Perioperative predictors of colonic ischemia after ruptured abdominal aortic aneurysm

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

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.

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.

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.

Value of Routine Flexible Sigmoidoscopy and Potential Predictive Factors for Colonic Ischemia after Open Ruptured Abdominal Aortic Aneurysm Repair

Background and Objectives: colonic ischemia (CI) after ruptured abdominal aortic aneurysm (rAAA) repair is associated with increased morbidity and mortality. CI may be detected by using flexible sigmoidoscopy, but routine use of flexible sigmoidoscopy after rAAA is not clearly proven. The objective of this study was to evaluate the efficacy of routine flexible sigmoidoscopy in detecting CI after rAAA repair, and to identify potential hemodynamic, biochemical, and clinical variables that can predict the development of CI in the patients who underwent rAAA surgery. Materials and Methods: we retrospectively included all rAAA cases treated in Viborg hospital from 1 April 2014 until 31 August 2017, recorded the findings on flexible sigmoidoscopy, and the incidence of CI. We collected specific hemodynamic, biochemical, and clinical variables, measured pre- and perioperatively, and the first three postoperative days. The association between CI and possible predictors was analyzed in a logistic regression model. Results: a total of 80 patients underwent open rAAA repair during the study period. Flexible sigmoidoscopy was performed in 58 of 80 patients (73.5%) who survived at least 24 h after open rAAA surgery. Perioperative variables lowest arterial pH (p = 0.02) and types of operations—aortobifemoral bypass vs. straight graft (p = 0.04) showed statistically significant differences between CI groups. The analysis of the postoperative variables showed statistically significant difference in highest lactate on postoperative day 1 (p = 0.01), and lowest hemoglobin on postoperative day 2 (p = 0.04) comparing CI groups. Logistic regression model revealed that postoperative hemoglobin and lactate turned out to be independent risk factors for the development of CI (respectively OR = 0.44 (95% CI = 0.29–0.67) and OR = 1.91 (95% CI = 1.2–3.05)). Conclusions: flexible sigmoidoscopy can identify patients being at higher risk of mortality after open rAAA repair. The postoperative lactate and hemoglobin were found to be independent risk factors for the development of CI after open rAAA repair. Further larger studies are warranted to demonstrate these findings.

Surgical Complications after Open Abdominal Aortic Aneurysm Repair: Intestinal Ischemia, Buttock Claudication and Sexual Dysfunction

While surgical treatment for abdominal aortic aneurysm (AAA) is a standard operation, prevention of complication is important. Intestinal ischemia of the sigmoid colon and/or rectum after AAA surgery is severe and has a high mortality rate although occurrence frequency is low. The most important thing to prevent is the preoperative and intraoperative evaluation of the left hemicolon and rectal circulation. Measurement of inferior mesenteric artery stump pressure is also useful. From the viewpoint of prevention of buttock claudication, it is desirable that internal iliac artery (IIA) blood flow is preserved, but aggressive IIA reconstruction adaptation is considered to be low. For erectile function, it is important that the antegrade blood flow from the IIA to the internal pudendal artery on at least one side is preserved or reconstructed. To prevent retrograde ejaculation, it is important to preserve the superior hypogastric plexus and one side of the lumbar splanchnic nerve, and the hypogastric nerve. Understanding and mastering local anatomy and pathophysiology is important in preventing complications, and we must also remember that we always keep watchful surgical operations in mind in order to prevent tissue damage. (This is a translation of Jpn J Vasc Surg 2019; 28: 99-103.).

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.

Accuracy of Routine Endoscopy Diagnosing Colonic Ischaemia After Abdominal Aortic Aneurysm Repair: A Meta-analysis

BACKGROUND

Colonic ischaemia (CI) is a devastating complication after abdominal aortic aneurysm (AAA) surgery. The aim of this review was to evaluate the diagnostic test accuracy of routine endoscopy in diagnosing CI after treatment for elective and acute AAA.

PATIENTS AND METHODS

The Pubmed and Embase database searches resulted in 1188 articles. Prospective studies describing routine post-operative colonoscopy or sigmoidoscopy after elective or emergency AAA repair were included. The study quality was assessed with the QUADAS-2 tool. Sensitivity and specificity forest plots were drawn. Diagnostic odds ratios were calculated by a random effect model.

RESULTS

Twelve articles were included consisting of 718 AAA patients of whom 44% were treated electively, 56% ruptured and, 6% by endovascular repair. Of all patients, 20.8% were identified with CI (all grades), and 6.5% of patients had Grade 3 CI. The pooled diagnostic odds ratio for all grades of CI on endoscopy was 26.60 (95% CI 8.86-79.88). The sensitivity and specificity of endoscopy for detection of Grade 3 CI after AAA repair was 0.52 (95% CI, 0.31-0.73) and 0.97 (95% CI 0.95-0.99) respectively. The positive post-test probability is up to 60% in all kinds of AAA patients and 68% in ruptured AAA patients.

CONCLUSION

Routine endoscopy is highly accurate for ruling out CI after AAA repair. Clinicians should be aware that endoscopy is less accurate in diagnosing the presence of the clinically relevant transmural CI. Endoscopy is a safe diagnostic test to use routinely as none of the studies reported adverse events.

An 18-cm unruptured abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a significant source of morbidity and ranked by the Centers for Disease Control and Prevention as the 15^th leading cause of death among adults aged 60 to 64 years. Size confers the largest risk factor for aneurysm rupture, with aneurysms >6 cm having an annual rupture risk of 14.1%. We present the case of a 60-year-old man found on ultrasound imaging at a health fair screening to have a 15-cm AAA. Follow-up computed tomography angiography revealed an 18-cm × 10-cm unruptured, infrarenal, fusiform AAA. Giant AAAs, defined as >11 cm, are rarely described in the literature. Our patient underwent successful transperitoneal AAA repair with inferior mesenteric artery reimplantation and was discharged home on operative day 6. We believe this case represents one of the largest unruptured AAAs in the literature and demonstrates the feasible approach for successful repair.

The Incidence of Ischemic Colitis after Repair of Ruptured Abdominal Aortic Aneurysms Is Decreasing in the Endovascular Era

BACKGROUND

Ischemic colitis (IC) is a well-described complication of ruptured abdominal aortic aneurysms (rAAAs). The purpose of this study was to compare the incidence of IC in patients with rAAA undergoing open repair (OR) versus endovascular aneurysm repair (EVAR) at a single institution. In addition, we analyzed the incidence of IC before and after the implementation of a formal rupture AAA protocol (rEVAR protocol).

METHODS

A retrospective analysis of prospectively collected data on all patients presenting with rAAA to our institution between January 2002 and October 2013 was performed. Variables were analyzed for association with IC. Comparisons were made using Pearson's chi-squared test or Fisher's exact test for categorical variables, Student's t-test for continuous variables, and logistic regression for multivariate analysis. Significance was set at P < 0.05.

RESULTS

Three hundred three patients with rAAA presented over the 10-year study period. One hundred ninety-one patients underwent OR and 89 patients underwent endovascular repair. Twenty-three patients died either in the emergency department, en route to the operating room, or after choosing comfort care. Predictive factors of IC included estimated blood loss, corresponding need for resuscitation, and duration of procedure. Of patients who underwent OR, the rate of IC was 21% (40/191). This was significantly higher than patients who underwent EVAR, 7% (6/89), P < 0.05. The type of intervention did not influence 30-day mortality in patients with IC. However, only 17% (1/6) of patients who had IC following EVAR required colectomy versus 48% (19/40) of patients with IC following OR (P = 0.21). Implementation of our formal rEVAR protocol decreased the incidence of IC significantly from 37.1% (36/97) to 6.4% (10/157), P < 0.001.

CONCLUSIONS

The incidence of IC has decreased significantly in the endovascular era but continues to portend a poor prognosis. Implementation of a formal, multidisciplinary rEVAR protocol in our institution decreased the incidence of IC.

Giant Infrarenal Aortic Aneurysm Rupture Preceded by Left Lower Limb Motor Deficit

This report presents the surgical repair and postsurgical outcomes following a ruptured infrarenal aortic aneurysm with a maximum transverse diameter of 20 cm. Its association with acute lower limb motor deficit is rare. Open surgery of giant abdominal aortic aneurysms is often the only available treatment, favored over an endovascular approach in the presence of increased aneurysm size with dislodged abdominal organs, adhesions, and short and angled proximal infrarenal aortic neck, presenting significant additional surgical and anesthesiological challenges.

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

BACKGROUND

Bowel ischemia is a rare but devastating complication after abdominal aortic aneurysm (AAA) repair. Its rarity has prohibited extensive risk-factor analysis, particularly since the widespread adoption of endovascular AAA repair (EVAR); therefore, this study assessed the incidence of postoperative bowel ischemia after AAA repair in the endovascular era and identified risk factors for its occurrence.

METHODS

All patients undergoing intact or ruptured AAA repair in the Vascular Study Group of New England (VSGNE) between January 2003 and November 2014 were included. Patients with and without postoperative bowel ischemia were compared and stratified by indication (intact and ruptured) and treatment approach (open repair and EVAR). Criteria for diagnosis were endoscopic or clinical evidence of ischemia, including bloody stools, in patients who died before diagnostic procedures were performed. Independent predictors of postoperative bowel ischemia were established using multivariable logistic regression analysis.

RESULTS

Included were 7312 patients, with 6668 intact (67.0% EVAR) and 644 ruptured AAA repairs (31.5% EVAR). The incidence of bowel ischemia after intact repair was 1.6% (open repair, 3.6%; EVAR, 0.6%) and 15.2% after ruptured repair (open repair, 19.3%; EVAR, 6.4%). Ruptured AAA was the most important determinant of postoperative bowel ischemia (odds ratio [OR], 6.4, 95% confidence interval [CI], 4.5-9.0), followed by open repair (OR, 2.9; 95% CI, 1.8-4.7). Additional predictive patient factors were advanced age (OR, 1.4 per 10 years; 95% CI, 1.1-1.7), female gender (OR, 1.6; 95% CI, 1.1-2.2), hypertension (OR, 1.8; 95% CI, 1.1-3.0), heart failure (OR, 1.8; 95% CI, 1.2-2.8), and current smoking (OR, 1.5; 95% CI, 1.1-2.1). Other risk factors included unilateral interruption of the hypogastric artery (OR, 1.7; 95% CI, 1.0-2.8), prolonged operative time (OR, 1.2 per 60-minute increase; 95% CI, 1.1-1.3), blood loss >1 L (OR, 2.0; 95% CI, 1.3-3.0), and a distal anastomosis to the femoral artery (OR, 1.7; 95% CI, 1.1-2.7). Bowel ischemia patients had a significantly higher perioperative mortality after intact (open repair: 20.5% vs 1.9%; P < .001; EVAR: 34.6% vs 0.9%; P < .001) as well as after ruptured AAA repair (open repair: 48.2% vs 25.6%; P < .001; EVAR: 30.8% vs 21.1%; P < .001).

CONCLUSIONS

This study underlines that although bowel ischemia after AAA repair is rare, the associated outcomes are very poor. The cause of postoperative bowel ischemia is multifactorial and can be attributed to patient factors and operative characteristics. These data should be considered during preoperative risk assessment and for optimization of both the patient and the procedure in an effort to reduce the risk of postoperative bowel ischemia.

Risk factors for ischaemic colitis after surgery for abdominal aortic aneurysm: a systematic review and observational meta-analysis

BACKGROUND

Ischaemic colitis is an infrequent but serious complication following repair of abdominal aortic aneurysm (AAA), with high mortality rates. This systematic review set out to identify risk factors for the development of ischaemic colitis after AAA surgery.

METHODS

A systematic search of the MEDLINE, EMBASE and CINAHL databases was performed. This search was limited to studies published in the English language after 1990. Abstracts were screened by two authors. Eligible studies were obtained as full text for further examination. Data was extracted by two authors, and any disputes were resolved via consensus. Extracted data was pooled using Mantel-Haenszel random effects models. Bias was assessed using two Cochrane-approved tools. Effect sizes are expressed as relative risk ratios alongside the 95 % confidence interval. Statistical significance was defined at the level of p < 0.05.

RESULTS

From 388 studies identified in the initial search, 33 articles were included in the final synthesis and analysis. Risk factors were grouped into patient (female gender, disease severity) and operative factors (peri-procedural hypotension, operative modality). The risk of ischaemic colitis was significantly higher when undergoing emergency repair versus elective (risk ratio (RR) 7.36, 3.08 to 17.58, p < 0.001). Endovascular repair reduced the likelihood of ischaemic colitis (RR 0.22, 0.12 to 0.39, p < 0.001).

DISCUSSION

The quality of published evidence on this subject is poor with many retrospective datasets and inconsistent reporting across studies. Despite this, emergency presentation and open repair should prompt close monitoring for the development of IC.

Open Repair of Ruptured Huge Aorto-Iliac Aneurysm: Warning of Colon Ischemia

A giant abdominal aortic aneurysm (AAA) renders surgical treatment much more difficult by deforming the proximal infrarenal aortic neck (shortened length and disturbed angulation), by altering the iliac arteries (marked tortuosity and aneurysmal dilatation), and by displacing abdominal organs. Because the retroperitoneal rupture of giant AAA makes the mesentery more elongated and deformed, compromising its blood flow and thus increasing the risk of mesenteric ischemia such as colon ischemia. We describe here the surgical repair of a large infrarenal AAA with a ruptured huge left common iliac artery aneurysm of 13.5 cm in diameter, accompanied by colostomy due to colon ischemia which occurred during the operation. We discuss the pathophysiology and preventive strategy of colon ischemia during ruptured giant AAA repair.

Ischemic colitis: the ABCs of diagnosis and surgical management

Ischemic colitis (IC) is a rare condition. As ischemia is often transient and clinical symptoms are reversible, its exact incidence is unknown. In current clinical practice, two types of IC are described according to the severity: severe IC, with transmural colonic ischemia and/or multi-organ failure (MOF), and mild IC, without MOF and spontaneous favourable evolution in most cases. Two clinical contexts are encountered: spontaneous IC (SIC) and postoperative IC (POIC), mainly after aortic surgery. As there is no specific clinico-biologic symptom of IC, emergent CT-scan and rectosigmoidoscopy are required for diagnosis confirmation, surgical decision and prognosis analysis. IC surgical treatment is not consensual but can be standardized according to organ function and the degree of ischemia: surgical treatment in case of colonic necrosis with deep ischemia and/or MOF; observation for superficial ischemia without organ dysfunction; systematic medical care. Surgery is required in 20% of cases, and consists in extended colectomy without continuity restoration and prophylactic cholecystectomy. Continuity restoration is feasible in one third of survivors, who are exposed to a high risk of severe cardiovascular events.

Reliability of selective surveillance colonoscopy in the early diagnosis of colonic ischemia after successful ruptured abdominal aortic aneurysm repair

PURPOSE

To evaluate the reliability of selective surveillance colonoscopy based on 6 specific perioperative risk factors in the early diagnosis of colonic ischemia (CI) after successful ruptured abdominal aortic aneurysm (rAAA) repair.

PATIENTS AND METHODS

From 1999 to 2005, 62 consecutive patients underwent rAAA repair. In 59 of them, routine aggressive surveillance colonoscopy was offered every 12 hours within the first 48 hours, and CI was graded consistently. Patients with stage I or stage II CI were treated conservatively and were followed up with repeat colonoscopy, whereas patients with stage III CI underwent immediate laparotomy and colectomy. In parallel, 6 specific perioperative risk factors (PRFs) were retrospectively analyzed.

RESULTS

Overall mortality was 33.9%. Nineteen patients (32.2%) developed CI and 12 (63.2%) of them survived. Thirteen (22%) had grade III CI and among these 6 survived. In patients with CI the mortality rate was 36.2%. Patients with less than 3 PRFs had no CI whereas all instances of CI could be diagnosed if colonoscopy was offered selectively in patients with more than 3 PRFs. The positive predictive value of CI increased with the number of PRFs. Patients with 5 or 6 PRFs were about 101 times more likely to develop CI compared with patients with 0 to 4 PRFs (P<.001).

CONCLUSION

Our study showed that CI is a frequent complication after successful rAAA repair and could reliably be early diagnosed if surveillance colonoscopy was offered selectively in patients with more than three PRFs.

Effects of thoracic and hiatal clamping in repair of ruptured abdominal aortic aneurysms

The purpose of this study was to determine the effects of hiatal and thoracic clamping on postoperative outcome and morbidity and factors affecting mortality and morbidity. The records of 102 patients who had undergone ruptured abdominal aortic aneurysm repair between 1993 and 2005 were evaluated retrospectively. Hiatal clamping and thoracic clamping were performed in 72 patients and 30 patients, respectively. Postoperative complications and survival were evaluated comparatively between the two groups by univariate and multivariate statistical analyses. Overall mortality and hospital mortality rates were 63 (61.8%) and 24 (23.5%) patients, respectively; and there was no difference between the two groups. Postoperative respiratory complications, gastrointestinal complications, and blood requirement were higher in the thoracic clamping group. Preoperative shock and renal ischemia time (>30 min) were found to be significant predictors of hospital mortality. Postoperative renal failure was the only independent postoperative predictor of mortality. In the follow-up period, cardiac event was an independent predictor of late mortality. If hospital mortalities were excluded, 5-year and 10-year cumulative survivals were 57.82 +/- 5.85% and 38.16 +/- 6.97%, respectively. Cross-clamp level did not have a significant effect on long-term survival. Although both thoracic and hiatal clamping had no effect on mortality, postoperative respiratory complications, blood requirement, and intestinal ischemia were more pronounced in patients operated with thoracic clamping. Hiatal clamping is preferable for a safe postoperative period.

Incidence of colonic ischemia after repair of ruptured abdominal aortic aneurysm with endograft

BACKGROUND

Colonic ischemia after open repair of ruptured abdominal aortic aneurysm (rAAA) has been reported to be as high as 42% and is associated with high mortality rates when transmural necrosis is involved. With the evolution of endovascular aortic repair (EVAR) devices, some centers now primarily use this technique for rAAA. The objective of this study was to determine the incidence of colonic ischemia after EVAR of rAAA.

STUDY DESIGN

All patients who underwent EVAR of rAAA from January 2002 to January 2006 were included in this review. All flexible sigmoidoscopies were performed within 48 hours, ischemia was graded consistently, and treatment was initiated per protocol based on grade of ischemia. Patients with grades I and II ischemia were followed up with medical management and in some cases, repeat colonoscopy. All patients with grade III ischemia underwent bowel resection.

RESULTS

Forty-four patients underwent EVAR of rAAA during the study period. Operative mortality was 11%. Sigmoidoscopy was performed in 36 of 39 patients who survived longer than 24 hours. Bowel ischemia was documented in 8 of the 36 patients (23%). Of these, five had grade I or grade II ischemia at both initial and repeat endoscopy, so these patients did not progress to resection. Three patients underwent exploratory laparotomy with bowel resection because of grade III ischemia; one of these procedures was performed for worsening ischemia discovered at repeat colonoscopy.

CONCLUSIONS

This study demonstrated that the overall incidence of colonic ischemia (23%) after EVAR of rAAA is less than that reported for the open repair. We would continue to recommend mandatory flexible sigmoidoscopy for these patients.

Abdominal aortic aneurysm repair and colonic infarction: a risk factor appraisal

OBJECTIVE

Colonic infarction is a recognized complication of abdominal aortic aneurysm (AAA) surgery. The clinical difficulty in establishing the diagnosis combined with the patient's poor physiological status is usually associated with a fatal outcome. We assessed our experience with this problem to identify a possible risk factor profile for these patients.

METHOD

Patients records were identified from the operative logs, intensive care unit, Hospital Inpatient Enquiry system and vascular unit databases over a 6-year period.

RESULTS

A total of 405 patients underwent AAA repair during this period; 140 as emergency ruptures. Nine patients were identified from the databases with known colonic infarction (2.2%). One was a woman. The mean age was 70 years. Seven patients had emergency ruptures (5%). Twenty independent risk factors were analysed using univariate and multivariate logistic regression models. Significant risk factors identified by using a multivariate analysis included the nature of the presenting patient, preoperative hypotension, prolonged cross-clamp time, intra-operative ischaemia and postoperative acidosis. Confirmatory diagnosis was made by colonoscopy in eight patients. One patient survived following the salvage surgery. The mean duration of survival was 10.5 days. The overall mortality was 89% of patients.

CONCLUSION

In our unit infrarenal AAA repair has a 2.2% rate of colonic infarction. A definitive diagnosis is best made by colonoscopy. A risk factor profile for the development of colonic infarction may be constructed on the basis of specific clinical parameters. Earlier intervention on the basis of this profile may ultimately reduce the current excessive mortality.

Replanting the inferior mesentery artery during infrarenal aortic aneurysm repair: influence on postoperative colon ischemia

BACKGROUND

Replanting the inferior mesentery artery (IMA) to prevent ischemic colitis (IC) has been discussed for many years; yet, to our knowledge, no prospective studies have been conducted to compare the incidence of histologically proven IC in patients with and without IMA revascularization. The aim of this prospective study, with histologic evaluation of the sigmoid colon mucosa, was to assess the influence of replanting the IMA on IC and mortality.

METHODS

From January 1999 to December 2003, 160 consecutive patients who were operated on for a symptomatic (n = 21) or asymptomatic (n = 139) infrarenal aortic aneurysm were prospectively assessed and randomly assigned either to replanting or ligating the IMA. Sigmoidoscopy with biopsy was performed on day 4 or 5 after surgery; an autopsy was performed on patients not surviving to day 5 after surgery. All patients gave written informed consent.

RESULTS

Of the 160 randomized patients, 128 had a confirmed patent IMA and formed the basis of this study. Their age was 70 +/- 8 years (men, 70 +/- 8 years; women, 73 +/- 7 years). The IMA was replanted in 67 patients (52%) and ligated in 61 (48%) intraoperatively. IC developed in six patients with a replanted IMA and in 10 with a ligated IMA (relative risk [RR], 0.55; 95% confidence interval [CI], 0.21 to 1.41; chi2 = 1.62; P = .203). Blood loss in the two cohorts did not differ significantly (P = .788); however, patients with IC had a significantly higher blood loss compared with the cohort without IC (P = .012) and were older (P = .017). Age, sex distribution, clamping time, the use of tube or bifurcated grafts, and intraoperative hypotension did not differ between patients with ligated or replanted IMA.

CONCLUSION

Although replanting the IMA did not confer a statistically significant reduction of perioperative morbidity or mortality in this study, it appears that older patients and patients with increased intraoperative blood loss might benefit from IMA replantation, because this maneuver does not increase perioperative morbidity or substantially increase operation time.

Outcome of aggressive surveillance colonoscopy in ruptured abdominal aortic aneurysm

PURPOSE

Emergent repair of ruptured abdominal aortic aneurysms (rAAAs) is associated with high perioperative morbidity and mortality. One of the significant complications of this surgery is bowel ischemia. Reports detail mortality as high as 80% when this condition is realized. The objective of this project was to determine both the incidence and the effect of mandatory postoperative colonoscopy on outcome of colon ischemia after rAAA.

METHODS

From July 1995 to September 2002 all patients with an rAAA who underwent emergent aortic reconstruction were included in this review. All colonoscopies were performed within 48 hours, ischemia was graded consistently, and treatment was initiated per protocol based on grade of ischemia. Patients with grades I and II ischemia were followed up with medical management and repeat colonoscopy. All patients with grade III ischemia underwent bowel resection. Preoperative, intraoperative, and postoperative variables were collected to assess possible independent risk factors for and predictors of bowel ischemia.

RESULTS

Eighty-eight patients underwent emergent aortic reconstruction because of rAAA in the study period. Their mean age was 73 years, and 64 patients (72%) were men. Operative mortality was 42%. Eighteen percent of patients died within 24 hours, and 24% died between 1 and 30 days after surgery. Colonoscopy was performed in 62 of 72 patients who survived more than 24 hours. Bowel ischemia was documented in 26 of the 72 patients (36%). Of these, 16 patients had grade I or grade II ischemia at both initial and repeat endoscopy. Nine patients underwent exploratory laparotomy with bowel resection because of grade III ischemia; two procedures were performed because of worsening ischemia discovered at repeat colonoscopy. In patients with colonoscopic findings of bowel ischemia the mortality rate was 50% (13 of 26 patients). In those with grade III necrosis who underwent resection the mortality rate was 55%. Elevated lactate levels, immature white blood cells, and increased fluid sequestration were all variables associated with the occurrence of colon ischemia.

CONCLUSIONS

Bowel ischemia is a frequent postoperative complication (42%) of repaired rAAA. Performing mandatory surveillance colonoscopy in these patients may be associated with a decrease in overall mortality and improved survival in patients with transmural bowel necrosis with no comorbid condition.

Non-occlusive mesenteric ischaemia: a common disorder in gastroenterology and intensive care

Non-occlusive mesenteric ischaemia is characterized by gastrointestinal ischaemia with normal vessels. In gastroenterology it is recognized as rare disease occasionally causing acute bowel infarction or ischaemic colitis. From intensive care literature this disorder is recognized as an early phenomenon during circulatory stress. This early mucosal ischaemia then leads to increased permeability, bacterial translocation, and further mucosal hypoperfusion. The damage is produced mainly during reperfusion following ischaemia with fresh inflow of oxygen and outflow of waste products into the systemic circulation. The mechanisms underlying non-occlusive mesenteric ischaemia include macrovascular vasoconstriction, hypoperfusion of the tips of the villi and shunting. It is very common in critically ill and perioperative patients, but also occurs in pancreatitis, renal failure and sepsis. Treatment options include aggressive fluid resuscitation and careful choice of vasoactive drugs. Control of reperfusion damage and new endothelin-antagonists are potentially useful new treatment options.

Gastrointestinal Complications after Ruptured Aortic Aneurysm Repair

Gastrointestinal complications after ruptured aortic abdominal aneurysm (AAA) repair are not well defined and are limited to descriptions of ischemic colitis. We sought to delineate risk factors predicting gastrointestinal complications after ruptured AAA repair. Data from 100 consecutive patients after ruptured AAA repair between July 1980 and June 2000 were gathered for multiple preoperative, intraoperative, and postoperative factors. These variables were analyzed relative to postoperative gastrointestinal complications and resulting mortality. Overall mortality was 48 per cent. Gastrointestinal complications were encountered 29 times in 27 patients of 100 total patients (27%). Complications included prolonged adynamic ileus (three), acute pancreatitis (four) and cholecystitis (two), perforated duodenal ulcer (one), bowel obstruction (three), antibiotic-associated colitis (six), ischemic colitis (three), bowel infarction (four), and liver failure (three). Comparison of patients with and without gastrointestinal complications showed no predictive preoperative or intraoperative variables. Gastrointestinal complications are common in ruptured aortic aneurysm repair and carry increased mortality and morbidity. Surgeons must maintain a high level of suspicion to anticipate possible gastrointestinal complications.

Early abdominal closure with mesh reduces multiple organ failure after ruptured abdominal aortic aneurysm repair: guidelines from a 10-year case-control study

OBJECTIVE

The objectives of this study were the comparison of patients who needed mesh closure of the abdomen with patients who underwent standard abdominal closure after ruptured abdominal aortic aneurysm repair and the determination of the impact of timing of mesh closure on multiple organ failure (MOF) and mortality.

METHODS

We performed a case-control study of patients who needed mesh-based abdominal closure (n = 45) as compared with patients who underwent primary closure (n = 90) after ruptured abdominal aortic aneurysm repair.

RESULTS

Before surgery, the patients who needed mesh abdominal closure had more blood loss (8 g versus 12 g of hemoglobin; P <.05), had prolonged hypotension (18 minutes versus 3 minutes; P <.01), and more frequently needed cardiopulmonary resuscitation (31% versus 2%; P <.01) than did the patients who underwent primary closure. During surgery, the patients who needed mesh closure also had more severe acidosis (base deficit, 14 versus 7; P <.01), had profound hypothermia (32 degrees C versus 35 degrees C; P <.01), and needed more fluid resuscitation (4.0 L/h versus 2.7 L/h; P <.01). With this adverse clinical profile, the patients who needed mesh closure had a higher mortality rate than did the patients who underwent primary closure (56% versus 9%; P <.01). However, the patients who underwent mesh closure at the initial operation (n = 35) had lower MOF scores (P <.05), a lower mortality rate (51% versus 70%), and were less likely to die from MOF (11% versus 70%; P <.05) than the patients who underwent mesh closure after a second operation in the postoperative period for abdominal compartment syndrome (n = 10).

CONCLUSION

This study reports the largest experience of mesh-based abdominal closure after ruptured abdominal aortic aneurysm repair and defines clinical predictors for patients who need to undergo this technique. Recognition of these predictors and initial use of mesh closure minimize abdominal compartment syndrome and reduce the rate of mortality as the result of MOF.

Ischaemia/reperfusion contributes to colonic injury following experimental aortic surgery

OBJECTIVES

ischaemia of the colon is an important complication of abdominal aortic aneurysm (AAA) repair. The aim of this animal study was to investigate the effect of sequential ischaemia and reperfusion on sigmoid mucosal pO2 and its association with local ET-1 release.

MATERIAL AND METHODS

twelve pigs underwent colonic ischaemia followed by complete reperfusion. Six other animals were sham controls. A Clark-type microcatheter was used for continuous mucosal pO2 measurements. Serial systemic and inferior mesenteric vein blood samples were obtained for determination of ET-1 concentration. Neutrophil extravasation was assessed by tissue myeloperoxidase (MPO) activity.

RESULTS

arterial occlusion was associated with a gradual decrease of mucosal pO2 and local release of ET-1. After restoration of blood flow, mucosal pO2 returned to near baseline values, whereas ET-1 reached its maximum concentration during the reperfusion period. MPO activity was significantly increased.

CONCLUSIONS

colonic ischaemia and reperfusion causes neutrophil extravasation and local ET-1.

pHi monitoring of the sigmoid colon after aortoiliac surgery. A five-year prospective study

OBJECTIVES

to determine whether sigmoid-pHi diagnose colon ischaemia after aortoiliac surgery?

DESIGN

single-centre, non-randomised, prospective study.

PATIENTS AND METHODS

of 83 patients operated on between 1994 and 1998, 41 with risk factors for the development of colon ischaemia were monitored peri- and/or postoperatively with sigmoid-pHi. Peri-operative mortality was 26% (8/31) after operation for a ruptured abdominal aortic aneurysm (AAA), nil after operation for non-ruptured AAA. Thirty-five postoperative colonoscopies were performed. All non-survivors were examined post-mortem.

RESULTS

of six patients developing colon ischaemia after emergency operations (five for ruptured AAA) all had pHi-values <7.1 for 16-80 h. In two patients with transmural gangrene, and who had pHi-values below 6.6, pHi-monitoring permitted early diagnosis, colectomy and recovery. Three patients with mucosal gangrene were treated conservatively and recovered. Nine patients without ischaemic lesions had pHi-values <7.1, during 1-5 h, without adverse outcome. Bilateral ligation of the internal iliac arteries increased the risk of colon ischaemia (p<0.0001).

CONCLUSIONS

pHi-monitoring was diagnostic for colon ischaemia. Mucosal and transmural gangrene were distinguished. The importance of the internal iliac circulation was demonstrated. The low mortality rate, and the fact that no patient died from bowel ischaemia, suggests that sigmoid pHi-monitoring may improve survival after ruptured AAA.

The cost-effectiveness of repairing ruptured abdominal aortic aneurysms

BACKGROUND

Although advances in technology have reduced the operative risk of elective abdominal aortic aneurysm (AAA) repair, the surgical repair of ruptured AAAs is associated with a much poorer prognosis and a higher cost. Accordingly, it has been suggested that patients with predictably high rates of morbidity and mortality from ruptured AAA may not benefit from surgical intervention.

METHODS AND RESULTS

A cost-effectiveness analysis was performed with the use of a Markov decision-analytic model to compute long-term survival in quality-adjusted life years and lifetime costs for a hypothetical cohort of patients with ruptured AAAs managed with either a strategy of open surgical repair or no intervention. Probability estimates for the various outcomes were based on a review of the literature. Average costs of (1) the immediate hospitalization ($28,356) and (2) complications resulting from the procedure were based on the average use of resources as reported in the literature and from a hospital's cost accounting system. Our measure of outcome was the incremental cost-effectiveness ratio. For our base-case analysis, the repair of ruptured AAAs was cost-effective with an incremental cost-effectiveness ratio of $10,754. (Society is usually willing to pay for interventions with cost-effectiveness ratios of less than $60,000; for example, the costeffectiveness ratios for coronary artery bypass grafting and dialysis are $9500 and $54,400, respectively.) In sensitivity analyses, the cost-effectiveness of repairing ruptured AAAs was influenced only by alterations in the operative mortality. If the operative mortality exceeded 88%, repair of ruptured AAAs was no longer cost-effective. As an independent variable, increasing age had no substantial impact on the cost-effectiveness, although it is reported to be associated with increased operative mortality. It was necessary that the patient's cost of the initial hospitalization for ruptured AAA exceed $195,000 before repairing ruptured AAAs was no longer cost-effective.

CONCLUSIONS

Our analysis suggests that despite the high cost and poor outcomes, the surgical repair of ruptured AAAs is still cost-effective when compared with no intervention. The cost of repairing ruptured AAAs falls within society's acceptable limits and therefore should not be a consideration in the management of patients with AAAs.

Intestinal ischemia and the gut-liver axis: an in vitro model

BACKGROUND

Sustained intestinal ischemic injury often leads to shock and multiorgan failure, mediated in part by a cytokine cascade. Animal models have also identified a central role of Kupffer cells in amplification of cytokines following intestinal ischemia. To better understand this gut-liver axis, we developed an in vitro model.

MATERIALS AND METHODS

Kupffer cells were isolated from rat livers by arabinogalactan gradient ultracentrifugation and adherence purification. Cells were grown in RPMI medium in 5% CO(2). Rat intestinal epithelial cells, IEC-6, were cultured under normoxic or anoxic (90% N(2), 10% CO(2)) conditions for 2, 12, and 24 h. Kupffer cells were then grown in the conditioned medium of the IEC-6 cultures. After 24 h, the medium was replaced with fresh medium. This final Kupffer cell supernatant was tested for tumor necrosis factor alpha and interleukin-6 production by ELISA. Trypan blue exclusion was performed to assess cell viability.

RESULTS

Intestinal and Kupffer cells remained viable during the experimental time. Production of both tumor necrosis factor alpha and interleukin-6 by Kupffer cells increased with increasing ischemia time of the intestinal cells.

CONCLUSIONS

Consistent with animal studies of intestinal ischemia, this study found an increase in cytokine production by Kupffer cells following hypoxia of intestinal cells. This in vitro model offers a new tool to study the expression of cytokines, proteins, and messengers involved in the cascade of events that follow intestinal ischemia.