Aortoiliac occlusion for aortobifemoral bypass with coronary disease63-year-old man, 86 kg, for elective aortobifemoral bypass for aortoiliac occlusion

The patient

The examiner asks

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1. Consider

   What are your concerns?

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   • A 63-year-old with coronary disease, a stent and insulin-treated diabetes, for elective aortobifemoral bypass. Patient
   • His arterial disease carries three to five times the risk of MI, stroke and death. Disease
   • Myocardial ischaemia is the main danger in this operation.
   • Occlusive disease blunts the clamp response compared with aneurysm repair. Surgery

2. Prepare

   Take me through his cardiac risk assessment.

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   • Urgency: elective, so there's time to assess and optimise him. Stem trigger
   • Active cardiac conditions: none for him; no recent infarct, failing heart, tight valve or uncontrolled arrhythmia. Disease
   • RCRI: suprainguinal vascular surgery, coronary disease and insulin give him 3: elevated risk.
   • Functional capacity: claudication stops him at 50 metres, so I treat it as poor.
   • Decision: NT-proBNP; drug stress testing only where a result would alter his management.

3. Plan

   How do you prepare him and manage the clamp?

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   • Bisoprolol and statin continue; aspirin continues too, for his stent. Disease
   • Basal insulin cut by 20%; morning short-acting insulin omitted.
   • Epidural at least an hour before heparin; a bloody tap means a talk with the surgeon. Surgery
   • Heparin 50–100 IU/kg before the clamp, with ACT checked.
   • At clamping, I deepen and use the epidural to blunt the afterload rise.
   • An infrarenal clamp still cuts his renal blood flow by about 30%, so I keep him filled.
   • Before release: volume loaded, surgeon warned, clamp opened gradually.

4. Crisis

   On aortic clamping, BP rises to 196/104, HR 92, and V5 shows 2 mm ST depression. What do you do?

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   • Ischaemia from the afterload surge: tell the surgeon, 100% oxygen. Crisis
   • Deepen him and give nitroglycerin 50–100 mcg, then 0.5–5 mcg/kg/min.
   • If his rate climbs, esmolol 10–25 mg boluses.
   • Echo for new wall motion abnormalities.
   • Troponin and ECG after surgery to look for myocardial injury. After surgery

5. Crisis

   On day 1, with the epidural running and heparin prophylaxis started, he cannot lift his legs. BP 134/76. What do you do?

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   • I assume an epidural haematoma: infusion off now, catheter left where it is. (Crisis)
   • If strength doesn't return as the block wears off, the drug wasn't the cause.
   • Urgent MRI and neurosurgical decompression; recovery depends on speed.
   • Heparin stopped; coagulation and platelets checked.
   • Catheter removed only after heparin has been off 4–6 hours and clotting is normal.
   • Leg pulses checked too; cord ischaemia is very unlikely after this surgery.