Key Points
- •
Therapeutic options for treatment of patients to prevent cardiovascular disease events have increased at an exponential rate during the past quarter century.
- •
The Institute of Medicine has emphasized that treatment strategies and recommendations must be founded on a strong evidence base.
- •
Comprehensive scientific guidelines, performance measures, and policies supporting preventive therapies will rely on this foundation of scientific information.
- •
Evolving data confirm the efficacy of evidence-based medicine to improve patient outcomes.
- •
It is imperative that health care providers shape their practices to keep abreast of the concepts put forth in the cardiovascular disease guidelines and performance measures.
The therapeutic options for treatment of patients to prevent cardiovascular disease (CVD) events have increased at an exponential rate during the past quarter century. This increase in medical therapies, procedures, and tests coupled with growing numbers of patients at risk for CVD events or surviving after an event has resulted in a wide array of treatment strategies, often leaving the health care provider uncertain about the appropriate course of action. Mounting evidence during the past decade has documented significant variation in the performance of recommended tests and therapies and patient outcomes. On the basis of these trends and observations, the Institute of Medicine recommended in its 2001 report Crossing the Quality Chasm: A New Health System for the 21st Century, “Patients should receive care based on the best available scientific knowledge. Care should not vary illogically from clinician to clinician or from place to place.” The cardiovascular community has responded by the development of evidence-based practice guidelines and performance measures with the intent of providing consistent high-quality care and outcomes for patients with CVD.
Clinical Practice Guidelines: Background
Current strategies for prevention or treatment of CVD are increasingly based on guideline recommendations. Among such guideline statements, those issued by the American College of Cardiology (ACC) and the American Heart Association (AHA) have gained widespread recognition and use. The origins of the ACC/AHA practice guidelines date to the early 1980s, when the federal government requested the recommendations of the ACC and AHA on the indications for cardiac pacemakers. In the early years of the guideline efforts, several statements were developed for a variety of procedures and diagnostic tests, including coronary bypass graft surgery, exercise treadmill testing, percutaneous coronary interventions, and radionuclide testing. Understanding that physicians providing patient care need information on the treatment and management of a complete disease state rather than isolated advice about when to perform a procedure or diagnostic test, the ACC/AHA practice guidelines have evolved to a focus on disease states such as ST-segment elevation myocardial infarction (STEMI), valvular heart disease, chronic stable angina, and heart failure. This has resulted in an increasing number of recommendations supported by varying levels of evidence and expert consensus opinion.
Guideline Recommendations and Evidence
The definitions used by the ACC/AHA guideline statements for the classification of recommendations and supporting level of evidence are shown in Figure 36-1 . The recommendations range from Class I, for which the benefit of a test, treatment, or procedure greatly exceeds the risk and it is recommended that the test, treatment, or procedure be done, to Class III, for which the benefit of a test, treatment, or procedure is less than or equivalent to the risk and therefore should not be done. Situated between these strong recommendations in favor for or against performing a test, procedure, or treatment are Class IIa and IIb recommendations, for which benefit exceeds risk such that the performance of the test, procedure, or treatment is deemed reasonable (IIa) or might be considered (IIb). For each class of recommendation, the guidelines must further state the level of evidence on which the recommendation is based. Level A represents multiple randomized clinical trials or meta-analyses obtained in multiple subgroups including age, gender, and ethnicity; level B represents data from single randomized trials or nonrandomized studies in which limited populations have been evaluated; and level C is based on consensus opinion of experts, case studies, or standards of care. A level of evidence of B or C does not necessarily imply a weak recommendation. There are many important clinical questions for which the number of patients available for a randomized controlled trial is too small to provide significant results or the clinical circumstances are such that there is a clear and strong consensus regarding the indication for a test, procedure, or treatment. However, the guidelines are written with the objective of having the strongest evidence base possible.
During recent years, considerable efforts have been directed toward avoiding conflicts of interest and relationships with industry that might potentially bias the recommendations in guideline statements. The ACC and AHA have instituted strong policies to see that such interests are avoided in the development of guideline statements. Members of guideline writing committees must recuse themselves from voting when such conflicts or relationships are present, and their recusal is noted in the guideline statement. Membership of the guideline writing groups is being structured with a goal that no more than 30% of the writing group may have conflicts of interest or relationships with industry for the tests, procedures, and treatments being discussed. Further review and recommendations for approval of all ACC/AHA guidelines are provided by additional individuals, including members of the Science Advisory Committee of the AHA, Board of Trustees of the ACC, expert content reviewers, and representatives from other societies participating in the development or endorsement of the guideline. These measures help ensure that the guidelines are strongly based on evidence or objective expert consensus.
Guideline Recommendations and Evidence
The definitions used by the ACC/AHA guideline statements for the classification of recommendations and supporting level of evidence are shown in Figure 36-1 . The recommendations range from Class I, for which the benefit of a test, treatment, or procedure greatly exceeds the risk and it is recommended that the test, treatment, or procedure be done, to Class III, for which the benefit of a test, treatment, or procedure is less than or equivalent to the risk and therefore should not be done. Situated between these strong recommendations in favor for or against performing a test, procedure, or treatment are Class IIa and IIb recommendations, for which benefit exceeds risk such that the performance of the test, procedure, or treatment is deemed reasonable (IIa) or might be considered (IIb). For each class of recommendation, the guidelines must further state the level of evidence on which the recommendation is based. Level A represents multiple randomized clinical trials or meta-analyses obtained in multiple subgroups including age, gender, and ethnicity; level B represents data from single randomized trials or nonrandomized studies in which limited populations have been evaluated; and level C is based on consensus opinion of experts, case studies, or standards of care. A level of evidence of B or C does not necessarily imply a weak recommendation. There are many important clinical questions for which the number of patients available for a randomized controlled trial is too small to provide significant results or the clinical circumstances are such that there is a clear and strong consensus regarding the indication for a test, procedure, or treatment. However, the guidelines are written with the objective of having the strongest evidence base possible.
During recent years, considerable efforts have been directed toward avoiding conflicts of interest and relationships with industry that might potentially bias the recommendations in guideline statements. The ACC and AHA have instituted strong policies to see that such interests are avoided in the development of guideline statements. Members of guideline writing committees must recuse themselves from voting when such conflicts or relationships are present, and their recusal is noted in the guideline statement. Membership of the guideline writing groups is being structured with a goal that no more than 30% of the writing group may have conflicts of interest or relationships with industry for the tests, procedures, and treatments being discussed. Further review and recommendations for approval of all ACC/AHA guidelines are provided by additional individuals, including members of the Science Advisory Committee of the AHA, Board of Trustees of the ACC, expert content reviewers, and representatives from other societies participating in the development or endorsement of the guideline. These measures help ensure that the guidelines are strongly based on evidence or objective expert consensus.
Status of Current Guideline Evidence Base
The largest continuous experience with the development of cardiovascular guidelines is found in the joint efforts of the ACC and AHA. These guidelines have provided critical information to assist with the establishment of standards of care and benchmarks to assess quality of care. The evolution of recommendations in these guidelines and the development of evidence base for these recommendations have been analyzed and provide insight into challenges facing development of current guideline statements. Since the first ACC/AHA clinical practice guideline was released in 1984 on the indications for cardiac pacemakers to September 2008, the ACC/AHA Task Force on practice guidelines has published 53 guidelines on 22 topics resulting in a total of 7196 recommendations. Among these 53 guidelines, there were 22 that were diseased based, 15 that were interventional procedure based, and 14 that were diagnostic procedure based. The use of level of evidence for guideline recommendations was first introduced in 1998, and analysis of the 16 guidelines current at the time of the report comprising a total of 2711 recommendations revealed a high proportion of recommendations (48%) to be based on expert consensus, standard of care, or case studies (level of evidence C), whereas a small number (11%) were derived from a high evidence base of multiple randomized controlled trials or meta-analyses (level of evidence A). Moreover, among those guidelines that had undergone one revision or update, there was a 48% increase in recommendations, with the greatest number occurring in Class II, indicating a level of uncertainty in the recommendation. Importantly, the secondary prevention guideline recommendations had the highest evidence base, with more than 90% being level of evidence A or B, attesting to the strong evidence available to support recommendations for preventive therapies.
Future Considerations for Guideline Development
The observations from the review of ACC/AHA guidelines support the need for more evidence to assist with the clinical decisions faced by physicians who treat patients with CVD. The current system of clinical research that generates evidence from randomized controlled trials is largely supported by the pharmaceutical industry and in most instances is understandably directed toward gaining approval of new medical therapies. There is limited sponsorship of trials that focus on questions relating to clinical practice combining or comparing existing tests, procedures, and treatments. Broader support and funding are necessary if we are to advance the knowledge base for guideline development.
The purpose of the ACC/AHA practice guidelines is to assist health care providers in clinical decision making by describing a range of reasonably acceptable approaches to assist in the diagnosis, management, and prevention of cardiovascular diseases or conditions. Guideline recommendations attempt to define practices that will meet the needs of most patients in most circumstances. However, the ultimate judgment regarding care of a particular patient should be made by the health care provider and patient, with all of the circumstances presented by that patient taken into consideration. Thus, there are circumstances in which deviations from these guidelines may be appropriate, especially when a recommendation is of lower certainty, such as Class IIb, and supported primarily by expert opinion level C. Clinical decision making should also consider the quality and availability of expertise in the area where care is provided. On occasion, the ACC/AHA guidelines may be used as the basis for regulatory or payer decisions, but their ultimate goal is to improve quality of care and to serve the patient’s best interests.
Guidelines for Secondary Prevention
The AHA/ACC Guidelines for Secondary Prevention, endorsed by the National Heart, Lung, and Blood Institute (NHLBI), provide concise evidence-based recommendations for the prevention of cardiovascular events in patients with established CVD. The goal for controlling each risk factor is listed in conjunction with recommended therapeutic interventions to achieve that goal ( Table 36-1 ). The class of recommendation and evidence base for each intervention are concisely summarized, and the references and supplemental search criteria are provided. As noted earlier in this chapter, these guidelines have a high evidence base, with more than 90% being level A or B. They are widely used and quoted and provide the basis for the AHA and ACC quality improvement programs reviewed later in this chapter.
| Intervention Recommendations with Class of Recommendation and Level of Evidence | |
|---|---|
| Smoking |
|
| Goal | |
| Complete cessation. No exposure to environmental tobacco smoke. | |
| • Urge avoidance of exposure to environmental tobacco smoke at work and home. I (B) | |
| Blood Pressure Control | For all patients: |
| Goal | • Initiate or maintain lifestyle modification—weight control; increased physical activity; alcohol moderation; sodium reduction; and emphasis on increased consumption of fresh fruits, vegetables, and low-fat dairy products. I (B) |
| <140/90 mm Hg or <130/80 mm Hg if patient has diabetes or chronic kidney disease | |
| For patients with blood pressure ≥140/90 mm Hg (or ≥130/80 mm Hg for individuals with chronic kidney disease or diabetes): | |
| • As tolerated, add blood pressure medication, treating initially with beta blockers and/or ACE inhibitors, with addition of other drugs such as thiazides as needed to achieve goal blood pressure . I (A) | |
| [For compelling indications for individual drug classes in specific vascular diseases, see Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7).] | |
| Lipid Management Goal LDL-C <100 mg/dL If triglycerides are ≥200 mg/dL, non–HDL-C should be <130 mg/dL † | For all patients: |
| • Start dietary therapy. Reduce intake of saturated fats (to <7% of total calories), trans –fatty acids, and cholesterol (to <200 mg/d). I (B) | |
| • Adding plant stanol/sterols (2 g/d) and viscous fiber (>10 g/d) will further lower LDL-C. | |
| • Promote daily physical activity and weight management. I (B) | |
| • Encourage increased consumption of omega-3 fatty acids in the form of fish ‡ or in capsule form (1 g/d) for risk reduction. For treatment of elevated triglycerides, higher doses are usually necessary for risk reduction. IIb (B) | |
| For lipid management: | |
| Assess fasting lipid profile in all patients, and within 24 hours of hospitalization for those with an acute cardiovascular or coronary event. For hospitalized patients, initiate lipid-lowering medication as recommended below before discharge according to the following schedule: | |
| • LDL-C should be <100 mg/dL I (A) , and | |
| • Further reduction of LDL-C to <70 mg/dL is reasonable. IIa (A) | |
| • If baseline LDL-C is ≥100 mg/dL, initiate LDL-lowering drug therapy. § I (A) | |
| • If on-treatment LDL-C is ≥100 mg/dL, intensify LDL-lowering drug therapy (may require LDL-lowering drug combination || ). I (A) | |
| • If baseline LDL-C is 70 to 100 mg/dL, it is reasonable to treat to LDL-C <70 mg/dL. IIa (B) | |
| • If triglycerides are 200 to 499 mg/dL, non–HDL-C should be <130 mg/dL. I (B) , and | |
| • Further reduction of non–HDL-C to <100 mg/dL is reasonable. IIa (B) | |
| • Therapeutic options to reduce non–HDL-C are: | |
| • More intense LDL-C–lowering therapy I (B) , or | |
| • Niacin ¶ (after LDL-C–lowering therapy) IIa (B) , or | |
| • Fibrate therapy # (after LDL-C–lowering therapy) IIa (B) | |
| • If triglycerides are ≥500 mg/dL, # therapeutic options to prevent pancreatitis are fibrate ¶ or niacin ¶ before LDL-lowering therapy; and treat LDL-C to goal after triglyceride-lowering therapy. Achieve non–HDL-C <130 mg/dL if possible. I (C) | |
| Physical Activity | • For all patients, assess risk with a physical activity history and/or an exercise test, to guide prescription. I (B) |
| Goal | • For all patients, encourage 30 to 60 minutes of moderate-intensity aerobic activity, such as brisk walking, on most, preferably all, days of the week, supplemented by an increase in daily lifestyle activities (e.g., walking breaks at work, gardening, household work). I (B) |
| 30 minutes, 7 days per week (minimum 5 days per week) | |
| • Encourage resistance training 2 days per week. IIb (C) | |
| • Advise medically supervised programs for high-risk patients (e.g., recent acute coronary syndrome or revascularization, heart failure). I (B) | |
| Weight Management | • Assess body mass index and/or waist circumference on each visit and consistently encourage weight maintenance/reduction through an appropriate balance of physical activity, caloric intake, and formal behavioral programs when indicated to maintain/achieve a body mass index between 18.5 and 24.9 kg/m 2 . I (B) |
| Goal | |
| Body mass index: 18.5 to 24.9 kg/m 2 | |
| Waist circumference: men <40 inches, women <35 inches | • If waist circumference (measured horizontally at the iliac crest) is ≥35 inches in women and ≥40 inches in men, initiate lifestyle changes and consider treatment strategies for metabolic syndrome as indicated. I (B) |
| • The initial goal of weight loss therapy should be to reduce body weight by approximately 10% from baseline. With success, further weight loss can be attempted if indicated through further assessment. I (B) | |
| Diabetes Management | • Initiate lifestyle and pharmacotherapy to achieve near-normal HbA1c. I (B) |
| Goal | • Begin vigorous modification of other risk factors (e.g., physical activity, weight management, blood pressure control, and cholesterol management as recommended above). I (B) |
| HbA1c <7% | |
| • Coordinate diabetic care with patient’s primary care physician or endocrinologist. I (C) | |
| Antiplatelet Agents/Anticoagulants | • Start aspirin 75 to 162 mg/d and continue indefinitely in all patients unless contraindicated. I (A) |
| • For patients undergoing coronary artery bypass grafting, aspirin should be started within 48 hours after surgery to reduce saphenous vein graft closure. Dosing regimens ranging from 100 to 325 mg/d appear to be efficacious. Doses higher than 162 mg/d can be continued for up to 1 year. I (B) | |
| • Start and continue clopidogrel 75 mg/d in combination with aspirin for up to 12 months in patients after acute coronary syndrome or percutaneous coronary intervention with stent placement (≥1 month for bare metal stent, ≥3 months for sirolimus-eluting stent, and ≥6 months for paclitaxel-eluting stent). I (B) | |
| • Patients who have undergone percutaneous coronary intervention with stent placement should initially receive higher-dose aspirin at 325 mg/d for 1 month for bare metal stent, 3 months for sirolimus-eluting stent, and 6 months for paclitaxel-eluting stent. I (B) | |
| • Manage warfarin to international normalized ratio = 2.0 to 3.0 for paroxysmal or chronic atrial fibrillation or flutter, and in post–myocardial infarction patients when clinically indicated (e.g., atrial fibrillation, left ventricular thrombus). I (A) | |
| • Use of warfarin in conjunction with aspirin and/or clopidogrel is associated with increased risk of bleeding and should be monitored closely. I (B) | |
| Renin-Angiotensin-Aldosterone System Blockers | ACE inhibitors: |
| • Start and continue indefinitely in all patients with left ventricular ejection fraction ≤40% and in those with hypertension, diabetes, or chronic kidney disease, unless contraindicated. I (A) | |
| • Consider for all other patients. I (B) | |
| • Among lower-risk patients with normal left ventricular ejection fraction in whom cardiovascular risk factors are well controlled and revascularization has been performed, use of ACE inhibitors may be considered optional. IIa (B) | |
| Angiotensin receptor blockers: | |
| • Use in patients who are intolerant of ACE inhibitors and have heart failure or have had a myocardial infarction with left ventricular ejection fraction ≤40%. I (A) | |
| • Consider in other patients who are ACE inhibitor intolerant. I (B) | |
| • Consider use in combination with ACE inhibitors in systolic-dysfunction heart failure. IIb (B) | |
| Aldosterone blockade: | |
| • Use in post–myocardial infarction patients, without significant renal dysfunction ** or hyperkalemia, †† who are already receiving therapeutic doses of an ACE inhibitor and beta blocker, have a left ventricular ejection fraction ≤40%, and have either diabetes or heart failure. I (A) | |
| Beta Blockers | • Start and continue indefinitely in all patients who have had myocardial infarction, acute coronary syndrome, or left ventricular dysfunction with or without heart failure symptoms, unless contraindicated. I (A) |
| Consider chronic therapy for all other patients with coronary or other vascular disease or diabetes unless contraindicated. IIa (C) | |
| Influenza Vaccination | Patients with cardiovascular disease should have an influenza vaccination. I (B) |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
