Evolution in the Presentation, Treatment, and Outcomes of Patients with Acute Mesenteric Ischemia.

Objectives: Acute mesenteric ischemia (AMI) is a life-threatening condition associated with dismal outcomes. This study sought to evaluate the evolution of presentation, treatment, and outcomes of AMI over the past two decades.

Methods: AMI patients presenting at a single institution were reviewed (1993-2016). Venous thrombosis patients were excluded. Primary outcome was 30-day mortality. Patients were stratified by etiology and diagnosis date (before 2004 versus 2004 and later). Ordered logistic regression was performed for longitudinal temporal analysis.

Results: 303 patients were identified. AMI mechanisms included: embolic (49%), thrombotic (29%), and non-occlusive (NOMI) (22%). The majority were women (55%), 50% had atrial fibrillation, and 23% were on anticoagulation (AC) therapy. Mean age was 72±13 years. 345 procedures were performed in 242 patients: 321 open and 24 hybrid/endovascular. Among the 189 embolic/thrombotic patients who were managed operatively, 45% (n=85) underwent mesenteric revascularization while 39 (21%) had findings of non-survivable bowel necrosis (NSBN). Among the 104 patients who did not undergo revascularization, 64 (62%) died within 30-days compared to 36 out of 85 (42%) patients who were revascularized (P=0.01). 30-day mortality was 61% and stable over time (P=0.91); when stratified by AMI etiology, the thrombotic cohort had worse survival than embolic and NOMI patients (P=0.04). Since 2000, there was a significant decrease in the percentage of embolic AMI events (P=0.04). The percentage of patients who underwent operative management decreased also over time (P=0.01, 81% → 61%), which was correlated with an increasing number of patients being made comfort measures only (CMO) prior to surgical intervention (50% → 70%, P=0.02). The majority of patients (55%) were ultimately made CMO during their hospitalization. Predictors of 30-day mortality included a preoperative white blood cell count (WBC) ≥ 25 K/ µL. (OR 3.0, P=0.002) and lactate ≥ 2.3 mmol/L (OR 2.8, P=0.045). NSBN predictors included WBC ≥ 24 K/ µL. (OR 3.4 P=0.03) and lactate ≥ 3.8 mmol/L (OR 3.6, P=0.04).

Conclusions: Despite advances in critical care over the past 25 years, AMI continues to be associated with poor prognosis. The survival benefit observed in patients who undergo revascularization supports an aggressive approach towards early vascular intervention, although this requires further study. The importance of early diagnosis, prognostication and advanced directives is highlighted given the high morbidity, mortality and use of comfort measures associated with AMI.