Phenotypic identification and classification of functional defecatory disorders using high-resolution anorectal...

Area of Science:

• Gastroenterology
• Physiology

Background:

• Defecatory disorders are often linked to pelvic floor dyssynergia, but a spectrum of anorectal dysfunctions exists.
• The distinctness and overlap of these disorders are not fully understood, complicating diagnosis.
• Anorectal manometry is a diagnostic tool, but abnormal pressure gradients can occur in healthy individuals during simulated evacuation.

Purpose of the Study:

• To characterize phenotypic variation in patients with chronic constipation using high-resolution anorectal manometry.
• To identify distinct manometric profiles associated with defecatory dysfunction.

Main Methods:

• High-resolution anorectal manometry was used to evaluate anorectal pressures and rectal balloon expulsion time.
• Principal components analysis was applied to high-resolution anorectal manometry data to characterize patient phenotypes.
• The study included 62 healthy women and 295 women with chronic constipation.

Main Results:

• Three distinct phenotypes were identified: high anal pressure, low rectal pressure, and a hybrid type combining low rectal pressure with impaired anal relaxation.
• These phenotypes effectively discriminated between healthy individuals and patients with abnormal rectal balloon expulsion times.
• Patient symptoms were not reliable predictors of prolonged rectal balloon expulsion times.

Conclusions:

• Principal components analysis of rectoanal pressures successfully identified three phenotypes (high anal, low rectal, hybrid) capable of distinguishing between normal and abnormal rectal balloon expulsion times.
• These manometric phenotypes offer a potential framework for classifying patients with defecatory disorders.
• The identified phenotypes may enhance the understanding of the pathogenesis of various defecatory disorders.