Abstract
1. The objective of the present study was to determine whether arteriovenous anastomoses (AVA) are present in the uterine circulation of conscious, late-pregnant ewes. 2. Twenty late-pregnant ewes were assigned to two groups. In group 1, 15 μm coloured microspheres were injected into the uterine artery of the pregnant horn and the relative proportion of microspheres trapped in the uterus and lungs was determined. The percentage shunting of blood measured by this method was 17 ± 3%, representing a blood flow of 164 ± 39 mL/min (n = 12). Any contribution of ovarian, cervical, rectal and other vascular beds was specifically excluded in this group. 3. In group 2, total uterine capillary flow was measured using the reference blood flow method, by injecting 15 μm microspheres into the heart. Calibrated flow probes, placed on both main uterine ar teries, concurrently measured total uterine blood flow. Total blood flow to the uterus (flow probe) was significantly greater (t = 3.415; P = 0.027) than uterine capillary flow (microspheres), indicating AVA shunting in the uterine circulation. Mean total blood flow to the uterus was 1749 ± 160 mL/min, of which an average 25 ± 5% (n = 5 sheep) was shunted. 4. The percentage AVA shunting for groups 1 and 2 was not significantly different (t = 1.219; P = 0.24) and, when combined, the mean percentage of uterine blood flow passing through AVA in the late-pregnant sheep was determined to be 19 ± 3%. 5. The present study shows that AVA are present and patent in the uterine circulation of late-pregnant ewes and that they account for the shunting of approximately 20% of the uterine blood flow into the maternal venous circulation.
| Original language | English |
|---|---|
| Pages (from-to) | 92-98 |
| Number of pages | 7 |
| Journal | Clinical and Experimental Pharmacology and Physiology |
| Volume | 25 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1 Jan 1998 |
Keywords
- Arteriovenous anastomoses
- Pregnant sheep
- Uterus
Cite this
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Physiological evidence for arteriovenous anastomoses in the uterine circulation of late-pregnant ewes. / Miller, Suzanne L.; Dickson, Kerry; Jenkin, Graham; Walker, David W.
In: Clinical and Experimental Pharmacology and Physiology, Vol. 25, No. 2, 01.01.1998, p. 92-98.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Physiological evidence for arteriovenous anastomoses in the uterine circulation of late-pregnant ewes
AU - Miller, Suzanne L.
AU - Dickson, Kerry
AU - Jenkin, Graham
AU - Walker, David W.
PY - 1998/1/1
Y1 - 1998/1/1
N2 - 1. The objective of the present study was to determine whether arteriovenous anastomoses (AVA) are present in the uterine circulation of conscious, late-pregnant ewes. 2. Twenty late-pregnant ewes were assigned to two groups. In group 1, 15 μm coloured microspheres were injected into the uterine artery of the pregnant horn and the relative proportion of microspheres trapped in the uterus and lungs was determined. The percentage shunting of blood measured by this method was 17 ± 3%, representing a blood flow of 164 ± 39 mL/min (n = 12). Any contribution of ovarian, cervical, rectal and other vascular beds was specifically excluded in this group. 3. In group 2, total uterine capillary flow was measured using the reference blood flow method, by injecting 15 μm microspheres into the heart. Calibrated flow probes, placed on both main uterine ar teries, concurrently measured total uterine blood flow. Total blood flow to the uterus (flow probe) was significantly greater (t = 3.415; P = 0.027) than uterine capillary flow (microspheres), indicating AVA shunting in the uterine circulation. Mean total blood flow to the uterus was 1749 ± 160 mL/min, of which an average 25 ± 5% (n = 5 sheep) was shunted. 4. The percentage AVA shunting for groups 1 and 2 was not significantly different (t = 1.219; P = 0.24) and, when combined, the mean percentage of uterine blood flow passing through AVA in the late-pregnant sheep was determined to be 19 ± 3%. 5. The present study shows that AVA are present and patent in the uterine circulation of late-pregnant ewes and that they account for the shunting of approximately 20% of the uterine blood flow into the maternal venous circulation.
AB - 1. The objective of the present study was to determine whether arteriovenous anastomoses (AVA) are present in the uterine circulation of conscious, late-pregnant ewes. 2. Twenty late-pregnant ewes were assigned to two groups. In group 1, 15 μm coloured microspheres were injected into the uterine artery of the pregnant horn and the relative proportion of microspheres trapped in the uterus and lungs was determined. The percentage shunting of blood measured by this method was 17 ± 3%, representing a blood flow of 164 ± 39 mL/min (n = 12). Any contribution of ovarian, cervical, rectal and other vascular beds was specifically excluded in this group. 3. In group 2, total uterine capillary flow was measured using the reference blood flow method, by injecting 15 μm microspheres into the heart. Calibrated flow probes, placed on both main uterine ar teries, concurrently measured total uterine blood flow. Total blood flow to the uterus (flow probe) was significantly greater (t = 3.415; P = 0.027) than uterine capillary flow (microspheres), indicating AVA shunting in the uterine circulation. Mean total blood flow to the uterus was 1749 ± 160 mL/min, of which an average 25 ± 5% (n = 5 sheep) was shunted. 4. The percentage AVA shunting for groups 1 and 2 was not significantly different (t = 1.219; P = 0.24) and, when combined, the mean percentage of uterine blood flow passing through AVA in the late-pregnant sheep was determined to be 19 ± 3%. 5. The present study shows that AVA are present and patent in the uterine circulation of late-pregnant ewes and that they account for the shunting of approximately 20% of the uterine blood flow into the maternal venous circulation.
KW - Arteriovenous anastomoses
KW - Pregnant sheep
KW - Uterus
UR - http://www.scopus.com/inward/record.url?scp=0031931133&partnerID=8YFLogxK
U2 - 10.1111/j.1440-1681.1998.tb02183.x
DO - 10.1111/j.1440-1681.1998.tb02183.x
M3 - Article
VL - 25
SP - 92
EP - 98
JO - Clinical and Experimental Pharmacology and Physiology
JF - Clinical and Experimental Pharmacology and Physiology
SN - 0305-1870
IS - 2
ER -