Perioperative management - Iliomesenteric venous bypass for occlusion of the superior mesenteric artery

• Intestinal angina due to short-segment stenosis of the superior mesenteric artery (SMA) close to its origin, or occlusion with inadequate collateral supply via the coeliac trunk
• Lack of indication for interventional treatment, e.g. in long-segment stenoses/occlusions at the origin of the SMA)
• Failure of interventional management

Video clip: SMA occlusion close to its origin with occlusion of the coeliac trunk

Grade of ischaemia and general indication for surgery

• Long-segment and multifocal stenoses of the SMA > 6 cm usually do not lend themselves to open repair
• Multisegment occlusive processes of the SMA, e.g. in thromboangiitis obliterans (Winiwarter-Buerger disease) or lupus erythematosus
• ASA IV
• COPD GOLD IV

Key aspects first:

1. Chronic intestinal ischaemia syndromes: Only diagnostic imaging yields useful insights!

2. Usually there are multiple (vascular) comorbidities -> detailed examination by vascular surgeons and angiologists.

3. The patient should undergo work-up to identify other abdominal diseases, especially to rule out malignancies.

4. Delayed diagnosis > 12 months because the disease is considered too late in the differential diagnosis.

Medical history

Typical triad in malperfusion of the SMA:

• postprandial abdominal pain starting shortly (about 20 min) after food intake and subsiding after 3-4 hours (intestinal angina)
• reactive restriction on food intake -> weight loss, muscle atrophy, asthenia ("small-meal syndrome")

Absence of weight loss does not rule out the diagnosis!

Ischaemia of the coeliac trunk distribution area results in nausea, vomiting and meteorism; constipation is more likely to result from disease of the inferior mesenteric artery.

Duplex ultrasonography for assessment of the intestinal vessels

• Stenosis typically at the ostium
• Increased flow velocity—flow velocities greater than 200 cm/s are considered pathognomonic for high-grade stenosis—as well as turbulent flow

CT angiography or MR angiography

• with image reconstruction

digital subtraction angiography of the intestinal arteries in 2 planes

• when planning an intervention

Abdominal ultrasonography

(Exercise) ECG

Chest X-ray

Laboratory panels

• Blood count, electrolytes, coagulation, renal retention parameters, blood lipids

Staged diagnostic approach to visceral ischaemia

• Ultrasound assessment of whether an autologous great saphenous vein is available as a graft (synthetic graft if required)
• Blood group typing, provide packed RBCs if needed
• Enema
• Indwelling urinary catheter

General surgical risks

• Major bleeding, blood transfusions, transmission of hepatitis/HIV through allogeneic blood transfusions
• Allergy/intolerance
• Wound infection
• Thrombosis/embolism
• Skin, vascular and nerve damage, e.g., due to patient positioning
• Keloids

Risks special to this procedure

• Incisional hernia
• Abdominal adhesions, ileus
• Intraoperative peripheral embolism into the iliac/leg vessels -> surgical intervention, in case of leg ischaemia up to amputation
• Massive infection → bleeding, peritonitis, sepsis; possible surgical revision with removal of the vascular graft
• Injury to neighbouring organs (ureter, bladder, bowel, liver, spleen); creation of an intestinal stoma
• Impaired perfusion or nerve injury of the spinal cord (paresis, erectile dysfunction)
• In case of autologous vein use: secondary bleeding, infection, keloid
• Intraoperative angiography: contrast agent → renal failure
• Bypass infection/stenosis → impaired perfusion of the affected organs, repeat intervention
• Impaired intestinal perfusion → impaired defecation, malabsorption, ischaemic colitis → resection, possibly creation of an intestinal stoma