Decisions, Decisions: Stroke Risk Scoring Systems
The risk for stroke varies widely among patients with AF, so primary care clinicians can pick among several scoring systems to estimate the risk for stroke and guide the decision on whether to initiate anticoagulation therapy.
The ACC/AHA guidelines do not state a preference for a particular instrument. The Congestive heart failure, Hypertension, Age, Diabetes mellitus, Stroke, Vascular disease, Sex (CHA2DS2-VASc) score is the most widely used and validated instrument, Joglar said. He usually recommends anticoagulation if the CHA2DS2-VASc score is > 2, dependent on individual patient factors.
“If you have a CHA2DS2-VASc score of 1, and you only had one episode of AF for a few hours a year ago, then your risk of stroke is not as high as somebody who has a score of 1 but has more frequent or persistent AF,” Joglar said.
None of the systems is perfect at predicting risk for stroke, so clinicians should discuss options with patients.
“The real message is, are you talking about the risk of stroke and systemic embolism to your patient, so that the patient understands that risk?” he said.
Patel also said measuring creatine clearance can be analogous to using an instrument like CHA2DS2-VASc.
“I often think about renal disease as a very good risk marker and something that does elevate your risk,” he said.
Which Anticoagulant?
Although the ACC/AHA guidelines still recommend warfarin for patients with AF with mechanical heart valves or moderate to severe rheumatic fever, direct oral anticoagulants (DOACs) are the first-line therapy for all other patients with AF.
In terms of which DOACs to use, the differences are subtle, according to Patel.
“I don’t know that they’re that different from each other,” he said. “All of the new drugs are better than warfarin by far.”
Patel pointed out that dabigatran at 150 mg is the only DOAC shown to reduce the incidence of ischemic stroke. For patients with renal dysfunction, he has a slight preference for a 15-mg dose of rivaroxaban.
Mandrola said he mainly prescribes apixaban and rivaroxaban, the latter of which requires only once a day dosing.
“We stopped using dabigatran because 10% of people get gastrointestinal upset,” he said.
Although studies suggest aspirin is less effective than either warfarin or DOACs for the prevention of stroke, Joglar said he still sees patients who come to him after being prescribed low-dose aspirin from primary care clinicians.
“We made it very clear that it should not be recommended just for mitigating stroke risk in atrial fibrillation,” Joglar said. “You could use it if the patient has another indication, such as a prior heart attack.”
Does My Patient Have to Be in Normal Sinus Rhythm?
The new guidelines present evidence maintaining sinus rhythm should be favored over controlling heart rate for managing AF.
“We’ve focused on rhythm control as a better strategy, especially catheter ablation, which seems to be particularly effective in parallel to lifestyle interventions and management of comorbidities,” Joglar said. Rhythm control is of particular benefit for patients with AF triggered by heart failure. Control of rhythm in these patients has been shown to improve multiple outcomes such as ejection fraction, symptoms, and survival.
Patel said as a patient’s symptoms increase, the more likely a clinician will be able to control sinus rhythm. Some patients do not notice their arrhythmia, but others feel dizzy or have chest pain.
“The less symptomatic the patient is, the more likely they’re going to tolerate it, especially if they’re older, and it’s hard to get them into sinus rhythm,” Patel said.