Ablation Therapy for Barrett Esophagus
Allon Kahn, MD
Cadman L. Leggett, MD
Ablation therapy for Barrett esophagus (BE) consists of the application of thermal energy (radiofrequency ablation), a cryogen (cryoablation), or a photosensitizer (photodynamic therapy) to induce superficial tissue injury and necrosis. Radiofrequency ablation (RFA) and cryoablation are safe, effective, and durable modalities that are considered the current standard of care in ablation therapy. It is important that patients with BE treated with ablation therapy be enrolled in a comprehensive surveillance program.
INDICATIONS
Ablation therapy is often used in combination with endoscopic resection in patients with BE with high-grade dysplasia or intramucosal adenocarcinoma. Patients with BE and low-grade may be considered for ablation therapy when the diagnosis is confirmed by a pathologist with expertise in BE and in cases of multifocal and/or recurrent low-grade dysplasia.
CONTRAINDICATIONS
Absolute
1. Known esophageal perforation or deep mucosal disruption
2. Inability to place ventilation tubing for active ventilationa
3. Esophageal varices in the region of targeted ablation
Relative
1. Significantly large hiatal hernia with intrathoracic stomacha
2. Known distal stricture or obstruction that may interfere with ventilationa
3. Prior history of gastric bypass surgerya
4. Prior radiation therapy to the esophagus
5. Ulceration or mucosal break (including pretreatment biopsy)
6. Eosinophilic esophagitis
7. Prior history of Heller myotomy or peroral endoscopic myotomy
PREPARATION
1. The patient must be instructed to fast overnight prior to the procedure, in order to ensure clearance of gastric contents. This is important both to minimize risk for aspiration and to ensure adequate function of ventilation tubing with cryotherapy.
2. Informed consent must be obtained prior to beginning the procedure. Possible adverse events and complications should be explained to the patient in sufficient detail.
3. Deep sedation or general anesthesia is commonly employed due to the length of the procedure and associated pain.
4. Antiplatelet therapy and/or anticoagulation should be held prior to the procedure if clinically appropriate
RADIOFREQUENCY ABLATION
RFA is a bipolar thermal ablative modality that requires contact between an electrode array and the esophagus. Circumferential RFA is performed in patients with a BE segment >2 cm in length, while focal RFA is performed to treat shorter segments or as follow-up to circumferential ablation. Fig. 9.1 highlights the steps involved in RFA.
EQUIPMENT
1. Upper endoscope with working channel ≥2.8 mm, light source, and image processor
2. Patient monitoring equipment (e.g., blood pressure cuff, pulse oximeter, capnography) as dictated by the degree and manner of sedation/anesthesia
3. Personal protective equipment (e.g., gloves, face mask/shield, gown)
4. Barrx flex energy generator, connector and footswitch
a. Barrx RFA catheters: Fig. 9.2 summarizes the various catheters used for RFA
b. Barrx RFA cleaning cap
c. RFA endoscopic guidewire or Savary guidewire
d. Wet gauze
e. 1% N-acetylcysteine solution
 FIG. 9.1 A long-segment of Barrett esophagus (BE) is inspected under (A) high-definition white light endoscopy and narrow band imaging. B, The esophagus is irrigated with 1% N-acetylcysteine solution prior to (C) circumferential radiofrequency ablation (RFA) using the Barrx 360 express balloon catheter. On follow-up surveillance endoscopy, (D) residual islands of BE are identified. E, Focal RFA using the Barrx 90 catheter is performed over the BE islands and (F) circumferentially across the gastroesophageal junction. |
PROCEDURE
Prior to performing ablation therapy, the BE segment should be carefully examined under high-definition white-light endoscopy and narrow band imaging with attention to areas of mucosal irregularity that may require endoscopic resection. If endoscopic resection is performed, it is best to postpone ablation therapy in order to avoid a higher rate of complications including perforation, bleeding, and stenosis. Endoscopic landmarks including
the gastroesophageal junction and squamocolumnar junction should be located and measured in centimeters from the incisors. The maximal and circumferential extent of the BE segment should be recorded along with the location of any BE islands.
the gastroesophageal junction and squamocolumnar junction should be located and measured in centimeters from the incisors. The maximal and circumferential extent of the BE segment should be recorded along with the location of any BE islands.
 FIG. 9.2 Radiofrequency Ablation Catheters. (Used with permission from Medtronic © 2018.) |
Circumferential RFA With Barrx 360 Express RFA Balloon Catheter
1. Irrigate the esophagus with 1% N-acetylcysteine solution and suction contents.
2. Place guidewire through the endoscope’s instrument channel and into the gastric body; remove endoscope leaving guidewire in place.
3. Pass the Barrx 360 express RFA balloon catheter over the guidewire and into the esophagus.
4. Reintroduce the endoscope alongside the RFA catheter for direct visualization with the tip of the endoscope proximal to the balloon.
5. Align the proximal edge of the balloon electrode 1 cm above the top of the BE segment. Confirm generator displays default energy-density setting of 10 J/cm2.
6. Inflate the balloon using the gray pedal on footswitch. Once the balloon is fully inflated, hold down the suction button and press the blue pedal on footswitch to deliver ablation energy one time.
7. Move the endoscope along with the catheter distally 4 cm and align the proximal end of the electrodes with the distal end of previous ablation zone. Repeat this step until ablation overlaps with the gastroesophageal junction.
8. Deflate the balloon and disconnect the catheter. Rotate catheter clockwise to re-wrap the electrode array on the balloon. Withdraw the endoscope along with the catheter and wire.Related posts:
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