Randomised trials comparing conventional sternotomy to MIAVR face formidable challenges because of patient preference, surgeon bias and, importantly, the lack of a standardised surgical approach. Postoperative complications associated with a full sternotomy are practically possible with minimal invasive approach16 In theory, avoiding full sternotomy should contribute to better post-operative stability of the sternum and thereby prevent deep infection and preserve respiratory function and mobility in the immediate post-operative period. A smaller area of exposed sternal bone marrow and periosteum may also minimise bleeding. Several retrospective studies have shown that MIAVS reduces exposure of surgical trauma to the patient, post-operative pain, blood transfusion, risk of renal failure, times for mechanical ventilation and, therefore, reduces intensive care length of stay. The hospital postoperative length of stay is also diminished.19 Patient satisfaction and recovery to normal physical activity is also improved.5,20–22 Murtuza et al. published a meta-analysis of MIAVS versus conventional AVR studies. They included over 20 studies consisting of more than 4,000 patients.22MIAVR was associated with a significant reduction in mortality, shorter intensive care unit (ICU) and hospital lengths of stay and decreased ventilation times and transfusion rates.22
However, MIAVR was also associated with longer myocardial ischaemic, cardiopulmonary bypass and operative times compared with open procedures as a result of the steep learning curve involved, especially at the earliest stages of training.22 Since MIAVR procedures are usually technically more demanding, some surgeons argue that no compromises in quality should be allowed for the purpose of a smaller incision. It was also argued that de-airing at the end of such procedure could be incomplete.
An important fact to emphasise is that the outcome and quality of the procedure are comparable or superior to the conventional open or full sternotomy procedures, including the risks of cerebrovascular events. The recent introduction in the market of balloon expandable sutureless valves has enable a reducion of these times.
Another potential disadvantage of MIAVR is the morbidity associated with peripheral cannulation, which may cause wound infection, pseudoaneurysms and neurological events. Nevertheless the improvements in technique over time has decreased the morbidity of the procedure and allows surgeons to perform the procedure in high risk and elderly patients as more familiar approach and even better-than-predicted survival in this population.5 However, despite these procedures being potentially more expensive compared with full sternotomy procedures, the benefit is proven and it leads to a reduction in post-operative complications, shorter hospital stay and faster recovery, which should result in lower costs in the long term.