Patients slated for cardioversion for atrial fibrillation and who are on a DOAC may not need to undergo the routine practice of transesophageal echocardiography (TOE) before the procedure, say Australian researchers.
Skipping the invasive diagnostic assessment could save hospitals thousands of dollars each year while reducing patient exposure to the small but well recognised risks associated with TOE.
TOE is often performed before cardioversion if a patient hasn’t logged four weeks of INRs in the therapeutic range or isn’t in sinus rhythm on procedure day, electrophysiologist Associate Professor Gerald Kaye told the limbic.
“But that’s in patients on warfarin,” he stressed.
“There’s concern about the newer agents because we don’t routinely measure blood plasma levels like we do for warfarin so you can’t easily tell how anticoagulated someone on a DOAC really is.”
The dilemma is that if a patient has forgotten to take their blood thinner for a day or two – or even a single dose – they may be exposed to an increased risk of stroke during cardioversion, Professor Kaye said.
A practice that many hospitals have adopted to mitigate that risk is to recommend all patients on the newer agents undergo a TOE prior to cardioversion to screen for atrial thrombus.
“That’s a very big undertaking for most units so we decided that we would look at this in a different way.”
Cardiologists from the Princess Alexandra Hospital in Brisbane have been trialling the safety of a verbal questionnaire to assess patient compliance to their anticoagulant instead of relying on TOE.
Professor Kaye who is the lead investigator on the trial, published in Heart Lung and Circulation this month, said the simple four-question intervention has been shown to be safe and can be delivered by specialist nurses.
“At some stage you either rely on the patient completely or you have to do something else … if you’re not going to rely on the patient telling you what they are doing then there would have to be another test and the TOE would be the best one.”
The trouble is that test is not without risk and it carries significant cost with the current Medicare Benefits Schedule rebate for each test set at $275.
And the growing number of patients on a DOAC scheduled for cardioversion means routine TOE is not an ideal strategy for many hospitals.
“There’s a big shift away from warfarin, we’ve seen a marked increase in DOACs – over the last three years in our hospital its gone up from 30% to a peak of 75% so nearly three quarters of patients have come up on a DOAC.”
The questionnaire takes around five to 10 minutes to complete. Professor Kaye and colleagues have now reported on the audit of 335 cardioversion cases that used the intervention as an initial screen for anticoagulation compliance.
Of the whole group 26 patients in the warfarin group underwent TOE based on their INR reading and 25 patients in the DOAC group were picked up as non-compliant based on the questionnaire who then went on to TOE prior to cardioversion.
No stroke or systemic embolism was detected in the 30 days following cardioversion with 100% patient follow-up.
The questions very specifically address compliance:
Do you ever forget to take your medication, even for a day?
How often in an average week would you forget or miss a dose of your medication?
Are you aware that missing a dose of your blood thinner before the scheduled cardioversion could lead to a serious complication such as stroke
When was the last time you forgot or missed a dose of your blood thinner?
“If there is any doubt about the reliability of the patient’s answers then we would proceed with the TOE. The study shows the intervention is safe and out of 335 patients we only ended up doing a TOE in 51 patients – that’s a big cost and time saving and we’re not exposing those patients to any increased risk,” Professor Kaye added.
While the questionnaire prior to cardioversion is already in place at Princess Alexandria Hospital Professor Kaye thinks it may be a while before the protocol becomes recommended over routine TOE in guidelines.
This is an observational study and we weren’t statically powered to show an effect on stroke – a study that had stroke as an endpoint would need a huge number of patients because stroke is still very infrequent with cardioversion – I’d be surprised if anyone would do a study like that.
That’s why we published our findings – because we thought it would be important to get some kind of feel clinically on whether this was the right thing to do or not.”