Introduction
Quality of care has been a major focus of medical care since the Institute of Medicine focused attention on the unacceptable degree of variability in care and concern about patient safety and effectiveness. In its classic monograph, Crossing the Quality Chasm, the institute identified six aims to improve the quality of health care in the United States. It stressed that health care needs to provide safe, effective, patient-centric, timely, efficient, and equitable care. Efforts to achieve these goals have resulted in the growth and widespread use of a number of tools to improve care, including practice guidelines, appropriateness criteria, performance measures, and methods to put guidelines in practice. Of these tools, practice guidelines have provided the foundation for the other quality efforts. Cardiology has been at the forefront of this process due to a large number of clinical studies and randomized trials upon which to base the guideline recommendations.
Califf et al. has described the “cycle of quality” to emphasize the continuous evolution of quality of care. As shown in Figure 2-1 , discoveries of new or improved diagnostic tools and optimal treatments are suggested by basic and translational science. Initial observational clinical trials lead to more definitive randomized controlled trials. The evidence derived from these studies forms the basis for consensus-driven guideline recommendations. Guidelines provide the foundation for the patient-specific recommendations of appropriateness criteria where a number of key variables are integrated to best determine optimal use of procedures. Guidelines are also the basis for performance measures where clearly defined and validated variables can be used to monitor the degree of quality and reduce practice variability. New discoveries provide new directions or challenge prior practice and stimulate new clinical trials and the cycle repeats itself.
The explosion of guidelines over the past 20 years has been remarkable. Since 1995, the National Guideline Clearinghouse has identified 2352 practice guidelines, and of these, 491 are in the cardiovascular area ( www.guideline.gov ). The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) have published over 100 guidelines since 2005, and the European Society of Cardiology (ESC) has also been active in publishing similar guidelines. The ACCF/AHA have been leaders in publishing appropriateness criteria for cardiovascular tests and procedures. Other organizations, such as the AMA, in collaboration with the ACCF and AHA, have jointly published performance measures. In the cardiovascular field, the ACCF/AHA and ESC guidelines are the most respected and quoted documents.
Practice Guidelines
Guideline Development
The ACCF and AHA have adopted a strict and rigorous process for guideline development. The joint guideline committee identifies topics of interest and selects a writing committee composed of recognized experts in the field, seasoned clinicians, generalists, and other health care providers from associated disciplines, including nurses and pharmacists. Recent recommendations are to also include a patient advocate. The evidence from clinical registries and trials is collated, rigorously reviewed, and analyzed to assist the committee in formulating its recommendations. These recommendations are categorized into four classes: Class I is defined as procedures or treatment that SHOULD be performed or administered; Class II indications are those where it is REASONABLE to do the procedure/treatment (IIa) or where it MAY BE CONSIDERED (IIb); and Class III is defined as one that is anticipated to have NO BENEFIT or the procedure or treatment would cause HARM. The level of evidence for each recommendation is an important component of the process. Level A is used when the recommendation is supported by either multiple randomized trials or a metaanalysis; Level B is used when the recommendation is supported by either a single randomized trial or nonrandomized studies; and Level C is used when the recommendation is supported by either limited evidence, the consensus opinion of experts, or the standard of care. The final guidelines document is peer reviewed by external experts and revised before the final document is approved by the participating organizations. The process is lengthy, which limits the ability to quickly revise the guidelines as new information from clinical trials alters practice. Efforts to improve the process and increase the speed and rigor of guideline development have been described. While clinical trial data are critical to the formulation of guidelines, the lack of trials in many areas of practice unfortunately has resulted in Level C evidence (expert opinion), responsible for 48% of all guideline recommendations.
For the purposes of this chapter, only current ACCF/AHA guidelines are reviewed and only key recommendations that are directly pertinent to interventional cardiology practice are discussed. Please refer the original documents for a more detailed discussion of the guidelines and the evidence supporting the recommendations.
Guidelines for ST-Elevation Myocardial Infarction
The 2013 STEMI guidelines build upon the recommendations of the prior documents. This and past documents should be referred to for a more in-depth discussion of the recommendations and the evidence supporting them.
The guidelines recommend that the initial management of patients with an acute ST-segment myocardial infarction (STEMI) is the rapid reperfusion of the infarct artery. A reduction in the duration of the coronary occlusion results in a reduction in infarct size and mortality. Of the two reperfusion strategies, fibrinolysis or angioplasty, PCI is the preferred strategy when it can be performed expeditiously. The guidelines recommend that it should be accomplished within a time frame, from the first medical contact (FMC) to the first device, of less than 90 minutes and preferably within 60 minutes in patients who present within 12 hours of the onset of symptoms (Class IA) ( Figure 2-2 ). To achieve this goal, it is recommended that all communities create and maintain a regional system of care with integrated emergency medical services (EMS) and hospital systems that meet the guidelines for rapid diagnosis and triage (Class IB). Patients should be transferred by emergency medical systems (EMS) to PCI-capable hospitals for primary PCI. When patients present at a non-PCI-capable hospital, immediate transfer to a PCI-capable hospital should be done as rapidly as possible, with a goal of 120 minutes from the FMC to device use (Class Ib) and a door-in to door-out time at the first hospital of 30 minutes or less. When the FMC to device time is anticipated to be more than 120 minutes, a fibrinolytic agent should be given first, unless contraindicated. It is reasonable to then transfer the patient for PCI within 3 to 24 hours (the so-called pharmaco-invasive strategy) (Class IIa-b). When this strategy is chosen, the fibrinolytic agent should be administered within 30 minutes of hospital arrival. The guideline class (COR) and level of evidence (LOE) for these primary PCI strategies are shown in Figures 2-2, 2-3, 2-4, and 2-5 .
The management of patients with cardiogenic shock or severe heart failure is more aggressive with recommendations for PCI, regardless of the time after the onset of the symptoms or first contact. In this setting urgent transfer to a PCI-capable hospital is critical. Transfer for a failure of fibrinolytic therapy is also a reasonable strategy (so-called rescue angioplasty) (Class IIa-b). The guidelines for coronary angiography and potential PCI when a fibrinolytic agent is given or the patient received no reperfusion is shown in Figure 2-4 .
The national efforts to improve ischemic time (symptom onset to device/drug) have focused on the FMC to device time and particularly a key component of this time—the door to device time (D2D). Public reporting and efforts such as the AHA Mission Lifeline program and the ACCF D2B program have been successful in improving D2D times. The strategies to achieve this reduction have included prehospital ECG and activation of the cath lab while en route to the hospital, ED activation of the PCI team, a single page for activation of the cath lab, <20 minutes until cath lab staff arrive, and timely feedback to the STEMI care team. While these measures have been effective, the greatest delay in reperfusion is often the delay between the onset of symptoms to the 911 call or the hospital arrival. There are many reasons for this delay, and unfortunately, national efforts to reduce this time have not been successful.
Once the patient arrives at the cath lab, the interventional procedure should be performed expeditiously. Antiplatelet and anticoagulant therapy should be given as soon as possible upon initial medical contact. Dual antiplatelet therapy (aspirin and clopidogrel or prasugrel or ticagrelor) and an anticoagulant (UFH or bivalirudin) should be administered. GP IIb/IIIa agents (abciximab, tirofiban, or eptifibatide) are reasonable in combination with UFH (Class IIa). In current practice, the use of GP IIb/IIa agents has decreased due to concerns about increased bleeding risk, the introduction of the newer more potent P 2 Y 12 antiplatelet agents, and the greater use of bivalirudin. Based on randomized trials, the guideline committee felt it was not unreasonable to perform an aspiration thrombectomy (Class IIa-b). Recent trials have been mixed, and many operators have restricted the use to those situations where there is a large clot burden. Drug eluting stents (DES) or bare metal stents (BMS) should be used when possible (Class Ia). Most operators have favored DES, given evidence from large randomized trials of improved long-term outcomes, particularly the reduction in target vessel revascularization without an increased risk of stent thrombosis. BMS should be used when there is an increased risk of bleeding or a concern about compliance with dual antiplatelet therapy for 1 year (Class IC). Initial primary PCI should be restricted to the infarct-related artery, and current guidelines recommend against treatment of other significant stenosis at the same setting. Multivessel PCI is indicated in patients who develop spontaneous symptoms of ischemia (Class Ic) and those patients with an intermediate to high risk of noninvasive testing prior to discharge (Class IIa). These recommendations have been recently challenged following the results of the PRAMI trial that demonstrate improved outcomes with multivessel PCI at the same setting as the primary PCI. A number of large randomized trials are ongoing to help address this issue.
Coronary artery bypass surgery is indicated for patients not amenable to PCI and those who have ongoing or recurrent ischemia, cardiogenic shock, severe heart failure, or other high-risk features (Class Ib). CABG is rarely used as the primary reperfusion strategy, but it is commonly used for other indications during hospitalization, particularly in patients who have extensive coronary disease or have disease that is not amenable to PCI.
The subsequent medical management with dual antiplatelet therapy, oral anticoagulants, beta-blockers, ACE or ARB agents, and statins, in addition to risk factor modification and cardiac rehabilitation, are critically important in improving long-term outcomes and preventing future events. The reader should refer to the STEMI guidelines for specific recommendations.
Guidelines for Unstable Angina/Non–ST-Elevation MI
The ACCF/AHA guidelines for unstable angina and non–ST-elevation MI (UA/NSTEMI) were released in 2007; since then two focused updates have been published, the most recent in 2012. This report provides an update on the use of antiplatelet and anticoagulant therapy and management of special groups such as patients with diabetes and chronic kidney disease.
An overview of the guideline recommendations for the management of UA/NSTEMI is shown in Figure 2-6 . The initial assessment of the patient is to determine the likelihood of acute coronary syndrome based on the history, physical examination, EKG, laboratory tests, cardiac biomarkers, and risk factors. In those in whom the diagnosis is likely or definite, the guidelines recommend that the patient’s risk be assessed using one of the available risk scores such as Thrombolysis in Myocardial Infarction (TIMI) or Global Registry of Acute Coronary Events (GRACE) (Class IIa-b). Patients at low risk and/or low likelihood of ACS can be managed in a chest pain unit or in the hospital for 24 hours with serial EKGs and cardiac-specific enzymes. If these tests do not show evidence of ischemia or infarction, the patient should be further risk stratified with a noninvasive test such as a treadmill exercise test (ETT), a nuclear imaging stress test, or a coronary CT angiogram. If these tests are negative or demonstrate a low risk of subsequent events, the patient can be discharged and followed as an outpatient. If the noninvasive test is positive and suggests an increased risk of cardiac events, the patient should be referred for urgent diagnostic cardiac catheterization.
Intermediate- or high-risk patients should be admitted to the hospital for observation, more aggressive medical therapy, and possible cardiac catheterization. It is important to note that cardiac enzyme elevation alone does not automatically imply high risk and can be due to causes other than a myocardial infarction, and likewise, a patient can be high risk without elevation of cardiac enzymes.
The decision to proceed with an initial invasive versus conservative strategy is influenced by the risk of the patient, with higher risk patients best treated with an invasive strategy. The guideline recommendations for selecting the appropriate strategy, early invasive versus initial conservative, are shown in Table 2-1 . The timing of an early invasive strategy has been tested in three trials. The largest, the TIMAC trial, failed to reach its primary endpoint but strongly suggested that an invasive strategy should be performed within 12 to 24 hours, particularly in those patients at highest risk, as determined by the GRACE score (Class IIa-b).
| GENERALLY PREFERRED STRATEGY | PATIENT CHARACTERISTICS |
|---|---|
| Invasive |
|
| Conservative |
|
All patients should be given anticoagulant therapy in addition to antiangina medication. The Class I indications for antiplatelet agents are shown in Figure 2-6 and Table 2-2 . It is recommended that aspirin be given as soon as possible (or clopidogrel if the patient is allergic to aspirin) (Class Ia). Those at moderate to high risk or in whom an initial invasive strategy has been chosen should be given dual antiplatelet therapy on presentation (Class Ia) with a loading and maintenance dose of either clopidogrel or ticagrelor or an IV GP IIb/IIIa inhibitor prior to PCI. If not given before PCI, clopidogrel, ticagrelor, and prasugrel or IC GP IIb/IIIa inhibitors can be given at the time of the PCI procedure. The use of GP IIb/IIIa inhibitors in practice has diminished with the availability of potent oral antiplatelet agents and increased bleeding risk of these agents. The guidelines favor their use in those who have recurrent ischemic pain. Studies have shown that upstream use of GP IIb/IIIa inhibitors is not useful. If bivalirudin is used as the anticoagulant, it is reasonable to omit a GP IIb/IIIa inhibitor given the lack of greater efficacy and increased bleeding risk. The recommended anticoagulants (Class I) are unfractionated heparin, enoxaparin, fondaparinux, and bivalirudin. Fondaparinux and enoxaparin are favored for those patients who are managed with a conservative strategy and are not likely to undergo an invasive procedure. If fondaparinux is used, unfractionated heparin should be given in addition if the patient undergoes a PCI due to an increased risk of catheter thrombosis.
| 2012 FOCUSED UPDATE RECOMMENDATIONS |
|---|
| Class I |
|
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