Robert L. McNamara

ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary

Atrial fibrillation (AF), the most common sustained cardiac rhythm disturbance, is increasing in prevalence as the population ages. Although it is often associated with heart disease, AF occurs in many patients with no detectable disease. Hemodynamic impairment and thromboembolic events result in significant morbidity, mortality, and cost. Accordingly, the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology (ESC) created a committee of experts to establish guidelines for management of this arrhythmia. The committee was composed of 8 members representing the ACC and AHA, 4 representing the ESC, 1 from the North American Society of Pacing and Electrophysiology (NASPE), and a representative of the Johns Hopkins University Evidence-Based Practice Center representing the Agency for Healthcare Research and Quality’s report on Atrial Fibrillation in the Elderly. This document was reviewed by 3 official reviewers nominated by the ACC, 3 nominated by the AHA, and 3 nominated by the ESC, as well as by the ACC Clinical Electrophysiology Committee, the AHA ECG and Arrhythmia Committee, NASPE, and 25 reviewers nominated by the writing committee. The document was approved for publication by the governing bodies of the ACC, AHA, and ESC and officially endorsed by NASPE. These guidelines will be reviewed annually by the task force and will be considered current unless the task force revises or withdraws them from distribution. The committee conducted a comprehensive review of the literature from 1980 to June 2000 relevant to AF using the following databases: PubMed/Medline, EMBASE, the Cochrane Library (including the Cochrane Database of Systematic Reviews and the Cochrane Controlled Trials Registry), and Best Evidence. Searches were limited to English language sources and to human subjects. ### A. Atrial Fibrillation AF is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation with consequent deterioration of atrial mechanical function. On the electrocardiogram (ECG), AF …Atrial fibrillation (AF), the most common sustained cardiac rhythm disturbance, is increasing in prevalence as the population ages. Although it is often associated with heart disease, AF occurs in many patients with no detectable disease. Hemodynamic impairment and thromboembolic events result in

Achieving Rapid Door-To-Balloon Times. How Top Hospitals Improve Complex Clinical Systems

Background— Fewer than half of patients with ST-elevation acute myocardial infarction (STEMI) are treated within guideline-recommended door-to-balloon times; however, little information is available about the approaches used by hospitals that have been successful in improving door-to-balloon times to meet guidelines. We sought to characterize experiences of hospitals with outstanding improvement in door-to-balloon time during 1999–2002. Methods and Results— We performed a qualitative study using in-depth interviews (n=122) with clinical and administrative staff at 11 hospitals that were participating with the National Registry of Myocardial Infarction and had median door-to-balloon times of ≤90 minutes during 2001–2002, representing substantial improvement since 1999. Data were organized with the use of NUD-IST 4 (Sage Publications Software) and were analyzed by the constant comparative method of qualitative data analysis. Eight themes characterized hospitals’ experiences: commitment to an explicit goal to improve door-to-balloon time motivated by internal and external pressures; senior management support; innovative protocols; flexibility in refining standardized protocols; uncompromising individual clinical leaders; collaborative teams; data feedback to monitor progress and identify problems and successes; and an organizational culture that fostered resilience to challenges or setbacks in improvement efforts. Conclusions— Several themes characterized the experiences of hospitals that had achieved notable improvements in their door-to-balloon times. By distilling the complex and diverse experiences of organizational change into its essential components, this study provides a foundation for future efforts to elevate clinical performance in the hospital setting.

Management of Atrial Fibrillation: Review of the Evidence for the Role of Pharmacologic Therapy, Electrical Cardioversion, and Echocardiography

Atrial fibrillation is the most common type of arrhythmia in adults, accounting for about one third of hospitalizations for arrhythmia (1). The prevalence increases from less than 1% in persons younger than 60 years of age to more than 8% in those older than 80 years of age (2-6). The incidence ranges from 0.2% per year for men 30 to 39 years of age to 2.3% per year in men 80 to 89 years of age (7, 8). The age-adjusted incidence for women is about half that of men (9). The cardiac conditions most commonly associated with atrial fibrillation are rheumatic mitral valve disease, coronary artery disease, congestive heart failure, and hypertension (8, 10). Noncardiac causes include hyperthyroidism, hypoxic conditions, surgery, and alcohol intoxication. A predisposing condition exists in more than 90% of cases (5, 11, 12); the remaining cases have what is called lone atrial fibrillation. Patients with atrial fibrillation frequently have symptoms of hemodynamic compromise, ranging from irregular palpitations to the more insidious feeling of malaise. They also have an increased risk for thromboembolism. Comparing with age-matched controls, the relative risk for stroke is increased 2- to 7-fold in patients with nonrheumatic atrial fibrillation (3, 8, 13), and the absolute risk for stroke is between 1% and 5% per year, depending on clinical characteristics (3, 12, 14-16). Quality of life is an important consideration for patients. Paroxysmal atrial fibrillation disrupts the lives of patients (17), but this perception may not be associated with frequency or duration of symptoms. Warfarin therapy affects quality of life because of frequent blood testing and recommendations for limiting some activities. Gage and colleagues (18) found that atrial fibrillation decreases utility, a quantitative assessment of quality of life used in decision analysis, by 1.3%. Protheroe and associates (19) found that only 61% of patients would prefer anticoagulation to no treatment, considerably fewer than those for whom guidelines would recommend treatment. Little is known about the direct effects of antiarrhythmic therapy and rate-control therapy on quality of life. The American College of Cardiology/American Heart Association/European Society of Cardiology Task Force on Clinical Guidelines for the Management of Atrial Fibrillation classified atrial fibrillation into 4 types (20): first detected episode, paroxysmal (terminates spontaneously), persistent (electrical or pharmacologic termination necessary), and permanent (resistant to electrical or pharmacologic conversion or accepted by the physician). The purpose of this review was to summarize the evidence that was available during formulation of the guidelines developed by the American College of Physicians (ACP) and the American Academy of Family Physicians (AAFP) for management of adult patients with nonpostoperative atrial fibrillation. The foundation of this background paper was a systematic review of the pharmacologic management of atrial fibrillation that examined the efficacy of medications used for stroke prevention, ventricular rate control, acute conversion, and maintenance of sinus rhythm, as well as the role of echocardiography in guiding pharmacologic therapy (21). For this updated version of the systematic review, we considered observational data, consensus statements, decision analyses, and relevant guidelines. This review focused on the evaluation and pharmacologic management of adult patients with nonpostoperative atrial fibrillation. The rapidly advancing field of nonpharmacologic management of atrial fibrillation is outside the scope of this paper. Methods A full description of the methods used in the systematic review can be found in a detailed evidence report (21). A brief description of these methods and additional methods specific to this article are given below. Literature Identification Whenever possible, we focused our searches for relevant evidence on the strongest study design: randomized, controlled trials (RCTs). For our previous systematic review, we identified controlled trials in the CENTRAL database produced by the Cochrane Collaborations international efforts, searched MEDLINE from 1966 to 1998 for citations tagged as randomized, controlled trial or controlled clinical trial, searched the PubMed Related Articles feature, reviewed hand searches submitted to the Baltimore Cochrane Center, scanned the reference lists in relevant publications, and scanned the table of contents of relevant journals. For the current review, we also searched MEDLINE from May 1998 through September 2001 (using the same search terms as in the original review plus terms to identify meta-analyses and decision analyses). For topics without sufficient RCTs, we used observational data, consensus statements, review articles, and decision analyses obtained from our search of MEDLINE from 1966 through September 2001. Although we had to use September 2001 as a cutoff for the systematic searching of the literature in order to generate a report for the ACPAAFP Guideline group, we included selected studies published after September 2001 on the basis of input from the group. Article Review Process Studies were eligible for review if they were randomized trials of adult patients that addressed the management of nonpostoperative atrial fibrillation. In the previous systematic review, 521 citations were identified and 179 articles were eligible for detailed review. The updated search yielded 29 additional articles that met our inclusion criteria. Statistical Analysis For the quantitative analysis, we stratified the data to obtain an effect measure for each drug. We used Stata, version 7.0 (Stata Corp., College Station, Texas) to calculate the odds ratio (OR) of success of the drug compared with placebo. Respective 95% CIs and P values were also calculated. We used ORs because they provide less heterogeneity of study results than relative risk ratio. Estimates of the relative rates of the outcomes of interest were pooled by using standard methods for combining the OR for the outcomes of conversion to sinus rhythm, maintenance of sinus rhythm, stroke, peripheral embolism, major bleeding, minor bleeding, and death (21). Studies were weighted on the basis of the precision of the estimate within each study. When no heterogeneity was found, meta-analyses used the fixed-effects model (MantelHaenszel method for pooling) (22). When heterogeneity was found, the random-effects model was used (DerSimonian and Laird method of pooling) (23). An OR was considered significantly different from 1 if the P value was less than 0.05. Statistical strength of evidence was categorized as strong (P 0.01), moderate (0.01 < P 0.05), suggestive (0.05 < P 0.2), or inconclusive (P > 0.2). Role of the Funding Sources The initial systematic review was funded through a contract with the Agency for Healthcare Research and Quality (21). Subsequent work was supported by the American College of Physicians. Drafts of the manuscript were reviewed by members of the ACP/AAFP guidelines committee for management of atrial fibrillation. Data Synthesis Does Aggressive Rhythm Control Improve Mortality and Morbidity Compared with Rate Control? Although the relative benefits and risks of rate versus rhythm control are of paramount importance in the management of atrial fibrillation, studies directly addressed this issue only recently. By far the largest, the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial was a multicenter RCT that enrolled 4060 patients from more than 200 sites in Canada and the United States (24). Eligibility criteria included documented atrial fibrillation lasting at least 6 hours and at least 1 risk factor for stroke (age >65 years, hypertension, diabetes mellitus, previous stroke, and poor ventricular function). Average age was 70 years. Sixty-one percent of patients were men, 89% were white, 71% had hypertension, 38% had coronary artery disease, and 18% had had failure of antiarrhythmic therapy. After patients were randomly assigned to the rhythm-control or rate-control group, physicians could choose from a list of pharmacologic and nonpharmacologic therapies. Although anticoagulation was continued indefinitely for the rate-control group, discontinuation of anticoagulation was permitted at 1 month or later following conversion in the rhythm-control arm. The mortality rate at 5 years was 23.8% in the rhythm-control group and 21.3% in the rate-control group (hazard ratio, 1.15 [95% CI, 0.99 to 1.34]; P = 0.08). Combined central nervous system ischemic strokes and hemorrhagic events occurred in 8.9% of patients in the rhythm-control group and 7.4% of patients in the rate-control group (P > 0.2). Eighty-five patients in the rhythm-control group and 79 in the rate-control group had strokes (P > 0.2). Of note, more than 70% of the strokes in both groups occurred in patients who had stopped taking anticoagulant therapy or who had an international normalized ratio less than 2.0. Preliminary analyses of other secondary end points, including quality of life and functional capacity, did not show statistical difference between treatment groups. However, more hospitalizations occurred in the rhythm-control group. A smaller study conducted in the Netherlands, the RAte Control versus Electrical cardioversion for persistent atrial fibrillation (RACE) study (25), randomly assigned 522 patients to aggressive rhythm control or rate control only. Mean age was 68 years. Sixty-four percent were men, 49% had hypertension, and 27% had coronary artery disease. The primary composite end point of cardiovascular mortality, heart failure, thromboembolic complications, bleeding, pacemaker implantation, and severe side effects of antiarrhythmic drugs occurred in 17.2% of patients in the rate-control group and in 22.6% of patients in the rhythm-control group over a mean of 2.3 years. Thus, rate control was not inferior

ACC/AHA/Physician Consortium 2008 Clinical Performance Measures for Adults With Nonvalvular Atrial Fibrillation or Atrial Flutter: A Report of the American College of Cardiology/American Heart Association Task Force on Performance Measures and the Physician Consortium for Performance Improvement (Writing Committee to Develop Clinical Performance Measures for Atrial Fibrillation) Developed in Collaboration With the Heart Rhythm Society

Robert O. Bonow, MD, FACC, FAHA, Chair; N.A. Mark Estes III, MD, FACC, FAHA, FHRS; Elizabeth DeLong, PhD; David C. Goff, Jr, MD, PhD, FAHA, FACP; Kathleen Grady, PhD, RN, FAHA, FAAN; Lee A. Green, MD, MPH; Ann Hiniker, RN, MS, CNS; Jane Ann Linderbaum, NP[⁎][1]; Frederick A. Masoudi, MD, MSPH,

Echocardiographic identification of cardiovascular sources of emboli to guide clinical management of stroke: A cost-effectiveness analysis

Stroke occurs in more than 500 000 persons annually and is the leading cause of long-term illness and the third leading cause of death in the United States [1]. The debilitating nature of a new-onset stroke is compounded by a high risk for subsequent neurologic and cardiac events [2-4]. The annual cost of stroke in the United States, including the indirect costs of lost productivity, has been estimated to be

Role of Permanent Pacing to Prevent Atrial Fibrillation Science Advisory From the American Heart Association Council on Clinical Cardiology (Subcommittee on Electrocardiography and Arrhythmias) and the Quality of Care and Outcomes Research Interdisciplinary Working Group, in Collaboration With the Heart Rhythm Society

15 billion to

Relation Between Hospital Specialization With Primary Percutaneous Coronary Intervention and Clinical Outcomes in ST-Segment Elevation Myocardial Infarction National Registry of Myocardial Infarction-4 Analysis

30 billion [5]. Cardiovascular sources of emboli may account for 15% to 45% of all strokes [6]. Transesophageal echocardiography has allowed placement of a higher-frequency ultrasonic transducer closer to cardiac structures, thereby producing images with better resolution than those produced by transthoracic echocardiography. Transesophageal echocardiography has substantially improved the identification of thrombi in the left atrium and left atrial appendage. When surgical inspection is used as the gold standard, the sensitivity and specificity of transesophageal echocardiography have been shown to exceed 99% [7]. Transesophageal echocardiography has also improved detection of patent foramen ovale, atrial septal defects, atrial septal aneurysms, spontaneous echocardiographic contrast in the left atrium [8-14], and protruding atheromata in the ascending aorta and aortic arch [15, 16]. Recent studies [16, 17] showed that patients with cardiovascular sources of emboli have a worse prognosis than do patients without cardiovascular sources of emboli. Identification of potential sources of emboli is an important step in reducing recurrent strokes and future expenditures. Anticoagulation has repeatedly been shown to be beneficial in subgroups of patients at risk for stroke [18]. The extent of the benefit of anticoagulation in patients who have had stroke and who have documented or possible thrombi on transesophageal echocardiography is currently unknown and must be weighed against the increased risk for intracranial hemorrhage in such patients. The indications for cardiovascular imaging in patients who have had stroke are inconsistent [19]. Performance of cardiovascular imaging varies among physicians: Some physicians routinely order echocardiography, some use echocardiography in accordance with the patients clinical history, and some rarely order cardiac imaging studies in patients who have had stroke. Concern about the cost of echocardiography may influence practice patterns. To evaluate the benefits, risks, and costs of different diagnostic approaches, we performed a cost-effectiveness analysis of common cardiovascular imaging strategies used in patients who have had stroke. Methods Design A Markov decision analysis [20] was done by using a commercially available computer program (Decision-Maker 7.0, Pratt Medical Group, Boston, Massachusetts) to evaluate nine diagnostic strategies in a hypothetical cohort of 65-year-old patients in normal sinus rhythm with new-onset stroke (Figure 1). (See the Glossary for definitions of terms.) The treat-none and treat-all strategies did not include imaging. In the all-transthoracic, all-transesophageal, and all-sequential strategies, imaging was done in all patients. In the selective-transthoracic, selective-esophageal, and selective-sequential-1 strategies, imaging was done only in patients who had a history of cardiac problems (left ventricular dysfunction or valvular disease). The selective-sequential-2 strategy used a sequential approach in patients with a history of cardiac problems and used transesophageal echocardiography in patients with no such history. Figure 1. Nine possible diagnostic strategies for patients with stroke. The cohort consisted of patients with four types of underlying pathologic condition: thrombi in the left atrium, other potential cardiac sources of emboli, aortic plaque only, and no identifiable cardiovascular source of emboli (Figure 2). Identification of the underlying condition depended on the imaging strategy used (Figure 1). For example, the all-transesophageal strategy identified all potential sources of emboli, the all-transthoracic strategy identified only some of the sources, and the treat-none strategy identified none of the sources. Anticoagulation was started on the basis of the results of the imaging studies. For the imaging strategies included in the base-case analysis, only patients with thrombus received anticoagulants; other patients received aspirin. Figure 2. Health states for the Markov model. The cohort was then followed through monthly cycles for events, including recurrent cerebrovascular accident, intracranial hemorrhage, gastrointestinal bleeding, and death (Figure 2). Event and mortality rates were calculated on the basis of the underlying condition and treatment. Costs and outcomes for each health state were summed over the cycles. Patients in the cohort were followed over a lifetime horizon to provide the most relevant analysis from a societal perspective. Major Clinical Assumptions Several assumptions were necessary to implement the Markov model. First, patients had no obvious clinical cause of stroke (that is, no evidence of periprocedural stroke, recent myocardial infarction, prosthetic valve, known endocarditis, and so on). Second, patients were not receiving anticoagulants or antiplatelet agents at the time of stroke. Third, the subtype of ischemic stroke (such as lacunar or cortical) was independent of the underlying condition. Fourth, transesophageal echocardiography did not cause enough discomfort to decrease quality of life. Fifth, given the same underlying condition, the risk for recurrent stroke was independent of the history of cardiac disease (angina, valvular disease, and so on). Sixth, only the first major complication after stroke was considered in the analysis (for example, patients could not have both recurrent stroke and intracranial hemorrhage). Finally, new-onset and recurrent strokes were assumed to have similar relative effects on quality of life and on risk for death. Results of Diagnostic Imaging and Occurrence of Subsequent Events We performed a systematic review of the literature to gather the best available evidence about the prevalence of various cardiovascular sources of emboli in patients who have had stroke. A MEDLINE search from 1990 to 1995 was done by using cerebrovascular accident and transesophageal echocardiography as keywords (before 1990, transesophageal echocardiography was not a keyword). References from papers identified in the MEDLINE search were used to find relevant studies published before 1990. Studies were chosen if they reported the prevalence of potential cardiovascular sources of emboli identified by transesophageal echocardiography in a defined cohort of patients who had had stroke [8-1417, 21, 22] (Table 1 and Table 4). Studies were distinguished with respect to four characteristics: patient selection (all patients who had had stroke rather than only patients referred for echocardiography), performance of intracardiac contrast studies, blinding of image readers to clinical history, and use of multiple readers. Only single-plane and biplane probes were used in the studies. Thrombi in the left atrium or left atrial appendage were more often identified in studies with selected patients, but other cardiac sources of emboli were identified at similar rates in selected and nonselected patients. Major findings on transesophageal echocardiography did not significantly differ among the studies with regard to use of echocardiographic contrast, blinded readers, or multiple readers. In the papers in which it was mentioned, positive cardiac history was generally defined as atrial fibrillation (patients with atrial fibrillation were excluded from our cohort), decreased left ventricular function, or valvular disease known at the time of transthoracic or transesophageal echocardiography. Rates of identification of aortic plaques varied widely, in part because of poor standardization of diagnostic criteria. Because no group of studies was clearly superior in design and conduct, base-case imaging results were obtained from the mean of the results weighted by the number of participants in each study. Table 1. Systematic Review of the Literature on Transesophageal Echocardiography after Stroke, 1989-1995 Table 4. Table 1. Continued Secondary event rates and mortality rates (including the rate of death from nonvascular causes) were determined by using the best available estimates in the literature (Table 2) [1-418, 23-30]. The estimated relative risk reduction for recurrent stroke (that is, efficacy) with anticoagulation ranged from 0% [23] to 84% [24]. Meta-analyses of studies of patients with atrial fibrillation estimated the efficacy of anticoagulation to be 60% to 67% and the efficacy of aspirin to be 33% compared with that of no therapy [18, 25]. Ezekowitz and colleagues [26] estimated a relative risk reduction of 40% for anticoagulation in patients with a history of atrial fibrillation and stroke, a patient population that may be similar to our patients who had stroke and documented thrombus in the left atrium or left atrial appendage. We chose a relative risk reduction of 33% for anticoagulation compared with aspirin and used a wide range (17% to 67%) for sensitivity analysis. Table 2. Input Variables Prospective information on the incidence of intracranial hemorrhage with anticoagulation after a stroke is also scarce. In a previous decision analysis, Eckman and colleagues [27] estimated the annual incidence of major bleeding to be 4.5% with anticoagulation. In a case series, Landefeld and Goldman [28] found that one third of all major bleeding episodes with anticoagulation were intracranial hemorrhage. Thus, we used a 1.5% annual incidence of anticoagulant-related hemorrhagic stroke. This estimate closely reflects that found in prospective studies of patients with atrial fibrillation that showed an overall incidence of about 1% per year, with higher incidence

ACC/AHA/Physician Consortium 2008 Clinical Performance Measures for Adults With Nonvalvular Atrial Fibrillation or Atrial Flutter A Report of the American College of Cardiology/American Heart Association Task Force on Performance Measures and the Physician Consortium for Performance Improvement (Writing Committee to Develop Clinical Performance Measures for Atrial Fibrillation)

This advisory summarizes the current database on pacing modalities and algorithms used to prevent and terminate atrial fibrillation (AF). On the basis of the evidence indicating that ventricular pacing is associated with a higher incidence of AF in patients with sinus node dysfunction, a patient who has a history of AF and needs a pacemaker for bradycardia should receive a physiological pacemaker (dual chamber or atrial) rather than a single-chamber ventricular pacemaker. For patients who need a dual-chamber pacemaker, efforts should be made to program the device to minimize the amount of ventricular pacing when atrioventricular conduction is intact. Many pacemakers and implantable defibrillators have features designed to prevent AF and to terminate AF with rapid atrial pacing. The evidence to support their use is limited, although these algorithms appear to be safe and usually add little additional cost. For patients who have a bradycardia indication for pacing and also have AF, no consistent data from large randomized trials support the use of alternative single-site atrial pacing, multisite right atrial pacing, biatrial pacing, overdrive pacing, or antitachycardia atrial pacing. Even fewer data support the use of atrial pacing in the management of AF in patients without symptomatic bradycardia. At present, permanent pacing to prevent AF is not indicated; however, additional studies are ongoing, which will help to clarify the role of permanent pacing for AF.

International comparisons of the management of patients with non-ST segment elevation acute myocardial infarction in the United Kingdom, Sweden, and the United States: The MINAP/NICOR, SWEDEHEART/RIKS-HIA, and ACTION Registry-GWTG/NCDR registries

Background— Hospitals with primary percutaneous coronary intervention (PPCI) capability may choose to predominately offer PPCI to their patients with ST-segment elevation myocardial infarction (STEMI), or they may selectively offer PPCI or fibrinolytic therapy based on patient and hospital-level factors. Whether a greater level of hospital specialization with PPCI is associated with better quality of care is unknown. Methods and Results— We analyzed data from the National Registry of Myocardial Infarction-4 to compare in-hospital mortality and times to treatment in STEMI across different levels of hospital specialization with PPCI. We divided 463 hospitals into quartiles of PPCI specialization based on the relative proportion of reperfusion-treated patients who underwent PPCI (≤34.0%, >34.0 to 62.5%, >62.5 to 88.5%, >88.5%). Hierarchical multivariable regression assessed whether PPCI specialization was associated with better outcomes, after adjusting for patient and hospital characteristics, including PPCI volume. We found that greater PPCI specialization was associated with a lower relative risk of in-hospital mortality in patients treated with PPCI (adjusted relative risk comparing the highest and lowest quartiles, 0.64; P=0.006) but not in those treated with fibrinolytic therapy. Compared with patients at hospitals in the lowest quartile of PPCI specialization, adjusted door-to-balloon times in the highest quartile were significantly shorter (99.6 versus 118.3 minutes; P<0.001), and the likelihood of door-to-balloon times exceeding 90 minutes was significantly lower (relative risk, 0.78; P<0.001). Adjusting for PPCI specialization diminished the association between PPCI volume and clinical outcomes. Conclusions— Greater specialization with PPCI is associated with lower in-hospital mortality and shorter door-to-balloon times in STEMI patients treated with PPCI.

Standardized Outcome Measurement for Patients With Coronary Artery Disease: Consensus From the International Consortium for Health Outcomes Measurement (ICHOM)

Consistent with the national focus on healthcare quality, the American College of Cardiology (ACC) and the American Heart Association (AHA) have developed a multifaceted strategy to facilitate the process of improving clinical care. The first aspect of this effort is the creation of clinical practice guidelines that carefully synthesize available evidence to guide better patient care. Such guidelines are written to suggest diagnostic or therapeutic interventions that apply to patients in most circumstances, but clinical judgment is required to adapt these guidelines to the care of individual patients. The guidelines are based on available evidence, providing varying degrees of recommendation (Table 1). Occasionally, the evidence supporting a particular aspect or process of care is so strong that failure to perform such actions reduces the likelihood of optimum patient outcomes. Table 1. Applying classification of …