Mid‐term outcomes of concomitant Cox‐Maze IV: Results from a multicenter prospective registry

Establishment and evaluation of a nomogram prediction model for risk of atrial fibrillation recurrence after the cox-maze IV procedure

The Cox-Maze IV (CMIV) procedure is the mainstay in surgical treatment of atrial fibrillation (AF), but the rate of AF recurrence after the CMIV procedure in patients with persistent AF is difficult to accurately evaluate. In this study, we aimed to develop and validate a risk prediction model of AF recurrence within 1 year after undergoing the Cox-Maze IV procedure. We retrospectively enrolled 303 consecutive patients who underwent the Cox-Maze IV procedure for persistent AF concomitant with other cardiac procedures at our institute between 2019 and 2021. A nomogram was developed using multivariate logistic regression analysis, and the concordance statistic (C-statistic) was computed. Differentiation, calibration, clinical suitability, and bootstrapping were performed to verify the model. Among the 303 patients, 71 developed recurrent AF within 1 year of CMIV. Factors predictive of postoperative AF recurrence included age, left ventricular hypertrophy (LVH), early atrial tachyarrhythmias (ATAs), and congenital heart disease surgery (namely, ventricular septal defect repair and atrial septal defect repair). Based on the training dataset, the nomogram had a C-statistic of 0.864 (95% CI 0.811-0.918) for predicting AF recurrence. According to the receiver operating characteristic curve, (ROC curve), the cutoff value of the model was 0.293, and the specificity and sensitivity were 0.841 and 0.789, respectively. This model can predict the risk of AF recurrence after the CMIV procedure. Its discrimination, calibration, and clinical applicability are strong, and its clinical application is simple and easy to promote.

Radiofrequency and Cryoablation as Energy Sources in the Cox-Maze Procedure: A Meta-Analysis of Rhythm Outcomes

AIM

Cox-maze IV is the most effective surgical procedure for atrial fibrillation (AF) treatment to date; however, few studies have compared the outcomes of the different energy sources applied to achieve transmurality. This study aimed to analyse the impact of the different energy sources on Cox-maze IV results in terms of sinus rhythm restoration.

METHOD

A systematic review and meta-analysis was conducted by including studies reporting rhythm outcomes on biatrial Cox-maze AF ablation with bipolar radio-frequency (BRF), cryoenergy (Cryo), or both (BRF+Cryo). The primary endpoints were the early and late rhythm outcomes of AF ablation using the different energy sources. Late AF recurrences were evaluated through timepoint analysis, and freedom from AF from Kaplan-derived data. Sixty articles including 8,293 patients were selected (3,364 patients Cryo, 1,937 BRF, and 2,992 BRF+Cryo).

RESULTS

At 6 months, AF incidence was significantly lower in the Cryo group at 6.73%; it was 25.52% in the BRF and 16.79% in the BRF+Cryo groups (p=0.0112). At the 4-year timepoint, AF incidence was lower in the Cryo group compared with the BRF and BRF+Cryo: 6.14% vs 51.59% vs 16.09%, respectively (p=0.0392). Freedom from AF was 76.7%±2.2%, 60.9%±2.2%, and 66.3%±1.6% for Cryo, BRF, and BRF+Cryo at 4 years, respectively (p<0.001). At meta-regression, mean left atrial diameter was positively associated with higher AF recurrences (OR 1.04, 95% CI 1.01-1.08; p=0.0159).

CONCLUSION

When performing this procedure, cryoablation seems to be associated with improved rhythm outcomes when compared with bipolar radiofrequency ablation.

Risk of neurologic events after surgery for mitral valve insufficiency and concomitant Cox-maze IV procedure for atrial fibrillation. A nationwide register-based study

OBJECTIVES

Analysis of the long-term risks of ischaemic stroke and cerebral bleeding in patients with atrial fibrillation after mitral valve surgery and concomitant Cox-maze IV procedure.

METHODS

In total, 397 patients with symptomatic degenerative mitral valve insuffciency and atrial fibrillation, underwent mitral valve surgery and Cox-maze IV in Sweden between 2009 and 2017. In this retrospective nationwide analysis, patients were followed in national patient registers until 30 September 2022.

RESULTS

There were 4 deaths within 30 days (1.0%). Mean follow-up was 8.7 (0.1-13.4) years. Survival without ischaemic stroke or cerebral haemorrhage at 5 and 10 years were 90% and 74%, respectively. Nineteen patients experienced an ischaemic stroke, of which 4 were fatal. Five of 34 patients (14.7%) with a history of stroke preoperatively experienced ischaemic stroke during follow-up. The linearized rate of ischaemic stroke per patient-year was 0.6% and was similar regardless of left atrial appendage closure during surgery or whether a mechanical valve was inserted. The observed ischaemic stroke rate was lower than the predicted rate for all CHA2DS2-VASc score groups. Fourteen patients suffered cerebral bleeding, of which 3 were fatal. Patients who experienced cerebral bleeding were older and had higher mechanical valve implantation rate than those without cerebral bleeding.

CONCLUSIONS

Surgery for mitral valve insufficiency and concomitant Cox-maze IV can be performed with low perioperative risk. There is a low continuing risk of stroke long-term postoperatively that correlates with a higher CHA2DS2-VASc score. Patients with preoperative stroke are at increased risk of postoperative stroke despite atrial fibrillation surgery.

Treating Atrial Fibrillation is No Maze: A Reminder to Heart Teams for Concomitant Surgical Ablation for Atrial Fibrillation With Cardiac Surgery

Atrial fibrillation (AF) is the most prevalent arrhythmia and is often found during times of other cardiac pathologies that require surgical management including coronary revascularization and valve surgery. Surgical ablation of AF, most frequently performed through the Cox-Maze IV procedure, is highly effective in restoring sinus rhythm. Despite robust society guideline recommendations for concomitant surgical ablation (CSA) for AF, the practice has yet to be widely adopted. In this review, we discuss the current indications for CSA, its efficacy in maintaining freedom from atrial tachyarrhythmias, stroke, and adverse long-term outcomes, the safety profile of SA when performed alongside cardiac surgical cases, and challenges with its implementation across the most common concomitant cardiac operations. In conclusion, we present a reminder to multidisciplinary heart teams to consider CSA when indicated for their patients.

Surgical options for atrial fibrillation treatment during concomitant cardiac procedures

Current guidelines recommend concomitant surgical ablation (SA) of atrial fibrillation (AF) in the context of mitral valve disease. A variety of energy sources have been tested for SA to perform effective transmural lesions reliably. To date, only radiofrequency and cryothermy energies are considered viable options. The gold standard for SA is the Cox-Maze ablation set, especially for non-paroxysmal AF (nPAF), with the aim of interrupting macro-reentrant drivers perpetuating AF, without hampering the sinus node activation of both atria, and to maintain the atrioventricular synchrony. Although the efficacy of SA in terms of early and late sinus rhythm restoration has been clearly demonstrated over the years, concomitant AF ablation is still underperformed in patients with AF undergoing cardiac surgery. From a surgical standpoint, concerns have been raised about whether a single (left) or double atriotomy would be justified in AF patients undergoing a "non-atriotomy" surgical procedure, such as aortic valve or revascularization surgery. Thus, an array of simplified lesion sets have been described in the last decade, which have unavoidably hampered procedural efficacy, somewhat jeopardizing the standardization process of ablation surgery. As a matter of fact, the term "Maze" has improperly become a generic term for SA. Surgical interventions that do not align with the principles of forming conduction-blocking lesions according to the Maze pattern, cannot be classified as Maze procedures. In this complex scenario, a tailored approach according to the different AF patterns has been proposed: for patients with concomitant nPAF, a biatrial Cox-Maze ablation is recommended. Conversely, it might be reasonable to limit lesions to the left atrium or the pulmonary veins in patients with paroxysmal AF (PAF) in some clinical scenarios. The aim of this review is to provide an overview of the current ablation strategies for patients with AF undergoing concomitant cardiac surgery.

Concomitant Surgical Ablation for Treatment of Atrial Fibrillation in Patients Undergoing Minimally Invasive Mitral Valve Surgery: A Single-Center Experience in Vietnam

BACKGROUND

 This study presents the early and midterm outcomes of combining atrial fibrillation (AF) treatment with minimally invasive mitral valve surgery (MIMVS) at our center.

METHODS

 From January 2017 to June 2022, our center treated a total of 86 patients with both MIMVS and surgical AF ablation. The patient cohort included 62 women (72.1%) and 24 men (27.9%). The average EuroScore II was 2.64 ± 1.49%, and the patients were followed up for an average period of 46.31 ± 9.84 months.

RESULTS

 Postoperatively, 95.3% of patients experienced a change in sinus rhythm, and 86.2% were discharged in sinus rhythm. The hospital's mortality rate was 2.3%, with a late mortality rate of 3.5%. Survival analysis revealed an atrial fibrillation-free 5-year follow-up rate of 59.1 ± 9.1%. The 5-year survival rate was 92.7 ± 3.3%.

CONCLUSION

 Our 5-year experience demonstrates that the combination of MIMVS and surgical AF ablation can be routinely performed with favorable peri- and postoperative outcomes. This reflects our hospital's culture and guidance on patient selection, particularly when adopting minimally invasive approaches for multiple procedures.