Factors associated with door-in to door-out delays among ST-segment elevation myocardial infarction (STEMI) patients transferred for primary percutaneous coronary intervention: a population-based cohort study in Ontario, Canada.

BACKGROUND: Compared to ST-segment elevation myocardial infarction (STEMI) patients who present at centres with catheterization facilities, those transferred for primary percutaneous coronary intervention (PCI) have substantially longer door-in to door-out (DIDO) times, where DIDO is defined as the time interval from arrival at a non-PCI hospital, to transfer to a PCI hospital. We aimed to identify potentially modifiable factors to improve DIDO times in Ontario, Canada and to assess the impact of DIDO times on 30-day mortality. METHODS: A population-based, retrospective cohort study of 966 STEMI patients transferred for primary PCI in Ontario in 2012 was conducted. Baseline factors were examined across timely DIDO status. Multivariate logistic regression was used to examine independent predictors of timely DIDO as well as the association between DIDO times and 30-day mortality. RESULTS: The median DIDO time was 55 min, with 20.1% of patients achieving the recommended DIDO benchmark of ≤30 min. Age (OR> 75 vs 18-55 0.30, 95% CI: 0.16-0.56), symptom-to-first medical contact (FMC) time (OR61-120mins vs < 60mins 0.60, 95% CI: 0.39-0.90; OR>120mins vs < 60mins 0.53, 95% CI:0.35-0.81) and emergency medical services transport with a pre-hospital electrocardiogram (ECG) (OREMS transport + ECG vs self-transport 2.63, 95% CI:1.59-4.35) were the strongest predictors of timely DIDO. Patients with timely ECG were more likely to have recommended DIDO times (33.0% vs 12.3%; P < 0.001). A significantly higher proportion of those who met the DIDO benchmark had timely FMC-to-balloon times (78.7% vs 27.4%; P < 0.001). Compared to patients with DIDO time ≤ 30 min, those with DIDO times > 90 min had significantly higher adjusted 30-day mortality rates (OR 2.82, 95% CI:1.10-7.19). CONCLUSIONS: While benchmark DIDO times were still rarely achieved in the province, we identified several potentially modifiable factors in the STEMI system that might be targeted to improve DIDO times. Our findings that patients who received a pre-hospital ECG were still being transferred to non-PCI capable centres suggest strategies addressing this gap may improve patient outcomes.

The Incidence of Major Cardiovascular Events in Immigrants to Ontario, Canada: The CANHEART Immigrant Study.

BACKGROUND: Immigrants from ethnic minority groups represent an increasing proportion of the population in many high-income countries but little is known about the causes and amount of variation between various immigrant groups in the incidence of major cardiovascular events. METHODS AND RESULTS: We conducted the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) Immigrant study, a big data initiative, linking information from Citizenship and Immigration Canada's Permanent Resident database to nine population-based health databases. A cohort of 824 662 first-generation immigrants aged 30 to 74 as of January 2002 from eight major ethnic groups and 201 countries of birth who immigrated to Ontario, Canada between 1985 and 2000 were compared to a reference group of 5.2 million long-term residents. The overall 10-year age-standardized incidence of major cardiovascular events was 30% lower among immigrants compared with long-term residents. East Asian immigrants (predominantly ethnic Chinese) had the lowest incidence overall (2.4 in males, 1.1 in females per 1000 person-years) but this increased with greater duration of stay in Canada. South Asian immigrants, including those born in Guyana had the highest event rates (8.9 in males, 3.6 in females per 1000 person-years), along with immigrants born in Iraq and Afghanistan. Adjustment for traditional risk factors reduced but did not eliminate differences in cardiovascular risk between various ethnic groups and long-term residents. CONCLUSIONS: Striking differences in the incidence of cardiovascular events exist among immigrants to Canada from different ethnic backgrounds. Traditional risk factors explain part but not all of these differences.

Association between publication of appropriate use criteria and the temporal trends in diagnostic angiography in stable coronary artery disease: A population-based study.

BACKGROUND: The appropriate use criteria (AUC) were developed to aid clinicians in making clinical decisions regarding coronary angiography. The aim of the present study was to evaluate the association between the publication of the AUC criteria in diagnostic angiography and rates of angiography in Ontario. METHODS: Our cohort consisted of all patients who underwent coronary angiography in Ontario from 1st October 2008 to 31st October 2013 for the indication of suspected stable coronary artery disease. We determined monthly age- and sex-standardized rates of angiography per 100,000 adults. To determine the association between the publication of the AUC for diagnostic angiograms and the rates of angiography, we conducted a time series analysis using an autoregressive integrated moving average model. As a sensitivity analyses, we evaluated the impact of the AUC on the rates of percutaneous coronary intervention (PCI) per 100 angiograms. RESULTS: We included 114,551 angiograms for stable coronary artery disease. In the period prior to the publication of the AUC, the average monthly age- and sex-standardized rate of angiography was 18.7 per 100,000; post-AUC, the average monthly rate decreased to 17.6 per 100,000 adults (P = .037). In contrast, in the 29,358 PCIs included in the analysis, the monthly PCI rates per 100 angiograms were unchanged (25.2 pre-AUC; 26.8 post-AUC; P = .29). In the sensitivity analysis, the rate of appropriate/inappropriate and uncertain indication did not significantly change over the study period. CONCLUSIONS: The publication of the diagnostic angiography AUC criteria was associated with a decrease in the population rates of diagnostic angiography. This suggests that the AUC potentially was associated with an increased threshold to pursue invasive diagnostic testing.

Projected Real-World Effectiveness of Using Aggressive Low-Density Lipoprotein Cholesterol Targets Among Elderly Statin Users Following Acute Coronary Syndromes in Canada.

BACKGROUND: The extent to which outcome benefits may be achieved through the implementation of aggressive low-density lipoprotein (LDL) cholesterol targets in real world settings remains unknown, especially among elderly statin users following acute coronary syndromes. METHODS AND RESULTS: A population-based cohort study consisting of 19 544 post-acute coronary syndrome statin-users aged ≥66 years between January 1, 2017 and March 31, 2014 was used to project the number of adverse outcome events (acute myocardial infarction or death from any cause) that could be prevented if all post-acute coronary syndrome elderly statin users were treated to 1 of 2 LDL cholesterol target levels (≤50 and ≤70 mg/dL). The number of preventable adverse outcomes was estimated by using model-based expected event probabilities as derived from Cox Proportional hazards models. In total, 61.6% and 25.5% of the elderly patients met LDL cholesterol targets of ≤70 and ≤50 mg/dL, respectively, based on current management. No more than 2.3 adverse events per 1000 elderly statin users (95% confidence interval: -0.7 to 5.4, P=0.62) could be prevented over 8.1 years if all patients were to be treated from current LDL cholesterol levels to either of the 2 LDL cholesterol targets of 70 or 50 mg/dL. CONCLUSIONS: The number of acute myocardial infarctions or death that could be prevented through the implementation of LDL cholesterol targets with statins is negligible among an elderly post-acute coronary syndrome population. Such findings may have implications for the applicability of newer agents, such as proprotein convertase subtilisin/kexin type-9- inhibitors.

Comparison of Anatomic and Clinical Outcomes in Patients Undergoing Alternative Initial Noninvasive Testing Strategies for the Diagnosis of Stable Coronary Artery Disease.

BACKGROUND: The optimal initial noninvasive diagnostic testing strategy for stable coronary artery disease (CAD) is unknown. Although American guidelines recommend an exercise stress test as the first-line test, European guidelines suggest that stress imaging (myocardial perfusion imaging or stress echocardiography) or coronary computed tomography angiography may be preferable. Understanding the relationship between the initial strategy and downstream yield of obstructive CAD and major adverse cardiac events may provide insight as to the optimal strategy. METHODS AND RESULTS: We conducted a population-based retrospective cohort study of adults in Ontario, Canada, using health administrative and clinical data. The relationship between the initial testing strategy and obstructive CAD on invasive angiography was examined. Patients were then followed from their angiogram onward to determine whether they developed a composite end point of major adverse cardiac events. After adjusting for covariates, patients with initial myocardial perfusion imaging (odds ratio: 0.92; 95% confidence interval, 0.85, 1.00), coronary computed tomography angiography (odds ratio: 1.51; 95% confidence interval, 0.91, 2.49), or stress echo (odds ratio: 0.95; 95% confidence interval, 0.84, 1.08) did not a have significantly different yield of obstructive CAD compared with those with an initial exercise stress test. Furthermore, there was no significant difference in downstream major adverse cardiac events after invasive angiography among the 4 initial testing strategies after adjusting for clinically relevant covariates. CONCLUSIONS: Our study found no evidence to suggest significant differences in either yield of obstructive CAD or downstream major adverse cardiac events in patients undergoing an initial noninvasive testing strategy with stress or anatomical imaging compared with those undergoing an initial exercise stress test.

Temporal Trends in the Utilization of Noninvasive Diagnostic Tests for Coronary Artery Disease in Ontario Between 2008 and 2014: A Population-Based Study.

The proliferation of cardiac diagnostic tests over the past few decades has received substantial attention from policymakers. However, contemporary population-based temporal trends of the utilization of noninvasive cardiac diagnostic tests for coronary artery disease are not known. Our objective was to examine the temporal trends in the utilization of coronary computed tomography angiography (CCTA), myocardial perfusion imaging (MPI), exercise stress testing (GXT), and stress echocardiography between 2008 and 2014. We performed a population-based repeated cross-sectional study of the adult population of Ontario between January 1, 2008 and December 31, 2014. Annual utilization rates of noninvasive cardiac diagnostic tests were computed. For each cardiac testing modality, a negative binomial regression model was used to assess temporal changes in test utilization. GXT and MPI collectively accounted for 88% of all cardiac noninvasive diagnostic tests throughout our study period. Age- and sex-standardized rates of GXT declined from 26.7/1000 adult population to 21.6/1000 adult population (mean annual reduction of 3.4%; P < 0.001). MPI rates declined from 21.1/1000 adult population to 19.5/1000 adult population (mean annual reduction of 1.3%; P < 0.001). Although utilization rates for both CCTA and stress echocardiography increased over time, the combined rate of all available tests decreased from 50.8/1000 adult population to 49.1/1000 adult population (mean annual reduction of 1.1%; P < 0.001). In conclusion, utilization rates for the most prevalent noninvasive cardiac diagnostic tests-GXT and MPI-declined over our study period. Furthermore, the overall test utilization rate also declined over time. We believe our findings are encouraging from a health policy perspective. Nonetheless, rising utilization rates for CCTA and stress echocardiography will need to be monitored in the future.

The Risk of Ischemic Heart Disease and Stroke Among Immigrant Populations: A Systematic Review.

BACKGROUND: The increasing frequency of global migration to Canada and other high-income countries has highlighted the need for information on the risk of ischemic heart disease (IHD) and stroke among migrant populations. METHODS: Using the MEDLINE and EMBASE databases, we conducted an English-language literature review of articles published from 2000 to 2014 to study patterns in the incidence of IHD or stroke in migrant populations to high-income countries. Our search revealed 17 articles of interest. All studies stratified immigrants according to country or region of birth, except 2 from Canada and 1 from Denmark, in which all immigrant groups were analyzed together. RESULTS: The risk of IHD or stroke varied by country of origin, country of destination, and duration of residence. In our review we found that most migrant groups to Western Europe were at a similar or higher risk of IHD and stroke compared with the host population. Those at a higher risk included many Eastern European, Middle-Eastern, and South Asian immigrants. When duration of residence was considered, it appeared that in most migrants the risk of IHD worsened over time. In contrast, immigrants overall were at lower risk of myocardial infarction and stroke in Ontario compared with long-term residents of Canada. CONCLUSIONS: The risks of IHD and stroke vary widely in immigrant populations in Western Europe. Detailed studies of immigrants to Canada according to country of birth and duration of residence should be undertaken to guide future cardiovascular health promotion initiatives.

Utilization of cardiac computed tomography angiography and outpatient invasive coronary angiography in Ontario, Canada.

BACKGROUND: Cardiac computed tomography angiography (coronary CTA) has emerged as a non-invasive method of diagnosing coronary artery disease. The extent of utilization and uptake of this technology since initiation of its funding by the government of Ontario is unknown. OBJECTIVES: The aim of our study was to examine coronary CTA utilization and the rates of elective invasive coronary angiography and revascularization before and after funding initiation. METHODS: We studied all coronary CTAs performed on adults in Ontario after initiation of funding. We also used an interrupted time series analysis to compare the average monthly rates of invasive angiography and revascularization before and after initiation of funding. RESULTS: There was an initial steep increase in age-and sex-standardized rates of coronary CTA from 5.0 to 11.4/100,000 over the first two quarters after funding initiation. Afterwards, there was a gradual increase in utilization from 11.4 to 17.1/100,000 over two subsequent calendar years. There was a significant reduction in both the mean monthly outpatient invasive coronary angiography (from 20.7 to 19.9 per 100,000 (p = 0.0004)) and revascularization (from 4.9 to 4.4 per 100,000 (p < 0.0001)) rates in the three years following introduction of the coronary CTA billing code as compared to the three prior to its introduction. CONCLUSIONS: Since the introduction of coronary CTA funding in Ontario, there has been a steady and controlled increase in its utilization. The increasing use of coronary CTA was associated with a reduction in both the rates of invasive angiography and revascularization.

The Cardiovascular Health in Ambulatory Care Research Team (CANHEART): using big data to measure and improve cardiovascular health and healthcare services.

BACKGROUND: The CArdiovascular HEalth in Ambulatory care Research Team (CANHEART) is conducting a unique, population-based observational research initiative aimed at measuring and improving cardiovascular health and the quality of ambulatory cardiovascular care provided in Ontario, Canada. A particular focus will be on identifying opportunities to improve the primary and secondary prevention of cardiovascular events in Ontario's diverse multiethnic population. METHODS AND RESULTS: A population-based cohort comprising 9.8 million Ontario adults ≥20 years in 2008 was assembled by linking multiple electronic survey, health administrative, clinical, laboratory, drug, and electronic medical record databases using encoded personal identifiers. The cohort includes ≈9.4 million primary prevention patients and ≈400,000 secondary prevention patients. Follow-up on clinical events is achieved through record linkage to comprehensive hospitalization, emergency department, and vital statistics administrative databases. Profiles of cardiovascular health and preventive care will be developed at the health region level, and the cohort will be used to study the causes of regional variation in the incidence of major cardiovascular events and other important research questions. CONCLUSIONS: Linkage of multiple databases will enable the CANHEART study cohort to serve as a powerful big data resource for scientific research aimed at improving cardiovascular health and health services delivery. Study findings will be shared with clinicians, policy makers, and the public to facilitate population health interventions and quality improvement initiatives.

Classification of Canadian immigrants into visible minority groups using country of birth and mother tongue.

BACKGROUND: The Permanent Resident Database of Citizenship and Immigration Canada (CIC) contains sociodemographic information on immigrants but lacks ethnic group classifications. To enhance its usability for ethnicityrelated research, we categorized immigrants in the CIC database into one of Canada's official visible minority groups or a white category using their country of birth and mother tongue. METHODS: Using public data sources, we classified each of 267 country names and 245 mother tongues in the CIC data into 1 of 10 visible minority groups (South Asian, Chinese, black, Latin American, Filipino, West Asian, Arab, Southeast Asian, Korean, and Japanese) or a white group. We then used country of birth alone (method A) or country of birth plus mother tongue (method B) to classify 2.5 million people in the CIC database who immigrated to Ontario between 1985 and 2010 and who had a valid encrypted health card number. We validated the ethnic categorizations using linked selfreported ethnicity data for 6499 people who responded to the Canadian Community Health Survey (CCHS). RESULTS: Among immigrants listed in the CIC database, the 4 most frequent visible minority groups as classified by method B were South Asian (n = 582 812), Chinese (n = 400 771), black (n = 254 189), and Latin American (n = 179 118). Methods A and B agreed in 94% of the categorizations (kappa coefficient 0.94, 95% confidence interval [CI] 0.93-0.94). Both methods A and B agreed with self-reported CCHS ethnicity in 86% of all categorizations (for both comparisons, kappa coefficient 0.83, 95% CI 0.82-0.84). Both methods A and B had high sensitivity and specificity for most visible minority groups when validated using self-reported ethnicity from the CCHS (e.g., with method B, sensitivity and specificity were, respectively, 0.85 and 0.97 for South Asians, 0.93 and 0.99 for Chinese, and 0.90 and 0.97 for blacks). INTERPRETATION: The use of country of birth and mother tongue is a validated and practical method for classifying immigrants to Canada into ethnic categories.