Acute abdomen in the hemodialysis patient population

Early endovascular approaches for treating acute mesenteric arterial occlusive disease in hemodialysis patients

BACKGROUND

Among hemodialysis patients, acute superior mesenteric artery (SMA) thrombosis a condition with a high mortality rate. Very few larger case series have been reported.

METHOD

We reviewed eight hemodialysis patients with diabetes mellitus and SMA thrombosis managed with endovascular therapy in our institution. Demographic, clinical, and radiological data were described. The patency of the SMA was assessed by computed tomography angiography (CTA) at one month after the endovascular procedure. At the last visit, clinical symptoms and check of mortality were recorded.

RESULTS

Multidetector CTA scan revealed severe stenosis of SMA in 6 patients and SMA occlusion in the other two patients. The severe stenosis of SMA were verified by angiography. Balloon angioplasty without stenting was performed to obtain satisfactory patency of SMA. Seven of eight patients achieved resolution of abdominal pain after the endovascular procedure. One patient died of suspected intestinal necrosis after 6 days of balloon angioplasty. All seven surviving patients did not experience a recurrence of symptoms with a median follow-up of 2 years. No significant residual stenotic or occlusive lesions were noted in follow-up CTA at one month after the endovascular procedure.

CONCLUSION

SMA thrombosis should be systematically suspected in hemodialysis patients experiencing abdominal pain. Prompt diagnosis of SMA thrombosis as soon as possible and early endovascular therapy are required to obtain a favorable prognosis in the hemodialysis patient with SMA thrombosis.

Identifying survival protective factors for chronic dialysis patients with surgically confirmed acute mesenteric ischemia

BACKGROUND

Mesenteric ischemia is significantly more common in end-stage kidney disease patients undergoing chronic dialysis than in the general population and is associated with high morbidity and mortality. However, reports on prognostic factors in this population are limited.

AIM

To elucidate the in-hospital outcomes of acute mesenteric ischemia in chronic dialysis patients and to analyze protective factors for survival.

METHODS

The case data of 426 chronic dialysis patients who were hospitalized in a tertiary medical center for acute mesenteric ischemia over a 14-year period were retrospectively reviewed. Of these cases, 103 were surgically confirmed, and the patients were enrolled in this study. A Cox regression analysis was used to evaluate the protective factors for survival.

RESULTS

The in-hospital mortality rate among the 103 enrolled patients was 46.6%. Univariate analysis was performed to compare factors in survivors and nonsurvivors, with better in-hospital outcomes associated with a surgery delay (defined as the time from onset of signs and symptoms to operation) < 4.5 d, no shock, a higher potassium level on day 1 of hospitalization, no resection of the colon, and a total bowel resection length < 110 cm. After 1 wk of hospitalization, patients with lower white blood cell count and neutrophil counts, higher lymphocyte counts, and lower C-reactive protein levels had better in-hospital outcomes. Following multivariate adjustment, a higher potassium level on day 1 of hospitalization (HR 1.71, 95%CI 1.19 to 2.46; P = 0.004), a lower neutrophil count (HR 0.91, 95%CI 0.84 to 0.99; P = 0.037) at 1 wk after admission, resection not involving the colon (HR 2.70, 95%CI 1.05 to 7.14; P = 0.039), and a total bowel resection length < 110 cm (HR 4.55, 95%CI 1.43 to 14.29; P = 0.010) were significantly associated with survival.

CONCLUSION

A surgery delay < 4.5 d, no shock, no resection of the colon, and a total bowel resection length < 110 cm predicted better outcomes in chronic dialysis patients with acute mesenteric ischemia.

Monitoring the Sequential Organ Failure Assessment score in nonocclusive mesenteric ischemia increases the survival rate: A single-center observational study

Several large-scale studies have assessed the endovascular and surgical treatments for nonocclusive mesenteric ischemia (NOMI); nonetheless, the prognostic factors for NOMI remain unclear.In this single-center study, we retrospectively reviewed the electronic medical records of 197, 149 patients were retrieved from the inpatient database of our hospital from January 2011 to January 2020; 79 patients with NOMI were observed. A total of 44 patients who underwent laparotomy were statistically analyzed and divided into the survivor and non-survivor groups. Prognostic factors were compared between the 2 groups. Exploratory laparotomy based on a second-look surgery was the first treatment choice.The overall mortality rate was 61.3%, with a male-to-female ratio of 1.6:1. The median Sequential Organ Failure Assessment (SOFA) score was 11.06 [5.75-17.25]. The median SOFA score was 5 [interquartile range: 3-8] in the survivor group and 14.8 [interquartile range: 10.5-19] in the non-survivor group. The log-rank test showed a significant difference in the presence of diabetes mellitus (P = .025), hypoglycemia (P = .001), SOFA score ≥10 (P < .001), hemoglobin levels ≥11 g/dL (P = .003), platelet count ≥12.9 × 104/μL (P = .01), lactate levels ≥2.6 mmol/L (P = .005), and base excess <-3.0 (P < .023). Multivariate analysis using the factors with significant differences revealed that SOFA score ≥10 (hazard ratio for death, 1.199; 95% confidence interval, 1.101-1.305; P < .001) was an independent prognostic factor.The SOFA score can be used to assess disease severity. A SOFA score of ≥10 may be associated with increased mortality.

The Relationship between Intradialytic Hypotension and Hospitalized Mesenteric Ischemia: A Case-Control Study

BACKGROUND AND OBJECTIVES

Mesenteric ischemia is a rare but devastating condition caused by insufficient blood supply to meet the demands of intestinal metabolism. In patients with ESKD, it can be difficult to diagnose and has a >70% mortality rate. Patients on hemodialysis have a high prevalence of predisposing conditions for mesenteric ischemia, but the contribution of intradialytic hypotension, a potential modifiable risk factor, has not been well described.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used data from the US Renal Data System to identify 626 patients on hemodialysis with a hospitalized mesenteric ischemia event (cases). We selected 2428 controls in up to a 1:4 ratio matched by age, sex, black race, incident dialysis year, diabetes mellitus, coronary artery disease, and peripheral artery disease. We used six different definitions of intradialytic hypotension on the basis of prior studies, and categorized patients as having had intradialytic hypotension if ≥30% of hemodialysis sessions in the 30 days before the event met the specified definition.

RESULTS

The proportion of patients with intradialytic hypotension varied depending on its definition: from 19% to 92% of cases and 11% to 94% of controls. Cases had a higher adjusted odds (1.82; 95% confidence interval, 1.47 to 2.26) of having had intradialytic hypotension in the preceding 30 days than controls when using nadir-based intradialytic hypotension definitions such as nadir systolic BP <90 mm Hg. To examine a potential dose-response association of intradialytic hypotension with hospitalized mesenteric ischemia, we categorized patients by the proportion of hemodialysis sessions having intradialytic hypotension, defined using the Nadir90 definition (0%, 1%-9%, 10%-29%, 30%-49%, and ≥50%), and found a direct association of proportion of intradialytic hypotension with hospitalized mesenteric ischemia (P-trend<0.001).

CONCLUSIONS

Patients with hospitalized mesenteric ischemia had significantly higher odds of having had intradialytic hypotension in the preceding 30 days than controls, as defined by nadir-based definitions.

Colorectal Surgery Outcomes in Chronic Dialysis Patients: An American College of Surgeons National Surgical Quality Improvement Program Study

BACKGROUND

More than 450,000 US patients with end-stage renal disease currently dialyze. The risk of morbidity and mortality for these patients after colorectal surgery has been incompletely described.

OBJECTIVE

We analyzed the 30-day morbidity and mortality rates of chronic dialysis patients who underwent colorectal surgery.

DESIGN

This was a retrospective analysis.

SETTINGS

Hospitals that participate in the American College of Surgeons National Surgical Quality Improvement Program were included.

PATIENTS

The study included adult patients who underwent emergency or elective colon or rectal resection between 2009 and 2014.

MAIN OUTCOME MEASURES

Baseline characteristics were compared by dialysis status. The impact of chronic dialysis on 30-day mortality and serious postoperative morbidity was examined using multivariate logistic regression.

RESULTS

We identified 128,757 patients who underwent colorectal surgery in the American College of Surgeons National Surgical Quality Improvement Program database. Chronic dialysis patients accounted for 1% (n = 1285) and were more likely to be older (65.4 vs 63.2 years; p < 0.0001), black (27.2% vs 8.7%; p < 0.0001), preoperatively septic (22.1% vs 7.1%; p < 0.0001), require emergency surgery (52.0% vs 14.7%; p < 0.0001), have ischemic bowel (15.7% vs 1.6%; p < 0.0001), or have perforation/peritonitis (15.5% vs 4.2%; p < 0.0001). Chronic dialysis patients were also less likely to have a laparoscopic procedure (17.3% vs 45.0%; p < 0.0001). Chronic dialysis patients had higher unadjusted mortality (22.4% vs 3.3%; p < 0.0001), serious postoperative morbidity (47.9% vs 18.8%; p < 0.0001), and median length of stay (9 vs 6 days; p < 0.0001). In emergent cases (n = 19,375), multivariate logistic regression models demonstrated a higher risk of mortality for dialysis patients (OR = 1.73 (95% CI, 1.38-2.16)) but not for serious morbidity. Models for elective surgery demonstrated a similar effect on mortality (OR = 2.47 (95% CI, 1.75-3.50)) but also demonstrated a higher risk of serious morbidity (OR = 1.28 (95% CI, 1.04-1.56)).

LIMITATIONS

The postoperative 30-day window may underestimate the true incidence of serious morbidity and mortality.

CONCLUSIONS

Chronic dialysis patients undergoing elective or emergent colorectal procedures have a higher risk-adjusted mortality.

Isolated cecal necrosis: our surgical experience and a review of the literature

OBJECTIVE

Isolated cecal necrosis is a rare cause of ischemic colitis. Ischemic colitis is further divided into two groups: occlusive mesenteric ischemia and non-occlusive mesenteric ischemia. The aim of this study was to investigate the cause of isolated cecal necrosis.

MATERIAL AND METHODS

We operated on 3 male and 3 female patients with a mean age of 60.3±18.7 (38-85) years with a preliminary diagnosis of acute appendicitis between 2007 and 2012. Four of these patients were on hemodialysis, 1 patient had an aortofemoral bypass, and 1 patient had coronary artery disease with atrial fibrillation.

RESULTS

The diagnosis was made intraoperatively in all cases. Five patients died postoperatively. One patient survived.

CONCLUSION

In the case of right lower quadrant pain, the possibility of isolated cecal necrosis should be kept in mind, especially in patients on hemodialysis, elderly patients with diabetes, and heart disease; surgical strategies should be planned accordingly, and it should be understood that a high mortality rate will be inevitable.

Clinical outcomes and prognostic factors after surgery for non-occlusive mesenteric ischemia: a multicenter study

BACKGROUND

To date, no large-scale study has been undertaken to understand the clinical features of non-occlusive mesenteric ischemia (NOMI) after surgery. We thus performed a multicenter investigation to clarify the clinical outcomes and prognostic factors of NOMI.

PATIENTS AND METHODS

Clinical databases from 22 Japanese facilities were reviewed for evaluation of patients who received surgery for NOMI between 2004 and 2012. NOMI patients (n = 51) were divided into two groups: group I (n = 28) consisted of patients who survived, and group II (n = 23) consisted of patients who did not survived. Prognostic factors were compared between the two groups.

RESULTS

NOMI surgery represented 0.04% of the total number of operations performed in this time period. The overall mortality rate for NOMI surgery was 45%. Hemodialysis was a significant negative prognostic factor (p = 0.027). Preoperative elevation of transaminases, potassium, and white blood cell count, as well as metabolic acidosis and colon ischemia was poor prognostic factors. The mean Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM) score of group I versus group II was 54.5 ± 3.6 and 85.2 ± 4.1, respectively (p < 0.001).

CONCLUSIONS

Currently, NOMI surgery has a 45% mortality rate. POSSUM scores can be used to predict the clinical outcome of patients who receive NOMI surgery.

Safety analysis of intermittent hemodialysis in patients with continuous flow left ventricular assist devices

Dialysis centers adopt a cautious approach when it comes to performing intermittent hemodialysis (HD) on patients with continuous flow (CF) left ventricular assist devices (LVADs) because of the potential for volume flux-related complications and absence of pulsatile blood pressure for monitoring. Many patients have to remain hospitalized because of the inability of the dialysis centers to accept them for outpatient dialysis. In this study, the effect of HD was observed in such patients. Between June 2009 and October 2012, 139 patients received LVADs, of which 10 patients (7%) required intermittent HD postoperatively. The mean age of the patients was 53 ± 14 years and 90% were men. A total of 281 dialysis sessions were administered amounting to 1025 hours of dialysis. The mean systolic blood pressure monitored with Doppler device was 97 ± 18 mmHg. Dialysis durations averaged 218 ± 18 minutes. Mean blood flow rate was 334 ± 38 cc/min, and 2.6 ± 1.1 L was ultrafiltrated during each session. Only 15 (5.3%) sessions were interrupted or terminated in six patients. The reasons for termination were symptomatic hypotension--6 (2.1%), asymptomatic hypotension--3 (1%), ventricular tachycardia--1 (0.36%), dialysis machine malfunction--2 (0.7%), low phosphorus--2 (0.7%), and abdominal cramps--1 (0.36%). Volume expansion was necessary on three occasions. Low-flow device alarms were registered during two (0.71%) sessions. The results showed no serious adverse effects or deaths.

Outcomes of emergency surgery for acute abdomen in dialysis patients: experience of a single community hospital

PURPOSE

Long-term dialysis often causes physiological and metabolic problems that may affect the outcomes of surgery. The aim of this study was to elucidate whether emergency surgery for acute abdomen yields similar outcomes in dialysis patients versus non-dialysis patients.

METHODS

The subjects were 126 patients who underwent emergency surgery for acute abdomen between January, 2007 and November, 2011 in our hospital. They were divided into a dialysis group (HD group; n = 9) and a non-dialysis group (non-HD group; n = 117) and their postoperative morbidity and mortality were compared.

RESULTS

Postoperative morbidity and mortality were significantly worse in the HD group. All 9 of these patients succumbed to postoperative complications versus only 5 of the 117 patients in the non-HD group.

CONCLUSION

The outcomes of emergency surgery for acute abdomen were significantly worse for dialysis patients than for non-dialysis patients. Prompt diagnosis, initiation of the most suitable surgical procedure, and meticulous postoperative cares are imperative to improving the surgical outcomes of dialysis patients.

Detection of patients at high risk for non-occlusive mesenteric ischemia in hemodialysis

BACKGROUND

Nonocclusive mesenteric ischemia (NOMI) is an emerging condition in hemodialysis (HD) patients not widely studied.

MATERIALS AND METHODS

A retrospective study was conducted between 2003 and 2011. NOMI cases were recorded, and demographic, clinical, biochemical, and HD parameters were collected. This group was compared with a control group (n = 93). Risk factors, prognosis, and survival were analyzed.

RESULTS

There were 57 episodes of NOMI (incidence, 2.29 episodes per 100 patients/y). Cecum was the most frequently affected segment. Nineteen patients (33%) underwent surgery. Twenty-six patients (59%) did not survive the acute episode. Cecal damage was the only protective factor associated with mortality (relative risk [RR], 0.712; P = 0.044). The incidence of NOMI was related to erythropoietin resistance index, diabetes mellitus, and longer time on HD compared with control group (RR, 6.92, P = 0.009; RR, 9.98, P = 0.005; and RR, 1.017, P < 0.001, respectively). Mortality in survival NOMI patients was higher at 4-y follow-up compared with that in the control group (log-rank, 15.5; P < 0.0001).

CONCLUSIONS

NOMI is associated with erythropoietin resistance index, diabetes mellitus, and longer time on HD. Hypotension must be avoided in these high-risk patients to prevent NOMI.

Testicular angina during hemodialysis: an unusual complication of ultrafiltration

During hemodialysis, the development of hypotension or symptoms suggestive of ischemia is used as a surrogate marker for the establishment of dry weight. These symptoms manifest commonly as muscle cramps, chest pain or abdominal pain. Hemodialysis patients are also prone to vascular calcification which may be medial or intimal. We report the case of a 68-year-old male who developed testicular pain while attempting to establish dry weight. Computerized tomography scan of his abdomen showed extensive vascular calcification. The end result in this case was bilateral orchiectomy. Histopathology revealed hyperplastic arteriolosclerosis with intimal calcification contributing to ischemia.

Morbidity and mortality following colorectal surgery in patients with end-stage renal failure: a population-based study

PURPOSE

The risk of abdominal surgery in patients with end-stage renal failure is poorly defined. Our objective was to describe outcomes of colorectal surgery in dialysis patients from a population-based perspective.

METHODS

We analyzed the 1993 to 2007 Nationwide Inpatient Sample to identify patients hospitalized for colorectal surgery. The effect of renal failure on mortality, complications, length of stay, and charges was evaluated using logistic regression models.

RESULTS

Between 1993 and 2007, there were 755,343 admissions for colorectal surgery in the Nationwide Inpatient Sample database; 5806 patients (0.77%) were receiving dialysis treatment (87.4% hemodialysis, 4.9% peritoneal dialysis, 7.7% method not specified). Patients undergoing dialysis had an increased risk of mortality (22.1% vs 2.8%; adjusted OR 4.83; 95% CI 4.58-5.31) and complications (52.1% vs 34.0%; adjusted OR 2.04; 95% CI 1.90-2.17). Dialysis patients undergoing nonelective procedures had a 2-fold higher mortality rate than patients having had elective surgery (25.5% vs 10.3%; adjusted OR 2.01; 95% CI 1.65-2.43). In nonelective surgery, independent predictors of mortality included procedures with an end-stoma (adjusted OR 1.86; 95% CI 1.58-2.18), age over 60 (adjusted OR 1.73; 95% CI 1.43-2.08), total colectomy (adjusted OR 1.68; 95% CI 1.27-2.22), vascular insufficiency as surgical indication (adjusted OR 1.58; 95% CI 1.32-1.90), nonprivate insurance coverage (adjusted OR 1.38; 95% CI 1.07-1.77) and malnutrition (adjusted OR 1.26; 95% CI 1.01-1.59).

CONCLUSIONS

Patients receiving dialysis treatment have an increased risk of morbidity and mortality following colorectal surgery. Elective procedures are associated with a 10% rate of mortality in this population. Dialysis patients are especially susceptible to infectious and pulmonary complications after colorectal resection. Additional studies are necessary to refine risk stratification in this high-risk patient population.

Gastrointestinal disorders and renal failure: exploring the connection

Gastrointestinal complications are known to commonly occur in patients with renal failure. Uremia and dialysis have long been speculated to increase the risk of lesions in the gastrointestinal tract and accessory organs. In addition, gastrointestinal procedures such as gastrointestinal bypass surgery and the administration of colonoscopy preparations can lead to the development of renal complications. Results from studies that have attempted to define the association between renal dysfunction and gastrointestinal complications are, however, conflicting and limited by small and varied sample populations. No clear management guidelines currently exist for many of the gastrointestinal problems that accompany renal failure. This Review examines the existing data on gastrointestinal complications in patients with chronic kidney disease and end-stage renal disease and aims to outline the etiology and management of common gastrointestinal disorders in such patients.

Analysis of the Correlation of Plasma NO and ET-1 Levels in Rats With Acute Mesenteric Ischemia

Mesenteric ischemia is a devastating disease process that frequently challenges clinicians. To enhance the early diagnosis of gut ischemia and judgment of its severity, it may be helpful to detect the unusual existence or increase in biomarkers in the body fluid. The aim of the present study was to evaluate the correlation of plasma nitric oxide (NO) and endothelin-1 (ET-1) levels to mesenteric ischemia using an animal model. Acute mesenteric ischemia (AMI) was produced experimentally by occlusion of the mesenteric vessels in the terminal ileum by the tenting of a thread. The determination of plasma NO and ET-1 levels were obtained before operation (T0, baseline value), and at 10 (T10), 20 (T20), 30 (T30), and 60 (T60) min after the creation of AMI. Sham-operated rats served as controls. After 30 min of experiments, the plasma NO and ET-1 levels were significantly higher in the AMI group than in the control group (both p < .01). Both the plasma NO and ET-1 levels in AMI group increased significantly after 30 min of ischemia (both p < .001 vs. respective baseline value), and they were 60% and 84% above the baseline value, respectively. In addition, ischemic intestinal injury was confirmed by the significantly elevated histological scores in the AMI group after 60 min of ischemia (p < .001). Our preliminary results suggest the possibility of important insights regarding NO and ET-1 changes into the mechanism of pathogenesis in AMI in rats. The increases in plasma NO and ET-1 levels may potentially be noninvasive biomarkers for the early detection of this disease.

Acute non-occlusive mesenteric ischemia of the small bowel in a patient started on hemodialysis: a case report

BACKGROUND

Non-occlusive mesenteric ischemia is not uncommon in chronic hemodialysis patients and is the major cause of an acute abdomen in this population. Intensive ultrafiltration and intradialytic hypotension are usually the precipitation factors. A definite diagnosis is usually late and associated with high mortality. We present a rare case of a patient who developed abdominal symptoms during his first week on HD without having obvious hypotensive episodes.

CASE PRESENTATION

A 76-year-old man was admitted with pulmonary edema and renal failure developed abdominal symptoms during his first week on hemodialysis without having obvious hypotensive episodes. Abdominal diagnostic procedures were all unrevealing. Mesenteric ischemia was diagnosed during laparoscopy done on the basis of physical findings and clinical suspicion. Ischemic small bowel of the distal ileum was resected and histopathology examination of the small bowel demonstrated transmural ischemic necrosis with hemorrhages and non-occluded mesenteric artery. Patient maid a steady recovery, and was discharged on the 11th post-operative day.

CONCLUSION

Mesenteric ischemia should be systematically suspected in dialysis patients experiencing even mild and nonspecific abdominal symptoms with or without hemodialysis-induced hypotensive episodes. Identification of patients at risk and prevention of intradialytic hypotension may help to reduce the incidence of this potentially fatal complication in hemodialysis patients.

Outcome of patients on renal replacement therapy after colorectal surgery

PURPOSE

Patients on renal replacement therapy are reported to have a high complication rate after abdominal surgery, the result of uremia and immunosuppression. A review of this group of patients undergoing colorectal surgery was undertaken.

METHODS

Seventy-three separate colorectal operations were performed for 44 patients. Thirty-eight patients were on dialysis and 35 had a renal transplant. Data (coexisting disease, preoperative blood results, operative details, complications, and colorectal POSSUM score) were completed for each surgical event.

RESULTS

Forty-two elective and 31 emergency procedures were performed. Infective complications were common (overall 60 percent). There were two anastomotic leaks in the elective group, but five leaks from seven emergency anastomoses. Stomas were frequently raised. Ninety percent of patients who survived and had a defunctioning stoma underwent a successful reversal. The overall major complication rate after elective and emergency surgery was 19 and 81 percent, respectively, and mortality was 5 and 26 percent, respectively.

CONCLUSIONS

Renal patients have a high rate of complications after colorectal surgery, and emergency surgery has a significant risk of anastomotic leak. Primary anastomosis should be avoided in all patients undergoing emergency intestinal resections. Subsequent surgery to restore intestinal continuity is possible in 90 percent of patients with far fewer complications.

Survival of three nonocclusive mesenteric ischemia patients following early diagnosis by multidetector row computed tomography and prostaglandin E1 treatment

Nonocclusive mesenteric ischemia (NOMI) is an acute mesenteric circulatory disorder which is characterized by spasm and narrowing of the arterial branches. In contrast to occlusive disease, early diagnosis of NOMI is difficult because of its mild symptoms, thus resulting in a high mortality rate. In this study, we report three cases who survived NOMI because of early diagnosis by multidetector row computed tomography and immediate treatment with prostaglandin E1, which is known to improve blood flow by relaxing vascular smooth muscle. We conclude that early diagnosis and treatment of NOMI with prostaglandin E1 considerably improves the prognosis of this disease.

Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings--compared with pathologic diagnoses-- predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.

Non-occlusive mesenteric ischemia in chronically dialyzed patients: a disease with multiple risk factors

BACKGROUND

Non-occlusive mesenteric ischemia (NOMI) can be a fatal complication in dialysis patients. Intradialytic hypotension is usually the precipitating factor. The occurrence of 16 cases in 5 years (1998-2002), compared with only 4 in previous years, led us to investigate other risk factors contributing to NOMI. A control group of stable hemodialysis patients was used for comparison.

RESULTS

20 patients were studied: 17 diagnosed surgically, and 3 clinically. The mean age was 70.8 +/- 1.8 years, and the male:female ratio 7:13. Nineteen patients were on hemodialysis. Clinically overt atherosclerosis was present in 17 patients. Preceding dialysis-associated hypotension was identified in all patients studied and access thrombosis in 6 patients. In all patients, abdominal pain was the presenting symptom. Initial abdominal examination was unimpressive in 16 patients. The hemoconcentration, leukocytosis and metabolic acidosis were the most prominent laboratory findings. 5/11 abdominal sonograms showed intestinal pathology. 2/3 angiographies were diagnostic. Three patients responded to early fluid challenge and did not require surgery. Pathology was related to the area of the superior mesenteric artery in all 15 patients operated. Twelve (60%) patients died from the event. The 1-year mortality rate was 17/20 patients (85%). Possible contributing factors, other than dialysis-associated hypotension, included: high-dose recombinant human erythropoietin (rhEPO) therapy (179 +/- 35 vs. 116 +/- 10 U/kg/week in the control group, p < 0.05); metastatic calcifications (abdominal aorta 14/14, aortic valve 11/18; medial calcification of mesenteric arteries in 2/11 pathology specimens); digoxin, and hypoalbuminemia.

CONCLUSIONS

The increased incidence of NOMI in dialysis patients may be related to overly aggressive rhEPO therapy and the unsuspected presence of mesenteric arterial medial calcifications. Identification of patients at risk, prevention of intradialytic hypotension and a controlled increase in dry weight may help to reduce the incidence of NOMI in chronically dialyzed patients.

Mesenteric ischaemia in haemodialysis patients: a case/control study

BACKGROUND

Mesenteric ischaemia is not uncommon in dialysis patients and seems to have been increasing in the last decade. However, the risk factors for mesenteric ischaemia are unclear and prognosis of patients after this type of ischaemic accident is not well defined.

METHODS

From January 1988 to June 1999, 15 haemodialysis patients (0.3% per patient-year) from a single institution presented with mesenteric ischaemia and the clinical, biological and radiological aspects of the ischaemia were described. To identify risk factors for mesenteric ischaemia, each ischaemic patient (case) was matched with two other haemodialysis patients not having ischaemia (controls). Survival curves were then established for the two groups.

RESULTS

A marked hypotensive episode was present in seven out of 15 case patients (47%) during dialysis sessions that preceded mesenteric ischaemia. Abdominal pain, guarding, fever and hyperleucocytosis were all present in 13 out of 15 patients (87%). An abdominal computerized tomography scan with opaque enema enabled a rapid diagnosis for six patients. The caecum was the most frequently (47%) affected segment. Twelve patients were surgically treated and the remaining three were given medical support. The two groups (case and control) were not different in cardiovascular risk factors, comorbidity, administered drugs or main haemodialysis characteristics. The median survival of the case group was 600 days, whereas 80% of the control group survived beyond this period (P=0.0132). Eleven case patients survived >3 months after mesenteric ischaemia and had a median survival of 1500 days, which was identical to their matched control patients.

CONCLUSIONS

Mesenteric ischaemia should be systematically suspected in patients experiencing abdominal pain during or after dialysis sessions. Prompt diagnosis and treatment usually allow for a favourable prognosis.

Nonocclusive mesenteric ischemia in a patient on maintenance hemodialysis

Nonocclusive mesenteric ischemia (NOMI) is known to occupy about 25% to 60% of intestinal infarction. NOMI has been reported to be responsible for 9% of the deaths in the dialysis population and the postulated causes of NOMI include intradialytic hypotension, atherosclerosis and medications, such as diuretics, digitalis and vasopressors. Clinical manifestations, such as fever, diarrhea and leukocytosis, are nonspecific, which makes early diagnosis of NOMI very difficult.

CASE

A 66-year-old woman on maintenance hemodialysis for 5 years was admitted with syncope, abdominal pain and chilly sensation. Since 7 days prior to admission, blood pressure on the supine position during hemodialysis had frequently fallen to 80/50 mmHg. Four days later, she complained of progressive abdominal pain. Rebound tenderness and leukocytosis (WBC 13900/mm3) with left shift were noted. Stool examination was positive for occult blood. Abdominal CT scan showed a distended gall bladder with sludge. Under the impression of acalculous cholecystitis, she was operated on. Surgical and pathologic findings of colon colon were compatible with NOMI. Because of recurrent intradialytic hypotension, we started midodrine 2.5 mg just before hemodialysis and increased the dose up to 7.5 mg. After midodrine therapy, blood pressure during dialysis became stable and the symptoms associated with hypotension did not recur.

CONCLUSION

As NOMI may occur within several hours or days after an intradialytic hypotensive episode, abdominal pain should be carefully observed and NOMI should be considered as a differential diagnosis. In addition, we suggest that midodrine be considered to prevent intradialytic hypotensive episodes.

Nonocclusive mesenteric infarction in hemodialysis patients

BACKGROUND

Dialysis patients develop nonocclusive mesenteric ischemia (NOMI) at an increased rate. Previous studies have associated atherosclerosis and hemodialysis-induced hypotension as inciting factors for NOMI development. A retrospective review of 29 of 1,370 longterm hemodialysis patients who developed NOMI from January 1992 to December 1997 was performed. The NOMI patients were compared with a similar profile of hemodialysis patients to identify risk factors for the development of NOMI and for outcomes assessment.

STUDY DESIGN

All NOMI patients had hypotensive episodes during hemodialysis the week before the development of abdominal symptoms, and additional risk factors of hypertension (83%), diabetes (55%), and atherosclerosis (38%). The majority of patients (83%) experienced abdominal pain more than 24 hours before admission. Sixty-six percent of patients had leukocytosis on admission laboratory data.

RESULTS

Sixteen patients (55%) had ischemia of the small bowel, all underwent laparotomy, and nine (56%) died. Thirteen patients (45%) had ischemia of the colon and were managed nonoperatively; four (31%) of them died. Overall mortality rate for NOMI was 45%.

CONCLUSIONS

NOMI occurs at an increased rate in hemodialysis patients. Identification of patients at high risk for NOMI and dose monitoring of filtration rates may impact on the high mortality of this disease.

Abdominal Surgery in Chronic Hemodialysis Patients

The number of patients with end-stage renal disease who benefit from chronic dialysis is steadily increasing. This study was designed to assess abdominal surgery in chronic hemodialysis (CHD) patients. A 7-year retrospective study was conducted including all the patients on CHD who underwent abdominal surgery in our unit. These patients were separated into an elective and an emergency surgery group. Forty-three patients underwent surgery. In the elective surgery group (18 patients), the most common diseases were colorectal cancer, symptomatic gallbladder stones, and hernia. There was no death related to surgery in this group, and only one patient developed a complication (5%). In the emergency surgery group (25 patients), the most common diseases were mesenteric ischemia and gastrointestinal bleeding from angiodysplasia. Complications occurred in 10 patients (total morbidity rate, 40%), and 6 of them died (mortality rate, 24%). Gastrointestinal elective surgery in patients on CHD can be performed with low morbidity and mortality rates. The emergency group was differentiated by the high prevalence of bleeding from angiodysplasia and mesenteric infarction, as well as its high surgical mortality rate.

Survival among chronic renal failure patients requiring major abdominal surgery

BACKGROUND

There is limited literature on survival of patients with chronic renal failure (CRF) who require major abdominal surgery. The goal of the present study was to evaluate indications for surgery and survival among dialysis patients undergoing major abdominal operations.

STUDY DESIGN

Medical records for 26 CRF patients at our institution undergoing major nonvascular abdominal operations from 1990 to 1996 were reviewed. Results were evaluated by chi-square analysis.

RESULTS

Surgery was performed emergently in 21 patients (81%) and electively in 5 patients (19%). The most common finding among the emergency surgery patients was ischemic colitis, occurring in 9 of 21 patients (43%). Postoperative (30-day) mortality among the emergency surgery patients was 38%. Longterm (1 year) survival was 28%. All 5 patients undergoing elective surgery are alive on followup of 1 to 5 years. The disparity in longterm survival between the emergency surgery versus the elective surgery patients was statistically significant (p = 0.004).

CONCLUSIONS

Emergency surgery in patients with CRF is associated with poor survival rates. Colonic ischemia is a significant problem among these patients.

Abdominal surgery for patients on maintenance hemodialysis

Despite the growing number of major surgical procedures being performed for patients on maintenance hemodialysis, few reports focus on the management and outcome of such patients, especially those undergoing major abdominal surgery. We conducted a retrospective review of 30 patients on maintenance hemodialysis who underwent abdominal surgery, 20 of whom underwent an elective operation and 10, an emergency operation. The indications of elective surgery included gastrointestinal cancer, biliary tract disease, and abdominal aortic aneurysm, while those for emergency surgery mainly involved gastrointestinal perforation or bleeding. There were no statistically significant differences between the elective group and the emergency group regarding either the mean time on hemodialysis or the preoperative clinical data. The morbidity and mortality rates were 15% and 10%, respectively, for the patients who underwent elective surgery and 50% and 70%, respectively, for those who underwent emergency surgery (P < 0.01 and P < 0.05, respectively). Those patients with more than a 2-year history of hemodialysis had a significantly higher mortality rate following abdominal surgery than those with less than a 2-year history (P < 0.01). Thus, the morbidity and mortality rates of patients on maintenance hemodialysis who require major abdominal surgery are significantly high, which reinforces the need to further improve the intensive perioperative management of such patients.

The influence of ischemic bowel wall damage on translocation, inflammatory response, and clinical course

BACKGROUND

While vascular patency and overall viability of the gut can be evaluated perioperatively, damage to the mucosal barrier can hardly be judged in the perioperative setting and, moreover, will probably determine the clinical course.

METHODS

In 19 consecutive cases with intestinal ischemia, the clinical course was correlated to the severity of the disease (APACHE II; Septic Severity Score, SSS), the intraabdominal and systemic inflammatory response, and the translocation of bacteria and endotoxin.

RESULTS

The comparison of the 10 survivors with the nonsurviving group revealed no differences as to the length of history, serum lactate levels, white blood cell counts, body temperature, markers of the inflammatory response, or quantity and macroscopic quality of the exudate. Differences were found in intraperitoneal bacteriology (prevalence 0.37, negative predictive value for lethal outcome 0.8), endotoxin concentrations in the exudate (P = 0.02) and in the plasma (P = 0.015), fibrinopeptide A levels (exudate P = 0.036; plasma P = 0.015), PGE2 plasma concentration (P = 0.0357), and APACHE II (P = 0.0034) and SSS (P = 0.0027) values.

CONCLUSION

The clinical course of ischemic bowel wall necrosis seems to depend on the severity of the disease at admission and on the integrity of the mucosal barrier rather than on inflammatory response, therapeutic measures, or supportive treatment.