Minimally invasive cardiac surgery on par with median sternotomy in low-risk Asian patients

A single-centre study in Singapore has demonstrated the safety and efficacy of minimally invasive cardiac surgery (MICS), producing better outcomes than conventional median sternotomy (MS) procedures in certain respects.

“[O]ur study demonstrates that it is possible to establish a Singapore-based MICS programme comparable with other leading MICS programmes that is able to confer a high standard of care without compromising safety,” the researchers said.

The study included 4,453 patients who had undergone cardiac procedures such as heart valve replacement or repair, coronary artery bypass grafting, or atrial septal defect repair. Of the patients, 4,063 had undergone MS and 390 MICS between 2009 and 2020. Those with a high preoperative risk or those who required emergency operations were excluded from the study.

The number of MICS procedures performed, as well as MICS operations with two or more concomitant cardiac procedures, increased over the years, while postoperative length of stay decreased. [Singapore Med J 2021;doi:10.11622/smedj.2021136]

Patients who underwent MICS had shorter length of postoperative hospital stay (p<0.001) than those who underwent MS (p<0.001). On multivariate analysis, MICS patients had lower rates of atrial fibrillation (p=0.021), reoperation (p=0.028), and prolonged ventilation (p<0.001), but the rates of other postoperative complications were similar between those who underwent MICS and MS.

“Our study demonstrated comparable procedure and cardiopulmonary bypass duration, and shorter aortic cross clamp times in patients who underwent MICS,” the researchers said. “This is in contrast to the results of a systematic review and meta-analysis of eight studies on patients who underwent MICS, which revealed significantly longer operative time in the MICS group.” [Int J Cardiol 2016;223:554-560]

MICS procedures normally took longer during the early stages because of the steep learning curve warranted and the employment of long-shaft surgical instruments, which required a period of adaptation, but operation duration was bound to decrease with intense proctorship and increasing surgical experience. [Cochrane Database Syst Rev 2017;4:CD011793; Circulation 2000;102:2799-2802]

Of note, the shorter postoperative length of stay in MICS supported that of other studies. However, the overall postoperative length of stay of patients who underwent MICS was slightly higher in the current study than that reported in other MICS series. [Eur J Cardiothorac Surg 2012;42:648-652; Ann Surg 1997;225:805-811]

“The longer duration in our cohort is likely attributable to a variety of medical and social factors,” the researchers said. “Medical factors include that of anticoagulation to achieve therapeutic levels, and strict institutional discharge protocols centring on rehabilitation progress, which pose a challenge to discharging patients earlier into the community.”

The MICS programme in this single-centre study has shown steady growth, with support by educational, research, and innovation outputs, as well as robust organizational support and industry liaisons. In fact, it has already laid the foundation for two “Centres of Excellence” since the introduction of the programme and has attracted visiting teams, according to the researchers.

“The results of this study provide further evidence and support towards adopting the minimally invasive approach to cardiac surgery in a carefully selected group of cardiac patients in Singapore,” the researchers said. “More data in matched populations is required to provide further evidence regarding the benefits of MICS in our mixed-ethnic population.”