Minor myocardial damage and prognosis: are spontaneous and percutaneous coronary intervention-related events different?

BACKGROUND: The relevance of the adverse prognostic implications of CK-MB elevation after percutaneous coronary intervention (PCI) remains controversial. Therefore, we compared the relationship between the level of postprocedural CK-MB elevation and 6-month mortality in patients undergoing PCI with the relationship between the level of spontaneous, non-PCI-related CK-MB elevation and 6-month mortality in patients with acute coronary syndromes (ACS) treated medically. METHODS AND RESULTS: In the PURSUIT trial, 5583 of 9461 patients who presented with a non-ST-elevation ACS did not undergo PCI or CABG and had at least 1 CK-MB sample collected during index-hospitalization. There was a gradual increase in 6-month mortality with higher CK-MB levels: 4.1%, 8.6%, 9.0%, 14.3%, 15.5% for CK-MB ratios 0 to 1, >1 to 3, >3 to 5, >5 to 10, and >10 times the upper limit of normal. A combined analysis in 8838 patients undergoing PCI in 5 large, clinical trials revealed a proportional relationship between postprocedural CK-MB levels (1 to 3, >3 to 5, >5 to 10, and >10, the risk of death was 1.3%, 2.0%, 2.3%, 4.3%, and 7.4%, respectively. The absolute mortality rates were lower after procedure-related infarcts compared with spontaneous infarcts. Yet, the relative increase in 6-month mortality with each increase in peak CK-MB level was similar for PCI-related myocardial necrosis and spontaneous myocardial necrosis, as all tests for heterogeneity of the odds ratios were nonsignificant. CONCLUSIONS: The present analysis indicates that the adverse prognostic implications of periprocedural myocardial necrosis should be considered similar to the adverse consequences of spontaneous myocardial necrosis.

Reducing the costs of phase III cardiovascular clinical trials.

BACKGROUND: The pharmaceutical industry spends approximately 26.4 billion dollars annually for research and development (4.1 billion dollars in cardiovascular products). We compared pharmaceutical companies' planned resource use and costs in Phase III cardiovascular trials and identified cost-saving strategies. METHODS AND RESULTS: We developed 2 case scenarios (a 17,000-patient, open-label acute coronary syndromes [ACS] trial and a 14,500-patient, double-blind congestive heart failure [CHF]) trial and surveyed 6 pharmaceutical experts about expected resources (e.g., number of sites, case report form [CRF] pages, and monitoring visits) needed for the trials. Using a validated model, we estimated costs under each expert's assumptions. ACS trial costs averaged 83 million dollars (median, 67 million dollars; range, 57 dollars to 158 million dollars) and 142 million dollars (median, 135 million dollars; range, 102 dollars to 207 million dollars) for the CHF trial. Site-related expenses (site management and payments) were >65% of total costs for both trials. In sensitivity analyses, total costs were reduced >40% by simultaneously reducing CRF pages, monitoring visits, and site-payment amounts but maintaining the numbers of patients and sites. CONCLUSIONS: With a set number of sites and patients, the most efficient way to reduce trial costs and still meet the trial's scientific objectives is to reduce management complexity. Modest changes in management parameters release significant monies to answer more research questions.

Systematic adjudication of myocardial infarction end-points in an international clinical trial.

BACKGROUND: Clinical events committees (CEC) are used routinely to adjudicate suspected end-points in cardiovascular trials, but little information has been published about the various processes used. We reviewed results of the CEC process used to identify and adjudicate suspected end-point (post-enrolment) myocardial infarction (MI) in the large Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin (Eptifibatide) Therapy (PURSUIT) trial. METHODS: The PURSUIT trial randomised 10,948 patients with acute coronary syndromes to receive eptifibatide or placebo. A central adjudication process was established prospectively to identify all suspected MIs and adjudicate events based on protocol definitions of MI. Suspected MIs were identified by systematic review of data collection forms, cardiac enzyme results, and electrocardiograms. Two physicians independently reviewed all suspected events. If they disagreed whether a MI had occurred, a committee of cardiologists adjudicated the case. RESULTS: The CEC identified 5005 patients with suspected infarction (46%), of which 1415 (28%) were adjudicated as end-point infarctions. As expected, the process identified more end-point events than did the site investigators. Absolute and relative treatment effects of eptifibatide were smaller when using CEC-determined MI rates rather than site investigator-determined rates. The site-investigator reporting of MI and the CEC assessment of MI disagreed in 20% of the cases reviewed by the CEC. CONCLUSIONS: End-point adjudication by a CEC is important, to provide standardised, systematic, independent, and unbiased assessment of end-points, particularly in trials that span geographic regions and clinical practice settings. Understanding the CEC process used is important in the interpretation of trial results and event rates.

Disagreements between central clinical events committee and site investigator assessments of myocardial infarction endpoints in an international clinical trial: review of the PURSUIT study.

BACKGROUND: Limited information has been published regarding how specific processes for event adjudication can affect event rates in trials. We reviewed nonfatal myocardial infarctions (MIs) reported by site investigators in the international Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin (Eptifibatide) Therapy (PURSUIT) trial and those adjudicated by a central clinical events committee (CEC) to determine the reasons for differences in event rates. METHODS: The PURSUIT trial randomised 10,948 patients with acute coronary syndromes to receive eptifibatide or placebo. The primary end-point was death or post-enrolment MI at 30 days as assessed by the CEC; this end-point was also constructed using site-reported events. The CEC identified suspected MIs by systematic review of clinical, cardiac enzyme, and electrocardiographic data. RESULTS: The CEC identified 5005 (46%) suspected events, of which 1415 (28%) were adjudicated as MI. The site investigator and CEC assessments of whether a MI had occurred disagreed in 983 (20%) of the 5005 patients with suspected MI, mostly reflecting site misclassification of post-enrolment MIs (as enrolment MIs) or underreported periprocedural MIs. Patients for whom the CEC and site investigator agreed that no end-point MI had occurred had the lowest mortality at 30 days and between 30 days and 6 months, and those with agreement that a MI had occurred had the highest mortality. CONCLUSION: CEC adjudication provides a standard, systematic, independent, and unbiased assessment of end-points, particularly for trials that span geographic regions and clinical practice settings. Understanding the review process and reasons for disagreement between CEC and site investigator assessments of MI is important to design future trials and interpret event rates between trials.