Impaired bladder perfusion in interstitial cystitis: a study of blood supply using laser Doppler flowmetry

Laser doppler flowmetry was used to study bladder blood flow in 16 patients with interstitial cystitis and in 18 control subjects. All studies were performed at cystoscopy under general anesthesia. Interstitial cystitis patients conformed to the diagnostic criteria of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Blood flow measurements were made at four specific sites in the bladder at a capacity of 100 ml. and at full capacity. The mean maximum capacity under anesthesia was 828 cc for the control group and 562 cc for the IC group. Blood flow at low capacity was similar in the two groups. When the bladder was filled to capacity, blood flow increased by a mean of 9.05 LDF units in the control group but only by 0.06 LDF units in the IC group (p = 0.007). Vault perfusion increased considerably more in the control group compared to the IC group (p = 0.002). The mean ratio of vault to trigonal perfusion was similar in both groups and was not affected by the overall blood flow changes which accompanied distension. Although the mean bladder capacity under anesthesia was greater in the control group, covariant analysis showed that the significant differences in perfusion between the two groups occurred independently of changes in capacity. It is concluded that bladder perfusion at capacity is significantly impaired in interstitial cystitis.