Neutrophil to lymphocyte ratio predicts bowel ischemia in non-strangulated adhesive small bowel occlusions: a retrospective analysis from an acute care surgical service.

BACKGROUND: Adhesive small bowel obstruction (ASBO) is a leading cause of hospitalization in emergency surgery. The occurrence of bowel ischemia significantly increases the morbidity and mortality rates associated with this condition. Current clinical, biochemical and radiological parameters have poor predictive value for bowel ischemia. This study is designed to ascertain predictive elements for the progression to bowel ischemia in patients diagnosed with non-strangulated ASBO who are initially managed through conservative therapeutic approaches. METHODS: The study was based on the previously collected medical records of 128 patients admitted to the Department of Acute Care Surgery of Padua General Hospital, from August 2020 to April 2023, with a diagnosis of non-strangulated adhesive small bowel obstruction, who were then operated for failure of conservative treatment. The presence or absence of bowel ischemia was used to distinguish the two populations. Clinical, biochemical and radiological data were used to verify whether there is a correlation with the detection of bowel ischemia. RESULTS: We found that a Neutrophil-Lymphocyte ratio (NLR) > 6.8 (OR 2.9; 95% CI 1.41-6.21), the presence of mesenteric haziness (OR 2.56; 95% CI 1.11-5.88), decreased wall enhancement (OR 4.3; 95% CI 3.34-10.9) and free abdominal fluid (OR 2.64; 95% CI 1.08-6.16) were significantly associated with bowel ischemia at univariate analysis. At the multivariate logistic regression analysis, only NLR > 6.8 (OR 5.9; 95% CI 2.2-18.6) remained independent predictive factor for small bowel ischemia in non-strangulated adhesive small bowel obstruction, with 78% sensitivity and 65% specificity. CONCLUSIONS: NLR is a straightforward and reproducible parameter to predict bowel ischemia in cases of non-strangulated adhesive small bowel obstruction. Employing NLR during reevaluation of patients with this condition, who were initially treated conservatively, can help the acute care surgeons in the early prediction of bowel ischemia onset.

Pearls and Pitfalls of Imaging Small Bowel Obstruction.

Small bowel obstruction (SBO) is a common condition encountered by radiologists in the evaluation of patients with abdominal pain, and is an important diagnosis to be comfortable with given substantial associated morbidity and mortality. In this review, we summarize an imaging approach to evaluating patients with suspected SBO, discuss the role of certain imaging modalities such as radiography and small bowel follow through, CT, and MRI, as well as review some common and also less common causes of SBO such as internal hernia. We will also discuss tailoring the imaging approach to address specific clinical questions and special patient populations such as imaging the pregnant patient with suspected SBO, and the inflammatory bowel disease patient.

Gastric ischemia as an under-reported cause of death in older people.

Acute gastric ischemia is a rare condition due to the rich vascular supply of the stomach. Here we present a case of fatal gastric ischemia associated with bowel ischemia, only diagnosed at autopsy, which was requested for the suspicion of medical liability. A complete post-mortem examination was conducted, along with a macroscopic analysis of the superior mesenteric artery and detailed histological analyses. Past clinical data was also reviewed. The macroscopic blackish discoloration of the stomach and the bowel, coupled with the presence of neutrophils in the mucosa and submucosal non-occlusive thrombi, were consistent with gastric and bowel ischemia, despite the presence of confounding putrefactive changes. The unique aspect of this case resides in the ante-mortem peculiar vascularization of the stomach, supplied by small collateral vessels. No mechanical occlusion was identified, and the cause of the ischemia was deemed as non-occlusive, likely due to systemic hypoperfusion. The analysis of clinical data and documentation of associated comorbidities are strongly recommended, especially when a rare cause of death is suspected. With the aging population, especially among women, and the prevalence of risk factors, the forensic pathologist could increasingly encounter rare cases of gastric ischemia.

Diagnostic nomogram for closed-loop small bowel obstruction requiring emergency surgery.

PURPOSE: This study aimed to build a diagnostic model of closed-loop small bowel obstruction (CL-SBO) using clinical information, blood test results, and computed tomography (CT) findings. METHODS: All patients who were diagnosed with small bowel obstruction (SBO) and underwent surgery between January 1, 2018, and October 31, 2021, in the affiliated hospital of Qingdao university were reviewed, and their relevant preoperative information was collected. All variables were selected using univariate analysis and backward stepwise regression to build a diagnostic nomogram model. K-fold cross-validation and bootstrap resampling techniques were used for internal validation, and data from Qingdao Central Hospital were used for external validation. We also evaluated the diagnostic performance of each CT finding and performed subgroup analysis according to bowel ischemia in the closed-loop small bowel obstruction (CL-SBO) group. RESULTS: A total of 219 patients (95 in the CL-SBO group and 124 in the open-loop small bowel obstruction [OL-SBO] group) were included in our research. D-dimers (median 1085 vs. 690, P = 0.019), tenderness (77.9% vs. 59.7%, P = 0.004), more than one beak sign (65.3% vs. 30.6%, P < 0.001), radial distribution (18.9% vs. 6.5%, P = 0.005), whirl sign (35.8% vs. 8.9%, P < 0.001), and ascites (71.6% vs. 53.2%, P = 0.006) were selected as the predictive variables of the nomogram. This model's Harrell's C statistic was 0.786 (95% confidence interval (CI), 0.724-0.848), and the Brier score was 0.182. The Harrell's C statistic of external validation was 0.784 (95%CI, 0.664-0.905); the Brier score was 0.190. Regarding the CT findings, radial distribution, U/C-shaped loop, and whirl sign had high specificity (93.5%, 96.0%, and 91.1%, respectively), but low sensitivity (18.9%, 8.4%, and 35.8%, respectively). D-dimer levels and tenderness were also associated with bowel ischemia. CONCLUSION: The nomogram accurately predicted CL-SBO in patients with SBO, and surgery should be considered when patients have a high risk for developing CL-SBO.

Small bowel obstruction with bowel ischemia due to ingestion of water-absorbing bead.

Foreign body aspiration accounts for 7% of accidental deaths in children under age 4 (4). Children between the ages of 6 months and 3 years of age, adolescent boys and children with mental health issues are at the highest risk of foreign body ingestion. Coins are the most commonly swallowed foreign body in the United States (US) and in other countries those related food such as fish bones are most common (10). Most cases are accidental and pass harmlessly through the gastrointestinal tract with low mortality (10). The most common complication is esophageal obstruction particularly at the thoracic inlet. However, the object can become lodged anywhere in the gastrointestinal tract. We present an unusual case of small bowel obstruction and bowel ischemia secondary to superabsorbent polymer water bead ingestion in a pediatric patient.

COVID-19 induced aorto duodenal fistula following evar in the so called "negative" patient.

OBJECTIVES: Since October 2019, SARS-CoV-2 pandemic represents a challenge for the international healthcare system and for the treatment and survival of patients. We normally focus on symptomatic patients, and symptoms can range from the respiratory to the gastrointestinal system. In addition, we consider patients without fever and respiratory symptoms, with both a negative RT nasopharyngeal swab and lung CT, as a "Covid-19 negative patient." In this article, we present a so called Covid-19 "negative" patient, with an unsuspected vascular clinical onset of the viral infection. METHODS: An 80 y.o. man, who previously underwent endovascular aortic repair for an infrarenal abdominal aortic aneurysm, presented to our department with an atypical presentation of an aorto-enteric fistula during the pandemic. While in hospital, weekly nasopharyngeal swab tests were always negative for SARS-CoV-2. However, the absence of aortic endograft complications, the gross anatomy of duodenal ischemic injury, and the recent history of the patient who lived the last months in Bergamo, the Italian city with the highest number of COVID-19 deaths, lead the senior Author to suspect an occult SARS-CoV-2 infection. The patient underwent to resection of the fourth portion of the duodenum and the first jejunal loop, with subsequent duodenum-jejunal latero-lateral anastomosis and the direct suture of the aortic wall. The intestinal specimen was investigated as suspected SARS-CoV-2 bowel infection by the means of immune-histochemistry (IHC). An ileum sample obtained in the pre-COVID-19 era was used as a control tissue. RESULTS: The histological analysis of the bowel revealed sustained wall ischemia and liponecrosis of the duodenal wall, with intramural blood vessels thrombosis. Blood vessel endotheliitis and neo-angiogenesis were also observed. Finally, the IHC was strongly positive for SARS-CoV-2 RNA and for HLA-G presence, with a particular concentration both in blood vessels and in the intestinal villi. The control tissue sample was not positive for both SARS-CoV-2 and HLA-G. CONCLUSIONS: Coronavirus pandemic continues to be an international challenge and more studies and trials must be done to learn its pathogenesis and its complications. As for thromboembolic events caused by SARS-COV-2, vascular surgeons are involved in treatment and prevention of the complications of this syndrome and must be ready with general surgeons to investigate atypical and particular cases such as the one discussed in this article.

Bowel ischemia as onset of COVID-19 in otherwise asymptomatic patients with persistently negative swab.

BACKGROUND: Asymptomatic patients with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) can develop hypercoagulable conditions and acute vascular events. The objective of this study is to determine whether SARS-CoV-2 was present in resected specimens from patients with acute bowel ischemia, but asymptomatic for Coronavirus Disease 2019 (COVID-19) and with persistently real-time polymerase chain reaction negative pharyngeal swab. METHODS: Three consecutive patients presented severe abdominal symptoms due to extensive ischemia and necrosis of the bowel, with co-existent thrombosis of abdominal blood vessels. None had the usual manifestations of COVID-19, and repeated pharyngeal swabs tested negative. They underwent emergency surgery with intestinal resection. Immunohistochemical testing for SARS-CoV-2 on resected tissue was performed. RESULTS: All tested samples were strongly positive for SARS-CoV-2. CONCLUSIONS: This is the first case report in which patients with severe intestinal symptoms presented a marked SARS-CoV-2 positivity in the resected tissues, without any usual clinical manifestations of COVID-19. These results suggest that the patients might be infected with SARS-CoV-2 presenting acute abdominal distress but without respiratory or constitutional symptoms.

Predicting outcomes of mesenteric ischemia postcardiac surgery: A systematic review.

OBJECTIVE: This systematic review aims to identify predictors of outcomes of mesenteric ischemia in patients following cardiac surgery. METHODS: A comprehensive literature search was done on EMBASE, PubMed, Ovid MEDLINE, and SCOPUS using keywords relating to bowel ischemia and cardiac surgery. Database search results were screened by at least two authors and 32 articles were selected for inclusion in this review. RESULTS: Data on 1907 patients were analyzed. The mean age was 70.0 ± 2.99 years and the prevalence of bowel ischemia was 1.74%. Advanced age was a significant risk factor. 63.16% of patients reported were men, and 58.4% of patients died in hospital. There was heterogeneity in the reported significance of the following preoperative risk factors: hypertension, smoking status, type 2 diabetes mellitus, end-stage renal disease, preoperative left ventricular ejection fraction <35%. Cardiopulmonary bypass (CPB) time, preoperative/operative intra-aortic balloon pump (IABP) support, and inotrope usage were significantly associated with the development of mesenteric ischemia; however, other intraoperative factors including the type of cardiac surgery and duration of aortic cross-clamping had varying levels of reported significance. There were discrepancies in the reported significance of leukocytosis and metabolic acidosis (pH <7.3) as postoperative markers. Postoperative vasopressor use, prolonged ventilation time, and elevation in lactate, transaminases, creatinine, and intestinal fatty acid-binding protein (IFABP) levels were found to be strongly associated with bowel ischemia. CONCLUSION: This systematic review found the strongest associations of mesenteric ischemia postcardiac surgery to be advanced age, CPB time, rise in lactate, transaminases, creatinine, and IFABP. IABP support, vasopressor, and inotrope use as well as prolonged ventilation were strongly linked too.

Spontaneous transvaginal intestinal evisceration in case of long-standing uterine prolapse.

BACKGROUND: Transvaginal intestinal evisceration is an extremely rare surgical emergency with potentially fatal consequences. Only a few more than 100 cases with this pathology have been described in the literature. Aetiology is also unclear and multifactoral. CASE PRESENTATION: We report the case of an 80-year-old female who presented with sudden severe abdominal pain and spontaneous small bowel evisceration through the vagina along with associated high-grade uterine prolapse. The loops and their mesentery appeared edematous, thickened and dusky, but without apparent necrosis. An urgent laparotomy was performed with subsequent reduction of the prolapsed small bowel into the abdomen, hysterectomy, partial resection of the vagina and vaginal closure. Additional cholecystectomy was necessary because of the visible pathologic changes of the gallbladder. The postoperative period was uneventful. The unique feature of our case is that there was no trigger factor (trauma, constipation or a coughing episode that would increase the intra-abdominal pressure), provoking the vaginal rupture and intestinal evisceration through it in the context of pelvic floor weakness. CONCLUSIONS: Early detection and surgical management are crucial for preventing bowel ischemia and abdominal sepsis. If the eviscerated intestine is ischaemic and non-viable, this requires resection and anastomosis. The approach should be individualized and performed by a multidisciplinary team.

Comprehensive review of acute small bowel ischemia: CT imaging findings, pearls, and pitfalls.

Acute small bowel ischemia is a life-threatening condition with a high mortality rate due to its lack of specific symptoms and laboratory profile, which render difficulty in establishing early diagnosis. The etiology of acute small bowel ischemia includes occlusive forms (arterial embolism, arterial thrombosis, and venous thrombosis) and nonocclusive mesenteric ischemia, of which arterial causes are far more common than venous causes. CT, the mainstay of accurate diagnoses, allows the identification of the features of vascular abnormalities and intestinal ischemic injuries, and helps clinicians to restore intestinal blood flow. Without treatment, the prognosis for acute small bowel ischemia is poor. A high index of suspicion and familiarity with the CT spectral findings of bowel ischemia are required to ensure rapid recognition of this condition.

Diagnosis of acute mesenteric ischemia assisted by dual-energy CT: a case report.

In this case report, dual-energy CT was critical in the diagnosis of acute mesenteric ischemia by differentiating normal contrast-enhanced bowel and hemorrhagic necrosis. Iodine map showed a segment of small bowel with minimal contrast enhancement, and virtual non-contrast imaging revealed hyperattenuating bowel. This finding changed management for the patient and prevented complications from impending bowel perforation. Histopathological analysis confirmed hemorrhagic necrosis of the bowel segment. In cases of suspected bowel ischemia, dual-energy CT can distinguish bowel wall hemorrhage from contrast enhancement and allow for accurate diagnosis.

Covered endovascular reconstruction of the aortic bifurcation associated to a snorkel technique for inferior mesenteric artery preservation.

Aortic distal occlusion has been usually treated by open surgery. A persisting patent and overdeveloped inferior mesenteric artery (IMA) suggests a significant participation in the bowel circulation. Coverage of the inferior mesenteric artery (IMA) origin could compromise the bowel circulation. Covered endovascular reconstruction of the aortic bifurcation (CERAB) is a proven and guideline-suggested alternative for revascularization of the distal aortic occlusion. CERAB associated to a snorkel to the IMA aims to reduce the risk of bowel ischemia keeping and percutaneous and minimal invasive approach.

Impact of Protocol Utilizing Water-Soluble Contrast for Adhesive Small Bowel Obstruction.

INTRODUCTION: Adhesive small bowel obstruction (ASBO) has classically been managed with nasogastric tube decompression and watchful waiting. Our group developed an evidence-based protocol to manage ASBO utilizing a water-soluble contrast (WSC) agent. We hypothesized the protocol would decrease the length of stay (LOS) for patients admitted with ASBO along with the time interval from admission to surgery. METHOD: From 2010 to 2018, a retrospective review was performed, including all patients admitted with a diagnosis of ASBO. These patients were divided into two groups: the preprotocol group included years 2010-2013 and the postprotocol group included years 2015-2018. A Student t-test and a two-proportion z-test were used for statistical analysis. RESULT: We captured 767 patients; 296 in the preprotocol group and 471 in the postprotocol group. We found a significant decrease in overall LOS between the preprotocol and postprotocol groups (6.56 d versus 4.08 d; P < 0.001) along with decreases in LOS for patients managed nonoperatively (5.36 d versus 3.42 d; P < 0.001) and operatively (16.09 d versus 9.47 d; P < 0.001). Time interval from admission to the operation was significantly decreased in the postprotocol group (3.79 d versus 2.10 d; P < 0.050). We identified a trend toward decreased rates of bowel ischemia and resections with our protocol. CONCLUSIONS: These results reaffirm previous reports of WSC's impact on overall LOS in ASBO while showing a similar impact on both operative and nonoperative groups. The decreased time interval between admission and operation may impact the incidence of bowel ischemia and resections.

Pneumatosis intestinalis and porto-mesenteric venous gas: a multicenter study.

BACKGROUND: Estimating the prognosis of patients with pneumatosis intestinalis (PI) and porto-mesenteric venous gas (PMVG) can be challenging. The purpose of this study was to refine prognostication to improve decision making in daily clinical routine. METHODS: A total of 290 patients with confirmed PI were included in the final analysis. The presence of PMVG and mortality (90d follow-up) were evaluated with regard to the influence of possible risk factors. Furthermore, a linear estimation model was devised combining significant parameters to calculate accuracies for predicting death in patients undergoing surgery by means of a defined operation point (ROC-analysis). RESULTS: Overall, 90d mortality was 55.2% (160/290). In patients with PI only, mortality was 46.5% (78/168) and increased significantly to 67.2% (82/122) in combination with PMVG (median survival: PI: 58d vs. PI and PMVG: 41d; p < 0.001). In the entire patient group, 53.5% (155/290) were treated surgically with a 90d mortality of 58.8% (91/155) in this latter group, while 90d mortality was 51.1% (69/135) in patients treated conservatively. In the patients who survived > 90d treated conservatively (24.9% of the entire collective; 72/290) PMVG/PI was defined as "benign"/reversible. PMVG, COPD, sepsis and a low platelet count were found to correlate with a worse prognosis helping to identify patients who might not profit from surgery, in this context our calculation model reaches accuracies of 97% specificity, 20% sensitivity, 90% PPV and 45% NPV. CONCLUSION: Although PI is associated with high morbidity and mortality, "benign causes" are common. However, in concomitant PMVG, mortality rates increase significantly. Our mathematical model could serve as a decision support tool to identify patients who are least likely to benefit from surgery, and to potentially reduce overtreatment in this subset of patients.

Clinical features of patients with hepatic portal venous gas.

BACKGROUND: Hepatic portal venous gas (HPVG) is a rare clinical condition that is caused by a variety of underlying diseases. However, the factors that would permit accurate identification of bowel ischemia, requiring surgery, in patients with HPVG have not been fully investigated. METHODS: Thirty patients that had been diagnosed with HPVG using computed tomography between 2010 and 2019 were allocated to two groups on the basis of clinical and intraoperative findings: those with (Group 1; n = 12 [40%]) and without (Group 2; n = 18 [60%]) bowel ischemia. Eleven patients underwent emergency surgery, and bowel ischemia was identified in eight of these (73%). Four patients in Group 1 were diagnosed with bowel ischemia, but treated palliatively because of their general condition. We compared the characteristics and outcomes of Groups 1 and 2 and identified possible prognostic factors for bowel ischemia. RESULTS: At admission, patients in Group 1 more commonly showed the peritoneal irritation sign, had lower base excess, higher lactate, and higher C-reactive protein, and more frequently had comorbid intestinal pneumatosis. Of the eight bowel ischemia surgery patients, four (50%) died, mainly because of anastomotic leak following bowel resection and primary anastomosis (3/4, 75%). All except one patient in Group 2, who presented with aspiration pneumonia, responded better to treatment. CONCLUSIONS: Earlier identification and grading of bowel ischemia according to the findings at admission should benefit patients with HPVG by reducing the incidence of unnecessary surgery and increasing the use of safer procedures, such as prophylactic stoma placement.

Arterial Gas Emboli Secondary to Portal Venous Gas Diagnosed With Point-of-Care Ultrasound: Case Report and Literature Review.

BACKGROUND: Portal venous gas (PVG) is a rarely observed clinical finding generally associated with intestinal ischemia. The proper clinical response to the finding of PVG depends somewhat on the setting in which it is observed. Here we describe a case in which extensive arterial gas emboli (AGE) were encountered during point-of-care ultrasound (POCUS) and subsequent computed tomography (CT) identified PVG secondary to gastric wall ischemia as the likely source. CASE REPORT: A 69-year-old woman with history of metastatic colon cancer presented to the emergency department (ED) with altered mental status. On arrival, she was hypotensive, hypothermic, cachectic, and with abdominal distension. POCUS was performed to evaluate the source of the patient's hypotension, revealing the presence of PVG, as well as gas bubbles in all four chambers of the heart and the aorta. CT scan revealed gastric wall ischemia and confirmed the presence of significant air emboli throughout the portal venous system. Given the overall poor prognosis, the decision was made to forego further chemotherapy or surgery and the patient died later that week while under hospice care. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: AGE can occur in the setting of PVG. This may cause multi-organ failure by disrupting blood flow to organs, especially in patients with circulatory dysfunction, such as shock. Depending on the setting in which it is diagnosed, early detection of PVG may expedite earlier assessments of a patient's negative prognosis or initiation of attempted life-saving treatment. In this case report, we show that POCUS can be used to obtain an expedited diagnosis in a critically ill patient.

Risk factors and outcomes for bowel ischemia after open and endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Bowel ischemia (BI) is a serious complication after abdominal aortic aneurysm (AAA) repair. We sought to identify the incidence and risk factors associated with the development of postoperative BI and the post-BI outcomes for patients undergoing open aortic repair (OAR) and endovascular aortic repair (EVAR) of AAAs. METHODS: A retrospective analysis was conducted for all patients who had undergone OAR or EVAR from 2003 to 2017 using the Vascular Quality Initiative database. Univariate (Student's t test, χ2, median) and multivariable (logistic regression) analyses were used to identify independent factors associated with postoperative BI and compare the post-BI in-hospital outcomes and mortality. RESULTS: We identified 45,474 patients who had undergone infrarenal AAA repair (OAR, 21.5%; EVAR, 78.5%). The overall incidence of postoperative BI was 1.9% (OAR, 6.2% vs EVAR, 0.8%; P < .001). OAR was associated with a threefold increased odds of BI compared with EVAR (adjusted odds ratio [aOR], 3.24; 95% confidence interval [CI], 2.49-4.22; P < .001). The independent factors associated with BI after OAR included older age (aOR per year of age, 1.02; 95% CI, 1.00-1.03), congestive heart failure (aOR, 1.44; 95% CI, 1.05-1.98), and ruptured aneurysm (aOR, 4.16; 95% CI, 2.98-5.81; P < .01 for all). We also found that transfusion ≥1 U (aOR, 1.69; 95% CI, 1.30-2.20), a transperitoneal approach (aOR, 2.13; 95% CI, 1.03-1.87), supraceliac clamping (aOR, 1.58; 95% CI, 1.08-2.33), and inferior mesenteric artery reimplantation (aOR, 1.41; 95% CI, 1.06-1.89) were associated with greater odds of BI after OAR (P < .01 for all). Similarly, we found that ruptured aneurysms, a longer operative time, and transfusion of ≥1 U of blood were associated with BI after EVAR (P < .001 for all). For both OAR and EVAR, the postoperative stay (median, 13 days [interquartile range (IQR), 7-26 days] vs 7 days [IQR, 5-10 days] and 11 days [IQR, 4-23 days] vs 1 day [IQR, 1-3 days], respectively) and 30-day mortality (35.0% vs 6.4% and 40.5% vs 1.9%, respectively) were significantly higher for patients with BI (P < .001 for all). The predictors of mortality for patients with BI were surgical management (aOR, 2.05; 95% CI, 1.28-3.30), older age (aOR, 1.05; 95% CI, 1.02-1.07), symptomatic aneurysm (aOR, 1.26; 95% CI, [0.60-2.62), ruptured aneurysm (aOR, 2.23; 95% CI, 1.43-3.48), longer operative time (aOR, 1.11; 95% CI, 1.01-1.22), and postoperative renal complications (aOR, 2.98; 95% CI, 1.80-4.96; P < .05 for all). CONCLUSIONS: Confirming the results from previous studies, we found that BI is more common after a ruptured aneurysm and OAR. Other associated intraoperative factors included a transperitoneal approach, supraceliac clamping, and a reimplanted inferior mesenteric artery. More than one third of patients who developed postoperative BI in our cohort had died within 30 days after AAA repair. The factors associated with mortality after BI included surgical management and postoperative renal failure. A high index of suspicion for the signs and symptoms of BI should be maintained postoperatively for patients presenting with the risk factors identified.

The Pathogenesis of Nonocclusive Mesenteric Ischemia: Implications for Research and Clinical Practice.

Nonocclusive mesenteric ischemia (NOMI) is a condition that can encompass ischemia, inflammation, and infarction of the intestinal wall. In contrast to most patients with acute mesenteric ischemia, NOMI is distinguished by patent arteries and veins. The clinical presentation of NOMI is often insidious and nonspecific, resulting in a delayed diagnosis. Patients most at risk are those with severe acute and critical disease, including major surgery and trauma. Nonocclusive mesenteric ischemia is part of a spectrum, from mild, asymptomatic, and an unexpected finding on CT scanning, through to those exhibiting abdominal distension and peritonitis. Severe NOMI is associated with a significant mortality rate. This review of NOMI pathophysiology was conducted to document current concepts and evidence, to examine the implications for diagnosis and treatment, and to identify gaps in knowledge that might direct future research. The key pathologic mechanisms involved in the genesis of NOMI represent an exaggerated normal physiological response to maintain perfusion of vital organs at the expense of mesenteric perfusion. A supply-demand mismatch develops in the intestine due to the development of persistent mesenteric vasoconstriction resulting in reduced blood flow and oxygen delivery to the intestine, particularly to the vulnerable superficial mucosa. This mismatch can be exacerbated by raised intra-abdominal pressure, enteral nutrition, and the use of certain vasoactive drugs, ultimately resulting in the development of intestinal ischemia. Strategies for prevention, early detection, and treatment are urgently needed.

Doppler ultrasonographic evaluation of celiac and mesenteric arteries in subjects with sickle cell disease.

Vasculopathy, as occurring in sickle cell disease (SCD), can affect celiac and mesenteric arteries and result in stenosis, with elevated peak systolic velocity (PSV) on Doppler ultrasonography. In six subjects with confirmed SCD in steady state, routine Doppler ultrasonographic examination discovered features of celiac artery (CA) or superior mesenteric artery (SMA) stenosis with CA PSV >200 cm/s (median = 222.8 cm/s; range = 201.5-427.1 cm/s) and/or SMA PSV >275 cm/s (median 183.2 cm/s; range = 87.8-289.3 cm/s). Among the six subjects, five had elevated soluble P-selectin values (median 72.55 ng/mL), while all six (100%) had elevated cystatin C levels (median 4.15 mg/L). Peripheral oxygen saturation was suboptimal in five subjects. All subjects had low hemoglobin concentration levels (median 8.5 g/dL) while four had elevated white blood cell count. Although vaso-occlusive crises result from microvessel occlusion, these findings at the macrovascular level suggest that SCD patients may also be vulnerable to mesenteric ischemic injury, especially in the setting of anemic heart failure from hemolysis.

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

OBJECTIVE: Outcomes after repair of ruptured abdominal aortic aneurysm (RAAA) have improved in the last decade. It is unknown whether this has resulted in a reduction of postoperative bowel ischemia (BI). The primary objective was to determine BI prevalence after RAAA repair. Secondary objectives were to determine its major sequelae and differences between open repair (OR) and endovascular aneurysm repair (EVAR). METHODS: This systematic review (PROSPERO CRD42017055920) followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. MEDLINE and Embase were searched for studies published from 2005 until 2018. The methodologic quality of observational studies was assessed with the Methodological Index for Non-Randomized Studies (MINORS) tool. The quality of the randomized controlled trials (RCTs) was assessed with the Cochrane Collaboration's tool for assessing risk of bias. BI prevalence and rates of BI as cause of death, reoperation, and bowel resection were estimated with meta-analyses with a random-effects model. Differences between OR and EVAR were estimated with pooled risk ratios with 95% confidence intervals (CIs). Changes over time were assessed with Spearman rank test (ρ). Publication bias was assessed with a funnel plot analysis. RESULTS: A total of 101 studies with 52,670 patients were included; 72 studies were retrospective cohort studies, 14 studies were prospective cohort studies, 12 studies were retrospective administrative database studies, and 3 studies were RCTs. The overall methodologic quality of the RCTs was high, but that of observational studies was low. The pooled prevalence of BI ranged from of 0.08 (95% CI, 0.07-0.09) in database studies to 0.10 (95% CI, 0.08-0.12) in cohort studies. The risk of BI was higher after OR than after EVAR (risk ratio, 1.79; 95% CI, 1.25-2.57). The pooled rate of BI as cause of death was 0.04 (95% CI, 0.03-0.05), and that of BI as cause of reoperation and bowel resection ranged between 0.05 and 0.07. BI prevalence did not change over time (ρ, -0.01; P = .93). The funnel plot analysis was highly suggestive of publication bias. CONCLUSIONS: The prevalence of clinically relevant BI after RAAA repair is approximately 10%. Approximately 5% of patients undergoing RAAA repair suffer from severe consequences of BI. BI is less prevalent after EVAR than after OR.