The Role of Intraabdominal Pressure in Venous Blood Drainage from the Prostate into the Vertebral Vein System.

Abstract

We investigated venous blood drainage from the prostate into the vertebral vein system by cineangiography in five mongrel dogs and measured intraabdominal pressure and venous blood pressure in the dog or human to study the role of intraabdominal pressure in the drainage. The averages of intraabdominal pressure and caudal vena caval pressure in the dog were 32.2 +/- 3.0 and 12.8 +/- 1.3 mmHg, respectively, in the supine position, and 39.2 +/- 3.0 and 23.8 +/- 4.0 mmHg, respectively, in the head-up tilt position, when the radiopaque medium injected into the dorsal penile vein appeared in the vertebral vein system. Intraabdominal pressure in the head-up tilt position was significantly higher than that in the supine position when the venous drainage into the vertebral veins happened. In eight continuous ambulatory peritoneal dialysis patients, intraabdominal pressure showed 8.1 +/- 2.4 mmHg in the supine position, 24.6 +/- 4.3 mmHg in the sitting position, and 30.4 +/- 4.9 mmHg in the standing position at rest. During voluntary contraction of the abdominal muscles, the pressure was increased up to 50.6 +/- 21.6 mmHg in the supine position, 69.3 +/- 19.8 mmHg in the sitting position, and 73.8 +/- 19.8 mmHg in the standing position. These pressure values in the human were significantly higher than those observed at the time when the radiopaque medium appeared in the vertebral veins in both supine and head-up tilt positions in the canine. These results suggest that the increase of intraabdominal pressure causes inflow of prostatic venous blood into the vertebral veins via the inferior vena cava, common iliac vein, or internal iliac vein.

Possible role of the internal vertebral venous plexus during exercise in humans

“…The effects of posture on intra-abdominal pressure in humans have been investigated in some clinical cases (Hering et al, 2001;Kiefer et al, 2001;Park, 2000;Suzuki et al, 1993). In a supine position, mean intra-abdominal pressure of mechanically ventilated patients has been estimated as 10-12 mmHg (Hering et al, 2001;Kiefer et al, 2001), although there were great inter-individual variations.…”

“…It therefore seems that as in Subject A, venous blood existing in the intra-abdominal venous system could be conveyed toward veins in the spinal canal by such a small rise in the intra-abdominal pressure. According to observations made by Suzuki et al (1993) in continuous ambulatory peritoneal dialysis patients, voluntary contraction of the abdominal muscles resulted in an increase of intra-abdominal pressure from 8.1 to 50.6 mmHg in a supine position, and from 30.4 to 73.8 mmHg in a standing position. Thus, during exercise, when the abdominal muscles contract in association with body movements and respiration, the intra-abdominal pressure should periodically increase greatly, which may contribute to transferring venous blood returning from the legs to the IVVP.…”

“…It is quite possible that a portion of the venous blood returning from the legs is conveyed through the IVVP, because of periodic changes in intra-abdominal pressure due to exercise. Indeed, it has been suggested that voluntary contraction of the abdominal muscle elevates intra-abdominal pressure to a level that can cause inflow of intra-abdominal venous blood into the IVVP (Suzuki et al, 1993). The venous blood returning from the legs then warms the tissue in the spinal canal, including the spinal cord, when the blood passes through the highly developed IVVP (Greon et al 1997 well shown to be a component of body thermoregulation, and induce thermoregulatory responses according to thermal stimuli in various species of animals (Necker and Rautenberg, 1975;Hales et al, 1978;Pehl et al, 1997).…”

Extraglandular and intraglandular vascularization of canine prostate

“…Campos et al (1985), Goscicka and Spotz (1986), and Wakui et al (1993) reported on the arterial prostate blood supply. Venous vessels between the prostate and vertebral vessels were later described by Japanese scientists (Suzuki et al, 1991(Suzuki et al, , 1992(Suzuki et al, , 1993. A complete description of prostate extraglandular, intraglandular, and zonal blood vessel distribution and their structure and interaction with the glandular parenchyma was made by Stefanov (1998aStefanov ( , 1999a, , and Stefanov et al ( , 2000.…”

“…Delivery of these androgens is related to the increase of abdominal pressure (Dhabuwala and Pierrepoint, 1977;Dhabuwala et al, 1978;Pierrepoint et al, 1975). The blood from the prostate venous system passes through v. iliaca interna, v. iliaca communis, and v. cava inferior into the vertebral venous system (Suzuki et al, 1991(Suzuki et al, , 1992(Suzuki et al, , 1993. Although the authors incorrectly used the term v. cava inferior (v. cava caudalis according to NAV, 1983), their conclusions may explain the route of the vertebral metastases of prostate cancer.…”