Transient Atrial Fibrillation and Risk of Stroke after Acute Myocardial Infarction

Transcription

1 Transient Atrial Fibrillation and Risk of Stroke after Acute Myocardial Infarction Doron Aronson MD, Gregory Telman MD, Fadel BahouthMD, Jonathan Lessick MD, DSc and Rema Bishara MD Department of Cardiology RAMBAM Health Care Campus Haifa, Israel

2 DECLARATION OF CONFLICT OF INTEREST -Nothing to declare

3 Introduction Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI), with a reported incidence ranging from 6% to 19% The management of AF patients presenting with an acute coronary syndrome (ACS) poses several dilemmas given the need to balance stroke prevention and recurrent coronary events or stent thrombosis against the risk of bleeding few data are available with regard to patients without previous AF who develop transient new-onset AF during the acute event

4 Introduction Current European and American guidelines for the management of AF in the setting of ACS mainly pertain to patients with previously known AF In patients with known AF who present acutely with an ACS, the so-called triple (oral) therapy consisting of dual oral antiplatelet agents plus OAC, should be considered (Class Ic) However, triple therapy and dual therapy with aspirin and oral anticoagulant are associated with a high frequency of major bleeding events

5 Introduction In patients with transient AF the arrhythmia is frequently attributed to acute hemodynamic changes, elevation of filling pressures and heart failure, inflammation or ischemia In addition, many episodes of transient AF during hospital course are short-lived (<48 hours) and may be less likely to be associated with thrombus formation and stroke Thus, it remains uncertain whether transient AF episodes are associated with a subsequent increased risk of ischemic stroke, and whether they should be considered an indication for OAC

6 Aim The aim of this study was to investigate whether transient, new-onset AF during hospitalization for acute MI is associated with a risk of ischemic stroke and transient ischemic attack (TIA)

7 Methods We performed a retrospective analysis of patients admitted to our ICCU between 2000 and 2009 Exclusion criteria included: 1) Previously known AF or atrial flutter including paroxysmal AF 2) AF present at hospital discharge 3) Presence of left ventricular thrombus 4) In-hospital mortality

8 Patient monitoring and definition of AF Transient AF was defined as the occurrence of AF as an in-hospital complication, in the absence of a history of persistent or paroxysmal AF or atrial flutter Clinically indicated termination of the arrhythmia with pharmacological agents or DC cardioversion did not change the diagnosis of transient AF if done within the index hospitalization and the patient was discharged in sinus rhythm The total duration of transient AF was estimated as the time from onset of the arrhythmia to time of conversion to sinus rhythm in the hospital (either spontaneously, pharmacologically or electrical cardioversion)

9 Study endpoints The primary outcome of interest was a composite of ischemic stroke and TIA during a follow-up period of 1-year Ischemic stroke was defined as a neurologic deficit of sudden onset that persisted for more than 24 hours, corresponded to a vascular territory in the absence of primary hemorrhage, and was corroborated by an imaging study when possible TIA was diagnosed when symptoms lasted <24 hours with no cerebral infarction Stroke or TIA events were adjudicated by a neurologist based on a review of all relevant medical records and imaging studies

10 Study endpoints A secondary endpoint was the development of recurrent or new onset AF during a follow-up period of 1-year Transient postoperative AF, occurring as an isolated episode within one month after bypass surgery, was not considered as an outcome event Following hospital discharge, the ascertainment of AF was accomplished through review of the medical records and ECG tracings of each patient.

11 RESULTS Between January 2000 and May 2009, a total of 2763 patients who presented with AMI were identified Patients were excluded due to previously known AF or AF at hospital discharge (n = 95), echocardiographic evidence for a left ventricular thrombus (n = 49) and in-hospital death (n = 217). The remaining 2402 patients consisted the study population During hospital course 174 patients (7.2%) developed new-onset transient AF Transient AF lasting 24h and >24h occurred in 81 and 93 patients, respectively.

12 Baseline patient characteristics Transient AF Characteristics No (n = 2228) Yes (n = 174) P value Age (years) 60 ± ± 12 < Women 448 (20) 57 (33) < Previous infarction 450 (20) 37 (21) 0.74 Hypertension 1076 (48) 111 (64) < Current Smoker 415 (19) 39 (23) 0.21 Diabetes mellitus 617 (28) 53 (31) 0.44 creatinine (mg/dl) 1.0 ± ± 0.8 < Killip Class >I 424 (19) 67 (39) < Anterior infarction 957 (43) 82 (47) 0.29

13 Baseline patient characteristics Transient AF Characteristics No (n = 2228) Yes (n = 174) P value Bare-metal stent 955 (43) 63 (36) 0.09 Drug-eluting stent 112 (5) 2 (1) 0.02 CABG 50 (2) 6 (3) 0.31 LVEF (%) 46 ± ± 13 < Left atrial dimension 4.0 ± ± Aspirin 2189 (98) 166 (95) Dual antiplatelet therapy 1419 (64) 83 (48) < Oral anticoagulants 99 (4) 32 (18) < ACE inhibitors/arbs 1915 (86) 144 (83) 0.25

14 Cumulative incidence of stroke or TIA Log rank P < Transient AF (9.2%) 0.05 No AF (2.6%) 0.00 Number at Risk: Time (Days) No AF: Transient AF:

15 Cox regression model for Stroke/TIA at 1 year Unadjusted Adjusted Variable Hazard Ratio P value Hazard Ratio P value Age (per 10 y) 1.34 ( ) Female gender 1.95 ( ) Diabetes mellitus 1.98 ( ) ( ) 0.02 Killip class > I 2.88 ( ) < ( ) LVEF < 45% 2.00 ( ) Transient AF 3.66 ( ) < ( ) <0.0001

16 Antithrombotic treatment and clinical outcome At hospital discharge, of the 174 patients with transient AF, 142 (81.6%) were treated with antiplatelet therapy (aspirin or DAT) and 32 (18.4%) with OAC (with or without an antiplatelet agent) The CHADS 2 (2.0 ± 1.4 vs. 2.5 ± 1.3, P = 0.06) and the CHA 2 DS 2 VASc (4.0 ± 1.9 vs. 4.6 ± 1.6, P = 0.08) stroke risk scores were not significantly different in patients with and without OAC therapy Of the 61 transient AF patients with CHADS 2 stroke risk score 2, only 6 (9.8%) received OAC therapy.

17 Antithrombotic treatment and clinical outcome Transient AF/Antiplatete agents (9.9%) Transient AF/OAC (6.3%) 0.00 Number at risk No Transient AF (2.6%) Time (Days) After adjustments, compared with patients without AF, the adjusted HR for stroke or TIA was 3.28 in patients receiving antiplatelet agents (95% CI , P < ) and 1.97 in patients receiving OAC (95% CI ; P = 0.35).

18 AF After Hospital Discharge Log rank P < Transient AF (22.8%) Number at Risk: Time (Days) No AF (2.0%) No AF: Transient AF:

19 Conclusions Transient brief episodes of AF occurring during the acute phase of myocardial infarction are associated with an increased risk for subsequent ischemic stroke or TIA The risk is particularly elevated in patients treated with a single antiplatelet agent or with dual antiplatelet therapy Transient AF is a powerful predictor of recurrent AF after hospital discharge, further emphasizing the need to consider oral anticoagulants in these patients

20 Thank You for your Attention!