Durability of Pulmonary Vein Isolation with Cryoballoon Ablation: Results from the Sustained PV Isolation with Arctic Front Advance (SUPIR) Study

On the Quest for the Best Freeze

Background—

The second-generation cryoballoon is effective in achieving acute pulmonary vein isolation (PVI) and favorable clinical outcome. To date, no data are available on factors affecting late PV reconnection after second-generation cryoballoon ablation.

Methods and Results—

A total of 29 consecutive patients (25 male, 86.2%; mean age 57.8±13.8 years) underwent a repeat procedure, after a mean 11.6±4.5 months (range, 3.5–19.7 months), after index ablation using the 28-mm second-generation cryoballoon. All repeat ablations were performed using a 3-dimensional electroanatomical mapping system. Among all 115 PVs, including 1 left common ostiums (LCOs), 25 (21.7%) showed a PV reconnection in 20 patients (1.25 per patient). Persistent PVI could be documented in 90 of 115 PVs (78.2%). In 9 of 29 patients (31%), all PVs were electrically isolated. In the multivariable analysis, time to PVI ( P =0.03) and failure to achieve −40°C within 60 s ( P =0.05) independently predicted late PV reconnection. At receiver-operator curve analysis, time to PVI <60 s identified the absence of PV reconduction (sensitivity, 86.7%; specificity, 86.2%; positive predictive value, 59.1%; and negative predictive value, 96.4%; area under the curve, 0.85; confidence interval, 0.73–0.97; P <0.001).

Conclusions—

The rate of late PV reconnection after second-generation cryoballoon ablation is low (1.25 PVs/patient). Faster time to isolation and achievement of −40°C within 60 s independently predict durable PVI. In addition, 60-s cut-off for time to PVI indicates persistent isolation with 96.4% negative predictive value. These parameters might guide the operator whether to perform further applications to ensure a long-lasting PVI.

Outcomes Of Cryoballoon Ablation Of Atrial Fibrillation: A Comprehensive Review

Over the last decade, cryoballoon ablation has emerged as an effective alternate strategy to point-by-point radiofrequency ablation for treatment of symptomatic atrial fibrillation. There are several reasons for this. First, the acute and long-term safety and efficacy associated with cryoablation appear comparable to that of radiofrequency ablation in patients with both paroxysmal and also persistent atrial fibrillation. Second, cryoablation offers certain advantages over conventional radiofrequency ablation including a gentler learning curve, shorter ablation and procedure times as well as lack of need for costly electroanatomical mapping technologies commonly utilized with radiofrequency ablation. Lastly, with the recent advent of the second-generation cryoballoon, the effectiveness of cryoablation has further improved dramatically. This comprehensive review examines the gradual evolution of the cryoablation tools as well as the rationale and data in support of the currently-available cryoballoon technologies for catheter ablation of atrial fibrillation.

Two-year outcome after pulmonary vein isolation using the second-generation 28-mm cryoballoon: lessons from the bonus freeze protocol

BACKGROUND

Pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB2) in patients with paroxysmal and persistent atrial fibrillation (AF) has demonstrated encouraging acute and mid-term results. Follow-up data on outcome beyond 1-year is lacking. The purpose of this analysis was to investigate the 2-year clinical outcome after CB2-based PVI.

METHODS

Sixty patients (age 62 ± 11 years) with paroxysmal [45/60 (75%) patients] or short-standing persistent AF [15/60 (25%) patients] underwent 28-mm CB2-based PVI. Freeze-cycle duration was 240 s. After successful PVI, a bonus freeze-cycle of the same duration was applied. Follow-up was based on outpatient clinic visits at 3, 6, 12, 18, and 24 months including 24 h Holter-ECGs and telephone interviews. Recurrence was defined as any symptomatic and/or documented atrial tachyarrhythmia (ATA) episode >30 s following a 3-month blanking period.

RESULTS

A total of 231 pulmonary veins (PV) were identified and 230/231 (99.6%) PVs were successfully isolated. Phrenic nerve palsy occurred in 2/60 (3.3%) patients. No other periprocedural complications occurred. Follow-up was available for 59/60 (98%) patients with a mean duration of 838 ± 67 days. A total of 43/59 (73%) patients remained in stable sinus rhythm. In 10/16 (63%) patients with ATA recurrence, a repeat procedure was performed using radiofrequency energy. The overall success rate after a maximum of two ablation procedures and a follow-up period of 838 ± 67 days was 88% (52/59) patients.

CONCLUSIONS

Patients with paroxysmal or short-persistent AF undergoing PVI using the 28-mm CB2 demonstrated a 73% 2-year single-procedure clinical success rate.

Acute and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using the Second-Generation Cryoballoon versus Open-Irrigated Radiofrequency: A Multicenter Experience

INTRODUCTION

There are limited comparative data on catheter ablation of atrial fibrillation (CAAF) using the second-generation cryoballoon (CB-2) versus point-by-point radiofrequency (RF). This study examines the acute/long-term CAAF outcomes using these 2 strategies.

METHODS AND RESULTS

In this multicenter, retrospective, nonrandomized analysis, procedural and clinical outcomes of 1,196 patients (76% with paroxysmal AF) undergoing CAAF using CB-2 (n = 773) and open-irrigated, non-force sensing RF (n = 423) were evaluated. Pulmonary vein isolation was achieved in 98% with CB-2 and 99% with RF (P = 0.168). CB-2 was associated with shorter ablation time (40 ± 14 min vs. 66 ± 26 min; P < 0.001) and procedure time (145 ± 49 minutes vs. 188 ± 42 minutes; P < 0.001), but greater fluoroscopic utilization (29 ± 13 minutes vs. 23 ± 14 minutes; P < 0.001). While transient (7.6% vs. 0%; P < 0.001) and persistent (1.2% vs. 0%; P = 0.026) phrenic nerve palsy occurred exclusively with CB-2, other adverse event rates were similar between CB-2 (1.6%) and RF (2.6%); P = 0.207. However, freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 (76.6%) versus RF (60.4%); P < 0.001. While this difference was evident in patients with paroxysmal AF (P < 0.001), it did not reach significance in those with persistent AF (P = 0.089). Additionally, CB-2 was associated with reduced long-term need for antiarrhythmic therapy (16.7% vs. 22.0%; P = 0.024) and repeat ablations (14.6% vs. 24.1%; P < 0.001).

CONCLUSION

In this multicenter, retrospective, nonrandomized study, CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated, non-force sensing RF, alone.