Long-Term Outcomes of the Maze Procedure Combined With Mitral Valve Repair: Risk of Thromboembolism Without Anticoagulation Therapy

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.

Machine learning-based analysis of risk factors for atrial fibrillation recurrence after Cox-Maze IV procedure in patients with atrial fibrillation and chronic valvular disease: A retrospective cohort study with a control group

Objectives

To evaluate the efficacy of the Cox-Maze IV procedure (CMP-IV) in combination with valve surgery in patients with both atrial fibrillation (AF) and valvular disease and use machine learning algorithms to identify potential risk factors of AF recurrence.

Methods

A total of 1,026 patients with AF and valvular disease from two hospitals were included in the study. 555 patients received the CMP-IV procedure in addition to valve surgery and left atrial appendage ligation (CMP-IV group), while 471 patients only received valve surgery and left atrial appendage ligation (Non-CMP-IV group). Kaplan-Meier analysis was used to calculate the sinus rhythm maintenance rate. 58 variables were selected as variables for each group and 10 machine learning models were developed respectively. The performance of the models was evaluated using five-fold cross-validation and metrics including F1 score, accuracy, precision, and recall. The four best-performing models for each group were selected for further analysis, including feature importance evaluation and SHAP analysis.

Results

The 5-year sinus rhythm maintenance rate in the CMP-IV group was 82.13% (95% CI: 78.51%, 85.93%), while in the Non-CMP-IV group, it was 13.40% (95% CI: 10.44%, 17.20%). The eXtreme Gradient Boosting (XGBoost), LightGBM, Category Boosting (CatBoost) and Random Fores (RF) models performed the best in the CMP-IV group, with area under the curve (AUC) values of 0.768 (95% CI: 0.742, 0.786), 0.766 (95% CI: 0.744, 0.792), 0.762 (95% CI: 0.723, 0.801), and 0.732 (95% CI: 0.701, 0.763), respectively. In the Non-CMP-IV group, the LightGBM, XGBoost, CatBoost and RF models performed the best, with AUC values of 0.738 (95% CI: 0.699, 0.777), 0.732 (95% CI: 0.694, 0.770), 0.724 (95% CI: 0.668, 0.789), and 0.716 (95% CI: 0.656, 0.774), respectively. Analysis of feature importance and SHAP revealed that duration of AF, preoperative left ventricular ejection fraction, postoperative heart rhythm, preoperative neutrophil-lymphocyte ratio, preoperative left atrial diameter and heart rate were significant factors in AF recurrence.

Conclusion

CMP-IV is effective in treating AF and multiple machine learning models were successfully developed, and several risk factors were identified for AF recurrence, which may aid clinical decision-making and optimize the individual surgical management of AF.

The «labyrinth» operative procedure with the left atrium plasty in correction of isolated failure of a mitral valve

Objective. To study the possibilities of the «labyrinth» procedure in combination with the left atrium reduction. Materials and methods. Into the investigation 261 patients, suffering isolated failure of a mitral valve Stage IV, operated in the National Institute of Cardio-Vascular Surgery n. a. M. M. Amosov, were included. The left atrium plasty with objective to reduce and prevent the waves spread re-entry was performed in 139 (53.2%) patients. Fragmentation in the left atrium was made in regime of low radiofrequencies (25 - 35 Вт) in accordance to schemes of Maze ІІІ, ІV. Results. In the hospital period 5 patients died (the hospital lethality have constituted 1.9%). While discharge from the hospital the sinus rhythm was noted in majority of the patients after the left atrium plasty, than in the alternative group - in 119 (85.6%) of 139 and in 79 (64.8%) of 122 patients, accordingly. Conclusion. The «labyrinth» procedure in combination with the left atrium plasty owes significant clinical advantages, including restoration and persistence of the sinus rhythm in patients, suffering pathology of a mitral valve.

Human Tissue Analysis of Left Atrial Adipose Tissue and Atrial Fibrillation after Cox Maze Procedure

Cardiac adipose tissue is a well-known risk factor for the recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation, but its correlation with maze surgery remains unknown. The aim of this study was to investigate the correlation between the recurrence of AF and the adipose component of the left atrium (LA) in patients who underwent a modified Cox maze (CM) III procedure. We reviewed the pathology data of resected LA tissues from 115 patients, including the adipose tissue from CM-III procedures. The mean follow-up duration was 30.05 ± 23.96 months. The mean adipose tissue component in the AF recurrence group was 16.17% ± 14.32%, while in the non-recurrence group, it was 9.48% ± 10.79% (p = 0.021), and the cut-off value for the adipose component for AF recurrence was 10% (p = 0.010). The rates of freedom from AF recurrence at 1, 3, and 5 years were 84.8%, 68.8%, and 38.6%, respectively, in the high-adipose group (≥10%), and 96.3%, 89.7%, and 80.3%, respectively, in the low-adipose group (<10%; p = 0.002). A high adipose component (≥10%) in the LA is a significant risk factor for AF recurrence after CM-III procedures. Thus, it may be necessary to attempt to reduce the perioperative adipose portion of the cardiac tissue using a statin in a randomized study.

Cox maze IV versus left atrial reduction for atrial contraction restoration

Background

The Cox maze procedure is the gold-standard concomitant surgical procedure to restore sinus rhythm in rheumatic mitral valve disease with atrial fibrillation. Left atrial reduction surgery was found to be beneficial for rhythm conversion, but no study has investigated its efficacy compared to the Cox maze procedure for atrial contractility restoration. We aimed to compare the early success rate of left atrial contractility restoration with the Cox maze procedure and left atrial reduction in rheumatic subjects.

Methods

Preoperative and within one-month postoperative electrocardiograms and echocardiograms of patients who underwent a Cox maze IV procedure or left atrial reduction with mitral valve surgery were compared. Effective atrial contraction was defined as A wave peak velocity ≥10 cm·s−1 or atrial filling fraction ≥20%.

Results

Ninety patients (mean age 40.6 ± 10.2 years, 66.7% female) were divided equally into group A (Cox maze IV) and group B (left atrial reduction). The early sinus rhythm conversion rate was 64.4% versus 24.4% ( p < 0.001) in groups A and B, respectively. In patients with restored sinus rhythm, contractility was restored in 41.4% and 36.4% ( p = 1.000). Postoperative left atrial volume index ≤76 mL·m−2 was an independent variable associated with early atrial contractility restoration in both groups (prevalence rate 0.97, p = 0.007).

Conclusions

In rheumatic subjects, the early sinus rhythm conversion rate was significantly higher after Cox maze IV compared to left atrial reduction, but for restoring left atrial contractility, left atrial reduction was not inferior to Cox maze IV.

Long-Term Risk of Ischemic Stroke After the Cox-Maze III Procedure for Atrial Fibrillation

BACKGROUND

The long-term risk of stroke after surgical treatment of atrial fibrillation is not well known. We performed an observational cohort study with long follow-up after the "cut-and-sew" Cox-maze III procedure (CM-III), including left atrial appendage excision. The aim was to analyze the incidence of stroke/transient ischemic attack (TIA) and the association to preoperative CHA₂DS₂-VASc (age in years, sex, congestive heart failure history, hypertension history, stroke/TIA, thromboembolism history, vascular disease history, diabetes mellitus) score.

METHODS

Preoperative and perioperative data were collected in 526 CM-III patients operated in four centers 1994 to 2009, 412 men, mean age of 57.1 ± 8.3 years. The incidence of any stroke/TIA was identified through analyses of the Swedish National Patient and Cause-of-Death Registers and from review of individual patient records. The cumulative incidence of stroke/TIA and association with CHA₂DS₂-VASc score was estimated using methods accounting for the competing risk of death.

RESULTS

Mean follow-up was 10.1 years. There were 29 patients with any stroke/TIA, including 6 with intracerebral bleedings (2 fatal) and 4 with perioperative strokes (0.76%). The remaining 13 ischemic strokes and six TIAs occurred at a mean of 7.1 ± 4.0 years postoperatively, with an incidence of 0.36% per year (19 events per 5,231 patient-years). In all CHA₂DS₂-VASc groups, observed ischemic stroke/TIA rate was lower than predicted. A higher risk of ischemic stroke/TIA was seen in patients with CHA₂DS₂-VASc score 2 or greater compared with score 0 or 1 (hazards ratio 2.15, 95% confidence interval: 0.87 to 5.32) but no difference by sex or stand-alone versus concomitant operation. No patient had ischemic stroke as cause of death.

CONCLUSIONS

This multicenter study showed a low incidence of perioperative and long-term postoperative ischemic stroke/TIA after CM-III. Although general risk of ischemic stroke/TIA was reduced, patients with CHA₂DS₂-VASc score 2 or greater had a higher risk compared with score 0 or 1. Complete left atrial appendage excision may be an important reason for the low ischemic stroke rate.