Risk of Stroke and Recurrence After AF Ablation

Abstract and Introduction

Abstract

Stroke and Recurrence After AF Ablation. Introduction: Because of the unclear prognostic effects of ablation of atrial fibrillation (AF), oral anticoagulation (OAC) is often continued after ablation even in asymptomatic patients. We sought to determine the frequency of stroke and AF recurrence in patients on and off therapeutic OAC 1 year after a successful AF ablation.

Methods and Results: Patients that underwent AF ablation and were free of AF 12 months after ablation were selected from our AF database. During follow-up (FU), patients were screened for recurrence of AF, changes in OAC or antiarrhythmic medication, and the occurrence of stroke or transient ischemic attack (TIA). A total of 398 patients (median age 60.7 years [50.8, 66.8], 25% female) were investigated. The median duration of FU was 529 (373, 111,3.5) days. OAC was discontinued in 276 patients (69.3%). During FU, 4 patients (1%) suffered from stroke and 55 patients (13.8%) experienced a recurrence of AF. Persistent AF was significantly associated with a greater chance of AF recurrence (49.1% vs. 26.8%; P = 0.001). Neither CHADS₂ nor CHA2DS2-VASc-Score nor recurrence of AF were significantly different in patients with or without stroke. There was a trend toward a higher percentage of coronary artery disease among patients that experienced stroke (50% vs. 10%; P = 0.057).

Conclusion: The overall risk of stroke and AF recurrence is low in patients with a recurrence free interval of at least 12 months after AF ablation. Of note, recurrence of AF was not associated with a higher risk of stroke in our study population.

Introduction

Ablation has become an important part of the treatment of atrial fibrillation (AF). Because of the lack of prospective data supporting a prognostic effect of AF ablation, it is still a procedure performed to improve quality-of-life in patients with symptomatic AF.^[1]

Several retrospective studies have indicated that AF ablation might also be beneficial in terms of mortality^[2–4] and for reducing the risk of stroke.^[5–11] Since stroke is the one of the most feared complications of AF, the influence of AF ablation on reducing the long-term risk of stroke is of significant interest.

However, other studies have shown that patients may continue to have asymptomatic episodes of AF after apparently successful ablation.^[12,13] Asymptomatic recurrence of AF is an important reason why oral anticoagulation (OAC) is not discontinued postablation in higher risk patients.^[1]

In addition to other important risk factors influencing the individual patient's risk for thromboembolism like left atrial appendage anatomy,^[14,15] a successful ablation of AF would seem to be an important requirement for any consideration of discontinuing OAC.^[16,17] However, the definition of a successful ablation is difficult. While some studies have examined the incidence of stroke postablation, most have looked at the entire postablation period starting from day 1, although the risk of AF recurrence is significantly lower in patients with an initial event-free period of 1 year or more.^[18] Thus, it seems reasonable to investigate such patients separately from those with earlier recurrences of AF.

Therefore, we sought to study the rate of stroke and recurrence of AF as well as the effects of discontinuation of anticoagulation in patients that were free from AF for at least 12 months after their last AF ablation.

Table 1. Patient Characteristics Stratified by AF/AT Recurrence
	All Patients	Recurrence	No Recurrence	P
n (%)	398	55 (13.8%)	343 (86.2%)
Follow-up in days	528.5 (373, 111,3.5)	1,471 (1,007, 1,935)	455 (367, 851)	<0.001
Persistent AF	119 (29.9%)	27 (49.1%)	92 (26.8%)	0.001
Age	60.7 (50.8, 66.8)	62.5 (52, 66.6)	60.1 (50.7, 67)	0.36
Female	98 (24.6%)	14 (25.5%)	84 (24.5%)	0.88
Hypertension	196 (49.2%)	27 (49.1%)	182 (53.1%)	0.58
Diabetes	49 (12.3%)	11 (20%)	38 (11.1%)	0.062
Hx of stroke/TIA	16 (4%)	1 (1.8%)	15 (4.4%)	0.37
Vascular disease	12 (3%)	1 (1.8%)	11 (3.2%)	0.7
Heart failure	29 (7.3%)	4 (7.3%)	25 (7.3%)	1
Hyperlipidemia	172 (43.2%)	20 (36.4%)	152 (44.3%)	0.27
Hx of smoking	56 (14.1%)	7 (12.7%)	49 (14.3%)	0.41
CAD	42 (10.6%)	5 (9.1%)	37 (10.8%)	0.82
CHADS₂-score	0.85 (±0.9)	0.85 (±0.93)	0.85 (±0.9)	0.97
CHA₂DS₂-VASc-score	1.46 (±1.28)	1.53 (±1.32)	1.45 (±1.28)	0.65
AAD discontinued	369 (92.7%)	54 (98.2%)	315 (91.3%)	0.16
OAC discontinued	276 (69.3%)	36 (65.5%)	240 (70%)	0.5
Months to recurrence		25.5 (17, 42)
Number of ablation procedures	1.1 (±0.3)	1.09 (±0.3)	1.15 (±0.4)	0.34

Hx = history; CAD = coronary artery disease; TIA = transient ischemic attack.

Table 2. Distribution of CHADS ₂- and CHA ₂DS ₂-VASc-Scores in the Study Population and Expected Stroke Rates for Each Score Level
	n	Expected Stroke rate (%/year)	AAD Discontinued	OAC Discontinued
CHADS₂
0	166 (41.2%)	1.9%	158 (95.2%)	146 (88%)
1	153 (38.4%)	2.8%	144 (94.1%)	110 (71.9%)
2	57 (14.3%)	4.0%	47 (82.5%)	17 (29.8%)
3	18 (4.5%)	5.9%	17 (94.4%)	3 (16.7%)
4	4 (1%)	8.5%	3 (75%)	0
CHA₂DS₂-VASc
0	108 (27.1%)	0	102 (94.4%)	101 (93.5%)
1	121 (30.4%)	1.3%	114 (94.2%)	98 (81%)
2	84 (21.1%)	2.2%	79 (94%)	53 (63.1%)
3	58 (14.6%)	3.2%	52 (89.7%)	20 (34.5%)
4	20 (5%)	4.0%	16 (80%)	4 (20%)
5	5 (1.3%)	6.7%	4 (80%)	0
6	2 (0.5%)	9.8%	2 (100%)	0

Table 3. Univariate Analysis for AF/AT Recurrence
	Odds Ratio	95% Confidence Interval	P
Persistent AF	2.63	1.47–4.7	0.001
Age	1.012	0.99–1.04	0.39
Female	1.05	0.55–2.03	0.88
Hypertension	0.85	0.48–1.51	0.58
Diabetes	2.01	0.96–4.21	0.066
Hx of Stroke/TIA	0.4	0.05–3.11	0.38
Vascular disease	0.44	0.06–3.47	0.43
Heart failure	1	0.33–2.99	0.997
Hyperlipidemia	0.718	0.4–1.29	0.27
Hx of smoking	0.69	0.29–1.67	0.41
CAD	0.83	0.31–2.21	0.7
AAD discontinued	4.8	0.64–36.02	0.13

Hx = history; CAD = coronary artery disease; TIA = transient ischemic attack.

Table 4. Stratification of Patients According to the CCS 2016, AHA 2014, and ESC 2016 Recommendation for Anticoagulation
CCS 2016 Recommendation	n	AAD Discontinued	OAC Discontinued	Recurrence
OAC	262 (65.8%)	241 (92%)	152 (58%)	36 (13.7%)
ASA	8 (2%)	5 (62.5%)	5 (62.5%)	0
No anticoagulation	128 (32.2%)	123 (96.1%)	119 (93%)	19 (14.8%)
AHA 2014 recommendation
OAC indicated (CHA₂DS₂-VASC ≥2)	168 (42.2%)	152 (90.5%)	76 (45.2%)	25 (14.9%)
OAC should be considered (CHA₂DS₂-VASC 1)	122 (30.7%)	99 (81.1%)	115 (94.3%)	14 (11.5%)
No anticoagulation (CHA₂DS₂-VASC 0)	108 (27.1%)	101 (93.5%)	102 (94.4%)	16 (14.5%)
ESC 2016 recommendation
OAC indicated (CHA₂DS₂-VASC ≥2 for male ≥3 for female patients)	139 (34.9%)	124 (89.2%)	50 (36%)	23 (16.5%)
OAC should be considered (CHA₂DS₂-VASC 1 for male and 2 for female patients)	125 (31.4%)	117 (93.6%)	101 (80.8%)	12 (9.6%)
No anticoagulation (CHA₂DS₂-VASC 0 or only female)	134 (33.7%)	128 (95.5%)	125 (93.3%)	20 (14.9%)

ASA = acetylsalicylic acid; OAC = oral anticoagulation.

Table 5. Characteristics of Patients That Suffered from Stroke/TIA
A. General Characteristics of Patients Suffering from Stroke or TIA
#	Age/Sex	CHADS₂-Score	CHA₂DS₂-VASc-Score	Months to Stroke/TIA	OAC at Time of Stroke/TIA		Recurrence of AF/AT Prior to Stroke
1	58/M	0	0	8	Coumadin		No
2	71/M	0	1	44	Warfarin		No
3	71/F	1	3	51	Discontinued		Yes
4	58/F	2	3	1	Dabigatran		No
B. Detailed Distribution of the CHADS₂- and CHA₂DS₂-VASc-Score Components for Patients Suffering from Stroke or TIA
#	Female Gender	Age >65	Age >75	Hypertension	Diabetes	Hx of prior Stroke or TIA	Heart Failure	Vasc. Disease
1	No	No	No	No	No	No	No	No
2	No	Yes	No	No	No	No	No	No
3	Yes	Yes	No	Yes	No	No	No	No
4	Yes	No	No	Yes	Yes	No	No	No

OAC = oral anticoagulation; TIA = transient ischemic attack.

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Risk of Stroke and Recurrence After AF Ablation in Patients With an Initial Event-Free Period of 12 Months

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