Surgical Outcomes following Complex and High Risk Cardiac Surgery in Australia

Abstract

The population presenting for cardiac surgery today is more elderly and high risk. The objective of this thesis was to identify the outcomes following complex and high risk cardiac surgery and determine its feasibility, safety and reproducibility. Methods used were retrospective database studies (unadjusted and propensity matched studies), systematic review and meta-analysis as well as literature review. The main outcomes studied were perioperative mortality, stroke and long term survival. This dissertation discusses off pump (OPCAB) versus on pump (ONCAB) coronary revascularisation surgery; mitral valve (MV) repair versus replacement; surgical aortic valve replacement (sAVR) versus transcatheter aortic valve implantation (TAVI); aortic root replacement and valve-sparing aortic root reconstruction. On pump coronary artery bypass and OPCAB had similar postoperative mortality and stroke rates but there was a non-significant trend towards improved long term survival following OPCAB. Significant mortality benefit in patients with diabetes, left main disease and peripheral vascular disease and significant stroke benefit in patients with diabetes and peripheral vascular disease was seen post OPCAB. Overall, MV repair is superior to MV replacement, especially in the elective setting. In degenerative MR, there was a non significant trend towards improved short and long term outcomes following repair. In ischaemic MR, the outcomes were equivalent. The literature review on management of aortic stenosis suggest that in inoperable patients with symptomatic aortic stenosis, TAVI is superior to standard medical treatment. In the high surgical risk cohort, TAVI was comparable to sAVR. Our studies show that patients undergoing aortic root replacement and valve-sparing aortic root reconstruction in Australia have outcomes on par with international institutions. Perioperative mortality, stroke and long term survival is good, especially in the elective setting. In summary, this dissertation has provided a better understanding regarding complex and high risk cardiac surgeries, especially in Australia. The dissertation has established feasibility of such procedures in the elderly and high risk patients and highlights the excellent outcomes that are being achieved with increasing experience.