Perspectives

Endoscopic myotomy for achalasia


 

Heller myotomy is still the gold standard

BY ROBERT M. SIWIEC, MD

Achalasia is a rare, primary esophageal motor disorder characterized by ineffective relaxation of the lower esophageal sphincter (LES) and concomitant loss of esophageal peristalsis. High-resolution esophageal manometry has allowed for the diagnosis and classification of achalasia into relevant clinical subtypes which become important when discussing and considering treatment options. Confirmatory studies (e.g., timed barium esophagram) and provocative manometric maneuvers (e.g., upright swallows, rapid swallow sequence, and/or rapid drink challenge) can be helpful when distinguishing between true achalasia versus achalasia variants and esophagogastric junction outflow obstruction.

Dr. Robert Siwiec is a gastroenterologist at Indiana University Health Methodist Hospital

Dr. Robert Siwiec

Treatment options only provide palliation by eliminating outflow obstruction caused by a nonrelaxing and often times hypertensive LES. Pharmacotherapy (e.g., oral nitrates, 5-phosphodiesterase inhibitors, anticholinergics) is the least effective option because of medication side effects and short-acting duration. I only consider it for patients who are either unwilling or unable to tolerate invasive therapies. Botulinum toxin injection into the LES can be considered in patients who are not good candidates for more definitive therapy with PD or myotomy (endoscopic or surgical). Although the success rates with botulinum toxin are comparable with PD and surgical myotomy, patients treated with botulinum toxin require retreatment. Furthermore, continued botulinum toxin injections can compromise tissue planes making myotomy complex and challenging.

During the 1970s and 1980s, PD was the primary treatment modality for achalasia. Surgical myotomy was reserved for patients who suffered a perforation during PD or developed recurrent symptoms after multiple dilations. Minimally invasive surgery (left thoracoscopic approach) for achalasia was first introduced in the early 1990s and was shown to be a feasible, safe, and effective procedure, becoming the primary treatment approach in most centers. Patients fared well; however, it was soon discovered that >50% had pathological reflux based on pH monitoring. A few centers then began to perform a Heller myotomy through a laparoscopic approach with the addition of a fundoplication resulting in significant reductions in pathological reflux by pH monitoring. Eventually, a seminal RCT confirmed the importance of fundoplication with laparoscopic Heller myotomy (LHM) – resolution of dysphagia was unaffected and pathological reflux was avoided in most patients.1 Overall, clinical success rates for LHM with fundoplication are typically >90% and reflux incidence rates <10% with the overall complication rate being about 5% with reported mortality <0.1%.

PD remains appealing in that it is cost effective and less invasive, compared with POEM and LHM. Initial success rates and short-term efficacy are comparable with LHM but unfortunately PD’s efficacy significantly wanes over time. POEM, introduced by Inoue et al. in 2010, is a novel endoscopic technique with an excellent safety profile that provides good symptom relief while avoiding abdominal wall scars for patients. It has been shown to have a distinct advantage in patients with type III achalasia by nature of the longer myotomy not achievable by LHM.2 POEM has seen increasing enthusiasm and acceptance as a standard treatment option for achalasia largely because of the fact that its safety and efficacy have been shown to be comparable and in most cases equal with LHM. However, in 2020, direct comparison with LHM is challenging given that the follow-up in the majority of studies is either short or incomplete. The most recent multicenter, randomized trial comparing POEM with LHM plus Dor fundoplication showed POEM’s noninferiority in controlling symptoms of achalasia, but only after a 24 month follow-up.3 A recent report included one of the largest cohorts of post-POEM patients (500), but the 36-month data were based on the follow-up of only 61 patients (about 12%).4

Once the muscle fibers of the LES are disrupted, reflux will occur in the majority of patients. Unlike LHM, no concomitant fundoplication is performed during POEM and this increases the incidence of GERD and its long-term sequelae including peptic strictures, Barrett’s esophagus, and adenocarcinoma. A meta-analysis from 2018 looked at published series of POEM and LHM with fundoplication and found that GERD symptoms were present in 19% of POEM patients, compared with 8.8% of LHM patients. Worse yet, esophagitis was seen in 29.4% of the POEM group and 7.6% of the LHM group, with more individuals in the POEM group also having abnormal acid exposure based on ambulatory pH monitoring (39.0% vs. 16.8%).5

Proponents of POEM will argue that proton pump inhibitors (PPIs) are the panacea for post-POEM GERD. Unfortunately, this approach has its own problems. PPIs are very effective at reducing acid secretion by parietal cells, but do not block reflux through an iatrogenically incompetent LES. The drumbeat of publications on potential complications from chronic PPI use has greatly contributed to patients’ reluctance to commit to long-term PPI use. Lastly, the first case of early Barrett’s cancer was recently reported in a patient 4 years post-POEM despite adherence to an aggressive antisecretory regimen (b.i.d. PPI and H2 blocker at bedtime).6 LHM with fundoplication significantly reduces the risk of pathological GERD and spares patients from committing to lifelong PPI therapy and routine endoscopic surveillance (appropriate interval yet to be determined) and needing to consider additional procedures (i.e., endoscopic or surgical fundoplication).

Despite POEM’s well established efficacy and safety, the development of post-POEM GERD is a major concern that has yet to be adequately addressed. A significant number of post-POEM patients with pathological reflux have asymptomatic and unrecognized GERD and current management and monitoring strategies for post-POEM GERD are anemic and poorly established. Without question, there are individual patients who are clearly better served with POEM (type III achalasia and other spastic esophageal disorders). However, as we continue to learn more about post-POEM GERD and how to better prevent, manage, and monitor it, LHM with fundoplication for the time being remains the tried-and-tested treatment option for patients with non–type III achalasia.

References

1. Richards WO et al. Heller myotomy versus Heller myotomy with Dor fundoplication for achalasia: A prospective randomized double-blind clinical trial. Ann Surg. 2004;240:405-12.

2. Podboy AJ et al. Long-term outcomes of peroral endoscopic myotomy compared to laparoscopic Heller myotomy for achalasia: A single-center experience. Surg Endosc. 2020. doi: 10.1007/s00464-020-07450-6.

3. Werner YB et al. Endoscopic or surgical myotomy in patients with idiopathic achalasia. N Engl J Med. 2019;381(23):2219-29.

4. Inoue H et al. Peroral endoscopic myotomy: A series of 500 patients. J Am Coll Surg. 2015;221:256-64.

5. Repici A et al. GERD after peroral endoscopic myotomy as compared with Heller’s myotomy with fundoplication: A systematic review with meta-analysis. Gastrointest Endosc. 2018;87(4):934-43.

6. Ichkhanian Y et al. Case of early Barrett cancer following peroral endoscopic myotomy. Gut. 2019;68:2107-10.

Dr. Siwiec is assistant professor of clinical medicine, division of gastroenterology and hepatology, GI motility and neurogastroenterology unit, Indiana University, Indianapolis. He has no conflicts of interest.

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