Cryoballoon vs RF Ablation in Paroxysmal Atrial Fibrillation
Cryoballoon vs RF Ablation in Paroxysmal Atrial Fibrillation
A total of 3,775 patients were included, with a mean age of 63 (54–69) years; 2,381 (63.1%) of them were males. The proportion of males was similar in both the RF and cryoballoon group (62.7% vs 64.3%; P = 0.38). Comorbidities and the rates of structural heart diseases were similar in both groups, and no statistical differences were found in baseline clinical characteristics (Table 1). A total of 92.9% of cryoballoon and 91.4% of RF ablation treated patients had normal LVEF (P = 0.17); 1.2% of cryoballoon patients but 2.4% of RF patients showed a reduced LVEF (≤40%) (P<0.05). History of symptomatic AF and palpitations was similar in both groups; the SAF score analysis is shown in Table 2. The SAF scale has been validated to qualify AF related symptoms and their functional consequences on patient's daily life with respect to AF documentation and therapy. The SAF score is rated on a scale from 0 (asymptomatic) to 4 (severe impact of symptoms on the quality of life) Frequent AF episodes (≥1 episode per month, 93.2% vs 90.2%; P < 0.01) and drug resistant AF episodes (94.0% vs 71.6%; P < 0.0001) were more frequent in patients undergoing RF ablation.
In 1.8% of patients undergoing cryoablation and 1.1% undergoing RF ablation a second arrhythmia apart from AF was present (P = 0.13).
The majority of patients in Germany have been ablated in more experienced centers performing >200 ablations per year, with 69.2% of the RF patients and 67.5% of the patients undergoing cryoablation (P = 0.18). AF ablation was performed more frequently in sinus rhythm using cryoablation (88.1%) compared to RF ablation (82.5%; P < 0.001).
In RF ablation, most commonly the 3.5 mm irrigated tip electrode (83.4%), in 5% irrigated tip catheters of other length, in 12% nonirrigated 4 mm tip catheters and in 1% 8 mm tip catheters were used. During cryoablation, the cryoballoon catheter was used in all patients, with additional use of the cryo-tip catheter in 10.6% of the patients.
In RF ablation 3.1 ± 0.8 transvenous sheaths were used vs 2.5 ± 1.1 in cryoablation (P < 0.0001). An arterial sheath was used more often in cryoablation (65.6% vs 25.6% in RF ablation; P < 0.0001). More transseptal access and sheaths were used in RF than in cryoablation (1.8 ± 0.4 vs 1.2 ± 0.4; P < 0.0001).
Conventional mapping was more common in cryoablation (67.6% vs 28.5% in RF ablation, P < 0.0001), whereas 3D electroanatomical mapping was favored in RF ablation (71.2% vs 25.4% in cryoablation, P < 0.0001). Preprocedural imaging was performed more frequently in cryoablation (43.5%) using cardiac MRI in 3.8%, cardiac CT in 32.0% and ICE in 7.7% compared to RF ablation (25.2%) using cardiac MRI in 3.4%, cardiac CT in 21.0% and ICE in 2.5%.
Mean total procedure time was similar with both ablation methods (160 minutes in cryoablation vs 165 minutes in RF ablation; P = 0.39). Mean ablation time was longer in cryo than in RF ablation and also fluoroscopy time and radiation dose per ablation were significantly higher in cryoablation compared to RF ablation (Table 3).
Antiarrhythmic agents: At time of discharge, 48.0% of patients after cyroablation and 56.2% of patients after RF ablation were on antiarrhythmic drugs (P < 0.0001); 25.1% of the patients undergoing cryoablation were on class I antiarrhythmics compared to 33.1% of the patients undergoing RF ablation (P < 0.0001); class III antiarrhythmic drugs were used similarly in both groups (21.3% in cryoablation and 20.6% in RF ablation; P = 0.67) (Table 4).
Anticoagulation: Phenprocoumon was less common in patients at discharge after cryoablation (85.0%) compared to RF ablation (90.5%; P < 0.0001), antithrombotic agents were used in 14.3% after cryo- and in 11.9% after RF ablation (P = 0.06), and low molecular weight heparin was used in 54.1% of patients after cryoablation compared to 67.1% of patients after RF ablation (P < 0.0001).
Acute success rates were similar in both groups (97.5% in cryo vs 97.6% in RF; P = 0.92). Mean duration of hospital stay was shorter in patients undergoing RF ablation (3 [2–5] vs 4 [3–6] days; P < 0.0001). AF recurrence rates until discharge were similar after cryo (5.9%) and RF ablation (5.6%; P = 0.81).
Procedural MACCE was similar in both groups (0.4% in cryo vs 0.2% in RF; P = 0.15). Overall complication rate was similar in cryo (4.6%) and RF ablation (4.6%; P = 1.0). Phrenic nerve palsy was more often in cryo vs RF ablation (2.1% in cryo vs 0.0% in RF; P < 0.001). The procedural complication rate excluding phrenic nerve palsy was higher in RF versus cryoablation (4.6% in RF vs 2.7% in cryo; P < 0.05, Table 5). Also, minor bleedings not requiring interventions were more common in RF ablation (3.8% in RF vs 2.3% in cryo; P < 0.05). In both groups, a pacemaker had to be implanted in 0.2% of patients after the AF ablation procedure (P = 0.90). All patients left the hospital post-AF ablation; there were no procedure related deaths.
Results
Baseline Characteristics
A total of 3,775 patients were included, with a mean age of 63 (54–69) years; 2,381 (63.1%) of them were males. The proportion of males was similar in both the RF and cryoballoon group (62.7% vs 64.3%; P = 0.38). Comorbidities and the rates of structural heart diseases were similar in both groups, and no statistical differences were found in baseline clinical characteristics (Table 1). A total of 92.9% of cryoballoon and 91.4% of RF ablation treated patients had normal LVEF (P = 0.17); 1.2% of cryoballoon patients but 2.4% of RF patients showed a reduced LVEF (≤40%) (P<0.05). History of symptomatic AF and palpitations was similar in both groups; the SAF score analysis is shown in Table 2. The SAF scale has been validated to qualify AF related symptoms and their functional consequences on patient's daily life with respect to AF documentation and therapy. The SAF score is rated on a scale from 0 (asymptomatic) to 4 (severe impact of symptoms on the quality of life) Frequent AF episodes (≥1 episode per month, 93.2% vs 90.2%; P < 0.01) and drug resistant AF episodes (94.0% vs 71.6%; P < 0.0001) were more frequent in patients undergoing RF ablation.
In 1.8% of patients undergoing cryoablation and 1.1% undergoing RF ablation a second arrhythmia apart from AF was present (P = 0.13).
Ablation Procedure
The majority of patients in Germany have been ablated in more experienced centers performing >200 ablations per year, with 69.2% of the RF patients and 67.5% of the patients undergoing cryoablation (P = 0.18). AF ablation was performed more frequently in sinus rhythm using cryoablation (88.1%) compared to RF ablation (82.5%; P < 0.001).
In RF ablation, most commonly the 3.5 mm irrigated tip electrode (83.4%), in 5% irrigated tip catheters of other length, in 12% nonirrigated 4 mm tip catheters and in 1% 8 mm tip catheters were used. During cryoablation, the cryoballoon catheter was used in all patients, with additional use of the cryo-tip catheter in 10.6% of the patients.
In RF ablation 3.1 ± 0.8 transvenous sheaths were used vs 2.5 ± 1.1 in cryoablation (P < 0.0001). An arterial sheath was used more often in cryoablation (65.6% vs 25.6% in RF ablation; P < 0.0001). More transseptal access and sheaths were used in RF than in cryoablation (1.8 ± 0.4 vs 1.2 ± 0.4; P < 0.0001).
Conventional mapping was more common in cryoablation (67.6% vs 28.5% in RF ablation, P < 0.0001), whereas 3D electroanatomical mapping was favored in RF ablation (71.2% vs 25.4% in cryoablation, P < 0.0001). Preprocedural imaging was performed more frequently in cryoablation (43.5%) using cardiac MRI in 3.8%, cardiac CT in 32.0% and ICE in 7.7% compared to RF ablation (25.2%) using cardiac MRI in 3.4%, cardiac CT in 21.0% and ICE in 2.5%.
Mean total procedure time was similar with both ablation methods (160 minutes in cryoablation vs 165 minutes in RF ablation; P = 0.39). Mean ablation time was longer in cryo than in RF ablation and also fluoroscopy time and radiation dose per ablation were significantly higher in cryoablation compared to RF ablation (Table 3).
Medication
Antiarrhythmic agents: At time of discharge, 48.0% of patients after cyroablation and 56.2% of patients after RF ablation were on antiarrhythmic drugs (P < 0.0001); 25.1% of the patients undergoing cryoablation were on class I antiarrhythmics compared to 33.1% of the patients undergoing RF ablation (P < 0.0001); class III antiarrhythmic drugs were used similarly in both groups (21.3% in cryoablation and 20.6% in RF ablation; P = 0.67) (Table 4).
Anticoagulation: Phenprocoumon was less common in patients at discharge after cryoablation (85.0%) compared to RF ablation (90.5%; P < 0.0001), antithrombotic agents were used in 14.3% after cryo- and in 11.9% after RF ablation (P = 0.06), and low molecular weight heparin was used in 54.1% of patients after cryoablation compared to 67.1% of patients after RF ablation (P < 0.0001).
Efficacy
Acute success rates were similar in both groups (97.5% in cryo vs 97.6% in RF; P = 0.92). Mean duration of hospital stay was shorter in patients undergoing RF ablation (3 [2–5] vs 4 [3–6] days; P < 0.0001). AF recurrence rates until discharge were similar after cryo (5.9%) and RF ablation (5.6%; P = 0.81).
Safety
Procedural MACCE was similar in both groups (0.4% in cryo vs 0.2% in RF; P = 0.15). Overall complication rate was similar in cryo (4.6%) and RF ablation (4.6%; P = 1.0). Phrenic nerve palsy was more often in cryo vs RF ablation (2.1% in cryo vs 0.0% in RF; P < 0.001). The procedural complication rate excluding phrenic nerve palsy was higher in RF versus cryoablation (4.6% in RF vs 2.7% in cryo; P < 0.05, Table 5). Also, minor bleedings not requiring interventions were more common in RF ablation (3.8% in RF vs 2.3% in cryo; P < 0.05). In both groups, a pacemaker had to be implanted in 0.2% of patients after the AF ablation procedure (P = 0.90). All patients left the hospital post-AF ablation; there were no procedure related deaths.
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