Sequential hybrid ablation versus surgical CryoMaze alone for treatment of atrial fibrillation (SurHyb Trial): a protocol of the multicentre randomized controlled trial.

BACKGROUND: Atrial fibrillation is common in patients with structural heart disease who are undergoing cardiac surgery. Surgical CryoMaze has been shown to be an effective treatment in several trials, but success rates have varied considerably, between 47-95%. The sequential hybrid approach, combining surgical CryoMaze followed by radiofrequency catheter ablation, can achieve high freedom from atrial arrhythmias. However, in patients with concomitant surgical atrial fibrillation treatment, data comparing the hybrid approach to CryoMaze alone are lacking. METHODS: The SurHyb study was designed as a prospective, open-label, multicentre randomized trial. Patients with non-paroxysmal atrial fibrillation who were scheduled for coronary artery bypass grafting or valve repair/replacement were randomized to either surgical CryoMaze alone or surgical CryoMaze followed by radiofrequency catheter ablation 3 months post-surgery. The primary outcome measure was arrhythmia-free survival without class I or III antiarrhythmic drugs, which has been evaluated using implantable cardiac monitors. CONCLUSIONS: This is the first randomized study that compares concomitant surgical CryoMaze alone with the staged hybrid surgical CryoMaze followed by catheter ablation, in patients with non-paroxysmal atrial fibrillation using rigorous rhythm monitoring. The results may contribute to the optimization of the treatment in patients undergoing concomitant CryoMaze for atrial fibrillation.

The systemic-immune-inflammation index predicts the recurrence of atrial fibrillation after cryomaze concomitant with mitral valve surgery.

BACKGROUND AND AIMS: Inflammation plays a key role in the initiation and progression of atrial fibrillation (AF). The systemic inflammation indexes are easily evaluated and predict AF development. However, it's role in prediction of recurrence of AF is unknown. We aim to explore the association between the systemic inflammation indexes and recurrence of AF in patients underwent cryoablation (CryoMaze) concomitant with mitral valve surgery. METHODS: We examined systemic inflammation indexes during perioperative period in 122 patients between 2015 and 2018. Systemic inflammation indexes were developed by systemic immune-inflammation index (SII), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and lymphocytes to monocytes ratio. Univariate and multivariate analyses were performed to examine the association of each markers with recurrence of AF. RESULTS: Of the 122 patients included in this study, 22 patients (18%) experienced AF recurrence after CryoMaze concomitant with mitral valve surgery. There is no significant difference between each systemic inflammation indexes before surgery and recurrence of AF. In univariate analysis, MLR after surgery 3 days, PLR, MPLR, NLR, SII after surgery 7 days were able to predict recurrence of AF. In multivariate analyses, SII ≥ 1696 independently predicted recurrence (OR, 3.719; 95% CI, 1.417-9.760). Interestingly, baseline SII showed no significant in prediction of recurrence. It was sharply elevated after surgery and dropped slowly. In patients of recurrence, SII after 7 days of surgery increased again. CONCLUSIONS: The raised SII again was associated with an increased risk of the postoperative recurrence of AF and independently predicted the late recurrence of AF after CryoMaze concomitant with mitral valve surgery.

U-Shaped Association Between Intraoperative Net Fluid Balance and Risk of Postoperative Recurrent Atrial Tachyarrhythmia Among Patients Undergoing the Cryo-Maze Procedure: An Observational Study.

OBJECTIVE: The ability of perioperative fluid management to prevent postoperative recurrence of atrial tachyarrhythmia remains controversial. The aim of the present study was to assess if intraoperative net fluid balance was associated with atrial tachyarrhythmia recurrence after the Cryo-Maze procedure. DESIGN: An observational cohort study. SETTING: A tertiary care hospital from April 2007 to May 2019. PARTICIPANTS: Four hundred forty-four patients undergoing the Cryo-Maze procedure in conjunction with other cardiac surgeries. INTERVENTIONS: The Cryo-Maze procedure in conjunction with other cardiac surgeries. MEASUREMENTS AND MAIN RESULTS: The main outcome was early atrial tachyarrhythmia recurrence, consisting of atrial fibrillation, atrial flutter, or atrial tachycardia, within the first three months after surgery. Complete follow-up was achieved in 443 patients (99.8%), of them 127 (28.6%) developed early atrial tachyarrhythmia recurrence. The median intraoperative net fluid balance was 1,627 mL (interquartile range, -215 to 3,557 mL). Multivariate logistic regression showed that intraoperative net fluid balance (p = 0.001), preoperative AF duration (adjusted odds ratio, 1.40; 95% CI, 1.17-1.68; p < 0.001) and left atrial volume index (aOR, 1.61; 95% CI, 1.06-2.45; p = 0.025) were independent predictors of early atrial tachyarrhythmia recurrence. The adjusted log odds were lowest (-1.52) when net fluid balance was 1,557 mL. CONCLUSIONS: There is a significant U-shaped association between intraoperative net fluid balance and early atrial tachyarrhythmia recurrence among patients undergoing the Cryo-Maze procedure.

Sequential Hybrid Surgical CryoMaze and Transvenous Catheter Ablation of Atrial Fibrillation.

BACKGROUND: The aim of the study was to evaluate whether the sequential hybrid approach combining surgical CryoMaze followed by the radiofrequency (RF) catheter ablation can improve freedom from atrial arrhythmias. METHODS: Thirty-five patients with persistent atrial fibrillation underwent a CryoMaze procedure in conjunction with cardiac surgery for structural heart disease. Three months after surgery, all patients underwent a 7-day electrocardiogram Holter followed by an electrophysiological study and mapping of the left and right atria. All pulmonary veins were reisolated and all ablation lines were completed, if necessary, using RF energy. Patients were followed-up at 3 months, 6 months, and 12 months after the catheter ablation. RESULTS: Before the mapping study and RF ablation, nine patients (26%) had ongoing atrial fibrillation or atrial tachycardia, 10 patients (28%) had paroxysmal atrial tachyarrhythmia, and 16 patients (46%) had sinus rhythm on the 7-day Holter monitoring. During the electrophysiological procedure, complete cryoablation lines around the left pulmonary veins were found in 29 patients (83%), around the right pulmonary veins in 25 patients (71%), between the superior veins in 20 patients (57%), between the inferior veins in 27 patients (77%), across the mitral isthmus in 12 patients (34%), and across the cavotricuspid isthmus in one patient (3%). Arrhythmia-free survival rate of antiarrhythmic drugs after reisolation of the veins and completion of the lines was 86% at 12 months. CONCLUSION: Ablation lines created using surgical CryoMaze are often incomplete. Sequential surgical CryoMaze procedures followed by catheter ablation significantly increase freedom from arrhythmia in patients with persistent atrial fibrillation.

Lesion durability found during mandated percutaneous catheter ablation after surgical cryo-ablation for treatment of non-paroxysmal atrial fibrillation.

OBJECTIVES: Current recommendations support surgical treatment of atrial fibrillation (AF) in patients indicated for cardiac surgery. These procedures are referred to as concomitant and may be carried out using radiofrequency energy or cryo-ablation. This study aimed to assess the electrophysiological findings in patients undergoing concomitant cryo-ablation. METHODS: Patients with non-paroxysmal AF undergoing coronary artery bypass grafting and/or valve repair/replacement were included in the trial if concomitant cryo-ablation was part of the treatment plan according to current guidelines. The patients reported in this study were assigned to undergo staged percutaneous radiofrequency catheter ablation (PRFCA), i.e., hybrid treatment, as a part of the SURHYB trial protocol. RESULTS: We analyzed 103 patients who underwent PRFCA 105 ± 35 days after surgery. Left and right pulmonary veins (PVs) were found isolated in 65 (63.1%) and 63 (61.2%) patients, respectively. The LA posterior wall isolation and mitral isthmus conduction block were found in 38 (36.9%) and 18 (20.0%) patients, respectively. Electrical reconnections (gaps) in the left PVs were more often localized superiorly than inferiorly (57.9% vs. 26.3%, P = 0.005) and anteriorly than posteriorly (65.8% vs. 31.6%, P = 0.003). Gaps in the right PVs were more equally distributed anteroposteriorly but dominated in superior segments (72.5% vs. 40.0%, P = 0.003). There was a higher number of gaps on the roof line compared to the inferior line (131 (67.2%) vs. 67 (42.2%), P < 0.001). Compared to epicardial cryo-ablation, endocardial was more effective in creating PVs and LA posterior wall isolation (P < 0.05). Cryo-ablation using nitrous oxide (N20) or argon (Ar) gas as cooling agents was similarly effective (P = NS). CONCLUSIONS: The effectiveness of surgical cryo-ablation in achieving transmural and durable lesions in the left atrium is surprisingly low. Gaps are located predominantly in the superior and anterior portions of the PVs and on the roof line. Endocardial cryo-ablation is more effective than epicardial ablation, irrespective of the cooling agent used.

Outcomes and residual gap analysis after the modified cryomaze procedure performed via right minithoracotomy versus sternotomy.

Objectives: Developments in both technique and technology have enabled surgeons to perform the maze procedure via right minithoracotomy (RMT) to treat atrial fibrillation (AF). This study aimed to clarify the outcomes of the modified cryomaze procedure via the RMT approach compared with the sternotomy approach. Methods: The study cohort comprised 803 consecutive patients who underwent a modified cryomaze procedure (130 via RMT and 673 via sternotomy) for paroxysmal AF and persistent AF from January 2001 to March 2022. The Gray test was applied to compare the incidence of recurrent atrial tachyarrhythmias. Additionally, residual electrical gaps were investigated in the patients who underwent additional catheter ablation for recurrent atrial tachyarrhythmias. Results: The respective 1-, 2-, and 3-year cumulative incidences of recurrent atrial tachyarrhythmias were 13.1%, 19.5%, and 23.1% in the RMT group, and 9.3%, 10.9%, and 12.8% in the sternotomy group (Gray test P = .036). All 31 patients with recurrent atrial tachyarrhythmias underwent additional catheter ablation, comprising 14 (10.8%) in the RMT group and 17 (2.5%) in the sternotomy group. There was a significant intergroup difference in the site of residual electrical gaps; the RMT group more frequently had residual gaps in the tricuspid annulus than the sternotomy group (6.2% vs 0.4%; P < .001). Conclusions: In the modified cryomaze procedure via the RMT approach, ablation failure is more likely to occur at the tricuspid annulus, where the surgical field of view is relatively poor compared with the sternotomy approach. Therefore, surgical ablation should be performed with caution when the RMT approach is used.

Incidence of and risk factors for pacemaker implantation after the modified Cryo-Maze procedure for atrial fibrillation.

OBJECTIVES: The Maze procedure is a well-established treatment for atrial fibrillation. However, it is sometimes associated with bradycardia requiring pacemaker implantation. We assessed the rates of in-hospital and late-onset pacemaker implantation after the modified Cryo-Maze procedure and explored the risk factors for pacemaker implantation. METHODS: This study enrolled a series of 751 patients who underwent the modified Cryo-Maze procedure at our institution between 2001 and 2020. Multivariable Fine-Gray regression was used to analyze the risk factors for late-onset pacemaker implantation. RESULTS: Twelve patients (1.6%) underwent in-hospital pacemaker implantation, and 55 patients (7.3%) underwent late-onset pacemaker implantation during a median follow-up of 4.5 years (interquartile range, 1.4-10.0). The most common primary indication for pacemaker implantation was sick sinus syndrome (56 patients [7.5%]), followed by complete atrioventricular block (11 patients [1.5%]). The cumulative incidence of late-onset pacemaker implantation with death as a competing risk was 2.8% at 1 year, 7.7% at 5 years, and 10.8% at 10 years. Risk factors for late-onset pacemaker implantation included a longer preoperative atrial fibrillation duration (hazard ratio, 1.14; P < .001) and an older age (hazard ratio, 1.05; P = .001). The mortality, cumulative incidence of cerebrovascular accidents, and rate of atrial fibrillation recurrence were not significantly different between patients with and without pacemaker implantation. CONCLUSIONS: Longer preoperative atrial fibrillation duration and older age are risk factors for late-onset pacemaker implantation after the modified Cryo-Maze procedure. However, the incidence of pacemaker implantation is not associated with increased morbidity or atrial fibrillation recurrence.

Novel risk score for predicting recurrence of atrial fibrillation after the Cryo-Maze procedure.

OBJECTIVES: This study aimed to develop a novel risk score model for quantitative prediction of the rate of atrial fibrillation (AF) recurrence after the Cryo-Maze procedure in patients with persistent AF. METHODS: We enrolled 450 consecutive patients who underwent the Cryo-Maze procedure for persistent AF concomitant with other cardiac procedures in our institute between 2001 and 2019. We randomly divided the cohort into two groups. We derived a model in a 'development cohort' (270 patients; 60%) and validated it in a 'test cohort' (180 patients; 40%) by receiver operating characteristic curve analysis. RESULTS: The median follow-up was 5.2 (interquartile range: 2.0-9.9) years. The 1-, 5-, 10- and 15-year rates of freedom from AF recurrence in the entire cohort were 91.4%, 83.5%, 76.2% and 57.1%, respectively. Risk factors for AF recurrence examined by logistic regression analysis included F-wave voltage in V1 < 0.2 mV, preoperative AF duration >5 years and left atrial volume index >100 ml/m2. Points were assigned to each risk factor according to its odds ratio. A novel risk score model was developed using these three variables and age, with a range up to 10 points. High score (>7) predicted high rates of AF recurrence after the Cryo-Maze procedure. The area under the receiver operating characteristic curve of the novel risk model score was 0.78 (95% confidence interval: 0.65-0.91) in the test cohort. CONCLUSIONS: Use of the Cryo-Maze procedure should be carefully considered in patients with a higher model score because of a higher risk of AF recurrence.

Comparison of CryoMaze With Cut-and-Sew Maze Concomitant With Mitral Valve Surgery: A Randomized Noninferiority Trial.

In this trial, we sought to evaluate the efficacy and safety of the addition of the Maze performed by cryoablation (CryoMaze) to the mitral valve surgeries. The trial is a randomized, single-center trial to determine whether CryoMaze was noninferior to cut-and-sew maze procedure (CSM) in patients with persistent or long-standing persistent atrial fibrillation (AF), with a 15% margin to establish noninferiority. The primary endpoint was freedom from AF off antiarrhythmic drugs (AADs) at 12 months. Secondary endpoints included freedom from AF off AADs at 3 and 6 months, and a composite of serious adverse events. Two hundred patients were randomized to either CryoMaze (n = 100) or CSM (n = 100). Freedom from AF was achieved in 85 % (95% confidence interval, 0.76-0.91) in the CryoMaze group and 88% (95% confidence interval, 0.80-0.94) in the CSM group, showing that CryoMaze was noninferior to CSM at 12 months (P value for noninferiority = 0.0065). There was no significant difference in serious adverse effects (n = 12 in CryoMaze; n = 17 in CSM; P = 0.315). Perioperative bleeding and the length of surgery, ICU stay, postoperative hospital stay; and the need for temporary pacing decreased significantly in the CryoMaze group. CryoMaze was noninferior to CSM for efficacy and safety for patients with persistent or long-standing persistent AF undergoing mitral valve surgeries. CryoMaze significantly decreased bleeding, the length of surgery, ICU and hospital stay, as well the need for temporary pacing. (Chinese Clinical Trial Register number, ChiCTR-IOR-16008112.).

Contemporary outcomes of the concomitant CryoMaze procedure.

OBJECTIVES: As an institutional strategy, the CryoMaze procedure has been established for treating atrial fibrillation (AF) since 2001. In this study, we aimed to analyse the contemporary outcomes of the CryoMaze procedure and to examine the predictive factors of successful sinus rhythm conversion. METHODS: Between January 2009 and March 2018, we performed 352 CryoMaze procedures. The contemporary outcomes of the CryoMaze procedure concomitant with other cardiac procedures were analysed by the Kaplan-Meier method. The logistic regression model was used to predict risk factors for recurrent AF. RESULTS: There were no 30-day or in-hospital deaths and all of the patients were discharged. The 1- and 5-year survival rates were 99.0% and 94.6%, respectively. The rates of freedom from permanent pacemaker implantation and cerebrovascular accidents were 92.6% at 1 year and 86.9% at 5 years, and 99.1% at 1 year and 97.9% at 5 years, respectively. The rates of freedom from recurrent permanent AF were 91.9% at 1 year and 86.1% at 5 years. The multivariable analysis showed that the independent predictive factors for recurrent permanent AF included an F-wave grade in lead V1 (P < 0.001), the preoperative duration of persistent AF (P = 0.031), a non-mitral procedure (P = 0.019) and a preoperative tricuspid regurgitation grade (P = 0.034). CONCLUSIONS: Preoperative voltage of the F wave in V1 lead is strongly associated with the sinus rhythm restoration after the CryoMaze procedure.

Atrio-oesophageal fistula after the cryomaze procedure.

We report a case of an atrio-oesophageal fistula after biatrial cryomaze ablation for atrial fibrillation, a complication that has not yet been described in the literature for the cryomaze method. Our report also serves as a reminder of this rare but lethal complication- that it can occur after any method of ablation for atrial fibrillation and a high index of suspicion for its diagnosis must be maintained to allow for early surgical treatment which offers the best chance of survival.

Sequential Hybrid CryoMaze Ablation versus Surgical CryoMaze Alone for the Treatment of Atrial Fibrillation (SurHyb): study protocol for a randomized controlled trial.

BACKGROUND: Atrial fibrillation is common in patients with structural heart disease who are undergoing cardiac surgery. Surgical CryoMaze has been shown to be an effective treatment in several trials, but success rates have varied considerably, between 47-95 %. The sequential hybrid approach, combining surgical CryoMaze followed by radiofrequency catheter ablation, can achieve high freedom from atrial arrhythmias, even when rigorous methods to detect arrhythmias after the procedure are used. However, data from randomized trials comparing hybrid ablations to surgical ablations alone are lacking. METHODS/DESIGN: The SurHyb study is a prospective, multicenter, randomized study. Patients with persistent or long-standing persistent atrial fibrillation will be randomized to either surgical CryoMaze alone or surgical CryoMaze followed by catheter ablation 3 months post-surgery. The primary outcome measure is arrhythmia-free survival without class I or III antiarrhythmic drugs, which will be evaluated using 7-day ECG Holter monitoring at 24 months. A total of 260 patients will be investigated from three medical centers in the Czech Republic to obtain the relevant information. DISCUSSION: This is the first randomized study that compares surgical CryoMaze alone with the staged hybrid surgical CryoMaze followed by catheter ablation in patients with persistent or long-standing persistent atrial fibrillation. These results will contribute to the optimization of the treatment for these patients. TRIAL REGISTRATION: Czech Clinical Trials Registry, cz-301020151253 . Registered on 30 October 2015.