Predictors of Transmural Non-Occlusive Mesenteric Ischemia in ICU Patients With Suspected Acute Mesenteric Ischemia (AMESI-EST)

Mesenteric Ischemia in the ICU: A Prospective Observational Study Across Estonian Regional Hospitals

Acute mesenteric ischemia (AMI) is a rare but life-threatening condition associated with high mortality and major diagnostic challenges due to nonspecific clinical presentation and limited reliable biomarkers. Critically ill patients in the intensive care unit (ICU) are at particularly high risk of non-occlusive mesenteric ischemia (NOMI), a subtype of AMI characterized by impaired mesenteric perfusion without large-vessel occlusion. Despite advances in imaging, the diagnosis of NOMI remains difficult, and data specifically focusing on ICU patients with suspected AMI are limited.

This prospective observational multicenter study aims to identify independent predictors of transmural NOMI among ICU patients with suspected AMI. In addition, the study will describe demographics, comorbidities, clinical presentation, laboratory findings, diagnostic imaging, management strategies, and outcomes among ICU patients with NOMI, other forms of AMI, and patients with suspected but unconfirmed AMI. Consecutive adult ICU patients in whom clinical suspicion of AMI arises during ICU stay will be included across Estonian regional hospitals. The study is a local continuation of the international AMESI study, with a specific focus on critically ill ICU patients.

Study Overview

• Status: Recruiting
• Conditions: Acute Mesenteric Ischemia; Non-Occlusive Mesenteric Ischaemia (NOMI)
• Intervention / Treatment: Other: Observation

• Study Type: Observational
• Enrollment (Estimated): 150

Contacts and Locations

Study Locations

• Estonia
  • Tallinn
    • Tallinn, Tallinn, Estonia, 13419
      • Recruiting
      • North Estonia Medical Centre
      • Contact: Olga Kiss, MD; Phone Number: +372 617 1300; Email: Olga.Kiss@regionaalhaigla.ee
  • Tartu
    • Tartu, Tartu, Estonia, 50406
      • Recruiting
      • Tartu University Hospital
      • Contact: Vladislav Mihnovitš, MD; Phone Number: +372 7318111; Email: vladislav.mihnovits@kliinikum.ee

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

All adult patients who develop suspicion of acute mesenteric ischemia during their ICU stay will be included in the study. The study will take place in the ICUs of the two largest hospitals in Estonia: Tartu University Hospital and North Estonian Medical Centre.

Description

Inclusion criteria

- Adult ICU patients in whom clinical suspicion of acute mesenteric ischemia is raised during their ICU stay.

Exclusion criteria

• Patients who develop acute mesenteric ischemia outside of the intensive care unit,
• Confirmed strangulating bowel obstruction,
• Individuals younger than 18 years,
• Chronic mesenteric ischemia without an acute event.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients with suspected acute mesenteric ischemia in the ICU	Other: Observation; This is a prospective observational study on ICU patients with the suspicion of acute mesenteric ischemia. No intervention is done.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Predictors of transmural necrosis in NOMI - age-adjusted Charlson comorbidity index	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - age-adjusted Charlson comorbidity index (Range 0 - 37 points). A higher score indicates a higher chance of 10-year mortality.	Baseline
Predictors of transmural necrosis in NOMI patients - SOFA score	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Sequential Organ Failure Assessment (SOFA) score (Range 0 - 24 points). Higher scores indicate more severe organ dysfunction.	Baseline
Predictors of transmural necrosis in NOMI patients - GRV	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Gastric residual volume (GRV) greater than 500 ml at any point within the 48 hours prior to the suspicion of acute mesenteric ischemia (AMI) will be recorded as a Yes or No variable. A high GRV indicates feeding intolerance, which may suggest non-occlusive mesenteric ischemia. This is a retrospective variable. After a patient is enrolled in the study, the patient's ICU datasheet will be retrospectively analyzed to determine if there was a GRV above 500 ml. If such an event occurred within the 48 hours prior to inclusion, the variable will be considered positive (Yes); if not, it will be considered negative (No).	Baseline
Predictors of transmural ischemia in NOMI patients - bloody stool.	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Presence of bloody stool. Yes or No variable. Bloody stool might indicate gastrointestinal ischemia.	Baseline
Predictors of transmural ischemia in NOMI patients - cardiac arrest.	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Cardiac arrest. Yes or No variable. If the patient was hospitalised due to cardiac arrest, then Yes, if not, then No. Cardiac arrest is a risk factor for developing NOMI.	Baseline
Predictors of transmural ischemia in NOMI patients - RRT	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Need for renal replacement therapy (RRT) prior to suspicion of AMI. The variable is a Yes or No question. Once a patient is enrolled in the study, a retrospective analysis of their data sheet will be conducted to determine if the patient received renal replacement therapy (RRT) during their hospital stay prior to their inclusion in the study. RRT is a risk factor for developing non-occlusive mesenteric ischemia.	Baseline
Predictors of transmural ischemia in NOMI patients - WBC.	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Highest White blood cell (WBC) levels within 72 hours prior to suspicion of acute mesenteric ischemia. Units: 10*12 /L. The highest WBC value within the 72 hours prior to suspicion of AMI will be recorded. Higher values indicate a more severe inflammatory response.	Baseline
Predictors of transmural ischemia in NOMI patients - CRP	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - C-reactive protein (CRP). Units: mg/L. The highest CRP value within the 72 hours prior to suspicion of AMI will be recorded. Higher values indicate a severe inflammatory response.	Baseline
Predictors of transmural ischemia in NOMI patients - lactate	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Highest lactate value. Units: mmol/L. The highest lactate value within the 12 hours prior to suspicion of AMI will be recorded. Higher values indicate worse tissue perfusion.	Baseline
Predictors of transmural ischemia in NOMI patients - pneumatosis intestinalis	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Pneumatosis intestinalis. Yes or No variable.In patients suspected of acute mesenteric ischemia, the presence of pneumatosis intestinalis observed on computed tomography will be documented. The presence of pneumatosis intestinalis can indicate mesenteric ischemia.	Baseline
Predictors of transmural ischemia in NOMI patients - bowel wall enhancement	To identify independent predictors of transmural necrosis in patients with non-occlusive mesenteric ischemia. Variable: - Decreased bowel wall enhancement on the computed tomography. Yes or No variable. In patients suspected of acute mesenteric ischemia, the decrease in bowel wall enhancement observed on computed tomography will be documented. The decrease in bowel wall enhancement on CT can indicate mesenteric ischemia.	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
CT findings in patients with suspected AMI	Computed tomography variables in patients with suspicion of acute mesenteric ischemia will be analysed. Variables: Presence of bowel dilatation (Yes or No variable); Pathological bowel wall enhancement (categorization: absence or decrease enhancement; normal enhancement; increased enhancement); Presence of pneumatosis intestinalis (Yes or No variable); Presence of gas in the mesenteric or portal venous system (Yes or No variable); Thickening of the bowel wall (Yes or No variable) (small bowel > 3 mm, large bowel > 3 mm if distended or > 5 mm if not distended); Thinning of the bowel wall (Yes or No variable)	Baseline
Management of AMI patients	Rate of surgical, conservative, endovascular or palliative management	Baseline
30-day survival	30-day Survival of patients with suspicion of acute mesenteric ischemia in the ICU	30 days after admission
90-day survival	90-day Survival of patients with suspicion of acute mesenteric ischemia in the ICU	90 days after admission

Collaborators and Investigators

• Sponsor: University of Tartu

Study record dates

Study Major Dates

• Study Start (Actual): June 6, 2022
• Primary Completion (Estimated): June 5, 2026
• Study Completion (Estimated): September 5, 2026

Study Registration Dates

• First Submitted: May 10, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 28, 2026

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: predictors; Acute mesenteric ischemia; non-occlusive mesenteric ischemia; transmural necrosis
• Additional Relevant MeSH Terms: Investigative Techniques; Methods; Observation
• Other Study ID Numbers: AMESI-EST

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No