Outcomes of Patients With NSTEMI and Significant CAD
Outcomes of Patients With NSTEMI and Significant CAD
The National Cardiovascular Data Registry–Acute Coronary Treatment and Intervention Outcomes Network-Get With The Guidelines (ACTION-GWTG) registry is an ongoing national database that began enrolling patients on January 1, 2007, and that receives data on consecutive patients admitted with either NSTEMI or ST-segment elevation myocardial infarction (STEMI) at participating hospitals in the United States. The population for this study was derived from the 162,361 patients enrolled in the ACTION-GWTG registry from January 1, 2007, to December 31, 2009, at 397 ACTION-GWTG hospitals. Of these hospitals, 88% were full-service hospitals with facilities for cardiac catheterization, percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). Patients were included in the registry if they had acute ischemic symptoms, had positive cardiac biomarkers, and were admitted within 24 hours of these symptoms. Patients were included in this analysis if they had NSTEMI, underwent an invasive strategy, and were found to have significant CAD but did not undergo any revascularization. The overall sample for our analysis consisted of 13,872 patients (Figure).
(Enlarge Image)
Figure.
Patient selection for the analysis. Flowchart outlining the initial population enrolled in the ACTION-GWTG registry from January 1, 2007, to December 31, 2009, at 397 ACTION-GWTG hospitals and the patients who got excluded, leading to the final population included in the analysis.
Glomerular filtration rate (GFR) was estimated via the 4-variable Modification of Diet in Renal Disease (MDRD) equation.Stage 3 CKD is defined as GFR between 30 and 59 mL/min per 1.73 m; stage 4 CKD, as GFR between 15 and 29 mL/min per 1.73 m; and stage 5 CKD, as GFR < 15 mL/min per 1.73 m or dialysis therapy. Patients were divided based on baseline renal function in 4 groups: (1) no CKD or CKD stage 1 or 2 (referred to as "no CKD" for the purpose of this study), (2) CKD stage 3, (3) CKD stage 4, and (4) CKD stage 5.
The primary outcome was the short-term in-hospital all-cause death. Moreover, we examined rates of major bleeding. Major bleeding was defined as an absolute hemoglobin (Hb) level drop of ≥ 4 g/dL (baseline to nadir), intracranial hemorrhage, documented or suspected retroperitoneal bleed, any red blood cell blood transfusion with a baseline Hb level ≥ 9 g/dL, or any red cell transfusion with a baseline Hb level < 9 g/dL and a suspected bleeding event.
Baseline demographics, clinical characteristics, in-hospital treatments, and outcomes were shown across baseline CKD groups. Continuous variables were reported as medians and 25th and 75th percentiles, and categorical variables were reported as percentages. P values were based on χ rank-based group means score statistics for all categorical variables and on χ 1 df rank correlation statistics for all continuous or ordinal variables.
To evaluate the relationship between in-hospital outcomes and CKD stages, logistic generalized estimating equations method with exchangeable working correlation matrix was used to account for within-hospital clustering because patients at the same hospital are more likely to have similar responses relative to patients at other hospitals (ie, within-center correlation for responses). This method produces estimates similar to those from ordinary logistic regression, but variances are adjusted for the correlation of outcomes within a hospital. Variables used for in-hospital mortality adjustment were derived from the validated ACTION-GWTG in-hospital mortality model: age, prior peripheral arterial disease, systolic blood pressure (SBP) on presentation, heart rate on presentation, heart failure (HF) or shock on admission (HF only, shock only, or HF with shock vs none), electrocardiographic findings (STEMI, ST-segment depression, or transient ST-segment elevation vs no ST-segment changes), initial serum creatinine, and initial troponin ratio. Variables used for major bleeding adjustment were derived from the validated ACTION-GWTG in-hospital major bleeding model: age, female sex, diabetes, prior peripheral arterial disease, home warfarin use, body weight, heart rate on presentation, SBP on presentation (SBP ≤ 130 mm Hg, SBP 130–160 mm Hg, and SBP ≥ 160 mm Hg), HF on presentation (HF only, shock only, or HF with shock vs none), elecrocardiographic findings (STEMI, ST-segment changes vs no ST-segment changes), initial serum creatinine, and baseline Hb level < 12 g/dL (vs ≥ 12 g/dL). ST-segment elevation myocardial infarction and initial serum creatinine were dropped from both models because patients with STEMI were excluded from this analysis and because CKD is a function of serum creatinine. Chronic kidney disease stages were compared with no CKD, and adjusted associations for outcomes were displayed as odds ratios (ORs) (95% CIs), and a global comparison P value was calculated and reported. All analyses were performed using SAS software (version 9.2; SAS Institute, Cary, NC).
The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the manuscript, and its final contents. No extramural funding was used to support this work.
Methods
Patient Population
The National Cardiovascular Data Registry–Acute Coronary Treatment and Intervention Outcomes Network-Get With The Guidelines (ACTION-GWTG) registry is an ongoing national database that began enrolling patients on January 1, 2007, and that receives data on consecutive patients admitted with either NSTEMI or ST-segment elevation myocardial infarction (STEMI) at participating hospitals in the United States. The population for this study was derived from the 162,361 patients enrolled in the ACTION-GWTG registry from January 1, 2007, to December 31, 2009, at 397 ACTION-GWTG hospitals. Of these hospitals, 88% were full-service hospitals with facilities for cardiac catheterization, percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). Patients were included in the registry if they had acute ischemic symptoms, had positive cardiac biomarkers, and were admitted within 24 hours of these symptoms. Patients were included in this analysis if they had NSTEMI, underwent an invasive strategy, and were found to have significant CAD but did not undergo any revascularization. The overall sample for our analysis consisted of 13,872 patients (Figure).
(Enlarge Image)
Figure.
Patient selection for the analysis. Flowchart outlining the initial population enrolled in the ACTION-GWTG registry from January 1, 2007, to December 31, 2009, at 397 ACTION-GWTG hospitals and the patients who got excluded, leading to the final population included in the analysis.
Definition of CKD and Outcome Definitions
Glomerular filtration rate (GFR) was estimated via the 4-variable Modification of Diet in Renal Disease (MDRD) equation.Stage 3 CKD is defined as GFR between 30 and 59 mL/min per 1.73 m; stage 4 CKD, as GFR between 15 and 29 mL/min per 1.73 m; and stage 5 CKD, as GFR < 15 mL/min per 1.73 m or dialysis therapy. Patients were divided based on baseline renal function in 4 groups: (1) no CKD or CKD stage 1 or 2 (referred to as "no CKD" for the purpose of this study), (2) CKD stage 3, (3) CKD stage 4, and (4) CKD stage 5.
The primary outcome was the short-term in-hospital all-cause death. Moreover, we examined rates of major bleeding. Major bleeding was defined as an absolute hemoglobin (Hb) level drop of ≥ 4 g/dL (baseline to nadir), intracranial hemorrhage, documented or suspected retroperitoneal bleed, any red blood cell blood transfusion with a baseline Hb level ≥ 9 g/dL, or any red cell transfusion with a baseline Hb level < 9 g/dL and a suspected bleeding event.
Statistical Analysis
Baseline demographics, clinical characteristics, in-hospital treatments, and outcomes were shown across baseline CKD groups. Continuous variables were reported as medians and 25th and 75th percentiles, and categorical variables were reported as percentages. P values were based on χ rank-based group means score statistics for all categorical variables and on χ 1 df rank correlation statistics for all continuous or ordinal variables.
To evaluate the relationship between in-hospital outcomes and CKD stages, logistic generalized estimating equations method with exchangeable working correlation matrix was used to account for within-hospital clustering because patients at the same hospital are more likely to have similar responses relative to patients at other hospitals (ie, within-center correlation for responses). This method produces estimates similar to those from ordinary logistic regression, but variances are adjusted for the correlation of outcomes within a hospital. Variables used for in-hospital mortality adjustment were derived from the validated ACTION-GWTG in-hospital mortality model: age, prior peripheral arterial disease, systolic blood pressure (SBP) on presentation, heart rate on presentation, heart failure (HF) or shock on admission (HF only, shock only, or HF with shock vs none), electrocardiographic findings (STEMI, ST-segment depression, or transient ST-segment elevation vs no ST-segment changes), initial serum creatinine, and initial troponin ratio. Variables used for major bleeding adjustment were derived from the validated ACTION-GWTG in-hospital major bleeding model: age, female sex, diabetes, prior peripheral arterial disease, home warfarin use, body weight, heart rate on presentation, SBP on presentation (SBP ≤ 130 mm Hg, SBP 130–160 mm Hg, and SBP ≥ 160 mm Hg), HF on presentation (HF only, shock only, or HF with shock vs none), elecrocardiographic findings (STEMI, ST-segment changes vs no ST-segment changes), initial serum creatinine, and baseline Hb level < 12 g/dL (vs ≥ 12 g/dL). ST-segment elevation myocardial infarction and initial serum creatinine were dropped from both models because patients with STEMI were excluded from this analysis and because CKD is a function of serum creatinine. Chronic kidney disease stages were compared with no CKD, and adjusted associations for outcomes were displayed as odds ratios (ORs) (95% CIs), and a global comparison P value was calculated and reported. All analyses were performed using SAS software (version 9.2; SAS Institute, Cary, NC).
The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the manuscript, and its final contents. No extramural funding was used to support this work.
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