were included in the systematic review, with 19 studies and 12,420 patients included in the meta-analysis. Four studies were excluded from the meta-analysis due to only including specific cohorts of patients-two with cocaine induced colitis, one with phlebosclerotic colitis, and one with IC associated with acute myocardial infarction. The pooled proportion of right sided IC distribution was 15% (CI 14%-17%, p < 0.001), whilst the pooled proportion of surgical management of IC was 15% (CI 13%-16% p < 0.001).

CONCLUSION

Prevalence of surgical management of IC is rare. Right sided IC is associated with higher mortality and higher rates of surgical management. Reporting of surgical outcomes is scant.

Indocyanin Green Fluorescence Evaluation of Colonic Perfusion During Elective Open Abdominal Aortic Aneurysm Repair

OBJECTIVES

Colonic ischaemia is a rare but devastating complication of open aortic aneurysm repair and is associated with high morbidity and a mortality of up to 50%. The aim of this study was to determine the safety and effectiveness of using indocyanin green florescence (ICG) to interrogate colonic perfusion intra-operatively.

DESIGN

Prospective observational study.

METHODS

All elective open abdominal aneurysm repairs over a 6 month period underwent colonic perfusion interrogation with ICG according to a pre-defined protocol. Patient demographics and imaging findings were recorded prior to surgery. ICG was given just prior to laparotomy closure. Time to florescence was measured from the start of IV administration to surgeon defined maximal florescence of the sigmoid colon.

RESULTS

Ten patients fulfilled the inclusion criteria. All patients were male with an average age of 69.7 years. Inferior mesenteric artery reimplantation was performed in 5 patients. Median colonic fluorescence time was 58 s. No complications related to ICG were identified. A single patient had clinical concern of colonic ischaemia and delayed perfusion (>3 min) on ICG; colorectal opinion advised not for immediate resection. At relook laparotomy, ischaemic colon at the area of demarcation was noted and a Hartmann's procedure was performed. No other patients had delayed perfusion and no further episodes of colonic ischaemia were noted. IMA reimplantation did not show statistical difference in colonic ICG time (P = .81, 95% CI -1.98 to 2.45). There was no statistical difference between operating times between the cohort and all repairs performed 6 months before the data collection (P = .59, 95% CI -.73 to 1.24).

CONCLUSION

In this pilot study ICG appears to be a safe and useful adjunct in objective assessment of colonic perfusion during open AAA repair. Further research is required to fully determine its role in this cohort of patients.

Risk Factors and Early Outcomes for Gastrointestinal Complications in Patients Undergoing Open Surgery for Type A Aortic Dissection

BACKGROUND

Gastrointestinal complications need to be paid more attention, especially in critically ill patients. The purpose of this study was to identify the risk factors and short-term outcomes of gastrointestinal complications after open surgery for type A aortic dissection.

METHODS

A retrospective single-institutional study including patients who underwent open surgery for type A aortic dissection during 2012-2020 was conducted. Univariate analysis and logistic regression analysis were used to identify risk factors associated with gastrointestinal complications. The related clinical outcomes were compared between the patients with and without gastrointestinal complications.

RESULTS

Among the 2746 patients, 150 developed gastrointestinal complications. The development of gastrointestinal complications contributed to the higher rate of mortality (P = .008), longer stay in the intensive care unit (P < .001), and longer hospital stay (P < .001). Logistic regression analysis showed that age (odds ratio [OR] 1.020; 95% confidence interval [CI] 1.005-1.057; P = .011), American Society of Anesthesiologists classification greater than grade III (OR 1.724; 95%CI 1.179-2.521, P = .005), pre-induction mean arterial pressure (OR 0.978; 95%CI 0.965-0.990, P = .001), aortic cross-clamp time (OR 1.012; 95%CI 1.005-1.019, P = .001), cardiopulmonary bypass time (OR 1.007; 95%CI 1.002-1.011, P = .002), and intraoperative transfusion of red blood cells (OR 1.214; 95%CI 1.122-1.314, P = .001) were independent risk factors for gastrointestinal complications.

CONCLUSIONS

The incidence of gastrointestinal complications after open surgery for type A aortic dissection was 5.5%, resulting in increased mortality and prolonged hospital stay. It is necessary to take suitable strategies to reduce the incidence of gastrointestinal complications.

Treatment Outcomes of Patients With Ruptured Abdominal Aortic Aneurysms

BACKGROUND

Ruptured abdominal aortic aneurysm (rAAA) is a serious complication of abdominal aortic aneurysm associated with high operative mortality and morbidity rates. The present study evaluated the perioperative and long-term outcomes of Korean patients with rAAA based on national health insurance claims data.

METHODS

The National Health Insurance Service (NHIS) database was searched retrospectively to identify patients with rAAA who underwent endovascular aneurysm repair (EVAR) and open surgical repair (OSR) from 2009 to 2018. Perioperative (≤ 30 days), early postoperative (≤ 3 month), and long-term (> 3 month) survival, reinterventions, and complications were assessed.

RESULTS

The search identified 1,034 patients with rAAA, including 594 who underwent EVAR and 440 who underwent OSR. When the study period was divided into two, the total numbers of patients with rAAA, patients who underwent EVAR, and octogenarians were higher during the second half. The perioperative mortality rate was 29.8% in the EVAR and 35.0% in the OSR group (P = 0.028). Hartmann's procedure for bowel infarction was performed more frequently in the OSR than in the EVAR group (adjusted odds ratio, 6.28; 95% confidence interval [CI], 2.33-21.84; P = 0.001), but other complication rates did not differ significantly. All-cause mortality during the entire observation period did not differ significantly in the EVAR and OSR groups (adjusted hazard ratio, 1.17; 95% CI, 0.98-1.41; P = 0.087). Abdominal aortic aneurysm-related reintervention rate was significantly lower in the OSR group (adjusted hazard ratio, 0.31; 95% CI, 0.14-0.70; P = 0.005).

CONCLUSION

Although EVAR showed somewhat superior perioperative outcomes for rAAA, the long-term outcomes of EVAR after excluding initial 3 months were significantly worse than OSR. When anatomically feasible for both treatments, the perioperative mortality risk and reasonable prospects of long-term survival should be considered in rAAA.

Outcomes and Economic Impact of Hypogastric Artery Management During Elective Endovascular Aortic Repair for Aorto-Iliac Aneurysms

BACKGROUND

To analyze clinical outcomes and perform a macro-costing evaluation of endovascular aortic repair (EVAR) for aorto-iliac aneurysms.

METHODS

This is a retrospective, financially unsupported, physician-initiated observational cohort study. Patients with iliac artery involvement treated with EVAR between January 1st, 2014 and December 31st, 2021 were identified. Inclusion criteria were intact aneurysm, elective EVAR with at least 1 hypogastric artery (HA) treatment, use of bifurcated endograft (EG), and at least 6 months of follow-up. Primary outcomes of interest were overall survival, freedom from aneurysm-related mortality (ARM), freedom from EVAR-related reintervention, and overall EVAR(procedure)-related costs.

RESULTS

We studied 122 (9.1%) patients: 119 (97.5%) were male and 3 (2.5%) females. Median age of patients was 76 years (range, 68.75-81). Overall, 107 (87.7%) patients had both HAs preserved according to following strategy: 45 (36.9%) with flared limbs, 13 (10.6%) with bilateral branched device, and 49 (40.2%) with a combination of flared limb on 1 side and branched device on the contralateral side. Bilateral overstenting was performed in 15 (12.3%) patients. Estimated overall survival was not different between groups of EVAR (Log-rank, P = 0.561). There was only 1 (0.8%) ARM ascertained during the follow-up. Estimated freedom from EVAR-related reintervention was not different among groups (Log-rank, P = 0.464). During the follow-up, 9 (7.4%) patients developed buttock claudication (Society for Vascular Surgery (SVS) grade 1, n = 4, SVS grade 2, n = 5), more frequently in HA overstenting (hazard ratio (HR): 3.6; 95% confidence intervals (CIs): 0.96-13.5, P = 0.058). When all cots were included, branched EVAR still carried the highest burden (P = 0.001) in comparison with the mixed subgroup, the overstenting subgroup, and the flared limbs subgroup.

CONCLUSIONS

Early mortality and pelvic ischemic syndromes rate were acceptably low in all techniques. Hypogastric artery preservation showed lower complication rate in comparison with HA overstenting which, however, appears to be safe an effective for option with similar overall costs for patients who are not candidates for HA preservation based on aortic anatomy.

Indocyanine green dye and its application in gastrointestinal surgery: The future is bright green

Indocyanine green (ICG) is a water-soluble fluorescent dye that is minimally toxic and widely used in gastrointestinal surgery. ICG facilitates anatomical identification of structures (e.g., ureters), assessment of lymph nodes, biliary mapping, organ perfusion and anastomosis assessment, and aids in determining the adequacy of oncological margins. In addition, ICG can be conjugated to artificially created antibodies for tumour markers, such as carcinoembryonic antigen for colorectal, breast, lung, and gastric cancer, prostate-specific antigen for prostate cancer, and cancer antigen 125 for ovarian cancer. Although ICG has shown promising results, the optimization of patient factors, dye factors, equipment, and the method of assessing fluorescence intensity could further enhance its utility. This review summarizes the clinical application of ICG in gastrointestinal surgery and discusses the emergence of novel dyes such as ZW-800 and VM678 that have demonstrated appropriate pharmacokinetic properties and improved target-to-background ratios in animal studies. With the emergence of robotic technology and the increasing reporting of ICG utility, a comprehensive review of clinical application of ICG in gastrointestinal surgery is timely and this review serves that aim.

Identification of Perioperative Procedural and Hemodynamic Risk Factors for Developing Colonic Ischemia after Ruptured Infrarenal Abdominal Aortic Aneurysm Surgery: A Single-Centre Retrospective Cohort Study

(1) Background: This retrospective study evaluated perioperative and intensive care unit (ICU) variables to predict colonic ischemia (CI) after infrarenal ruptured abdominal aortic aneurysm (RAAA) surgery. (2) Materials and Methods: We retrospectively analyzed the data of the patients treated for infrarenal RAAA from January 2011 to December 2020 in our hospital. (3) Results: A total of 135 (82% male) patients were admitted to ICU after treatment of infrarenal RAAA. The median age of all patients was 75 years (IQR 68-81 years). Of those, 24 (18%) patients developed CI, including 22 (92%) cases within the first three postoperative days. CI was found more often after open repair compared to endovascular treatment (22% vs. 5%, p = 0.021). Laboratory findings in the first seven PODs revealed statistically significant differences between CI and non-CI patients for serum lactate, minimum pH, serum bicarbonate, and platelet count. Norepinephrine (NE) was used in 92 (68%) patients during ICU stay. The highest daily dose of norepinephrine was administered to CI patients at POD1. Multivariable analysis revealed that NE > 64 µg/kg (RD 0.40, 95% CI: 0.25-0.55, p < 0.001), operating time ≥ 200 min (RD 0.18, 95% CI: 0.05-0.31, p = 0.042), and pH < 7.3 (RD 0.21, 95% CI: 0.07-0.35, p = 0.019), significantly predicted the development of CI. A total of 23 (17%) patients died during the hospital stay, including 8 (33%) patients from the CI group and 15 (7%) from the non-CI group (p = 0.032). (4) Conclusions: CI after RAAA is a sever complication occurring most frequently within the first 3 postoperative days. Our study identified many surrogate markers associated with colonic ischemia after aortic RAAA, including norepinephrine dose > 64 µg/kg, operating time ≥ 200 min, and PH < 7.3. Future studies are needed to support these results.

The Importance of the Hypogastric Artery Preservation during Treatment for Aortoiliac Aneurysms: A Prospective Single-Center Study

BACKGROUND

To determine the importance of the hypogastric artery for the outcomes of survival, endoleaks, reinterventions, buttock claudication (BC), and perioperative mortality rate (PMR) in patients with aortoiliac aneurysms (AIA) receiving endovascular or open surgical (OS) repair.

METHODS

This was a prospective consecutive cohort study of patients with AIA who underwent endovascular treatment or OS repair during the period of 2010-2021. Endovascular repair was performed with use of aortoiliac endoprosthesis associated with internal iliac artery (IIA) coil embolization and/or with iliac branch endoprosthesis (IBE) in order to preserve the IIA. The AIA OS repairs were performed with the artery ligation in order to exclude the IIA, or in some cases, the exclusion of the IIA was performed with an endosuture in the proximal stump of the artery. Three groups were identified in the postprocedural period: group 0 (no hypogastric arteries (HAs) preserved), group 1 (1 hypogastric artery preserved), and group 2 (2 hypogastric arteries preserved).

RESULTS

A total of 91 patients were submitted to OS or endovascular surgery. Regarding the HA patency, there were 17 patients in group 0, 45 patients in group 1, and 29 patients in group 2. There were 17 cases of bowel ischemia (BI) (94.1% in group 0, 5.9% in group 1, and no cases in group 2, P < 0.001) most of them in group 0, with statistical significance, 12 cases of BC (91.7% in group 0, 8.3% in group 1, and no cases in group 2, P < 0.001), most of them in group 0, with statistical significance. The perioperative mortality was 14.3%, 13 patients (9 patients - 52.9% group 0, 3 patients - 6.7% group 1, and 1 patient - 3.4% group 2, P < 0.001). The linear regression analysis for survival rates showed that BI [P = 0.026 to hazard ratio (HR) = 1.69], emergency aortoiliac repair (P < 0.001, HR = 8.86), and number of HAs (P < 0.001, HR = 5.46) in postoperative were related to poorer survival rates in both univariate and multivariate analysis. The linear regression analysis showed that the number of HAs (P < 0.001, HR = 3.61) in postoperative, emergency aortoiliac repair (P = 0.002, HR 3.233), and cardiac disease (P = 0.048, HR = 3.84) were related to BI.

CONCLUSIONS

In conclusion, the number of HA is crucial for adequate and safe outcomes after abdominal aortic aneurysm (AAA) repair. The main factors related to death were BI, emergency aortoiliac repair, and the number of HAs preserved. Moreover, the main factors related to BI were the number of HAs in postoperative, emergency aortoiliac repair, and cardiac disease.

Intraoperative Indocyanine Green Imaging for the Evaluation of Blood Perfusion Area in Cancer of the Splenic Flexure With an Occluded Inferior Mesenteric Artery: A Report of Two Cases

Radical resection for cancer of the splenic flexure requires careful consideration of the dissection line so that blood flow in the remnant bowel is maintained, particularly when the root of the inferior mesenteric artery (IMA) is already occluded. Intraoperative indocyanine green (ICG) imaging is a promising method for evaluating blood perfusion of organs and vessels. However, there are few reports on the use of ICG to determine the dissection line in patients with altered blood flow. In this article, we describe two cases of successful resection of splenic flexure cancer (SFC) in patients with an occluded IMA under ICG guidance. Case one was a 76-year-old man with a diagnosis of stage III SFC who had previously undergone endovascular aortic repair without reimplantation of the IMA. Intraoperative ICG imaging revealed that the left side of the colon was perfused mainly by the left branch of the middle colic artery (MCA). We performed a hemicolectomy with preservation of the MCA-left colic artery (LCA) arcade and resected an enlarged lymph node en bloc. Case two was a 77-year-old man with a diagnosis of stage II SFC in whom the root of the IMA appeared to be occluded by arteriosclerosis. Computed tomography showed that the LCA was anastomosed to the accessory middle colic artery (AMCA) while the left branch of the MCA was joined to the marginal artery. Intraoperative ICG imaging revealed that the left side of the colon was perfused by the AMCA and not the MCA. By preserving the AMCA-LCA arcade, we were able to safely divide the left branch of the MCA. Both patients were discharged with no symptoms of bowel ischemia or recurrence of cancer during follow-up. Interindividual variation in vessel branching patterns and dominant vessels in the descending and distal transverse colon may result from congenital factors or acquired disease. Detailed information on blood perfusion is required to avoid postoperative bowel ischemia. This report is the first to focus on patients with SFC and altered blood flow. We show that ICG imaging might be a reasonable option for determining an adequate surgical dissection area.

The Effect of Smoking Status on Perioperative Morbidity and Mortality after Open and Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVES

This study quantifies the extent to which active tobacco smoking is deleterious towards outcomes following open and endovascular AAA repair.

METHODS

Open and endovascular abdominal aortic aneurysm (AAA) repairs between January 2003 and June 2020 in the Vascular Quality Initiative (VQI) were queried. Rupture, symptomatic status, and lack of 90 day follow up were exclusions. Patients were then placed into one of six groups : open AAA with active smoking (n=3788); open AAA with prior smoking (n=4614); open AAA never smokers (817); endovascular AAA active smokers (n=14173); endovascular AAA former smokers (n=25,831); and, endovascular AAA never smokers (n=6064). Comparison of baseline characteristics, co-morbidities, and adverse outcomes across each of the 6 cohorts was performed with open AAA in active smokers serving as the reference. Sub-analysis investigating open AAA repair in active smokers relative to open AAA in patients confirmed in VQI to have quit smoking between 30 and 90 days before surgery was performed. Smoking cessation for a minimum of 30 days before surgery was required to fall into the former smoker category.

RESULTS

In comparing open AAA in active smokers to open AAA in former and never smokers, the active smokers experienced significantly higher rates of pneumonia (P<.001). Combined additive morbidity and mortality was highest (54%) in active smokers (P<.001 relative to all cohorts other than open AAA former smokers P=.21). Smoking status did not impact morbidity or mortality incidence across individuals undergoing EVAR. Binary logistic regression for all AAA patients (open and endovascular combined) revealed those with any history of smoking to be more likely to experience 90 day mortality (adjusted OR 2.5 (2.2-2.9), P<.001) relative to never-smokers. Active smokers were similarly more likely to experience 90 day mortality than prior/never smokers combined (OR 1.23 (1.07-1.38), P<.001). Mortality within 90 days was significantly more likely (P<.001) with aging, female gender, larger aneurysms, preoperative history of congestive heart failure, chronic obstructive pulmonary disease, chronic renal insufficiency, peripheral artery disease, body mass index under 20 and over 35 mg/kg². Diabetes and coronary artery disease were also associated with 90 day mortality (P= .045 and .049 respectively). Quitting smoking between 30 and 90 days before open repair reduced combined additive morbidity and mortality relative to active smokers (OR 1.34, P =.038).

CONCLUSIONS

Smoking cessation 30 days before open AAA repair reduces perioperative morbidity and mortality. Smoking status does not impact morbidity and mortality in patients undergoing endovascular AAA repair. When combining all patients (open and endovascular), higher rates of 90 day mortality are associated with any history of smoking, aging, female gender and advanced pre-existing co-morbidities on multivariable analysis.

Safety of the endovascular aneurysm repair procedure: real-world evidence using interrupted-time series analysis

OBJECTIVES

In Taiwan, endovascular aneurysm repair for treating abdominal aortic aneurysms (AAA) was introduced in 2004 and became reimbursable in February 2010. We evaluated the real-world practice and safety of endovascular aneurysm repair in Taiwan.

METHODS

Patients who underwent repair operations for AAA (open or endovascular) from 2000 to 2016 were enrolled (n = 11485). Outcome statistics (during the index hospitalization: length of stay, rate of ischaemic bowel disease and 30-day mortality; after discharge: 30-day readmission rate, 2-year mortality, 2-year reintervention rate and 2-year paraplegia rate) were calculated for each half-year cohort. Propensity score-based stabilized weights were used to balance covariates among each half-year cohort. Interrupted time-series analysis was then performed.

RESULTS

The elective and emergency ratio of AAA repair was 50:50 from 2000 to 2004 and became 60:40 from 2010 to 2016. The half-year rate of endovascular aneurysm repair was 0% in 2000 to 2004/06, 83.16% in 2010 and 98.1% in 2016. Interrupted time series analysis revealed that after endovascular aneurysm repair became reimbursable, both elective and emergency groups had a reduction in length of stay (-4.2 days, P < 0.0001; -1.5 days, P = 0.0928) and 30-day mortality (-5.22%, P = 0.0702; -7.76%, P = 0.0086) but a significant increase in the reintervention rate (5.05%, P = 0.0031; 4.36%, P = 0.0097).

CONCLUSIONS

Endovascular aneurysm repair was predominantly used in treating AAAs after it was reimbursed in Taiwan. Endovascular aneurysm repair is efficacious regarding short-term outcomes but increased the 2-year reintervention rate in both groups.

Association of Serum Creatinine Level with Prognosis of Laparotomy for Acute Mesenteric Ischemia after Cardiovascular Surgery

Introduction

Acute mesenteric ischemia is a life-threatening complication after cardiovascular surgery with a mortality rate of 52.9–81.3%. However, few studies have evaluated the predictors of clinical outcome after treatment for acute mesenteric ischemia following cardiovascular surgery. Therefore, this study aimed to elucidate prognostic factors in patients who underwent laparotomy for acute mesenteric ischemia after cardiovascular surgery.

Methods

We retrospectively analyzed 29 patients (20 men and 9 women; median age, 71.0 years) who underwent laparotomy for acute mesenteric ischemia after cardiovascular surgery between January 2010 and August 2020. These patients were classified into the survivor group (comprising patients who were discharged or referred to another hospital, n = 16) and the nonsurvivor group (comprising those who experienced in-hospital mortality, n = 13). We compared clinical parameters between the groups to identify the predictors of outcomes.

Results

More patients in the nonsurvivor group underwent emergency cardiovascular surgery (62.5% vs. 100%, p = 0.017) and received hemodialysis (12.5% vs. 61.5%, p = 0.008) at the onset of acute mesenteric ischemia than those in the survivor group. The prelaparotomy serum creatinine level was higher in the nonsurvivor group than in the survivor group (1.27 vs. 2.33 mg/dL, p = 0.004). Logistic regression analysis revealed an association between preoperative serum creatinine level and in-hospital mortality (odds ratio 5.047, p = 0.046), and Cox regression analysis demonstrated a relationship between serum creatinine level and in-hospital mortality (hazard ratio 1.610, p = 0.009). The area under the curve (receiver operating characteristic analysis) for the serum creatinine level was 0.813. Furthermore, the optimal cutoff value of the serum creatinine level was 1.59 mg/dL with a sensitivity and specificity of 0.846 and 0.687, respectively, in predicting in-hospital mortality.

Conclusions

The elevated serum creatinine level was associated with a poor clinical outcome after surgery for acute mesenteric ischemia following cardiovascular surgery.

Gluteal compartment syndrome: A systematic review and meta-analysis

INTRODUCTION

Gluteal compartment syndrome is a rare but devastating condition with limited characterization in the literature. The purpose of our systematic review, case series, and meta-analysis is to synthesize the current literature and provide recommendations on how to prevent gluteal compartment syndrome, identify at-risk patients, and avoid delays in diagnosis and treatment.

METHODS

International Classification of Disease codes were used to identify patients at our institution. PubMed, MEDLINE, and the Cochrane Library were searched to identify case reports between 1972 and March 1st, 2018. Cases were analyzed based on demographics, etiology, presentation, symptoms, diagnosis, treatment, and outcomes.

RESULTS

139 cases - 13 from our institution and 126 previously published - were included. The most common etiologies were postoperative (41%), prolonged immobilization secondary to substance abuse or loss of consciousness (35%) and trauma (19%). 89% were male, mean age was 45 years (range, 16-74), and mean body mass index was 41 kg/m². Rhabdomyolysis and sciatic neuropathy were identified in 94% and 74% of patients, respectively. Fasciotomy was performed in 80% of patients. Overall, 93% of patients survived. However, 41% of patients suffered prolonged neurologic dysfunction. In patients with an initial neurologic deficit, there was a higher rate of permanent neurological deficit in patients treated medically than those treated surgically (12/14 vs 29/61, p=0.0153), but no statistical difference in mortality (0/14 vs 4/61, p=1). In patients without initial neurologic deficit, there were no statistical differences in rates of permanent neurological deficit (0/7 vs 2/20, p=1) or mortality (0/7 vs 3/20, p=0.545) between those receiving medical or surgical treatment.

DISCUSSION

Gluteal compartment syndrome is an orthopaedic emergency that may be more prevalent and associated with higher morbidity and mortality than previously recognized. Risk factors may include prolonged surgical duration, immobilization secondary to substance abuse, and pelvic trauma. Intraoperative precautions and postoperative surveillance are recommended in obese patients undergoing prolonged procedures. Fasciotomies improve neurologic outcomes in patients presenting with an initial neurologic deficit. In patients who are neurologically intact on presentation, medical management with neurologic function surveillance may be the optimal initial treatment. Fasciotomies do not impact mortality. Additionally, a treatment algorithm is provided.

Anatomical characteristics associated with superior mesenteric artery stent graft placement during fenestrated para/suprarenal aneurysm repair

OBJECTIVE

According to instructions for use, fenestrated aneurysm repair (FEVAR) with the Cook Zenith fenestrated endograft (ZFEN) requires at least 4 mm of non-aneurysmal infra-renal neck length and superior mesenteric artery (SMA) stenting is optional. This study evaluates the outcomes of FEVAR with SMA stent grafting relative to SMA scallops or unstented fenestrations and anatomical differences there-in.

METHODS

Single-institution retrospective analysis of patients who underwent FEVAR with SMA scallop or large fenestration with and without SMA stent grafting from June 2012 to May 2020 following Institutional Review Board approval.

RESULTS

Of the 203 aneurysms repaired with ZFENs, 127 were included in our analysis with 55 stent grafted SMA fenestrations, 38 unstented SMA fenestrations and 34 SMA scallops. Technical success was achieved in all patients. Operative times were longer (335.5 ± 16.4 vs 265.0 ± 12.8 vs 269.0 ± 12.7 mins, p < 0.001) and transfusion rates were higher (33% vs 8% vs 18%, p = 0.01) in the SMA stent graft group but fluoroscopy time (65.4 ± 3.76 vs 58.3 ± 3.94 vs 51.4 ± 4.75 mins, p = 0.05) and contrast volume (92.2 ± 5.17 vs 87.1 ± 6.73 vs 93.1 ± 5.89 mL, p = 0.84) were not significantly different. Anatomically, patients that underwent ZFEN with SMA stent grafting had less infrarenal neck (1.73 ± 1.18 vs 4.92 ± 1.16 vs 6.28 ± 1.42 mm, p = 0.03) and shorter infra-SMA neck length (10.3 ± 1.39 vs 23.9 ± 1.24 vs 26.8 ± 1.67 mm, p < 0.001). In the SMA stent graft group, 1 had small bowel necrosis following embolization of an intra-operatively perforated jejunal branch and 2 had colonic ischemia of unclear etiology with patent SMA stent grafts on imaging. Endograft migration and SMA occlusion with bowel ischemia occurred in 1 patient in the SMA fenestration group. Overall mortality (24% vs 21% vs 18%, p = 0.82) and 30-day mortality (5% vs 3% vs 3%, p = 0.80) were comparable between the 3 groups. In addition, the incidence of type 3 endoleak (5% vs 3% vs 3%, p = 0.45) and need for re-intervention (20% vs 18% vs 12%, p = 0.60) were similar across all groups. Mean follow-up duration was longer in the SMA scallop group which can be attributed to 82% of these occurring in the first half of the study period.

CONCLUSION

Despite the added technical complexity, SMA stenting enables FEVAR in patients with pararenal and suprarenal aneurysms with high rates of technical success and no increased risk of mortality, major adverse events, type 3 endoleak, or re-intervention.

Female sex is independently associated with in-hospital mortality after endovascular aortic repair for ruptured aortic aneurysm

OBJECTIVE

Endovascular aortic repair (EVAR) can treat anatomically compatible ruptured abdominal aortic aneurysms (rAAA), but registry data suggests that women undergo more open abdominal aneurysm repairs than men. We evaluate in-hospital outcomes of EVAR for rAAA by sex.

METHODS

The Vascular Quality Initiative (VQI) registry was queried from 2013 to 2019 for rAAA patients treated with EVAR. Univariate analysis was performed with Student's t-test and chi-squared tests. Multivariable logistic regression was then performed to assess the association between female sex and inpatient mortality.

RESULTS

1775 patients were included (23.8% female). Female rAAA patients were older (p < 0.01) and weighed less (p < 0.01). They were less likely to have smoked (p <. 001) and had lower creatinine (1.29 vs 1.43, p <0.01) and hemoglobin (10.7 vs 11.7, p < 0.01). Women had smaller maximum aortic diameters (74 vs 66 mm, p < 0.01) and were less likely to have iliac aneurysms (p <.001). Women were more likely to have concomitant femoral endarterectomy (8.5% vs 4.6%, p=.03). Despite having no significant difference in complication or reintervention rates, women had higher rates of in-hospital mortality (45.9% vs 34.5%, p < 0.01). In a logistic regression model for predictors of in-hospital mortality (χ² < .01), increased age (OR 1.08, p < 0.01), female sex (OR 1.7, p=0.02), preoperative cardiac arrest (OR 5.29, p<0.01), concurrent iliac stenting (OR 2.38, p =0.02), postoperative mesenteric ischemia (OR 2.51, p<0.01) and postoperative transfusion (OR 1.06, p <0.01) were independently associated with in-hospital mortality. Increased preoperative hemoglobin was protective (OR 0.89, p < 0.01) CONCLUSIONS: Female sex is independently associated with in-hospital mortality after EVAR for rAAA, suggesting a relationship beyond anatomical, biochemical, and procedural covariates.

[Debate on Infrarenal AAA in Young and Fit Patients ('Fit for Open Repair'): Open Repair is Safe and Long-term Results are Better]

Endovascular aortic repair, initially developed for patients at prohibitively high risk for an open repair, has undergone significant technical evolution and refinement and has emerged as the preferred treatment option for patients with an infrarenal aortic aneurysm. However, analysis of long-term data of the randomised studies revealed inferior results with regards to survival and freedom-from-reintervention after eight years. Open aortic repair has been performed for more than seven decades and especially for the younger patients with few comorbidities, results are excellent. Potential drawbacks of open repair like incisional hernias, erectile dysfunction and quality of life can either be effectively prevented (mesh reinforcement) or actually failed to show a significant difference compared to open repair in recent studies. Therefore, meticulous assessment of patient comorbidites using validated parameters is the key element for decision-making and parameters such as young age, low comorbidity profile, large aneurysm and presence of atopic renal arteries or a dominant inferior mesenteric artery should prompt a recommendation of open repair.

Short-term outcomes of open surgical abdominal aortic aneurysm repair from the Dutch Surgical Aneurysm Audit

Background

The sharp decrease in open surgical repair (OSR) for abdominal aortic aneurysm (AAA) has raised concerns about contemporary postoperative outcomes. The study was designed to analyse the impact of complications on clinical outcomes within 30 days following OSR.

Methods

Patients who underwent OSR for intact AAA registered prospectively between 2016 and 2019 in the Dutch Surgical Aneurysm Audit were included. Complications and outcomes (death, secondary interventions, prolonged hospitalization) were evaluated. The adjusted relative risk (aRr) and 95 per cent confidence intervals were computed using Poisson regression. Subsequently, the population-attributable fraction (PAF) was calculated. The PAF reflects the expected percentage reduction of an outcome if a complication were to be completely prevented.

Results

A total of 1657 patients were analysed. Bowel ischaemia and renal complications had the largest impact on death (aRr 12·44 (95 per cent c.i. 7·95 to 19·84) at PAF 20 (95 per cent c.i. 8·4 to 31·5) per cent and aRr 5·07 (95 per cent c.i. 3·18 to 8.07) at PAF 14 (95 per cent c.i. 0·7 to 27·0) per cent, respectively). Arterial occlusion had the greatest impact on secondary interventions (aRr 11·28 (95 per cent c.i. 8·90 to 14·30) at PAF 21 (95 per cent c.i. 14·7 to 28·1) per cent), and pneumonia (aRr 2·52 (95 per cent c.i. 2·04 to 3·10) at PAF 13 (95 per cent c.i. 8·3 to 17·8) per cent) on prolonged hospitalization. Small effects were observed on outcomes for other complications.

Conclusion

The greatest clinical impact following OSR can be made by focusing on measures to reduce the occurrence of bowel ischaemia, arterial occlusion and pneumonia.

Transrectal intracolon cooling prevents paraplegia and mortality in a rat model of aortic occlusion-induced spinal cord ischemia

OBJECTIVE

Spinal cord ischemia-reperfusion injury (SC-IRI) occurs in many medical conditions such as aneurysm surgical repair but no treatment of SC-IRI is available in clinical practice. The objective of the present study was to develop a novel medical device for the treatment of SC-IRI.

METHODS

A rat model of SC-IRI was used. A novel transrectal intracolon (TRIC) temperature management device was developed to maintain an intracolon wall temperature at either 37°C (TRIC37°C) or 12°C (TRIC12°C). The upper body temperature was maintained as close as possible to 37°C in both groups. A 2F Fogarty balloon catheter was inserted via the left common carotid artery to block the distal aortic blood flow to the spinal cord. The proximal blood pressure was controlled by the withdrawal and infusion of blood via the jugular vein catheter, such that the distal tail artery blood pressure was maintained at ∼10 mmHg for 13 and 20 minutes, respectively. Next, the balloon was deflated, and TRIC temperature management was continued for an additional 30 minutes to maintain the colon wall temperature at either 37°C or 12°C during the reperfusion period.

RESULTS

All the rats subjected to 13 minutes of spinal cord ischemia in the TRIC37°C group had developed paraplegia during the postischemic phase. In striking contrast, TRIC at 12°C completely prevented the paraplegia, dramatically improved the arterial blood gas parameters, and avoided the histopathologic injuries to the spinal cord in rats subjected to 13 minutes of spinal cord ischemia. Furthermore, TRIC12°C allowed for the extension of the ischemia duration from 13 minutes to 20 minutes, with significantly reduced functional deficits.

CONCLUSIONS

Directly cooling the intestine focally with the TRIC device offered an exceptional survival rate and functional improvement after aortic occlusion-induced spinal cord ischemia.

Editor's Choice - Systematic Review and Meta-Analysis of Sex Specific Differences in Adverse Events After Open and Endovascular Intact Abdominal Aortic Aneurysm Repair: Consistently Worse Outcomes for Women

OBJECTIVE

Previously, reports have shown that women experience a higher mortality rate than men after elective open (OAR) and endovascular (EVAR) repair of abdominal aortic aneurysm (AAA). With recent improvements in overall AAA repair outcomes, this study aimed to identify whether sex specific disparity has been ameliorated by modern practice, and to define sex specific differences in peri- and post-operative complications and pre-operative status; factors which may contribute to poor outcome.

METHODS

This was a systematic review, meta-analysis, and meta-regression of sex specific differences in 30 day mortality and complications conducted according to PRISMA guidance (Prospero registration CRD42020176398). Papers with ≥ 50 women, reporting sex specific outcomes, following intact primary AAA repair, from 2000 to 2020 worldwide were included; with separate analyses for EVAR and OAR. Data sources were Medline, Embase, and CENTRAL databases 2005 - 2020 searched using ProQuest Dialog.

RESULTS

Twenty-six studies (371 215 men, 65 465 women) were included. Meta-analysis and meta-regression indicated that sex specific odds ratios (ORs) for 30 day mortality were unchanged from 2000 to 2020. Mortality risk was higher in women for OAR and more so for EVAR (OR [95% CI] 1.49 [1.37 - 1.61]; 1.86 [1.59 - 2.17], respectively) and this remained following multivariable risk adjustment. Transfusion, pulmonary complications, and bowel ischaemia were more common in women after OAR and EVAR (OAR: ORs 1.81 [1.60 - 2.04], 1.40 [1.28 - 1.53], 1.54 [1.36 - 1.75]; EVAR: ORs 2.18 [2.08 - 2.29] 1.44 [1.17 - 1.77], 1.99 [1.51 - 2.62], respectively). Arterial injury, limb ischaemia, renal and cardiac complications were more common in women after EVAR (ORs 3.02 [1.62 - 5.65], 2.13 [1.48 - 3.06], 1.46 [1.22 - 1.72] and 1.19 [1.03 - 1.37], respectively); the latter was associated with greater mortality risk on meta-regression.

CONCLUSION

Increased mortality risk for women following AAA repair remains. Women had a higher incidence of transfusion, pulmonary and bowel complications after EVAR and OAR. Higher mortality risk ratios for EVAR may result from cardiac complications, additional arterial injury, and embolisation, leading to renal and limb ischaemia. These findings indicate possible causes for observed outcome disparities and targets for quality improvement.

Postoperative bowel complications after non-shunt-related neurosurgical procedures: case series and review of the literature

Postoperative bowel complications after non-shunt-related neurosurgical procedures are relatively rare. In an effort to identify the primary risk factors, we evaluated postoperative bowel complications in cranial, endovascular, and spinal procedures in neurosurgery patients using our own institutional case series along with a literature review.We identified severe postoperative bowel complications that occurred at our institution after non-shunt-related neurosurgical procedures between July 2016 and December 2018. We also completed a systematic review of PubMed/MEDLINE using search terms related to bowel complications.At our institution, 7 patients (average age 49.7 ± 9.5 years, range 34-60; no apparent sex predilection) had severe postoperative bowel complications after undergoing a total of 10 neurosurgical procedures. Diagnosis was on average 1 week postoperatively (range 5-13 days), and the time between radiographic/clinical diagnosis and either surgery or death was 1.3 ± 1.4 days (range 0-4 days). Bowel perforation occurred in 4 patients. Five of the patients died, 3 as a direct result of the bowel complication. In the literature review, we identified 6487 spine and 66 cranial and/or endovascular bowel complications after neurosurgical procedures.Our case series and literature review demonstrate that severe postoperative bowel complications after non-shunt-related neurosurgical procedures, while rare, carry significant morbidity/mortality despite prompt and aggressive management. These can also happen without direct injury to bowel tissue, instead occurring as sequelae of inflammatory processes, as well as from delayed mobility, extended use of opiate narcotics, and lack of standardized protocols to ensure early bowel movements that likely stems from unfamiliarity with this potentially devastating complication.

Influence of perioperative risk factors on the development of transmural colonic ischemia after open repair of ruptured abdominal aortic aneurysm

BACKGROUND

Development of colonic ischemia (CI) after ruptured abdominal aortic aneurysm (RAAA) treatment is a lethal complication with perioperative mortality reported to be high as 50%. Therefore, the main goal of this study was to identify pre-, intra- and postoperative risk factors associated with CI in patients undergoing open repair (OR) due to RAAA, that might help to select patients who are more prone to develop CI.

METHODS

This was a single-center prospective cohort study on patients with RAAA undergoing OR between January 1st 2018 and July 1st 2019, at the Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia. During this period 89 patients were treated due to RAAA and all were included in the study. The primary endpoint was grade III CI, or transmural necrosis, diagnosed by laparotomy.

RESULTS

Out of 89 patients operated due to RAAA, CI was diagnosed in 14 (15.73%). During the operation, patients with CI had a longer duration of hypotension (42.86±35.82 vs 24.13±23.48, p=.021) and more common significant hypotension (54.54% vs 14.66%, p=.024). In the postoperative course, patients with CI had more common signs of abdominal compartment syndrome (71.42% vs 25.33%, p=.001) and higher mortality rate (78.57% vs 29.33%, p=.001). The univariate regression model showed that one of the most significant factors that were associated with CI were age higher than 75 years, significant hypotension lasting more than one hour, organ lesion, development of abdominal compartment syndrome and higher potassium values on third and fourth quartile.

CONCLUSIONS

Grade III colon ischemia (transmural) remains the important cause of mortality after ruptured abdominal aortic aneurysm repair. We identified pre- and intraoperative and postoperative risk factors that could improve the selection of patients for primary open abdomen treatment or early exploratory laparotomy in order to prevent or timely diagnose colon ischemia.

Focal intra-colon cooling reduces organ injury and systemic inflammation after REBOA management of lethal hemorrhage in rats

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a lifesaving maneuver for the management of lethal torso hemorrhage. However, its prolonged use leads to distal organ ischemia-reperfusion injury (IRI) and systemic inflammatory response syndrome (SIRS). The objective of this study is to investigate the blood-based biomarkers of IRI and SIRS and the efficacy of direct intestinal cooling in the prevention of IRI and SIRS. A rat lethal hemorrhage model was produced by bleeding 50% of the total blood volume. A balloon catheter was inserted into the aorta for the implementation of REBOA. A novel TransRectal Intra-Colon (TRIC) device was placed in the descending colon and activated from 10 min after the bleeding to maintain the intra-colon temperature at 37 °C (TRIC37°C group) or 12 °C (TRIC12°C group) for 270 min. The upper body temperature was maintained at as close to 37 °C as possible in both groups. Blood samples were collected before hemorrhage and after REBOA. The organ injury biomarkers and inflammatory cytokines were evaluated by ELISA method. Blood based organ injury biomarkers (endotoxin, creatinine, AST, FABP1/L-FABP, cardiac troponin I, and FABP2/I-FABP) were all drastically increased in TRIC37°C group after REBOA. TRIC12°C significantly downregulated these increased organ injury biomarkers. Plasma levels of pro-inflammatory cytokines TNF-α, IL-1b, and IL-17F were also drastically increased in TRIC37°C group after REBOA. TRIC12°C significantly downregulated the pro-inflammatory cytokines. In contrast, TRIC12°C significantly upregulated the levels of anti-inflammatory cytokines IL-4 and IL-10 after REBOA. Amazingly, the mortality rate was 100% in TRIC37°C group whereas 0% in TRIC12°C group after REBOA. Directly cooling the intestine offered exceptional protection of the abdominal organs from IRI and SIRS, switched from a harmful pro-inflammatory to a reparative anti-inflammatory response, and mitigated mortality in the rat model of REBOA management of lethal hemorrhage.

Gut-Derived Exosomes Mediate Memory Impairment After Intestinal Ischemia/Reperfusion via Activating Microglia

Intestinal ischemia/reperfusion is a grave condition with high morbidity and mortality in perioperative and critical care settings and causes multiple organ injuries beyond the intestine, including brain injury. Exosomes act as intercellular communication carriers by the transmission of their cargo to recipient cells. Here, we investigate whether exosomes derived from the intestine contribute to brain injury after intestinal ischemia/reperfusion via interacting with microglia in the brain. Intestinal ischemia/reperfusion was established in male C57/BL mice by clamping the superior mesenteric artery for 30 min followed by reperfusion. The sham surgery including laparotomy and isolation of the superior mesenteric artery without occlusion was performed as control. Male C57 mouse was intracerebral ventricular injected with intestinal exosomes from mice of intestinal ischemia/reperfusion or sham surgery. Primary microglia were cocultured with intestinal exosomes; HT-22 cells were treated with intestinal exosomes or microglia conditioned media. Intestinal ischemia/reperfusion-induced microglial activation, neuronal loss, synaptic stability decline, and cognitive deficit. Intracerebral ventricular injection of intestinal exosomes from intestinal ischemia/reperfusion mice causes microglial activation, neuronal loss, synaptic stability decline, and cognitive impairment. Microglia can incorporate intestinal exosomes both in vivo and in vitro. Microglia activated by intestinal exosomes increases neuron apoptotic rate and decreases synaptic stability. This study indicates that intestinal exosomes mediate memory impairment after intestinal ischemia/reperfusion via activating microglia. Inhibiting exosome secretion or suppressing microglial activation can be a therapeutic target to prevent memorial impairment after intestinal ischemia/reperfusion.

The Association of Coloproctology of Great Britain and Ireland consensus guidelines in emergency colorectal surgery

AIM

There is a requirement for an expansive and up to date review of the management of emergency colorectal conditions seen in adults. The primary objective is to provide detailed evidence-based guidelines for the target audience of general and colorectal surgeons who are responsible for an adult population and who practise in Great Britain and Ireland.

METHODS

Surgeons who are elected members of the Association of Coloproctology of Great Britain and Ireland Emergency Surgery Subcommittee were invited to contribute various sections to the guidelines. They were directed to produce a pathology-based document using literature searches that were systematic, comprehensible, transparent and reproducible. Levels of evidence were graded. Each author was asked to provide a set of recommendations which were evidence-based and unambiguous. These recommendations were submitted to the whole guideline group and scored. They were then refined and submitted to a second vote. Only those that achieved >80% consensus at level 5 (strongly agree) or level 4 (agree) after two votes were included in the guidelines.

RESULTS

All aspects of care (excluding abdominal trauma) for emergency colorectal conditions have been included along with 122 recommendations for management.

CONCLUSION

These guidelines provide an up to date and evidence-based summary of the current surgical knowledge in the management of emergency colorectal conditions and should serve as practical text for clinicians managing colorectal conditions in the emergency setting.

Nationwide Study to Predict Colonic Ischemia after Abdominal Aortic Aneurysm Repair in The Netherlands

BACKGROUND

Colonic ischemia remains a severe complication after abdominal aortic aneurysm (AAA) repair and is associated with a high mortality. With open repair being one of the main risk factors of colonic ischemia, deciding between endovascular or open aneurysm repair should be based on tailor-made medicine. This study aims to identify high-risk patients of colonic ischemia, a risk that can be taken into account while deciding on AAA treatment strategy.

METHODS

A nationwide population-based cohort study of 9,433 patients who underwent an AAA operation between 2014 and 2016 was conducted. Potential risk factors were determined by reviewing prior studies and univariate analysis. With logistic regression analysis, independent predictors of intestinal ischemia were established. These variables were used to form a prediction model.

RESULTS

Intestinal ischemia occurred in 267 patients (2.8%). Occurrence of intestinal ischemia was seen significantly more in open repair versus endovascular aneurysm repair (7.6% vs. 0.9%; P < 0.001). This difference remained significant after stratification by urgency of the procedure, in both intact open (4.2% vs. 0.4%; P < 0.001) and ruptured open repair (15.0% vs. 6.2%); P < 0.001). Rupture of the AAA was the most important predictor of developing intestinal ischemia (odds ratio [OR], 5.9, 95% confidence interval [CI] 4.4-8.0), followed by having a suprarenal AAA (OR 3.4; CI 1.1-10.6). Associated procedural factors were open repair (OR 2.8; 95% CI 1.9-4.2), blood loss >1L (OR 3.6; 95% CI 1.7-7.5), and prolonged operating time (OR 2.0; 95% CI 1.4-2.8). Patient characteristics included having peripheral arterial disease (OR 2.4; 95% CI 1.3-4.4), female gender (OR 1.7; 95% CI 1.2-2.4), renal insufficiency (OR 1.7; 1.3-2.2), and pulmonary history (OR 1.6; 95% CI 1.2-2.2). Age <68 years proved to be a protective factor (OR 0.5; 95% CI 0.4-0.8). Associated mortality was higher in patients with intestinal ischemia versus patients without (50.6% vs. 5.1%, P < 0.001). Each predictor was given a score between 1 and 4. Patients with a score of ≥10 proved to be at high risk. A prediction model with an excellent AUC = 0.873 (95% CI 0.855-0.892) could be formed.

CONCLUSIONS

One of the main risk factors is open repair. Several other risk factors can contribute to developing colonic ischemia after AAA repair. The proposed prediction model can be used to identify patients at high risk for developing colonic ischemia. With the current trend in AAA repair leaning toward open repair for better long-term results, our prediction model allows a better informed decision can be made in AAA treatment strategy.

Surveillance to detect colonic ischemia with extraluminal pH measurement after open surgery for abdominal aortic aneurysm

OBJECTIVE

Colonic ischemia (CI) is a life-threatening complication after aortic surgery. Postoperative surveillance of colonic perfusion might be warranted. The aim of the present study was to evaluate the safety and feasibility of postoperative extraluminal pH measurement (pHe) using colonic tonometry after open abdominal aortic aneurysm (AAA) repair.

METHODS

Before closing the abdomen after open AAA repair, a tonometric catheter was placed transabdominally in contact with the sigmoid colon serosa, similar to a drainage catheter. Extraluminal partial pressure of carbon dioxide was measured postoperatively and combined with arterial blood gas analysis to calculate the pHe. The measurements were repeated every 4 hours with simultaneous intra-abdominal pressure measurements. The threshold for colonic malperfusion was set at pHe <7.2.

RESULTS

A total of 27 patients were monitored, 12 had undergone surgery for ruptured AAAs and 15 for intact AAAs. Of the 27 patients, 4 developed clinically significant CI requiring surgery. All four cases were preceded by a prolonged (>5 hours) pHe <7.2 indicating malperfusion. A fifth patient, who, during monitoring, had had the lowest pHe of 7.21, developed mild CI with the onset after completion of monitoring, which was successfully managed conservatively. Seven patients who had had brief durations (<5 hours) of pHe <7.2 did not develop clinical signs of CI or any related adverse events.

CONCLUSIONS

Measurements of pHe using colonic tonometry indicated malperfusion in all four patients who had developed clinically significant CI. A shorter duration of low pHe was well tolerated without any signs of CI. Measurement of pHe was safe and reliable for the surveillance of colonic perfusion after open aortic surgery, indicating a promising technique. However, larger studies are needed.

Early Gastrointestinal Complications After Open Thoracoabdominal Aortic Aneurysm Repair

BACKGROUND

The present study was done to examine the incidence, predictors, and impact of early gastrointestinal (GI) complications after open thoracoabdominal aortic aneurysm repair.

METHODS

We retrospectively analyzed data from 3587 open thoracoabdominal aortic aneurysm repairs performed at our center from 1986 to 2019. We used univariate analyses and multivariable logistic regression to identify risk factors associated with GI complications, including bleeding, ischemia, obstruction, and acute pancreatitis. Adverse event was defined as operative death or persistent stroke, paraplegia, paraparesis, or renal failure necessitating dialysis.

RESULTS

Gastrointestinal complications developed after 213 repairs (5.9%). Gastrointestinal complications less often developed after extent I repair than after repairs that involved infrarenal abdominal aortic segments (ie, extent II to IV repairs; P = .003). Patients who had GI complications more often underwent endarterectomy, stenting, or bypass of visceral arteries (51.2% vs 42.2%; P = .01). Use of selective visceral perfusion did not differ between groups. Patients who had GI complications had higher rates of operative mortality (34.3% vs 6.6%) and adverse events (44.1% vs 13.2%) and had longer hospitalization (29 vs 11 days; P < .001 for all). Independent predictors of GI complications included incidental splenectomy, rupture, non-extent I repair, older age, and longer aortic cross-clamp time. Short-term, midterm, and long-term survival were poorer for patients who had GI complications (P < .001).

CONCLUSIONS

Although uncommon, early GI complications after open thoracoabdominal aortic aneurysm repair are associated with significant early and late morbidity and mortality. Development of perioperative strategies to mitigate these complications is warranted.

Disease Mechanisms of Perioperative Organ Injury

Despite substantial advances in anesthesia safety within the past decades, perioperative mortality remains a prevalent problem and can be considered among the top causes of death worldwide. Acute organ failure is a major risk factor of morbidity and mortality in surgical patients and develops primarily as a consequence of a dysregulated inflammatory response and insufficient tissue perfusion. Neurological dysfunction, myocardial ischemia, acute kidney injury, respiratory failure, intestinal dysfunction, and hepatic impairment are among the most serious complications impacting patient outcome and recovery. Pre-, intra-, and postoperative arrangements, such as enhanced recovery after surgery programs, can contribute to lowering the occurrence of organ dysfunction, and mortality rates have improved with the advent of specialized intensive care units and advances in procedures relating to extracorporeal organ support. However, no specific pharmacological therapies have proven effective in the prevention or reversal of perioperative organ injury. Therefore, understanding the underlying mechanisms of organ dysfunction is essential to identify novel treatment strategies to improve perioperative care and outcomes for surgical patients. This review focuses on recent knowledge of pathophysiological and molecular pathways leading to perioperative organ injury. Additionally, we highlight potential therapeutic targets relevant to the network of events that occur in clinical settings with organ failure.

The Effect of Hypogastric Artery Revascularization on Ischemic Colitis in Endovascular Aneurysm Repair

BACKGROUND

The objective of the study was to examine the effect of hypogastric revascularization maneuvers on the rate of postoperative ischemic colitis among patients undergoing endovascular aortoiliac aneurysm repair.

METHODS

Using the 2011-2018 Endovascular Aneurysm Repair Procedure-Targeted American College of Surgeons National Surgical Quality Improvement Program Participant Use Files, we analyzed patients undergoing elective endovascular infrarenal aortoiliac aneurysm repairs. Using multivariable modeling techniques, a cohort of patients at high risk for postoperative ischemic colitis was identified. The outcomes of this group were then compared using Pearson's chi-square testing in accordance with whether or not they underwent hypogastric revascularization.

RESULTS

Of 4753 patients undergoing endovascular aortoiliac aneurysm repair in the National Surgical Quality Improvement Program cohort, 1161 had concomitant hypogastric revascularization procedures. High-risk predictors of ischemic colitis included chronic obstructive pulmonary disease and concurrent renal artery or external iliac artery stenting. There was not a significant association between pelvic revascularization and postoperative ischemic colitis [1.0% with versus 0.5% without pelvic revascularization; adjusted odds ratio of ischemic colitis with revascularization 2.07 (0.96, 4.46); P = 0.06] after adjustment for patient- and procedure-related factors. In a subgroup analysis of patients with a distal aneurysm extent beyond the common iliac artery, the incidence of ischemic colitis was significantly lower in patients without pelvic revascularization (0.1% versus 1.6%, P = 0.004).

CONCLUSIONS

Our analysis of patients undergoing elective endovascular repair of infrarenal aortoiliac aneurysmal disease did not find a reduced incidence of postoperative ischemic colitis in patients who received a concomitant pelvic revascularization procedure, suggesting instead that such procedural adjuncts may actually increase risk for this complication.

Outcome analysis and risk factors for postoperative colonic ischaemia after aortic surgery

Purpose

Colonic ischaemia (CI) represents a serious complication after aortic surgery. This study aimed to analyse risk factors and outcome of patients suffering from postoperative CI.

Methods

Data of 1404 patients who underwent aortic surgery were retrospectively analysed regarding CI occurrence. Co-morbidities, procedural parameters, colon blood supply, procedure-related morbidity and mortality as well as survival during follow-up (FU) were compared with patients without CI using matched-pair analysis (1:3).

Results

Thirty-five patients (2.4%) with CI were identified. Cardiovascular, pulmonary and renal comorbidity were more common in CI patients. Operation time was longer (283 ± 22 vs. 188 ± 7 min, p < 0.0001) and blood loss was higher (2174 ± 396 vs. 1319 ± 108 ml, p = 0.0049) in the CI group. Patients with ruptured abdominal aortic aneurysm (AAA) showed a higher rate of CI compared to patients with intact AAA (5.4 vs. 1.9%, p = 0.0177). CI was predominantly diagnosed by endoscopy (26/35), generally within the first 4 postoperative days (20/35). Twenty-eight patients underwent surgery, all finalised with stoma creation. Postoperative bilateral occlusion and/or relevant stenosis of hypogastric arteries were more frequent in CI patients (57.8 vs. 20.8%, p = 0.0273). In-hospital mortality was increased in the CI group (26.7 vs. 2.9%, p < 0.0001). Survival was significantly reduced in CI patients (median: 28.2 months vs. 104.1 months, p < 0.0001).

Conclusion

CI after aortic surgery is associated with considerable perioperative sequelae and reduced survival. Especially in patients at risk, such as those with rAAA, complicated intraoperative course, severe cardiovascular morbidity and/or perioperative deterioration of the hypogastric perfusion, vigilant postoperative multimodal monitoring is required in order to initiate diagnosis and treatment.

Electronic supplementary material

The online version of this article (10.1007/s00423-020-01964-2) contains supplementary material, which is available to authorized users.

Pelvic radiation therapy as a potential risk factor for ischemic colitis complicating abdominal aortic reconstruction

A 78-year-old man with a 56-mm juxtarenal aneurysm and previous pelvic radiotherapy for prostate cancer (3 years earlier) who was disease free during follow-up received elective aortoaortic bypass suprarenal clamping through a transperitoneal approach. After the patient experienced initial abdominal pain and diarrhea, a computed tomography scan showed mild sigmoid inflammation, and the patient received conservative treatment. One month after discharge, the patient underwent urgent laparotomy and bowel and sigmoid resection for an enterocutaneous fistula. At 6-month follow-up, he has recovered, although a bowel stoma remains.

Total Endovascular Therapy of Abdominal Aortic Aneurysm, Peripheral Artery Disease, and Chronic Mesenteric Ischemia: A Challenging Case

We presented a challenging case of a patient diagnosed with abdominal aortic aneurysm (AAA), peripheral artery disease, and chronic mesenteric ischemia (CMI). Herein, we describe the treatment in this high-risk patient diagnosed with CMI who also had critical limb ischemia and his AAA had rapidly expanded. First we performed angioplasty and celiac arterial stenting. Afterwards, we proceeded to perform balloon angioplasty of the iliac arteries and chimney endovascular aneurysm repair (Ch-EVAR) preserving the inferior mesenteric artery (IMA). The patient was discharged three days later and his IMA remained patent eighteen months post-operation. A thorough pre-operative assessment is essential in such challenging cases. Minimally invasive procedures like endovascular therapy and the chimney technique extend the prognoses in high-risk patients.

Evolving Management of Distal Anastomotic Technical Issues During Open Aortic Aneurysm Repair

BACKGROUND

Thrombosis of the iliac anastomosis is an important complication of open aortic aneurysm repair. We evaluated our evolving management of this complication to an endovascular approach and compared it with open revision to the common femoral artery.

METHODS

Consecutive patients undergoing open aortic aneurysm repair from January 2009 through November 2016 at our institution were reviewed. Patients who developed iliac limb flow issues or thrombosis intraoperatively or within 48 hrs postoperatively were identified. Patients were grouped by management strategies of either 1) an endovascular approach including iliac angiography, thrombectomy if needed, and stenting or 2) open surgical revision of the iliac anastomosis with or without bypass to the common femoral artery. Demographics, comorbidities, operative variables, and outcomes were retrospectively analyzed between groups. Primary patency and mortality were assessed by Kaplan-Meier estimates.

RESULTS

There were 711 patients who underwent aortoiliac aneurysm repair during the study period. 43/711 patients (6.0%) developed early perioperative iliac limb flow issues including thrombosis. Twenty-nine patients (31 limbs) were managed by an endovascular approach, and 14 patients (15 limbs) were managed by open surgical revision. The mean age of the cohort was 69 years, and 27 patients (62.8%) were male. Preoperative creatinine and diabetes frequency were higher in patients managed by an endovascular approach, although no other differences existed between preoperative comorbidities. Thrombosis or limb flow issues presented intraoperatively more commonly in the open surgical group and in the first 24 hrs postoperatively in the endovascular group. All patients had complete restoration of outflow as a result of the rescue procedure. Transfusion requirements and crystalloid replacement were significantly higher in the open surgical group. Length of stay, perioperative complications, and mortality were similar between groups. Overall, 21/31 limbs in the endovascular group and 9/15 limbs in the open surgical group had postoperative imaging, with mean follow-up of 35.0 and 55.6 months, respectively. Only one patient in the cohort lost patency: an iliofemoral jump graft that presented with late infection after postoperative wound infection, requiring staged extra-anatomic bypass and explant at 12 months. Three-year primary patency was 100% for the endovascular group and 85.7% for the surgical group by Kaplan-Meier method (P = 0.32). Endovascular management became our institution's primary salvage approach during the study. Whereas 8/15 limbs (53.3%) were managed by an endovascular approach from 2009-2011, 23/31 (74%) were managed by iliac stenting from 2012-2016.

CONCLUSIONS

Endovascular management of iliac limb flow issues or thrombosis after open aneurysm repair is potentially a viable alternative to open surgical revision in the early postoperative period.

Inferior mesenteric artery replantation does not decrease the risk of ischemic colitis after open infrarenal abdominal aortic aneurysm repair

BACKGROUND

Ischemic colitis after an open abdominal aortic aneurysm (AAA) repair remains a serious complication with a nationally reported rate of 1% to 6% in elective cases and up to 60% after an aneurysmal rupture. To prevent this serious complication, inferior mesenteric artery (IMA) replantation is performed at the discretion of the surgeon based on his or her intraoperative findings, despite the lack of clear evidence to support this practice. The purpose of this study was to determine whether replantation of the IMA reduces the risk of ischemic colitis and improves the overall outcome of AAA repair.

METHODS

Patients who underwent open infrarenal AAA repair were identified in the multicenter American College of Surgeons National Surgical Quality Improvement Program Targeted AAA Database from 2012 to 2015. Emergency cases, patients with chronically occluded IMAs, ruptured aneurysms with evidence of hypotension, and patients requiring visceral revascularization were excluded. The remaining elective cases were divided into two groups: those with IMA replantation (IMA-R) and those with IMA ligation. We measured the 30-day outcomes including mortality, morbidity, and perioperative outcomes. A multivariable logistic regression model was used for data analysis, adjusting for clinically relevant covariates.

RESULTS

We identified 2397 patients who underwent AAA repair between 2012 and 2015, of which 135 patients (5.6%) had ischemic colitis. After applying the appropriate exclusion criteria, there were 672 patients who were included in our study. This cohort was divided into two groups: 35 patients with IMA-R and 637 patients with IMA ligation. There were no major differences in preoperative comorbidities between the two groups. IMA-R was associated with increased mean operative time (319.7 ± 117.8 minutes vs 242.4 ± 109.3 minutes; P < .001). Examination of 30-day outcomes revealed patients with IMA-R had a higher rate of return to the operating room (20.0% vs 7.2%; P = .006), a higher rate of wound complications (17.1% vs 3.0%; P = .001), and a higher incidence of ischemic colitis (8.6% vs 2.4%; P = .027). There were no significant differences in mortality, pulmonary complications, or renal complications between the two groups. In multivariable analysis, IMA-R was a significant predictor of ischemic colitis and wound complications.

CONCLUSIONS

These data suggest that IMA-R is not associated with protection from ischemic colitis after open AAA repair. The role of IMA-R remains to be identified.

The Value of Sigmoidoscopy to Detect Colonic Ischaemia After Ruptured Abdominal Aortic Aneurysm Repair

OBJECTIVES

Diagnosing colonic ischaemia (CI) after ruptured abdominal aortic aneurysm (RAAA) repair is challenging. This study determined the diagnostic value of sigmoidoscopy in patients suspected of CI after RAAA repair.

METHODS

This was a retrospective multicentre cohort study. Patients who underwent RAAA repair in three hospitals in Amsterdam, the Netherlands, between 2004 and 2011 (AJAX cohort) were included. Sigmoidoscopies were carried out based on clinical judgment. Endoscopy results were classified as "no ischaemia," "mild CI," or "moderate to severe CI." The surgical diagnosis was classified as "transmural" or "no transmural" CI. The value of sigmoidoscopy was assessed with calculation of positive and negative predictive values (PPV, NPV) with 95% CI for transmural CI. Logistic regression analysis was used to express the association of risk factors with CI as adjusted OR.

RESULTS

Transmural CI was diagnosed in 23 of 351 patients (6.6%). Thirteen of sixteen patients (81%) who underwent direct laparotomy for high suspicion of CI indeed had transmural CI. Forty-six patients (13%) underwent sigmoidoscopy. The prevalence of transmural CI was 22% (10/46; 95% CI 12-36%) in these patients. The PPV for transmural CI of "moderate to severe CI" on sigmoidoscopy was 73% (8/11; 95% CI 43-90%). The PPV of "mild CI" on sigmoidoscopy was 11% (2/19; 95% CI 2.9-31%). The NPV of "no ischaemia" on sigmoidoscopy was 100% (95% CI 78-100%). Cardiac comorbidity (OR 3.1, 95% CI 1.19-7.97), low first haemoglobin (OR 0.6, 95% CI 0.47-0.87), and high vasopressor administration (OR 9.4, 95% CI 1.99-44.46) were independently associated with CI.

CONCLUSIONS

Sigmoidoscopy increases the likelihood of correctly identifying the presence or absence of transmural CI, especially in patients with a moderate clinical suspicion for CI after RAAA repair.

Systematic review and meta-analysis of the risk of bowel ischemia after ruptured abdominal aortic aneurysm repair

OBJECTIVE

Outcomes after repair of ruptured abdominal aortic aneurysm (RAAA) have improved in the last decade. It is unknown whether this has resulted in a reduction of postoperative bowel ischemia (BI). The primary objective was to determine BI prevalence after RAAA repair. Secondary objectives were to determine its major sequelae and differences between open repair (OR) and endovascular aneurysm repair (EVAR).

METHODS

This systematic review (PROSPERO CRD42017055920) followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. MEDLINE and Embase were searched for studies published from 2005 until 2018. The methodologic quality of observational studies was assessed with the Methodological Index for Non-Randomized Studies (MINORS) tool. The quality of the randomized controlled trials (RCTs) was assessed with the Cochrane Collaboration's tool for assessing risk of bias. BI prevalence and rates of BI as cause of death, reoperation, and bowel resection were estimated with meta-analyses with a random-effects model. Differences between OR and EVAR were estimated with pooled risk ratios with 95% confidence intervals (CIs). Changes over time were assessed with Spearman rank test (ρ). Publication bias was assessed with a funnel plot analysis.

RESULTS

A total of 101 studies with 52,670 patients were included; 72 studies were retrospective cohort studies, 14 studies were prospective cohort studies, 12 studies were retrospective administrative database studies, and 3 studies were RCTs. The overall methodologic quality of the RCTs was high, but that of observational studies was low. The pooled prevalence of BI ranged from of 0.08 (95% CI, 0.07-0.09) in database studies to 0.10 (95% CI, 0.08-0.12) in cohort studies. The risk of BI was higher after OR than after EVAR (risk ratio, 1.79; 95% CI, 1.25-2.57). The pooled rate of BI as cause of death was 0.04 (95% CI, 0.03-0.05), and that of BI as cause of reoperation and bowel resection ranged between 0.05 and 0.07. BI prevalence did not change over time (ρ, -0.01; P = .93). The funnel plot analysis was highly suggestive of publication bias.

CONCLUSIONS

The prevalence of clinically relevant BI after RAAA repair is approximately 10%. Approximately 5% of patients undergoing RAAA repair suffer from severe consequences of BI. BI is less prevalent after EVAR than after OR.