Author + information
- Received February 2, 2017
- Revision received March 17, 2017
- Accepted March 23, 2017
- Published online July 3, 2017.
- Abhishek C. Sawant, MD, MPHa,
- Kevin Joseyb,
- Mary E. Plomondon, PhDb,
- Thomas M. Maddox, MD, MScb,
- Aishwarya Bhardwaj, MDa,
- Vasvi Singh, MDa,
- Bharath Rajagopalan, MDa,
- Zaid Said, MDa,
- Deepak L. Bhatt, MD, MPHc and
- John Corbelli, MDa,d,∗ ()
- aState University of New York at Buffalo, Buffalo, New York
- bEastern Colorado Health Care System, Denver VA Medical Center, Denver, Colorado
- cBrigham and Women’s Hospital Heart & Vascular Center and Harvard Medical School, Boston, Massachusetts
- dWestern New York Healthcare System, Buffalo VA Medical Center, Buffalo, New York
- ↵∗Address for correspondence:
Dr. John Corbelli, Buffalo VA Medical Center, 3495 Bailey Avenue, Buffalo, New York 14215.
Objectives The aim of this study was to determine temporal trends, in-laboratory complications, mortality, and predictors of mortality among nonagenarians undergoing percutaneous coronary intervention (PCI).
Background Nonagenarians (patients 90 years of age or older) undergoing PCI are often underrepresented in clinical trials, and their management remains challenging and controversial.
Methods All veterans undergoing PCI with data recorded in the Veterans Affairs Clinical Assessment, Reporting, and Tracking program from 2005 to 2014 were evaluated. Temporal trends in the use of PCI, occurrence of in-laboratory complications, and 30-day and 1-year mortality were assessed. Using a frailty model, predictors of 30-day and 1-year mortality in nonagenarians were evaluated.
Results Among all veterans undergoing PCI (n = 67,148) between 2005 and 2014, 274 (0.4%) were nonagenarians. The proportion of nonagenarians increased from 0.25% in 2008 to 0.58% in 2014. Compared with younger patients, nonagenarians had a greater risk for acute cardiogenic shock post-procedure (0.73% vs. 0.12%; p = 0.04) and no reflow (2.9% vs. 1.0%; p = 0.02). Unadjusted (10.6% vs. 1.4%; p < 0.0001) and adjusted 30-day mortality (odds ratio: 2.14; 95% confidence interval [CI]: 1.42 to 3.22) and unadjusted (16.3% vs. 4.2%; p < 0.0001) and adjusted 1-year mortality (odds ratio: 1.82; 95% CI: 1.27 to 2.62) were higher among PCI patients who were nonagenarians. The National Cardiovascular Data Registry risk score was highly predictive of both 30-day (hazard ratio: 2.29; 95% CI: 1.86 to 2.82) and 1-year (hazard ratio: 1.43; 95% CI: 1.07 to 1.90) mortality among nonagenarians.
Conclusions Nonagenarians were a small but growing population with worse 30-day and 1-year mortality. The National Cardiovascular Data Registry risk score was a strong predictor of mortality in these patients.
Percutaneous coronary intervention (PCI) has been successfully used in the treatment of acute coronary syndromes (ACS) and refractory angina for more than 30 years. With increasing life expectancy, the number of nonagenarians (i.e., patients 90 years of age or older) is expected to more than quadruple from 2010 to 2050 (1). As the population continues to age, an increasing incidence of risk factors, including smoking, hypertension, diabetes, and low physical activity, will contribute to a significant increase in coronary artery disease (CAD) in this demographic. Correspondingly, there has been an increase in the number of PCIs performed in nonagenarians (2). However, current data regarding the utilization of PCI in nonagenarians are lacking. Clinical trials on the effectiveness of PCI in the treatment of ACS and stable CAD do not adequately enroll nonagenarian patients, and management often remains challenging and controversial (3). Often nonagenarians have multiple comorbid conditions and delays in coronary revascularization (4,5). Additionally, older patients are likely to have a higher incidence of post-procedural complications because of multiple comorbidities. The incidence of major adverse cardiovascular events (6), including death and myocardial infarction (MI), compared with medical therapy has not been clearly established in nonagenarians. Last, it remains unclear what predictors of mortality among nonagenarians can be used to identify those at higher risk for adverse outcomes.
Given the paucity of nationwide data on the utilization of PCI, the occurrence of complications, and long-term outcomes in nonagenarians, we designed a study using the national database of the Veterans Affairs (VA) Clinical Assessment, Reporting, and Tracking (CART) program. The purpose of this study was to determine: 1) the prevalence of nonagenarians undergoing PCI between 2005 and 2014; 2) the annual rates of nonagenarians among all PCI patients from 2008 to 2014; 3) the clinical characteristics, occurrence of in-laboratory complications, short-term (30-day) and long-term (1-year) mortality after PCI in nonagenarians, compared with younger patients; and 4) their predictors of short- and long-term mortality.
All veterans (n = 67,148) undergoing PCI from January 2005 to December 2014 were identified using the CART program. The CART program was initially launched in 2005 and is a national clinical quality initiative for all VA cardiac catheterization laboratories. The program’s primary focus is on coronary procedures conducted in all VA cardiac catheterization laboratories nationwide (7). A key feature of the CART program is a clinical software application designed to collect standardized data on all coronary angiograms and PCI procedures. The software is embedded in the VA electronic health record and allows providers to enter patient and procedural information (pre-procedure assessment, coronary angiography, and PCI) as part of routine clinical work flow. The CART software was designed using standardized definitions that conform to the definitions and standards of the American College of Cardiology’s National Cardiovascular Data Registry (NCDR) and incorporates features such as pull-down menus and automated clinical report generation to ensure uniformity of data entry by different providers and in different cardiac catheterization laboratories (8). However, in contrast to NCDR, participation in CART is mandatory and universal in all VA cardiac catheterization laboratories. Quality checks of the data are periodically conducted for completeness and accuracy (9).
Temporal trends and site volume characteristics
We evaluated the proportion of PCI patients who were nonagenarians from 2008 to 2014. The trend analysis began in 2008, rather than 2005, because 2008 was the first year when all VA catheterization laboratories started consistently contributing PCI data to the CART program. Additionally, we compared the proportion of PCI patients who were nonagenarians stratified by quartiles of site volume of PCI performed among the 70 cardiac catheterization laboratories.
Patient and procedural characteristics
Clinical, laboratory, noninvasive, and angiographic data were obtained on all patients according to the CART program standardized protocol described earlier. Detailed clinical data, including cardiogenic shock at presentation, cardiac history, comorbid conditions, and cardiac risk factors including tobacco use, were collected for each patient. Noninvasive data and echocardiographic variables with assessment of left ventricular ejection fraction were obtained. Detailed angiographic data collected per CART protocol included type of sedation, primary arterial access site, angiographic findings, PCI, and additional procedures performed. Occurrences of in-laboratory complications including MI, death, acute cardiogenic shock, stroke, coronary dissection or perforation, and no reflow were collected. Patients on dialysis were excluded, because we were interested in measuring post-procedural creatinine and renal function.
Post-procedural unadjusted and adjusted short-term (30-day) and long-term (1-year) mortality rates among PCI patients who were nonagenarians and younger patients were assessed. Next, we evaluated the use of NCDR CathPCI score for risk stratification of PCI patients who were nonagenarians. NCDR CathPCI (10) covariates (formulated as a composite risk score containing prior congestive heart failure, peripheral vascular disease, chronic lung disease, glomerular filtration rate, New York Heart Association class IV status, and PCI status [ST-segment elevation myocardial infarction (STEMI) or non–ST-segment elevation myocardial infarction]) were used to determine risk-adjusted mortality. The NCDR CathPCI risk score provides a comprehensive assessment of multiple risk factors and has shown excellent discrimination for evaluating post-PCI mortality and has been prospectively validated (10), although it has not been previously studied for prognostication in nonagenarian patients. All procedures were approved and monitored by CART and the Buffalo VA Healthcare System Institutional Review Board, with a waiver of the requirement to obtain individual informed consent.
Categorical variables are reported as frequency (percentage), and comparison between groups were performed using chi-square tests of independence. Continuous variables are summarized as mean ± SD and were compared across groups (age <90 and ≥90 years) using a 2-sample Student t test. Temporal trends and site volume trends for PCI patients who were nonagenarians were evaluated using the Cochran-Armitage test for trend. Two hierarchical logistic regression models were fit to 30-day and 1-year all-cause mortality using generalized estimating equations adjusting for age (dichotomized as <90 and ≥90 years) and NCDR CathPCI risk score. The 1-year analysis excluded patients that died within the first 30 days post-index procedure. Outcomes were clustered by catheterization lab to account for significant correlation between patients within the same catheterization laboratory.
Next, a frailty model was fit to 30-day all-cause mortality adjusted for NCDR CathPCI risk score among the nonagenarian patient subgroup. A frailty model was also fit for 1-year mortality among nonagenarian patients adjusted for NCDR CathPCI risk score. Similar to the hierarchical logistic regression models, nonagenarian patients who died within the first 30 days after the initial procedure were omitted from the 1-year analysis. The random frailty terms are shared between patients at the same catheterization laboratory to account for significant variation in the rate of death between sites. Both 30-day and 1-year post-PCI survival was examined using Kaplan-Meier estimates comparing survival times among nonagenarians stratified by quartiles of NCDR CathPCI risk score. Difference in survival between groups was evaluated using a log-rank test. A p value <0.05 was considered to indicate statistical significance. SPSS version 22 (SPSS, Chicago, Illinois), R version 3.3.1 (R Foundation for Statistical Computing, Vienna, Austria), and SAS version 9.4 (SAS Institute, Cary, North Carolina) were used.
From 2005 to 2014, there were 67,148 veterans who underwent PCI. Among the 804 nonagenarians who underwent cardiac catheterization from 2005 to 2014, 274 (34%) proceeded to PCI. As shown in Table 1, the majority of patients were men (98.3%) and Caucasians (81.2%). Compared with younger veterans, nonagenarians had lower values of body mass index and were less likely to be smokers, to have diabetes, to have hyperlipidemia, and to have family histories of CAD. Nonagenarians were more likely to have histories of hypertension, systolic heart failure, cerebrovascular disease, and chronic kidney disease compared with younger patients. Nonagenarians had a higher incidence of cardiogenic shock (2.6% vs. 0.5%; p < 0.001) on presentation and a higher incidence of renal failure (31.8% vs. 10.3%; p < 0.001). Compared with younger patients, nonagenarians were less likely to have undergone prior cardiac catheterization or PCI but had similar rates of prior coronary artery bypass grafting (Table 1).
Temporal trends and site volume characteristics
The number of PCIs performed in nonagenarians showed an upward trend from 2008 to 2014, as outlined in Figure 1A (p for trend <0.0001, Cochran-Armitage test). The number of PCIs performed in nonagenarians remained steady from 2008 to 2010, with an upward trend, and was highest in 2013 (0.71%) and subsequently dropped in 2014 (0.58%). Next we compared the proportion of nonagenarians undergoing PCI on the basis of site volume quartiles. As shown in Figure 1B, the proportion of nonagenarians undergoing PCI did not differ significantly between sites with the lowest quartile and the highest quartile by volume of procedures performed (p trend <0.07, Cochran-Armitage test).
As shown in Table 2, PCI patients who were nonagenarians were more likely to present with ACS (2.2% vs. 1.2%), STEMI (14.6% vs. 6.9%), and non–ST-segment elevation MI (39.1% vs. 19.3%), compared with younger patients (p < 0.001). The femoral artery was the most commonly chosen site for arterial access and did not differ (89.4% vs. 85.8%; p = 0.39) between PCI patients who were nonagenarians and younger patients. Use of fractional flow reserve to determine the functional severity of stenosis did not differ (3.6% vs. 6.7%; p = 0.06) between the 2 groups. Upon presentation, performance of single-vessel PCI (64.6% vs. 67.6%), 2-vessel PCI (24.5% vs. 23.8%), and multivessel PCI (10.9% vs. 8.6%) did not differ significantly between PCI patients who were nonagenarians and younger patients (p = 0.34).
As shown in Table 3, PCI patients who were nonagenarians were more likely to develop acute cardiogenic shock (0.73% vs. 0.12%; p = 0.04) and no reflow post-PCI (2.9% vs. 1%; p = 0.02) compared with younger adults. However, overall post-PCI complication rates were very low among nonagenarians. Additionally, among all nonagenarians, there were no events of in-laboratory MI, death, stroke, cardiac tamponade, or coronary perforation post-PCI. Among all patients, glomerular filtration rate at presentation was significantly lower (58.8 mg/dl vs. 75.7 mg/dl; p < 0.001) among nonagenarians compared with younger veterans. However, at 30-day post-procedural follow-up, glomerular filtration rate did not change significantly between the 2 groups (Table 3).
Among all veterans undergoing PCI (n = 67,148), crude post-procedural all-cause mortality at 30 days and 1 year was 973 (1.4%) and 2,782 (4.2%), respectively. Table 4 outlines the clinical characteristics of PCI patients who were nonagenarians stratified by 30-day mortality. As shown in Figure 2, post-procedural unadjusted 30-day mortality was significantly higher in PCI patients who were nonagenarians compared with younger patients (10.6% vs. 1.4%; p < 0.0001). Additionally, unadjusted 1-year mortality was also significantly higher in PCI patients who were nonagenarians (16.3% vs. 4.2%; p < 0.0001) compared with younger patients. After risk adjustment, nonagenarians continued to have worse 30-day mortality (odds ratio: 2.14; 95% confidence interval [CI]: 1.42 to 3.22) and worse 1-year mortality (odds ratio: 1.82; 95% CI: 1.27 to 2.62) among those who survived at least 30 days post–index procedure. In a multivariate frailty model, NCDR risk score was highly predictive of both 30-day (hazard ratio: 2.29; 95% CI: 1.86 to 2.82) and 1-year (hazard ratio: 1.43; 95% CI: 1.07 to 1.90) mortality among nonagenarians.
Figure 3A demonstrates short-term (30-day) survival among nonagenarians after PCI stratified by quartiles of NCDR CathPCI risk scores. As shown in Figure 3A, those nonagenarians who had the highest quartile (40 to 95 points) pre-procedural NCDR CathPCI risk score had significantly worse 30-day survival compared with those patients with lower scores (log-rank p < 0.001). Figure 3B demonstrates long-term (1-year) survival among nonagenarians (contingent on their survival for 30 days) after PCI stratified by quartiles of NCDR CathPCI risk scores. Among those patients surviving at 30 days, mortality was worse among patients with higher quartile NCDR CathPCI risk scores, although this did not reach statistical significance (log-rank p = 0.07).
Our study was designed to evaluate the prevalence, clinical characteristics, complications, and long-term outcomes of selected nonagenarian PCI patients by using a national VA database and represents the largest cohort of nonagenarians undergoing PCI from the VA health care system. The key findings of our study are as follows: 1) the number of PCI patients who are nonagenarians has been rising since 2011 and at least doubled from 2010 through 2014; 2) overall complication rates post-PCI were very low among nonagenarians, without any events of in-laboratory MI, death, stroke, cardiac tamponade, or coronary perforation post-PCI; 3) nonagenarians had worse risk adjusted short-term (30-day) as well as long-term (1-year) mortality compared with younger adults after PCI; and 4) NCDR CathPCI risk score, which was not previously validated in nonagenarian patients, was found to be highly predictive of both 30-day and 1-year mortality, and nonagenarians with the highest quartile NCDR risk scores (40 to 95 points) had the worst survival at 30 days and 1 year.
Increase in PCI among nonagenarians
The use of PCI in nonagenarians has been increasing globally for both ACS and stable angina (11,12). A retrospective study evaluating trends in PCI among patients presenting with STEMI from the NIS (National Inpatient Sample) database from 2001 to 2010 showed a significant decline in the proportion of patients presenting with STEMI, especially among patients 80 years of age and older (13). However, the use of PCI among adults ≥80 years of age continued to rise, even after adjusting for comorbidities. Similarly, 19-year follow-up data on all nonagenarians undergoing PCI at the Mayo Clinic demonstrated that the use of PCI in nonagenarians from 1988 to 2006 was steadily increasing (2). In a large prospective AMIS (Acute Myocardial Infarction in Switzerland) cohort, there was a significant (3.6-fold) increase in nonagenarians undergoing primary PCI. Additionally, compared with patients 70 to 79 and 80 to 89 years of age, the highest relative increase was seen in nonagenarians from 2001 to 2012 (14). In our cohort, 34% of nonagenarians who underwent angiography proceeded to PCI. Additionally, the use of PCI remained steady from 2008 to 2010 but increased from 2011 through 2014, with at least a doubling of the number of nonagenarians undergoing PCI. Thus, our study adds to a growing body of research supporting increased use of PCI among nonagenarians.
By virtue of advanced age, nonagenarians are at higher risk for developing post-procedural complications, including acute kidney injury, bleeding, and stroke, compared with younger patients (15,16). Among 5,557 nonagenarians presenting with ACS from the CRUSADE registry, the adjusted risk for major bleeding and in-hospital stroke was lower among nonagenarians, without any difference in the risk for post-procedural MI and cardiogenic shock compared with patients 75 to 89 years of age (17). A recent multicenter retrospective study from Europe also reported angiographic success in 86% of patients, with low complication rates of bleeding (4%), stroke (1%), and recurrent MI (1%) in their cohort of 145 nonagenarians, whereas no reflow occurred in 8% of patients. Lee et al. (18) demonstrated angiographic success in 100% of their cases, while large registry studies have shown high procedural success rates as well (11). Similarly, in our cohort, no patients developed in-laboratory MI or stroke, and no reflow occurred in only 2.9% of patients. These studies, along with our data, support the safety of performing PCI in nonagenarians.
Short- and long-term mortality
Advanced age remains a universal predictor of death after PCI, with significant comorbidities contributing to the increased mortality rates in this population. In the CRUSADE registry, mortality was worse among nonagenarians, although patients who underwent revascularization within 48 h of presentation had favorable outcomes (17). Likewise, in our cohort, nonagenarians had worse short-term (30-day) and long-term (1-year) survival compared with younger adults. After adjusting for potential confounders, nonagenarians were still more likely to die compared with younger adults after PCI. In a longitudinal follow-up study from the Mayo Clinic, the investigators found an in-hospital mortality rate of 9.4% among nonagenarians undergoing PCI. However, in-hospital mortality did not differ compared with octogenarians (80 to 89 years of age) undergoing PCI. Although PCI has been validated for treatment of angina in elderly patients, those presenting with cardiogenic shock have the worst survival (19,20). Likewise, in our cohort, all nonagenarians who presented with cardiogenic shock before PCI did not survive at 30-day follow-up. Our findings add to the growing body of evidence supporting the medical futility of performing PCI in nonagenarians presenting with cardiogenic shock.
In a meta-analysis of 10 observational studies, Presutti et al. (21) found an in-hospital mortality rate of 12.61% and a significantly high 1-year mortality rate of 31%. In our cohort, we found a similar short-term (30-day) mortality rate of 10.6%, but long-term (1-year) mortality was much lower at 16.3% among veterans. These findings are reassuring, because although in-hospital and short-term mortality rates among nonagenarians may be high, likely in part because of multiple comorbidities, once they survive beyond 30 days, their prognosis is relatively better. Additionally, our results highlight that veterans throughout the nation receive high-quality cardiac care and management of CAD with at-par or better outcomes, even in high-risk subgroups such as nonagenarians.
Predictors of mortality
The presence of multiple comorbidities among nonagenarians increases their risk for adverse outcomes post-PCI compared with younger adults. Hence, the need to identify patients who are at higher risk for adverse outcomes post-PCI is paramount. Several studies have attempted to risk-stratify patients undergoing PCI and have developed scores for risk prediction (22,23). However, data regarding risk stratification among nonagenarians before PCI are lacking in current research. We identified NCDR CathPCI score, which has been previously validated in several studies (10), to be a strong predictor of both short- and long-term mortality among nonagenarians. The NCDR risk score variables (age, cardiogenic shock, prior heart failure, peripheral vascular disease, chronic lung disease, glomerular filtration rate, New York Heart Association functional class, and PCI status) are routinely collected as part of the CART registry and can be quickly used to predict risk at the bedside before making decisions regarding performing PCI. In our nonagenarian cohort, for every 10-point increase in NCDR risk score, there were 2.3- and 1.4-fold increases in the risk for 30-day and 1-year mortality, respectively. Also, nonagenarians with the highest quartile risk scores had worse survival at 30 days and 1 year. Although the NCDR risk score has not been previously validated in nonagenarians, our study highlights the importance of risk stratification in nonagenarians undergoing PCI and demonstrates the NCDR CathPCI score to be of prognostic significance in this subgroup.
Because the study population was limited to veterans, women were underrepresented in this study. The study population was selected from a registry and hence may not be representative of the general population. For example, veterans have a higher proportion of cardiovascular risk factors, including smoking. Despite the presence of a higher proportion of comorbidities, nonagenarian veterans undergoing PCI had comparable short-term and lower long-term mortality than demonstrated in previous studies. Because of the retrospective nature of the study, there is potential for selection bias inherent to the study design. Nonagenarians who did not undergo cardiac catheterization and hence were not included in the CART registry could likely be sicker and have worse outcomes. Although we attempted to adjust for measured confounders, the outcomes among nonagenarians remained unchanged after risk-adjusted analysis. The CART registry captures only in-laboratory complications, and there could be underreporting of complications that occur during the periprocedural period. We used frailty models to adjust for the variability among cardiac catheterization laboratories in the VA system. However, these models can only approximate the variability regarding performance of PCI in nonagenarians seen at various VA facilities. Additional factors, including psychosocial and financial variables and operator preferences, cannot be fully accounted for in these models.
In a national cohort of veterans undergoing PCI, we found that there was an increasing trend in the use of PCI in nonagenarians. Occurrence of in-laboratory complications was infrequent among these selected nonagenarians as well. Nonagenarians undergoing PCI had worse 30-day and 1-year mortality compared with younger adults. However, survival was comparable at 30 days and better at 1 year compared with previously published findings. Finally, NCDR CathPCI risk score was identified as a strong predictor of short-term and long-term mortality and had prognostic significance in nonagenarians undergoing PCI. However, the role of NCDR CathPCI score in risk stratification needs further prospective validation in this population.
WHAT IS KNOWN? Nonagenarians undergoing PCI have increased risk for complications and adverse events compared with younger adults inherent to advanced age and the presence of multiple comorbidities.
WHAT IS NEW? We present the utilization trends, in-laboratory complications, mortality, and predictors of mortality among PCI patients who were nonagenarians in a national cohort of VA patients. We also demonstrated that the NCDR CathPCI score is a good predictor of mortality, which has not been previously validated in this cohort of patients.
WHAT IS NEXT? Future prospective studies evaluating the role of the NCDR CathPCI score for risk stratification of nonagenarians undergoing PCI are warranted.
The authors thank Lori Grove, MT, CCRP, for her invaluable help regarding obtaining VA Institutional Review Board approval. This is the result of work supported with resources and the use of facilities at the Western New York Healthcare System, Buffalo VA Medical Center. The contents do not represent the views of the VA or the U.S. government.
This study was funded by the Thomas F. Frawley, MD, Research Fellowship Fund awarded to Dr. Sawant. Dr. Bhatt is a member of the advisory boards of Cardax, Elsevier Practice Update Cardiology, Medscape Cardiology, and Regado Biosciences; is a member of the boards of directors of the Boston VA Research Institute and the Society of Cardiovascular Patient Care; is chair of the American Heart Association Quality Oversight Committee; is a member of the data monitoring committees of the Duke Clinical Research Institute, the Harvard Clinical Research Institute, the Mayo Clinic, and the Population Health Research Institute; has received honoraria from the American College of Cardiology (senior associate editor, Clinical Trials and News, ACC.org), Belvoir Publications (Editor-in-Chief, Harvard Heart Letter), the Duke Clinical Research Institute (clinical trial steering committees), the Harvard Clinical Research Institute (clinical trial steering committee), HMP Communications (editor-in-chief, Journal of Invasive Cardiology), the Journal of the American College of Cardiology (guest editor, associate editor), the Population Health Research Institute (clinical trial steering committee), Slack Publications (chief medical editor, Cardiology Today’s Intervention), the Society of Cardiovascular Patient Care (secretary/treasurer), and WebMD (continuing medical education steering committees); is deputy editor of Clinical Cardiology; is chair of the National Cardiovascular Data Registry ACTION Registry Steering Committee; is chair of the VA CART Research and Publications Committee has received research funding from Amarin, Amgen, AstraZeneca, Bristol-Myers Squibb, Eisai, Ethicon, Forest Laboratories, Ischemix, Eli Lilly, Medtronic, Pfizer, Roche, Sanofi, and The Medicines Company; has received royalties from Elsevier (editor, Cardiovascular Intervention: A Companion to Braunwald’s Heart Disease); is a site co-investigator for Biotronik, Boston Scientific, and St. Jude Medical; is a trustee of the American College of Cardiology; and has conducted unfunded research for FlowCo, PLx Pharma, and Takeda. Dr. Maddox is the national director of the VA CART program. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- acute coronary syndrome(s)
- coronary artery disease
- Clinical Assessment, Reporting, and Tracking
- confidence interval
- myocardial infarction
- National Cardiovascular Data Registry
- percutaneous coronary intervention
- ST-segment elevation myocardial infarction
- Veterans Affairs
- Received February 2, 2017.
- Revision received March 17, 2017.
- Accepted March 23, 2017.
- 2017 American College of Cardiology Foundation
- ↵He W, Muenchrath MN. 90+ in the United States: 2006–2008. Available at: https://www.census.gov/library/publications/2011/acs/acs-17.html. Accessed August 10, 2016.
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