Coronary Artery Bypass Grafting (CABG) is one of the most common and effective surgeries for patients with advanced coronary artery disease. Surgeons may choose different types of grafts, most often using the LIMA (Left Internal Mammary Artery) or the more advanced BIMA (Bilateral Internal Mammary Arteries) technique.
- LIMA Bypass (Single Internal Mammary Artery – SIMA): Uses only the left internal mammary artery to bypass a blocked coronary artery. It is reliable and widely performed.
- BIMA Bypass (Bilateral Internal Mammary Arteries): Uses both the left and right mammary arteries, giving patients longer-lasting blood flow and higher graft survival.
Both are effective, but studies show that BIMA often provides superior long-term results, especially in younger patients and those with diabetes.
BIMA vs LIMA Bypass
The following table highlights the differences between BIMA and LIMA grafting in CABG surgery:
| Feature | BIMA (Bilateral Internal Mammary Artery) | LIMA (Single Internal Mammary Artery / SIMA) |
| Graft Patency | Higher long-term patency (15–20+ years). | Excellent patency but less durable than BIMA. |
| Survival Benefit | Superior survival has been shown in multiple studies. | Effective but slightly lower long-term outcomes. |
| Reoperation Rates | Fewer repeat interventions or stents are needed. | Higher chance of repeat surgery. |
| Wound Complications | Slightly higher risk of sternal wound issues, especially in diabetics. | Lower wound risk overall. |
| Minimally Invasive Options | It can be performed robotically or via minimally invasive CABG. | Less often performed minimally invasively. |
Who Benefits Most from Each Procedure?
BIMA Bypass – Best Candidates
- Younger patients: Longer graft durability means fewer future surgeries.
- Diabetic patients: Since diabetes accelerates artery disease, the superior protection of BIMA is a major advantage.
- Patients with multiple blockages: BIMA allows for more complete revascularization.
LIMA Bypass – Best Candidates
- Older or frailer patients may not tolerate longer surgical times.
- Patients with wound-healing concerns (obesity, poor immunity, advanced diabetes).
- Cases requiring shorter operative time, where safety outweighs long-term durability.
How Surgeons Reduce Risks in BIMA Surgery
One challenge with BIMA is the slightly higher risk of sternal wound infections (SWI), particularly in diabetics or obese patients. However, modern surgical methods significantly reduce this risk:
- Skeletonized Harvesting: Preserves the chest wall blood supply while preparing the arteries.
- Negative Pressure Wound Therapy (NPWT): Speeds healing and lowers infection risk.
- Enhanced Recovery Protocols: Better nutrition, strict glucose control, and infection-prevention measures.
With these strategies, BIMA surgery is now much safer and more widely performed.
Key Takeaway – Which Is Better, BIMA or LIMA?
● BIMA bypass provides superior long-term survival, graft patency, and reduced reoperations.
- LIMA bypass remains highly effective, especially for patients where minimizing risks and surgical time is a priority.
- The best choice depends on individual factors such as age, health status, diabetes, and surgical risk profile.
Conclusion: For many patients, particularly the young and diabetic, BIMA is considered the gold standard in CABG surgery.
Frequently Asked Questions (FAQ)
Q1. Is BIMA always better than LIMA?
Not always. While BIMA usually offers better long-term survival, some patients may face higher surgical or wound risks. Surgeons decide based on patient-specific factors.
Q2. How long do BIMA and LIMA grafts last?
- BIMA grafts: Often last 15–20+ years.
- LIMA grafts: Typically last 10–15 years, but still provide excellent results.
Q3. Is BIMA bypass riskier?
The surgery can be longer and carries a slightly higher infection risk, but modern techniques like skeletonized harvesting make it much safer today.
Q4. Can BIMA bypass be performed minimally invasively?
Yes. Robotic-assisted and minimally invasive CABG allow surgeons to perform BIMA grafting with smaller incisions, less pain, and quicker recovery.
Q5. Which procedure is more cost-effective?
Although BIMA may take more operative time initially, it usually saves money in the long run by reducing the need for repeat surgeries.
Conclusion
The BIMA vs LIMA bypass comparison makes it clear: both techniques are highly effective for treating coronary artery disease, but BIMA generally provides superior long-term protection.
With advancements in surgical technology and better post-op care, more cardiac surgeons now recommend BIMA grafting for younger and higher-risk patients, especially diabetics.