Gastrointestinal complications in patients undergoing heart operation: an analysis of 8709 consecutive cardiac surgical patients

Mesenteric ischaemia following cardiac surgery: the influence of intraoperative perfusion parameters

OBJECTIVES

Mesenteric ischaemia (MesI) remains a rare but lethal complication following cardiac surgery. Previously identified risk factors for MesI mortality (age, poor left ventricular (LV) function, cardiopulmonary bypass time and blood loss) are non-specific and cannot necessarily be modified. This study aims to identify potentially modifiable risk factors for MesI mortality through analysis of peri- and intraoperative perfusion data.

METHODS

Patients who underwent cardiac surgery between 2006 and 2011 at Papworth Hospital were retrospectively divided into 3 outcome categories: death caused by MesI; death due to other causes and survival to discharge. A published MesI risk calculator was used to estimate risk of MesI for each patient and then to create 3 cohorts of matched patients from each outcome group. Pre-, intra- and postoperative variables were collected and conditional logistic regression methods were used to identify parameters associated specifically with MesI deaths after cardiac surgery.

RESULTS

A total of 10 409 patients underwent cardiac surgery between 2006 and 2011. The incidence of MesI was 0.3% (30 patients). Two hundred and sixty-one patients died of non-MesI causes and 10 118 survived. It was possible to identify 25 patients in each group at equivalent risk of MesI. The following parameters were found to be associated with MesI mortality: recent myocardial infarction [odds ratio (OR) 4.98, 95% confidence interval (CI) 1.58-15.71, P = 0.01], standard EuroSCORE (OR 1.12, 95% CI 1.03-1.21, P = 0.01), vasopressor dose on bypass (OR 1.28, 95% CI 1.04-1.57, P = 0.02), metaraminol dose on bypass (OR 1.52, 95% CI 1.12-2.06, P = 0.01) and lowest documented mean arterial pressure (OR 0.90, 95% CI 0.83-0.97, P = 0.01). No other intraoperative perfusion-related parameters (e.g. flow, average activated clotting time or pressure) were associated with MesI mortality.

CONCLUSIONS

Our study not only confirms previously known predictive factors, but also demonstrates a new association between intraoperative vasopressor use and MesI mortality.

Gastrointestinal complications and cardiac surgery

Gastrointestinal (GI) complications are an uncommon but potentially devastating complication of cardiac surgery. The reported incidence varies between .3% and 5.5% with an associated mortality of .3-87%. A wide range of GI complications are reported with bleeding, mesenteric ischemia, pancreatitis, cholecystitis, and ileus the most common. Ischemia is thought to be the main cause of GI complications with hypoperfusion during cardiac surgery as well as systemic inflammation, hypothermia, drug therapy, and mechanical factors contributing. Several nonischemic mechanisms may contribute to GI complications, including bacterial translocation, adverse drug reactions, and iatrogenic organ injury. Risk factors for GI complications are advanced age (>70 years), reoperation or emergency surgery, comorbidities (renal disease, respiratory disease, peripheral vascular disease, diabetes mellitus, cardiac failure), perioperative use of an intra-aortic balloon pump or inotrope therapy, prolonged surgery or cardiopulmonary bypass, and postoperative complications. Multiple strategies to reduce the incidence of GI complications exist, including risk stratification scores, targeted inotrope and fluid therapy, drug therapies, and modification of cardiopulmonary bypass. Currently, no single therapy has consistently proven efficacy in reducing GI complications. Timely diagnosis and treatment, while tailored to the specific complication and patient, is essential for optimal management and outcomes in this challenging patient population.

Defining gastrointestinal failure

INTRODUCTION

Gastrointestinal failure (GIF) has been postulated as the motor of multiple organ dysfunction syndrome (MODS) but is not commonly included among other organ failures in scoring systems identifying MODS.

MATERIALS AND METHODS

Relevant articles and published reviews were identified and analyzed through a PubMed search of English language literature on gastrointestinal problems.

RESULTS AND DISCUSSION

Wide variability in terms and definitions was observed. Data on the incidence of GIF and its impact on mortality in critically ill patients are controversial. Very few objectively measurable variables of GI function are available. Most of the definitions of GIF are diagnosis-, but not function-based. Diagnosis-based approach to GIF differs significantly from the function-based assessment of other organ failures and has not justified itself over time.

CONCLUSIONS

There is no consensus on definition of GIF and different medical specialties have different approaches. Development of a proper definition of GIF is warranted.

Gastrointestinal complications following cardiac surgery with cardiopulmonary bypass

Gastrointestinal complications following cardiac surgery with cardiopulmonary bypass include paralytic ileus, stress ulcer, acute ischemic colitis, gastrointestinal bleeding, acute cholecystitis, acute pancreatitis, acute hepatic failure and so on. Due to the lack of diagnostic tests with high specificity and sensitivity, the early diagnosis of these complications is difficult, which leads to a higher mortality rate. Therefore, accurately identifying the risk factors is important for early diagnosis and treatment. The purpose of this paper is to review the pathogenesis, risk factors, diagnosis and treatment of gastrointestinal complications after cardiac surgery with cardiopulmonary bypass.

Surgical Management of Severe Colitis in the Intensive Care Unit

Severe colitis, an umbrella encompassing several entities, is one of the most common acute gastrointestinal disorders resulting in critical illness. Clostridium difficile infection is responsible for the majority of nosocomial diarrhea with fulminant C difficile colitis (CDC) carrying a high mortality. Optimal outcomes can be achieved by early identification and treatment of fulminant CDC, with appropriate surgical intervention when indicated. Ischemic colitis, on the other hand, is uncommon with a range of etiological factors including abdominal aortic surgery, inotropic drugs, rheumatoid diseases, or often no obvious triggering factor. Most cases resolve with nonsurgical management; however, prompt recognition of full-thickness necrosis and gangrene is crucial for good patient outcomes. Fulminant colitis is a severe disease secondary to progressive ulcerative colitis with systemic deterioration. Surgical intervention is indicated for hemorrhage, perforation, or peritonitis and failure of medical therapy to control the disease. Although, failure of medical management is the most common indication, it can be difficult to define objectively and requires a collaborative multidisciplinary approach. This article proposes some simple management algorithms for these clinical entities, with a focus on critically ill patients.

Acute bowel ischemia after heart operations

Acute bowel ischemia is a perioperative complication that is frequently unrecognized as a cause of death after cardiac surgical procedures, with an in-hospital mortality of 50% to 100%. In recent years, controversy regarding the most appropriate approach to resolve clinical or laboratory suspicion and the limited therapeutic options have led to very little improvement in patient prognosis. This article reviews the related literature examining the actual prevalence, pathophysiologic mechanisms, predisposing factors, diagnostic tests, and therapeutic approaches providing a glance at new promising tools in diagnostic workup.

Early laparotomy after lung transplantation: increased incidence for patients with α1-anti-trypsin deficiency

BACKGROUND

Gastrointestinal complications after lung transplantation have been reported with incidence rates ranging from 3% to 51%, but the reasons are poorly understood. We aimed to investigate the correlations between pulmonary diseases leading to lung transplantation and early gastrointestinal complications requiring laparotomy after transplantation with outcomes for patients at increased risk.

METHODS

In this study we performed a retrospective analysis of data of patients who underwent lung transplantation at our institution from 2004 to 2012. The study period was limited to the first 90 days after transplantation.

RESULTS

Lung transplantation was performed in 258 patients, including 51 patients with α1-anti-trypsin deficiency (A1AD). Seventy-eight patients (30%) had an X-ray of the abdomen, and 23 patients (9%) required laparotomy during the first 90 days after transplantation. Patients with A1AD comprised 20% of the total recipients, 23% (18 of 78) of the patients who had an abdominal X-ray performed (p = 0.40), and 48% (11 of 23) of the patients who required laparotomy (p < 0.001). More than 1 of every 5 patients (11 of 51) with A1AD required laparotomy at a median 8 days after transplantation, and the estimated odds ratio for laparotomy for A1AD patients was 5.74 (CI 2.15 to 15.35). In the group of patients with A1AD who required laparotomy, the estimated hazard ratio for death was 1.62 (CI 0.57 to 4.62), the stay in the intensive care unit was prolonged, but no significant difference was observed for time on mechanical ventilation. Among pulmonary diseases and demographics of the patients, no other risk factors were identified for laparotomy.

CONCLUSIONS

A1AD was the only significant risk factor identified for gastrointestinal complications that required laparotomy within 3 months after lung transplantation. There was a trend toward a higher risk of death after laparotomy in patients with A1AD, and the length of stay in the intensive care unit was significantly prolonged, whereas the time on mechanical ventilation was unaffected.

Acute mesenteric ischemia after cardiac surgery: an analysis of 52 patients

OBJECTIVE

Acute mesenteric ischemia (AMI) is a rare but serious complication after cardiac surgery. The aim of this retrospective study was to evaluate the incidence, outcome, and perioperative risk factors of AMI in the patients undergoing elective cardiac surgery.

METHODS

From January 2005 to May 2013, all patients who underwent cardiac surgery were screened for participation, and patients with registered gastrointestinal complications were retrospectively reviewed. Univariate analyses were performed.

RESULTS

The study included 6013 patients, of which 52 (0.86%) patients suffered from AMI, 35 (67%) of whom died. The control group (150 patients) was randomly chosen from among cases undergoing cardiopulmonary bypass (CPB). Preoperative parameters including age (P = 0.03), renal insufficiency (P = 0.004), peripheral vascular disease (P = 0.04), preoperative inotropic support (P < 0.001), poor left ventricular ejection fraction (P = 0.002), cardiogenic shock (P = 0.003), and preoperative intra-aortic balloon pump (IABP) support (P = 0.05) revealed significantly higher levels in the AMI group. Among intra- and postoperative parameters, CPB time (P < 0.001), dialysis (P = 0.04), inotropic support (P = 0.007), prolonged ventilator time (P < 0.001), and IABP support (P = 0.007) appeared significantly higher in the AMI group than the control group.

CONCLUSIONS

Prompt diagnosis and early treatment should be initiated as early as possible in any patient suspected of AMI, leading to dramatic reduction in the mortality rate.

Intestinal ischemia after cardiac surgery: analysis of a large registry

Background

Intestinal ischemia after cardiac surgery is a rare but severe complication with a high mortality. Early surgery can be lifesaving. The aim was to analyze the incidence, outcome, and risk factors for these patients.

Methods

A prospectively collected database with patients who underwent 18,879 cardiac surgical procedures between 1996 and 2011 was investigated. All patients with registered gastrointestinal complications were retrospectively reviewed. Univariate and multivariate analyses were performed to compare patients with and without intestinal ischemia.

Results

Seventeen patients suffered from intestinal ischemia (0.09%), 10 of whom (59%) died. By investigating preoperative parameters independent risk factors were steroids, peripheral vascular disease, cardiogenic shock, and New York Heart Association class 4. When including pre-, per-, and postoperative parameters, only postoperative ones were significant, including elevated creatinine (> 200 μmol/L), prolonged ventilator time, need for intra-aortic balloon pump, and cerebrovascular insult (CVI). The gastrointestinal complications score (GICS) showed a ROC area of 0.87. This was superior compared with EuroSCORE (0.74), to predict intestinal ischemia.

Conclusions

Intestinal ischemia after cardiac surgery is more common in patients with a poor cardiac state, but the use of steroids, peripheral vascular disease, postoperative kidney failure, and CVI were also predictive. GICS score, developed for all GI complications after cardiac surgery, is also of value in predicting this particular complication. The risk factors presented can be used as an aid in the diagnosis of these patients.

Impact of major non-cardiac complications on outcome following cardiac surgery procedures: logistic regression analysis in a very recent patient cohort

OBJECTIVES

In this study, we sought to analyse the incidence of major non-cardiac complications and their impact on survival following cardiac surgery procedures in a contemporary patient cohort. We further determined independent predictors of perioperative mortality and created a logistic regression model for prediction of outcome after the occurrence of these complications.

METHODS

Prospectively collected data of 5318 consecutive adult patients (mean age 68.9±11.0 years; 29.3% [n=1559] female) undergoing cardiac surgery from January 2009 to May 2012 were retrospectively analysed. Outcome measures were six major non-cardiac complications including respiratory failure, dialysis-dependent renal failure, deep sternal wound infection (DSWI), cerebrovascular accident (CVA), gastrointestinal complications (GIC) and sepsis and their impact on perioperative mortality and hospital length of stay using multivariate regression models. The discriminatory power was evaluated by calculating the area under the receiver operating characteristic curves (C statistic).

RESULTS

A total of 1321 complications were observed in 846 (15.9%) patients: respiratory failure (n=432; 8.1%), dialysis-dependent renal failure (n=295; 5.5%), GIC (n=154; 2.9%), CVA (n=151; 2.8%), DSWI (n=146; 2.7%) and sepsis (n=143; 2.7%). Perioperative mortality was 17.0% in patients with at least one major non-cardiac complication and correlated with the number of complications (single, 9.7%; n=53/549; double, 24.0%; n=44/183; ≥3, 41.2%; n=47/114, P<0.001). Six preoperative and four postoperative independent predictors of operative mortality were identified (age (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.3-2.4), peripheral vascular disease (OR 2.6; 95% CI 1.6-4.2), pulmonary hypertension (OR 2.7; 95% CI 1.5-4.9), atrial fibrillation (OR 1.5; 95% CI 1.0-2.3), emergency (OR 5.0; 95% CI 3.4-7.2), other procedures than CABG (OR 1.5; 95% CI 1.0-2.1), postoperative dialysis (OR 4.0; 95% CI 2.6-6.1), sepsis (OR 3.4; 95% CI 2.0-5.6), respiratory failure (OR 3.2; 95% CI 2.2-4.9), GIC (OR 3.2; 95% CI 1.9-5.3)) and included in the logistic model, which accurately predicted outcome (C statistic, 0.892; 95% CI 0.868-0.916). Length of hospital stay was significantly increased according to the number of complications (single: median 15 (IQR 10-24) days, double: 16 (IQR 8-28) days, ≥3: 20 (IQR 13-39) days, P<0.001).

CONCLUSIONS

With a worsening in the risk profile of patients undergoing cardiac surgery, an increasing number of patients develop major complications leading to increased length of stay and mortality, which is correlated to the number and severity of these complications. Our predictive model based on preoperative and postoperative variables allowed us to determine with accuracy the perioperative mortality in critically ill patients after cardiac surgery.

Gastrointestinal complications after open heart surgery: incidence and determinants of risk factors

Acute mesenteric ischemia is a rare but serious complication of open heart surgery. Between January 2009 and January 2012, 1360 adult patients underwent open heart surgery with cardiopulmonary bypass at our institution; 29 patients presented gastrointestinal complications. Eight patients developed acute mesenteric ischemia and all of them died. Significant predictors of the complication were New York Heart Association functional class III/IV, history of extensive atherosclerosis and chronic renal failure, acute renal failure following surgery, low cardiac output, use of 2 or more vasoconstrictor drugs, prolonged mechanical ventilation, and multiorgan failure. Atherosclerosis is a multisystemic disease that affects several organs. Radiologic evaluation of mesenteric arterial system should be performed in high-risk patient populations. Perioperative percutaneous and open vascular procedures will reduce the risk of acute mesenteric ischemia that may develop after cardiac surgery and consequent morbidity and mortality rates.

Clinical implications and risk factors of acute pancreatitis after cardiac valve surgery

PURPOSE

Acute pancreatitis is one of the potentially lethal complications that occurs after cardiac surgery. We tried to identify risk factors for and the prognosis of acute pancreatitis after cardiac valve surgery with cardiopulmonary bypass.

MATERIALS AND METHODS

We retrospectively analyzed a database of consecutive patients who underwent cardiac valve surgery with cardiopulmonary bypass between January 2005 and April 2010 at our institution. Patients were classified as having acute pancreatitis based on serum lipase concentration and clinical symptoms (lipase ≥ 180 U/L or ≥ 60 U/L with relevant symptoms).

RESULTS

Of the 986 patients who underwent cardiac valve surgery with cardiopulmonary bypass, 58 (5.9%) patients developed post-operative pancreatitis. Post-operative hospital stay was significantly longer (29.7 ± 45.6 days vs. 12.4 ± 10.7 days, p = 0.005) and in-hospital mortality rate was higher (15.5% vs. 2.0%, p<0.001) in patients with post-operative pancreatitis than those without. Hypertension, chronic kidney disease, and peri-operative use of norepinephrine were identified as independent risk factors for developing pancreatitis after cardiac valve surgery.

CONCLUSION

We found that acute pancreatitis after cardiac valve surgery requires longer hospitalization and increases the in-hospital mortality rate. Clinicians should be aware that patients could develop pancreatitis after cardiac valve surgery, especially in patients with hypertension and chronic kidney disease treated with norepinephrine.

In-Hospital Nonvariceal Upper Gastrointestinal Bleeding following Cardiac Surgery: Patient Characteristics, Endoscopic Lesions and Prognosis

Background. Nonvariceal upper gastrointestinal bleeding (NVUGIB) can occur following cardiac surgery, with sparse contemporary data on patient characteristics and predictors of outcome in this setting. Aim. To describe the clinical and endoscopic characteristics of patients with NVUGIB following cardiac surgery and characterize predictors of outcome. Methods. Retrospective review of 131 consecutive patients with NVUGIB following cardiac surgery from 2002 to 2005. Demographic characteristics, therapeutic management, and predictors of outcomes were determined. Results. 69.5% were male, mean age: 68.8 ± 10.2 yrs, mean Parsonnet score: 24.6 ± 14.2. Commonest symptoms included melena (59.4%) or coffee ground emesis (25.8%). In-hospital medications included ASA (88.5%), heparin (95.4%, low molecular weight 6.9%), coumadin (48.1%), clopidogrel (22.9%), and NSAIDS (42%). Initial hemodynamic instability was noted in 47.1%. Associated laboratory results included hematocrit 26 ± 6, platelets 243 ± 133 109/L, INR 1.7 ± 1.6, and PTT 53.3 ± 35.6 s. Endoscopic evaluation (122 patients) yielded ulcers (85.5%) with high-risk lesions in 45.5%. Ulcers were located principally in the stomach (22.5%) or duodenum (45.9%). Many patients had more than one lesion, including esophagitis (28.7%) or erosions (26.8%). 48.8% received endoscopic therapy. Mean lengths of intensive care unit and overall stays were 10.4 ± 18.4 and 39.4 ± 46.9 days, respectively. Overall mortality was 19.1%. Only mechanical ventilation under 48 hours predicted mortality (O.R = 0.11; 95% CI = 0.04−0.34). Conclusions. This contemporary cohort of consecutive patients with NVUGIB following cardiac surgery bled most often from ulcers or esophagitis; many had multiple lesions. ICU and total hospital stays as well as mortality were significant. Mechanical ventilation for under 48 hours was associated with improved survival.

Emergency laparoscopic cholecystectomy for a patient with an implantable left ventricular assist device: report of a case

It is not uncommon for cardiac surgery to be complicated by postoperative acute cholecystitis. We recently performed laparoscopic cholecystectomy for severe acute cholecystitis, which developed after the implantation of a left ventricular assist device (LVAD) for dilated cardiomyopathy in a 31-year-old man. The LVAD is an accepted bridging treatment to heart transplantation. With the patient under general anesthesia, we made landmarks around the LVAD and a drive-line to prevent injury by trocar insertion. The first port was inserted in the umbilicus and because the subxyphoid space was occupied, the second trocar was inserted in the left flank and the other two trocars were inserted in the right subcostal area. The operation time was 160 min and the estimated blood loss was 430 ml. The patient had an uneventful postoperative course. Thus, concomitant cholecystectomy should be considered when installing an LVAD system if the patient has biliary abnormalities.

Prevention and treatment of gastrointestinal complications following cardiac surgery with cardiopulmonary bypass

Acute gastrointestinal complications (GICs) following cardiac surgery with cardiopulmonary bypass (CPB) are rare but carry a high mortality rate. During CPB procedures, many factors cause a reduction of blood supply to the digestive system, tissue injury, and the release of many inflammatory mediators, which can lead to GICs such as gastrointestinal bleeding, peptic ulcers, ischemic enteritis, pancreatitis, cholecystitis, and liver failure. Close observation of clinical manifestations and early diagnosis will help timely manage these complications and improve prognosis. The purpose of this paper is to review the mechanism, risk factors, diagnosis and treatment of GICs after cardiac surgery with cardiopulmonary bypass..

Outcome and survival analysis of intestinal ischaemia following cardiac surgery

OBJECTIVES

Intestinal ischaemia is an uncommon (<1%) but serious complication of cardiac surgery with a mortality rate exceeding 50%. Diagnosis of this potentially lethal condition can be difficult and requires a high index of suspicion. The purpose of this study was to analyse the outcomes and prognostic factors in patients who develop intestinal ischaemia following cardiac surgery.

METHODS

In a retrospective review from August 1999 to December 2010, we identified 31 out of 9925 (0.31%) consecutive patients who developed acute intestinal ischaemia following cardiac surgery at our tertiary centre.

RESULTS

The overall mortality was 71.0%. The operative mortality was 65.4% in patients who underwent a laparotomy. Survivors of this complication had surgical intervention earlier (7.4 ± 4.9 h) compared with the non-survivors (13.9 ± 11.1 h). A total of 35 perioperative variables were analysed. A univariate analysis identified 12 variables associated with an increased risk of mortality. Logistic multivariate analysis identified the preoperative logistic EuroSCORE and the base excess at the point of diagnosis of intestinal ischaemia as significant predictors of mortality. These factors may aid prognostication in this group of patients.

CONCLUSIONS

Despite the high mortality rates associated with intestinal ischaemia following cardiac surgery, early diagnosis and surgical intervention remain the only effective means to reduce mortality.

An unusual cause of acute abdominal pain after cardiac surgery: acute epiploic appendagitis

Abdominal complications following cardiac surgery remain unusual, but are associated with high mortality. The most common abdominal surgical complications are mesenteric ischaemia, diverticulitis, pancreatitis, gastrointestinal bleeding and cholecystitis. We describe a case of a 73-year old woman with acute abdominal pain mimicking cholecystitis on day 10 after aortic valve replacement. An abdominal examination showed tenderness of the right upper quadrant with Murphy's sign. Complete blood count, blood chemistries and urinalysis were normal as were the abdominal and chest X-rays and abdominal ultrasonography. The abdominal computed-tomography (CT) scan enabled us to rule out cholecystitis, as it demonstrated the typical appearance of epiploic appendagitis on the right colon, 1 cm below the gallbladder. Epiploic appendagitis results from twisting, kinking or venous thrombosis of an epiploic appendage. Depending on its localization, it mimics many diagnoses requiring surgery: colitis, diverticulitis, appendicitis and cholecystitis. An abdominal CT scan is the diagnostic imaging tool of choice. All physicians involved in post-cardiac surgery care should be aware of this self-limiting disease that usually resolves with non-steroidal anti-inflammatory drugs and watchful waiting, and to avoid unnecessary surgery because the spontaneous evolution of epiploic appendagitis is usually benign.

Acute mesenteric ischemia: a vascular emergency

BACKGROUND

Acute mesenteric ischemia is still fatal in 50% to 70% of cases. This consensus paper was written with the participation of physicians from all of the involved specialties for the purpose of improving outcomes. Mesenteric ischemia must be recognized as a vascular emergency requiring rapid and efficient clinical evaluation and treatment.

METHODS

We reviewed pertinent literature that was retrieved by a PubMed search on the terms "mesenteric ischemia" AND "arterial" OR "venous" OR "clinical presentation" OR "diagnosis" OR "therapy" OR "surgery" OR " interventional radiology." Our review also took account of the existing guidelines of the American College of Cardiology/American Heart Association. Intensive discussions among the participating physicians, representing all of the specialties involved in the management of mesenteric ischemia, led to the creation of this interdisciplinary paper.

RESULTS

Biphasic contrast-enhanced computerized tomography is the diagnostic tool of choice for the detection of arterial or venous occlusion. If non-occlusive mesenteric ischemia is suspected, angiography should be performed, with the option of intraarterial pharmacotherapy to induce local vasodilation. Endovascular techniques have become increasingly important in the treatment of arterial occlusion. Embolic central mesenteric artery occlusion requires surgical treatment; surgery is also needed in case of peritonitis. Portal-vein thrombosis can be treated by local thrombolysis through a transhepatically placed catheter. This should be done within 3 to 4 weeks of the event to prevent later complications of portal hypertension.

CONCLUSION

Rapid diagnosis (within 4 to 6 hours of symptom onset) and interdisciplinary cooperation in the provision of treatment are required if the poor outcome of this condition is to be improved.

Mesenteric ischemia-reperfusion injury: clearly improved hemodynamics but only minor protection of the rat small intestine by (sub)therapeutic heparin sodium and enoxaparin doses

BACKGROUND

Tissue protection against ischemia (I)/reperfusion (R) injury by heparins can be due to their anticoagulant and/or non-anticoagulant properties. Here we studied the protective potential of the anticoagulant and the non-anticoagulant features of heparin sodium (HepSo) and enoxaparin (Enox) against mesenteric I/R injury in a rat model.

MATERIALS AND METHODS

Mesenteric I/R was induced in rats (n = 6 per group) by superior mesenteric artery occlusion (SMAO; 90 min) and reopening (120 min). Therapeutic/clinical and subtherapeutic/non-anticoagulant doses of HepSo (0.25 mg/kg bolus + 0.25 mg/kg × h; 0.05 mg/kg bolus + 0.1 mg/kg × h) or Enox (0.5 mg/kg bolus + 0.5 mg/kg × h; 0.05 mg/kg bolus + 0.1 mg/kg × h) were administered intravenously starting 30 min before SMAO to the end of reperfusion. Systemic/vital and intestinal microcirculatory parameters were measured during the whole experimental procedure, those of small intestine injury at the end.

RESULTS

During intestinal reperfusion, mean arterial blood pressure and heart rates were significantly increased by HepSo and, less effectively, by Enox, in a dose-dependent manner. Intestinal microcirculation was only affected by the therapeutic HepSo dose, which decreased the microvascular flow and S(O2) during reperfusion. The subtherapeutic Enox treatment, as opposed to any HepSo dose, most effectively diminished I/R-induced intestinal hemorrhages, myeloperoxidase activity (as a measure of neutrophil invasion), and histopathological changes.

CONCLUSION

Therapeutic but, to a lesser extent, also the subtherapeutic doses of both HepSo and Enox clearly improve hemodynamics during mesenteric reperfusion, while intestinal protection is exclusively provided by Enox, especially at its subtherapeutic dose. Alterations in intestinal microcirculation are not responsible for these effects. Thus, non-anticoagulant Enox doses and, preferably, heparin(oid)s unable to affect coagulation, could diminish clinical risks of I/R-induced gastrointestinal complications.

Clinical significance of liver ischaemia after pancreatic resection

BACKGROUND

Liver ischaemia after pancreatic resection is a rare but potentially serious complication. The aim of this study was to determine the impact of postoperative liver ischaemia after pancreatic resection.

METHODS

All consecutive patients undergoing pancreatic resection between January 2007 and August 2008 in the Department of Surgery in Heidelberg were identified retrospectively from a prospectively collected database and analysed with a focus on postoperative hepatic perfusion failure. Laboratory data, computed tomography (CT) findings, symptoms, therapy and outcome were recorded.

RESULTS

A total of 762 patients underwent pancreatic resection in the study period. Seventeen patients (2·2 per cent) with a postoperative increase in liver enzymes underwent contrast-enhanced CT for suspected liver perfusion failure. The types of perfusion failure were hypoperfusion without occlusion of major hepatic vessels (6 patients) and ischaemia with arterial (5) and/or portal vein (6) involvement. The overall mortality rate was 29 per cent (5 of 17 patients). Therapy included conservative treatment (7), radiological or surgical revascularization and necrosectomy or resection of necrotic liver tissue (10). Outcome varied from full recovery (4 patients) to moderate systemic complications (6) and severe complications (7) including death. Simultaneous involvement of the portal vein and hepatic artery was always fatal.

CONCLUSION

Postoperative liver perfusion failure is a rare but potentially severe complication following pancreatic surgery requiring immediate recognition and, if necessary, radiological or surgical intervention.

Surgical Procedures for Patients Receiving Mechanical Cardiac Support

Mechanical cardiac support devices are used for patients with cardiopulmonary failure. We reviewed our institutional experience with noncardiac surgical procedures (NCPs) in patients supported by ventricular assist devices (VADs, n = 198) or extracorporeal membrane oxygenation (ECMO, n = 165) between July 1998 and June 2010. In total, 64 NCPs were performed in 55 VAD patients and 14 NCPs in 14 ECMO patients. Thirty-day mortality was higher for the VAD compared with the ECMO group (25 vs 86%; P < 0.001) and was greater for emergent compared with nonemergent procedures (58 vs 19%; P < 0.001). Excluding tracheostomy, no patients died within 30 days of a nonemergent procedure. Kaplan-Meier survival showed a trend toward worse survival after NCP in ECMO patients, but NCP did not alter survival in VAD patients. Fewer VAD patients were bridged to heart transplantation when NCP was required, and time from device implantation to transplant was significantly longer than for patients without NCP. In summary, this is the largest series of NCPs on VAD support and the only series on ECMO. Mortality is substantial for ECMO patients. Selected procedures can be performed safely in VAD patients but will delay heart transplantation.

Exercise-induced splanchnic hypoperfusion results in gut dysfunction in healthy men

Background

Splanchnic hypoperfusion is common in various pathophysiological conditions and often considered to lead to gut dysfunction. While it is known that physiological situations such as physical exercise also result in splanchnic hypoperfusion, the consequences of flow redistribution at the expense of abdominal organs remained to be determined. This study focuses on the effects of splanchnic hypoperfusion on the gut, and the relationship between hypoperfusion, intestinal injury and permeability during physical exercise in healthy men.

Methods and Findings

Healthy men cycled for 60 minutes at 70% of maximum workload capacity. Splanchnic hypoperfusion was assessed using gastric tonometry. Blood, sampled every 10 minutes, was analyzed for enterocyte damage parameters (intestinal fatty acid binding protein (I-FABP) and ileal bile acid binding protein (I-BABP)). Changes in intestinal permeability were assessed using sugar probes. Furthermore, liver and renal parameters were assessed. Splanchnic perfusion rapidly decreased during exercise, reflected by increased gap_g-apCO₂ from −0.85±0.15 to 0.85±0.42 kPa (p<0.001). Hypoperfusion increased plasma I-FABP (615±118 vs. 309±46 pg/ml, p<0.001) and I-BABP (14.30±2.20 vs. 5.06±1.27 ng/ml, p<0.001), and hypoperfusion correlated significantly with this small intestinal damage (r_S = 0.59; p<0.001). Last of all, plasma analysis revealed an increase in small intestinal permeability after exercise (p<0.001), which correlated with intestinal injury (r_S = 0.50; p<0.001). Liver parameters, but not renal parameters were elevated.

Conclusions

Exercise-induced splanchnic hypoperfusion results in quantifiable small intestinal injury. Importantly, the extent of intestinal injury correlates with transiently increased small intestinal permeability, indicating gut barrier dysfunction in healthy individuals. These physiological observations increase our knowledge of splanchnic hypoperfusion sequelae, and may help to understand and prevent these phenomena in patients.

The impact of deep and moderate body temperatures on end-organ function during hypothermic circulatory arrest

OBJECTIVE

Hypothermic circulatory arrest (HCA) at different temperatures is a protection technique for operations involving the aortic arch. In combination with selective cerebral perfusion, higher arrest temperatures for the remaining body may be permitted. However, the ischaemic/reperfusion injury (I/R) in various organ systems, other than the brain, related to the specific HCA temperature has so far not been evaluated.

METHODS

Fourteen pigs were randomly assigned to 60 min of sole HCA at 20 or 30 °C temperature, weaned from cardiopulmonary bypass (CPB) and followed 4h after HCA. Besides complex haemodynamic monitoring, laser-Doppler spectrophotometry for measuring capillary blood flow, tissue oxygen saturation and post-capillary venous filling pressures of the bowel was installed. At the end of experiment, organs were perfusion fixated and harvested.

RESULTS

During the entire experiment, haemodynamics revealed no differences between the groups. CPB bypass times were 177 ± 12 min in the 20 °C and 158 ± 11 min in the 30 °C group, respectively (p = 0.02). During reperfusion, lactate levels were initially significantly higher in the 30 °C animals (p = 0.001) but subsequently declined. Microcirculatory blood flow and velocity in the bowel were significantly reduced during cooling and reperfusion (p < 0.05), but were independent of final HCA temperature. Histological evaluation revealed significantly more oedema formation in the bowel wall of the 30 °C animals (p = 0.05).

CONCLUSIONS

Higher levels of circulating lactate levels during reperfusion indicate less effective organ protection at 30 than at 20 °C after 60 min of HCA. This is further substantiated by histological evidence for a more pronounced oedema inflammatory response within the bowel wall.

Risk factors for gastrointestinal complications in patients undergoing coronary artery bypass graft surgery

OBJECTIVE

To determine the risk factors for the development of gastrointestinal complications (GICs) after coronary artery bypass graft (CABG) surgery.

DESIGN

A single-center, retrospective study.

SETTING

A tertiary care hospital.

PARTICIPANTS

Six thousand seven hundred ninety-four patients undergoing isolated CABG surgery between 2002 and 2006.

INTERVENTIONS

Clinical characteristics of the patients with GICs and control group patients were analyzed by stepwise logistic regression analysis. The control group consisted of a total of 95 patients randomly selected among the ones who had no gastrointestinal finding or symptoms (cohort: control, 1:5 ratio).

MEASUREMENTS AND MAIN RESULTS

Nineteen patients (0.3%) developed major surgical GICs after CABG surgery. Overall, the 30-day mortality was 42.1% among patients with GICs and 2.6% without GICs. Multivariate analysis identified 4 independent predictors for GICs: age greater than 70 years (p = 0.001; odds ratio [OR] = 5.6; 95% confidence interval [CI], 2.1-25.9), reoperation for bleeding (p = 0.005; OR = 7.7; 95% CI, 2.8-56.2), a prolonged cardiopulmonary bypass time (p = 0.007; OR = 3.7; 95% CI, 1.3-15.6), and an increased postoperative creatinine level (p = 0.036; OR = 2.3; 95% CI, 1.1-13.4).

CONCLUSION

A delayed diagnosis of complications is an important problem in the management of major surgical GICs. The present results suggest that surgeons and intensivists must be alert to patients older than 70 years, a cardiopulmonary bypass time longer than 60 minutes, reoperation for bleeding after CABG surgery, and postoperative creatinine level higher than 1.7 mg/dL.

The effect of postoperative gastrointestinal complications in patients undergoing coronary artery bypass surgery

BACKGROUND

Gastrointestinal (GI) complications after coronary artery bypass graft surgery (CABG) are uncommon but associated with a disproportionate share of mortality. We thus identified variables associated with GI complications and analyzed their effect on postoperative mortality in patients undergoing isolated CABG.

METHODS

Information from patients who underwent isolated CABG at our institution during a 12-year period was obtained from the Anesthesiology Institute patient registry. Patients who experienced one or more postoperative GI complication(s) during their initial intensive care unit stay were identified. Multivariable logistic regression with backward variable selection was used to determine variables associated with GI complications and to evaluate their effect on mortality.

RESULTS

Among 16,043 patients who underwent isolated CABG, 213 (1.43%) had one or more GI complication(s). The main patient variables associated with postoperative GI complications included preoperative (odds ratio, 2.43; 95% confidence interval [CI], 1.39 to 4.23; p < 0.001) and intraoperative (odds ratio, 5.07; 95% CI, 3.08 to 8.35; p < 0.001) intraaortic balloon pump insertion, patient age (odds ratio, 1.65; 95% CI, 1.41 to 1.94; p < 0.001), intraoperative fresh-frozen plasma transfusion (odds ratio, 3.38; 95% CI, 2.12 to 5.41; p < 0.001), and cardiogenic shock (odds ratio, 3.04; 95% CI, 1.12 to 8.24). No difference was detected in complication rates between off-pump and on-pump CABG procedures (1.50% versus 1.30%, respectively; p = 0.63). Postoperative GI complication(s) after CABG was associated with a 12.98 times increase in mortality (p < 0.001).

CONCLUSIONS

This single-center cohort study indicates that GI complications after isolated CABG remain rare with an incidence 1.43%. However, GI complications portend a significant mortality. The implications of intraoperative administration of fresh-frozen plasma and insertion of an intraaortic balloon pump deserve further investigation as they are associated with GI complications.

Protection against severe intestinal ischemia/reperfusion injury in rats by intravenous resveratrol

BACKGROUND

Repetitive enteral or intraperitoneal administration of resveratrol at high doses has recently been found to protect the small intestine against acute ischemia/reperfusion (I/R) injury. In the present work, the protective potential of solvent-free continuous intravenous infusions of small amounts of resveratrol was studied in a model of severe intestinal I/R injury.

MATERIALS AND METHODS

Mesenteric ischemia was induced in male Wistar rats (six animals/group) by superior mesenteric artery occlusion (SMAO, 90 min) and reperfusion (120 min) by reopening of the microvascular clamp. Resveratrol (0.056 or 0.28 mg/kg) was continuously perfused into the jugular vein (0.014 or 0.07 mg/kg × h) starting 30 min before SMAO; an SMAO control group and sham groups (no SMAO) receiving either 0.9% NaCl solution or resveratrol (0.28 mg/kg) were included. During the experimental procedure, isotonic saline was given at a systolic blood pressure below 90 mmHg, and several parameters including those of biomonitoring and blood gas analysis were measured. Small intestine injury was assessed macroscopically, from released plasma enzyme activities, from the tissue contents of thiobarbituric acid-reactive substances and hemoglobin, from the tissue myeloperoxidase activity, and histopathologically.

RESULTS

Resveratrol at only 0.056 mg/kg significantly decreased the macroscopic damage score, the tissue myeloperoxidase activity, the hemoglobin content, the histopathologic score, and the plasma glutamate-pyruvate transaminase activity, but it did not improve the systemic and metabolic parameters. Instead, during reperfusion, significantly higher volumes of saline were administered to animals receiving the polyphenol, although resveratrol did not significantly affect any parameters in sham-operated animals.

CONCLUSIONS

Low doses of intravenously administered resveratrol considerably protected the rat small intestine against severe I/R injury, despite some adverse effects on blood pressure under these conditions.

Comparison of two-year outcomes in patients undergoing isolated coronary artery bypass grafting with and without peripheral artery disease

We aimed to evaluate the long-term clinical outcomes among patients with peripheral arterial disease (PAD) after coronary artery bypass grafting. We studied 589 consecutive patients who had undergone isolated coronary artery bypass grafting from January 2003 to June 2005 at our university hospital. The effect of PAD was assessed by comparing the 2-year follow-up data from 2 groups of patients: 243 patients with and 346 without PAD. A large systematic atherosclerosis screening was performed, including cerebrovascular disease, lower extremity artery disease, and abdominal aorta disease and its branches. PAD was defined as a history of treated atherosclerotic disease and significant atherosclerotic stenosis on screening. Patients with PAD were significantly older (70 +/- 9 vs 64 +/- 11 years, p <0.001) and were more often men (p = 0.04) than those without PAD. They had a greater incidence of hypertension (p = 0.002), chronic renal dysfunction (p <0.01), chronic pulmonary disease (p = 0.005), and a history of coronary artery disease (p = 0.03). No significant difference was noted between the 2 groups with regard to the left ventricular ejection fraction. The 2-year cumulative survival rate was 76.6% for patients with PAD and 94.1% for those with isolated coronary disease (p <0.001). In conclusion, after adjusting all significant variables, the presence of PAD appeared as an independent predictive factor for all-cause mortality (adjusted hazard ratio 3.2, 95% confidence interval 1.8 to 5.7, p = 0.001).

Case control study of gastrointestinal complications after cardiopulmonary bypass heart surgery

Background: Gastrointestinal complications (GIC) after cardiopulmonary bypass (CPB) surgery are rare, but, nevertheless, extremely dangerous.The identification of risks for GIC may be helpful in planning appropriate perioperative management strategies. The aim of the present study was to analyze perioperative factors of GIC in patients undergoing CPB surgery. Methods: We retrospectively analysed 206 patients who underwent GIC after cardiopulmonary bypass surgery from 2000 to 2007 and compared them with 206 matched control patients (matched for surgery, temperature, hemodilution and date). Univariate analysis and multiple logistic regression analysis were performed on 12 risk factors. Result: Sex and types of cardioplegia perfusate did not significantly influence the GIC after CPB surgery. Multiple logistic regression revealed that CPB time, preoperative serum creatinine (PSC) ≥ 179 mg/dL, emergency surgery, perfusion pressure ≤40mmHg, low cardiac output syndrome (LCOS), age ≥ 61, mechanical ventilation ≥96 h, New York Heart Association (NYHA) class III and IV were predictors of the occurrence of GIC after CPB surgery. Perfusion pressure and aprotinin administration were protective factors. Conclusion: Gastrointestinal complications after CPB surgery could be predictive in the presence of the above risk factors. This study suggests that GIC can be reduced by maintenance of higher perfusion pressure and shortening the time on CPB and ventilation.

Cardiac anesthesia and surgery in geriatric patients: epidemiology, current surgical outcomes, and future directions

The mean life expectancy of the population of the United States is projected to increase from 78.3 years at present to over 81 years in 2025, with a concomitant increase in the percentage of the population over the age of 75 years. Elderly patients are more likely to present with valvular and coronary artery disease than younger patients, and as better perioperative management contributes to improving post-operative outcomes and lower referral thresholds, very elderly patients form an increasingly large proportion of the cardiac surgical population. This article summarizes the impact of age-related pathophysiologic changes on patients' response to cardiac surgery and anesthesia, outlines useful perioperative strategies in this age group, and reviews the literature on outcomes after valvular and coronary in elderly patients.

Enteral nutrition in the cardiothoracic intensive care unit: challenges and considerations

Cardiovascular disease is a common preexisting condition among hospitalized patients. Acute myocardial infarction and cardiac surgery account for 2 of the most common reasons patients are admitted to the intensive care unit. Determining how and when to feed these patients is a constant challenge presented to nutrition support practitioners. Enteral nutrition has emerged as the preferred route of feeding particularly in critical illness. By providing enteral nutrition instead of parenteral nutrition, the natural physiologic pathway is being followed and gut immunity preserved. However, obstacles such as upper gastrointestinal intolerance, hypoperfusion vasopressor support, and glycemic control make the task of initiating feeds a challenge. Once a patient has successfully tolerated feeds, the nutrition support clinician must still determine how much to feed and if specialty formulas such as those containing omega-3 fatty acids are beneficial for their patient. The purpose of this review is to present recent research on the feeding challenges in the critical care population with a focus on the cardiothoracic population and an emphasis on improving patient outcomes.

Is prompt exploratory laparotomy the best attitude for mesenteric ischemia after cardiac surgery?

Mesenteric ischemia following cardiac surgery is a life-threatening complication. Early identification of patients may help optimizing management and improving outcome. Between January 2000 and July 2007, surgical exploration was realized when mesenteric ischemia was suspected after coronary-artery bypass grafts (CABG). Patients were divided in two groups according to diagnosis confirmation upon laparotomy. Peri-operative predictors of complication and death were analyzed. Of 1634 consecutive patients, 13 (0.8%) developed acute abdomen with suspicion of mesenteric ischemia. Seven (0.4%) underwent resection for ischemic lesions (group 1), of whom two were during a second look laparotomy. The other six patients had normal bowel (group 2). Both groups were comparable according to preoperative status, clinical signs, biological and radiological findings. Delays to laparotomy were 13.7+/-19.0 and 51.4+/-29.0 h in group 1 and 2, respectively (P=0.02). Mortality rates were 46.1% (6/13) overall, 42.8% for group 1 and 50% for group 2. All deaths occurred within the first nine postoperative days. Mesenteric ischemia following CABG is a fatal complication in almost half the cases. Diagnostic tools and timely laparotomy still need to be optimized. Low threshold-based strategy for prompt surgical intervention is efficient for both diagnosis and treatment.

Acute mesenteric ischemia after cardio-pulmonary bypass surgery

Acute mesenteric ischemia (AMI) is a highly-lethal surgical emergency. Several pathophysiologic events (arterial obstruction, venous thrombosis and diffuse vasospasm) lead to a sudden decrease in mesenteric blood flow. Ischemia/reperfusion syndrome of the intestine is responsible for systemic abnormalities, leading to multi-organ failure and death. Early diagnosis is difficult because the clinical presentation is subtle, and the biological and radiological diagnostic tools lack sensitivity and specificity. Therapeutic options vary from conservative resuscitation, medical treatment, endovascular techniques and surgical resection and revascularization. A high index of suspicion is required for diagnosis, and prompt treatment is the only hope of reducing the mortality rate. Studies are in progress to provide more accurate diagnostic tools for early diagnosis. AMI can complicate the post-operative course of patients following cardio-pulmonary bypass (CPB). Several factors contribute to the systemic hypo-perfusion state, which is the most frequent pathophysiologic event. In this particular setting, the clinical presentation of AMI can be misleading, while the laboratory and radiological diagnostic tests often produce inconclusive results. The management strategies are controversial, but early treatment is critical for saving lives. Based on the experience of our team, we consider prompt exploratory laparotomy, irrespective of the results of the diagnostic tests, is the only way to provide objective assessment and adequate treatment, leading to dramatic reduction in the mortality rate.