ST-Elevation and Non-ST-Elevation Myocardial Infarction Clinical Performance Measures: Promise for Progress
Disclosure: Member, Writing Group, NSTEMI Guideline
Pub Date: Monday, November 10, 2008
Author: Nanette Kass Wenger, MD, FACC, FAHA, MACP
There is an estimated incidence of 600,000 new patients who will sustain a myocardial infarction (MI) and 320,000 who will have an episode of recurrent MI annually in the United States, incurring $31 billion in hospital costs. This challenges all health-care providers to promote and encourage the implementation of best treatments and strategies, translating new scientific knowledge to bedside care; this is the focus of improvement of the quality of health care.
The 2008 American College of Cardiology/American Heart Association (ACC/AHA) clinical performance measures for patients with ST-elevation (STEMI) and non-ST-elevation myocardial infarction (non-STEMI) (an update of the 11 performance measures in the 2006 report) address the dimensions of care that include diagnostics, patient education, and treatment, with attention directed to structures of care (e.g., protocols) for acute myocardial infarction (AMI) and clinical outcomes.
Why Is Quality Improvement Important and How Should These Measures Be Used?
Abundant evidence links improved clinical outcomes to the application of evidence-based medicine and adherence to guideline recommendations. Such implementation has been documented to lessen morbidity, mortality, and hospital stay and to reduce health-care costs. These features buttress the need to assess clinical performance in the care of patients with AMI and to adjust clinical practice patterns accordingly. The performance measures are designed to facilitate the application of this evidence-based knowledge and to provide continuing assessment of improvement in treatments and strategies.
The ACC/AHA guideline recommendations for patients with AMI were translated into process measures reflecting current ACC/AHA clinical data standards.[3,4] Requirements for the selection of performance measures included compelling scientific evidence and clear consensus for use; requirements for the reporting process included interpretability, applicability, and feasibility.
Nine performance measures were refined and one was deleted. Four new performance measures were added and ten test measures were presented. Remember that performance measures are characterized as methods appropriate both for quality improvement and for external reporting, whereas test measures, which can be used for quality improvement, are not yet appropriate for external reporting, pending increased validation. Thus, the current set involves thirteen performance measures and nine test measures. The luxury of this presentation includes the provision of data collection instruments that display measurement specifications for each of these parameters, as presented in Appendix C. Adoption of this reporting format will enable serial comparisons within a hospital and comparisons among hospitals.
What Are the Important Revisions?
- Beta-blocker at arrival was deleted as a performance measure, based on data identifying the controversy regarding the magnitude of risk versus benefit and the complexity of recommendations regarding intravenous versus oral beta-blocker administration.
- Statin therapy at discharge, without requirement of a low-density lipoprotein-cholesterol (LDL-C) greater than 100 mg/dL. A class I guideline recommendation is that this be implemented regardless of baseline LDL-C and diet modification.
- LDL-C assessment was changed to a test measure because statin therapy is recommended at discharge irrespective of baseline LDL.
New Performance Measures
- Evaluation of left ventricular (LV) systolic function. This measure is a major determinant of prognosis and guides treatment decisions.
- For STEMI patients transferred for primary percutaneous intervention (PCI), the measurement of time from emergency department (ED) arrival at the STEMI referral facility to ED discharge to the PCI facility. This reflects the favorable impact of timely reperfusion on clinical outcomes.
- Time from ED arrival at the initial STEMI referral facility to arrival at the PCI- receiving facility (i.e., measure of time to PCI for transferred patients). This again reflects the major impact of timely reperfusion on clinical outcomes.
- Patient referral to cardiac rehabilitation from an inpatient setting. This incorporates the current guidelines for cardiac rehabilitation/secondary prevention for patients with AMI.
Commentary on the Rationale for the 2008 Performance Measures
Aspirin prescribed at arrival reduces mortality from MI and prescribed at discharge reduces both recurrent MI and death in survivors of MI. Beta-blockers prescribed at discharge reduce the risk of recurrent ischemic events and long-term mortality in patients surviving MI. Compelling scientific evidence for comparable benefit exists for statins prescribed at discharge. Evaluation of LV systolic function is important in that patients with LV systolic dysfunction (ejection fraction less than 40%) are candidates for specific therapies and in that its recognition may warrant prompt invasive management during the acute coronary syndrome hospitalization. Additionally, LV systolic dysfunction predicts long-term survival following MI. A prescription of an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker in such patients reduces the risk of vascular events and death in patients with established coronary artery disease.
Indicators of timely acute reperfusion therapy in STEMI patients reflect the greatest benefit in reducing mortality when such reperfusion is provided promptly after presentation; the rationale is comparable for the timeliness of PCI in patients who are transferred to another facility for the procedure. Issues include transfer time and the time to arrival for primary PCI at the PCI-transfer care facility. Acute reperfusion significantly reduces mortality, whether via fibrinolysis or primary PCI, mandating that transfer be performed in a timely manner, in that delayed PCI may not be as beneficial as timely fibrinolysis. Availability of this time-based information can inform the clinician's decision-making regarding the optimal mode of reperfusion for specific patients.
The educational component emphasized is smoking-cessation advice and counseling as necessary to recovery, long-term health, and prevention of subsequent reinfarction in survivors of MI. Also, cardiac rehabilitation referral from an inpatient setting is designed to optimize the appropriate referral of all AMI patients to outpatient cardiac rehabilitation programs. Effective referral is identified as the responsibility of the health care team.
- New test measures reflect National Registry data suggesting that excess anticoagulant/antiplatelet dosing is common in patients with acute coronary syndromes. Testing is designed to identify excessive initial heparin dose, excessive initial enoxaparin dose, excessive initial abciximab dose, excessive initial eptifibatide dose, and excessive initial tirofiban dose. As structural measures, anticoagulant dosing protocols and error tracking systems are recommended.
- Clopidogrel at discharge as a test measure is restricted to medically managed patients. Despite accumulating data on the benefit of dual antiplatelet therapy, this area of prescription has great variability in National Registry data. Rates of use of dual-antiplatelet therapy are already uniformly very high among patients following PCI and stent placement, such that measurement does not appear to be warranted.
Commentary on the Rationale for the 2008 Test Measures
LDL-C assessment has been changed from a performance to a test measure, in that this is needed to gauge the subsequent need for lipid-lowering therapy and/or dietary modification, but statin prescription at discharge should be independent of LDL-C. However, a known LDL less than 100 mg/dL constituted exclusion for routine statin therapy at discharge, owing to lack of consensus.
Five test measures relate to excessive initial dosing of unfractionated heparin, enoxaparin, abciximab, eptifibatide, and tirofiban, the most commonly used agents. National Registry data suggest that excess dosing is common in patients with acute coronary syndromes (unstable angina/non-STEMI) with potential negative consequences. Recommended doses for parenteral anticoagulant therapy and intravenous glycoprotein IIb/IIIa inhibitors are well established but may require knowledge of patient weight and/or estimation of glomerular filtration rate to guide dosing. An anticoagulant dosing protocol is recommended to avoid excess dosing and an anticoagulant error tracking system is recommended for the same reason.
A final test measure is that clopidogrel be prescribed at discharge for medically treated patients with AMI, given the sizeable variability of its use. Clopidogrel prescription after PCI and stenting is uniformly at a high level.
Facilitating Improved Delivery of Care and Patient Outcomes
Performance measures enable identification of current practices for patients with AMI within the hospital setting. Data regarding adherence to evidence-based recommendations are requisite for quality improvement, and quality improvement is requisite for improved patient outcomes. The measures selected for performance assessment have a strong scientific-evidence base, are simple and not costly to collect, and are characterized by the ability to collect data within a reasonable time period. Attributes of good performance measures are that they are evidence-based, that they are interpretable, and that they are actionable. The above performance measures fulfill these criteria.
Hospitalization for AMI can be viewed as the crisis intervention phase of coronary heart disease, whereas lifelong management is requisite for the ambulatory-care phase. Data are needed regarding other self-management skills introduced in the hospital, despite the abbreviated hospital stay for an acute event: diet, weight management, exercise, medication-taking, etc. Technologic advances enable this to be accomplished efficiently, with a continuum of education/information in the outpatient setting. Outcome data will guide clinical recommendations and performance measures.
Recent publication of the AHA Science Advisory on depression and coronary heart disease  should encourage brief questionnaire-based screening for this prevalent problem, with resultant referral and treatment. Again, outcome data will guide clinical recommendations and performance measures.
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2. Krumholz HM, Anderson JL, Bachelder BL, et al. ACC/AHA 2008 performance measures for adults with ST-elevation and non-ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association task force on performance measures (writing committee to develop performance measures for ST-elevation and non-ST-elevation myocardial infarction). Circulation 2008: published online before print November 10, 2008, 10.1161/CIRCULATIONAHA.108.191099.
3. Antman EM, Hand M, Armstrong PW, et al. 2007 Focused Update of the ACC/AHA 2004 Guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association task force on practice guidelines: developed in collaboration with the Canadian Cardiovascular Society endorsed by the American Academy of Family Physicians: 2007 writing group to review new evidence and update the ACC/AHA 2004 guidelines for the management of patients with ST-elevation myocardial infarction, writing on behalf of the 2004 writing committee. Circulation 2008;117:296-329.
4. Anderson JL, Adams CD, Antman EM, Bridges CR, et al. ACC/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association task force on practice guidelines (writing committee to revise the 2002 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction) developed in collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine. J Am Coll Cardiol 2007;50:e1-e157.
5. Thomas RJ, King M, Lui K, Oldridge N, Piña IL, Spertus J. AACVPR/ACC/AHA 2007 performance measures on cardiac rehabilitation for referral to and delivery of cardiac rehabilitation/secondary prevention services endorsed by the American College of Chest Physicians, American College of Sports Medicine, American Physical Therapy Association, Canadian Association of Cardiac Rehabilitation, European Association for Cardiovascular Prevention and Rehabilitation, Inter-American Heart Foundation, National Association of Clinical Nurse Specialists, Preventive Cardiovascular Nurses Association, and the Society of Thoracic Surgeons. J Am Coll Cardiol 2007;50:1400-1433.
6. Lichtman JH, Bigger JT, Jr., Blumenthal JA, et al. Depression and coronary heart disease: recommendations for screening, referral, and treatment: a science advisory from the American Heart Association Prevention Committee of the Council on Cardiovascular and Stroke Nursing, Council on Clinical Cardiology, Council on Epidemiology and Prevention, and Interdisciplinary Council on Quality of Care and Outcomes Research: endorsed by the American Psychiatric Association. Circulation 2008;118:1768-1775.
-- The opinions expressed in this commentary are not necessarily those of the editors or of the American Heart Association