PLAAF score as a novel predictor of long-term outcome after second-generation cryoballoon pulmonary vein isolation

Clinical, Electrocardiographic and Echocardiographic Predictors of Atrial Fibrillation Recurrence After Pulmonary Vein Isolation

Atrial fibrillation (AF) is a supraventricular arrhythmia and the most common heart rhythm disorder in the adult population worldwide with an estimated prevalence of 2% to 4% of the population. Cases of AF have shown an increasing trend in recent decades, while its frequency is expected to rise even more. Given the significant impact on patients' quality of life, as well as its major complications, including thromboembolic events, effective rhythm control strategies other than antiarrhythmic medication have emerged, with catheter ablation (CA) being the cornerstone of these. In recent years, CA has been upgraded to a first-line treatment for selected patients. However, complications do exist and arrhythmia-free survival is not always guaranteed. The need to better identify patients more suitable for this specific therapeutic measure is crucial in improving outcomes and preventing arrhythmia recurrences. This review aims to present currently identified predictors of AF recurrence after catheter ablation based on clinical characteristics and electrocardiographic and echocardiographic parameters, in an era of increasing interventional rhythm control approaches for the management of atrial fibrillation.

Multidisciplinary management strategies for atrial fibrillation

There has been a significant increase in the prevalence of atrial fibrillation (AF) over the past 30 years. Pulmonary vein isolation (PVI) is an effective treatment for AF, but research investigations have shown that AF recurrence still occurs in a significant number of patients after ablation. Heart rhythm outcomes following catheter ablation are correlated with numerous clinical factors, and researchers developed predictive models by integrating risk factors to predict the risk of recurrence of atrial fibrillation. The purpose of this article is to outline the risk scores for predicting cardiac rhythm outcomes after PVI and to discuss the modifiable factors that increase the risk of recurrence of AF, with the hope of further improving catheter ablation efficacy through preoperative identification of high-risk populations and postoperative management of modifiable risk factors.

Sex-specific outcomes after catheter ablation for persistent AF

BACKGROUND

Sex-specific outcomes after catheter ablation (CA) for atrial fibrillation (AF) have reported conflicting findings.

OBJECTIVE

We examined the impact of female sex on outcomes in patients with persistent AF (PsAF) from the Catheter Ablation for Persistent Atrial Fibrillation: A Multicentre Randomized Trial of Pulmonary Vein Isolation vs PVI with Posterior Left Atrial Wall Isolation (CAPLA) randomized trial.

METHODS

A total of 338 patients with PsAF were randomized to pulmonary vein isolation (PVI) or PVI with posterior wall isolation (PWI). The primary outcome was arrhythmia recurrence at 12 months. Clinical and electroanatomical characteristics, arrhythmia recurrence, and quality of life were compared between women and men.

RESULTS

Seventy-nine women (23.4%; PVI 37; PVI + PWI 42) and 259 men (76.6%; PVI 131; PVI + PWI 128) underwent AF ablation. Women were older {median age 70.4 (interquartile range [IQR] 64.8-74.6) years vs 64.0 (IQR 56.7-69.7) years; P < .001} and had more advanced left atrial electroanatomical remodeling. At 12 months, arrhythmia-free survival was lower in women (44.3% vs 56.8% in men; hazard ratio 1.44; 95% confidence interval 1.02-2.04; log-rank, P = .036). PWI did not improve arrhythmia-free survival at 12 months (hazard ratio 1.02; 95% confidence interval 0.74-1.40; log-rank, P = .711). The median AF burden was 0% in both groups (women: IQR 0.0%-2.2% vs men: IQR 0.0%-2.8%; P = .804). Health care utilization was comparable between women (36.7%) and men (30.1%) (P = .241); however, women were more likely to undergo a repeat procedure (17.7% vs 6.9%; P = .007). Women reported more severe baseline anxiety (average Hospital Anxiety and Depression Scale [HADS] anxiety score 7.5 ± 4.9 vs 6.3 ± 4.3 in men; P = .035) and AF-related symptoms (baseline Atrial Fibrillation Effect on Quality-of-Life Questionnaire [AFEQT] score 46.7 ± 20.7 vs 55.9 ± 23.0 in men; P = .002), with comparable improvements in psychological symptoms (change in HADS anxiety score -3.8 ± 4.6 vs -3.0 ± 4.5; P = .152 (change in HADS depression score -2.9 ± 5.0 vs -2.6 ± 4.0; P = .542) and greater improvement in AFEQT score compared with men at 12 months (change in AFEQT score +45.9 ± 23.1 vs +39.2 ± 24.8; P = .048).

CONCLUSION

Women undergoing CA for PsAF report more significant symptoms and poorer quality of life at baseline than men. Despite higher arrhythmia recurrence and repeat procedures in women, the AF burden was comparably low, resulting in significant improvements in quality of life and psychological well-being after CA in both sexes.

Validation of the SCALE-CryoAF risk model to predict very late return of atrial fibrillation after cryoballoon ablation

BACKGROUND

To date, few risk models have been validated to predict recurrent atrial fibrillation (AF) >1 year after ablation. The SCALE-CryoAF score was previously derived to predict very late return of AF (VLRAF) >1 year following cryoballoon ablation (CBA), with strong predictive ability. In this study, we aim to validate the SCALE-CryoAF score for VLRAF after CBA in a novel patient cohort.

METHODS

Retrospective analysis of a prospectively maintained single-center database was performed. Inclusion criteria were pulmonary vein isolation using CBA 2017-2020. Exclusion criteria included prior ablation, <1-year follow-up, lack of pre-CBA echocardiogram, additional ablation lesion sets, and documented AF recurrence 90-365 days post-CBA. The area under the curve (AUC) of SCALE-CryoAF was compared to the derivation value and other established risk models.

RESULTS

Among 469 CBA performed, 241 (61% male, 62.8 ±11.7 years old) cases were included in analysis. There were 37 (15.4%) patients who developed VLRAF. Patients with VLRAF had a higher SCALE-CryoAF score (VLRAF 5.4 ± 2.7; no VLRAF 3.1 ± 2.9; p<0.001). SCALE-CryoAF was linearly associated with VLRAF (y=14.35x-11.72, R2=0.99), and a score > 5 had a 32.7% risk of VLRAF. The SCALE-CryoAF risk model predicted VLRAF with an AUC of 0.74, which was similar to the derivation value (AUCderivation: 0.73) and statistically superior to MB-LATER, CHA2DS2-VASc, and CHADS2 scores.

CONCLUSIONS

The current analysis validates the ability of SCALE-CryoAF to predict VLRAF after CBA in a novel patient cohort. Patients with a high SCALE-CryoAF score should be monitored closely for recurrent AF >1 year following CBA.

ECG-I Phenotyping of Persistent AF Based on Driver Burden and Distribution to Predict Response to Pulmonary Vein Isolation (PHENOTYPE-AF)

BACKGROUND

This prospective trial sought to phenotype persistent AF based on AF mechanisms using ECGI mapping to determine whether this would predict long term freedom from arrhythmia after pulmonary vein isolation (PVI).

METHODS

Patients with persistent AF of < 2 years duration underwent cryoballoon PVI. ECGI mapping was performed prior to PVI to determine potential drivers (PDs) defined as rotational activations completing ≥ 1.5 revolutions or focal activations. The co-primary end point was the association between (1) PD burden (defined as the number of PD occurrences) and (2) PD distribution (defined as the number of segments on an 18 segment model of the atria harbouring PDs) with freedom from arrhythmia at 1 year follow up.

RESULTS

Of 100 patients, 97 completed follow up and 52 (53.6%) remained in sinus rhythm off antiarrhythmic drugs. Neither PD burden nor PD distribution predicted freedom from arrhythmia (HR 1.01, 95% CI 0.99 - 1.03, p = 0.164; and HR 1.04, 95% CI 0.91 - 1.17, p = 0.591 respectively). Otherwise, the burden of rotational PDs, rotational stability, and the burden of PDs occurring at the pulmonary veins and posterior wall all failed to predict arrhythmia recurrence (all p > 0.10).

CONCLUSIONS

AF mechanisms as determined using ECGI mapping do not predict outcome after PVI for persistent AF. Further studies using different methodologies to characterise AF mechanisms are warranted. (NCT03394404) This article is protected by copyright. All rights reserved.

Variations in human pulmonary vein ostia morphology: A systematic review with meta-analysis

This study aimed to establish the most accurate and up-to-date anatomical knowledge of pulmonary veins (PV), ostia variations, diameters and ostial area, to provide physicians, especially heart and thoracic surgeons with exact knowledge concerning this area. The main online medical databases, such as PubMed, Embase, Scopus, Web of Science, and Google Scholar, were searched to gather all studies in which the variations, maximal diameter, and ostial area of the PVs were investigated. During the study, the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. Additionally, the critical appraisal tool for anatomical meta-analysis (CATAM) was used to provide the highest quality findings. The most common ostia variation is the classical one, which contains the left superior pulmonary vein (LSPV), left inferior pulmonary vein (LIPV), right superior pulmonary vein (RSPV) and right inferior pulmonary vein (RIPV). The mean diameter and ostial area of each pulmonary vein were established in the general population and in multiple variations considering the method of collecting the data and geographical location. Significant variability in PV ostia is observed. Left-sided PVs have smaller ostia than the corresponding right-sided PVs, and the inferior PVs ostia are smaller than the superior. The LCPV ostium size is the largest among all veins analyzed, while the RMPV ostium is the smallest. The results of this meta-analysis are hoped to help clinicians in planning and performing procedures that involve the pulmonary and cardiac areas, especially catheter ablation for atrial fibrillation.

How effective is cryoablation in the treatment of atrial fibrillation?

Pulmonary vein isolation is the standard for atrial fibrillation ablation. Although the most commonly applied energy source is radiofrequency (RF), cryoablation has rapidly evolved as a powerful one-shot tool, particularly after the introduction of the second-generation catheter, gaining widespread use in recent years. The efficacy in maintaining sinus rhythm after a first ablative procedure is ∼70–80%, and the randomization studies comparing cryoablation to RF have not been able to reveal significant differences up to now. Although different baseline characteristics may influence the efficacy of cryoablation, we are not yet able to distinguish which patients may benefit from a personalized choice of ablative source. Regarding safety, cryoballoon ablation appears to be associated with a lower rate of pericardial effusion and cardiac tamponade, mainly due to the lack of risk of overheating. The other side of the coin is a higher incidence of phrenic nerve damage, which occurs in 1–2% of procedures. In conclusion, we do not yet have definitive data to affirm the superiority of the RF technique over that of cryoablation. The choice of energy source currently depends on the availability of the centre and on the experience of the operator.

Comparison of six risk scores for the prediction of atrial fibrillation recurrence after cryoballoon-based ablation and development of a simplified method, the 0-1-2 PL score

INTRODUCTION

There are several prognostic scores for the assessment of risk of atrial fibrillation (AF) recurrence post ablation procedure. However, the use of these complex scores is difficult and the validation on different populations brought divergent results. Our goal was to compare the performance of these risk scores as the basis for the development of a new, simplified score based only on few universally predictive variables.

METHODS

All cryoballoon-based AF ablations performed in a single-center over a 10-year period were prospectively analyzed with regard to AF recurrence. This served to analyze the performance of APPLE, CAAP-AF, SCALE-CryoAF, MB-LATER, CHADS2, and CHA2DS2-VASc risk scores.

RESULTS

A total of 597 patients, mostly (78.1%) with paroxysmal AF were studied. Analyzed risk scores performed poorer than in the original publications because some risk factors were not predictive of AF recurrence. A simplified score named 0-1-2 PL, composed of just two universally predictive variables, AF type (1 point for Persistent AF) and LA dimension (1 point for LA size >45 mm) was developed. The 0-1-2 PL score stratified patients into low risk (0 points), intermediate risk (1 point), and high risk categories (2 points) which were related to a 2-year risk of AF recurrence of 21%, 37%, and 55%, respectively. This score had C-statistics (0.620) higher/comparable to other investigated much more complex scores.

CONCLUSION

The assessment of risk of AF recurrence at the pre-ablation stage can be simplified without compromising accuracy. This could help to popularize risk assessment and standardization of AF management.

A novel risk model for very late return of atrial fibrillation beyond 1 year after cryoballoon ablation: the SCALE-CryoAF score

PURPOSE

Cryoballoon ablation (CBA) is an effective technique for pulmonary vein isolation (PVI). To date, there are no risk models to predict very late recurrence of atrial fibrillation (VLRAF) after CBA.

METHODS

Retrospective analysis of a single-center database was performed. Inclusion criteria included PVI using CBA for atrial fibrillation (AF) without additional ablation targets, follow-up > 365 days, and no recurrent AF between 90 and 365 days after procedure. The primary endpoint was recurrent AF > 30 s > 12 months post-CBA. A risk model was created using clinical variables.

RESULTS

Of 674 CBA performed from 2011 to 2016, 300 patients (200 male, 62.0 ± 9.9 years) met inclusion criteria. Of these, 159 (53.0%) patients had paroxysmal AF. Patients had an average of 9.5 ± 2.7 cryoballoon freezes, and no patients required additional radiofrequency ablation lesion sets. Over a follow-up of 995 ± 490 days, 77/300 (25.7%) patients exhibited VLRAF. Univariate and multivariate analyses demonstrated that Structural heart disease (1 point), Coronary artery disease (3 points), left Atrial diameter > 43 mm (1 point), Left bundle branch block (3 points), Early return of AF (4 points), and non-paroxysmal AF (3 points) were risk factors for VLRAF. Combining these variables into a risk model, SCALE-CryoAF, (min 0; max 15) predicted VLRAF with an area under the curve of 0.73.

CONCLUSION

SCALE-CryoAF is the first risk model to specifically predict first recurrence of AF beyond 1 year, VLRAF, after CBA. Model discrimination demonstrates that SCALE-CryoAF predicts VLRAF after CBA significantly better than other risk models for AF recurrence.

Evaluation of predictive scores for late and very late recurrence after cryoballoon-based ablation of atrial fibrillation

Purpose

Studies on predictive scores for very late recurrence (VLR) (recurrence later than 12 months) after second-generation cryoballoon-based pulmonary vein isolation (CB2-PVI) are sparse. We aimed to evaluate the frequency of late recurrence (LR) (later than 3 months) and VLR, and to validate predictive scores for LR and VLR after initial CB2-PVI.

Methods

A total of 288 patients undergoing initial CB2-PVI (66 ± 11 years, 46% paroxysmal) were retrospectively enrolled in the LR cohort. In the VLR cohort, 83 patients with recurrence within 3–12 months or with < 12-month follow-up were excluded. The predictive scores of arrhythmia recurrence were assessed, including the APPLE, DR-FLASH, PLAAF, BASE-AF₂, ATLAS, SCALE-CryoAF, and MB-LATER scores.

Results

During a mean follow-up of 15.3 ± 7.1 months, 188 of 288 (65.2%) patients remained in sinus rhythm without any recurrences. Thirty-two of 205 (15.6%) patients experienced VLR after a mean of 16.6 ± 5.6 months. Comparing the predictive values of these specific scores, the MB-LATER score showed a reliable trend toward greater risk of both LR and VLR (area under the curve in LR; 0.632, 0.637, 0.632, 0.637, 0.604, 0.725, and 0.691 (p = ns), VLR; 0.612, 0.636, 0.644, 0.586, 0.541, 0.633, and 0.680 (p = 0.038, vs. BASE-AF₂, respectively)). Kaplan-Meier analysis estimated patients with higher MB-LATER scores which had favorable outcomes (24-month freedom from LR; 26.0% vs. 56.7%, p < 0.0001, VLR; 53.4% vs. 82.1%, p = 0.013).

Conclusion

The MB-LATER score provided more reliable predictive value for both LR and VLR. Patients with higher MB-LATER scores may benefit from more intensive long-term follow-up.

Left Atrial Volume Index Predicts Arrhythmia-Free Survival in Patients with Persistent Atrial Fibrillation Undergoing Cryoballoon Ablation

Background

Pulmonary vein isolation (PVI) using cryoballoon ablation (PVI-C) is increasingly performed as a first-line strategy for the treatment of patients with persistent atrial fibrillation (PersAF); however, follow-up data and predictors of procedural success are lacking.

Objective

To study the efficacy of PVI-C in patients with PersAF, focusing on predictors of procedural success.

Methods

By retrospective review, 148 consecutive patients with PersAF who underwent PVI-C were analyzed. The impact of several variables on outcome was evaluated in univariate and multivariate analyses and Cox proportional hazards regression models.

Results

After a mean follow-up of 19.2±10.9 months, 75 (50.7%) patients remained arrhythmia-free without the need for antiarrhythmic drug therapy. Patients with a normal left atrial volume index (LAVI) achieved a 71.0% arrhythmia-free survival. LAVI was the most powerful predictor of procedural success.

Conclusions

Arrhythmia-free survival after PVI-C in select patients with PersAF are promising. Moreover, LAVI is a valuable measurement to help guide ablation strategy and predict outcome when using cryoballoon ablation.

Stratifying risk of recurrence of atrial fibrillation following balloon cryoablation using the CAAP-AF risk scoring system

OBJECTIVE

To determine if the CAAP-AF tool could be applied to a cohort of patients in the United States undergoing cryoablation or AF utilizing second-generation cryoballoons.

BACKGROUND

Atrial fibrillation (AF) is a major source of morbidity and expense, with over 33 million individuals affected worldwide and over 450 000 hospitalizations annually in the United States. Catheter ablation for AF is a class I indication for patients with symptomatic AF. The ability to predict postablation recurrence would have an enormous impact on both patient outcomes and cost to the health care system.

METHODS

Our study was an observational, single-center retrospective study to evaluate the utility of the CAAP-AF risk scoring system in predicting recurrence of AF following second-generation balloon cryoablation for AF.

RESULTS

There were a total of 235 patients. From the initial cohort, 30.2% (71) had a recurrence of AF within 1 year of the cryoablation procedure. There was a statistically significant increase in mean age, left atrial diameter, left atrial volume index, CHADS₂ , CHADS₂ -VASc, and number of antiarrhythmics failed in the group that had recurrence of AF. There was also a statistically significant increase in the CAAP-AF score in patients who had recurrence of AF.

CONCLUSIONS

The CAAP-AF score predicted the freedom from AF 1 year following cryoablation for AF. The CAAP-AF score can aid in selecting patients most likely to benefit from cryoablation, which includes patients with a low CAAP-AF score, as they are most likely to remain AF free at 1 year.

Patient characteristics as predictors of recurrence of atrial fibrillation following cryoballoon ablation

BACKGROUND

While several studies have evaluated predictors for atrial fibrillation (AF) recurrence following catheter ablation, there are limited data specific to cryoballoon ablation (CBA).

METHODS

We analyzed a prospective registry of patients at a single institution who underwent CBA. Recurrence of AF (RAF) was defined as recurrence of AF by 12-month follow-up, excluding the 3-month blanking period. Univariate analysis was performed to evaluate predictors of RAF. Receiver operating characteristic analysis was used to compare and evaluate the performance of various risk scores for discriminating risk of RAF.

RESULTS

There were 542 patients included in the analysis with mean age 61.3 ± 10.6 years, 67.9% male, and 51.6% paroxysmal AF (PAF). Overall, only left atrial diameter (LAD) > 40 mm and ERAF (early recurrence of AF within 0-3 month blanking period) were significant predictors of RAF. In the PAF specific subgroup, LAD > 40 mm, AF duration > 12 months, prior stroke or transient ischemic attack, ERAF, and having previously failed an antiarrhythmic drug were significant predictors of RAF. In persistent AF (PeAF) subgroup, obstructive sleep apnea (OSA) and ERAF were significant predictors of RAF. Out of clinical risk scores tested, BASEAF2 had the highest performance with area under the curve of 0.646 (95% confidence interval [0.548, 0.708]; P < .01).

CONCLUSIONS

In this single-center retrospective study of CBA, we found only LAD > 40 mm and ERAF to be predictors of RAF. We identified OSA as a potential targetable risk factor in PeAF patients undergoing CBA. Out of risk scores tested for discriminating risk of RAF, BASEAF2 had the best performance.

Touch-up and recurrence rates after voltage mapping for verification of pulmonary vein isolation following cryoablation of paroxysmal atrial fibrillation

PURPOSE

The procedural endpoint following cryoballoon ablation (CA) for paroxysmal atrial fibrillation (PAF) is pulmonary vein isolation (PVI), which is typically confirmed by entrance/exit block using a circular mapping catheter. The present study added an assessment of ablation gaps with high-density voltage mapping after standard confirmation of PVI. Relationships between the need for touch-up ablation, patient characteristics, and atrial arrhythmia recurrence were explored.

METHODS

PAF patients received CA through standard of care treatment, with PVI assessed by bidirectional block confirmation, followed by voltage mapping. Radiofrequency ablation was performed as needed for voltage breakthrough and or additional rhythms. Freedom from atrial arrhythmia recurrence through 12-month follow-up was analyzed retrospectively with statistical survival models.

RESULTS

A total of 77 PAF patients (age 66.1 ± 11.6, CHADS₂ 1.8 ± 1.0) were followed for 1.2 ± 0.3 years after CA. During the index procedure, pulmonary vein (PV) touch-up was required in 59 patients (76.6%) and ablation of additional atrial fibrillation targets beyond PV was required in 26 patients (33.8%). Kaplan-Meier estimates of freedom from atrial arrhythmia recurrence at 1 year were 62 ± 6%. Rates were lower for patients requiring touch-up ablation (58 ± 6% vs. 78 ± 10%) or with CHADS₂ scores > 2 (33 ± 12% vs. 69 ± 6%). Cox regression models showed that the need for touch-up ablation increased recurrence (p = .045, HR = 2.6) after adjusting for hypertension and heart failure.

CONCLUSION

The high rate of PV touch-up suggests that initial CA lesions may be less durable than previously assumed, while the higher recurrence rate in patients requiring touch-up may indicate that additional factors make these patients more difficult to treat.