Methods

Full details of the methods of GRACE have been published elsewhere. GRACE is designed to reflect an unbiased population of patients with ACS. Patients enrolled in the GRACE registry were ≥18 years of age, were alive at the time of presentation, and presented with symptoms suggestive of coronary ischemia. In addition to symptoms, patients were required to have electrocardiographic changes consistent with ACS, elevation of serum cardiac biomarkers of myocardial necrosis, or documented coronary artery disease. ACS precipitated by noncardiovascular co-morbidities, such as anemia or trauma, were excluded. To enroll an unselected population, the first 10 to 20 consecutive eligible patients were recruited from each site per month. Data were collected by trained coordinators using a standardized case report forms. Demographic characteristics, medical history, presenting symptoms, biochemical and electrocardiographic findings, treatment practices, and a variety of hospital outcome data were collected. Selected study outcomes were assessed 6 months after discharge. Standardized definitions for all patient-related variables and clinical diagnoses were used.

For this analysis, we limited our study to the Australian and New Zealand population enrolled in the GRACE registry from 1999 to 2007. We included all patients with discharge diagnoses of NSTEACS (non–ST-segment elevation myocardial infarction and unstable angina) on the basis of previous published criteria. We included patients who directly presented to the hospital as well as patients transferred from outlying hospitals. The primary outcomes for this study were rates of in-hospital investigations and procedures (coronary angiography, percutaneous coronary intervention [PCI], coronary artery bypass surgery, echocardiography, and exercise stress testing), guideline-based in-hospital medication use (aspirin, thienopyridine, unfractionated heparin, low–molecular weight heparin, glycoprotein IIb/IIIa inhibitors, β blockers, statins, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers), and referral to cardiac rehabilitation on discharge.

Our study cohort was derived from 11 metropolitan centers, of which 8 (73%) were teaching hospitals with onsite cardiac catheterization facilities. Five of 11 centers (45%) had onsite cardiac surgical facilities. At noninterventional and nonsurgical sites, it would be routine practice to transfer patients for angiography and revascularization (PCI or coronary artery bypass grafting). To account for these centers, our rates of coronary angiography, PCI, and coronary artery bypass grafting included patients if they were referred to other hospitals for the procedures or underwent the procedures as outpatients, provided these were booked from the index admissions. For all other investigation and medications, patients were considered only if they underwent the investigations or received the medications during the index admission.

Data are summarized as frequencies and percentages for categorical variables. Continuous variables are presented as mean ± SD for normally distributed data. Otherwise, data are presented as medians and 25th and 75th percentiles. For evaluation of temporal trends, the enrollment period was divided into 3 yearly groups (1999 to 2001, 2002 to 2004, and 2005 to 2007). Patients were stratified according to their levels of risk at presentation (low, intermediate, and high risk) according to the GRACE risk score for in-hospital death using previously published cut-off values. Chi-square statistics were used to evaluate differences among risk groups for each year group. Furthermore, the temporal trend (increase or decrease) in the outcome variable across year groups for each risk category was evaluated. Trend analysis was performed using the double-sided Cochran-Armitage test or logistic regression. A p value <0.05 was used as a cutoff for statistical significance. The analysis was performed using SAS version 9.1 (SAS Institute Inc., Cary, North Carolina). Data were >98% complete for all variables, with the exception of referral for cardiac rehabilitation, for which complete data are available only from 2000 onward. To account for possible changes in baseline risk, we calculated the average GRACE risk score for in-hospital death for each year of enrollment. Although there was a slight increase in baseline risk, this failed to reach statistical significance (p = 0.055).

Results

A total of 3,982 patients with discharge diagnoses of NSTEACS (2,098 with non–ST-segment elevation myocardial infarctions, 1,794 with unstable angina) were enrolled in the Australian and New Zealand population of GRACE from 1999 to 2007. Of these, 330 had missing data for ≥1 of the components of the GRACE risk score for in hospital death and were excluded. The remaining 3,562 were included in the study. The population was stratified on the basis of the GRACE risk score for in-hospital mortality ( Table 1 ), and a gradient of risk characteristics was observed. Risk stratification on the basis of the GRACE risk score appropriately predicted in-hospital death, congestive heart failure, and renal failure ( Table 2 ) and death at 6 months. Presentation risk was not associated with risk for in-hospital stroke (p = 0.54) or major bleeding (p = 0.18).

Changes in investigations and revascularization procedures over time stratified according to the baseline risk of the patients are shown in Figure 1 and listed in Table 3 . In-hospital referral for exercise stress testing was concordant with risk with the low-risk group consistently having the highest rates of exercise stress testing ( Figure 1 ). Overall, the rate of referral for exercise stress testing was low. Referral for echocardiography showed a temporal increase in the referral rate across all risk groups ( Figure 1 ). Referral was concordant with patient risk, with more high-risk patients than low-risk patients undergoing echocardiography.

(A) Rates of exercise stress testing. No significant trend was observed within risk groups (low risk p = 0.12, intermediate risk p = 0.73, high risk p = 0.09). (B) Rates of echocardiography. An increasing trend was noted within all risk groups (p <0.001 for all groups). (C) Rates of coronary angiography (CA). An increasing trend was seen within all risk groups (low risk p = 0.047, intermediate risk p = 0.013, high risk p <0.001). (D) Rates of PCI (all patients). An increasing trend was observed in the low-risk (p = 0.004) and intermediate-risk (p = 0.031) groups but not in the high-risk group (p = 0.146). (E) Rates of PCI limited to patients who underwent CA. An increasing trend increase was observed in the low-risk group (p = 0.003) but not in the intermediate-risk (p = 0.188) or high-risk (p = 0.635) group. (F) Rates of coronary artery bypass grafting. No trend was noted within risk categories.

Table 3

Temporal trends within each risk category from 1999 to 2001 to 2005 to 2007

Variable	Presenting risk category
	Low		Intermediate		High
	% Change	p Value for Trend	% Change	p Value for Trend	% Change	p Value for Trend
Procedures
Exercise stress testing	−3.43%	0.119	0.60%	0.727	−3.00%	0.092
Echocardiography	13.1%	<0.001	11.4%	<0.001	15.0%	<0.001
Coronary angiography	6.2%	0.047	7.6%	0.013	13.7%	0.001
PCI (all)	8.0%	0.004	6.4%	0.031	4.0%	0.146
PCI (catheterization+)	11.9%	0.003	6.7%	0.188	3.2%	0.635
Coronary artery bypass grafting	0.1%	0.768	4.3%	0.038	1.4%	0.425
Medications or referral to rehabilitation
Aspirin	−0.9%	0.378	−0.5%	0.852	2.9%	0.244
Thienopyridines	45.0%	<0.001	47.4%	<0.001	40.2%	<0.001
Glycoprotein IIb/IIIa inhibitors	5.1%	0.008	2.5%	0.108	2.4%	0.124
Low–molecular weight heparin	−2.3%	0.405	6.2%	0.024	1.6%	0.653
Unfractionated heparin	−17.6%	<0.001	−15.5%	<0.001	−15.1%	<0.001
β blockers	7.3%	0.002	9.8%	0.001	12.4%	0.000
ACE inhibitors or ARBs	28.4%	<0.001	17.9%	<0.001	15.9%	<0.001
Statins	15.2%	<0.001	24.4%	<0.001	29.1%	<0.001
Referral to cardiac rehabilitation	24.2%	<0.001	11.3%	<0.001	21.6%	<0.001

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. ST-Segment Deviation in Lead aVR on Admission Is Not Associated With Left Ventricular Function at Predischarge in First Anterior Wall ST-Segment Elevation Acute Myocardial Infarction
2. Comparison of the Relation Between the Calcium Score and Plaque Characteristics in Patients With Acute Coronary Syndrome Versus Patients With Stable Coronary Artery Disease, Assessed by Computed Tomography Angiography and Virtual Histology Intravascular Ultrasound
3. Population-Level Incidence and Risk Factors for Pulmonary Toxicity Associated With Amiodarone
4. Prediction of Response to Cardiac Resynchronization Therapy Combining Two Different Three-Dimensional Analyses of Left Ventricular Dyssynchrony

Stay updated, free articles. Join our Telegram channel

Join