Anesthesia for Maze Procedures

Overview

• AF affects millions globally and is associated with increased mortality and morbidity.⁴ It is particularly common in patients with other cardiovascular pathologies, especially those with valvular heart disease.³ In patients undergoing cardiac surgery, the prevalence of AF is as high as 50% in patients with mitral valve disease.⁴
• Surgical ablation consists of a predefined set of lesions in both atria.⁴ The specific pattern of atrial lesion of the Maze procedure was introduced in 1987 and has evolved into Maze III and Maze IV, using alternative energy sources (cryoablation and radiofrequency ablation) to create a permanent transmural lesion to eliminate AF.²
• Most strokes due to AF originate from blood clots that form in the trabeculated portions of the left atrial appendage (LAA).⁵ There are multiple ways to close the LAA during surgery, and it should be performed as part of the procedure.
• Surgical treatment of AF can be classified as concomitant, stand-alone, or hybrid surgical ablation procedures.
  • A concomitant surgical AF ablation is one performed during another cardiac surgery procedure, such as mitral valve surgery or coronary artery bypass grafting.
  • A stand-alone surgical procedure is performed solely for the arrhythmia, and can be done open, typically via a sternotomy, or minimally invasive, with or without cardiopulmonary bypass (CPB).
  • A hybrid procedure is a minimally invasive cardiac procedure followed by a catheter-based ablation or vice versa.⁶

Surgical and Anesthetic Considerations

Conditions commonly associated with AF that specifically affect anesthetic planning:

• Concomitant cardiac disease: valvular heart disease, coronary artery disease, pulmonary hypertension
• Endocrine disorders: hyperthyroidism, diabetes mellitus, electrolyte disturbances
• Chronic kidney disease, anemia
• Chronic lung disease, obstructive sleep apnea

Other special considerations include:

• A history of previous sternotomy or thoracotomy can interfere with surgical access and increase intraoperative bleeding.
• A history of cerebrovascular accidents and or transient ischemic attack requires a preoperative assessment of neurological deficits.
• Intraoperative transesophageal echocardiography is used to guide the procedure. A history of dysphagia, stricture or surgeries should be elicited.
• Management of anticoagulation in the perioperative period.
• Rate and rhythm control therapy includes individualized strategies to optimize patient outcomes.
• When surgical ablation is performed concurrently with another cardiac procedure via sternotomy, anesthetic management follows the same principles as those used in standard open-heart surgery.
• Stand-alone surgical ablation may be considered for patients with symptomatic persistent AF who have had unsuccessful catheter ablation or cannot achieve rhythm control with antiarrhythmic drug therapy and prefer a surgical approach.
• In the early 2000s, thoracoscopic maze procedures emerged as a minimally invasive alternative to standard sternotomy. These procedures employ video-assisted thoracoscopy to access the pericardium via the pleural space, perform ablation, and isolate the LAA.⁷
• Isolation of the posterior left atrium (LA) is a critical component of the Cox-Maze procedure for AF (Figure 1). The posterior LA, including the pulmonary veins, plays a central role in both the initiation and maintenance of AF. Electrophysiologic studies have consistently demonstrated that 87% to 96% of ectopic atrial foci in patients with AF originate within this region.⁸

Thoracoscopic AF (Stand-Alone)

General Considerations

• A thorough airway evaluation is warranted since a larger double-lumen endotracheal tube is required.
• Preoperative assessment should include the patient’s ability to tolerate one-lung ventilation.
• A careful review of previous transthoracic/transesophageal echocardiograms should be performed.

Intraoperative Management

• Patients are usually positioned supine with arms tucked to allow emergency conversion to sternotomy.
• External defibrillation pads are placed and connected before induction.
• CPB and a perfusionist should be available on standby in case of major complications.
• Lung isolation: Standard maneuvers must be used to manage hypoxia arising during one-lung ventilation.
• Advanced airway techniques or lung isolation strategies may be necessary in high-risk individuals to ensure optimal ventilation and to minimize perioperative complications.
• Pulmonary vein clamping may transiently cause hypoxia, hypotension, or decreased end-tidal CO₂, but these issues usually resolve after unclamping.

Monitoring and Intraoperative Anesthesia Plan

In addition to standard American Society of Anesthesiologists monitors:

• Arterial line for continuous blood pressure monitoring and arterial blood gases sampling
• Large-bore intravenous access or rapid infusion catheter; consider a central line
• Neuromuscular monitoring and depth of anesthesia monitoring
• Transesophageal echocardiography
• Cross-matched blood available

Intraoperative Transesophageal Echocardiography¹⁰

Complications, Outcomes, and Long-term Efficacy

Potential complications include:

• Major bleeding requiring thoracotomy or CPB conversion
• Pericardial effusion
• Pleural effusions or hemothorax
• Left circumflex artery injury with regional wall motion abnormalities
• Pulmonary vein stenosis
• Atrial-esophageal fistula
• Pacemaker requirement
• Stroke
• Phrenic nerve palsy