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Background Several methodological approaches have been used to estimate distance in health service research. In this study, focusing on cardiac catheterization services, Euclidean, Manhattan, and the less widely known Minkowski distance metrics are used to estimate distances from patient residence to hospital. Distance metrics typically produce less accurate estimates than actual measurements, but each metric provides a single model of travel over a given network. Therefore, distance metrics, unlike actual measurements, can be directly used in spatial analytical modeling. Euclidean distance is most often used, but unlikely the most appropriate metric. Minkowski distance is a more promising method. Distances estimated with each metric are contrasted with road distance and travel time measurements, and an optimized Minkowski distance is implemented in spatial analytical modeling. Methods Road distance and travel time are calculated from the postal code of residence of each patient undergoing cardiac catheterization to the pertinent hospital. The Minkowski metric is optimized, to approximate travel time and road distance, respectively. Distance estimates and distance measurements are then compared using descriptive statistics and visual mapping methods. The optimized Minkowski metric is implemented, via the spatial weight matrix, in a spatial regression model identifying socio-economic factors significantly associated with cardiac catheterization. Results The Minkowski coefficient that best approximates road distance is 1.54; 1.31 best approximates travel time. The latter is also a good predictor of road distance, thus providing the best single model of travel from patient's residence to hospital. The Euclidean metric and the optimal Minkowski metric are alternatively implemented in the regression model, and the results compared. The Minkowski method produces more reliable results than the traditional Euclidean metric. Conclusion Road distance and travel time measurements are the most accurate estimates, but cannot be directly implemented in spatial analytical modeling. Euclidean distance tends to underestimate road distance and travel time; Manhattan distance tends to overestimate both. The optimized Minkowski distance partially overcomes their shortcomings; it provides a single model of travel over the network. The method is flexible, suitable for analytical modeling, and more accurate than the traditional metrics; its use ultimately increases the reliability of spatial analytical models.

The long-term incidence of heart failure (HF) in ST-elevation myocardial infarction (STEMI), non–ST-elevation myocardial infarction (NSTEMI), or unstable angina (UA) patients is uncertain. We examined the 1-year incidence of HF and its association with mortality among patients surviving their first acute coronary syndrome (ACS) hospitalization. A retrospective cohort study of patients, aged ≥20 years, with no prior HF, hospitalized for the first time with ACS between April 1, 2002, and December 31, 2008, in Alberta, Canada, and followed up for 1 year. Index HF was defined as HF that developed as a complication during the index ACS hospitalization, and post-discharge HF, as HF developing after discharge from the index ACS hospitalization. Among 9,406 STEMI, 11,008 NSTEMI, and 4,910 UA patients, 13.6%, 14.8%, and 5.2% had index HF, respectively (P < .01). At 1-year, cumulative HF rates were 23.4% in STEMI, 25.4% in NSTEMI, and 16% in UA patients. Among hospital survivors, 1-year mortality rate was 13.9% in patients with index HF, 10.6% in patients with postdischarge HF, and 2.4% in patients with no HF. In multivariable analysis, both index HF (adjusted hazard ratio 3.2, 95% CI 2.7-3.7) and postdischarge HF (adjusted hazard ratio 4.6, 95% CI 3.9-5.4) were associated with 1-year mortality. There are significant differences in the incidence of HF among STEMI, NSTEMI, and UA patients. The increased mortality risk associated with index HF and postdischarge HF suggests a need for vigilant follow-up of all ACS patients for prompt detection and treatment of HF.

Because alcohol and drug use disorders (SUDs) can influence quality of care, we compared patients with and without SUDs on frequency of catheterization, revascularization, and in-hospital mortality after acute myocardial infarction (AMI). This study employed hospital discharge data identifying all adult AMI admissions (ICD-9-CM code 410) between April 1996 and December 2001. Patients were classified as having an SUD if they had alcohol and/or drug (not nicotine) abuse or dependence using a validated ICD-9-CM coding definition. Catheterization and revascularization data were obtained by linkage with a clinically-detailed cardiac registry. Analyses (controlling for comorbidities and disease severity) compared patients with and without SUDs for post-MI catheterization, revascularization, and in-hospital mortality. Of 7,876 AMI unique patient admissions, 2.6% had an SUD. In adjusted analyses mortality was significantly higher among those with an SUD (odds ratio (OR) 2.02; 95%CI: 1.10-3.69), while there was a trend toward lower catheterization rates among those with an SUD (OR 0.75; 95%CI: 0.55-1.01). Among the subset of AMI admissions who underwent catheterization, the adjusted hazard ratio for one-year revascularization was 0.85 (95%CI: 0.65-1.11) with an SUD compared to without. Alcohol and drug use disorders are associated with significantly higher in-hospital mortality following AMI in adults of all ages, and may also be associated with decreased access to catheterization and revascularization. This higher mortality in the face of poorer access to procedures suggests that these individuals may be under-treated following AMI. Targeted efforts are required to explore the interplay of patient and provider factors that underlie this finding.

Background Surveys of patients suggest many want to be actively involved in treatment decisions for acute coronary syndromes. However, patient experiences of their engagement and participation in early phase decision-making have not been well described. Methods We performed a patient led qualitative study to explore patient experiences with decision-making processes when admitted to hospital with non-ST elevation acute coronary syndrome. Trained patient-researchers conducted the study via a three-phase approach using focus groups and semi-structured interviews and employing grounded theory methodology. Results Twenty patients discharged within one year of a non-ST elevation acute coronary syndrome participated in the study. Several common themes emerged. First, patients characterized the admission and early treatment of ACS as a rapidly unfolding process where they had little control. Participants felt they played a passive role in early phase decision-making. Furthermore, participants described feeling reduced capacity for decision-making owing to fear and mental stress from acute illness, and therefore most but not all participants were relieved that expert clinicians made decisions for them. Finally, once past the emergent phase of care, participants wanted to retake a more active role in their treatment and follow-up plans. Conclusions Patients admitted with ACS often do not take an active role in initial clinical decisions, and are satisfied to allow the medical team to direct early phase care. These results provide important insight relevant to designing patient-centered interventions in ACS and other urgent care situations.

A number of studies have identified the number of diseased vessels to be an important determinant of survival in patients with acute coronary syndrome (ACS). It is unknown if coronary dominance has an impact on prognosis of these patients. We hypothesized that the prognosis of patients with ACS with left dominance (LD) would be worse than that of patients with right or mixed dominance. The study population consisted of 27289 patients whose primary indication for cardiac catheterization was ACS. The patients were divided into 3 groups according to coronary dominance. The mean duration of follow-up was 3.5 years (range 1-6.5 years). A Cox proportional hazards analysis was used to compare survival by dominance, adjusting for age, sex, diagnosis, comorbidities, severity of coronary disease, and ejection fraction. The rates and patterns of revascularization among patients with significant coronary disease were similar between the groups. At the end of follow-up, patients with LD had a significantly higher mortality (hazard ratio 1.18, 95% CI 1.05-1.34; adjusted hazard ratio 1.13, CI 1.00-1.28). The mortality of patients with mixed and right dominance was similar. In patients with ACS, LD is a significant and independent predictor of increased long-term mortality. Further research is needed to determine mechanisms of increased mortality in patients with LD and measures that can be taken to improve the outcome of patients with left-dominant circulation.

To determine whether acute kidney injury results in later long-term decline in kidney function we measured changes in kidney function over a 3-year period in adults undergoing coronary angiography who had serum creatinine measurements as part of their clinical care. Acute kidney injury was categorized by the magnitude of increase in serum creatinine (mild (50–99% or ≥0.3mg/dl) and moderate or severe (≥100%)) within 7 days of coronary angiography. Compared to patients without acute kidney injury, the adjusted odds of a sustained decline in kidney function at 3 months following angiography increased more than 4-fold for patients with mild to more than 17-fold for those with moderate or severe acute kidney injury. Among those with an estimated glomerular filtration rate after angiography less than 90ml/min per 1.73m2, the subsequent adjusted mean rate of decline in estimated glomerular filtration rate during long-term follow-up (all normalized to 1.73m2 per year) was 0.2ml/min in patients without acute kidney injury, 0.8ml/min following mild injury, and 2.8ml/min following moderate to severe acute kidney injury. Thus, acute kidney injury following coronary angiography is associated with a sustained loss and a larger rate of future decline in kidney function.

People of South Asian (SA) ancestry are susceptible to coronary artery disease (CAD). Although studies suggest that SA with CAD has a worse prognosis compared with Europeans, it is unknown whether corresponding differences in functional status and quality-of-life (QOL) measures exist. Accordingly, we compared symptoms, function, and QOL in SA and European Canadians with CAD using the Seattle Angina Questionnaire (SAQ). Using the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease, an outcomes registry that captures patients undergoing cardiac catheterization in Alberta, Canada, we identified 635 SA and 18,934 European patients with angiographic CAD from January 1995 to December 2006 who reported health status outcomes using the SAQ at 1 year after the index catheterization. To obtain comparable clinical variables among SA and Europeans, we used a propensity score–matching technique. One-year adjusted mean (SD) scores were significantly lower in SA compared with European Canadians for most SAQ domains: exertional capacity (75 [23] vs 80 [23], P = .011), anginal stability (77 [28] vs 77 [27], P = .627), anginal frequency (86 [23] vs 88 [20], P < .001), treatment satisfaction (86 [19] vs 89 [16], P < .001), and SAQ QOL (71 [24] vs 76 [21], P < .001). These results could not be accounted for by differences in baseline QOL scores or changes in health status from baseline to 1 year. South Asian Canadians with established CAD have significantly worse health status outcomes at 1 year after angiography compared with European Canadians. Further studies are warranted to improve functional outcomes in SA with CAD.

Our objective was to examine the effect of concomitant lower extremity peripheral arterial disease (PAD) on long-term prognosis and pharmacotherapy in patients with coronary artery disease (CAD). Prospective cohort study enrolling all patients with angiographically proven CAD between April 1, 2000, and December 31, 2004, in Alberta, Canada. Of 28 649 patients (mean age 64 years) with CAD, 2509 (9%) had a physician-assigned diagnosis of lower extremity PAD. Mortality was higher in the patients with CAD and PAD over a mean follow-up of 3.1 years, even after adjusting for the fact that patients with PAD had more severe CAD and more comorbidities (adjusted hazard ratio [HR] 1.41, 95% CI 1.28-1.55). Fewer patients with CAD and PAD received antiplatelet agents (83% vs 86%, odds ratio 0.86, 95% CI 0.77-0.97) or β-blockers (63% vs 67%, odds ratio 0.89, 95% CI 0.82-0.98), but users of these agents exhibited lower mortality (adjusted HR 0.68, 95% CI 0.60-0.77, for antiplatelet agents and adjusted HR 0.72, 95% CI 0.64-0.80, for β-blockers). Approximately half of these patients were prescribed statins or angiotensin-converting enzyme inhibitors, and 27% were using all 3 evidence-based anti-atherosclerotic therapies (antiplatelets, statin, and angiotensin-converting enzyme inhibitor). In patients with CAD, lower extremity PAD is independently associated with poorer outcomes. Although all evidence-based therapies are underused in patients with CAD, patients with concomitant PAD are less likely to be prescribed antiplatelet agents or β-blockers—both agents are associated with improved survival in patients with CAD and PAD.

Multivessel coronary artery revascularization may be accomplished by percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). The importance of complete revascularization is emphasized in the surgical literature, but little is known about its impact on PCI outcomes. This study evaluated multivessel PCI patients to determine the predictors of complete revascularization and the association of complete revascularization with survival, subsequent CABG, and repeat PCI. The Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) is a clinical data collection and outcome-monitoring initiative capturing all patients undergoing cardiac catheterization and revascularization in the province of Alberta, Canada. Characteristics and long-term outcomes of 1308 patients undergoing multivessel PCI with complete revascularization were compared with those of 648 patients with incomplete revascularization. The significant independent predictors of complete revascularization were pre-PCI Duke jeopardy score, the presence of a total occlusion, year of PCI, age > 65 years, renal failure, and left ventricular function. With a median follow-up time of 3.0 ± 1.8 years, the adjusted hazard ratio (HR) (95% CI) for the association between complete revascularization and outcome was 0.75 (0.54-1.04) for death, 0.55 (0.37-0.84) for subsequent CABG, and 0.93 (0.65-1.34) for repeat PCI. Baseline angiographic characteristics and other clinical factors can predict complete revascularization in patients undergoing multivessel PCI. Complete multivessel PCI is associated with reduced need for future CABG, a trend toward better survival, and no difference in repeat PCI.

Background: Census-based measures of income often are used as proxies for individual-level income. Yet, the validity of such area-based measures relative to 'true' individual-level income has not been fully characterized. Objectives: The objectives of this study were (1) to determine whether area-based measures of household income are a suitable proxy for self-reported household income and (2) to assess whether these measures are associated with outcomes in a cardiac disease cohort. Research Design: We used a prospective cohort from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH©) cardiac catheterization registry. Subjects: A total of 4372 patients having undergone cardiac catheterization and who also completed a 1-year follow-up questionnaire on self-reported income level were studied. Measures: Our measurements were survival to 2.5 years after catheterization and health-related quality of life (EuroQoL). Results: Agreement between the 2 income measures generally was poor (unweighted Kappa = 0.07), particularly for the low-income patients. Despite this poor agreement, both income measures were positively associated with survival and EuroQoL scores. An outcome analysis that simultaneously considered individual level income and area-based income revealed that low-income individuals have poorer survival and lower quality of life scores if they live in low income neighborhoods, but not if they live in high income neighborhoods. Conclusions: The area-based estimates of household income in these data demonstrate poor agreement with self-reported household income at the level of individual patients, particularly for low-income patients. Despite this, both income measures appear to be prognostically relevant, perhaps because individual and neighborhood income measure different constructs.