The New Guideline for AFib: A Call for Patient-Centered Decision Making

We are at a unique point in history regarding the management of atrial fibrillation (AF). The incidence and prevalence of AF continue to rise to epidemic proportions,¹ with current estimates easily surpassing projections from a decade ago.² Among Medicare beneficiaries, the onset of AF leads to a change in the trajectory of hospitalization, care utilization, and survival,^3,4 costing Medicare $16 billion each year to treat new AF and adding $14,000 per patient per year in incremental costs.^5-7

Fortunately, treatment options for AF have flourished over this same decade. Catheter ablation, once considered a fringe therapy performed at only a handful of academic centers, has matured into a mainstream therapy with compelling evidence to support its efficacy and effectiveness.^8,9 Antiarrhythmic drug therapy is more widely used, and the boundaries of appropriateness and safety of rhythm control strategies are more clearly defined. Most importantly, our ability to prevent AF-related stroke has been significantly improved with enhanced risk prediction tools,¹⁰ new drug therapies that in many situations trump warfarin,¹¹ and a greater understanding of the strengths, limitations, and quality of care considerations for warfarin.

Yet, with all of these choices, along with a constant flux of new evidence, it daunting for even the most erudite or experienced clinician to know treatment options are best across the many permutations of symptom burden, stroke risk, and comorbidities. Moreover, until now, AHA’s AF guidelines have been fragmented across a patchwork of guideline updates and advisories,^11,12 while many recommendations have remain unchanged for the past 8 years.¹³

This new guideline, developed jointly by the AHA, the American College of Cardiology, and the Heart Rhythm Society, and in collaboration with the Society of Thoracic Surgeons, represents the most comprehensive evidence synthesis and guidance to date on AF, superseding the 2006 document.¹⁴ The writing group did not just survey the state of science from published studies, but also evaluated 22 other related guidelines or statements (Table 2), many from other professional societies. Several important updates deserve mention:

Classification of AF

The classification scheme has been revised and simplified to describe AF as paroxysmal, persistent, and longstanding persistent (Table 4), which has greater consistency with studies of rhythm control. A list of risk factors for AF has been greatly expanded to include clinical, structural, and biomarker characteristics (Table 5). Associated atrial arrhythmias, such as atrial flutters and atrial tachycardias, are also described in mechanistic and clinical detail (Figure 1).

Risk stratification and treatment threshold for stroke

The CHA₂DS₂-VASc score has been recommended as the only score to apply when assessing stroke risk in nonvalvular AF. The CHADS2 score is no longer recommended. CHADS₂ is still preferred by the American College of Chest Physicians (ACCP),¹⁵ while the European Society of Cardiology (ESC) guideline update recommends the use of either score.¹⁶

The new guidelines recommend oral anticoagulation in patients with a CHA₂DS₂-VASc ≥ 2, no treatment (not even aspirin) with a score of 0, and optional aspirin with a score of 1 (Table 6). This represents the biggest change to the guidelines. However, the recommendation differs from other professional guidelines such as the ESC guideline, which favors anticoagulation in CHA₂DS₂-VASc of 1, unless the single risk factor is considered a low-risk feature. The ACCP recommends no treatment with a CHADS₂ = 0, although such patients may frequently meet anticoagulation criteria based on the CHA₂DS₂-VASc score under the current guidelines.

Importantly, the new guideline advocates against the used of bleeding risk scoring systems, but provides additional guidance in certain high-risk populations such as patients with end-stage renal disease.

Anticoagulant selection for stroke prevention therapy

The new guideline does not endorse any single anticoagulant as the preferred therapy. Rather, it advocates patient centered decision-making as the top-line Class I recommendation (Table 6):

“In patients with AF, antithrombotic therapy should be individualized based on shared decision-making after discussion of the absolute and RRs of stroke and bleeding, and the patient’s values and preferences.”

The emphasis on patient-centeredness represents a critically important and appropriate shift in recommendations, emphasizing the doctor-patient relationship and preference-based therapy. However, the guideline expands upon recommendations, contraindications, and dosing of all anticoagulants in moderate to severe chronic kidney disease,¹¹ which is an important risk factor for bleeding, particularly with several of the new target specific oral anticoagulants (Table 8).

The guideline does recommend consideration of the newer agents in patients with poor control on warfarin but unfortunately does not define poor control, such as what values of INR time in therapeutic range would be considered acceptable.

Catheter ablation

The new guideline provides support for catheter ablation for paroxysmal AF in drug refractory cases (Class I) and as first-line therapy (Class IIa), based on randomized clinical trial data. Recommendations for ablation in persistent AF and in heart failure are also outlined.

Other important changes include further guidance on optimal control of the ventricular rate (Table 9), anticoagulation at time and after cardioversion (Table 11), perioperative management for cardiac and thoracic surgery, and inpatient versus outpatient initiation of antiarrhythmic drug therapy.

The Road Ahead

Despite numerous advances in AF treatment, there remain significant knowledge gaps that remain unanswered. For example, how much AF is required to cause stroke? What is the temporal relationship of AF onset and stroke? Over a patient’s lifetime, does catheter ablation delay or curtail the natural history of AF? Should patients be screened for silent AF as they are for hypertension? These questions are difficult but essential to answer.

Finally, these recommendations, although exhaustive, add substantial complexity to the care of AF. What will be the best solutions to improve use of evidence-based therapies and minimize variation of care across providers, hospitals, and specialties?¹⁷ How will we ensure that decisions are patient-centered? The AHA has launched a new Get With the Guidelines initiative in AF (GWTG-AF) that will provide participating hospitals a framework for quality improvement of inpatient and post-discharge AF care. However, there are few, if any, policy measures or incentives in place to improve outpatient AF care.

Nonetheless, the writing group is to be congratulated for producing this exhaustive guideline. Achieving consensus on so many issues in AF is no easy task, particularly in cases with poor evidence. It is now up to all of use to apply these guidelines in an effective, patient-centered way that can decrease the public health burden of AF.