A comparison of rectoanal pressures during Valsalva maneuver and evacuation uncovers rectoanal discoordination in defecatory disorders

Background It is suggested that patients with defecation disorders (DD) strain excessively or do a Valsalva maneuver (VM) during evacuation, resulting in rectoanal discoordination, which hinders rectal evacuation. However, definitive data are lacking. Methods Rectoanal pressures during evacuation and a VM were measured with seated high‐resolution manometry (HRM) in 64 healthy and 136 constipated women with a normal (84 women, C‐normal) or prolonged (52 women, C‐abnormal) balloon expulsion time (BET). The number of abnormal rectoanal parameters during evacuation and the joint distribution of pressures during evacuation and a VM were used to discriminate between controls and C‐abnormal BET patients. Key Results The peak anal pressure (5 s) during a VM accounted for 0%, 26%, and 49% of the variance in anal pressure during evacuation in healthy women, C‐normal BET, and C‐abnormal BET. The association between anal pressure during a VM and evacuation was stronger in C‐abnormal BET than in healthy women and C‐normal BET ( p for interaction <0.001). Fifty‐eight of 64 controls and 33 of 52 C‐abnormal BET patients had no or one abnormal parameter during evacuation; hence, the probability of C‐abnormal BET was 33/91 (36%). In patients with no or one abnormal parameter during evacuation, a logistic model based on anal pressures during evacuation and a VM discriminated between controls and patients with C‐abnormal BET with a sensitivity and a specificity of 67% and 75%. Conclusions Assessment of rectoanal pressures during evacuation and a VM uncovers rectaoanal discoordination and facilitates the diagnosis of DD in selected patients.