9 August 2018

Australia splits from US over AF screening

Cardio Patients

The vice-president of the RACGP has defended a proposal to screen older adults for atrial fibrillation (AF), even though this directly conflicts with new US recommendations.

Associate Professor Charlotte Hespe, who co-authored Australia’s first AF guidelines, said screening asymptomatic adults aged 65 or more could prevent strokes and was unlikely to cause any of the harms identified by US experts.

By contrast, the US Preventative Services Task Force recently said there was insufficient evidence to support ECG screening in asymptomatic patients at high risk of CVD.

The US reasoning was that ECG screening would not change the management of risk factors, and could lead to serious harms from invasive confirmatory testing and treatment, including angiography and revascularisation.

However, Professor Hespe said, under the Australian guidelines, most patients diagnosed with AF who did not have symptoms or signs of ischaemia would not undergo these invasive procedures.

Contrary to the US task force’s statement, AF diagnosis in Australia triggered a treatment trajectory that was completely different to management of CVD risk, she said.

Patients at high risk of CVD would generally be considered for statins, blood pressure-lowering medications and antiplatelets, such as aspirin.

While cardioversion remained first-line treatment for acute rhythm control when clinically indicated, most patients with AF would be medically treated.

Based on their CHA?DS?-VASc score, patients with AF would be prescribed anticoagulants plus or minus a rate control medication such as beta blockers, to lower their risk of future stroke, she said.

Not all patients with AF would be otherwise considered at high risk of CVD, so screening for AF in all people 65 and older, was likely to identify some patients who otherwise might miss out on treatment, she said.

Professor Hespe’s own GP clinic in Glebe in Sydney has been screening older patients for AF for the past five years as part of an annual program tied to influenza vaccinations.

The patients hold a screening device for 60 seconds during the consultation, which produces a single-line ECG. If the result comes back as positive or uncertain, the clinic does an ECG to confirm the diagnosis.

The immediacy of the diagnosis with opportunistic point-of-care screening in a general practice setting is preferable to diagnosis in other settings as it reduces anticipatory anxiety and time lag between diagnosis and treatment, according to the Australian guidelines published in the MJA this month.

Every year, around one to three people are diagnosed with AF based on her clinic’s screening program, Professor Hespe said. More broadly, AF screening would pick up AF in about 1.4% of patients aged 65 and older.

“So, it’s not big numbers, but it’s not a big-time burden either because they are in the surgery already having their flu vaccination,” Professor Hespe said.

Not a single patient diagnosed with AF through her clinic’s screening program had gone on to have an invasive procedure, she said.

“So, that’s where I would question that as being the reason you wouldn’t do it.”

JAMA, 12 June

MJA, 2 August