ESC Congress FA eBook 2016 - 15

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ablation (RFCA). The rates of recurrent AF were comparable to that seen in younger patients; however, elderly
patients had longer hospital stays and there were more
procedure related complications, particularly after AF
ablations that lasted > 100 minutes.
Although there are no existing recommendations for
treatment of elderly patients with AF, prior studies have
found that ablation is safe and effective in the elderly
[Nademanee K et al. Heart Rhythm. 2015]. In this study,
the authors performed a propensity-matched analysis to
describe the outcomes, safety, and length of hospital stay
in patients (n = 1825) who underwent RFCA for symptomatic drug-refractory AF. For the analysis, patients
were stratified into 3 groups according to age (group 1,
age < 55, n = 675; group 2, ≥ 55 to < 75, n = 1041; group
3, ≥ 75, n = 109) and matched on AF type and gender by
a 1:3 propensity matched analysis. In the oldest group
the study population was mean age 77.3 years and 35.8%
women; 26.6% had paroxysmal AF.
Open irrigated-tip catheter and 3D electro-anatomical
mapping were used when performing the ablation. The
endpoints of the study were AF recurrence from index
RFCA, procedure-related complications, and duration
of hospital stay. These endpoints were compared among
the groups with and without propensity score matching
for gender and AF type.
Heart failure, hypertension, diabetes, stroke/transient
ischemic attack, were more common, CHADS2 scores were
higher, and there was more frequent use of angiotensin
receptor blockers and statins in the elderly population even
after propensity score matching. Left atrium dimension
and volume index were greater and left ventricular ejection
fraction was lower in patients aged ≥ 75 years.
The rate of complications from RFCA was higher among
elderly patients with persistent AF both overall and within
the matched population (all P < .05). However, the rates of
complications were similar across the age groups among
those with paroxysmal AF. There was no difference in procedural complications in patients < 75 years old regardless
of how long the ablation lasted. In contrast, the rate of procedure-related major complications was significantly higher
among patients aged ≥ 75 years when the ablation time was
≥ 100 min (P = .002 overall; P = .001 within the matched case
group). Elderly patients also had a significantly longer hospital stay compared with patients aged < 75 years (P < .001).
Despite higher rates of coexistent cardiovascular risk
factors, the success rate and safety of RFCA in AF elderly
patients did not differ significantly from younger patients.
AF recurrence in the propensity score-matched population was not significantly different among the age groups.

ESC CONGRESS 2016
IN REVIEW

FOCUS ON ARRHYTHMIAS

Over- and Under-dosing of
NOACs Increases Risk of
Adverse Events: ORBIT-AF II
Written by Maria Vinall

Jonathan Piccini, MD, MHS, Duke University Medical
Center, Durham, North Carolina, USA, reported results
from ORBIT-AF II (Outcomes Registry for Better Informed
Treatment of Atrial Fibrillation, Phase II) revealing that
the under- or over-dosing with non-vitamin K antagonist
oral anticoagulants (NOACs) may increase the risk of
bleeding, cardiovascular events, hospitalization, and allcause mortality in some patients with newly-diagnosed
atrial fibrillation (AF) who are naïve to anticoagulants.
This was a prospective study using data for 5738
patients from the ORBIT AF II registry to examine NOAC
dose-selection and outcomes in community practice.
The prescribed NOAC dose for newly-diagnosed (within
6 months) AF patients and/or those transiting to NOACs
within 3 months was compared with the dose listed in
the US Package Insert for each drug and patients were
classified as receiving appropriate (on-label) or under/
over-dosed (off-label) NOAC therapy. Drugs used in < 100
patients (eg, edoxaban) were excluded. The study compared baseline characteristics and major cardiovascular
and bleeding outcomes from 6 months to 2 years after
the introduction of NOACs. Adverse event outcomes
included stroke or systemic embolism, myocardial
infarction, ISTH -defined major bleeding, cause-specific
hospitalization, and all-cause mortality, compared across
dosing categories. Dr Piccini presented the results after 1
year of follow-up.
Most patients (54%; 3078/5738) received rivaroxaban,
39% (2235/5738) received apixaban, and 7.4% (425/5738)
received dabigatran. Although the NOAC dose was considered to be appropriate for the majority of patients
(87%; 5000/5738), 541 patients (9.4%) were considered to
have been were under-dosed and 197 (3.4%) over-dosed.
The percentages were similar across the 3 agents.
Compared to patients receiving an on-label (appropriate) NOAC dose, those receiving an off-label (underor over-) dose were older, more likely to be female, and
had lower creatinine clearance. Higher risk patients were
also more likely to receive an off-label dose. Notably,
53% of patients with a low ORBIT bleeding score were
under-dosed (Table 1).
Adverse events were more common in patients dosed
inappropriately. After adjustment for clinically important
co-variates and site variance, there were no statistically
significant differences in bleeding risk. For cardiovascular outcomes, after adjustment, under-dosing was

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