Multivessel coronary artery bypass grafting via small thoracotomy versus sternotomy (MIST): an...

Coronary artery bypass grafting (CABG) is a common but invasive operation traditionally performed through a median sternotomy. Minimally invasive cardiac surgery (MICS) CABG via small thoracotomy might improve postoperative recovery, but randomised evidence has been scarce. We aimed to compare patient-reported recovery after MICS CABG versus sternotomy CABG in patients with multivessel coronary artery disease and to describe clinical and safety outcomes.

MIST was an investigator-initiated, international, open-label, randomised controlled trial done at seven centres (four academic hospitals and three community hospitals) in Canada, India, China, Germany, the USA, and Japan. Patients referred to participating surgeons for CABG were eligible if they were aged 18 years or older; had angiographically confirmed multivessel coronary artery disease, defined as lesions of at least 70% stenosis in at least two major epicardial vessels and at least two separate coronary artery territories (left anterior descending artery, left circumflex artery, or right coronary artery) or left main coronary stenosis of 50% or more; and were suitable for coronary surgery both with sternotomy CABG and MICS CABG. Patients who were haemodynamically compromised, had contraindications to either approach, had had previous cardiac surgery, or required concomitant procedures were excluded. Eligible patients were randomly assigned (1:1) to MICS CABG or sternotomy CABG by a central, web-based system, stratified by centre, with block sizes of four and six. The primary endpoint was patient-reported physical recovery at 1 month, assessed by the 36-item Short Form Health Survey Physical Component Summary (SF-36 PCS) score. The primary analysis was by intention to treat; safety analyses were done according to treatment received. Missing 1-month questionnaire data were handled by multiple imputation. The trial was registered with ClinicalTrials.gov (NCT03447938), and is closed to recruitment.

Between Aug 24, 2018, and Nov 26, 2024, 176 patients were enrolled, 170 of whom were randomly assigned to MICS CABG (n=86) or sternotomy CABG (n=84). The median age of patients was 67·0 years (IQR 61·0-72·0), 154 (91%) patients were male, and 16 (9%) were female. At 1 month after surgery, SF-36 PCS scores were significantly higher in the MICS CABG group than in the sternotomy CABG group (mean 45·1 [SD 8·0] vs 42·2 [9·1]; mean difference 2·9 [95% CI 0·3-5·5]; p=0·031). Clinical and safety follow-up at 1 month was complete in all patients; 12-month clinical and safety follow-up was complete in all except three patients in the sternotomy CABG group. Up to 12 months after surgery, there were no deaths or strokes in either group; one major adverse cardiac or cerebrovascular event occurred in the MICS CABG group before 1 month and none in the sternotomy CABG group.

For selected patients with multivessel coronary artery disease, MICS CABG performed by experienced teams improved patient-reported physical recovery at 1 month compared with sternotomy CABG, with no apparent safety penalty through to 12 months. These findings support consideration of MICS CABG in appropriately selected patients treated by experienced teams, and further studies of implementation, recovery pathways, and long-term outcomes.

Medtronic.