What is MIDCABG?
MIDCABG (Minimally Invasive Direct Coronary Artery Bypass) is a surgical technique that grafts the left internal mammary artery to the left anterior descending artery through a small left thoracotomy incision on the beating heart, without cardiopulmonary bypass or sternotomy. 1
Technical Approach
The procedure is performed through a left anterior small thoracotomy (LAST), typically via the fourth or fifth intercostal space, creating a 4-6 cm incision. 2, 3 The left internal mammary artery (LIMA) is harvested and anastomosed directly to the LAD artery while the heart continues beating, using pharmacologic bradycardia and mechanical stabilization devices. 4, 5
- The LIMA is typically mobilized from the fifth costal cartilage to the subclavian artery 6
- Anastomoses are performed under direct vision on the beating heart without cardioplegic arrest 6, 5
- Mechanical stabilizing devices are used to minimize cardiac motion during the anastomosis 4
Primary Indication
MIDCABG is specifically designed for isolated proximal LAD stenosis that is unsuitable for percutaneous intervention. 1, 5 The European Heart Journal notes that adoption has been slow partly due to the low incidence of isolated proximal LAD stenosis and the high technical demands of the procedure. 1
Clinical Outcomes
Early mortality ranges from 0-4.9%, with acceptable short-term graft patency, though concerns exist about long-term durability. 5 A systematic review found:
- Conversion to sternotomy/cardiopulmonary bypass occurs in 0-6.2% of cases 5
- Non-fatal myocardial infarction rates range from 0-3.1% 5
- Reintervention for graft failure is necessary in up to 8.9% of patients 5
One comparative study showed that at 6-month follow-up, 8% of MIDCABG patients had recurrent ischemia involving the LAD, primarily from anastomotic stricture. 6
Advantages Over Conventional CABG
MIDCABG reduces initial morbidity, hospital costs, and recovery time compared to traditional sternotomy CABG. 6 Specific benefits include:
- Lower transfusion requirements (17% vs 40% in sternotomy) 6
- Shorter postoperative intubation time (2.1 vs 12.6 hours) 6
- Reduced median hospital stay (4 days vs 7 days) 6
- Lower estimated hospital costs ($11,200 vs $15,600) 6
- Shorter time to return to work and higher patient satisfaction 1
Hybrid Revascularization Strategy
MIDCAB can be combined with percutaneous coronary intervention (PCI) for multivessel disease in a hybrid approach—LIMA to LAD via MIDCAB plus stenting of circumflex and/or right coronary arteries. 1 The European Heart Journal reports that 5-year survival with hybrid revascularization is comparable to off-pump CABG in both left main disease (88.6% vs 83.4%, P=0.55) and multivessel disease (86.8% vs 84.3%, P=0.61). 1
Important Caveats
The technical difficulty of performing precise anastomoses on a beating heart raises valid concerns about anastomotic quality and long-term patency. 4, 5 The procedure requires:
- Extensive surgeon experience and technical expertise 1
- Specialized equipment including mechanical stabilizers 4
- Careful patient selection for isolated LAD disease 5
Adoption remains limited—a 2002 survey found 80% of US surgeons perform fewer than five MIDCAB procedures annually. 1 The European Heart Journal emphasizes that randomized trials comparing MIDCAB (especially hybrid approaches) to conventional CABG are still lacking. 1