TT hybrid procedures ( Fig. 35.1 ) attempt to replicate as many of the left atrial lesions of the on-pump surgical Cox-Maze-III or-IV procedures as possible. However, off-pump TT surgical lesions in hybrid procedures are inherently limited to epicardial lesions only. The left atrial lesions that we perform epicardially are bilateral pulmonary vein isolation (PVI), left atrial posterior wall isolation, lesions across the Coumadin ridge from the left superior pulmonary vein (PV) to the left atrial appendage (LAA), selected ganglionic plexus ablation, and LAA occlusion. Additional endocardial lesions are performed either jointly or after a delay to create more of the Cox-Maze-III or-IV lesions and to “touch up” any incomplete epicardial lesions. Thus the TT approach depends on a partnership between surgeons and electrophysiologists who perform endocardial lesions including the mitral isthmus line, the coronary sinus lesion, and the right atrial cavotricuspid isthmus (CTI) lesion, none of which can be performed epicardially. TT hybrid procedures are less invasive than the Cox-Maze-III and-IV procedures, but they also have fewer final ablative lesions and therefore an expected higher failure rate than the more invasive on-pump surgical procedures.

Combined epicardial and endocardial catheter lesions in a totally thoracoscopic (TT) hybrid procedure. Blue lines, thoracoscopic epicardial ablation; rust lines, endocardial catheter ablation; green areas, ganglionic plexus ablation. An AtriClip is shown in place occluding the left atrial appendage.

Patients referred for a hybrid procedure have usually failed medical therapy and multiple catheter ablations. However, the success of a hybrid procedure depends primarily on whether the patient has paroxysmal AF (PAF) or nonparoxysmal AF (non-PAF; persistent AF or long-standing persistent AF [LSpAF]), on the size of the left atrium (LA), and on the duration of the AF. ^, Surgeons should explain the possibility of needing a new pacemaker, especially if the procedure is successful in ablating the AF. If the clinical history cannot identify the patient’s AF type, continuous ambulatory monitoring (e.g., Holter, iRhythm ZioPatch, Philips BioTel) for at least 7 days should be performed. Continuous ambulatory monitoring also detects the presence or absence of sick sinus syndrome, which is a major reason for needing a new postoperative pacemaker (see Chapter 21 ). left atrial size is determined by transesophageal echocardiography or contrast-enhanced cardiac computed tomography. A left atrial size greater than 5.5 cm is a known risk factor for decreased procedural success as is an AF duration of more than 5 years.

The clinical presentation of stand-alone AF may vary considerably. Paradoxically, those patients with longer-duration AF may express a lack of symptoms because of their gradual insidious deterioration, but more recently diagnosed patients can present with the typical findings of palpitations, dyspnea on exertion, chest pain, anxiety, and lightheadedness. Seemingly asymptomatic patients should also be made aware that AF is associated with heart failure, cognitive decline, and dementia, especially in the younger patient (younger than 70 years old) population. ^.

The 2017 HRS/European Heart Rhythm Association/European Cardiac Arrhythmia Society/Asia Pacific Heart Rhythm Society/Latin American Society of Cardiac Stimulation and Electrophysiology guidelines recommended isolated catheter ablation of PAF (Class I, Level A), persistent AF (Class IIa, Level B-NR), and LSpAF (Class IIb, C-LD). The most recent National Cardiovascular Data Registry AF Ablation Registry analysis (2016–2020) reflects the real-world implementation of these guidelines, demonstrating that catheter ablations were performed for 76,219 patients and were divided between PAF (55.8%), persistent (41.6%) and LSpAF (2.3%). These recommendations are based on the high success rate of PVI with catheter ablation and excellent safety profile. Metaanalysis of randomized controlled trials (RCTs) evaluating radiofrequency (RF) catheter ablation versus medical management of PAF reveal 65% to 71% freedom from recurrent AF at 1 year, and the recent STOP-AF trial revealed nearly 75% freedom from AF recurrence at 1 year when comparing balloon cryotherapy versus a rhythm control medical management approach in a PAF population. Therefore, surgeons who are referred patients with stand-alone PAF should first refer these patients to an electrophysiology colleague for evaluation of an isolated endocardial catheter ablation before considering a TT hybrid approach.

Patients with stand-alone persistent AF, however, pose a challenge to an isolated catheter ablation approach (see Chapter 31 ). As mentioned, patients with persistent AF develop atrial substrate abnormalities beyond the PVs and necessitate an ablation strategy targeted at reentrant circuits (drivers) that sustain AF. Linear ablation lesions based on the Cox-Maze-III or-IV lesion sets are required to interrupt these macro-reentrant drivers of AF. The crux of any ablation procedure, including catheter ablation, is lesion transmurality and continuity of the linear ablations without an increase in complications such as atrial perforation and atrial-esophageal fistulas. Several studies have now shown that epicardial-endocardial gaps exist in nearly one-third of patients undergoing catheter ablation, and often an adipose layer is present between these layers, which can act as a barrier to effective transmural ablation. This nontransmurality problem is not an issue with open surgical ablation using the cut-and-sew technique, cryosurgery, or bipolar RF clamps, but it is a major problem when using unipolar RF ablative approaches such as endocardial catheter ablation or off-pump epicardial surgical approaches. However, a bidirectional hybrid ablation approach can overcome the technical difficulty of creating transmural lesions. Several trials have now demonstrated that isolated catheter ablation that includes additional lesions beyond the PVI do not yield significantly improved freedom from AF when compared with isolated PVI alone. ^, The reason the additional lesions had no impact on the catheter ablation outcomes is because of the extreme difficulty in creating contiguous transmural linear lesions anywhere in the atrium with the tip of a long, moving catheter. It is also problematic for the surgeon to create the floor and roof lesions of the box lesion around all four PVs with a unipolar RF device whether it is a single or dual electrode device. The recent CAPLA study reported a disappointing 52.4% freedom from AF with a first-time catheter ablation of PVI and posterior wall isolation, which was not significantly improved over PVI alone (53.6%). Thus in patients with persistent AF and LSpAF, a TT hybrid procedure should be considered.

Patients with LSpAF are so difficult to treat with catheter ablation that patients with this type of AF often go untreated, but this is where hybrid procedures offer their greatest potential value. The CONVERGE trial was the first RCT to evaluate the efficacy and safety of a hybrid procedure to treat patients with these complex forms of non-PAF and it is discussed extensively in Chapter 36 . The recent gHARTCAP-AF trial was also an RCT that compared a hybrid procedure versus catheter ablation in patients with LSpAF. Patients undergoing the hybrid approach showed superior 12-month rhythm success compared with those undergoing catheter ablation (89% vs 41%, respectively; relative risk [RR], 1.78; P =.002). The more recent CEASE-AF RCT in patients with LSpAF (19.5%) again showed the superiority of hybrid procedures over catheter ablation at 12 months (71.6% vs 39.2%, respectively; RR, 1.83; P <.001).

On the basis of these RCTs and other prior nonrandomized comparisons, we believe that the indications for performing a hybrid procedure include (1) recurrent PAF despite multiple prior catheter ablations; (2) persistent AF with an enlarged or heavily scarred LA, left atrial fibrosis, or multiple prior failed catheter ablations; and (3) the presence of LSpAF.

Only patients with stand-alone AF are considered to be candidates for a hybrid procedure. Patients with significant concomitant cardiac disease requiring coronary artery bypass grafting (CABG) or valve surgery should not be offered a hybrid procedure, and their AF should be addressed according to the STS guidelines. Contraindications to a hybrid procedure include anatomic and physiologic considerations to both the off-pump epicardial surgical component and the ability to complete a subsequent endocardial catheter ablation. Strict contraindications to any combined hybrid approach include (1) the presence of left atrial thrombus, (2) an inability to tolerate anticoagulation, and (3) severe esophageal disease that would prohibit safe TEE. Other secondary contraindications include (1) prior atrial septal defect closure device., (2) an incomplete inferior vena cava (IVC), (3) prior cardiac surgery or mediastinal radiation, (4) previous pericarditis, (5) advanced liver disease, and (6) advanced pulmonary disease requiring home oxygen therapy. Increased body mass index (>45 kg/m ² ), depressed left ventricular ejection fraction (LVEF) (<25%), chronic kidney disease (stage >3), and a history of prior thoracic surgery can increase the technical difficulty of the epicardial surgical component but can be overcome safely with increasing surgeons experience.

Preoperative patient evaluation for a TT hybrid procedure includes (1) carotid duplex ultrasonography to evaluate for flow-limiting carotid stenosis leading to an increased risk of periprocedural stroke; (2) echocardiography and left heart catheterization to evaluate for concomitant structural heart disease warranting open cardiac surgery; (3) noncontrast computed topography to evaluate for left atrial, PV(s), and LAA anatomy; (4) pulmonary function tests to ascertain suitability for single lung ventilation; and (5) standard blood work to assess for other potential contraindications like end-stage liver disease or significant thrombocytopenia.

The non-Maze TT hybrid procedure is performed under general anesthesia, and double-lumen endotracheal intubation is performed in the operating room. The patient is positioned supine with inflatable bags aligned under each scapula to allow for differential inflation of each hemithorax during the procedure. Monitoring lines should include central venous access, an arterial line for blood pressure monitoring, and a Foley catheter. Transesophageal echocardiography is required to rule out the presence of LAA thrombus. Esophageal temperature monitoring is not routinely performed in our TT hybrid procedure. Defibrillator pads should be positioned to allow for appropriate port access and permit emergent conversion to sternotomy if needed. We prefer the use of sterile defibrillator pads. Intravenous (IV) unfractionated heparin is not routinely administered during a TT hybrid procedure. The patient is prepped with insufflation of both inflatable bags to maximize posterior-lateral exposure and optimize the area of skin prep from the neck to the posterior axillary lines and inferiorly to the groins bilaterally.

There are several iterations of TT hybrid procedures, and we will describe our institutional preference. We begin with a left-chest approach. Single right lung ventilation is initiated, and the left hemithorax is elevated with an inflatable Roho or 500-cc IV solution bag to aid with positioning of the left mediastinum. The patient is rotated a few degrees to the right to shift the mediastinal structures slightly rightward. The first port is 5 mm and inserted into the fourth intercostal space at the anterior axillary line to will act as the main camera port. The port should be inserted perpendicular to the chest wall and aimed at the pulmonary hilum. The ideal port placement is just anterior to the pulmonary hilum and in line with the PV carina. A 30-degree 5-mm camera is inserted to confirm appropriate placement. Carbon dioxide insufflation is initiated at 8 cm H ₂ O with a flow rate greater than 15 L/min. Deflation of the left lung results in excellent visualization of the left pulmonary hilum, pericardium, left phrenic nerve, and left hemidiaphragm.

A second 12-mm port is then placed at the second intercostal space at the lateral third of the clavicle and aimed toward the pulmonary hilum. This port is for insertion of the primary surgeon’s right-hand instrument. A third 12-mm port is placed at the sixth intercostal space at the midaxillary line and again directed at the pulmonary hilum. This port is for insertion of the primary surgeon’s left-hand instrument. A fourth and final 5-mm port is placed through the eighth intercostal space at the posterior axillary line to will serve as the assistant surgeon’s left-hand instrument. The overall configuration of the four-port placement should mimic a “hockey stick” with orientation around the pulmonary hilum and just posterior to the phrenic nerve ( Fig. 35.2 ). The typical instrument placement includes:

• •

  Port 1: a 5-mm 30-degree camera

• •

  Port 2: an Endo Kittner, a 32-cm laparoscopic monopolar hook Bovie cautery (set at 30-W coagulation), an Epicardial AtriCure MLP1 ablation device, and a 48-inch Endo Stitch (Medtronic)

• •

  Port 3: a suction irrigator and an Epicardial AtriCure MLP1 ablation device

• •

  Port 4: an Endo Kittner

Left chest port placement for thoracoscopic non-Maze hybrid ablation. Port placement: (1) 5-mm port at the fourth intercostal space along the anterior axillary line, (2) 12-mm port at the second intercostal space at the midclavicular line, (3) 12-mm port at the sixth intercostal space along the midaxillary line, and (4) 5-mm port at the eighth intercostal space along the midaxillary line.

Stay updated, free articles. Join our Telegram channel

Join