Central Adjudication Identified Additional and Prognostically Important Myocardial Infarctions in Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND

In the CHAMPION PHOENIX trial, cangrelor reduced the primary composite end point of death, myocardial infarction (MI), ischemia-driven revascularization, or stent thrombosis at 48 hours. This study aimed to explore the impact of event adjudication and the prognostic importance of MI reported by a clinical events committee (CEC) or site investigators (SIs).

METHODS AND RESULTS

Data from the CHAMPION PHOENIX trial of patients undergoing elective or nonelective percutaneous coronary intervention were analyzed. A CEC systematically identified and adjudicated MI using predefined criteria, a computer algorithm to identify suspected events, and semilogarithmic plots to review biomarker changes. Thirty-day death was modeled using baseline characteristics. Of 10 942 patients, 462 (4.2%) patients had at least 1 MI by 48 hours identified by the CEC (207 [3.8%] cangrelor; 255 [4.7%] clopidogrel; odds ratio [OR] 0.80; 95% CI, 0.67-0.97; P=0.022), and 143 patients had at least 1 MI by 48 hours reported by the SI (60 [1.1%] cangrelor; 83 [1.5%] clopidogrel; OR, 0.72; 95% CI, 0.52-1.01; P=0.053). Of the 462 MIs identified by the CEC, 92 (20%) were reported by SI, and 370 (80%) were not. Of the 143 MI reported by the SI, 51 (36%) were not confirmed by CEC. All categories were associated with an increased adjusted risk for 30-day death (CEC: OR, 5.35; 95% CI, 2.56-11.2; P<0.001; SI: 9.08 [4.01-20.5]; P<0.001; CEC and SI: 10.9 [3.23-36.6]; P<0.001; CEC but not SI: 4.69 [1.94-11.3]; P<0.001; SI but not CEC: 15.4 [5.26-44.9]; P<0.001).

CONCLUSIONS

In patients undergoing percutaneous coronary intervention, CEC procedures identified 3 times as many MIs as the SI reported. Compared with clopidogrel, cangrelor significantly reduced MIs identified by the CEC with a qualitatively similar relative risk reduction in MIs reported by the SI. MIs identified by CEC or reported by SI were independently associated with worse 30-day death. Central adjudication identified additional, prognostically important events.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01156571.

A model for predicting emergency physician opinion of electrocardiogram tracing data quality

BACKGROUND

Limited work has established an objective measure of ECG quality that correlates with physician opinion of the study. We seek to establish a threshold of acceptable ECG data quality for the purpose of ruling out STEMI derived from emergency physician opinion.

METHODS

A panel of three emergency physicians rated 240 12-Lead ECGs as being acceptable or unacceptable data quality. Each lead of the ECG had the following measurements recorded: baseline wander, QRS signal amplitude, and artifact amplitude. A lasso regression technique was used to create the model.

RESULTS

The area under the curve for the model using all 36 elements is 1.0, indicating a perfect fit. A simplified model using 22 terms has an area under the curve of 0.994.

CONCLUSIONS

This study demonstrated that emergency physician opinion of ECG quality for the purpose of ruling out STEMI can be predicted through a regression model.

Lack of Concordance Between Local Investigators, Angiographic Core Laboratory, and Clinical Event Committee in the Assessment of Stent Thrombosis: Results From the TRACER Angiographic Substudy

BACKGROUND

Stent thrombosis (ST) is an important end point in cardiovascular clinical trials. Adjudication is traditionally based on clinical event committee (CEC) review of case report forms and source documentation rather than angiograms. However, the degree to which this method of adjudication is concordant with the review of independent angiographic core laboratories (ACLs) has not been studied. This report represents the first assessment of variability between local investigators (LIs), a CEC, and an ACL.

METHODS AND RESULTS

Serial angiograms of 329 patients with acute coronary syndrome without ST-segment-elevation who underwent percutaneous coronary intervention at entry in the Trial to Assess the Effects of Vorapaxar in Preventing Heart Attack and Stroke in Particpants With Acute Coronary Syndrome (TRACER) and who met criteria for possible ST subsequent to the index event were reviewed by an ACL. The ACL was blinded to the assessment by both LIs and the CEC regarding the presence or absence of ST. CEC adjudication was based on Academic Research Consortium definitions of ST, using case report form data and source documents, including catheterization laboratory reports. The ACL, CEC, and LIs agreed on the presence or absence of ST in 52.9% events (κ=0.32; 95% confidence interval, 0.26-0.39). The ACL and CEC agreed on 82.7% of events (κ=0.57; 95% confidence interval, 0.47-0.67); the ACL and LIs agreed on 61.1% of events (κ=0.25; 95% confidence interval, 0.16-0.34); and the CEC and LIs agreed on 62% of events (κ=0.28; 95% confidence interval, 0.21-0.36).

CONCLUSIONS

ST reporting by an ACL, a CEC, and LIs is discordant. The assessment of ST is more often detected by direct review of angiograms by an ACL.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00527943.

State-of-the-Art Evaluation of Emergency Department Patients Presenting With Potential Acute Coronary Syndromes

It is well established that clinicians cannot use clinical judgment alone to determine whether an individual patient who presents to the emergency department has an acute coronary syndrome. The history and physical examination do not distinguish sufficiently between the many conditions that can cause acute chest pain syndromes. Cardiac risk factors do not have sufficient discriminatory ability in symptomatic patients presenting to the emergency department. Most patients with non-ST-segment-elevation myocardial infarction do not present with electrocardiographic evidence of active ischemia. The improvement in cardiac troponin assays, especially in conjunction with well-validated clinical decision algorithms, now enables the clinician to rapidly exclude myocardial infarction. In patients in whom unstable angina remains a concern or there is a desire to evaluate for underlying coronary artery disease, coronary computed tomography angiography can be used in the emergency department. Once a process that took ≥24 hours, computed tomography angiography now can rapidly exclude myocardial infarction and coronary artery disease in patients in the emergency department.

Agreement between cardiologists and fellows in interpretation of ischemic electrocardiographic changes in acute myocardial infarction

BACKGROUND

Time from symptom onset may not be the best indicator for choosing reperfusion therapy for patients presenting with acute ST-elevation myocardial infarction (STEMI); consequently ECG-based methods have been developed.

METHODS

This study evaluated the inter-observer agreement between experienced cardiologists and junior doctors in identifying the ECG findings of the pre-infarction syndrome (PIS) and evolving myocardial infarction (EMI). The ECGs of 353 STEMI patients were independently analyzed by two cardiologists, one fellow in cardiology, one fellow in internal medicine and a medical student. The last two were given a half-hour introduction of the PIS/EMI-algorithm.

RESULTS

The inter-observer reliability between all the investigators was found to be good according to kappa statistics (κ 0.632-0.790) for the whole study population. When divided into different subgroups, the inter-observer agreements were from good to very good between the cardiologists and the fellow in cardiology (κ 0.652 -0.813) and from moderate to good (κ 0.464-0.784) between the fellow in internal medicine, medical student and the others.

CONCLUSIONS

The PIS and EMI ECG patterns are reliably identified by experienced cardiologists and can be easily adopted by junior doctors.

Agreement in electrocardiogram interpretation in patients with septic shock

OBJECTIVE

The reliability of electrocardiogram interpretation to diagnose myocardial ischemia in critically ill patients is unclear. In adults with septic shock, we assessed intra- and inter-rater agreement of electrocardiogram interpretation, and the effect of knowledge of troponin values on these interpretations.

DESIGN

Prospective substudy of a randomized trial of vasopressin vs. norepinephrine in septic shock.

SETTING

Nine Canadian intensive care units.

PATIENTS

Adults with septic shock requiring at least 5 μg/min of norepinephrine for 6 hrs.

INTERVENTIONS

Twelve-lead electrocardiograms were recorded before study drug, and 6 hrs, 2 days, and 4 days after study drug initiation.

MEASUREMENTS

Two physician readers, blinded to patient data and group, independently interpreted electrocardiograms on three occasions (first two readings were blinded to patient data; third reading was unblinded to troponin). To calibrate and refine definitions, both readers initially reviewed 25 trial electrocardiograms representing normal to abnormal. Cohen's Kappa and the φ statistic were used to analyze intra- and inter-rater agreement.

RESULTS

One hundred twenty-one patients (62.2 ± 16.5 yrs, Acute Physiology and Chronic Health Evaluation II 28.6 ± 7.7) had 373 electrocardiograms. Blinded to troponin, readers 1 and 2 interpreted 46.4% and 30.0% of electrocardiograms as normal, and 15.3% and 12.3% as ischemic, respectively. Intrarater agreement was moderate for overall ischemia (κ 0.54 and 0.58), moderate/good for "normal" (κ 0.69 and 0.55), fair to good for specific signs of ischemia (ST elevation, T inversion, and Q waves, reader 1 κ 0.40 to 0.69; reader 2 κ 0.56 to 0.70); and good/very good for atrial arrhythmias (κ 0.84 and 0.79) and bundle branch block (κ 0.88 and 0.79). Inter-rater agreement was fair for ischemia (κ 0.29), moderate for ST elevation (κ 0.48), T inversion (κ 0.52), and Q waves (κ 0.44), good for bundle branch block (κ 0.78), and very good for atrial arrhythmias (κ 0.83). Inter-rater agreement for ischemia improved from fair to moderate (κ 0.52, p = .028) when unblinded to troponin.

CONCLUSIONS

In patients with septic shock, inter-rater agreement of electrocardiogram interpretation for myocardial ischemia was fair, and improved with troponin knowledge.