Nonocclusive mesenteric ischemia in a patient on maintenance hemodialysis

Discontinuity of marginal artery at splenic flexure and rectosigmoid junction: A systematic review and meta-analysis

AIM

The aim of this study was to provide comprehensive evidence-based assessment of the discontinuity of the marginal artery at the splenic flexure (SF) and the rectosigmoid junction (RSJ).

METHOD

A systematic review was conducted of literature published to 26 December 2022 in the electronic databases PubMed, SCOPUS and Web of Science to identify studies eligible for inclusion. Data were extracted and pooled into a meta-analysis using the Metafor package in R. The primary outcomes were the pooled PPEs of the marginal artery at the SF and the RSJ. The secondary outcome was the size of vascular anastomoses.

RESULTS

A total of 21 studies (n = 2,864 patients) were included. The marginal artery was present at the splenic flexure in 82% (95% CI: 62-95) of patients. Approximately 81% (95% CI: 63-94%) of patients had a large macroscopic anastomosis, while the remainder (19%) had small bridging ramifications forming the vessel. The marginal artery was present at the RSJ in 82% (95% CI: 70-91%) of patients.

CONCLUSION

The marginal artery may be absent at the SF and the RSJ in up to 18% of individuals, which may confer a higher risk of ischaemic colitis. As a result of high interstudy heterogeneity noted in our analysis, further well-powered studies to clarify the prevalence of the marginal artery at the SF and the RSJ, as well as its relationship with other complementary colonic collaterals (intermediate and central mesenteric), are warranted.

Mild nonocclusive mesenteric ischemia associated with syncope

Nonocclusive mesenteric ischemia (NOMI) is a life-threatening disease caused by a reduction in mesenteric blood supply without vascular occlusion. Early diagnosis of NOMI is often difficult because there are no specific findings suggesting NOMI. Here, we report a rare case of a very elderly patient with mild NOMI caused by dehydration due to short-term reduced oral intake and associated with syncope. A 90-year-old man was admitted to our hospital with syncope and melena. The syncope was thought to be caused by orthostatic hypotension due to dehydration owing to reduced oral intake for approximately 24 h. Abdominal computed tomography (CT) revealed marked bowel wall thickening with mesenteric stranding in the ileum and ascending colon, dilated small intestine with thinned bowel wall, collapsed superior mesenteric vein, hemorrhagic ascites, and absence of obvious vascular occlusion in the mesenteric vessels. Abdominal symptoms, laboratory abnormalities, and CT findings improved gradually with the correction of dehydration. Therefore, we diagnosed our patient with mild NOMI. NOMI can be associated with syncope and can occur even with dehydration due to short-term reduced oral intake. When examining elderly patients with hypovolemic signs, such as syncope, who exhibit abdominal symptoms, clinicians must keep in mind the possibility of NOMI.

Hepato-splanchnic circulatory stress: An important effect of hemodialysis

The gastro-intestinal tract is being increasingly recognized as the site of key pathophysiological processes in the hemodialysis patient. Intestinal dysbiosis, increased intraluminal toxin production, and increased intestinal permeability are commonly observed processes which contribute to the pathogenesis of cardiovascular disease and thus elevated mortality. The acute circulatory effects of dialysis itself may contribute significantly to the development of gastrointestinal dysfunction as a result of both local and distant effects. Additionally, the liver, a relatively unknown entity in this process, has a substantial role as a functional barrier between the portal and systemic circulation and in the metabolism of pathogenic gut-derived uremic toxins. Here we summarize the evidence for acute gastro-intestinal and hepatic effects of hemodialysis and identify gaps in knowledge to date which require further study.

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.

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.

Non-occlusive mesenteric ischemia (NOMI): utility of measuring the diameters of the superior mesenteric artery and superior mesenteric vein at multidetector CT

OBJECTIVE

To investigate the diagnostic capability of multidetector computed tomography for detecting non-occlusive mesenteric ischemia (NOMI).

METHODS

We studied 11 NOMI patients and 44 controls. Radiologists evaluated the CT images for the presence of bowel ischemia and measured the diameters of the superior mesenteric artery and the superior mesenteric vein (D SMA and D SMV). We also performed linear discriminant analysis (LDA) using D SMA and D SMV.

RESULTS

All NOMI patients presented with more than 2 CT findings of bowel ischemia. D SMA and D SMV were significantly smaller in NOMI patients than in the controls (p < 0.01). At the optimal cut-off values for D SMA (6.5 mm), D SMV (9.0 mm), and the Z value in LDA (0.93), sensitivity and specificity were 81.8 and 81.8; 81.8 and 88.6; and 81.8 and 97.7 %, respectively.

CONCLUSIONS

D SMA and D SMV were significantly smaller in NOMI patients than in the controls and D SMV is a more significant parameter than D SMA.

Survival in nonocclusive mesenteric ischemia: early diagnosis by multidetector row computed tomography and early treatment with continuous intravenous high-dose prostaglandin E(1)

OBJECTIVES

The aim of the study was to establish a procedure for early diagnosis and treatment of nonocclusive mesenteric ischemia (NOMI).

BACKGROUND

NOMI has a high mortality rate, and early diagnosis and treatment are important for improving survival in patients with this condition.

METHODS

The subjects were 22 patients treated at our hospital over 13 years. Diagnostic criteria for NOMI were established based on the first 13 cases. In the 9 more recent cases, we performed abdominal contrast multidetector row computed tomography (MDCT) upon suspicion of NOMI based on these criteria. Imaging allowed definite diagnosis of NOMI, and continuous intravenous high-dose PGE1 administration was initiated immediately after diagnosis (dose, 0.01-0.03 microg/kg per min; mean administration period, 4.8 days).

RESULTS

Nine of the first 13 patients died of multiple organ failure associated with multiple intestinal necrosis. These cases suggested that NOMI may develop when 3 of the following 4 criteria are met after cardiovascular surgery or maintenance dialysis in elderly patients: symptoms of the ileus develop slowly from abdominal symptoms, such as an unpleasant abdominal feeling or pain; a requirement for catecholamine treatment; an episode of hypotension; and slow elevation of the serum transaminase level. In the 9 recent cases, definite diagnosis was made from spasm of the principal arteries in arterial volume rendering and curved planar reformation MDCT images. Early treatment with PGE1 prevented acute-stage NOMI in 8 of the 9 cases.

CONCLUSIONS

Early diagnosis of NOMI is possible using the above criteria and MDCT, and initiation of PGE1 treatment may increase survival in patients with NOMI.

Comparison of effects of vitamin E and wen-jing-tang (unkei-to), an herbal medicine, on peripheral blood flow in post-menopausal women with chilly sensation in the lower extremities: a randomized prospective study

We examined the association between blood flow and chilly sensation in the lower extremities, comparing the changes in blood flow induced by the vitamin E and herbal therapy (Wen-jing-tang) in perimenopausal women with chilly sensation. One hundred sixty-one perimenopausal women aged 42-61 years (mean: 50.4 +/- 3.8 years) with chilly sensation in the lower extremities participated in the study. The participants were randomized for treatment with Wen-jing-tang or a vitamin E preparation containing 600 mg tocopherol nictinate per day for 8 weeks. Blood flow measurement was performed by laser Doppler fluxmetry to determine tissue under the jaw, in the middle finger, and in the third toe. Wen-jing-tang significantly increased the peripheral blood flow in the skin surface in the tiptoe (12.8 +/- 8.8, p = 0.0068) from basal levels (6.0 +/- 5.1), although no significant change was observed in the blood flow in fingertip or under the jaw during treatment. The rate of increase of blood flow in the skin surface of in the lower extremities was significantly higher in the Wen-jing-tang treating group (116.4 +/- 46.5%) than in the vitamin E group (39.8 +/- 21.3%) (p < 0.0001). When the effects of herbal treatment and vitamin E treatment were compared in the subjects with baseline upper extremity blood flow above the mean + 1.5 SD, mean blood flow through the upper extremities was found to have been significantly decreased after Wen-jing-tang treatment (from 57.7 +/- 4.8 to 43.1 +/- 4.2, p = 0.0277), whereas it remained unchanged after treatment with vitamin E. Classical monographs described Wen-jing-tang as being particularly useful in curing chilly sensation in lower extremities. The present study using a laser Doppler fluxmeter demonstrated that treatment with this herbal medicine significantly increased blood flow through the periphery of lower extremities in patients with chilly sensation. It also showed that this herbal medicine suppresses excessive blood flow through the upper half of the body and thus stimulates restoration of physiological distribution of blood flow throughout the entire body.

Intestinal ischemia

Ischemic injury to the gastrointestinal tract can threaten bowel viability with potential catastrophic consequences, including intestinal necrosis and gangrene. The presenting symptoms and signs are relatively nonspecific and diagnosis requires a high index of clinical suspicion. AMI often results from an embolus or thrombus within the SMA, although a low-flow state through an area of profound atherosclerosis may also induce severe ischemia. Because most laboratory and radiologic studies are nonspecific in early ischemia an aggressive approach to diagnosis with imaging of the splanchnic vasculature by mesenteric angiography is advocated. Various therapeutic approaches, including the infusion of vasodilators and thrombolytics, may then be used. Proper diagnosis and management of patients with AMI requires vigilance and a readiness to pursue an aggressive course of action.

Setting the stage

Intradialytic hypotension (IDH) occurs during 25% to 50% of end-stage renal disease (ESRD) hemodialysis (HD) treatments. The development of IDH signals both technology- and patient-dependent limitations expressed across a broad range of symptoms, from nausea and muscle cramps to ischemic injury. While traditional thinking has emphasized the link between hypertension and cardio-cerebrovascular injury, more recent studies of ESRD patients have stimulated significant interest in hypotension and poor outcomes. Theoretically, hypotension can contribute to the increased relative risk of death in ESRD by several mechanisms, which include acute coronary syndrome, autoregulation dysfunction, ischemia, and arrhythmogenicity. Endothelial abnormalities (increased procoagulation, thrombogenecity risk, and alterations in coronary flow reserve) and altered vascular distribution within the myocardium provide an environment for vascular injury. The current symposia will examine the pathophysiology of IDH, the specific HD prescription modifications to prevent IDH, and newer pharmacologic interventions to treat IDH and will highlight the approach to several clinical cases based on the information presented. It is becoming increasingly important to identify patients at "high risk" for IDH, to customize the HD prescription to the individual patient, to use drug therapy to prevent IDH events, and to track the prevalence of chronic hypotension and the incidence of IDH complications in the dialysis unit.

Ischemic bowel disease in the elderly

The ischemic bowel diseases are a heterogeneous group of disorders usually seen in elderly individuals. They represent ischemic damage to different portions [figure: see text] of the bowel and produce a variety of clinical syndromes and outcomes. Colonic ischemia is the commonest of these disorders and has a favorable prognosis in most cases. In contrast, acute mesenteric ischemia, most commonly caused by a superior mesenteric artery embolus, is a disease with a poor prognosis. Acute mesenteric ischemia secondary to nonocclusive mesenteric ischemia usually is a [figure: see text] catastrophic complication of other severe medical illnesses, most notably atherosclerosis. Proper diagnosis and management of patients with ischemic bowel disease requires vigilance on the part of the physician and a willingness to embark on an aggressive plan of diagnosis and management in the appropriate setting.