Atrial fibrillation: Effective strategies using the latest tools

Tools to help assess patients’ bleeding risk

Of the available scoring mechanisms to identify risk factors for bleeding, 3 have been specifically validated in AF populations (ie, ATRIA,³³ HEMORR₂HAGES,³⁴ and HAS-BLED³⁵). Of the 3, HAS-BLED is superior,³⁶ the most practical, and recommended by expert guidelines.^18,21,22 Additionally, HAS-BLED has good correlation with intracranial hemorrhage risk. The HAS-BLED score ranges from 0 to 9 points with one point assigned for each of the following:³⁵

• Hypertension–uncontrolled with systolic BP >160 mm Hg
• Abnormal liver function–cirrhosis, bilirubin >2× normal, or liver enzymes >3× normal
• Abnormal renal function–dialysis, transplant, or serum creatinine >2.26 mg/dL
• Stroke history–including lacunar infarcts
• Bleeding predisposition–history of major bleeding due to any cause
• Labile international normalized ratio (INR)–time in therapeutic range <60%
• Elderly–age >65 years
• Drug–antiplatelet agents, including nonsteroidal anti-inflammatory drugs
• Alcohol usage–>8 drinks per week.

Patients with a HAS-BLED score ≥3 warrant additional monitoring and attempts to reduce bleeding risk by addressing modifiable risk factors. Bleeding risk scores should not be used to exclude patients from anticoagulation therapy.⁵ In fact, the British National Institute for Health and Clinical Excellence (NICE) guidelines state that anticoagulation should not be withheld solely due to fall risk.²¹

Also, anticoagulation with warfarin should not be permanently discontinued because of a single GI bleed, since restarting warfarin is associated with decreased risks of thromboembolism and mortality and a statistically insignificant increase in recurrent GI bleeding.³⁷ Restarting DOAC therapy following a GI bleed has not been evaluated in clinical trials; however, it may be reasonable to use one of the DOAC doses with a lower risk of GI bleeding (dabigatran 110 mg BID, apixaban 5 mg BID, or edoxaban 30 mg/d) in patients who have experienced a GI bleed on warfarin or another DOAC.^18,22

An online calculator is available that uses CHA₂DS₂-VASc and HAS-BLED scores to determine an individual’s risk/benefit profile with the various anticoagulation strategies available (https://www.sparctool.com). Consider percutaneous left atrial appendage occlusion if the risks of anticoagulation truly exceed the benefits.³⁸

Rate control vs rhythm control

Most patients who present with AF require immediate ventricular rate control to reduce symptoms. In the acute setting, this can be accomplished with intravenous (IV) beta-blockers or IV calcium channel antagonists.^5,39 If the patient is hemodynamically unstable, urgent direct-current cardioversion is the preferred treatment strategy and should not be delayed pending anticoagulation. IV amiodarone can be used in the ICU patient who does not require cardioversion, but is unable to tolerate beta-blockers or calcium channel antagonists.⁴⁰ Once the patient is stable, long-term treatment focuses on ventricular rate control or restoration and maintenance of sinus rhythm.

Direct oral anticoagulants are not suitable for patients who frequently miss doses.

The AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial enrolled 4060 patients (mean age 70 years, mean follow-up 3.5 years) with paroxysmal and persistent AF and randomized them to either pharmacologic rate control or rhythm control.⁴¹ No significant differences were found in all-cause mortality or in the composite secondary endpoint of death, ischemic stroke, anoxic encephalopathy, major bleeding, or cardiac arrest. In addition, no significant differences emerged in quality of life or global functional status. The number of patients requiring hospitalization during follow-up was significantly lower in the rate-control group vs the rhythm-control group (73% vs 80%; P<.001). Anticoagulation was encouraged but not mandated in the rhythm-control group after 4 weeks in sinus rhythm, and there was a trend toward higher mortality in the rhythm-control group (27% vs 26%; P=.08).

Patients <65 years were excluded from the AFFIRM trial. When younger patients experience significant symptoms, early referral to Cardiology should be considered to discuss the long-term benefits and risks of a rhythm-control strategy. Regardless of age, when patients remain symptomatic despite rate- or rhythm-control management, the strategy should be changed.⁵

Rate-control targets and options

Target heart rates should be individualized. The 2014 ACC/AHA/HRS guideline recommends a resting target heart rate <80 beats per minute (bpm) in symptomatic patients.⁵ In patients with permanent AF who remain asymptomatic at higher resting heart rates, a more lenient rate-control strategy (resting heart rate <110 bpm) has demonstrated outcomes equivalent to those of a more strict approach (resting heart rate <80 bpm and heart rate during moderate exercise <110 bpm).⁴² Pharmacologic rate-control options include beta-blockers, non-dihydropyridine calcium channel antagonists, and digoxin (TABLE 3⁵). Digoxin is associated with increased all-cause mortality in patients with AF regardless of HF status (HR=1.4; 95% CI, 1.2-1.6, P=.0001).⁴³ Digoxin should be reserved for patients who are sedentary or have inadequate control with first-line medications.⁵