Incidence, diagnosis, management and outcome of acute mesenteric ischaemia: a prospective, multicentre observational study (AMESI Study)

BACKGROUND

The aim of this multicentre prospective observational study was to identify the incidence, patient characteristics, diagnostic pathway, management and outcome of acute mesenteric ischaemia (AMI).

METHODS

All adult patients with clinical suspicion of AMI admitted or transferred to 32 participating hospitals from 06.06.2022 to 05.04.2023 were included. Participants who were subsequently shown not to have AMI or had localized intestinal gangrene due to strangulating bowel obstruction had only baseline and outcome data collected.

RESULTS

AMI occurred in 0.038% of adult admissions in participating acute care hospitals worldwide. From a total of 705 included patients, 418 patients had confirmed AMI. In 69% AMI was the primary reason for admission, while in 31% AMI occurred after having been admitted with another diagnosis. Median time from onset of symptoms to hospital admission in patients admitted due to AMI was 24 h (interquartile range 9-48h) and time from admission to diagnosis was 6h (1-12 h). Occlusive arterial AMI was diagnosed in 231 (55.3%), venous in 73 (17.5%), non-occlusive (NOMI) in 55 (13.2%), other type in 11 (2.6%) and the subtype could not be classified in 48 (11.5%) patients. Surgery was the initial management in 242 (58%) patients, of which 59 (24.4%) underwent revascularization. Endovascular revascularization alone was carried out in 54 (13%), conservative treatment in 76 (18%) and palliative care in 46 (11%) patients. From patients with occlusive arterial AMI, revascularization was undertaken in 104 (45%), with 40 (38%) of them in one site admitting selected patients. Overall in-hospital and 90-day mortality of AMI was 49% and 53.3%, respectively, and among subtypes was lowest for venous AMI (13.7% and 16.4%) and highest for NOMI (72.7% and 74.5%). There was a high variability between participating sites for most variables studied.

CONCLUSIONS

The overall incidence of AMI and AMI subtypes varies worldwide, and case ascertainment is challenging. Pre-hospital delay in presentation was greater than delays after arriving at hospital. Surgery without revascularization was the most common management approach. Nearly half of the patients with AMI died during their index hospitalization. Together, these findings suggest a need for greater awareness of AMI, and better guidance in diagnosis and management.

TRIAL REGISTRATION

NCT05218863 (registered 19.01.2022).

Inferior Mesenteric Artery Snorkel for Endovascular Treatment of a Large Degenerating Saccular Aneurysm

Objective

Preservation of the inferior mesenteric artery (IMA) during endovascular aortic aneurysm repair (EVAR) is necessary for prevention of mesenteric ischaemia in the case of chronically occluded coeliac and superior mesenteric arteries (SMA). This case report presents an approach in a complex patient.

Methods

A 74 year old man with hepatitis C cirrhosis and recent non-ST elevation myocardial infarction presented with an infrarenal degenerating saccular aneurysm (58 mm), chronically occluded SMA and coeliac artery, and 9 mm IMA with high grade ostial stenosis. He also had concomitant atherosclerosis of the aorta with a narrow distal aortic lumen of 14 mm, which tapered to 11 mm at the aortic bifurcation. Endovascular attempts to cross long segment occlusions of the SMA and coeliac artery were unsuccessful. Thus, EVAR was performed using the unibody AFX2 endograft and chimney revascularisation of the IMA using a VBX stent graft. One year follow up demonstrated regression of the aneurysm sac to 53 mm with patent IMA graft and no endoleak.

Conclusion

Few reports have described techniques for endovascular preservation of the IMA, which is a necessary consideration in the context of coeliac and SMA occlusion. Because open surgery was not a good option for this patient, available endovascular options had to be weighed up. An added challenge was the exceptionally narrow aortic lumen in the context of aortic and iliac atherosclerotic disease. It was decided that the anatomy was prohibitive for a fenestrated design and extensive calcification was too limiting for gate cannulation of a modular graft. Thus a bifurcated unibody aortic endograft with chimney stent grafting of the IMA was successfully used as a definitive solution.

Preoperative findings on non-specific CT in patients with primary acute intestinal ischemia: a case-control study

PURPOSE

Primary acute intestinal ischaemia (AII) is an abdominal catastrophe caused by intravascular obstruction of blood supply. It is difficult to diagnose. Computerized tomography (CT) scan is the modality of choice for diagnostic evaluation. Majority of previous studies have evaluated CT findings in patients where AII was suspected. However, unveiling the unique radiological findings also in not initially suspected AII patients, might lead to the timely management of AII patients, and is the aim of this study.

METHODS

In a single-center, retrospective case-control study, preoperative radiological findings from abdominal CT scans in 48 patients with primary AII were compared with 80 non-ischemic controls. Radiological findings were analyzed using multivariable logistical regression with adjustment for age and gender and reported as odds ratios (OR) with 95% confidence intervals (CI) and p values.

RESULTS

Thirty-nine (81%) cases with AII were referred to an abdominal CT scan without a specific clinical suspicion of AII. Three main radiological categories (intestinal wall pathology [OR 7.4, CI 2.3-24.0, p value < 0.001], gastrointestinal vessel pathology [OR 19.3, CI 4.6-80.5, p value < 0.001) and intestinal diameter [OR 4.7, CI 1.6-13.4, p value 0.004]) were significantly different in AII patients. Subgroup analysis implied that pneumatosis intestinalis, increased contrast enhancement in the bowel wall, inferior mesenteric artery arteriosclerosis and colonic contraction were predictors of AII.

CONCLUSION

Radiological changes within the intestinal wall, luminal diameter and gastrointestinal vessels are independent predictors of AII. Awareness of these radiological findings, therefore, plays a central role in patients with an indistinct clinical picture in early recognition and treatment of a life-threatening AII.

TRIAL REGISTRATION NUMBER

NCT04361110 (April 24, 2020), retrospectively registered.

Retrograde Open Mesenteric Stenting for Acute and Chronic Mesenteric Ischaemia: Results from an Intestinal Stroke Centre

OBJECTIVE

To report the intra-operative adverse events (IOAEs) and the initial and one year outcomes of retrograde open mesenteric stenting (ROMS) using balloon expandable covered stents for acute and chronic mesenteric ischaemia.

METHODS

Clinical data and outcomes of all consecutive patients treated with ROMS for acute and chronic mesenteric ischaemia at an intestinal stroke centre between November 2012 and September 2019 were reviewed. ROMS was performed using balloon expandable covered stents. Endpoints included IOAEs, in hospital mortality, post-operative complications, and re-interventions. One year overall survival, freedom from re-intervention, primary patency and assisted primary patency rates were analysed using the Kaplan-Meier time to event method.

RESULTS

During the study period, 379 patients were referred to the centre for acute or chronic mesenteric ischaemia. Thirty-seven patients who underwent the ROMS procedure were included. All the patients had severe atherosclerotic mesenteric lesions. The ROMS technical success rate was 89% in this cohort. The rate of IOAEs was 19% and included four cases of retrograde recanalisation failure. All ROMS failures occurred in patients presenting with flush superior mesenteric artery occlusion and they were treated by mesenteric bypass. Ten patients (27%) underwent bowel resection, four of which resulted in a short bowel syndrome (11%). The in hospital mortality rate was 27%. Post-operative complications and re-intervention rates were 67% (n = 25) and 32% (n = 12), respectively. The median follow up was 20.2 months (interquartile range 29). The estimated one year overall survival for the cohort was 70.1% (95% confidence interval [CI] 52.5% - 82.2%). The estimated freedom from re-intervention at one year was 61.1% (95% CI 42.3 - 75.4). The one year primary patency and assisted primary patency rates were 84.54% (95% CI 63.34 - 94) and 92.4% (95% CI 72.8 - 98), respectively.

CONCLUSION

ROMS procedures offer acceptable one year outcomes for mesenteric ischaemia but are associated with frequent stent related complications. Precise pre-operative planning, high quality imaging, and meticulous stent placement techniques may limit the occurrence of such events.

Frequency, risk factors, and outcomes of non-occlusive mesenteric ischaemia after cardiac arrest

PURPOSE

Mesenteric ischaemia after successfully resuscitated cardiac arrest (CA) has been insufficiently studied. We aimed to assess the frequency, risk factors, and outcomes of non-occlusive mesenteric ischaemia (NOMI) after CA.

METHODS

We retrospectively included patients admitted to a CA centre with sustained return of spontaneous circulation between 2007 and 2017. NOMI was suspected based on clinical symptoms and classified as possible if no tests were feasible or the only test was a negative abdominal computed tomography (CT) scan and as confirmed if diagnosed by endoscopy, CT, or surgery.

RESULTS

Of 1343 patients, 82 (6%) had suspected NOMI, including 33 (2.5%) with confirmed NOMI. Investigations for suspected NOMI were done in 47/82 (57%) patients (CT, n = 30; lower digestive endoscopy, n = 14; and upper digestive endoscopy, n = 12); 11 patients underwent surgery. By multivariate analysis, factors associated with suspected NOMI were female sex (OR, 1.8; 95%CI, 1.1-2.9, p = 0.02), cardiovascular comorbidities (OR, 1.6; 95%CI, 1.0-2.7; p = 0.047), admission lactate >5 mmol/L (OR, 2.0; 95%CI, 1.2-3.4; p = 0.01), low flow >17 min (OR, 2.2; 95%CI, 1.3-3.8; p = 0.003), and inotropic score >7 μg/kg/min (OR, 1.8; 95%CI, 1.1-3.2; p = 0.03). ICU mortality was 96% (79/82), with 61% of patients dying from multi-organ failure (MOF) and 35% from post-anoxic brain injury. Of the eight patients who regained consciousness, 5 finally died from MOF, leaving 3 patients discharged alive from the ICU with a good neurologic outcome.

CONCLUSIONS

NOMI may affect 2.5-6% of patients after CA. Mortality was extremely high in patients, and very few survived with a good neurological outcome.

Extensive pneumatosis intestinalis and portal venous gas mimicking mesenteric ischaemia in a patient with SARS-CoV-2

We present the case of a critically ill 47-year-old man diagnosed with SARS-CoV-2 (COVID-19) who developed extensive pneumatosis intestinalis and portal venous gas in conjunction with an acute abdomen during the recovery phase of his acute lung injury. A non-surgical conservative approach was taken as the definitive surgical procedure; a complete small-bowel resection was deemed to be associated with an unacceptably high long-term morbidity. However, repeat computed tomography four days later showed complete resolution of the original computed tomography findings. Pneumatosis intestinalis from non-ischaemic origins has been described in association with norovirus and cytomegalovirus. To our knowledge, this is the first time that this has been described in COVID-19.

Spontaneous celiacomesenteric trunk dissection: Case report

•

As it is associated with the risk of mesenteric ischaemia or necrosis of the gastro-intestinal tract, the commun celiacomesenteric trunk should be kept in mind as a differential diagnosis for cases of recurrent non-specific abdominal pain.

•

When this vascular variant is observed, it is desirable; that a surgical treatment be planted to avoid any possible abdominal complications.

Introduction

The celiacomesenteric trunk (CMT) is one of the most striking among the different variations of the normal vascularisation of the gastro-intestinal tract. It is often accidentally discovered during autoptical dissections, angiography or abdominal computed tomography (CT).

Case presentation

A 27-year-old man was admitted to emergency for an acute abdominal pain. For his critical condition, the patient was immediately brought to the operating room. A extensive intestinal necrosis was found. Post-operator CT discovered a common CMT that is complicated by extended thrombosis. Despite all resuscitation measures, the patient died of septic shock two days later. An autopsy was performed showed that the main cause of intestinal ischemia was related to dissection of a common CMT.

Discussion

A CMT is a highly unusual variation in humans. It is usually asymptomatic and may be discovered incidentally during vascular surgery, radiologic imaging, or cadaver's dissection. Lesion of this entity can lead to serious gastrointestinal complications including necrosis. Different classifications are proposed in the literature.

Conclusion

As it is associated with the risk of mesenteric ischaemia, CMT should be kept in mind as a differential diagnosis for cases of recurrent non-specific abdominal pain.

Protective effect of hyperbaric oxygen treatment on rat intestinal mucosa after mesenteric ischaemia and reperfusion

INTRODUCTION

Mesenteric ischaemia results from a lack of adequate blood flow to and oxygenation of the mesentery and intestines. The aim of the present study was to evaluate the effect of hyperbaric oxygen treatment (HBOT) on the healing process in intestinal mucosa of rats undergoing mesenteric ischaemia and reperfusion.

METHODS

Thirty-two Wistar-Albino rats were divided into four groups of eight: 1) ischaemia/reperfusion (I/R); 2) sham operation; 3) I/R+HBOT started 6 hours after reperfusion; 4) I/R+HBOT started 12 hours after reperfusion. In the I/R groups, a vascular clamp was placed across the superior mesenteric artery to occlude arterial circulation for 60 minutes, followed by reperfusion. A dose of HBOT consisted of 100% oxygen breathing for 90 minutes at 2.5 atmospheres absolute pressure. Thirteen doses of HBOT were administered after ischaemia. The rats were sacrificed on the eighth day, and their intestinal tissues were harvested for histopathologic analysis. The tissue levels of catalase, malondialdehyde, and glutathione were determined.

RESULTS

The histopathological scores (HSCORE) were consistent with macroscopic examinations. The scores were significantly higher (worse) in Group 1 compared to Group 2, Group 3, and Group 4 (for all comparisons, P < 0.05). Group 4's HSCORE was significantly higher than those of Group 2 and Group 3 (for both comparisons P < 0.05). Group 3's HSCOREs were only marginally higher than Group 2. Group 3 exhibited higher glutathione levels than Group 1 (P < 0.05). There were no significant differences across the groups with respect to malondialdehyde and catalase levels.

CONCLUSION

A beneficial effect of HBOT was observed on oxidative stress and inflammation in acute mesenteric ischaemia-reperfusion.

Abdominal aortic aneurysm with occlusion of three primary mesenteric vessels treated by surgery with perfusion of the left iliac artery†

A 64-year-old woman who underwent thoraco-abdominal aortic replacement for a Crawford type II aneurysm 11 years ago was referred to our hospital because of a residual juxtarenal abdominal aortic aneurysm. The coeliac, superior mesenteric and inferior mesenteric arteries were occluded. Collateral vessels from the left internal iliac artery to these 3 mesenteric arteries had developed. We performed open aneurysm repair using an extracorporeal circuit to maintain collateral flow to these mesenteric arteries.

Acute mesenteric ischaemia: A case of expedited diagnosis and management using point-of-care ultrasound

INTRODUCTION

The term acute abdomen refers to a clinical syndrome of sudden onset, severe abdominal pain. The differential diagnosis for this presentation is broad, but most cases require emergent medical or surgical management. Especially in cases of ischaemic bowel, time to diagnosis can mean the difference between survival and death. As a result, mortality remains high in resource-limited settings.

CASE REPORT

We describe the case of a 28-year-old male who presented to an urban Ethiopian emergency centre with three days of vomiting, bloody diarrhoea, and abdominal pain. He collapsed in triage with weak pulses and an undetectable blood pressure. Point-of-care ultrasound revealed a hyperechoic, mobile mass in the left ventricle of the heart. Small bowel dilation and thickening was visualised throughout the abdomen. Mesenteric ischaemia was rapidly identified as the working diagnosis, prompting early surgical consultation and aggressive, goal-directed resuscitation.

DISCUSSION

Short of elucidating a definitive diagnosis, ultrasound narrowed the focus of an undifferentiated presentation and supported mobilisation for exploratory laparotomy. Ultimately, this circumvented several hours of time which is conventionally required to obtain computed tomography at this institution. As demonstrated in this case, point-of-care ultrasound can be life-saving in resource-limited settings where acquisition time for definitive imaging is often prohibitive.

Acute mesenteric ischaemia: a pictorial review

Abstract

Acute mesenteric ischaemia (AMI) is an uncommon cause of acute hospital admission with high mortality rates (50–90%) that requires early diagnosis and treatment. With the increase in average life expectancy, AMI represents one of the most threatening abdominal conditions in elderly patients. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can reverse this process leading to a full recovery, but the diagnosis of AMI is difficult. The failure to recognise AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Unfortunately, common CT findings in bowel ischaemia are not specific. Therefore, it is often a combination of nonspecific clinical, laboratory and radiological findings that helps most in the correct interpretation of CT findings. The purpose of this article is to provide an overview of the anatomy, physiology of mesenteric perfusion and discussions of causes, pathogenesis and CT findings in various types of acute bowel ischaemia. Familiarity with various imaging features of mesenteric injury is essential to make a timely diagnosis that will lead to improved patient outcomes.

Teaching Points

• AMI is a potentially life-threatening disorder whose prognosis depends on early recognition, accurate diagnosis and timely intervention.

• Arterial inflow occlusion due to thrombosis or embolisation is the most common cause of AMI.

• Four aetiological types of AMI have been associated with different characteristics and risk factors (EAMI, TAMI, VAMI and NOMI).

• Physical examination and laboratory findings are not sensitive or specific for diagnosing AMI; therefore, MDCT is still the first-line imaging method in suspected AMI.

• Although a number of scoring systems for prognosis have been proposed, these have not been validated in large-scale studies.

Endovascular Repair of Superior Mesenteric Arteriovenous Fistula Causing Early Mesenteric Steal Syndrome Following Abdominal Gunshot Injury

Introduction

Superior mesenteric arteriovenous fistulae (SMAVF) are rare, usually secondary to trauma or iatrogenic injury and typically present sometime after the initial insult.

Report

A 30 year old male underwent immediate laparotomy for abdominal gunshot injury. The small bowel mesentery contained a large haematoma and a palpable thrill. CT demonstrated a large SMAVF. At re-look laparotomy, small bowel ischaemia was noted and following this endovascular SMA stent graft insertion was performed, with excellent angiographic and clinical results.

Conclusion

The first report of immediate traumatic SMAVF leading to acute mesenteric steal syndrome and successful management with endovascular stent insertion is presented.

•

Traumatic superior mesenteric arteriovenous fistulae (SMAVF) are rare.

•

They often have a delayed presentation following initial insult.

•

Early SMAVF causing acute mesenteric steal syndrome is previously unreported.

•

This can be managed by a combination of surgery and endovascular intervention.

Long-Term Results of Endovascular Treatment of Atherosclerotic Stenoses or Occlusions of the Coeliac and Superior Mesenteric Artery in Patients With Mesenteric Ischaemia

INTRODUCTION

Over the past decade, primary percutaneous mesenteric artery stenting (PMAS) has become an alternative to open revascularisation for treatment of mesenteric ischaemia. Institutes have presented favourable short-term outcomes after PMAS, but there is a lack of data on long-term stent patency.

METHODS

One hundred and forty-one patients treated by PMAS for acute and chronic mesenteric ischaemia over an 8 year period were studied. Anatomical success was assessed by duplex ultrasound and/or CT angiography. A stenosis ≥70% was considered to be a failure.

RESULTS

Eighty-six coeliac arteries (CA) and 99 superior mesenteric arteries (SMA) were treated with PMAS in 141 patients. Nine CAs (10%) and 30 SMAs (30%) were occluded at the time of treatment. Median follow-up was 32 months (IQR 20-46). The overall primary patency rate at 12 and 60 months was 77.0% and 45.0%. The overall primary assisted patency rate was 90.3% and 69.8%. Overall secondary patency was 98.3% and 93.6%.

CONCLUSION

This study shows excellent long-term secondary patencies after PMAS, comparable with published data on long-term patencies after open surgical revascularisation.

Nutrient stimulation of mesenteric blood flow - implications for older critically ill patients

Nutrient ingestion induces a substantial increase in mesenteric blood flow. In older persons (aged ≥ 65 years), particularly those with chronic medical conditions, the cardiovascular compensatory response may be inadequate to maintain systemic blood pressure during mesenteric blood pooling, leading to postprandial hypotension. In older ambulatory persons, postprandial hypotension is an important pathophysiological condition associated with an increased propensity for syncope, falls, coronary vascular events, stroke and death. In older critically ill patients, the administration of enteral nutrition acutely increases mesenteric blood flow, but whether this pathophysiological response is protective, or precipitates mesenteric ischaemia, is unknown. There are an increasing number of older patients surviving admission to intensive care units, who are likely to be at increased risk of postprandial hypotension, both during, and after, their stay in hospital. In this review, we describe the prevalence, impact and mechanisms of postprandial hypotension in older people and provide an overview of the impact of postprandial hypotension on feeding prescriptions in older critically ill patients. Finally, we provide evidence that postprandial hypotension is likely to be an unrecognised problem in older survivors of critical illness and discuss potential options for management.

Acute abdominal pain in a man with Cushing syndrome

Arterial thrombosis or emboli have rarely been reported in Cushing syndrome (CS). Here we describe the first case of mesenteric ischaemia secondary to ventricular emboli in a patient with CS. Laboratory evaluation showed increased fibrinogen and factor VIII. Previous studies showed that venous thromboembolism (VTE) increases in CS. This case for the first time described arterial system thrombosis and emboli in a patient with adrenocorticotropin (ACTH)-dependent CS.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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