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

Kinetics of d-lactate and ischemia-modified albumin after abdominal aortic surgery and their ability to predict intestinal ischemia

OBJECTIVES

Acute intestinal ischemia is a severe complication of abdominal aortic surgery that is difficult to diagnose early and therefore to treat adequately and timely. In this study the perioperative kinetics of d-lactate and ischemia-modified albumin (IMA) are described and the predictive value of these markers for the early diagnosis of acute intestinal ischemia is assessed.

DESIGN & METHODS

This non-randomised, single-centre cohort study enrolled 50 patients with abdominal aortic aneurysm (AAA) and 30 patients with aortoiliac occlusive disease (AOID). Serum d-lactate and IMA were assessed pre-, intra-, and postoperatively at eight defined time points.

RESULTS

The highest serum d-lactate was at 6 h after complete declamping of the vascular graft. The highest predictive power of d-lactate was at 3 h after complete declamping (AUC 0.857). IMA was found to be higher in the AAA group in ischemic patients 10 min after complete declamping than in the AOID group. The highest predictive values of IMA were at 1 h after aortic cross-clamping (AUC 0.758) and 3 and 6 h after complete declamping (0.745 and 0.721, respectively). Moreover, the multivariate model with both markers at 3 h after complete declamping improved the detection of intestinal ischemia (AUC 0.894).

CONCLUSIONS

Serum levels of IMA and d-lactate seem to be influential predictive markers for postoperative intestinal ischemia, especially after 3 h from complete declamping of vascular reconstruction.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

OBJECTIVES

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon.

METHODS

Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45 min, followed by 20 min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37 °C saline), and cold (4 °C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity.

RESULTS

Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45 mg/dL without renal perfusion, 0.33 mg/dL, and 0.14 mg/dL (p = .009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p = .002) and cold renal perfusion (p = .002). A smaller increase of ROS production (p = .034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p = .006) and cold perfusion (p = .018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p = .007) and cold renal perfusion (1.2AU; p = .002).

CONCLUSIONS

Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

[Colonic ischemia after open and endovascular aortic surgery : Epidemiology, Risk Factors, Diagnosis And Therapy]

Despite the successful establishment of endovascular techniques, colonic ischemia continues to be a serious complication of aortic surgery.The risk factors for colonic ischemia include aortic aneurysm rupture, prolonged aortic clamping, perioperative hypotension, the need for catecholamine therapy, occlusion of the hypogastric arteries and renal insufficiency.The clinical presentation of postoperative colonic ischemia is often unspecific. Classic symptoms include abdominal pain, diarrhea, peranal bleeding and rise of inflammatory parameters. A specific laboratory parameter for colonic ischemia does not exist. The diagnostic gold standard is endoscopy. Imaging methods such as sonography or computer tomography play only a supportive role. Transmural ischemia resulting in bowel wall necrosis is an indication for emergency surgery, predominantly colonic resection with creation of artificial anus.

Outcomes Following Inferior Mesenteric Artery Reimplantation During Elective Aortic Aneurysm Surgery

BACKGROUND

The role of inferior mesenteric artery (IMA) reimplantation during open aortic reconstruction is debated. We assessed outcomes after inferior mesenteric artery reimplantation (IMAR) for aortic aneurysmal disease to help shed light on this question.

METHODS

A single-center retrospective review of all IMARs performed during open aortic surgery over a 10-year period between 2000 and 2009 was carried out. The primary outcome was patency, while secondary outcomes included colonic ischemia and overall survival. Analysis was performed using Cox models and Kaplan-Meier estimates.

RESULTS

Of 840 patients who underwent elective abdominal aortic aneurysm (AAA) reconstructions during this period, 70 underwent IMAR. Indications for IMAR included intraoperative colonic ischemia (n = 24), poor back bleeding (n = 52), large IMA (n = 5), internal iliac disease (n = 5), and prior colon surgery (n = 1). Follow-up imaging studies were available in 35 of 70 patients (computed tomography in 30 [86%] and duplex in 5 [14%]). Patency was confirmed in 32 of 35 patients (91%) over a median follow-up of 98 months. Both losses in patency were at 4 months and did not require an operation. One patient underwent left colon resection on postoperative day 9 because of ischemia. (Patency could not be confirmed.) No statistically significant predictor of patency was noted. Incidence of colonic ischemia was 1.4% in patients undergoing IMAR. The overall mortality was 51% in patients undergoing IMAR over the median follow-up period. The overall 10-year survival was 30% in patients undergoing IMAR for aortic aneurysmal disease. The nature of aneurysm (juxtarenal or higher juxta renal abdominal aortic aneurysm [JRAAA]) was associated with mortality, with a hazard ratio of 1.8 (P = 0.08) approaching significance. Ten-year survival was worse if IMAR was performed for intraoperative colonic ischemia (26% vs 34%) or in JRAAA (19.0% vs 38%; P = 0.03). Age per year at the time of repair was the only statistically significant predictor of survival (P < 0.001).

CONCLUSION

IMAR for AAA remains necessary for select patients. Reimplantation is associated with excellent long-term patency and low risk of colonic ischemia.

An unusual cause of bowel ischemia in an intensive care unit patient with herpes simplex virus encephalitis

We present a case of an unexpected cause of bowel ischemia in an intensive care unit patient with herpes simplex virus encephalitis who required an operation. A 79-year-old lady was being worked up and treated for encephalitis with antibiotics and an antiviral. On Day 13, she developed abdominal pain, and an ultrasound showed cholelithiasis but no cholecystitis; thus conservative treatment was advocated. By Day 18, pain localized to the right iliac fossa, and she had an emergency laparotomy that showed bowel ischemia and perforation of the caecum with the cause being a terminal ileal adhesional band. An extended right hemicolectomy and ileostomy was performed. Patients with significant comorbidities who are intensive care unit-dependent may still have unexpected clinical challenges. We advocate an increased clinical vigilance in this cohort for unexpected life-threatening presentations such as bowel ischemia and more specifically the cause of the bowel ischemia.

Ischemic colitis following infrarenal abdominal aortic aneurysm treatment: Results from a tertiary medical center

OBJECTIVE

The aim of this study was to investigate the effects of ruptured aneurysm on morbidity and mortality in patients with ischemic colitis (IC) and resection following infrarenal abdominal aortic aneurysms (AAA) surgery.

METHODS

Between January 2012 and December 2016, patients who underwent resection for ischemic colitis in our clinic were retrospectively reviewed. Data on the ruptured condition of the aneurysm, the emergency or elective form of aneurysm surgery, treatment method for the aneurysm (EVAR-open) were obtained. The patients were compared and divided into two groups as those with ruptured aneurysm and those without.

RESULTS

A total of 275 infrarenal AAA cases were treated by the cardiovascular surgery clinic between January 2012 and December 2016. Fourteen patients (5%) developed ischemic colitis requiring resection. Four (1.8%) patients with EVAR and 10 (17.5%) patients with open surgery were operated because of IC. No statistically significant difference was observed between the two groups in terms of demographic data and surgical procedures. The intergroup comparison did not reveal any statistically significant difference among gastrointestinal (GIS) symptoms, the time period until surgery, the involved colon segment, and the surgical procedures performed. The mortality rate in ruptured AAA group was 83.3%, while it was 62.5% in the non-ruptured AAA group. In spite of the fact that the mortality rate was high in the ruptured group, it was not statistically significant (p=0.393).

CONCLUSION

IC is a complication of AAA surgery with a high mortality rate. Rupture in abdominal aortic aneurysm increasing mortality in IC patients. This complication with a high mortality rate following open AAA surgery should be noted by surgeons and we believe that the liberal utilization of laparotomy and early intervention in suspected cases will decrease mortality rates.

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.

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.

Limb remote ischemic preconditioning for intestinal and pulmonary protection during elective open infrarenal abdominal aortic aneurysm repair: a randomized controlled trial

BACKGROUND

Remote ischemic preconditioning (RIPC) may confer the cytoprotection in critical organs. The authors hypothesized that limb RIPC would reduce intestinal and pulmonary injury in patients undergoing open infrarenal abdominal aortic aneurysm repair.

METHODS

In this single-center, prospective, double-blinded, randomized, parallel-controlled trial, 62 patients undergoing elective open infrarenal abdominal aortic aneurysm repair were randomly assigned in a 1:1 ratio by computerized block randomization to receive limb RIPC or conventional abdominal aortic aneurysm repair (control). Three cycles of 5-min ischemia/5-min reperfusion induced by a blood pressure cuff placed on the left upper arm served as RIPC stimulus. The primary endpoint was arterial-alveolar oxygen tension ratio. The secondary endpoints mainly included the intestinal injury markers (serum intestinal fatty acid-binding protein, endotoxin levels, and diamine oxidase activity), the markers of oxidative stress and systemic inflammatory response, and the scores of the severity of intestinal and pulmonary injury.

RESULTS

In limb RIPC group, a/A ratio was significantly higher than that in control group at 8, 12, and 24 h after cross-clamp release (66 ± 4 vs. 45 ± 4, P = 0.003; 60 ± 6 vs. 37 ± 4, P = 0.002; and 60 ± 5 vs. 47 ± 6, P = 0.039, respectively). All biomarkers reflecting intestinal injury increased over time, and there was significant differences between limb RIPC and control group (P < 0.001). The severity of intestinal and pulmonary injury was decreased by limb RIPC (P = 0.014 and P = 0.001, respectively).

CONCLUSIONS

Limb RIPC attenuates intestinal and pulmonary injury in patients undergoing elective open infrarenal abdominal aortic aneurysm repair without any potential risk.

Regional variation in obstetrical intervention for hospital birth in the Republic of Ireland, 2005-2009

Background

Obstetrical interventions during childbirth vary widely across European and North American countries. Regional differences in intrapartum care may reflect an inpatient-based, clinician-oriented, interventional practice style.

Methods

Using nationally representative hospital discharge data, a retrospective cohort study was conducted to explore regional variation in obstetric intervention across four major regions (Dublin Mid Leinster; Dublin Northeast; South; West) within the Republic of Ireland. Specific focus was given to rates of induction of labour, caesarean delivery, epidural anaesthesia, blood transfusion, hysterectomy and episiotomy. Logistic regression analyses were performed to assess the association between geographical region and interventions while adjusting for patient case-mix.

Results

323,588 deliveries were examined. The incidence of interventions varied significantly across regions; the greatest disparities were observed for rates of induction of labour and caesarean delivery. Women in the South had nearly two-fold odds of having prostaglandins (adjusted OR: 1.75, 95% CI 1.68-1.82), whereas women in the West had 1.85 odds (95% CI 1.77-1.93) of artificial rupture of membrane. Women delivering in the Dublin Northeast, South and West regions had more than two-fold increased odds of elective caesarean delivery relative to women delivering in the Dublin Mid Leinster region. The Dublin Northeast region had the highest odds of emergency caesarean delivery (adjusted OR: 1.36; 95% CI: 1.31-1.40).

Conclusions

Substantial regional variation in intrapartum care was observed within this small, relatively homogeneous population. The association of intervention use with region illustrates the need to encourage uptake of scientific based practice guidelines to better inform clinical judgment.

Risk factors for postoperative complications after open infrarenal abdominal aortic aneurysm repair in Koreans

Purpose

Open infrarenal abdominal aortic aneurysm (AAA) repair is performed without event in most cases. However, some patients suffer major morbidities such as renal failure, myocardial infarction, paraplegia, acute respiratory distress syndrome, or hepatic dysfunction. Predicting what kinds of patient populations are more prone to develop such complications may keep the clinicians more attentive to the patients, possibly leading to better prognoses. In this retrospective study, we searched the incidence of and risk factors for postoperative complications and their predictive equations in 162 patients who underwent open infrarenal AAA repair.

Materials and Methods

Postoperative complications were observed within 30 days. Patient characteristics, types of aneurysm and surgery, and hemodynamic and metabolic variables during the periclamp period were analyzed in relation to postoperative complications using multiple logistic regression analysis.

Results

Postoperative complications involved the cardiac (20%), pulmonary (14%), renal (13%), gastrointestinal (6%), hepatic (3.1%), and neurologic (2.5%) systems, and bleeding occurred in 1.2% of cases. The mortality rate was 5.6%. The risk factors were age [> 67 yrs, odds ratio (OR) 2.6], clamp duration (> 110 min, OR 4.7), volume of blood transfusion (> 1,280 mL, OR 4.4), emergency operation (OR 1.4), and vasopressor infusion during clamp (OR 1.4). The prediction model was: P(x) = exp(α)/[1 + exp(α)] α;-2.2 + 0.9 × age + 1.5 × clamp duration + 1.5 × transfusion + 0.3 × emergency + 0.4 × vasopressor infusion [insert 1 if risk factors exist, otherwise, insert 0 to each variable].

Conclusion

A significant number of complications occurred after infrarenal AAA repair. Therefore, creating a protocol to identify and monitor high risk patients would improve postoperative care.

[Cytomegalovirus infection-related spontaneous intestinal perforation and aorto-enteric fistula after abdominal aortic aneurysmal repair]

Gastrointestinal complications (GI) after thoracoabdominal aortic repair can be classified as biliary disease, heptic dysfunction, pancreatitis, GI bleeding, peptic ulcer disease, bowel ischemia, paralytic ileus, and aortoenteric fistula. Theses complications are associated with high post operative morbidity and mortality. Most of the aortoenteric fistulae after thoracoabdominal aortic surgery are found at the duodenum, near the surgical site. These rare complications are caused by an indirect communication with abdominal aorta that originated from an aneursymal formation ruptured into the duodenum. Such aorto-duodenal fistula formation is considered as a result of inflammatory change from secondary infection near the surgical instruments. Herein, we report two cases of massive upper GI bleeding from aorto-duodenal fistulae and spontaneous lower GI perforation related to cytomegalovirus infection after abdominal aortic aneurysmal repair operations.