Outcomes of Redo Valve Surgery in Indigenous Australians

Abstract

Background: Rheumatic heart disease often leads to valve surgery at a young age in our Indigenous population. Anticoagulation can be problematic and therefore repeat surgery to replace degenerated bioprosthetic valves is common. We sought to examine outcomes following redo valve surgery in this population.

Methods: Data from our institutional database was reviewed from 1992 to 2017. During this period, 82 redo valve surgeries were performed in 73 patients identifying as Aboriginal and Torres Strait Islander. We compared this study group to Indigenous patients undergoing primary valve surgery (n=389) and non-Indigenous patients undergoing redo valve surgery (n=154).

Results: Redo patients had a median age of 29.5 years (IQR 24, 44), 59% were female, and they had significant comorbidities. The 30-day mortality in this cohort was 6% (EuroSCORE II 3.57), and they had significant morbidity. The median time to repeat surgery in those who had previous mitral valve surgery was 6.3 years, with no difference between mitral valve repair or replacement at the index procedure. Compared to non-Indigenous patients undergoing redo valve surgery, the Indigenous patients were significantly younger with higher left ventricular function but a greater proportion of pulmonary hypertension. There were no significant differences in short-term outcomes. Compared to Indigenous patients undergoing primary valve surgery, the Indigenous redo patients were significantly younger with more co-morbidities. There was no difference in 30-day mortality, but the redo patients did have significantly greater resource utilisation (increased hospital and intensive care unit (ICU) lengths of stay, ventilation and blood transfusion) and poorer long-term survival.

Conclusions: Indigenous patients presenting for redo valve surgery represent a complex and comorbid group of patients, with outcomes worse than expected in a young population, albeit comparable within study groups. Time from original surgery was short at 6 years, and thus a strategy must be in place in terms of planning future surgeries in this cohort of predominantly young rheumatic heart disease patients.

Keywords: Aboriginal; Cardiac surgery; Rheumatic heart disease.