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Journal Club

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kim matthews

on 28 October 2014

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Transcript of Journal Club

Journal Club
Kim Matthews

Methods
55 years or older

Dx of cryptogenic cva/tia by stroke specialist within previous 180 days.
-embolic CVA on neuroimaging
-TIA (focal unilateral motor or language deficit; hemianopia,
lasting <24 hours

At least one 12-lead ECG (without a fib) obtained as part of the routine clinical work-up

No previous hx, dx, or documentation of atrial fibrilation

Post CVA/TIA workup including a 24hr Holter monitor without atrial fibrillation or atrial flutter ≥30 sec in duration

Patient must be at risk - in the investigator's clinical judgment, would consider ordering a repeat Holter
monitor as part of clinical care.

Previously obtained:
-brain imaging with CT or MRI,
-vascular imaging of the extracranial and intracranial circulation with either CT or MR angiography to exclude significant large vessel occlusive disease
-TTE/TEE to exclude thrombus/structural heart disease


patient selection
Author's Conclusions
- feasible - >75% completed 3+ weeks monitoring

-superior to standard 24 hour ECG monitoring and clinical detection

-doubled anticoagulation use for secondary stroke prevention - clinically meaningful

-finding even brief atrial fibrillation in this population is clinically important - likely underestimated the burden of a fib


Atrial Fibrillation in Patients with Cryptogenic Stroke



Study Background
Atrial fibrillation is a significant preventable cause of ischemic stroke -the cause of 1 in 6 strokes

Anticoagulation therapy reduces stroke risk by 64%

Antiplatelet therapy reduces risk by 22%
intermittent atrial fibrillation

may be silent/asymptomatic
easily undetected
often suspected as underlying cause of "cryptogenic stroke"
1 in 4 strokes and 50% of TIAs have no diagnosed cause after routine workup = Cryptogenic Stroke

Anticoagulation therapy is not recommended if a fib has not been documented

Current Standard of Care
tele monitoring for 24-72 hours during hospitalization

and/or 24-48 hour holter monitoring as outpatient
Hypothesis
Extended cardiac monitoring would increase detection of atrial fibrillation
Increase rates of appropriate therapy

Decrease risk of recurrent stoke
open label

multicenter

two-arm

unblinded

randomized controlled trial
2/1/2009 until 2/1/2013
30 day event recording (intervention)
or
24 hour Holter Monitoring (control)

Meta-analysis of studies utilizing TOAST classification:
-22.0-29.1% of strokes are cardioembolic
-35.438.1% are of undetermined etiology.


21 centers in Canada

Previously documented atrial fib/flutter
-PMHx of
-ECG, Holter, or telemetry evidence of

Exclusively retinal stroke or TIA event

CVA/TIA with diagnosed etiology (i.e)
-probable small-vessel (lacunar) disease
-probable large-vessel disease
-cervicocephalic artery dissection
-venous sinus thrombosis
-hypercoagulable state

Planned carotid endarterectomy within 90 days

Participating in another clinical trial

Echocardiography finding with evidence-based
indication for long-term anticoagulation
-mechanical heart valve or thrombus

Endocarditis

Pacemaker or ICD

Known skin reactions to synthetic polymers or silver
Exclusion Criteria
DJ Gladstone

NEJM June 16, 2014
572 Enrolled and Randomized
















287 Were assigned to 30 day ECG monitoring
284 Received assigned intervention
3 Did not receive assigned
intervention
1 Had new diagnosis of cancer
2 Withdrew from study
1 Was excluded from all analyses
owing to withdrawal from study
immediately after randomization
with no baseline data recorded
280 Were included in 90-day follow-up
7 Were lost to follow-up
1 Died from new ischemic stroke
1 Had adverse skin reaction
5 Withdrew from study
285 Were assigned to 24-hour ECG monitoring
277 Received assigned intervention
8 Did not receive assigned intervention
1 Died from new ischemic stroke
2 Had medical illness
1 Had pacemaker inserted
1 Moved out of country
3 Withdrew from study

279 Were included in 90-day follow-up
6 Were lost to follow-up
1 Died from new ischemic stroke
5 Withdrew from study
285 Were included in all analyses
286 Were included in all analyses
280 Were included in primary
analysis
6 Were excluded because the
primary outcome could not be
assessed

284 Were included in secondary
analysis
2 Were excluded because they did
not undergo any monitoring
277 Were included in primary
analysis
8 Were excluded because the
primary outcome could not be
assessed

277 Were included in secondary
analysis
8 Were excluded because they did
not undergo any monitoring
Primary Objective:
Determine diagnostic yield of a 30-day cardiac event versus repeat 24-hour Holter monitor in patients with a recent stroke/TIA of undetermined etiology, following routine diagnostic work-up including an initial negative Holter monitor


Secondary Objectives:
Determine if 30-day monitoring could result in a change within clinical management
(more patients treated with anticoagulation)

Assess patient adherence to 30-day monitoring
(%patients wearing device >75% of the target 30-day period)

Assess 1 and 2-year rates of recurrent ischemic stroke/TIA, death, hemorrhagic stroke, major adverse bleeding events, detection of atrial fibrillation/flutter outside of the
study protocol
-instructed to wear device as many hours as possible for 30 days

-all a fib episodes reviewed by a cardiologist and an internist (unaware of patient's demographic or clinical characteristics)

-report of the monitor results sent to the patient’s stroke consultant/treating physician for clinical decision-making.

-patients contacted by phone weekly during the monitoring period to assess compliance and ensure that the maximal number of events has not yet been reached.
Intervention Group
Control Goup
-assigned to one additional 24 hour ECG monitoring session using conventional Holter Monitor from local lab at study site

-reports reviewed centrally by one physician
Compliance of Intervention Group
233 of 284 (82.0%) completed 3 or more weeks


Patients without detected A Fib:

-204/240 (85.0%) completed at least 3 weeks

-148/240 (61.7%) completed 4 weeks
no other control group (pts without cva/tia)

and

lack of known minimal time to define significant atrial fibrillation

and

cannot prove causation if atrial fibrillation is found after a stroke




Further Directions
Follow up on intervention vs. control group
-outcomes

Additional control group without cva/tia

Quicker enrollment after index event
-analysis of %A.Fib. detected in early enrollment vs. later enrollment

Use of newer recording devices
- longer/infinite recording capability
-randomization at mean ~3.5 months from index event

-recording limited period of a fib (2.5 sec)


Number needed to screen =
8
&
NNT in
SECONDARY
prevention =
12


So,
could theoretically prevent
1/96
strokes

Stroke Prevention in Atrial Fibrillation Investigators.
The Stroke Prevention in Atrial Fibrillation study:
final results. Circulation.
1991; 84:527–39.
Randomised trial of warfarin and aspirin for prevention of thromboembolic complications in
chronic atrial fibrillation (AFASAK).
Lancet. 1989;
1:175–8.
The effect of low-dose warfarin on the risk of stroke in nonrheumatic atrial fibrillation.
N Engl J Med.
1990; 323:1505–11.
Canadian Atrial Fibrillation Anticoagulation (CAFA) study. J Am Coll Cardiol.
1991; 18:349–55
Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators. Warfarin in the prevention of stroke associated with nonrheumatic atrial fibrillation.
N Engl J Med. 1992; 327:1406–12
European Atrial Fibrillation Trial Study Group Secondary
prevention in nonrheumatic atrial fibrillation after transient
ischemic attack or minor stroke. Lancet. 1993;
342:1255–62
Critique - Pitfalls
The point is that screening should be done on CVA/TIA patients who are at risk for atrial fibrillation
thus, finding any amount of atrial fibrillation would be significant

AND

at least help in risk stratification
(versus
primary
prevention, NNT = 30)
6 / 277
21 / 284
12 / 263
2 / 251
7 / 249
2.1%
7.3%
4.5%
0.8%
2.8%
Full transcript