Minimally invasive direct coronary artery bypass (MIDCAB) surgery was first described by Kolesov in 1964 and later promoted by Benetti in 1994. Since 2005, its use has expanded, becoming an increasingly popular technique. In most cases, the procedure involves performing a left internal thoracic artery (LITA) to left anterior descending (LAD) artery graft. However, the significant leap in benefit and impact has been achieved through the possibility of performing multiple arterial revascularizations via a minimally invasive approach. The ability to achieve complete revascularization while avoiding complications associated with sternotomy and aortic manipulation positions this technique as an attractive option in coronary surgery. Nonetheless, its high level of difficulty and steep learning curve mean it is currently feasible only in specialized centers and performed by a limited number of surgeons.

The article under discussion, published by one of these pioneering centers, presents the initial experience and outcomes of MIDCAB using multiple arterial grafts. The authors detail their introduction to minimally invasive cardiac surgery, including their technique and previous results with LITA-to-LAD revascularization, as well as their transition to multiple arterial revascularization.

In this cohort, the mean age was 66.7 years, with 12% of the patients being women. Of the 186 patients included, complete revascularization was not achieved in only 7 cases (4%). Regarding immediate postoperative complications, the 30-day mortality rate was 0.5% (1 patient), with one patient experiencing a stroke and 9.1% requiring reintubation due to respiratory failure. Additionally, 13 cardiac catheterizations were performed for suspected perioperative ischemia. In 11 cases (5.9%), graft failure was confirmed, necessitating repeat revascularization—either percutaneous or surgical. Twelve patients (6.5%) underwent re-thoracotomy for bleeding, and conversion to sternotomy was required in 2 cases.

With a mean follow-up of 3.6 years (ranging from 6 days to 7.9 years), 10 patients died, and 7 were lost to follow-up. The 5-year survival rate was 93.3%, with an 83.8% freedom from major adverse cardiac and cerebrovascular events (MACCE). Using Cox regression analysis, only age at surgery and dependence on preoperative dialysis emerged as independent predictors of mortality.

COMMENTARY:

Despite the adoption of MIDCAB as a routine myocardial revascularization technique in many centers, most procedures are limited to LITA-to-LAD grafting, either as a standalone procedure or within a hybrid approach. The learning curve remains long, and the technical difficulty is significant, even when “only” performing a LITA graft. The next level of complexity, as discussed here, involves bilateral internal thoracic artery (BITA) harvesting, creating a Y anastomosis between them, and performing sequential distal anastomoses to achieve complete revascularization through a left mini-thoracotomy. Consequently, this represents a highly complex procedure achieved only in select pioneering centers.

The exclusive use of arterial grafts has shown clear benefits in terms of durability and reduced adverse events, whether using dual mammary arteries (with robust supporting evidence) or a combination of LITA and radial artery. The authors present their initial experience with total arterial revascularization performed off-pump using either dual mammary arteries (88% of patients) or a combination of LITA and radial artery (12%).

Despite the promising technical outcomes of such a complex technique, several aspects of the article merit attention:

• The authors applied strict clinical and echocardiographic criteria for inclusion to ensure tolerance to single-lung ventilation and hemodynamic stability. Initially, only patients with a cardiothoracic index <50%, no ventricular dysfunction or dilation, good distal vessels, and a body mass index <30 kg/m² were included. Although the criteria were later relaxed, this strict selection raises the question of whether the patients most likely to benefit from minimally invasive access are precisely those excluded under these stringent requirements. Moreover, this strict selection limits the technique to high-volume centers capable of maintaining adequate procedural frequency.
• Most procedures were performed by the same cardiac surgeon, emphasizing the steep learning curve and challenges in generalizing these outcomes across multiple surgeons and centers.
• While the reported 30-day and mid-term mortality rates are comparable to non-minimally invasive revascularization, the authors reported slightly higher complication rates. A notable proportion of reoperations for bleeding was linked to prolonged surgical times, the use of single-lung ventilation, and a low tolerance for bleeding in their center. Additionally, graft failure occurred at a non-negligible rate, attributed to the initial learning phase, with 4 of the reported cases occurring among the first 35 patients. However, surgical wound infections and neurological complications remained low, at 1.1% and minimal rates, respectively.

This pioneering article on complete arterial revascularization via MIDCAB reports excellent outcomes. The authors are to be commended for their exemplary minimally invasive cardiac surgery program and their significant advances in the field of myocardial revascularization. While acknowledging the potential for higher complication rates during the initial learning phase, multiple arterial revascularization through MIDCAB emerges as a promising option within coronary surgery.

REFERENCES:

Verevkin A, Von Aspern K, Tolboom H, Gadelkarim I, Etz C, Misfeld M, et al. Total Arterial Multivessel Minimally Invasive Coronary Artery Bypass Surgery: 5-Year Outcomes. Ann Thorac Surg. 2024 Nov;118(5):1044-1051. doi: 10.1016/j.athoracsur.2024.06.037.

McGinn JT Jr, Usman S, Lapierre H, Pothula VR, Mesana TG, Ruel M. Minimally invasive coronary artery bypass grafting: dual-center experience in 450 consecutive patients. Circulation. 2009 Sep 15;120(11 Suppl):S78-84. doi: 10.1161/CIRCULATIONAHA.108.840041.

Kitahara H, Balkhy HH. Realizing the Benefits of Sternal-Sparing All-Arterial Multivessel Coronary Bypass Grafting! Ann Thorac Surg. 2024 Nov;118(5):1052-1053. doi: 10.1016/j.athoracsur.2024.07.040.