QUEBEC CITY — For eligible patients with multivessel coronary artery disease (CAD), minimally invasive coronary artery bypass grafting (MICS-CABG) yielded faster functional recovery and other benefits than traditional CABG (sternotomy), according to data presented at the Canadian Cardiovascular Congress (CCC) 2025. 

“Sternotomy is invasive,” said lead author Marc Ruel, MD, endowed chair and director of minimally invasive cardiac research in cardiac surgery at the University of Ottawa Heart Institute, Ottawa, during his presentation. Because it is invasive, it can have adverse consequences. As an example, he pointed to the DEDICATE trial, which compared transcatheter and surgical treatment of aortic-valve stenosis. At 30 days, surgery was associated with a 3.5% incidence of stroke or death. The incidence rose to 10% at 1 year. “To me,” he said, “that is an indicator that sternotomy is invasive.”

Longer Procedure, Better Recovery

Ruel and colleagues set out to determine whether nonsternotomy CABG, being less invasive, could be performed safely and offer additional clinical benefits in the multicenter, multinational MIST trial. This study took place in Canada, the US, Germany, India, China, and Japan from 2018 to 2024.

For the trial, patients referred for CABG for multivessel disease (≥ 70% occlusions in ≥ 2 territories or left main occlusion of ≥ 50%) were assessed to determine whether they were suitable candidates for MICS-CABG. If so, they were offered randomization to undergo either MICS-CABG or sternotomy CABG. Those who refused to be randomized underwent MICS-CABG and formed part of the MICS-CABG registry. 

The primary endpoint of the trial was the SF-36 Physical Component Summary (PCS) score at 1 month after surgery.

Overall, 170 eligible patients agreed to undergo randomization. The two groups were similar with respect to major risk factors such as smoking, BMI, diabetes, hypertension, and previous cardiac events, as well as the severity and extent of their CAD. In addition, the number of grafts and anastomoses and the percentage of arterial grafts were similar between the two groups.

As expected, procedure duration was longer with MICS-CABG (mean, 219.5 minutes vs 181.4 minutes), and total ventilation time was shorter (5.2 hours vs 11.6 hours).

One month after surgery, the PCS score was significantly better in the MICS-CABG group than in the sternotomy group (47.1 vs 44.3). The score remained higher after data were adjusted for surgery center and other key covariates.

Patients who underwent the minimally invasive procedure also had significantly fewer transfusions (12.8% vs 32.1%), and there was a trend toward a shorter average hospital stay (5.8 days vs 6.9 days). The rate of serious adverse events was similar in both groups. Subgroup analyses revealed no major differences in outcomes based on sex, comorbidities, or severity of CAD.

Ruel acknowledged the limitations of the trial, which included difficult recruitment, a paucity of female participants, and a lack of blinding. Outcomes will be assessed again at 5 years.

Outcomes Not Compromised

Emmanuel Moss, MD, a cardiac surgeon at McGill University in Montreal who chaired the session but was not involved in the trial, told Medscape Canada News that safely performing CABG in a minimally invasive manner is an important goal for cardiac surgery, as it is preferable to patients and reduces recovery time.

The MIST study helped demonstrate that it can be done in appropriate patients without compromising outcomes, he said. The findings still need to be replicated in a larger number of patients, however.

In addition, he pointed out, “The alternative to bypass surgery is coronary stents. These are obviously less invasive, but in general, they are associated with long-term outcomes that are not as good.” If patients could be offered a less invasive option such as MICS-CABG, they may be more likely to accept bypass surgery instead, he concluded.

The study received funding from Medtronic. Ruel reported receiving support from Medtronic and disclosed that he served as a surgery editor for Circulation, was past president of the Canadian Cardiovascular Society, and served as Canadian director of the Society of Thoracic Surgeons. Moss reported having no relevant financial relationships.