508 Relationship of Patient Factors to High Resolution Anorectal Manometry Findings in Chronic Constipation

INTRODUCTION: High resolution anorectal manometry (HRARM) is used to evaluate patients with chronic constipation by assessing anorectal sensory and motor dysfunction. Despite the growth of HRARM, there is still little known about the patient factors that are associated with manometric diagnoses of dyssynergic defecation (DD) and its subtypes Type I – IV. The aims of this study are: 1) to characterize the abnormalities on HRARM in patients with chronic constipation seen at our center; and 2) to correlate patient factors (demographics and symptoms) to abnormalities identified on HRARM. METHODS: HRARM of consecutive patients being evaluated for chronic constipation between July 2018 and February 2019 were included. Patients completed a questionnaire describing symptoms related to their bowel movements. HRARM was performed using ManoScan TM and analyzed using ManoView TM software (Medtronic, Shoreview, MN). Results are expressed as mean±SD or percentages. Metrics were compared using ANOVA or chi square tests, as appropriate. RESULTS: Of 170 patients included in the study, 63 had Type 1 DD, 24 had Type 2 DD, 16 had Type 3 DD, 17 had Type 4 DD, and 50 patients had a non-dyssynergic defecation pattern (Figure 1). Demographics: Patients with Type 3 DD were younger ( P = 0.02) and had a higher BMI ( P = 0.07), while patients with Type 1 DD were older ( P = 0.02) (Table 1). Additionally, patients with Type 1 or Type 2 DD were more likely to be men ( P = 0.02); a majority (29 of 36, 81%) of men had either Type 1 or Type 2 DD. Symptoms: Patients with Type 1 DD less frequently had 2 or less bowel movements per week ( P = 0.02). Several other symptoms trended towards a difference such as improvement of abdominal discomfort with bowel movement ( P = 0.15) and blockage sensation ( P = 0.13). Manometric profile: Patients with Type 2 and Type 4 DD had lower intrarectal pressure compared to Type 1 DD, Type 3 DD, and non-DD patients ( P < 0.001). CONCLUSION: Type 1 dyssynergic defecation is the most common form of anorectal dysfunction seen in patients with chronic constipation. Age and sex distribution differed between the dyssynergic defecation subtypes and normal HRARM populations. However, the symptom profile between these groups is largely the same. Thus, HRARM remains an important tool in differentiating dyssynergic defecation from other causes of chronic constipation.