Secondary Prevention Therapy for Postoperative Myocardial Injury After Noncardiac Surgery (SPECTRE trial)

BACKGROUND: Postoperative myocardial injury (PMI) is defined as a cardiac troponin elevation after noncardiac surgery, and has been described as “common, silent and deadly”. The incidence of PMI is approximately 20% amongst individuals undergoing elective surgery, and approaches 30% amongst those undergoing emergency surgery. More than 90% of PMI is clinically silent, and it is associated with substantial morbidity and mortality at 30 days and 1 year after surgery. Current cardiac society guidelines for PMI recommend secondary prevention therapy for coronary artery disease (CAD), the rationale being that atherosclerotic CAD is the presumed aetiology of PMI in the majority of cases. An important limitation of this recommendation is that it is based on clinical practice guidelines for myocardial injury and infarction in non-surgical patients. Therefore, the uptake of these guidelines globally has been poor, due to uncertainty regarding the efficacy of such interventions amongst surgical patients. OBJECTIVES: 1. To evaluate the feasibility of recruitment, retention and protocol adherence of study participants and 2. To investigate whether initiation or intensification of secondary prevention therapy after PMI is associated with reduced 30-day MI, 1-year disability and 1-year cardiovascular events and mortality. The results of this feasibility study will inform the design of a larger, future multi-centre trial. METHODS: Prospective, single-centre, feasibility RCT. Individuals aged 65 years and over, who have experienced PMI will be eligible. Recruited participants will be randomised to control (standard care) or intervention (secondary prevention therapy). Standard care will consist of the current Royal Melbourne Hospital protocol for managing troponin elevations. Intervention will consist of initiation or intensification of guideline-recommended secondary prevention “bundle”, comprising the following: i) Lifestyle interventions counselling; ii) Pharmacotherapy; iii) Aggressive risk factor modification and iv) Education package for the participant and primary care physician, regarding the diagnosis of PMI, future cardiovascular risk, and advice for lifestyle interventions, pharmacotherapy and risk factor modification. LIKELY BENEFITS AND FURTHER IMPACT OF RESEARCH: Patients experiencing PMI are at significant risk of acute coronary syndromes and cardiovascular death within the first year. Therefore, there is an urgent need for high-quality data regarding effective treatment following PMI, to improve short- and long-term outcomes for surgical patients. This novel study will provide useful data on the feasibility and effectiveness of delivering lifestyle interventions, pharmacotherapy and risk factor modification as an intervention “bundle”. This will be expected to improve survival and quality of life in older surgical patients. HONOURS STUDENT THESIS: This nested study will evaluate the relationship between brain natriuretic peptide (BNP) and postoperative outcomes (myocardial infarction, cardiovascular complications, death) following treatment for PMI. Specifically, the study will examine whether individuals with an elevated postoperative BNP derive greater benefit from secondary prevention therapy for PMI.