Myocardial perfusion imaging failed to improve patient risk classification compared with the revised cardiac risk index for early cardiac complications after major non-cardiac surgery.

BACKGROUND: Myocardial perfusion imaging (MPI) is frequently used for cardiac risk assessment before major non-cardiac surgery, but its ability to improve patient risk classification beyond simple clinical assessment is unknown. AIM: To explore the prognostic utility of MPI above a simple clinical risk calculator, the revised cardiac risk index (RCRI). METHODS: A retrospective cohort study of at-risk patients who underwent MPI before major non-cardiac surgery in a tertiary hospital was conducted. Major adverse cardiac events (MACE) was defined as any myocardial infarction, acute pulmonary oedema, ventricular arrhythmia or cardiac death within 30 days of surgery. We analysed the predictive value of MPI for MACE using multivariable logistic regression and categorical net reclassification index. RESULTS: MACE occurred in 47 (7.4%) cases from 635 surgical procedures in 629 patients. MPI-identified medium or large-sized reversible perfusion defects (P = 0.02; odds ratio 2.9; 95% confidence interval 1.1-7.1) and RCRI score two or more (P = 0.03; odds ratio 2.3; 95% confidence interval 1.1-4.8) were significantly associated with MACE after adjusting for age, coronary revascularisation, surgical priority, need for general anaesthesia, left ventricular ejection fraction (LVEF) and fixed perfusion defects. MPI risk factors (LVEF, reversible perfusion and fixed perfusion defects) did not improve risk classification above baseline risk factors (age, RCRI and surgical priority). CONCLUSION: MPI risk factors are weak predictors for early cardiac complications after major non-cardiac surgery and failed to improve patient risk classification beyond essential assessment using age, RCRI and surgical priority. Clinicians should consider alternative risk assessment strategies because of MPI's poor prognostic utility and its associated time and financial costs.

Cardiac risk assessment with the Revised Cardiac Risk Index index before elective non-cardiac surgery: A retrospective audit from an Australian tertiary hospital.

Clinicians assessing cardiac risk as part of a comprehensive consultation before surgery can use an expanding set of tools, including predictive risk calculators, cardiac stress tests and measuring serum natriuretic peptides. The optimal assessment strategy is unclear, with conflicting international guidelines. We investigated the prognostic accuracy of the Revised Cardiac Risk Index for risk stratification and cardiac outcomes in patients undergoing elective non-cardiac surgery in a contemporary Australian cohort.We audited the records for 1465 consecutive patients 45 years and older presenting to the perioperative clinic for elective non-cardiac surgery in our tertiary hospital. We calculated individual Revised Cardiac Risk Index scores and documented any use of preoperative cardiac tests. The primary outcome was any major adverse cardiac events within 30 days of surgery, including myocardial infarction, pulmonary oedema, complete heart block or cardiac death.Myocardial perfusion imaging was the most common preoperative stress test (4.2%, 61/1465). There was no routine investigation of natriuretic peptide levels for cardiac risk assessment before surgery. Major adverse cardiac events occurred in 1.3% (18/1366) of patients who had surgery. The Revised Cardiac Risk Index score had modest prognostic accuracy for major cardiac complications, area under receiver operator curve 0.73, 95% confidence interval 0.60 to 0.86. Stratifying major adverse cardiac events by the Revised Cardiac Risk Index scores 0, 1, 2 and 3 or greater corresponded to event rates of 0.6% (4/683), 0.8% (4/488), 4.1% (6/145) and 8.0% (4/50), respectively.The Revised Cardiac Risk Index had only modest predictive value in our single-centre experience. Patients with a revised cardiac risk index score of 2 or more had an elevated risk of early cardiac complications after elective non-cardiac surgery.

High-flow nasal cannula versus standard oxygen therapy assisting sedation during endoscopic retrograde cholangiopancreatography in high risk cases (OTHER): study protocol of a randomised multicentric trial.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is an increasingly common intervention in the treatment of pancreaticobiliary disorders. Patients are often elderly with complex co-morbidities. While monitored anaesthesia care with sedation is commonly used for most cases, few would require general anaesthesia with an endotracheal tube. Both low-flow and high-flow nasal cannulas (HFNC) are established ways of delivering supplemental oxygen, but it is unclear whether one technique is better than the other. HFNC seems a promising tool for advanced procedures but evidence to support its application in high-risk ERCP cases is limited. The rate of oxygen desaturation during endoscopy has been reported to be as high as 11%-50% and the method of oxygen delivery for ERCP merits further study. METHODS/DESIGN: This is a prospective, randomised, multicentre trial comparing the efficacy of oxygen supplementation through HFNC versus low-flow nasal cannula during ERCP, in a cohort of patients at risk of adverse respiratory events. A total of 132 patients will be recruited across three sites and randomly assigned to either the low-flow or the HFNC group. The primary outcome is the proportion of patients experiencing hypoxia, defined by any event of SpO2 < 90%. The secondary outcomes include parameters centred on oxygenation, requirement of airway manoeuvres, successful completion of procedure, perioperative complications, patient satisfaction and cost analysis of the consumables. An intention-to-treat principle will be applied while analysing. DISCUSSION: The demand for ERCPs is likely to increase in the future with the aging population. Our study results may lead to improved outcomes and reduce airway-related complications in patients undergoing ERCPs. The results will be presented at national and international meetings and published in peer-reviewed journals. TRIAL REGISTRATION: www.ANZCTR.org.au, CTRN12619000397112. Registered on 12 March 2019.