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Indications & Contraindications
AMI vs CMI, etiologies, patient selection
Acute Mesenteric Ischemia (AMI)
- Embolic (40–50%) — most common; cardiac source (atrial fibrillation, post-MI); abrupt onset severe pain out of proportion to exam; SMA occlusion typically ≥3 cm from origin
- Thrombotic (25%) — acute-on-chronic atherosclerotic disease; occlusion within 1–2 cm of SMA origin; often history of postprandial pain (intestinal angina); collaterals present
- Nonocclusive (NOMI) (20–30%) — prolonged hypotension, vasopressors, digitalis/dopamine use; diffuse mesenteric vasospasm at branch points; no focal occlusion
- Mesenteric venous thrombosis (<5%) — portal hypertension, hypercoagulable states, abdominal inflammation, oral contraceptives
- Aortic dissection (<5%) — flap extending into SMA; true/false lumen compromise
Chronic Mesenteric Ischemia (CMI)
- Postprandial pain — crampy, dull; begins shortly after eating, lasts 1–2 hours
- Weight loss — present in ~80% of patients
- “Food fear” / food aversion — patients avoid eating due to anticipated pain; pathognomonic for CMI
- Intestinal angina — classic description; insufficient splanchnic blood flow during periods of heightened demand
- Atherosclerotic narrowing of ≥2 of 3 mesenteric vessels (celiac, SMA, IMA) classically required before symptom onset
- Other etiologies: fibromuscular dysplasia, vasculitis, post-surgical intimal hyperplasia
- More common in women (more acute aortomesenteric angle)
Contraindications
- Peritonitis / frank bowel infarction — requires surgical exploration and bowel resection first; endovascular alone insufficient
- No suitable vascular access (severe aortoiliac occlusive disease without upper extremity alternative)
- Uncorrectable coagulopathy
- Severe contrast allergy without adequate premedication
- Relative: Median arcuate ligament compression — surgical decompression preferred over stenting (high stent fracture rate from extrinsic compression)
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Pre-Procedure Planning
Imaging, labs, differentiation of acute vs chronic workup
Imaging
- CTA abdomen/pelvis with arterial phase — initial diagnostic exam of choice for both AMI and CMI; identifies stenosis/occlusion location, collateral pathways, bowel wall changes
- Look for: pneumatosis, portal venous gas, bowel wall thickening/enhancement (AMI signs of infarction)
- Sagittal reconstructions: evaluate ostial disease of celiac, SMA, IMA
- MRA: alternative when CTA contraindicated (eGFR 30–60); limited in small vessel disease and bowel assessment
- Duplex ultrasound (CMI workup): fasting and postprandial states; PSV and EDV assessment; inexpensive screening tool
Labs & Patient Prep
- AMI labs: CBC, CMP with liver enzymes, lipase, serum lactate, coagulation panel (PT/INR, aPTT), D-dimer, type & screen
- CMI labs: CBC, BMP, coagulation panel, type & screen
- Elevated WBC, lactate, and liver enzymes consistent with AMI — markedly elevated lactate with peritoneal signs is an ominous combination
- NPO 6–8 hours (if elective CMI); AMI is emergent — do not delay for NPO status
- IV access ×2; arterial line for AMI cases
- Echocardiogram or cardiac CTA (AMI embolic): rule out cardiac chamber thrombus before thrombolysis
CTA reviewed. Location and extent of stenosis/occlusion identified. Bowel viability assessed. Collateral pathways mapped. Access vessels evaluated.
Labs obtained. Lactate, CBC, CMP, coags, type & screen. Lactate trending monitored for AMI patients.
Multidisciplinary discussion. Surgery and critical care teams involved in AMI decision-making; hybrid OR availability confirmed if needed.
Consent obtained. Key risks: bowel infarction despite intervention, reperfusion injury, distal embolization, access site complications, contrast nephropathy, need for surgical exploration.
Antibiotics administered (AMI). Broad-spectrum coverage (piperacillin-tazobactam or equivalent) — bowel mucosal breakdown risk with bacterial translocation.
Anticoagulation planned. IV heparin 3000–5000 IU; target ACT >220 seconds during procedure.
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Relevant Anatomy
Mesenteric vessels, collateral pathways, SMA branches
Celiac Trunk
- Origin: anterior aorta at T12–L1
- Branches: left gastric, splenic, common hepatic arteries
- Supplies: stomach, liver, spleen, proximal duodenum, pancreas
- May be compressed by median arcuate ligament
Superior Mesenteric Artery (SMA)
▶ SMA anatomy — normal branching pattern
Normal SMA anatomy: jejunal branches left, ileocolic right, middle and right colic variable — map this before intervention to understand territory at risk.
- Origin: anterior aorta at L1, ~1 cm below celiac trunk
- Branches: inferior pancreaticoduodenal, jejunal, ileal, ileocolic, right colic, middle colic arteries
- Supplies: distal duodenum to splenic flexure of colon
- Primary target vessel in both AMI and CMI interventions
Inferior Mesenteric Artery (IMA)
- Origin: anterior aorta at L3
- Branches: left colic, sigmoidal, superior rectal arteries
- Supplies: splenic flexure to proximal rectum
- Smallest of the three; may require 0.014–0.018″ systems
Critical Collateral Pathways
| Collateral | Connects | Clinical Significance |
|---|---|---|
| Pancreaticoduodenal arcade | Celiac (GDA) ↔ SMA (inferior pancreaticoduodenal) | Primary celiac–SMA collateral; dilated arcade on CTA suggests proximal stenosis |
| Arc of Riolan (meandering mesenteric artery) | SMA (middle colic) ↔ IMA (left colic) | Central anastomosis; critical when SMA or IMA occluded |
| Marginal artery of Drummond | SMA ↔ IMA along colonic mesenteric border | Runs along mesenteric border of colon; variable at splenic flexure (Griffith point) |
| Arc of Buhler | Celiac ↔ SMA (rare embryologic variant) | Direct communication; present in ~2% of patients |
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Supplies & Technique
Equipment, AMI intervention, CMI stenting
Access & Catheters
- Femoral access: 7F 45-cm Flexor Ansel guiding sheath (Cook)
- Radial access (preferred over brachial): 6F radial sheath (Terumo); 90–110 cm Destination or Flexor Raabe long sheath for reach
- Selective catheters: Cobra 2, SOS Omni 2, RC 1, Simmons 1
- 7F ENVOY guiding catheter (for aspiration thrombectomy)
- Hydrophilic steerable guidewire (0.035″)
- Stiff exchange wire (Amplatz, Rosen)
Intervention Devices
- Balloon-expandable stents: Express LD (Boston Scientific), Herculink (Abbott) — preferred for ostial lesions
- Covered stents: iCast (Atrium) — for soft plaque, vessels <6 mm, or in-stent restenosis
- Low-profile angioplasty balloons: 0.014–0.018″ compatible; 2–3 mm for predilation, 4–8 mm for definitive
- AngioJet rheolytic thrombectomy system (Bayer) — for AMI embolic/thrombotic
- Infusion catheter (tPA delivery for AMI): multi-sidehole
- Aspiration catheters / Penumbra system
Medications
- IV heparin 3000–5000 IU (target ACT >220s)
- tPA (alteplase) 4–12 mg for catheter-directed thrombolysis (AMI)
- IA nitroglycerin 100–200 mcg boluses for vasospasm
- IA papaverine 45–60 mg bolus, then 1.0 mg/min infusion (NOMI and post-revascularization)
- Clopidogrel 300 mg loading + aspirin 325 mg post-stent
- Maintenance: clopidogrel 75 mg/d × 3–6 months + aspirin 81–325 mg/d for life
AMI Technique
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Arterial Access & Aortogram
Femoral access preferred. If aortoiliac occlusive disease or acutely downward-angled SMA origin prevents femoral approach: radial access (preferred over brachial) — lower complication rate, easier hemostasis, avoids median nerve. Use 6F radial sheath (Terumo) with 90–110 cm long sheath. AP and lateral aortograms to identify occlusion location and extent.
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Selective SMA Catheterization
Cobra 2, SOS Omni 2, or Simmons 1 catheter into SMA. Cross the lesion with hydrophilic wire. Exchange for stiff wire once lesion traversed.
▶ SMA angiogram — thrombus burden pre-thrombectomy
Acute SMA thrombus: column of intraluminal filling defect with poor perfusion to jejunal and ileal branches — quantify thrombus burden and identify residual flow before intervention.
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Thrombus Removal
Embolic AMI: Suction thrombectomy (advance sheath or guiding catheter) or AngioJet rheolytic thrombectomy. Catheter-directed thrombolysis: tPA 4–12 mg bolus into clot; consider power-pulse spray technique. Goal: rapidly re-establish proximal arterial flow.
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Treat Underlying Lesion (Thrombotic AMI)
After clot clearance, angioplasty with balloon-expandable stent for critical underlying atherosclerotic stenosis. Predilate with 2–3 mm balloon if heavily calcified. Post-dilate and flare proximal stent into aorta.
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Completion Angiogram & Adjuncts
Selective mesenteric angiogram to assess downstream circulation. IA papaverine 45–60 mg bolus into SMA for vasoconstriction relief. Persistent malperfusion + peritoneal signs + elevated lactate may prompt exploratory laparotomy.
CMI Technique
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Access & Diagnostic Aortogram
Femoral preferred; radial access if aortoiliac disease or acutely angled mesenteric origin (radial preferred over brachial — lower pseudoaneurysm/thrombosis risk). Place long sheath (7F 45–55 cm from femoral; 90 cm from radial) compatible with stent delivery. AP and lateral aortograms to identify all mesenteric origins.
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Selective Catheterization & Pressure Measurement
Catheterize target vessel (SMA, celiac, or IMA). Obtain translesion pressure gradient: ≥20 mmHg systolic at rest is significant; 10–20 mmHg is borderline (treat based on symptoms); <10 mmHg not significant.
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Lesion Crossing & Predilation
Hydrophilic wire to cross stenosis/occlusion. Predilate with 4 mm balloon. Advance sheath over deflating balloon through the lesion.
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Stent Deployment
Balloon-expandable stent (6–8 mm) for ostial lesions — preferred for precise placement. Confirm position with lateral injection through sheath sidearm before final deployment. Self-expanding stent may be used for trunk lesions. Post-dilate and flare proximal end (e.g., 8 mm balloon for 7 mm stent).
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Completion Angiogram & Antiplatelet Loading
Lateral and AP angiograms confirming patency, no dissection, good distal flow. Administer aspirin 325 mg + clopidogrel 300 mg loading dose in recovery.
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Landmarks & Imaging
Aortographic projections, selective catheterization, key angiographic views
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Lateral Aortogram
Critical projection for mesenteric intervention. Best view for celiac and SMA origins — profiles ostial disease that is often obscured on AP views. Identifies the degree of stenosis/occlusion at the vessel ostium. Set field of view to include T12 through L3.
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AP (Flush) Aortogram
Overview of mesenteric vascular anatomy, collateral pathways, and dynamic flow between territories. Identifies distal arterial disease and downstream perfusion adequacy. Useful for mapping arc of Riolan and marginal artery of Drummond when present.
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Selective SMA Angiogram
After catheterization, selective injection to evaluate: location/extent of thrombus (AMI), degree of stenosis (CMI), distal branch perfusion, venous return timing. Follow contrast through arterial and venous phases. Delayed venous filling suggests downstream ischemia.
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NOMI Findings
Diffuse vasospasm at and near branch points. Segmental or diffuse narrowing. Contrast reflux from SMA into aorta (high distal resistance). Asymmetric bowel perfusion and delayed mesenteric venous filling.
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Troubleshooting
Intraoperative challenges and solutions
Difficult SMA Cannulation
Cannot Engage the SMA Origin from Femoral Access
Try reverse-curve catheter (Simmons 1, SOS Omni 2) which may provide better purchase on downward-angled SMA. If acute angle persists, switch to radial access (right radial preferred; 6F sheath, 90–110 cm Destination or Flexor long sheath) — the coaxial approach from above provides a more favorable vector for acutely angled celiac/SMA origins. An 8F Morph steerable catheter (BioCardia) can navigate severe tortuosity and provide additional support for wire and device delivery.
No-Reflow / Persistent Malperfusion
Proximal Vessel Open but Distal Branches Remain Poorly Perfused
Administer IA papaverine 45–60 mg bolus directly into SMA (potent vasodilator; >90% first-pass hepatic clearance, low systemic risk). Consider additional thrombolysis for residual distal clot. If persistent malperfusion with peritoneal signs and rising lactate, proceed to exploratory laparotomy — do not delay surgical assessment.
Distal Embolization
Clot Fragments Migrate to Distal SMA Branches During Intervention
Aspirate through guiding catheter or sheath advanced beyond embolization site. Consider AngioJet or additional directed thrombolysis to affected branches. Distal protection devices remain controversial in mesenteric intervention but may be considered in cases with large thrombus burden. Adequate heparinization is critical to prevent propagation.
Vasospasm
Catheter-Induced or Post-Intervention Vasospasm
IA nitroglycerin 100–200 mcg bolus directly into SMA. May repeat every 3–5 minutes as needed. For sustained vasospasm (particularly NOMI), initiate IA papaverine infusion at 1.0 mg/min via indwelling SMA catheter. Monitor for systemic hypotension (uncommon with IA papaverine due to hepatic first-pass effect). Avoid vasopressin and alpha-agonists — worsen mesenteric ischemia.
Tight / Occluded Lesion (CMI)
Cannot Cross Chronic Occlusion with Standard Wire
Use hydrophilic steerable guidewire with aggressive tip shape. Predilate with low-profile 2–3 mm balloon (0.014–0.018″ system) to create initial channel. Advance sheath over deflating balloon. If unable to cross from femoral approach, switch to radial access for a coaxial, downgoing approach — more favorable wire/sheath angulation from above the lesion. Consider 0.018″ or 0.014″ platform for heavily calcified lesions.
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Complications
Procedural and post-procedural risks
Major Complications
- Bowel infarction despite intervention — may occur if revascularization is delayed or incomplete; persistent peritoneal signs and rising lactate post-procedure require surgical exploration
- Reperfusion injury — occurs after re-establishing inline flow; oxygen-rich blood interacts with locally produced free radicals; can cause additional cell death beyond initial ischemic insult; may lead to SIRS and multiorgan failure
- Distal embolization — clot fragments to branch vessels during thrombectomy or catheter manipulation; can convert partial ischemia to complete infarction
- Vessel dissection — wire or catheter injury to SMA intima; can be flow-limiting; may require stenting
- Stent thrombosis — acute or subacute; requires aggressive antiplatelet therapy and surveillance
Other Complications
- Access site complications — hematoma, pseudoaneurysm (increased risk with thrombolysis/anticoagulation); if radial access used: check post-procedure radial pulse + Allen test; if brachial used (avoid if possible): risk of thrombosis and median nerve compression
- Contrast-induced nephropathy — dehydration common in AMI patients exacerbates risk; pre/post hydration essential
- Stent dislodgement — balloon-expandable stent not fully deployed; careful positioning before final inflation
- In-stent restenosis (CMI) — intimal hyperplasia; risk factors: occlusions, lesions >3 cm, stent <5 mm diameter; treated with re-angioplasty or covered stent
- SIRS / sepsis — bacterial translocation from ischemic bowel; broad-spectrum antibiotics indicated for AMI
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Pearls & Pitfalls
High-yield clinical pearls and common mistakes
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“Time is bowel” — AMI is a vascular emergency analogous to stroke. Mortality approaches 90% with bowel infarction. Early clinical recognition and rapid intervention are the primary determinants of survival.
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“2 of 3 rule” for CMI — classically, stenosis or occlusion of at least 2 of the 3 mesenteric vessels (celiac, SMA, IMA) is required before CMI symptoms develop, owing to the robust collateral network. However, single-vessel disease can cause symptoms if collaterals are insufficient.
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Food fear is pathognomonic for CMI — patients avoid eating because they associate meals with pain. This, combined with significant weight loss (~80% of patients), strongly suggests chronic mesenteric ischemia.
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Lactate elevation in AMI is a late finding — normal lactate does NOT rule out mesenteric ischemia. By the time lactate is markedly elevated, bowel infarction may already be present. Elevated lactate + peritoneal signs = ominous combination.
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Embolic vs thrombotic AMI on imaging — embolic occlusion is typically ≥3 cm distal to SMA origin with convex filling defect and no collaterals (abrupt event). Thrombotic occlusion is within 1–2 cm of the SMA origin with formed collaterals (chronic underlying disease).
✦
Covered stents outperform bare metal in CMI — improved freedom from restenosis (92% vs 53%), symptom recurrence (92% vs 50%), and primary patency at 3 years (92% vs 52%). Consider covered stents especially for in-stent restenosis and vessels <6 mm.
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Do NOT use vasopressin or alpha-agonists in AMI patients — they worsen mesenteric vasoconstriction. If pressor support needed, use dopamine or dobutamine with reservation.
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Do NOT stent median arcuate ligament compression — extrinsic compression from diaphragmatic movement will cause stent fracture. Surgical decompression is the appropriate treatment.
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Do NOT delay surgery for endovascular-only approach when peritoneal signs are present — hybrid OR approach (endovascular revascularization followed by immediate laparotomy) is ideal for AMI with suspected bowel infarction.
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References & Resources
Primary sources and related procedures
Follow-up Protocol
- AMI: ICU admission; IV heparin; monitor lactate, WBC, hemodynamics; CTA at 1 month; duplex US 6–12 months; clopidogrel 75 mg/d × 3–6 months + aspirin 81–325 mg/d for life
- CMI: Outpatient clinic at 30 days (history, physical, duplex US); assess symptom relief, weight gain, food tolerance; repeat duplex at 6 months; yearly surveillance thereafter
- CTA or duplex for any recurrent symptoms; evaluate for in-stent restenosis
Primary References
- Stone JR, Wilkins LR. Acute mesenteric ischemia. Tech Vasc Interventional Rad. 2015;18:24–30.
- Wilkins LR, Stone JR. Chronic mesenteric ischemia. Tech Vasc Interventional Rad. 2015;18:31–37.
- Acosta S, Sonesson B, Resch T. Endovascular therapeutic approaches for acute superior mesenteric artery occlusion. Cardiovasc Intervent Radiol. 2009;32:896–905.
- Beaulieu RJ, Arnaoutakis KD, Abularrage CJ, et al. Comparison of open and endovascular treatment of acute mesenteric ischemia. J Vasc Surg. 2014;59:159–164.
- Oderich GS, Bower TC, Sullivan TM, et al. Open versus endovascular revascularization for chronic mesenteric ischemia: risk-stratified outcomes. J Vasc Surg. 2009;49:1472–1479.
- Oderich GS, Erdoes LS, Lesar C, et al. Comparison of covered stents versus bare metal stents for treatment of chronic atherosclerotic mesenteric arterial disease. J Vasc Surg. 2013;58:1316–1323.
- Hogendoorn W, Hunink MGM, Schlosser FJV, et al. A comparison of open and endovascular revascularization for chronic mesenteric ischemia in a clinical decision model. J Vasc Surg. 2014;60:715–725.