Colonic ischaemia and intra-abdominal hypertension following open repair of 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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Use of Iliac Branched Devices in the Acute Endovascular Repair of Ruptured Aortoiliac Aneurysms

BACKGROUND

The objective of this study was to evaluate the feasibility and midterm outcomes of iliac branch devices (IBDs) to preserve the internal iliac artery perfusion in emergent endovascular repair of ruptured aorto-iliac aneurysms.

METHODS

Between December 2012 and July 2017, a total of 8 IBDs were implanted in 6 patients (the median age 65 years; all men) in a single tertiary referral center. The indication for IBD implantation was a ruptured abdominal aortic aneurysm with a concomitant common iliac artery aneurysm (n = 4) or isolated CIA aneurysms (n = 2). The main outcome measures were technical and clinical success. The secondary outcomes were primary and primary assisted patency, the occurrence of type I/III endoleaks, and reinterventions.

RESULTS

All patients were hemodynamically stable during the procedures, which were performed under local anesthesia. Technical success was achieved in all cases (the median total procedure time of 188 min and the median IBD procedure time of 28 min). The median follow-up was 34 months (interquartile range 19-78). There were no deaths during the follow-up and no major complications unrelated to the IBD. Two (25%) secondary interventions were performed for IBD occlusion in patients with bilateral IBDs. The other reintervention was a type II endoleak embolization in 1 of these 2 patients. The freedom from reintervention estimate was 75% through 2 years. The overall primary assisted patency was 100% through 3 years.

CONCLUSIONS

The use of IBDs in the acute setting is feasible to exclude ruptured aortoiliac aneurysms while maintaining pelvic circulation. The secondary intervention rate is considerable; however, the midterm assisted primary patency rates are promising. Further studies are needed to guide patient selection and to evaluate longer term outcomes.

[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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Incidence, Predictors, and Outcomes of Colonic Ischaemia in Abdominal Aortic Aneurysm Repair

OBJECTIVE/BACKGROUND

Colonic ischaemia (CI) is a severe complication following abdominal aortic aneurysm (AAA) repair, leading to high morbidity and mortality. The aim of the study was to determine the incidence, predictors, and outcomes of CI following AAA repair.

METHODS

National claims from Germany's third largest insurance provider, DAK-Gesundheit, were used to investigate CI after intact (iAAA) and ruptured (rAAA) AAA repairs. Patients undergoing endovascular (EVAR) or open surgical (OSR) repairs between January 2008 and December 2017 were included in the study.

RESULTS

There were 9145 patients (8248 iAAA and 897 rAAA) undergoing EVAR or OSR procedures and the median follow up was 2.28 years. Most patients were male (79.2% iAAA, 79.3% rAAA); the median age was 73.0 years (iAAA group) and 76.0 years (rAAA group). Overall, CI occurred 97 (1.2%) times after iAAA and 95 (10.6%) after rAAA. In univariable analyses CI occurred less often after EVAR than after OSR (0.6% vs. 3.7%; p < .001). Acute post-operative renal and respiratory insufficiencies were also related to the occurrence of CI (p < .001). CI was associated with greater in hospital mortality (42.2% vs. 2.7% for iAAA, 64.2% vs. 36.3% for rAAA; p < .001) and lower long-term survival for iAAA (Kaplan-Meier analysis). In multivariable analyses, rAAA (odds ratio [OR] 5.59), and higher van Walraven comorbidity score (OR 1.09) were independently associated with greater risk of CI occurrence. EVAR use (OR 0.30) was protective. EVAR use remained protective in stratified analyses within iAAA (OR 0.32) and rAAA (OR 0.26).

CONCLUSION

Post-operative CI after AAA repair is not common but is associated with worse in hospital outcomes and lower long-term survival. EVAR was protective after both rAAA and iAAA repairs. When discussing the treatment of AAA with patients the protective effect of EVAR should be considered. Future studies should validate predictive scores and advance preventive strategies.

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.

Advents in the Diagnosis and Management of Ischemic Colitis

BACKGROUND

Ischemic colitis (IC) is a common type of ischemic insult, resulting from decreased arterial blood flow to the colon. This disease can be caused from either atherosclerotic occlusive vascular disease or non-occlusive disease. The aim of this study is to present the diagnostic methodology and management of this severe disease based on current literature.

METHODS

A literature search has been done including articles referring to modern diagnosis and management of IC.

RESULTS

IC is usually a transient disease, but it can also cause gangrene of the colon, requiring emergency surgical exploration. Diagnosis is troublesome and is based on imaging examinations, mainly computerized tomography, which in association with colonoscopy can delineate the distribution pattern and severity of disease.

CONCLUSION

The majority of patients with mild disease have usually complete clinical recovery within a short period. The severe forms of the disease carry high morbidity and mortality rates and prompt surgical intervention is the only way to improve the associated severe prognosis.

Open abdomen critical care management principles: resuscitation, fluid balance, nutrition, and ventilator management

The term "open abdomen" refers to a surgically created defect in the abdominal wall that exposes abdominal viscera. Leaving an abdominal cavity temporarily open has been well described for several indications, including damage control surgery and abdominal compartment syndrome. Although beneficial in certain patients, the act of keeping an abdominal cavity open has physiologic repercussions that must be recognized and managed during postoperative care. This review article describes these issues and provides guidelines for the critical care physician managing a patient with an open abdomen.

Abdominal Compartment Syndrome and Intra-abdominal Ischemia in Patients with Severe Acute Pancreatitis

Introduction

Severe acute pancreatitis may be complicated by intra-abdominal hypertension (IAH), abdominal compartment syndrome (ACS), and intestinal ischemia. The aim of this retrospective study is to describe the incidence, treatment, and outcome of patients with severe acute pancreatitis and ACS, in particular the occurrence of intestinal ischemia.

Methods

The medical records of all patients admitted with severe acute pancreatitis admitted to the ICU of a tertiary referral center were reviewed. The criteria proposed by the World Society of the Abdominal Compartment Syndrome (WSACS) were used to determine whether patients had IAH or ACS.

Results

Fifty-nine patients with severe acute pancreatitis were identified. Intra-abdominal pressure (IAP) measurements were performed in 29 patients (49.2 %). IAH was present in all patients (29/29). ACS developed in 13/29 (44.8 %) patients. Ten patients with ACS underwent decompressive laparotomy. A large proportion of patients with ACS had intra-abdominal ischemia upon laparotomy: 8/13 (61.5 %). Mortality was high in both the ACS group and the IAH group.

Conclusion

This study confirms that ACS is common in severe acute pancreatitis. Intra-abdominal ischemia occurs in a large proportion of patients with ACS. Swift surgical intervention may be indicated when conservative measures fail in patients with ACS. National and international guidelines need to be updated so that routine IAP measurements become standard of care for patients with severe acute pancreatitis in the ICU.

Perfusion of the gastric conduit during esophagectomy

In esophageal cancer surgery, perfusion of the gastric conduit is a critical issue. Measurement of gastric intramucosal pH (pHi) is a method to identify anaerobic metabolism as a sign of impaired perfusion. In this study we aimed to monitor changes in the perfusion of the gastric conduit at key steps during and after esophagectomy. pHi was measured per- and postoperatively using intermittent gastric tonometry in 32 patients undergoing open, 65%, or video-assisted thoracoscopic esophagectomy for esophageal cancer. Measurements focused on the surgical steps when the vascular supply to the gastric conduit was altered. A tonometry catheter was successfully placed in all patients and a decrease in pHi (mean ± SD) was observed from baseline to after the division of the short gastric vessels (7.33 ± 0.07 to 7.29 ±  0.07, P  = 0.005). A further reduction after the ligation of the left gastric artery (7.26 ± 0.08, P  < 0.001) and after final linear stapling the gastric conduit (7.15 ± 0.13, P  < 0.001) was observed. Two hours after surgery, pHi increased (7.24 ± 0.09, P  = 0.002). In contrast to open surgery, a trend towards less reduction in pHi was seen in thoracoscopic surgery. Patients with anastomotic leaks had lower pHi on the first postoperative day (7.12 ± 0.05 vs. 7.27 ± 0.08, P  = 0.040). It can be concluded that each surgical step altering the vascular supply to the gastric conduit resulted in detectable changes, however transient, in pHi. Patients with low pHi on the first postoperative day were more prone to have clinically relevant anastomotic leaks.

Effects of norepinephrine on tissue perfusion in a sheep model of intra-abdominal hypertension

BACKGROUND

The aim of the study was to describe the effects of intra-abdominal hypertension (IAH) on regional and microcirculatory intestinal blood flow, renal blood flow, and urine output, as well as their response to increases in blood pressure induced by norepinephrine.

METHODS

This was a pilot, controlled study, performed in an animal research laboratory. Twenty-four anesthetized and mechanically ventilated sheep were studied. We measured systemic hemodynamics, superior mesenteric and renal blood flow, villi microcirculation, intramucosal-arterial PCO2, urine output, and intra-abdominal pressure. IAH (20 mm Hg) was generated by intraperitoneal instillation of warmed saline. After 1 h of IAH, sheep were randomized to IAH control (n = 8) or IAH norepinephrine (n = 8) groups, for 1 h. In this last group, mean arterial pressure was increased about 20 mm Hg with norepinephrine. A sham group (n = 8) was also studied. Fluids were administered to prevent decreases in cardiac output. Differences between groups were analyzed with two-way repeated measures of analysis of variance (ANOVA).

RESULTS

After 2 h of IAH, abdominal perfusion pressure decreased in IAH control group compared to IAH norepinephrine and sham groups (49 ± 11, 73 ± 11, and 86 ± 15 mm Hg, P < 0.0001). There were no differences in superior mesenteric artery blood flow, intramucosal-arterial PCO2, and villi microcirculation among groups. Renal blood flow (49 ± 30, 32 ± 24, and 102 ± 45 mL.min(-1).kg(-1), P < 0.0001) and urinary output (0.3 ± 0.1, 0.2 ± 0.2, and 1.0 ± 0.6 mL.h(-1).kg(-1), P < 0.0001) were decreased in IAH control and IAH norepinephrine groups, compared to the sham group.

CONCLUSIONS

In this experimental model of IAH, the gut and the kidney had contrasting responses: While intestinal blood flow and villi microcirculation remained unchanged, renal perfusion and urine output were severely compromised.

[Open treatment of abdominal compartment syndrome after contained aortic aneurysm rupture]

For the first time in Hungary, a patient with abdominal compartment syndrome after contained aortic aneurysm rupture was treated successfully implementing open abdomen treatment with vacuum-assisted wound closure (V.A.C.) and delayed abdominal wall closure with mesh.

CASE REPORT

Contained aortic aneurysm rupture was diagnosed by CT angiography in a 59-year-old patient. After the acute reconstruction of the ruptured aorta (by an open procedure with aorto-aortic Dacron interposition) during the closure of the abdominal cavity the patient could not be effectively ventilated due to high intra-abdominal pressure caused by the severe oedema of the abdominal wall and the hematoma in the retroperitoneal space. In this situation, we decided upon open abdominal treatment using V.A.C. After regular changes of V.A.C. the abdomen was closed with DualMesh and three weeks later the patient was discharged home in good condition.

CONCLUSION

In our case, abdominal closure was not implemented after the reconstruction of the ruptured aortic aneurysm due to the extensive oedema. The complications of abdominal compartment syndrome were prevented with the open treatment. Based on our experience and on the results of the international literature we highly recommend open abdominal treatment with V.A.C. in case of abdominal compartment syndrome.

Prospective study examining clinical outcomes associated with a negative pressure wound therapy system and Barker's vacuum packing technique

BACKGROUND

The open abdomen has become a common procedure in the management of complex abdominal problems and has improved patient survival. The method of temporary abdominal closure (TAC) may play a role in patient outcome.

METHODS

A prospective, observational, open-label study was performed to evaluate two TAC techniques in surgical and trauma patients requiring open abdomen management: Barker's vacuum-packing technique (BVPT) and the ABThera(TM) open abdomen negative pressure therapy system (NPWT). Study endpoints were days to and rate of 30-day primary fascial closure (PFC) and 30-day all-cause mortality.

RESULTS

Altogether, 280 patients were enrolled from 20 study sites. Among them, 168 patients underwent at least 48 hours of consistent TAC therapy (111 NPWT, 57 BVPT). The two study groups were well matched demographically. Median days to PFC were 9 days for NPWT versus 12 days for BVPT (p = 0.12). The 30-day PFC rate was 69 % for NPWT and 51 % for BVPT (p = 0.03). The 30-day all-cause mortality was 14 % for NPWT and 30 % for BVPT (p = 0.01). Multivariate logistic regression analysis identified that patients treated with NPWT were significantly more likely to survive than the BVPT patients [odds ratio 3.17 (95 % confidence interval 1.22-8.26); p = 0.02] after controlling for age, severity of illness, and cumulative fluid administration.

CONCLUSIONS

Active NPWT is associated with significantly higher 30-day PFC rates and lower 30-day all-cause mortality among patients who require an open abdomen for at least 48 h during treatment for critical illness.

Abdominal hypertension and decompression: the effect on peritoneal metabolism in an experimental porcine study

OBJECTIVE

The aim of this study was to investigate the abdominal metabolic response and circulatory changes after decompression of intra-abdominal hypertension in a porcine model.

METHODS

This was an experimental study with controls. Three-month-old domestic pigs of both sexes were anesthetized and ventilated. Nine animals had a pneumoperitoneum-induced IAH of 30 mmHg for 6 hours. Twelve animals had the same IAH for 4 hours followed by decompression, and were monitored for another 2 hours. Hemodynamics, including laser Doppler-measured mucosal blood flow, urine output, and arterial blood samples were analyzed every hour along with glucose, glycerol, lactate and pyruvate concentrations, and lactate-pyruvate (l/p) ratio, measured by microdialysis.

RESULTS

Laser Doppler-measured mucosal blood flow and urine output decreased with the induction of IAH and showed a statistically significant resolution after decompression. Both groups developed distinct metabolic changes intraperitoneally on induction of IAH, including an increased l/p ratio, as signs of organ hypoperfusion. In the decompression group the intraperitoneal l/p ratio normalized during the second decompression hour, indicating partially restored perfusion.

CONCLUSION

Decompression after 4 hours of IAH results in an improved intestinal blood flow and a normalized intraperitoneal l/p ratio.

Management of abdominal compartment syndrome and the open abdomen

OBJECTIVES

The management of the abdominal compartment syndrome (ACS) and the open abdomen (OA) are important to improve survival after major vascular surgery, in particular ruptured abdominal aortic aneurysm (RAAA). The aim is to summarize contemporary knowledge in this field.

METHODS

The consensus definitions of the World Society of the Abdominal Compartment Syndrome (WSACS) that were published in 2006 and the clinical practice guidelines published in 2007 were updated in 2013. Structured clinical questions were formulated (modified Delphi method), and the evidence base to answer those questions was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines.

RESULTS

Most of the previous definitions were kept untouched, or were slightly modified. Four new definitions were added, including a definition of OA and of lateralization of the abdominal wall, an important clinical problem to approach during prolonged OA treatment. A classification system of the OA was added. Seven recommendations were formulated, in summary: Trans-bladder intra-abdominal pressure (IAP) should be monitored in patients at risk. Protocolized monitoring and management are recommended, and decompression laparotomy if ACS. When OA, protocolized efforts to obtain an early abdominal fascial closure, and strategies utilizing negative pressure wound therapy should be used, versus not. In most cases the evidence was graded as weak or very weak. In six of the structured clinical questions, no recommendation could be made.

CONCLUSION

This review summarizes changes in definitions and management guidelines of relevance to vascular surgery, and data on the incidence of ACS after open and endovascular aortic surgery.

Modern treatment of acute mesenteric ischaemia

BACKGROUND

Diagnosis of acute mesenteric ischaemia in the early stages is now possible with modern computed tomography (CT), using intravenous contrast enhancement and imaging in the arterial and/or portal venous phase. The availability of CT around the clock means that more patients with acute mesenteric ischaemia may be treated with urgent intestinal revascularization.

METHODS

This was a review of modern treatment strategies for acute mesenteric ischaemia.

RESULTS

Endovascular therapy has become an important alternative, especially in patients with acute thrombotic superior mesenteric artery (SMA) occlusion, where the occlusive lesion can be recanalized either antegradely from the femoral or brachial artery, or retrogradely from an exposed SMA after laparotomy, and stented. Aspiration embolectomy, thrombolysis and open surgical embolectomy, followed by on-table angiography, are the treatment options for embolic SMA occlusion. Endovascular therapy may be an option in the few patients with mesenteric venous thrombosis who do not respond to anticoagulation therapy. Laparotomy is needed to evaluate the extent and severity of visceral organ ischaemia, which is treated according to the principles of damage control surgery.

CONCLUSION

Modern treatment of acute mesenteric ischaemia involves a specialized approach that considers surgical and, increasingly, endovascular options for best outcomes.

Risk factors and outcomes associated with acute kidney injury following ruptured abdominal aortic aneurysm

Background

Current data describing the epidemiology of acute kidney injury (AKI) following repair of ruptured abdominal aortic aneurysm (rAAA) are limited and long-term outcomes are largely unknown. Our objectives were to describe the incidence rate, risk factors, clinical course and long-term outcomes of AKI following rAAA repair.

Methods

Retrospective population-based cohort study of all referrals undergoing emergency repair of rAAA in Northern Alberta from January 1, 2002 to December 31 2009. Demographic, clinical, physiologic and laboratory data were extracted. AKI was defined and classified according to the AKIN criteria.

Results

In total, 140 patients survived to receive emergent rAAA repair. Post-operative AKI occurred in 75.7% of patients (n = 106), 78.3% (n = 83) of which occurred during the initial 24 hours of ICU admission. AKIN stage 1, 2, and 3 occurred in 47 (33.6%), 36 (25.7%) and 23 (16.4%), respectively, with 19 patients receiving renal replacement therapy (RRT). Several clinical and biochemical patient factors were associated with incident AKI, including baseline estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² (odds ratio [OR] 2.94; 95% CI, 1.15-7.51, p = 0.03), need for mechanical ventilation (OR 22.7; 95% CI, 7.0-72.1, p < 0.0001) and vasoactive therapy (OR 9.9; 95% CI, 3.0-32.2, p < 0.0001) and higher mean APACHE II scores (25.7 [8.2] vs. 16.3 [4.9], p < 0.0001). AKI was associated with a higher ICU (28.3% vs. 0%; p = 0.0008) and in-hospital case-fatality rate (35.9% vs. 0%, p = 0.0001). Of 102 survivors to discharge, 65.7% (n = 67) recovered to baseline kidney function. In multivariable analysis, greater severity of AKI (OR 5.01; 95% CI, 2.34-10.7, p < 0.001) and lower baseline eGFR (OR 0.96; 95% CI, 0.93-0.99, p = 0.03) were associated with non-recovery. AKI remained independently associated with 1-year mortality after adjusting for age, sex, comorbidity, and illness severity (OR 5.21; 95% CI, 1.04-26.2, p = 0.045; AUC 0.83; H-L GoF, p = 0.26). Among survivors at 1-year, only 63.4% (n = 55) had complete kidney recovery.

Conclusions

Following rAAA repair, AKI is a common complication independently associated with long-term post-operative mortality. A significant proportion of AKI sufferers in this setting fail to recover to baseline kidney function.

Management of the tense abdomen or difficult abdominal closure after operation for ruptured abdominal aortic aneurysms

Increased intra-abdominal pressure (IAP) and abdominal compartment syndrome (ACS) are important clinical problems after repair of ruptured abdominal aortic aneurysms and are reviewed here. IAP >20 mm Hg occurs in approximately 50% of patients treated with open abdominal aortic aneurysm repair after rupture, and approximately 20% develop organ failure or dysfunction, fulfilling the criteria for ACS. Patients selected for endovascular aneurysm repair are often more hemodynamically stable, perhaps related to not handling the viscera or more favorable anatomy, resulting in less bleeding and, consequently, decreased risk of developing ACS. Centers that treat most patients with endovascular aneurysm repair tend to have the same proportion of ACS as after open repair. There are no randomized data on these aspects. Early nonsurgical therapy can prevent development of ACS. Medical therapy includes neuromuscular blockade and the combination of positive end-expiratory pressure, albumin, and furosemide. This proactive strategy can reduce the number of decompressive laparotomies, an important detail because treatment of ACS with open abdomen is a morbid procedure. When treatment with an open abdomen is necessary, it is important to choose a temporary abdominal closure that maintains sterile conditions during often prolonged treatment. In addition, it should prevent lateralization of the bowel wall and adhesions between the intestines and the bowel wall. Enteroatmospheric fistulae must be prevented. Many alternative methods have been suggested, but we prefer the combination of vacuum-assisted wound closure with mesh-mediated traction, which will be described.

Utility of measurements of abdominal perfusion pressure as a measure of isovolemic status and intestinal perfusion in patients with ruptured aortic aneurysm

Ruptured abdominal aorta aneurysm of ten results in intraabdominal hypertension (IAH). When IAH exceeds 20 mm Hg, intestinal ischemia can result that is a common cause of severe postoperative complications, including death.

THE AIM OF THE STUDY

was to evaluate utility of measurement of abdominal perfusion pressure (APP) to estimate intestinal perfusion and isovolemic status in patients undergoing surgical treatment for ruptured abdominal aorta aneurysm.

MATERIAL AND METHODS

A group of 40 patients of either sex, aged 47-93 years (average age 70 ± 10) was treated at an Intensive Care Unit after surgical reconstruction of abdominal aorta due to ruptured aortic aneurysm. The study was prospective. The following were measured: parameters of intraabdominal pressure (intraabdominal pressure - IAP, abdominal perfusion pressure - APP); parameters of intestinal perfusion - tonometric (intramucosal gastric carbon dioxide partial pressure PgCO(2), intramucosal-arterial difference in carbon dioxide partial pressure - Pg-aCO(2)); hemodynamic parameters (mean arterial pressure - MAP, central venous pressure - CVP).

RESULTS

A statistically significant correlation was demonstrated between parameters of visceral perfusion and abdominal perfusion pressure. Pearson correlation coefficient for APP/PgCO(2) and APP/Pg-aCO(2) was negative and was -0.4664 and -0.3498, respectively.

CONCLUSIONS

Abdominal perfusion pressure is an useful parameter in the evaluation of intestinal perfusion in IAH patients after surgical treatment of ruptured aortic aneurysm. MAP reflects current physiological body reserves at a critical stage of the disease, informing about possibility to provide visceral perfusion and indirectly, about adequacy of fluid replacement therapy. In intraabdominal hypertension, CVP is falsely elevated, making it of low utility in the evaluation of volemic status and intestinal perfusion.

The effect of diabetes on mortality in critically ill patients: a systematic review and meta-analysis

Introduction

Critically ill patients with diabetes are at increased risk for the development of complications, but the impact of diabetes on mortality is unclear. We conducted a systematic review and meta-analysis to determine the effect of diabetes on mortality in critically ill patients, making a distinction between different ICU types.

Methods

We performed an electronic search of MEDLINE and Embase for studies published from May 2005 to May 2010 that reported the mortality of adult ICU patients. Two reviewers independently screened the resultant 3,220 publications for information regarding ICU, in-hospital or 30-day mortality of patients with or without diabetes. The number of deaths among patients with or without diabetes and/or mortality risk associated with diabetes was extracted. When only crude survival data were provided, odds ratios (ORs) and standard errors were calculated. Data were synthesized using inverse variance with ORs as the effect measure. A random effects model was used because of anticipated heterogeneity.

Results

We included 141 studies comprising 12,489,574 patients, including 2,705,624 deaths (21.7%). Of these patients, at least 2,327,178 (18.6%) had diabetes. Overall, no association between the presence of diabetes and mortality risk was found. Analysis by ICU type revealed a significant disadvantage for patients with diabetes for all mortality definitions when admitted to the surgical ICU (ICU mortality: OR [95% confidence interval] 1.48 [1.04 to 2.11]; in-hospital mortality: 1.59 [1.28 to 1.97]; 30-day mortality: 1.62 [1.13 to 2.34]). In medical and mixed ICUs, no effect of diabetes on all outcomes was found. Sensitivity analysis showed that the disadvantage in the diabetic surgical population was attributable to cardiac surgery patients (1.77 [1.45 to 2.16], P < 0.00001) and not to general surgery patients (1.21 [0.96 to 1.53], P = 0.11).

Conclusions

Our meta-analysis shows that diabetes is not associated with increased mortality risk in any ICU population except cardiac surgery patients.

Ruptured AAA: open surgical management

Ruptured abdominal aorta aneurysm (rAAA) is the 13th leading cause of death in the United States. Despite many advances in the field of vascular surgery, the improvement in mortality rates of rAAA have been very modest. Although endovascular repair has surpassed open repair for elective AAA repair in the United States, open rAAA repair remains the most common therapy for this devastating vascular emergency. In this article, we discuss open surgical management for rAAA. We also describe a fast-track algorithm we have developed at the University of Massachusetts where open and endovascular repairs play equally important roles in management of rAAA.

Nonocclusive mesenteric hypoperfusion syndromes: recognition and treatment

The main focus when discussing acute or chronic mesenteric ischemia is on occlusive disease, arterial or venous. This article reviews present knowledge on mesenteric nonocclusive hypoperfusion syndromes. The following three clinical entities are reviewed: (1) Intraabdominal hypertension (IAH), or abdominal compartment syndrome (ACS), is important after ruptured abdominal aortic aneurysm repair. IAH >20 mm Hg occurs in approximately 50% of patients after open repair and in 20% after endovascular repair of ruptured abdominal aortic aneurysm, but these patients are different and no randomized data exists yet. A consensus issued by the World Society of Abdominal Compartment Syndrome provides guidance. Early conservative treatment of IAH and, alternatively, abdominal closure devices for leaving the abdomen partially open temporarily are discussed and a treatment algorithm is suggested. (2) Colonic ischemia after abdominal aortic surgery, its risk factors, clinical presentation, and treatment are discussed. A significant number of such patients develop IAH and reducing the abdominal perfusion pressure affects the left colon, the sentinel organ in these patients. (3) Nonocclusive mesenteric ischemia (NOMI); most often such patients suffer from severe cardiac failure requiring massive inotropic support. The condition is difficult to define. Early diagnosis with multidetector row computed tomography is a worthwhile alternative when angiography presents difficulties. A stenosis of the superior mesenteric artery is frequently enough that it should be ruled out because endovascular treatment can be lifesaving. New knowledge on these three different mesenteric hypoperfusion syndromes is reviewed. Success in treating these difficult patients is benefited from a multidisciplinary approach.

Effect of early plasma transfusion on mortality in patients with ruptured abdominal aortic aneurysm

BACKGROUND

The ratio of red blood cell (PRBC) transfusion to plasma (FFP) transfusion (PRBC:FFP ratio) has been shown to impact survival in trauma patients with massive hemorrhage. The purpose of this study was to determine the effect of the PRBC:FFP ratio on mortality for patients with massive hemorrhage after ruptured abdominal aortic aneurysm (RAAA).

METHODS

A retrospective review was performed of patients undergoing emergent open RAAA repair from January 1987 to December 2007. Patients with massive hemorrhage (≥10 units of blood products transfused prior to conclusion of the operation) were included. The effects of patient demographics, admission vital signs, laboratory values, peri-operative variables, amount of blood products transfused, and the PRBC:FFP ratio on 30-day mortality were analyzed by multivariate analysis.

RESULTS

One hundred and twenty-eight of the 168 (76%) patients undergoing repair for RAAA received at least 10 units of blood products within the peri-operative period. Mean age was 73.1 ± 9.1 years, and 109 (85%) were men. Thirty-day mortality was 22.6% (29/128), including 11 intra-operative deaths. By multivariate analysis, 30-day mortality was markedly lower (15% vs 39%; P < .03) for patients transfused at a PRBC:FFP ratio ≤2:1 (HIGH FFP group) compared with those transfused at a ratio of >2:1 (LOW FFP), and the likelihood of death was more than 4-fold greater in the LOW FFP group (odds ratio 4.23; 95% confidence interval, 1.2-14.49). Patients in the HIGH FFP group had a significantly lower incidence of colon ischemia than those in the LOW FFP group (22.4% vs 41.1%; P = .004).

CONCLUSION

For RAAA patients requiring massive transfusion, more equivalent transfusion of PRBC to FFP (HIGH FFP) was independently associated with lower 30-day mortality. The lower incidence of colonic ischemia in the HIGH FFP group may suggest an additional benefit of early plasma transfusion that could translate into further mortality reduction. Analysis from this study suggests the potential feasibility for a more standardized protocol of initial resuscitation for these patients, and prospective studies are warranted to determine the optimum PRBC:FFP ratio in RAAA patients.

Early results after treatment of open abdomen after aortic surgery with mesh traction and vacuum-assisted wound closure

OBJECTIVES

This study aimed to describe the use of vacuum-assisted wound closure (VAWC) and mesh traction to repair an open abdomen after aortic surgery.

DESIGN

Prospective clinical study.

MATERIAL AND METHODS

From October 2006 to April 2009, nine consecutive patients were treated; seven of the patients received laparostomy following abdominal compartment syndrome (ACS), while two wounds were left open initially. The indication for laparostomy was intra-abdominal pressure (IAP) > 20 mmHg or abdominal perfusion pressure (APP) < 60 mmHg and development of organ failure. V.A.C. therapy (KCI, San Antonio, TX, USA) was initiated with the laparostomy, and supplemented with a fascial mesh after 2 days. The wound was then closed stepwise with mesh traction and VAWC.

RESULTS

All wounds could be closed following a median interval of 10.5 (range: 6-19) days after laparostomy. A median of four (range: 2-7) dressing changes were performed. One patient died on the seventh postoperative day. Two other patients died 38 and 50 days after final closure, respectively. Left colonic necrosis was seen in two patients while incisional hernia was observed in two patients. Mean follow-up duration was 17 (range: 2-36) months.

CONCLUSION

VAWC with mesh traction was successful in terms of early delayed primary closure and is a useful tool in the treatment of open abdomen after aortic surgery.

Abdominal compartment syndrome: pathophysiology and definitions

"Intra-abdominal hypertension", the presence of elevated intra-abdominal pressure, and "abdominal compartment syndrome", the development of pressure-induced organ-dysfunction and failure, have been increasingly recognized over the past decade as causes of significant morbidity and mortality among critically ill surgical and medical patients. Elevated intra-abdominal pressure can cause significant impairment of cardiac, pulmonary, renal, gastrointestinal, hepatic, and central nervous system function. The significant prognostic value of elevated intra-abdominal pressure has prompted many intensive care units to adopt measurement of this physiologic parameter as a routine vital sign in patients at risk. A thorough understanding of the pathophysiologic implications of elevated intra-abdominal pressure is fundamental to 1) recognizing the presence of intra-abdominal hypertension and abdominal compartment syndrome, 2) effectively resuscitating patients afflicted by these potentially life-threatening diseases, and 3) preventing the development of intra-abdominal pressure-induced end-organ dysfunction and failure. The currently accepted consensus definitions surrounding the diagnosis and treatment of intra-abdominal hypertension and abdominal compartment syndrome are presented.