Hyperamylasemia after cardiac surgery. Incidence, significance, and management

Non-pancreatic hyperlipasemia: A puzzling clinical entity

BACKGROUND

Increased lipase level is a serological hallmark of the diagnosis of acute pancreatitis (AP) but can be detected in various other diseases associated with lipase leakage due to inflammation of organs surrounding the pancreas or reduced renal clearance and/or hepatic metabolism. This non-pancreatic hyperlipasemia (NPHL) is puzzling for attending physicians during the diagnostic procedure for AP. It would be clinically beneficial to identify the clinical and laboratory variables that hinder the accuracy of lipase diagnosis with the aim of improve it. A more precise description of the NPHL condition could potentially provide prognostic factors for adverse outcomes which is currently lacking.

AIM

To perform a detailed clinical and laboratory characterization of NPHL in a large prospective patient cohort with an assessment of parameters determining disease outcomes.

METHODS

A Hungarian patient cohort with serum lipase levels at least three times higher than the upper limit of normal (ULN) was prospectively evaluated over 31 months. Patients were identified using daily electronic laboratory reports developed to support an ongoing observational, multicenter, prospective cohort study called the EASY trial (ISRCTN10525246) to establish a simple, easy, and accurate clinical scoring system for early prognostication of AP. Diagnosis of NPHL was established based on ≥ 3 × ULN serum lipase level in the absence of abdominal pain or abdominal imaging results characteristic of pancreatitis.

RESULTS

A total of 808 patients [male, n = 420 (52%); median age (IQR): 65 (51-75) years] were diagnosed with ≥ 3 × ULN serum lipase levels. A total of 392 patients had AP, whereas 401 had NPHL with more than 20 different etiologies. Sepsis and acute kidney injury (AKI) were the most prevalent etiologies of NPHL (27.7% and 33.2%, respectively). The best discriminative cut-off value for lipase was ≥ 666 U/L (sensitivity, 71.4%; specificity, 88.8%). The presence of AKI or sepsis negatively affected the diagnostic performance of lipase. NPHL was associated with a higher in-hospital mortality than AP (22.4% vs 5.1%, P < 0.001). In multivariate binary logistic regression, not lipase but increased amylase level (> 244 U/L) and neutrophil-to-lymphocyte ratio (NLR) (> 10.37, OR: 3.71, 95%CI: 2.006-6.863, P < 0.001), decreased albumin level, age, and presence of sepsis were independent risk factors for in-hospital mortality in NPHL.

CONCLUSION

NPHL is a common cause of lipase elevation and is associated with high mortality rates. Increased NLR value was associated with the highest mortality risk. The presence of sepsis/AKI significantly deteriorates the serological differentiation of AP from NPHL.

Incidence and risk factors of postoperative hyperamylasemia and pancreatitis following total knee arthroplasty: a retrospective study

BACKGROUND

Postoperative hyperamylasemia and pancreatitis are recognized complications after abdominal and spinal surgeries. The aim of this study is to investigate the incidence and identify risk factors for postoperative hyperamylasemia and pancreatitis following total knee arthroplasty.

METHODS

170 patients undergoing total knee arthroplasty were retrospectively identified from our database from January 2017 to January 2021. Patients were divided into normal and hyperamylasemia groups based on the presence of serum amylase level within or greater than the normal range. The diagnosis of postoperative pancreatitis was based on the 2012 revised Atlanta Classification of Acute Pancreatitis. Patient demographics, perioperative parameters were investigated with student t test, chi square test and multivariate logistic regression analysis.

RESULTS

43 patients (25.3%) exhibited postoperative hyperamylasemia while eight patients (4.7%) exhibited serum amylase < 5 times the normal upper limit. One patient (0.6%) was designated as having postoperative pancreatitis. More patients with Hypertriglyceridemia (HTG) were noted in hyperamylasemia group (P = 0.009) compared with normal group. Hyperamylasemia group showed higher preoperative serum amylase (74.95 vs. 55.62 IU/L, P < 0.001), higher intra-operative blood loss (IBL) (117.67 vs. 77.01 mL, P = 0.040) and longer surgical duration (132.98 vs. 107.01 min, P = 0.041). Multivariate logistic analysis revealed that HTG (OR = 0.189, P = 0.006), preoperative serum amylase (OR = 1.042, P < 0.001) and IBL (OR = 1.004, P = 0.022) were independent risk factors for postoperative hyperamylasemia.

CONCLUSIONS

A significant percentage of patients developed hyperamylasemia after total knee arthroplasty. Patients with HTG, higher preoperative serum amylase and higher IBL had an increased risk of developing postoperative hyperamylasemia and pancreatitis.

Heart Failure and Pancreas Exocrine Insufficiency: Pathophysiological Mechanisms and Clinical Point of View

Heart failure is associated with decreased tissue perfusion and increased venous congestion that may result in organ dysfunction. This dysfunction has been investigated extensively for many organs, but data regarding pancreatic (exocrine) dysfunction are scarce. In the present review we will discuss the available data on the mechanisms of pancreatic damage, how heart failure can lead to exocrine dysfunction, and its clinical consequences. We will show that heart failure causes significant impairment of pancreatic exocrine function, particularly in the elderly, which may exacerbate the clinical syndrome of heart failure. In addition, pancreatic exocrine insufficiency may lead to further deterioration of cardiovascular disease and heart failure, thus constituting a true vicious circle. We aim to provide insight into the pathophysiological mechanisms that constitute this reciprocal relation. Finally, novel treatment options for pancreatic dysfunction in heart failure are discussed.

Impact of abdominal imaging on the diagnosis of acute pancreatitis in patients with painless lipase elevation

Abdominal pain is considered a cardinal feature of acute pancreatitis (AP), and abdominal imaging is only required to diagnose AP when the pain is atypical, or serum enzyme elevation does not match the clinical picture. While painless lipase elevation is being increasingly associated with worse outcomes in various diseases, the diagnostic approach to such elevation is so-far unclear. We thus aimed to learn the impact of pain on the diagnosis of AP.

METHODS

All patients presenting to the Mayo Clinic Arizona Hospital emergency department with a serum lipase ≥3x upper limit of normal between April 2016 and January 2020 were prospectively followed. Their charts were reviewed for the nature of pain, serum lipase levels on presentation, abdominal imaging, and whether a diagnosis of AP was made. Chronic pancreatitis was excluded.

RESULTS

Among 320 patients, 85 (26.5%) had painless lipase elevation. These patients had abdominal imaging less often (56/85, 66%) than in those with abdominal pain (201/235, 83%; p = 0.001). The diagnosis of AP increased overall from 31/63 (49%) without imaging to 198/257 (77%) with imaging (P < 0.001). Imaging increased the diagnosis of AP in patients with painless lipase elevation from 2/29 (7%) without imaging to 16/56 (29%; p = 0.025) among those who were imaged.

CONCLUSIONS

Painless lipase elevation >3-fold the upper limit of normal is common in emergency department patients. 1/3 to 1/4 of these may have AP. Abdominal imaging increases the diagnosis of AP in patients with painless lipase elevation. Therefore, abdominal imaging in such patients may help detect AP that otherwise eludes diagnosis.

Adipose saturation reduces lipotoxic systemic inflammation and explains the obesity paradox

Obesity sometimes seems protective in disease. This obesity paradox is predominantly described in reports from the Western Hemisphere during acute illnesses. Since adipose triglyceride composition corresponds to long-term dietary patterns, we performed a meta-analysis modeling the effect of obesity on severity of acute pancreatitis, in the context of dietary patterns of the countries from which the studies originated. Increased severity was noted in leaner populations with a higher proportion of unsaturated fat intake. In mice, greater hydrolysis of unsaturated visceral triglyceride caused worse organ failure during pancreatitis, even when the mice were leaner than those having saturated triglyceride. Saturation interfered with triglyceride's interaction and lipolysis by pancreatic triglyceride lipase, which mediates organ failure. Unsaturation increased fatty acid monomers in vivo and aqueous media, resulting in greater lipotoxic cellular responses and organ failure. Therefore, visceral triglyceride saturation reduces the ensuing lipotoxicity despite higher adiposity, thus explaining the obesity paradox.

Pancreatic Blood Flow with Special Emphasis on Blood Perfusion of the Islets of Langerhans

The pancreatic islets are more richly vascularized than the exocrine pancreas, and possess a 5- to 10-fold higher basal and stimulated blood flow, which is separately regulated. This is reflected in the vascular anatomy of the pancreas where islets have separate arterioles. There is also an insulo-acinar portal system, where numerous venules connect each islet to the acinar capillaries. Both islets and acini possess strong metabolic regulation of their blood perfusion. Of particular importance, especially in the islets, is adenosine and ATP/ADP. Basal and stimulated blood flow is modified by local endothelial mediators, the nervous system as well as gastrointestinal hormones. Normally the responses to the nervous system, especially the parasympathetic and sympathetic nerves, are fairly similar in endocrine and exocrine parts. The islets seem to be more sensitive to the effects of endothelial mediators, especially nitric oxide, which is a permissive factor to maintain the high basal islet blood flow. The gastrointestinal hormones with pancreatic effects mainly influence the exocrine pancreatic blood flow, whereas islets are less affected. A notable exception is incretin hormones and adipokines, which preferentially affect islet vasculature. Islet hormones can influence both exocrine and endocrine blood vessels, and these complex effects are discussed. Secondary changes in pancreatic and islet blood flow occur during several conditions. To what extent changes in blood perfusion may affect the pathogenesis of pancreatic diseases is discussed. Both type 2 diabetes mellitus and acute pancreatitis are conditions where we think there is evidence that blood flow may contribute to disease manifestations. © 2019 American Physiological Society. Compr Physiol 9:799-837, 2019.

Incidence and Risk Factors of Acute Pancreatitis After Scoliosis Surgery: A Prospective Study

STUDY DESIGN

A prospective study.

OBJECTIVE

To investigate the incidence and risk factors of acute pancreatitis after scoliosis surgery.

SUMMARY OF BACKGROUND DATA

Pancreatitis has been recognized as a possible complication of extra-abdominal surgeries. However, there were few reports on the incidence and risk factors of acute pancreatitis after scoliosis surgery.

METHODS

A prospective clinical study was performed at our center from September 2014 to October 2015. One hundred seventy-six patients undergoing posterior spinal correction surgery were enrolled. The diagnosis of acute pancreatitis was based on their clinical manifestations combined with laboratory examination. Demographic, intraoperative, and radiological parameters were evaluated to identify the risk factors of acute pancreatitis after scoliosis surgery.

RESULTS

Thirteen patients (7.4%) were diagnosed with acute pancreatitis. Compared with patients without pancreatitis, pancreatitis patients had lower body mass index (BMI) (15.5 vs. 19.5, P = 0.001), larger preoperative Cobb angle of major curve (87.5° vs. 59.2°, P < 0.001), lower correction rate (57.4% vs. 69.0%, P = 0.045), lower intraoperative mean arterial pressure (57.9 mmHg vs. 66.1 mmHg, P < 0.001), and longer fusion levels (13.3 vs. 10.1, P < 0.001). No significant differences were noted with respect to operation time, intraoperative blood loss, or the amount of sagittal profile correction. Furthermore, multivariate logistic analysis revealed that BMI (odds ratio [OR] = 1.542, P = 0.009), lowest intraoperative mean arterial pressure (OR = 1.126, P = 0.039), and segments of fusion (OR = 0.551, P = 0.025) were independent risk factors for postoperative acute pancreatitis. All cases were treated with bowel rest, intravenous fluids, and fasting and completely recovered with 3.3 (2-5) days.

CONCLUSION

The incidence of postoperative acute pancreatitis after scoliosis surgery was 7.4%. The low BMI, lowest intraoperative mean arterial pressure, and long segments of fusion were independent risk factors for acute pancreatitis after scoliosis surgery.

LEVEL OF EVIDENCE

3.

Acute Gastrointestinal Complications after Open Heart Surgery

Retrospective analysis revealed that 24 of 4401 adult patients (0.5%) developed severe gastrointestinal complications after open heart surgery during a 3-year period from January 1995. There were 4 women (17%) and 20 men (83%). Mean age was 61.7 ± 2.02 years. Gastrointestinal bleeding (33.3%), mesenteric ischemia (20.8%), pancreatitis (20.8%), hepatic dysfunction (16.7%), and cholecystitis (16.7%) were the most common complications. Mortality was 41.7% (10 patients). During the same period, mortality in the patients who did not develop gastrointestinal complications was 1.89% (p < 0.0001). Emergency basis, reoperation, combined operations, peripheral vascular disease, diabetes mellitus, chronic lung disease, and impaired left ventricle function were found to be risk factors for the development of postoperative gastrointestinal complications.

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.

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..

The experimental study for efficacy and safety of pancreatic cryosurgery

OBJECTIVE

This study was designed to basic information concerning the efficacy and safety of cryosurgery for pancreatic cancer. Fifteen healthy pigs were used to perform biochemical analysis and histological assessment.

METHODS

Following anesthesia and laparotomy, an argon-helium cryoprobe was inserted into the pancreas. The introduction of argon gas induced a rapid decrease in temperature to -160 degrees C (Group I, 5 pigs) or -110 degrees C (Group II, 5 pigs), respectively, resulting in ice-ball formation of 15-20mm diameter after 5 min. Following freezing, helium gas was circulated in the probe tip to increase the temperature to 10-20 degrees C over 3 min to thaw. The freeze/thaw cycle was then repeated. Group III (3 pigs) had a cryoprobe inserted, but without freezing, and Group IV (2 pigs) included untreated or normal control animals. Levels of serum amylase (AMY), IL-6 and C-RP were measured prior to freezing and for 7 days following the procedure. All pigs were euthanized 7 days post-treatment and pancreases were examined histologically.

RESULTS

Neither hyperaemia, edema or hemorrhage were observed in the un-frozen parts of the pancreas. Histological assessment revealed a significant level of necrosis in the central and lateral regions of the tissue frozen within the ice-ball. All cellular ultrastructure was destroyed and only observable as a few of remaining nuclei with broken crests and degranulated mitochondria and rough endoplasmic reticulum. There was a significant increase of serum AMY levels for a brief period in both "deep frozen" and the "shallow frozen" groups. However, the AMY also increased in two pigs in the "normal control" group and one pig from the "inserted cryoprobe without freeze" control group. All experimental pigs appeared healthy until the sacrifice time.

CONCLUSION

Cryosurgery is a safe and effective ablative procedure for pancreatic tissue resulting in minimal complications.

Postoperative Care of the Cardiac Surgical Patient

The subspecialty of interventional cardiology began in 1977. Since then, the discipline of interventional cardiology has matured rapidly, particularly with regards to ischemic heart disease. As a result, more patients are undergoing percutaneous catheter interventional therapy for ischemic heart disease and fewer patients are undergoing surgical myocardial revascularization. Those patients referred for surgical revascularization are generally older and have more complex problems. Furthermore, as the population ages more patients are referred to surgery for valvular heart disease. The result of these changes is a population of surgical patients older and sicker than previously treated.

Elevated serum pancreatic enzyme levels after hemorrhagic shock predict organ failure and death

BACKGROUND

Intraluminal pancreatic enzymes have been shown in animal models to be associated with multiple organ failure after hemorrhagic shock, independent of pancreatitis. The translocation of these enzymes into the circulation may serve as a marker of hemorrhagic shock-induced gut ischemia in critically injured trauma patients. We hypothesized that serum amylase and lipase would be significantly elevated in patients presenting in hemorrhagic shock and in those who develop organ failure.

METHODS

: Review of a prospective database at a level-1 trauma center from 2000 to 2005. Two thousand seven hundred eleven critically injured trauma patients without pancreatic injuries were evaluated for shock (systolic pressure <90 mm Hg in the emergency department), massive transfusion (10 units of packed red blood cells within the first 24 hours), and organ failure (standard criteria for acute pulmonary, cardiovascular, renal, and hepatic system failure were used). Serum levels >2 times the upper limit of normal for amylase (30-130 U/L) and lipase (7-60 U/L) were defined as elevated. Univariate analyses were performed with the Pearson's chi, and binary logistic regression was used to determine significant risk factors for organ failure. Results with a p value <0.05 were considered significant and are reported.

RESULTS

: Patients with elevated amylase (n = 481, 18%) were more likely to present in shock (16% vs. 8%), require massive transfusion (19% vs. 9%), develop organ failure (34% vs. 16%), and die (23% vs. 13%). Patients with elevated lipase (n = 288, 11%) were more likely to require massive transfusion (18% vs. 10%) and develop organ failure (43% vs. 16%). Independent predictors of organ failure were age (odds ratio [OR] = 1.016), Injury Severity Score (OR = 1.02), massive transfusion (OR = 3.1), elevated amylase (OR = 1.9), and elevated lipase (OR = 3.2). Elevated amylase was also an independent predictor of mortality (OR = 1.3).

CONCLUSIONS

: Serum levels of pancreatic enzymes are elevated in patients who present in shock or require a massive transfusion and are independent predictors of organ failure. Whether these elevations are caused by ischemic pancreatitis or the translocation of intraluminal enteric pancreatic enzymes is uncertain and future studies are needed. Trauma patients with elevated pancreatic enzymes in the absence of a pancreatic injury have an increased risk of morbidity and mortality.

Incidence of Postoperative Pancreatic Fistula and Hyperamylasemia after Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy

INTRODUCTION

The purpose of this study was to analyze the postoperative pancreatic morbidity of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of peritoneal surface malignancies (PSM).

PATIENTS AND METHODS

Two hundred and sixty five patients (87M/178F) with PSM underwent 270 consecutive procedures. The mean age was 52 years (range: 22-79 years). CRS was performed using peritonectomy procedures. HIPEC through the closed abdomen technique was conducted using cisplatin (CDDP 25 mg/m2/L of perfusate)+mitomycin C (MMC 3.3 mg/m2/L of perfusate) or CDDP (43 mg/L of perfusate)+doxorubicin (Dx 15.25 mg/L of perfusate), at 42.5 degrees C. Diagnosis and classification of postoperative pancreatic fistula (POPF) were performed according to the international study group on pancreatic fistula criteria. Serum amylase alterations were graded according to the National Cancer Institute (NCI) common terminology criteria for adverse events (CTCAE) v3.

RESULTS

POPF was observed in 13 (4.8%) cases. Three cases were classified as major (grade C). Two cases presented postoperative pancreatitis. G3-4 alteration of amylase was observed in 12.3% of the cases. Performing splenectomy and CDDP dosage for HIPEC >240 mg were proven to be independent risk factors for both G3-4 hyperamylasemia and POPF.

CONCLUSIONS

CRS+HIPEC presented an acceptable rate of pancreatic morbidity which did not contribute to the mortality related to the procedure. Most of the POPF were mild and/or easily controlled by conservative measures. Although not specific a normal amylasemia could be a useful marker of pancreatic integrity after CRS+HIPEC.

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.

Detection of postoperative pancreatitis after pancreatic surgery by urine trypsinogen strip test

Background

The urine trypsinogen strip test has been used successfully in the diagnosis of pancreatitis of various aetiologies, but has not been studied in postoperative pancreatitis. The aim of this study was to evaluate this test for the diagnosis of postoperative pancreatitis after pancreatic resection.

Methods

Fifty patients undergoing pancreatic resection were included. The urine trypsinogen strip test was done daily during the first postoperative week, blood was analysed before and 4, 6 and 10 days after surgery, and amylase activity in the drainage fluid was measured on days 4 and 6. Patients underwent computed tomography (CT) before operation and on days 2 and 6 afterwards.

Results

Thirteen patients (26 per cent) developed CT-detected pancreatitis after operation. In 12 of these patients pancreatitis was detected on the second postoperative day. The urine trypsinogen test was positive in all 13 patients with postoperative pancreatitis, and was already positive on the first day after surgery in 12. The sensitivity, specificity, and positive and negative predictive values of the trypsinogen strip test in detection of postoperative pancreatitis were 100, 92, 81 and 100 per cent respectively. In receiver–operator characteristic analysis the area under the curve (AUC) was higher for the urine trypsinogen strip test (AUC 0·959) than for a serum amylase level more than two (AUC 0·731) or three times (AUC 0·654) above the upper normal range in the diagnosis of postoperative pancreatitis. Patients whose recovery was complicated by pancreatic fistula, detected by drain output measurements on day 6, more often had a positive urine trypsinogen test than patients without a fistula (11 of 12 versus five of 38; P &lt; 0·001).

Conclusion

This study suggests that the urine trypsinogen strip test might be a valuable method for diagnosis of pancreatitis after pancreatic surgery.

Disturbances of the microcirculation in acute pancreatitis

BACKGROUND

Severe acute pancreatitis is characterized by pancreatic necrosis, resulting in local and systemic inflammation. Pancreatitis affects both the systemic and pancreatic vasculature. This review focuses on the underlying processes involved in the changes of microvascular anatomy following acute pancreatitis.

METHODS

A Medline/PubMed search (January 1966 to December 2005) with manual cross-referencing was conducted. All relevant articles investigating the pancreatic microcirculatory anatomy and the effect of pancreatitis on the microcirculation were included.

RESULTS

The pancreas is susceptible to ischaemic insult, which can exacerbate acute pancreatitis. There is also increasing evidence of pancreatic and systemic microvascular disturbances in the pathogenesis of pancreatitis, including vasoconstriction, shunting, inadequate perfusion, and increased blood viscosity and coagulation. These processes may be caused or exacerbated by ischaemia-reperfusion injury and the development of oxygen-derived free radicals.

CONCLUSION

Acute pancreatitis impairs the pancreatic and systemic microcirculation, which is a key pathological process in the development of severe necrotizing disease.

Risk factors and outcomes of pancreatitis after open heart surgery

BACKGROUND

We sought to analyze the risk factors and natural history associated with post-cardiac surgery acute pancreatitis.

METHODS

Retrospective analysis of all patients having undergone cardiac surgery at our hospital between January 1, 1992, and October 1, 2001.

RESULTS

A total of 10,249 cardiac operations were performed. Thirty-nine (0.4%) patients developed postoperative pancreatitis. There was a higher incidence during the period spanning 1992 through 1996 than 1997 through 2001 (0.6% versus 0.2%, P< .05). Patients with pancreatitis had longer postoperative length of stay (51+/-5 days versus 10+/-1 days, P<.05) and a greater in-hospital mortality rate (28% versus 4%, P<.05) than patients who did not develop pancreatitis. A history of alcohol abuse, cardiac surgery performed during 1992 to 1996, increased cardiopulmonary bypass time, and increased cross-clamp time were independent risk factors for the development of pancreatitis. Multiple-organ failure was an independent predictor for death among patients with pancreatitis.

CONCLUSIONS

Although the frequency of post-cardiac surgery pancreatitis is diminishing, it is still associated with significant mortality.

Clinical significance of increased lipase levels on admission to the ICU

STUDY OBJECTIVES

To examine the incidence, risk factors, and sequelae associated with asymptomatic hyperlipasemia in the ICU.

SETTING

Medical and surgical ICUs.

PATIENTS

Two hundred forty-five adult critically ill patients admitted to an ICU for > 72 h with a diagnosis other than pancreatitis were studied prospectively.

MEASUREMENTS

Serum amylase and lipase were measured on ICU admission and every third day until normalized. Clinical parameters including the incidence of ileus, the ability to tolerate enteral feeds, and the results of radiologic studies were also recorded.

RESULTS

Hyperlipasemia was present in 40% of patients (peak, 1,183 +/- 175 U/L; range, 209 to 8,620 U/L) [mean +/- SEM]. Increased multiple-organ dysfunction scores, hypotension, anemia, mechanical ventilation (MV), bacteremia, elevated liver function test results, and elevated creatinine and triglyceride levels were all associated with increased lipase levels. In multivariate analysis, hypotension, anemia, elevated serum bilirubin, and MV were independently associated with higher lipase levels. Although mortality was not different, ICU length of stay and the duration of MV were significantly greater in patients with increased lipase levels (p < 0.05). Fifty patients underwent imaging studies. Pancreatitis was confirmed in 11 patients. The mean peak lipase value was significantly increased in patients with a positive study finding as compared to those with negative findings: 2,231 +/- 715 U/L and 900 +/- 234 U/L, respectively (p < 0.01). Enteral feedings, when initiated, were tolerated in 94% of patients with increased lipase levels and 97% of patients with normal lipase levels.

CONCLUSIONS

Elevated serum lipase levels are frequently encountered in critically ill patients. In the majority of these patients, enteral feedings are well tolerated and there are minimal clinical sequelae. Extremely high lipase levels may be associated with radiologic evidence of pancreatitis. Hypoperfusion and inflammatory processes associated with multiple-organ failure appear to be contribute to these increases.

Abdominal organ injury after cardiac surgery

Gastrointestinal complications occur in about 2.5% of patients undergoing cardiac surgery, are associated with a high mortality (about 33%), and account for nearly 15% (and perhaps increasing) of all postoperative deaths. The various complications and risk factors are reviewed. Splanchnic ischemia prior to, during, and especially postoperatively appears to be an important cause of these complications. In addition, splanchnic ischemia is hypothesized to be one cause of the systemic inflammatory response syndrome and multiorgan failure that may follow cardiac surgery. The physiology of splanchic perfusion and the effects of cardiac surgery, including cardiopulmonary bypass, on it are reviewed. Finally, possible methods to minimize splanchnic ischemia and reduce the incidence of abdominal complications are discussed.

Acute pancreatitis following liver resection: report of three fatal cases and a review of the literature

Pancreatitis is a well recognised but rare complication following liver resection. The precise aetiology is not well understood and the clinical diagnosis may frequently be obscured by the postoperative state. Postoperative pancreatitis has a high mortality rate and should always be considered in patients who unexpectantly deteriorate postoperatively. We present three fatal cases of pancreatitis following liver resection. The literature is reviewed to elucidate common factors in patients who develop postoperative pancreatitis.

Use of an oxygen therapeutic as an adjunct to intraoperative autologous donation to reduce transfusion requirements in patients undergoing coronary artery bypass graft surgery1 1Members of the Hemolink Study Group are listed in Appendix

BACKGROUND

The benefits of intraoperative autologous donation (IAD) in reducing the need for allogeneic blood transfusion in surgery have been debated for several years. The purpose of this study was to determine if IAD alone or in conjunction with hemoglobin raffimer (HR) confers a reduction in red cell or blood component transfusion compared with results in standard clinical practice.

STUDY DESIGN

The Phase III clinical trial was a multicenter, randomized, double-blind study to determine the efficacy and safety of HR versus 10% pentastarch when used to facilitate IAD in 299 patients undergoing primary coronary artery bypass grafting. The patients received HR or pentastarch as an adjunct to IAD immediately before cardiopulmonary bypass. Results were compared with transfusion requirements for 150 matched patients in the reference group.

RESULTS

The frequency of allogeneic RBC transfusion in the HR, pentastarch, and reference groups was 56%, 76%, and 95%, respectively. The number of allogeneic red cell units used was 49 in the HR group, 104 in the pentastarch group, and 480 in the reference group (p < 0.001). The total number of non-RBC units administered was 150 in the HR group, 238 in the pentastarch group, and 270 in the reference group.

CONCLUSIONS

In this study, patients treated with HR in conjunction with IAD received fewer transfusions overall and a lower volume of allogeneic RBCs and non-RBC allogeneic blood products than did the two comparison groups. This confers a real benefit on the overall blood supply by decreasing use and increasing availability.

Cytokine release, pancreatic injury, and risk of acute pancreatitis after spinal fusion surgery

Acute pancreatitis after posterior spinal fusion in children is associated with high intraoperative blood loss. Inflammation, oxidative stress, and pancreatitis markers were assessed during this period. Five of the 17 patients studied developed acute pancreatitis 3-7 days after surgery. Intraoperative blood loss (4850 +/- 2315 vs 1322 +/- 617 ml) and peak tumor necrosis factor alpha levels (15.29 +/- 5.3 vs 8.27 +/- 4.6 pg/ml) in the immediate postoperative period were significantly higher in these five patients than in controls, respectively. No differences were noted in serum interleukin 8, interleukin 6, pancreatis-associated protein, or urine malondialdehyde levels. Urine trypsin-associated peptide, elevated initially in all patients, was significantly higher in the acute pancreatitis group at diagnosis. Length of stay was significantly longer in the acute pancreatitis group. Greater blood loss and peak tumor necrosis factor alpha are associated with subsequent risk of acute pancreatitis, suggesting a role of ischemia-reperfusion injury.

Accuracy of diagnostic laparoscopy for early diagnosis of abdominal complications after cardiac surgery

BACKGROUND

In the early postoperative period after major cardiac surgery using extracorporal circulation, abdominal complications can have serious consequences with a mortality rate of up to 70%. Early diagnosis and the timely institution of therapy are the most important factors to improve the outcome; however, clinical evaluation of the abdomen is difficult in these patients. Diagnostic laparoscopy is a minimally invasive procedure with low procedure-associated morbidity, even in critically ill patients. The aims of our study were to investigate the safety of laparoscopy in critically ill patients suspected to have intraabdominal pathology following cardiac surgery and to evaluate the accuracy of diagnostic laparoscopy compared to laparotomy in this setting.

METHODS

A total of 17 patients were included (13 male, four female, age 52-80 years) in the early (3-30 days) postoperative period after cardiac surgery using extracorporal circulation (10 ACVB, four valve replacement, one aorto-coronary-venous-bypass (ACVB)+ valve replacement, two cardiac transplantation). Clinical and laboratory findings included distended abdomen (17 of 17), elevated white blood cells (12 of 17), elevated C-reactive protein (CRP) (13 of 17), and elevated lactate levels (11 of 17). The decision to perform laparotomy was taken in all patients on the basis of their clinical condition. Diagnostic laparoscopy was always performed immediately before laparotomy. The laparoscopic findings were then compared to the laparotomy findings.

RESULTS

In one patient, laparoscopy showed no abnormal findings, this was confirmed on laparotomy. Five patients were found to have massive distension of the large bowel without ischemia on both laparoscopy and laparotomy. Colonic ischemia of the right hemicolon was found laparoscopically in six patients, which was confirmed in all cases by open resection and histological workup. Three patients suffered from acute cholecystitis, which was correctly diagnosed by laparoscopy in all cases. In one patient, laparoscopy revealed fibrinous peritonitis without other findings. Open exploration failed to identify the cause of the peritonitis in this patient. Laparoscopy showed no pathological findings in one patient, but laparotomy then revealed necrotizing pancreatitis confined to the lesser sac. There was one laparoscopy-associated intraoperative complication (6%) in this series.

CONCLUSIONS

Diagnostic laparoscopy is a minimally invasive procedure that can be performed at low intraoperative risk in critically ill patients and has a high sensitivity (94%) for the correct diagnosis of intraabdominal complications after major cardiac surgery. These results suggest that bedside laparoscopy should be considered for all patients with equivocal abdominal symptoms in this setting.

[Abdominal complications associated with cardiac surgery. Review of a contemporary surgical experience and of a series done without extracorporeal circulation]

INTRODUCTION

To evaluate the prevalence, risk factors and morbidity associated with gastrointestinal (GI) complications after cardiac surgery, with and without cardiopulmonary bypass, we carried out a retrospective cohort study at a university teaching hospital.

METHODS

We divided the 11,405 eligible adult patients into 2 groups: group A (operated on between January 1992 and June 1996) (4657 patients) and group B (operated on between July 1996 and December 2000) (6748 patients).

RESULTS

We found 147 GI complications in 134 (1.2%) patients. The incidence of GI morbidity was similar for the 2 groups of patients (group A, n = 59/4657 [1.2%]; group B, n = 75/6748 [1.1%]. Patients from group B were older, obese, diabetic and presented with more peripheral and cerebrovascular disease. Bleeding, gastritis and ulcer with perforation, the most common of these GI events, were associated with the esophagus and stomach (67/147 [45.5%]). Other events that we documented included cholecystitis 10 (6.8%), pancreatitis 13 (8.8%), episodes of small and large bowel ischemia 17 (11.6%), pseudomembranous colitis 12 (8.3%) and diverticulitis 5 (3.4%). Mesenteric ischemia was responsible for 11 (37.9%) of the 29 deaths. Two hundred and ninety-three patients were revascularized without extracorporeal circulation during this study. In this group, we were able to pinpoint 5 (1.7%) GI complications with 3 cases of mesenteric ischemia. Multivariate analysis identified renal insufficiency, prolonged intubation and sepsis as significant, predictive variables of GI complications for the 2 groups of patients whereas the Parsonnet score and stroke were predictive for the second group.

CONCLUSIONS

Although cardiac surgery is now being performed on older patients with significant comorbidity, we could not demonstrate a significant increase of GI complications after cardiac surgery. Off-pump coronary artery bypass does not seem to protect patients from these complications.

[Acute clinical pancreatitis following selective transcatheter arterial chemoembolization of hepatocellular carcinoma]

Acute pancreatitis can complicate non-selective transcatheter arterial embolization of hepatocellular carcinoma with an incidence ranging from 1,7% (acute clinical pancreatitis) to 40% (biological pancreatitis). This complication is thought to be related to embolization of extrahepatic arterial collaterals. We report herein a case of acute clinical pancreatitis developing within 24 hours after a second course of selective transcatheter arterial chemo-embolization into the proper hepatic artery. Neither anatomical arterial variation nor particular risk factor for acute pancreatitis could be identified. This complication is unusual after selective arterial embolization. Because it may clinically mimick a postembolization syndrome, dosage of serum pancreatic enzymes should be performed systematically in case of abdominal pain following chemoembolization.

Is hyperamylasemia after cardiac surgery due to cardiopulmonary bypass?

Although hyperamylasemia has been reported in a large proportion of patients undergoing cardiac surgery with cardiopulmonary bypass, its clinical significance and pathogenetic mechanisms remain poorly understood. The study was designed to investigate whether avoidance of cardiopulmonary bypass would limit amylase elevation. Serum levels of amylase and lipase were measured preoperatively as well as 24 and 48 hours postoperatively in 58 patients undergoing elective coronary artery bypass grafting. Three surgical approaches were used: cardiopulmonary bypass (n = 32) and off-pump through a median sternotomy (n = 14) or a left minithoracotomy (n = 12). There was no hospital mortality or postoperative abdominal complications. Transient hyperamylasemia occurred in 14 patients: 7 (22%), 5 (36%), and 2 (17%) in the respective groups. The increase in amylase levels was similar among the groups. However, no lipase elevation was detected in any patient. There was no clear correlation between hyperamylasemia and increased creatinine levels. Perioperative plasma calcium levels were normal in patients who had hyperamylasemia. Our results indicate that hyperamylasemia after bypass surgery is not related to the use of cardiopulmonary bypass or the mode of surgical access.

Hyperamylasemia and subclinical pancreatitis after cardiac surgery

Hyperamylasemia after cardiac surgery is common but typically causes no clinical concern because it consists mainly of the salivary isoenzyme. In this study we evaluated the incidence, source, and time course of postoperative hyperamylasemia with special attention to the possibility of subclinical pancreatitis. In 88 patients prospectively tested for serum amylase and lipase concentrations, elastase 1 activity, and amylase isoenzyme characteristics, 57 (64%) showed hyperamylasemia during the early postoperative period. In most cases early hyperamylasemia was not of pancreatic origin, but two patients were diagnosed with subclinical pancreatitis. Among the last 23 patients, 5 of 10 patients with early hyperamylasemia exceeding 1000 IU/L showed late hyperamylasemia on the seventh postoperative day, when it represented mainly the pancreatic isoenzyme. Lipase concentrations and elastase 1 activities were elevated in these cases. Late hyperamylasemia following cardiac surgery may be of pancreatic origin and indicative of subclinical pancreatitis, even if early hyperamylasemia was of salivary origin.

Pancreatitis after posterior spinal fusion for adolescent idiopathic scoliosis

A case report describes an adolescent with idiopathic scoliosis who underwent a posterior spinal fusion and developed pancreatitis postoperatively. The patient recovered with parenteral nutrition support. We report this case to add to the literature that supports a benign disease course for postoperative pancreatitis in patients who have had posterior spinal fusion.

Hypotension during ERCP is common but not a risk factor for post-ERCP pancreatitis

BACKGROUND

In patients undergoing cardiopulmonary bypass, hypotension is a risk factor for developing acute pancreatitis. Hypotension in animal models can also induce pancreatitis. We sought to determine whether or not relative hypotension during ERCP is a risk factor for developing acute pancreatitis.

PATIENTS AND METHODS

A nested, case-control study reviewed all cases of post-ERCP pancreatitis resulting from ERCPs performed at this institution between May 1993 and May 1998. Post-ERCP pancreatitis was defined as abdominal pain requiring hospitalisation and elevation of serum amylase or lipase more than four times the upper limit of normal 24 hours or more after ERCP. Non-invasive blood pressure measurements were recorded automatically at least every 5 min during ERCP. Hypotension was defined as any systolic blood pressure (SBP) <100 mmHg, diastolic blood pressure (DBP) <60 mmHg, or mean blood pressure (MBP) <80 mmHg. Controls were chosen randomly from ERCPs performed on the same or the nearest day as each index case.

RESULTS

In total, 1854 ERCPs were reviewed from the study period.There were 96 cases of post-ERCP pancreatitis,giving an incidence of 5.2%. The average age of cases was 48 years, while that of controls was 55 years (p < 0.003).There were no differences between the groups regarding gender, ERCP findings, need for sphincterotomy nor acinar filling on the pancreatogram (acinarisation). At least one episode of hypotension was recorded in 32% of cases and 30% of controls (p = 0.75). There were no differences between cases and controls comparing mean pre- and intra-procedure SBP, DBP and MBPs, or lowest procedure SBP, DBP and MBP.

DISCUSSION

Episodes of acute hypotension are common during ERCP but are not a risk factor for developing post-ERCP pancreatitis.

Etiology and pathogenesis of acute pancreatitis: current concepts

Acute pancreatitis is a disorder that has numerous causes and an obscure pathogenesis. Bile duct stones and alcohol abuse together account for about 80% of acute pancreatitis. Most episodes of biliary pancreatitis are associated with transient impaction of the stone in the ampulla (that causes obstruction of the pancreatic duct, with ductal hypertension) or passage of the stone though and into the duodenum. Other causes of acute pancreatitis are various toxins, drugs, other obstructive causes (such as malignancy or fibrotic sphincter of Oddi), metabolic abnormalities, trauma, ischemia, infection, autoimmune diseases, etc. In 10% of cases of acute pancreatitis, no underlying cause can be identified; this is idiopathic pancreatitis. Occult biliary microlithiasis may be the cause of two thirds of the cases of "idiopathic" acute pancreatitis. Intra-acinar activation of trypsinogen plays a central role in the pathogenesis of acute pancreatitis, resulting in subsequent activation of other proteases causing the subsequent cell damage. Ischemia/reperfusion injury is increasingly recognized as a common and important mechanism in the pathogenesis of acute pancreatitis and especially in the progression from mild edematous to severe necrotizing form. Increased intracellular calcium concentration also mediates acinar cell damage. Oxygen-derived free radicals and many cytokines (e.g., interleukin [IL]-1, IL-6, IL-8, tumor necrosis factor-alpha, platelet activating factor) are considered to be principal mediators in the transformation of acute pancreatitis from a local inflammatory process into a multiorgan illness.

Predictors of gastrointestinal complications in cardiac surgery

Gastrointestinal problems are infrequent but serious complications of cardiac surgery, with high rates of morbidity and mortality. Predictors of these complications are not well developed, and the role of fundamental variables remains controversial. In a retrospective review of our cardiac surgery experience from July 1991 through December 1997 we found that postoperative gastrointestinal complications were diagnosed in 86 of 4,463 consecutive patients (1.9%). We categorized these 86 patients into 2 groups--Surgical and Medical--according to the method of treatment used for their complications. In the Medical group, 9 of 52 patients (17%) died; in the Surgical group, 17 of 34 (50%) died. By logistic multivariate analysis, we identified 8 parameters that predicted gastrointestinal complications: age greater than 70 years, duration of cardiopulmonary bypass, need for blood transfusions, reoperation, triple-vessel disease, New York Heart Association functional class IV, peripheral vascular disease, and congestive heart failure. Postoperative re-exploration for bleeding was a predictor specific to the Surgical group. Use of an intraaortic balloon pump was markedly higher in the Gastrointestinal group than in the Control group (30% vs 10%, respectively), as was the use of inotropic support in the immediate postoperative period (27% vs 5.6%). Our results suggest that intra-abdominal ischemic injury is a likely contributing factor in most gastrointestinal complications. In turn, the ischemia is probably caused by hypoperfusion due to low cardiac output, hypotension due to blood loss, and intra-abdominal atheroemboli. The derived models are useful for identifying patients whose risk of gastrointestinal complications after cardiac surgery may be reduced by clinical measures designed to counter these mechanisms.

The significance of hyperamylasaemia after colonic resection

OBJECTIVE

Colonic resection may be complicated by prolonged post-operative paralytic ileus. Post-operative hyperamylasaemia and pancreatitis may sometimes follow abdominal surgery or occasionally trauma. Post-operative ileus seen after colectomy may be secondary to unrecognized pancreatitis and hyperamylasaemia. The aims of this study were to identify the incidence of hyperamylasaemia after colonic resection, to investigate the effect of hyperamylasaemia on post-operative intestinal function and to correlate any changes with extent of colorectal resection.

PATIENTS AND METHODS

The serum amylase was determined prospectively in a consecutive series of 150 patients who underwent elective colorectal resection. Serum amylase was measured before surgery and post-operatively until it returned to within the normal range.

RESULTS

Hyperamylasaemia occurred in 28 patients (18.7%) after colorectal surgery. Serum amylase levels returned to normal in all but seven patients (4.7%) by the second post-operative day. The development of hyperamylasaemia did not adversely influence the post-operative course. Both groups of patients had similar restoration of intestinal function and were discharged home on equivalent days. Ligation of the middle colic artery alone was found to be significantly associated with hyperamylasaemia by multivariate stepwise logistic regression analysis.

CONCLUSION

Twenty-eight out of 150 patients who underwent colorectal resection developed hyperamylasaemia after surgery. The incidence was highest in patients with middle colic artery ligation. The development of post-operative hyperamylasaemia does not seem to influence adversely the post-operative course in this series.

Acute Pancreatitis after Cardiac Transplantation and Other Cardiac Procedures: Case-Control Analysis in 24,631 Patients

Previous series have identified an increased risk of developing acute postoperative pancreatitis in heart transplant recipients and other cardiac surgical patients, and some suggest that mortality is significantly increased when pancreatitis occurs in the transplant setting. We conducted a retrospective case-control analysis of adult patients undergoing orthotopic heart transplant or other cardiac procedures from April 1985 through June 1996 at our medical center. Specific risk factors for outcome were assessed including low cardiac output, intra-aortic balloon pump usage, exogenous calcium repletion, immunosuppression, cytomegalovirus infection, cholelithiasis, prior pancreatitis, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores. There was a 30-fold increase in the incidence of pancreatitis in the heart transplant group [12 of 394 (3%) vs 27 of 24,237 (0.1%); P < 0.01]. Compared with the nontransplant cardiopulmonary bypass patients, the transplant patients experienced a statistically significant increased incidence of immunosuppression and three or more risk factors. Transplant patients with pancreatitis demonstrated a significant increase in APACHE II scores and the incidence of three or more risk factors compared with their transplant control group. Patients undergoing nontransplant cardiac procedures and developing pancreatitis had significantly increased cross-clamp times, incidence of low cardiac output, APACHE II scores, and incidence of three or more risk factors compared with their nontransplant cohort. In conclusion, there is a significant increase in the incidence of pancreatitis after orthotopic heart transplant compared with other cardiac procedures. Analysis demonstrates the additive effect of multiple individual risk factors. Immunosuppression confers significant additional risk for pancreatitis in the orthotopic heart transplant patient.

[Severe digestive complications after heart surgery using extracorporeal circulation]

PURPOSE

To determine the incidence, circumstances of occurrence and evolution of gastrointestinal complications after cardiac surgery with extracorporeal circulation (ECC).

METHODS

Retrospective chart study of gastrointestinal complications in 6.281 patients undergoing ECC between january 1994 and December 1997.

RESULTS

Sixty patients developed 68 gastrointestinal complications (1%). Complications included: upper gastrointestinal bleeding (n = 23), intestinal ischemia (n = 19), cholecystitis (n = 7), pancreatitis (n = 6), and paralytic ileus (n = 16). The incidence of these complications was low after coronary artery (0.4%) or valvular surgery (0.8%) and high after cardiac transplantation (6%) and after surgery for acute aortic dissection (9%). Compared with a control population, patients with gastrointestinal complication had a higher Parsonnet score (29 +/- 15 vs 13 +/- 12 points; P = 0.002), were more frequently operated upon as an emergency (40/60, 66% vs 1120/6221, 18%; P = 0.01), underwent ECC of longer duration (114 +/- 66 vs 74 +/- 42 min; P = 0.01), and presented more frequently with low cardiac output after surgery (45/60, 75% vs 435/6221, 7%; P = 0.001). The mortality rate after gastrointestinal complications was 52%. The major factor associated with mortality was the occurrence of sepsis (OR = 38.7). Other factors were: renal failure (OR = 7.9), age > 75 yr (OR = 3.5), mechanical ventilation for more than seven days (OR = 2.7), associated cerebral damage (OR = 3.9).

CONCLUSION

Gastrointestinal complications after ECC occur in high risk surgical patients. These complications are frequently associated with other complications leading to a high mortality rate.

Hyperamylasemia after cardiopulmonary bypass: pancreatic cellular injury or impaired renal excretion of amylase?

BACKGROUND

Postoperative hyperamylasemia and even acute pancreatitis are associated with coronary artery bypass grafting (CABG). The mechanism of hyperamylasemia and pancreatic acinar cell damage was studied in 20 patients undergoing CABG.

METHODS

Serial blood and urine samples at eight time points before, during, and 24 hours after the CABG were collected. Salivary and pancreatic isoamylases, the fractional clearance of isoamylases (i.e., relative to creatinine clearance), pancreatic phospholipase A2 (a specific serum marker of pancreatic acinar cell injury), and cystatin C (a sensitive marker of glomerular filtration rate) were measured.

RESULTS

Mild serum hyperamylasemia (300 to 1000 units/L) was found in 11 of 20 (55%) and severe (> 1000 units/L) in 6 of 20 (30%) patients with no signs of clinical acute pancreatitis. Hyperamylasemia occurred from 6 to 24 hours after the CABG and was mainly caused by pancreatic isoamylase. Serum pancreatic phospholipase A2 concentration remained unchanged, which excludes acinar cell damage. Although renal glomerular filtration was normal during CABG as measured by serum cystatin C and creatinine clearance, the fractional clearance of isoamylases decreased.

CONCLUSIONS

The decreased rate of excretion into urine, rather than pancreatic cellular damage, is the major source of hyperamylasemia after CABG.

The acute abdomen in the critically ill patient

The critically ill patient with an acute abdomen represents a great challenge for the surgeon. The physiologic derangement that is associated with the critically ill state both fuels and is fueled by acute abdominal processes. Improvements in critical care and cardiopulmonary bypass technique have allowed for a group of patients to evolve that are susceptible to the complications of prolonged flow states. This article focuses on the abdominal consequences of support of the critically ill patient, as well as, the diagnostic and therapeutic options that are available to treat these patients.

Regional perfusion abnormalities with phenylephrine during normothermic bypass

BACKGROUND

Hypotension and vasopressors during cardiopulmonary bypass may contribute to splanchnic ischemia. The effect of restoring aortic pressure on visceral organ, brain, and femoral muscle perfusion during cardiopulmonary bypass by increasing pump flow or infusing phenylephrine was examined.

METHODS

Twelve anesthetized swine were stabilized on normothermic cardiopulmonary bypass. After baseline measurements, including regional blood flow (radioactive microspheres), aortic pressure was reduced to 40 mm Hg by decreasing the pump flow. Next, aortic pressure was restored to 65 mm Hg either by increasing the pump flow or by titrating phenylephrine. The animals had both interventions in random order.

RESULTS

At 40 mm Hg aortic pressure, perfusion to all visceral organs and femoral muscle, but not to the brain, was significantly reduced. Increasing pump flow improved perfusion to the pancreas, colon, and kidneys. In contrast, infusing phenylephrine (2.4 +/- 0.6 micrograms.kg-1.min-1) increased aortic pressure but failed to improve splanchnic perfusion, so that significant perfusion differences existed between the pump flow and phenylephrine intervals.

CONCLUSIONS

Increasing systemic pressure during cardiopulmonary bypass with phenylephrine causes significantly lower values of splanchnic blood flow than does increasing the pump flow. Administering vasoconstrictors during normothermic cardiopulmonary bypass may mask substantial hypoperfusion of splanchnic organs despite restoration of perfusion pressure.

Postoperative hyperamylasaemia in cardiac surgery

The mechanism of postoperative hyperamylasaemia was studied in 48 patients undergoing coronary artery bypass grafting (CABG). Mild hyperamylasaemia developed in 87% of the patients, and in 10% the serum amylase activity was > 1000 U/l. Serial measurements of serum salivary (S-) and pancreatic (P-) isoamylases indicated that hyperamylasaemia was highest 24 hours after CABG and consisted mainly of P-amylase component. Serum creatinine, creatinine clearance and urinary albumin concentration remained normal after CABG, excluding severe renal damage. The fractional clearance (i.e. relative to creatinine clearance) of P-amylase decreased more than of S-amylase (from 3.6 to 0.9% vs 1.3 to 0.8%). Decreased rate of excretion into urine, rather than pancreatic cellular damage, is the main source of hyperamylasaemia after CABG.

Hyperamylasemia after cardiac surgery in infants and children

OBJECTIVE

This study was conducted to clarify the incidence of hyperamylasemia after cardiac surgery in infants and children.

DESIGN AND PATIENTS

186 infants and children operated on at Children's Hospital. Helsinki, during an 11-month period were enrolled in the study. Serum samples were taken before and on 3 consecutive days after cardiac surgery at the intensive care unit and before discharge from the hospital.

MEASUREMENTS

We measured serum total amylase and serum pancreatic amylase with two different assays (1) reduction of salivary amylase from total amylase activity and (2) measurement of mass concentration with monoclonal antibodies.

RESULTS

Preoperative values for both total amylase and pancreatic isoenzymes were strongly age-related. At least one of the three tests showed postoperative hyperamylasemia (> +/- 2 SD above starting values of the age group and maximal value > 3 times the individual starting value) in 64/186 (34%) patients. 22/186 (12%) patients had abnormal results in all assays. A more than tenfold rise in pancreatic amylase, suggesting pancreatitis, was found in 14 patients (8%). Mortality was 21% in this subgroup, but 5% in the rest of the patients. Hyperamylasemia was more common after 1 year of age, and after open-heart surgery, especially homograft implantation or cardiac transplantation.

CONCLUSIONS

Hyperamylasemia is a common finding after cardiac surgery in pediatric patients. Amylase isoenzyme measurements are needed for clinical decision making. Age-group-related reference values are mandatory for the right interpretation of amylase values.

Influence of severe underlying pathology and hypovolemic shock on the development of acute pancreatitis in children

Acute pancreatitis in children is a little known and poorly defined disease, and thus rarely considered in the diagnosis of pediatric abdominal pain. In the past 14 years, the authors treated 21 children who had acute pancreatitis. Trauma was the cause of the disease in 29% of the patients. One third (33%) had hypovolemic shock-related pancreatitis (mostly after either cardiopulmonary bypass or severe gastrointestinal bleeding). Furthermore, a major proportion (38%) had severe underlying organic disease. The clinical presentation was unremarkable; most patients (83%) had abdominal pain, especially in the epigastrium, and vomiting was the only other clinical sign exhibited by more than 50%. The Glasgow score (a severity grading system based on eight laboratory values and calculated within the first 48 hours after admission) had good specificity but poor sensitivity. Amylasemia had no predictive value. More than half our patients (57%) had complications, mainly pseudocysts (24%) and relapse (14%), and about one quarter (24%) had severe pancreatitis. There were two deaths (10%), and all surviving children (90%) eventually were symptom-free. Treatment was conservative in the majority of cases; eight patients (38%) required surgery. Hypovolemic shock and a severe underlying pathology were identified as risk factors for the occurrence of severe pancreatitis (P < .005) or death (P < .001), but not for the development of complications.

Trypsinogen is not activated during cardiac surgery with extracorporeal circulation

Amylase, immunoreactive cationic trypsin(ogen) and complexes of cationic trypsin and alpha 1-proteinase inhibitor were analysed in plasma samples from 41 patients following cardiac surgery with extracorporeal circulation. Postoperative hyperamylasaemia was seen in seven patients (17%). In 10 patients there were elevated levels (> 100 micrograms 1(-1)) of immunoreactive cationic trypsin(ogen) on the first postoperative day. After gelfiltration, samples from these 10 patients were analysed for trypsin-alpha 1-proteinase inhibitor complexes, with a solid-phase, double-antibody enzyme-linked immunoassay. The median preoperative level of trypsin-alpha 1-proteinase inhibitor complexes was 4.5 micrograms 1(-1) (range 3.3-11.9) and the median value on the first postoperative day was 5.5 micrograms 1(-1) (range 2.6-14). The ratio between complexes and immunoreactive trypsin(ogen) decreased (p < 0.05) showing that activation of trypsinogen did not occur. This fact argues against the development of protease-mediated subclinical pancreatitis during cardiac surgery with extracorporeal circulation.