Surgical Treatment of Patients with Aortic Valve Disease in Association with Atrial Fibrillation

*Alexandr Zotov, Oleg Shelest, Emil Sakharov, Robert Khabazov and Alexandr Troitsky*

### **Abstract**

The frequency of atrial fibrillation development in patients with severe aortic valve stenosis ranges from 4 to 30%. This arrhythmia significantly worsens patients' long-term survival. Currently, it is considered that performing ablation of arrhythmogenic myocardial areas during valve surgery does not impact in-hospital mortality and does not lead to prolonged hospital stay. According to modern recommendations, this procedure should be performed in all patients diagnosed with atrial fibrillation if the pericardium is opened. There are numerous ablation protocols available. For patients with isolated aortic valve disease, there is no need to open the atria during ablation. For the majority of patients with persistent atrial fibrillation, isolating the posterior wall of the left atrium, including the pulmonary vein areas, is sufficient. This article proposes an original approach to the combined treatment of valve disease and arrhythmia using the Perceval-S sutureless valve and the Gemini-S clamp-ablator. This approach reduces the time of cardiopulmonary bypass, which can benefit high-risk surgical patients.

**Keywords:** aortic valve, atrial fibrillation, aortic stenosis, sutureless, radio frequency ablation, Gemini-S, bicuspid valve

### **1. Introduction**

Atrial fibrillation (AF) is a common arrhythmia, affecting around 1–2% of the general population. The prevalence increases with age, reaching approximately 5–15% in individuals over 80 years [1]. Aortic valve disease, including aortic stenosis and aortic regurgitation, has reported a prevalence of around 0.5–1% in developed countries, increasing with age [2].

Aortic stenosis narrows the aortic valve opening, limiting blood flow from the left ventricle to the aorta. It is primarily a disease of aging caused by calcific degeneration, and it is the most common valvular heart disease in developed countries. The prevalence of AS in the elderly population (≥75 years) is estimated to be between 2.8 and 4.6% [3]. On the other hand, aortic regurgitation, the leaking or backflow of blood through the aortic valve, can be caused by various conditions, including

aging, hypertension and endocarditis. The prevalence of moderate to severe AR in the general population is estimated to be around 0.5% [4].

The co-occurrence of AF and aortic valve disease is not uncommon because there are shared risk factors [5]. Research suggests that AF occurs in approximately 4–30% of patients with severe aortic stenosis, depending on the study population and diagnostic methods [6]. AF is also associated with poorer outcomes in patients with aortic valve disease, including increased mortality and morbidity [7]. AF in the context of AS is associated with a higher risk of stroke and systemic embolism, which significantly complicates the management of these patients [7]. The epidemiology of AF in patients with AR is less researched. However, given the shared risk factors, it is not uncommon to see these conditions together. AF in AR patients is also associated with worse outcomes, similar to AS patients [8].

However, specific epidemiological data for the combination of AF and aortic valve disease is limited and further research is needed to understand this patient population better.

Managing patients with AF and aortic valve disease is complex and requires a multidisciplinary approach. Therapeutic strategies often involve a combination of rate or rhythm control, anticoagulation and valve intervention [8].

In the 1980s, several scientists developed surgical methods for treating atrial fibrillation. Williams proposed a procedure for isolating the left atrium [9]. However, this method showed its effectiveness mainly in the "left atrial" form of atrial fibrillation, leaving other forms less responsive to the procedure [10]. Guiraudon introduced the "Corridor" procedure, which involved the surgeon isolating the impulse conduction path from the sinoatrial node to the atrioventricular [11]. Despite its promise, the procedure was limited in restoring an adequate ventricular response to the sinus node's operation, while the atrial myocardium continued to contract asynchronously [12]. Both procedures could not comprehensively address three main challenges of arrhythmia: asynchronous contractions of the atria and ventricles, an inadequate ventricular response to stimulation, and blood stagnation in the atria [13]. Consequently, patients remained in the high-risk group for thromboembolic complications.

In 1987, Cox, based on electrophysiological studies and animal experiments, identified "macro-reentry" waves and established their size and the duration of circulation in a specific place of the atria [14]. This discovery led to the development of the "Labyrinth" procedure, which created a single path for the impulse from the sinus node to the atrioventricular by cutting and sewing the atria, thereby interrupting the circulation of the "macro-reentry" wave while preserving the activation of atrial tissues by the sinus node [15]. The first operation on a human heart took place on September 25, 1987, ultimately allowing the patient to avoid arrhythmia and the intake of antiarrhythmic drugs for 20 years [16].

The maze procedure had its drawbacks due to a high risk of complications. One of the lines in the surgical schema was situated near the sinus node, disrupting fibers responsible for the stress-induced response [17]. Another line blocked the Bachmann's bundle, significantly impairing interatrial conduction [18]. The procedure was carried out exclusively under conditions of artificial circulation, accompanied by a corresponding amount of complications [19].

For these reasons, the procedure was modified and technically simplified over the following decade. At a median observation period of 5.4 years, sinus rhythm was maintained in 97% of patients' post-surgery [20]. However, the procedure remained technically challenging, not easily accessible for mastering, and still accompanied by high perioperative risk [21]. These factors laid the groundwork for exploring energy

#### *Surgical Treatment of Patients with Aortic Valve Disease in Association with Atrial Fibrillation DOI: http://dx.doi.org/10.5772/intechopen.112888*

sources that would allow the creation of ablation lines without cutting atrial tissue and for seeking ways to minimize surgical access [22]. In 1996, after accumulating experience from over 200 variously modified maze procedures, the authors performed the first operation on isolated AF, utilizing cryoablation technology to create patterns that disrupted the circulating "macro-reentry" waves [23]. The operation time was significantly reduced, and cryoenergy simplified the procedure [24]. Around the same time, experiments were conducted with other energy sources, such as radiofrequency and microwave [25]. These various energy sources used to achieve transmural lesions of the atrial myocardium following the original procedures pattern formed the basis for creating its fourth modification, the "Maze-IV" [26]. Radiofrequency energy gained the most widespread adoption [27].

Currently, according to guidelines from the European Association for Cardiothoracic Surgery (EACTS), cardiac procedures, including ablation, are divided into two categories: primary open atrial operations and primary closed atrial operations. Aortic valve replacement surgery and coronary artery bypass surgery are classified as the second type [28].

The optimal protocol for radiofrequency ablation (RFA) during aortic valve surgery is a subject of ongoing research debate. There are multiple approaches to consider, each with its benefits and drawbacks. The decision to perform an entire maze-IV operation or a non-maze procedure pulmonary vein isolation (PVI), Box-Lesion and variations (PVI) without atrial incision depends on patient-specific factors.

The maze-IV procedure is the most complex form of surgical ablation for AF. It involves creating a "maze" of lesions in the atria, effectively interrupting the abnormal electrical pathways. The reported success rates are high, with up to approximately 80% of patients free from AF 1 year post-operatively. However, the procedure is time-consuming, and it carries risks of complications such as bleeding and pacemaker dependency [29]. The limitation of this procedure is using two types of ablation devices to achieve the full line protocol of the original procedure [30]. Ablation requires the use of monopolar devices, which cannot always create a homogeneous lesion line. If the mitral line of the maze procedure is incomplete, these partial lines can result in peri-mitral atrial flutter. Performing a complete maze procedure is only possible by using cryosurgery [31]. On the other hand, a PVI procedure without atrial incision is a less invasive procedure that involves using the radiofrequency bipolar clamp to create lesions around the pulmonary veins, thereby isolating them electrically and preventing AF. The significant advantage of this procedure is its simplicity and shorter operative time, which translates into less surgical risk. However, the success rate is generally lower than the full maze procedure, particularly in patients with persistent AF [32]. Oral et al. demonstrated that complete PVI might not be sufficient in all AF patients, suggesting that non-PV foci can contribute to AF in these individuals [33]. Other studies have extended these findings and identified additional trigger sites within the left atrium, including the posterior wall, the left atrial appendage, and the coronary sinus [34]. For these reasons, all patients with persistent atrial fibrillation should undergo isolation of the posterior wall of the left atrium (BOX-Lesion), including the orifices of the pulmonary veins. Resection of the left atrial appendage makes it possible to form an additional line passing from the ridge zone to the collector of the left pulmonary veins [35].

The decision between the three procedures should consider the patient's individual characteristics, including the type and duration of AF, left atrium volume index (LAVI), the patient's overall health status, and the risk of surgical complications. For example, in younger, healthier patients or those with persistent AF, an entire maze-IV

operation may be more beneficial despite its invasiveness. On the other hand, for older patients, those with significant comorbidities or those with paroxysmal AF, a PVI procedure without atrial incision may be preferable due to its lower surgical risk.

The optimal protocol for RFA during aortic valve surgery with AF is a tailored approach that considers the patient's characteristics and balances the potential benefits of AF elimination against the procedure's risks. Maze-III and non-maze procedures (PVI, Box-Lesion) without atrial incision have their place in the treatment of AF, and the choice between them should be made on a case-by-case basis.
