The impact of high-sensitivity troponin implementation on hospital operations and patient outcomes in 3 tertiary care centers.

OBJECTIVE: High-sensitivity troponin T (hs-TnT) assays detect myocardial injury sooner, possibly improving throughput times for emergency department (ED) assessment of suspected acute myocardial infarction (AMI). This study evaluates the influence of hs-TnT implementation on ED length of stay (LOS), consultations and admissions, as well as ED revisits with cardiology admissions for patients undergoing testing for suspected AMI. METHODS: This control pre-post design analysis included patients evaluated using hs-TnT or conventional troponin T. Data were collected from 3 ED databases for patients who had a troponin assay for suspected AMI for the periods February 12, 2011-April 22, 2011 (Ctrl); November 20, 2011-January 28, 2012 (Pre); and February 12, 2012-April 21, 2012 (Post). The primary outcome was ED LOS; secondary outcomes included the proportions of patients who received ED cardiology consultations, patients who were admitted to hospital, and discharged patients who revisited the ED within 30 days. RESULTS: Data were analyzed from 6650 (Ctrl), 6866 (Pre), and 5754 (Post) patients. Median ED LOS decreased following hs-TnT implementation (6.60 hours in Ctrl and Pre vs 6.10 hours in Post, P < .001). There was no change in cardiology consultations or admissions following hs-TnT implementation. Fewer ED revisits occurred within 30 days in Post (16.0% Ctrl, 16.5% Pre vs 14.9% Post; P < .01). These results were preserved after adjusting for age and Canadian Triage Acuity Score. CONCLUSIONS: This hs-TnT implementation strategy, using an equivalent cutoff for the conventional troponin T and hs-TnT assays, decreased ED LOS for patients with suspected AMI and did not increase cardiology resource utilization or ED revisits.

The Enhancing Secondary Prevention in Coronary Artery Disease trial.

BACKGROUND: Proven efficacious therapies are sometimes underused in patients with chronic cardiac conditions, resulting in suboptimal outcomes. We evaluated whether evidence summaries, which were either unsigned or signed by local opinion leaders, improved the quality of secondary prevention care delivered by primary care physicians of patients with coronary artery disease. METHODS: We performed a randomized trial, clustered at the level of the primary care physician, with 3 study arms: control, unsigned statements or opinion leader statements. The statements were faxed to primary care physicians of adults with coronary artery disease at the time of elective cardiac catheterization. The primary outcome was improvement in statin management (initiation or dose increase) 6 months after catheterization. RESULTS: We enrolled 480 adults from 252 practices. Although statin use was high at baseline (n=316 [66%]), most patients were taking a low dose (mean 32% of the guideline-recommended dose), and their low-density lipoprotein (LDL) cholesterol levels were elevated (mean 3.09 mmol/L). Six months after catheterization, statin management had improved in 79 of 157 patients (50%) in the control arm, 85 of 158 (54%) patients in the unsigned statement group (adjusted odds ratio [OR] 1.18, 95% CI 0.71-1.94, p=0.52) and 99 of 165 (60%) patients in the opinion leader statement group (adjusted OR 1.51, 95% CI 0.94-2.42, p=0.09). The mean fasting LDL cholesterol levels after 6 months were similar in all 3 study arms: 2.35 (standard deviation [SD] 0.86) mmol/L in the control arm compared with 2.24 (SD 0.73) among those in the opinion leader group (p=0.48) and 2.19 (SD 0.68) in the unsigned statement group (p=0.32). INTERPRETATION: Faxed evidence reminders for primary care physicians, even when endorsed by local opinion leaders, were insufficient to optimize the quality of care for adults with coronary artery disease. ClinicalTrials.gov trial register no. NCT00175240.

Noninvasive risk assessment early after a myocardial infarction the REFINE study.

OBJECTIVES: This study sought to determine whether combined assessment of autonomic tone plus cardiac electrical substrate identifies most patients at risk of serious events after myocardial infarction (MI) and to compare assessment at 2 to 4 weeks versus 10 to 14 weeks after MI. BACKGROUND: Methods to identify most patients at risk of serious events after MI are required. METHODS: Patients (n = 322) with an ejection fraction (EF) <0.50 in the initial week after MI were followed up for a median of 47 months. Serial assessment of autonomic tone, including heart rate turbulence (HRT), electrical substrate, including T-wave alternans (TWA), and EF was performed, interpreted blinded, and categorized using pre-specified cut-points where available. The primary outcome was cardiac death or resuscitated cardiac arrest. All-cause mortality and fatal or nonfatal cardiac arrest were secondary outcomes. RESULTS: Mean EF significantly increased over the initial 8 weeks after MI. Testing 2 to 4 weeks after MI did not reliably identify patients at risk, whereas testing at 10 to 14 weeks did. The 20% of patients with impaired HRT, abnormal exercise TWA, and an EF <0.50 beyond 8 weeks post-MI had a 5.2 (95% confidence interval [CI] 2.4 to 11.3, p < 0.001) higher adjusted risk of the primary outcome. This combination identified 52% of those at risk, with good positive (23%; 95% CI 17% to 26%) and negative (95%; 95% CI 93% to 97%) accuracy. Similar results were observed for the secondary outcomes. CONCLUSIONS: Impaired HRT, abnormal TWA, and an EF <0.50 beyond 8 weeks after MI reliably identify patients at risk of serious events. (Assessment of Noninvasive Methods to Identify Patients at Risk of Serious Arrhythmias After a Heart Attack; http://www.clinicaltrials.gov/ct/show/NCT00399503?order=1; NCT00399503).

Expedited transfer for primary percutaneous coronary intervention: a program evaluation.

BACKGROUND: A shorter time from symptom onset to reperfusion is associated with improved outcomes for patients with ST-segment elevation myocardial infarction (MI). Primary percutaneous coronary intervention is a favourable method of reperfusion if performed effectively and expeditiously. We sought to evaluate the impact of an expedited pre-hospital diagnosis and transfer pathway developed by a multidisciplinary team on the door-to-balloon time in a large urban community. METHODS: We included all patients with ST-segment elevation MI who presented within 12 hours after symptom onset and who sought medical attention through Emergency Medical Services within the boundaries of the city of Calgary in the 16 months following the introduction of the pathway in June 2004. The primary aim was to determine the proportion of patients who received percutaneous coronary intervention within the recommended door-to-balloon time of 90 minutes. RESULTS: The 358 patients (268 men) in the study cohort had a mean age of 63.2 (standard deviation 12.7) years; 140 (39.1%) had an anterior MI; and 23 (6.4%) had cardiogenic shock. The introduction of the pathway resulted in a median door-to-balloon time of 62 (interquartile range 45-84) minutes. A door-to-balloon time within 60 minutes and within the currently recommended 90 minutes was achieved in 48.9% and 78.8% of the patients respectively. The in-hospital and 30-day mortality rates were both 3.1%. INTERPRETATION: In a community with multiple regional hospitals and a single facility for percutaneous coronary intervention, the implementation of a multidisciplinary pre-hospital diagnosis and transfer pathway was feasible and resulted in most patients in the study cohort receiving primary percutaneous coronary intervention within the recommended door-to-balloon time of 90 minutes.

A randomized trial to assess the impact of opinion leader endorsed evidence summaries on the use of secondary prevention strategies in patients with coronary artery disease: the ESP-CAD trial protocol [NCT00175240].

BACKGROUND: Although numerous therapies have been shown to be beneficial in the prevention of myocardial infarction and/or death in patients with coronary disease, these therapies are under-used and this gap contributes to sub-optimal patient outcomes. To increase the uptake of proven efficacious therapies in patients with coronary disease, we designed a multifaceted quality improvement intervention employing patient-specific reminders delivered at the point-of-care, with one-page treatment guidelines endorsed by local opinion leaders ("Local Opinion Leader Statement"). This trial is designed to evaluate the impact of these Local Opinion Leader Statements on the practices of primary care physicians caring for patients with coronary disease. In order to isolate the effects of the messenger (the local opinion leader) from the message, we will also test an identical quality improvement intervention that is not signed by a local opinion leader ("Unsigned Evidence Statement") in this trial. METHODS: Randomized trial testing three different interventions in patients with coronary disease: (1) usual care versus (2) Local Opinion Leader Statement versus (3) Unsigned Evidence Statement. Patients diagnosed with coronary artery disease after cardiac catheterization (but without acute coronary syndromes) will be randomly allocated to one of the three interventions by cluster randomization (at the level of their primary care physician), if they are not on optimal statin therapy at baseline. The primary outcome is the proportion of patients demonstrating improvement in their statin management in the first six months post-catheterization. Secondary outcomes include examinations of the use of ACE inhibitors, anti-platelet agents, beta-blockers, non-statin lipid lowering drugs, and provision of smoking cessation advice in the first six months post-catheterization in the three treatment arms. Although randomization will be clustered at the level of the primary care physician, the design effect is anticipated to be negligible and the unit of analysis will be the patient. DISCUSSION: If either the Local Opinion Leader Statement or the Unsigned Evidence Statement improves secondary prevention in patients with coronary disease, they can be easily modified and applied in other communities and for other target conditions.

Validation of dual-chamber pacemaker diagnostic data using dual-channel stored electrograms.

BACKGROUND: Pacemaker diagnostic counters are used to guide device programming and patient management. However, these data are susceptible to inappropriate classification of events. The aim of this multicenter study was to evaluate pacemaker diagnostic data using stored intracardiac electrograms (EGMs). METHODS: The study included 351 patients (191 males, aged 71 +/- 10 years) with standard indications for dual-chamber pacemaker implantation. EGM triggers were atrial tachycardia (AT), ventricular tachycardia (VT), sudden bradycardia response (SBR), and pacemaker-mediated tachycardia (PMT). For this study, the devices could store up to 5 EGMs of 8s each (with marker annotation and onset recording). After 3 months, the EGMs were analyzed and classified as "confirmed" if the EGM validated the trigger and as "false positive" if the EGM showed an event different from the trigger. RESULTS: Of the 1,003 EGMs available, the triggers were AT in 640 EGMs, VT in 76, SBR in 105, and PMT in 178 EGMs. Four EGMs were triggered by magnet application. The trigger was confirmed in 614 EGMs (62%): 62% of AT episodes, 18% of VT episodes, 100% of SBR episodes, and 54% of PMT episodes. In 385 cases (45%), the EGMs revealed false-positive events due to far-field sensing (39%), noise and myopotential sensing (26%), sinus tachycardias (21%), double counting (9%), exit block (4%), and undersensing (1%). CONCLUSION: This large-scale study of stored EGMs revealed their value in validating diagnostic counter data. Therapeutic decisions should not be based on diagnostic counters alone; they should be validated by sophisticated tools like stored EGMs.