Acute Mesenteric Ischemia Management (ESVS 2017)

Algorithm Steps

1. ▶

   Start

   Suspected Acute Mesenteric Ischemia

   Severe abdominal pain out of proportion to exam, especially with vascular/cardiac history

   1. ●

      Action

      Clinical Recognition - High Index of Suspicion

      Classic presentation often absent

      • Sudden severe abdominal pain (80%)
      • Pain out of proportion to physical exam
      • Risk factors: AF, recent MI, CHF, atherosclerosis, hypercoagulable
      • GI emptying (vomiting, diarrhea early)
      • Peritonitis = late sign (bowel necrosis)
      1. ●

         Action

         Laboratory Studies

         Supportive but not diagnostic

         • Lactate (elevated but non-specific)
         • D-dimer (elevated in most cases)
         • WBC (often elevated)
         • Metabolic acidosis (late)
         • Normal labs do NOT rule out AMI
         1. ◆

            Decision

            AMI Subtype

            Determines treatment approach

            • Arterial embolism (~50%): AF, abrupt onset
            • Arterial thrombosis (~25%): atherosclerosis, subacute
            • MVT (~10%): hypercoagulable, portal HTN
            • NOMI (~15%): hypoperfusion, vasoconstrictors
            1. ●

               Action

               Immediate Resuscitation

               Start in parallel with workup

               • IV fluids - aggressive resuscitation
               • Correct acidosis/electrolytes
               • Broad-spectrum antibiotics
               • Anticoagulation (UFH) unless contraindicated
               • NG decompression
               • Avoid vasopressors if possible (worsen ischemia)
               1. ◆

                  Decision

                  Signs of Bowel Necrosis/Peritonitis?

                  Peritoneal signs, free air, pneumatosis

                  1. ⚠

                     Warning

                     ⚠️ Emergent Laparotomy

                     Necrotic bowel requires surgical resection

                     • Resect non-viable bowel
                     • Revascularization (embolectomy, bypass)
                     • Second-look laparotomy at 24-48h
                     • Damage control if unstable
                     • Mortality 50-80%
                     1. ●

                        Action

                        Post-Treatment Care

                        ICU monitoring, nutrition, complications

                        • ICU monitoring
                        • Second-look surgery if needed
                        • Short bowel syndrome risk if extensive resection
                        • Long-term anticoagulation
                        • Address underlying cause (AF, hypercoagulable workup)
                        1. ✓

                           Outcome

                           Survival

                           Early diagnosis critical - overall mortality 50-80%

                        2. ✓

                           Outcome

                           Short Bowel Syndrome

                           If extensive resection required - may need long-term TPN

                  2. ●

                     Action

                     Endovascular/Hybrid Approach

                     If no peritonitis and viable bowel

                     • Catheter-directed thrombolysis
                     • Mechanical thrombectomy
                     • Angioplasty + stenting
                     • May combine with laparoscopy to assess bowel
                     • Consider surgical backup
                  3. ●

                     Action

                     MVT-Specific Treatment

                     Anticoagulation is primary therapy

                     • Systemic anticoagulation (UFH → LMWH/warfarin/DOAC)
                     • Duration: 6+ months (often lifelong)
                     • Catheter-directed thrombolysis if progressing
                     • Surgery only if bowel necrosis
            2. ●

               Action

               NOMI Treatment

               Non-occlusive mesenteric ischemia

               • Treat underlying cause (shock, CHF)
               • Discontinue vasoconstrictors if possible
               • Intra-arterial papaverine/vasodilators
               • Optimize cardiac output
               • Surgery if bowel necrosis develops
      2. ●

         Action

         CT Angiography (CTA)

         Gold standard - obtain URGENTLY

         • Arterial + portal venous phase
         • Sensitivity/specificity >95%
         • Shows: SMA occlusion, bowel wall changes, pneumatosis
         • MVT: venous thrombus, bowel edema
         • Do NOT delay for other studies