Reed Miller

June 14, 2012

June 13, 2012 (Nice, France)— The CHADS2 score, routinely calculated to predict the risk of stroke in coronary bypass surgery patients, also identifies which of those patients are at risk for atrial fibrillation, according to a study presented today here at Cardiostim 2012 [1].

CHADS2 was created to assess an individual patient's risk of stroke by combining congestive heart failure or low left ventricular ejection fraction, hypertension status, age, diabetic status, and previous transient ischemic attack (TIA) or stroke into a single number from zero to 6. "The CHADS2 is already validated and easy to use. This study shows it can also predict the incidence of postop afib. It's the simplest thing because all of these risk factors are also the risk factors for postop complications, as shown in other studies, [including] postop atrial fibrillation," study author Dr Alireza Nazeri (Texas Heart Institute, Houston) told heartwire.

Nazeri and colleagues retrospectively analyzed the 5985 patients who underwent coronary artery bypass at their institution from 2001 through 2010, excluding patients with a history of atrial fibrillation or valve disease. They then identified the frequency of postoperative AF in three CHADS2 score intervals, 0–1 (low), 2–3 (medium), and high. A total of 1611 patients had a postoperative atrial fibrillation event, including 22%, 29%, and 35%, of the low, medium, and high CHADS2 groups, respectively.

Patients in the high-CHADS2-score group were 1.9 times as likely to develop postop AF as patients in the low-CHADS2-score group (p<0.0001). Patients in both the high and medium groups combined were 1.5 times as likely to develop postop AF as those in the low group (p<0.0001). The difference between the medium and low group was not statistically significant.

"Everybody, when they go to the patient's bedside and see the patient going into CABG, already uses the CHADS2 score. Use it, and you'll know if the patient is at high risk for afib. So if I know that, I want to make sure the patient is on beta blockers preop and I want to make sure, if I can, that they start on amiodarone. [That's key], because I know that if I give amiodarone to somebody at low risk for afib, I'm just going to be buying the risks of amiodarone, but if I use it somebody at high risk for afib and I already know that, then I can have a risk/benefit ratio that is more benefit."

Commenting on the study, Dr Jerzy Krzysztof Wranicz (Medical University of Lodz, Poland) commended the study by Nazeri et al and also suggested that correlating CHADS2 with echocardiography parameters would further refine the prediction of which coronary bypass surgery patients could most likely benefit from an antiarrhythmic drug.

Nazeri pointed out that previous research has shown that age and white race are also correlated to higher risk of postop AF risk. Also, his group is developing more detailed scoring system and will test that prospectively in clinical practice. But for this study, "we just wanted to look at the clinician at the bedside who wants to look at the patient using the CHADS2 score and what can they do with it."

The authors reported no potential conflicts of interest.


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