title: Long-term efficacy of Botulinum toxin in classical achalasia: a prospective study.
abstract: OBJECTIVE
  We sought to examine the long-term efficacy of intrasphincteric Botulinum toxin A injection in a prospective cohort study of 30 patients with achalasia.
  
  
  METHODS
  Thirty patients with classical achalasia were treated with intrasphincteric Botulinum toxin A injection. Follow-up consisted of clinical assessment, symptom scoring, and postinjection manometry.
  
  
  RESULTS
  Symptomatic improvement for >3 months was seen in 23 of 30 patients (77%). Of the 23 initial responders, seven (30%) experienced a sustained symptomatic response after a single Botulinum toxin injection (mean follow-up, 21 months). The remaining 16 initial responders (70%) eventually relapsed (mean initial response, 11 months). Nine received a 2nd Botulinum toxin injection, and seven experienced an ongoing response (mean duration, 9 months); two patients eventually required a 3rd injection with good effect (mean duration, 22 months). The remaining seven patients who relapsed after Botulinum toxin opted for pneumatic dilation or surgical myotomy. Five of the seven patients who had no initial response received a 2nd injection but again did not respond. A residual lower esophageal sphincter pressure <18 mm Hg after the first Botulinum toxin injection predicted a good response to Botulinum therapy (single or multiple injections, p < 0.002, positive predictive value = 0.71, negative predictive value = 1.0). Neither initial nor sustained response to Botulinum toxin could be predicted based on gender, age, duration of illness, previous pneumatic dilation, or esophageal motility before treatment.
  
  
  CONCLUSIONS
  We found that 77% of patients with classical achalasia experienced a good symptomatic response after Botulinum toxin and 30% of initial responders achieve sustained symptomatic relief after a single treatment with Botulinum toxin. The initial responders who relapsed did well with subsequent Botulinum toxin A. Lack of an initial symptomatic response and residual lower esophageal sphincter pressure > or =18 mm Hg after Botulinum toxin are associated with a poor response.
authors.affiliation: Department of Surgery, McMaster University, Hamilton, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Kolbasnik
authors.forename: W E
authors.initials: WE
authors.lastname: Waterfall
authors.forename: B
authors.initials: B
authors.lastname: Fachnie
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: G
authors.initials: G
authors.lastname: Tougas
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects; D015331:Cohort Studies; D004931:Esophageal Achalasia / Q000188:drug therapy*; D004943:Esophagogastric Junction / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000009:adverse effects; D011446:Prospective Studies; D012008:Recurrence; D019233:Retreatment; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A