Intraoperative assessment of intestinal viability by laser Doppler flowmetry for surgery of ruptured abdominal aortic aneurysms

Acute Small-bowel Obstruction: An Appraisal of Common Etiology and Management at the Federal Medical Centre, Keffi, North-central Nigeria

BACKGROUND

Acute small intestinal obstruction is a common surgical emergency in the sub-Saharan region. Over the decades, complicated inguinal hernias have been identified as a leading cause. However, we observed from our clinical practice that complicated inguinal hernias were not the most common etiology.

AIMS AND OBJECTIVES

This study aimed to evaluate the common etiology of acute small bowel obstruction in the study center and compare our findings with that from other centers and existing literature.

MATERIALS AND METHODS

This was a retrospective, cross sectional study carried out over a period of five years (January 2017 to December 2021). This study looked at the patients presenting with acute, mechanical, small bowel obstruction that did not respond to conservative treatment in our hospital facility. Relevant information were extracted from patients' clinical details and entered into the proforma prepared for this study.

RESULTS

A total of 147 patients were recruited into this study out of which 85(57.8%) were males and 62 (42.2%) were females (M:F=1.44:1). Majority (80.3%) of the patients that presented with post-operative bowel adhesion had previous appendectomy. Simple bowel obstruction was seen in 93 (63.3%) patients while strangulated obstruction and gangrenous bowel were seen in 26 (17.7%) patients and 22 (15.0%) patients respectively. Majority (47.6%) of the patients had adhesiolysis done while others had bowel resection.

CONCLUSION

The common cause of acute small bowel obstruction as observed in this study is post-operative adhesions arising from previous appendectomy and laparotomies.

[Indications and surgical strategy for bowel resection in mesenteric ischemia : Resection margins considering current guidelines and literature as well as the influence of new technical possibilities]

Acute mesenteric ischemia (AMI) is still a time-critical and life-threatening clinical picture. If exploration of the abdominal cavity is necessary during treatment, an intraoperative assessment of which segments of the intestines have a sufficient potential for recovery must be made. These decisions are mostly based on purely clinical parameters, which are subject to high level of uncertainty. This review article provides an overview of how this decision-making process and the determination of resection margins can be improved using technical aids, such as laser Doppler flowmetry (LDF), indocyanine green (ICG) fluorescence angiography or hyperspectral imaging (HSI). Furthermore, this article compiles guideline recommendations on the role of laparoscopy and the value of a planned second-look laparotomy. In addition, an overview of strategies for preventing short bowel syndrome is given and other aspects, such as the timing and technical aspects of placement of a preternatural anus and an anastomosis are highlighted.

Strategy to Avoid Anastomotic Leakage in Laparoscopic Colorectal Resection Using the Indocyanine Green Fluorescence System

Purpose

Anastomotic leakage (AL) in colorectal resections is often caused by insufficient blood flow to the stump. Injecting indocyanine green can help detect blood flow intraoperatively. In this study, we evaluated our original strategy using an indocyanine green fluorescence system to avoid AL.

Methods

We retrospectively evaluated 79 patients who underwent laparoscopic colorectal resection for colon cancer using a double-stapling technique. Blood flow in oral stumps was evaluated by measuring indocyanine green fluorescence time (FT). We investigated AL cases in detail and analyzed correlations between FT and risk factors for AL.

Results

Of the 79 patients, 7 (8.9%) developed AL. We divided patients by FTs: >60 seconds, 50 to 60 seconds, and <50 seconds. The AL rates were FT >60 seconds, 60%; FT 50 to 60 seconds, 10.3%; and FT <50 seconds, 2.2%. The AL rate of high-risk cases (with more than 2 risk factors) were calculated and we made our original strategy to avoid AL as the following. Further resection or diverting stomas were needed by the FT >60 seconds group, and by members of the FT 50 to 60 seconds group with ≥3 risk factors. The FT <60 seconds group needed no additional management.

Conclusions

Patients with delayed FT (>60 seconds, or 50–60 seconds with ≥3 risk factors) may need revision of the anastomosis (diverting stoma or additional resection) to avoid AL. Our original strategy may contribute to reduce AL in colorectal operations.

Effectiveness of Intraoperative Indocyanine Green Fluorescence-Navigated Surgery for Superior Mesenteric Vein Thrombosis that Developed During Treatment for Intravascular Lymphoma: A Case Report

BACKGROUND Superior mesenteric vein thrombosis (SMVT) is a relatively rare form of acute abdominal disease; less than 0.1% of laparotomy surgeries are performed for SMVT. In the presence of severe intestinal ischemia or necrosis caused by SMVT, immediate surgical intervention is required. Macroscopic diagnosis of intestinal viability is sometimes difficult; its over-resection may carry the risk of short bowel syndrome. A near-infrared fluorescence imaging system with indocyanine green (ICG) has recently been developed for intraoperative, real-time evaluation of intestinal perfusion. This is the first report on the use of ICG fluorescence imaging during surgery for intestinal ischemia caused by venous thrombosis. CASE REPORT A 70-year-old man presented with a general feeling of weariness. On examination, he was diagnosed with intravascular large B cell lymphoma. R-CHOP therapy was initiated. On day 3 of initial R-CHOP therapy, the patient experienced sudden severe abdominal pain while in the hospital. Contrast-enhanced computed tomography revealed SMVT and loss of contrast effect in the small intestine. We diagnosed small bowel necrosis caused by SMVT, and exploratory laparotomy was performed, which revealed a continuous ischemia of 150 cm. Intraoperative ICG fluorescence imaging was utilized, and the color boundary was consistent with the ischemic area detected by visualization. The necrotic small intestine was excised and anastomosed. The patient was transferred to the hematology department on postoperative day 10 with no severe complications such as anastomotic leakage or re-thrombosis, and re-embolization was not observed 6 months later. CONCLUSIONS Venous thrombosis should be listed as a differential diagnosis when acute abdominal disease presents during chemotherapy for malignant lymphoma. ICG fluorescence imaging may be useful in the evaluation of intestinal blood flow for venous thrombosis.

Usefulness of blood flow evaluation by indocyanine green fluorescence system in laparoscopic anterior resection

BACKGROUND

One of the major cause of anastomotic leakage (AL) in anterior resection of the rectum is insufficient blood flow of the remnant colon. The indocyanine green fluorescence system (ICG-FS) can visualize the blood flow of organs intra-operatively. The aim of this study is to investigate the usefulness of ICG-FS for evaluating the blood flow of the remnant colon in laparoscopic anterior resection.

MATERIALS AND METHODS

Rectal cancer patients (n=24) who underwent laparoscopic anterior resection were included in this study. After resection of the rectum, 7.5mg of ICG was administered intravenously, and the blood flow of the oral stump was evaluated by the ICG-FS. The relationship between the fluorescence time (FT) of the oral stump and AL was investigated retrospectively.

RESULT

Two of twenty-four patients (8.3%) suffered AL. The FT of these two cases were over 60 seconds. In the case with the FT was over 80 seconds, we performed additional resection of the late fluorescence portion of the remnant colon and could avoid AL. In patients whose FT was under 60 seconds, no patients suffered AL.

CONCLUSION

ICG-FS may be useful for evaluating the blood flow of the remnant colon to avoid AL in laparoscopic anterior resection. J. Med. Invest. 66 : 65-69, February, 2019.

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.

A case of incarcerated femoral hernia with intestinal blood flow assessment by brightfield full-color near-infrared fluorescence camera: Report of a case

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We report the case of a patient with incarcerated obturator femoral hernia.

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The intestinal blood flow was evaluated by Indocyanine green (ICG) fluorescence.

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The bowel could be preserved after intraoperative evaluation of intestinal blood flow.

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PINPOINT, a brightfield color fluorescence camera was used for ICG fluorescence.

Introduction

Indocyanine green (ICG) fluorescence has been reported for examining intestinal blood flow (IBF), but not in the case of bowel released from entrapment in a femoral hernia. We report the case of a patient with incarcerated obturator femoral hernia in whom the bowel was preserved after evaluation of IBF with ICG fluorescence using a brightfield full-color near-infrared fluorescence camera.

Presentation of case

A woman in her 60s was diagnosed with incarcerated femoral hernia and underwent surgery. Laparotomy was performed to reduce bowel incarceration via an anterior approach. The small bowel showed deep-red discoloration on gross evaluation, but intravenous injection of ICG revealed uniform fluorescence of the mesentery and bowel wall. This indicated an absence of irreversible ischemic changes to the bowel, so resection was not performed and a modified Kugel herniorrhaphy was performed. The patient showed a good postoperative course.

Conclusion

In herniorrhaphy with mesh, minimization of bowel resection is important for preventing postoperative infection of the mesh. In this case, ICG fluorescence with a near-infrared fluorescence camera was central to reducing bowel resection.

ICG fluorescence may be useful for evaluating IBF in surgery for incarcerated femoral hernias.

Intestinal blood flow assessment by indocyanine green fluorescence imaging in a patient with the incarcerated umbilical hernia: Report of a case

After reduction of the incarceration during surgery for incarcerated hernia, intestinal blood flow (IBF) and the need for bowel resection must be evaluated. We report the case of a patient with incarcerated umbilical hernia in whom the bowel was preserved after evaluating IBF using indocyanine green (ICG) fluorescence. A woman in her 40s with a chief complaint of abdominal pain visited our hospital, was diagnosed with incarcerated umbilical hernia and underwent surgery. Laparotomy was performed to reduce bowel incarceration. After reducing the incarceration, IBF was observed using ICG fluorescence detected using a brightfield full-color fluorescence camera. The small bowel that had been incarcerated showed deep-red discoloration on gross evaluation, but intravenous injection of ICG revealed uniform fluorescence of the mesentery and bowel wall. This indicated an absence of irreversible ischemic changes of the bowel, so no resection was performed. The patient showed a good postoperative course, including resumption of eating on day 4 and discharge on day 11. In surgery for incarcerated hernia, ICG fluorescence may offer a useful method to evaluate IBF after reducing the incarceration. This case implied that PINPOINT could be used in open conventional surgery.

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We have reported the case of a patient with incarcerated umbilical hernia.

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The small bowel that had been incarcerated showed deep-red discoloration.

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The bowel could be preserved after intraoperative evaluation of intestinal blood flow.

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The intestinal blood flow was evaluated by ICG fluorescence.

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PINPOINT, a brightfield color fluorescence camera was used for ICG fluorescence.

Multidisciplinary stepwise management strategy for acute superior mesenteric venous thrombosis: an intestinal stroke center experience

BACKGROUD

Acute superior mesenteric venous thrombosis (ASMVT) is an uncommon but catastrophic abdominal vascular emergency with high rate of intestinal failure and mortality. The retrospective pilot study was performed to assess the effect of a multidisciplinary stepwise management strategy on survival and mesenteric recanalization in an integrated intestinal stroke center (ISC).

MATERIALS AND METHODS

A modern management strategy performed by multidisciplinary specialists in ISC was evaluated among 43 ASMVT patients that were classified into central vs peripheral type, operative vs nonoperative, early vs late treated group from March 2009 to April 2013. Patients received specific medical therapy, endovascular treatment, damage-control surgery, selective second-look laparotomy, critical care management, and clinical nutrition support in a stepwise way. The demographics, etiology, imaging characteristics, treatment procedures, complications, clinical outcome, and 1-year follow-up data were analyzed and compared. Confounding factors of mortality were identified by univariate and ROC-curve analysis. A single-center experience of over 5years for this modern strategy was also reported.

RESULTS

The protocol of multidisciplinary stepwise management strategy was followed in all ASMVT patients successfully. The 30-day mortality and recanalization rate were 11.63% and 90.70%. Initial damage-control surgery was carried out in 46.51% patients, with selective second-look laparotomy in 23.26% patients. Endovascular thrombolysis was performed in 83.72% patients initially or postoperatively. Bowel resection was necessary in 18 patients with the length of 100.00 (47.50, 222.50) cm. The incidence of short-bowel syndrome was 13.95%. The rate and length of bowel resection, short-bowel syndrome rate were significantly lower in nonoperative and early-treated groups (P<0.05). During the follow-up survey, 1-year survival was 83.72%, with no additional death or re-thrombosis.

CONCLUSION

A multidisciplinary stepwise management strategy involving modern surgical and endovascular treatments that focus on early mesenteric recanalization and bowel viability salvage in a specialized ISC could significantly improve the clinical outcome of ASMVT patients.

How to assess intestinal viability during surgery: A review of techniques

Objective and quantitative intraoperative methods of bowel viability assessment are essential in gastrointestinal surgery. Exact determination of the borderline of the viable bowel with the help of an objective test could result in a decrease of postoperative ischemic complications. An accurate, reproducible and cost effective method is desirable in every operating theater dealing with abdominal operations. Numerous techniques assessing various parameters of intestinal viability are described by the studies. However, there is no consensus about their clinical use. To evaluate the available methods, a systematic search of the English literature was performed. Virtues and drawbacks of the techniques and possibilities of clinical application are reviewed. Valuable parameters related to postoperative intestinal anastomotic or stoma complications are analyzed. Important issues in the measurement and interpretation of bowel viability are discussed. To date, only a few methods are applicable in surgical practice. Further studies are needed to determine the limiting values of intestinal tissue oxygenation and flow indicative of ischemic complications and to standardize the methods.

Intraoperative assessment of microperfusion with visible light spectroscopy for prediction of anastomotic leakage in colorectal anastomoses

PURPOSE

Anastomotic leakage is associated with increased morbidity and mortality. However, there is no accurate tool to predict its occurrence. We evaluated the predictive value of visible light spectroscopy (VLS), a novel method to measure tissue oxygenation [saturated O(2) (StO(2) )], for anastomotic leakage of the colon and the rectum.

METHOD

Oxygen saturation in the bowel was measured in 77 colorectal resections. The anastomosis was between 2 and 30 cm (mean 13 cm) from the anal verge. The oxygen saturation was measured in the colon and rectum before and after anastomosis construction. This was compared with a reference measurement in the caecum. Data on postoperative complications were prospectively collected.

RESULTS

Anastomotic leakage occurred in 14 (18%) patients. When compared with a leaking anastomosis, normal anastomoses showed rising O(2) values during the operation (mean StO(2) 72.1 ± 9.0-76.7 ± 8.0 vs 73.9 ± 7.9-73.1 ± 7.4) (P ≤ 0.05). There were also higher StO(2) values in the caecum compared with those which ultimately leaked (73.6 ± 5.7 normal anastomoses, 69.6 ± 5.6 anastomotic leaks) (P ≤ 0.05). Both StO(2) values were predictive of anastomotic leakage.

CONCLUSION

Tissue oxygenation O(2) appears to be a potentially useful means of predicting anastomotic leakage after colorectal anastomosis.

Acute mesenteric ischemia: diagnostic approach and surgical treatment

Mortality related to acute mesenteric arterial occlusion remains very high. Patient survival is dependent on prompt recognition and revascularization before ischemia progresses to intestinal gangrene. Biphasic computed tomography angiography has surpassed angiography as the diagnostic test of choice due to its ability to define the arterial anatomy and to evaluate secondary signs of mesenteric ischemia. Unlike chronic mesenteric ischemia, the treatment of acute arterial mesenteric ischemia, either embolic or thrombotic, remains largely surgical. This is due to the emergent need for revascularization combined with a careful evaluation of the intestines. Endovascular techniques remain useful, however, and can save precious time in the treatment of these challenging patients if integrated into a treatment pathway combined with definitive surgical treatment. A new hybrid endovascular-surgical treatment for the treatment of acute mesenteric thrombosis is described.

Mechanical obstruction of the small bowel and colon

Mechanical obstruction of the small bowel and colon is moderately common, accounting for several hundred thousand admissions per year in the United States. Patients generally present with abdominal pain, nausea and emesis, abdominal distention, and progressive obstipation. Clinical findings of high fever, localized severe abdominal tenderness, rebound tenderness, severe leukocytosis, or metabolic acidosis suggest possible complications of bowel necrosis, bowel perforation, or generalized peritonitis. Differentiation of total mechanical obstruction from partial mechanical obstruction and pseudo-obstruction is important because total mechanical obstruction is generally treated surgically,whereas the other two entities are usually treated medically. Mechanical obstruction is usually suggested by plain abdominal radiographs, and confirmed by small bowel follow through,abdominal CT, or CT enteroclysis.

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.

Ischemic colitis complicating major vascular surgery

Ischemic colitis is a well-described complication of major vascular surgery, especially following open abdominal aortic aneurysm repair and endovascular aneurysm repair, but also with aortoiliac surgery, aortic dissection, and thoracic aneurysm repair. Following its onset, mortality remains high, highlighting the need for rapidly identifying the onset of symptoms and, perhaps more importantly, those patients at risk, in an attempt to prevent its onset. In this article, the authors review the causes, presentation, and diagnostic strategies of colonic ischemia. They also cover the operative management and outcomes for bowel resection and vascular repair. Finally, they evaluate some of the newer options for diagnosing this condition.

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.

Evaluation of laser Doppler flowmetry for measurement of capillary blood flow in the stomach wall of dogs during gastric dilatation-volvulus

OBJECTIVES

To validate laser doppler flowmetry (LDF) for measurement of blood flow in the stomach wall of dogs with gastric dilatation-volvulus (GDV).

ANIMALS

Six purpose-bred dogs and 24 dogs with naturally occurring GDV.

STUDY DESIGN

Experimental and clinical.

METHODS

Capillary blood flow in the body of the stomach and pyloric antrum was measured with LDF (tissue perfusion unit (TPU) before and after induction of portal hypertension (PH) and after PH plus gastric ischemia (GI; PH + GI) and compared with flow measured by colored microsphere technique. Capillary flow was measured by LDF in the stomach wall of dogs with GDV.

RESULTS

PH and PH+GI induced a significant reduction in blood flow in the body of the stomach (P = .019). A significant positive correlation was present between percent changes in capillary blood flow measured by LDF and colored microspheres after induction of PH + GI in the body of the stomach (r = 0.94, P = .014) and in the pyloric antrum (r = 0.95, P = .049). Capillary blood flow measured in the body of the stomach of 6 dogs that required partial gastrectomy (5.00+/-3.30 TPU) was significantly lower than in dogs that did not (28.00+/-14.40 TPU, P = .013).

CONCLUSIONS

LDF can detect variations in blood flow in the stomach wall of dogs.

CLINICAL RELEVANCE

LDF may have application for evaluation of stomach wall viability during surgery in dogs with GDV.

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.

Intraperitoneal and intraluminal microdialysis in the detection of experimental regional intestinal ischaemia

BACKGROUND

The aim was to investigate the possibility of using intraluminal or intraperitoneal microdialysis to monitor regional intestinal ischaemia.

METHODS

Microdialysis catheters were inserted in the lumen, in and outside the intestinal wall, and in the peritoneum of each of ten pigs. Regional occlusive ischaemia was induced in 100 cm of jejunum. Levels of glucose, pyruvate, lactate and glycerol in the microdialysate were measured at 20-min intervals before and after induction of ischaemia. Systemic haemodynamics were monitored and laser Doppler flowmetry (LDF) recordings made in each of the intestinal segments.

RESULTS

Ischaemia caused a significant decrease in glucose level, and an increase in lactate and glycerol concentrations and lactate/pyruvate ratio, at all catheters, although glucose could not be detected by the intraluminal catheter. The metabolic changes occurred simultaneously and were statistically significant in almost all catheters after 100 min. LDF revealed a significant decrease in intestinal blood flow, but there was considerable individual variation.

CONCLUSION

Regional occlusive ischaemia in 100 cm of small intestine could be detected and monitored by means of a microdialysis catheter placed in the peritoneal cavity or the bowel lumen.

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.

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.

Intraoperative assessment of colonic perfusion using scanning laser Doppler flowmetry during colonic resection

BACKGROUND

Ischemia occurring on mobilization and mesenteric division is thought to be a major factor in the etiology of anastomotic dehiscence after colorectal resection. This study assessed the ability of the new technique of scanning laser Doppler flowmetry to measure changes in human colonic perfusion during mobilization at and adjacent to the anastomotic site.

STUDY DESIGN

Colonic perfusion was measured in 10 patients undergoing large-bowel resection by making laser Doppler scans of the proximal bowel before mobilization, after mobilization and mesenteric division, and after resection of the specimen. Mean perfusion was calculated within 1-cm2 regions of interest, each of which contained 1,750 individual measurements of perfusion. These regions represented the anastomosis site and adjacent areas 1 cm and 2 cm proximal and distal to this. The results were expressed as mean perfusion units (PUs).

RESULTS

After mobilization, there were significant decreases in perfusion in all the subjects between each time point and in all areas of the colon scanned. Median perfusion at the anastomosis site was 491 PUs before mobilization, and this fell to 212 PUs after mobilization, representing a decrease of 57%; the median within-person decrease was also 57% (p < 0.01). There was a gradient of reduced perfusion between the area 2 cm proximal to the mesenteric division (median within-person fall 25%; p < 0.05) and the area 2 cm distal to the mesenteric division (median within-person fall 84%; p < 0.01). After resection of the specimen, perfusion increased slightly at the anastomosis site to a median of 240 PUs (median within-person fall 41%; p < 0.01), but 2 cm proximal to this, median perfusion remained depressed at 330 PUs.

CONCLUSIONS

This new technique can be used intraoperatively and appears to overcome the limitations of single-point laser Doppler flowmetry. In this small preliminary study, it measured large decreases in colonic perfusion during mobilization, and it may have widespread clinical applications.

Anatomical importance of infrarenal aortic branches in conventional and endovascular surgery: a review

Minimally invasive or catheter-directed, endoluminal stent-graft treatment of abdominal aortic aneurysms (AAA) is a novel and important advance in the armamentarium of the vascular surgeon and interventional therapist. Provided adequate training is available, infrastructure is optimal, and patient selection correct, successful exclusion of AAA can safely and effectively be achieved with low morbidity and mortality by this lesser invasive technique. An important Achilles heel of endovascular repair (EVR) of AAA is back bleeding or endoleak formation due to incomplete sealing or bridging of aortic branches ostia by endoluminal stents. Significant, recurrent, and persistent retroleaks, a topic of clinical interest, are related to either incompletely sealed-off inferior mesenteric and/or lumbar arteries. The optimal method to diagnose and manage these endoleaks is currently in a state of evolution. In the process of stent-graft treatment of AAA, other important aortic branches are also bridged that may potentially present with the sequelae of peripheral ischemia. This review re-emphasizes the anatomical and clinical importance of abdominal aortic branches relevant to conventional aortic surgery and EVR of AAA.