Do we have enough evidence for minimally-invasive cardiac surgery? A critical review of scientific and non-scientific information.

Reducing surgical trauma by minimizing skin incisions has transformed abdominal surgery resulting in significant improvements in outcome. In cardiac surgery, such efforts have also been made, but similar benefits could not be demonstrated. In addition, any potential benefit comes at the cost of increased cardiopulmonary bypass and clamp times, leading to questions regarding the safety of minimally invasive cardiac surgery (MICS). Nevertheless, outcomes have been equivalent to matched sternotomy cases and there is no doubt that the number of patients undergoing minimally-invasive mitral or aortic procedures is slowly increasing. To date almost half of all isolated mitral cases in Germany and roughly one fourth in the USA are performed through a minimized access. These numbers were less than half 10 years ago. So how can this development be justified, if the evidence for it seems to be questionable or even missing? We will attempt to provide some answers to this question by critically reviewing the available publications and by looking at the topic from other perspectives, including from a competitive and a patient standpoint. We will conclude that there is enough evidence to support minimally-invasive access as the primary approach to a valve in the majority of patients. We will further suggest that modern cardiac surgery may have difficulties to prevail in its full width, if these novel techniques are not embraced. Finally, we will demonstrate that minimally invasive cardiac surgery is associated with substantial improvements in patient care, however, in areas that are unlikely to be tested with randomized controlled trials.