Characteristics and short-term prognosis of perioperative myocardial infarction in patients undergoing noncardiac surgery: a cohort study.

BACKGROUND: Each year, millions of patients worldwide have a perioperative myocardial infarction (MI) after noncardiac surgery. OBJECTIVE: To examine the characteristics and short-term outcome of perioperative MI. DESIGN: Cohort study. (ClinicalTrials.gov registration number: NCT00182039) SETTING: 190 centers in 23 countries. PATIENTS: 8351 patients included in the POISE (PeriOperative ISchemic Evaluation) trial. MEASUREMENTS: Four cardiac biomarker or enzyme assays were measured within 3 days of surgery. The definition of perioperative MI included either autopsy findings of acute MI or an elevated level of a cardiac biomarker or enzyme and at least 1 of the following defining features: ischemic symptoms, development of pathologic Q waves, ischemic changes on electrocardiography, coronary artery intervention, or cardiac imaging evidence of MI. RESULTS: Within 30 days of random assignment, 415 patients (5.0%) had a perioperative MI. Most MIs (74.1%) occurred within 48 hours of surgery; 65.3% of patients did not experience ischemic symptoms. The 30-day mortality rate was 11.6% (48 of 415 patients) among patients who had a perioperative MI and 2.2% (178 of 7936 patients) among those who did not (P < 0.001). Among patients with a perioperative MI, mortality rates were elevated and similar between those with (9.7%; adjusted odds ratio, 4.76 [95% CI, 2.68 to 8.43]) and without (12.5%; adjusted odds ratio, 4.00 [CI, 2.65 to 6.06]) ischemic symptoms. LIMITATION: Cardiac markers were measured only until day 3 after surgery, and additional asymptomatic MIs may have been missed. CONCLUSION: Most patients with a perioperative MI will not experience ischemic symptoms. Data suggest that routine monitoring of troponin levels in at-risk patients is needed after surgery to detect most MIs, which have an equally poor prognosis regardless of whether they are symptomatic or asymptomatic.

Characteristics and short-term prognosis of perioperative myocardialinfarction in patients undergoing noncardiac surgery a cohort study

BACKGROUND: Each year, millions of patients worldwide have a perioperative myocardial infarction (MI) after noncardiac surgery.OBJECTIVE: To examine the characteristics and short-term outcome of perioperative MI.DESIGN: Cohort study. (ClinicalTrials.gov registration number: NCT00182039)SETTING: 190 centers in 23 countries.PATIENTS: 8351 patients included in the POISE (PeriOperative ISchemic Evaluation) trial.MEASUREMENTS: Four cardiac biomarker or enzyme assays were measured within 3 days of surgery. The definition of perioperative MI included either autopsy findings of acute MI or an elevated level of a cardiac biomarker or enzyme and at least 1 of the following defining features: ischemic symptoms, development of pathologic Q waves, ischemic changes on electrocardiography, coronary artery intervention, or cardiac imaging evidence of MI.RESULTS: Within 30 days of random assignment, 415 patients (5.0%) had a perioperative MI. Most MIs (74.1%) occurred within 48 hours of surgery; 65.3% of patients did not experience ischemic symptoms. The 30-day mortality rate was 11.6% (48 of 415 patients) among patients who had a perioperative MI and 2.2% (178 of 7936 patients) among those who did not (P < 0.001). Among patients with a perioperative MI, mortality rates were elevated and similar between those with (9.7%; adjusted odds ratio, 4.76 [95% CI, 2.68 to 8.43]) and without (12.5%; adjusted odds ratio, 4.00 [CI, 2.65 to 6.06]) ischemic symptoms.LIMITATION: Cardiac markers were measured only until day 3 after surgery, and additional asymptomatic MIs may have been missed.CONCLUSION: Most patients with a perioperative MI will not experience ischemic symptoms. Data suggest that routine monitoring of troponin levels in at-risk patients is needed after surgery to detect most MIs, which have an equally poor prognosis regardless of whether they are symptomatic or asymptomatic.

Specific barriers to the conduct of randomized trials.

Large randomized trials are required to provide reliable evidence of the typically moderate benefit of most interventions. To be affordable, such trials need to be simple; to be widely applicable, they need to be close to normal clinical practice. However, current regulations and guidelines have hugely increased trial complexity, effectively becoming barriers to their design and conduct. Key barriers include inadequate funding, overly complex regulations producing needlessly complex trial procedures, excessive monitoring, over restrictive interpretation of privacy laws without evidence of subject benefit, and inadequate understanding of methodology. Complex regulations result in multiple ethics approvals for a multi-center study, unnecessary complexity in the study protocol, delays in securing regulatory approval, and cumbersome regulatory procedures, even for drugs widely used in clinical practice. The type of detailed safety monitoring currently needed in trials of new drugs is being applied indiscriminately to all studies including a simpler and basic level of monitoring that constitutes good practice in most trials could be agreed on, with that level being exceeded only in specific instances. More evidence about the pros and cons of alternative approaches to data quality monitoring would help inform this process. Complex procedures in the form of multiple-page consent forms, overzealous monitoring of side effects and adverse events, source data verification, and over-restrictive approaches to protocol amendments, can impede, rather than facilitate, trial objectives. Finally, further education on the nuances and functions of randomisation would facilitate trial conduct, and reduce the need for burdensome complexity. A radical re-evaluation of existing trial guidelines is needed, based on a clear understanding of the important principles of randomized trials, with the objective of eliminating unnecessary documentation and reporting without sacrificing validity or safety. Researchers should encourage public debate about how best to strike the balance between regulation and cost.