Key result
Creation of an a-v fistula using 20-, 18-, and 16-gauge needles in rats significantly increased shunt flow to 50%, 78%, and 76% of total cardiac output, respectively, compared to 2% in controls.
Why the study?
Does the needle technique for creating an a-v fistula of varying sizes alter hemodynamic responses in male Sprague-Dawley rats?
Does the needle technique for creating an a-v fistula of varying sizes alter hemodynamic responses in male Sprague-Dawley rats?
The needle technique effectively creates a-v fistulas of varying sizes in rats, resulting in proportional increases in shunt flow, cardiac index, right atrial pressure, and heart weight without significantly altering mean arterial pressure or systemic flow.
Rat a-v fistula model enables graded shunt studies in rodents; leaves open translation to human hemodynamics.
The purpose of the present study were to evaluate the needle technique of creating an arteriovenous (a-v) fistula and to quantitatively determine the hemodynamic responses in rats with three different fistula sizes. The fistula was made in male Sprague-Dawley rats between the aorta and vena cava below the renal arteries by using 20-, 18-, and 16-gauge angiocath needles. Five weeks after a sham operation or creation of an a-v fistula, mean arterial blood pressure (MAP), right atrial pressure, shunt flow, cardiac index, systemic flow, individual organ flows, and heart weight were quantitatively determined. All flow measurements were made using radioactive microspheres. The flow to the lungs was used as a measure of shunt flow. The shunt flow in the 20-, 18-, and 16-gauge fistula animals was significantly increased from a value of 2 +/- 1% (SE) to 50.0 +/- 0.1, 78 +/- 3, and 76 +/- 3% of total cardiac output, respectively. Average cardiac index in the 20-, 18-, and 16-gauge fistula animals increased by 105, 270, and 250%, respectively, compared with control. Right atrial pressure and heart weight were increased in proportion to the size of the fistula. MAP in the control and 20-, 18-, and 16-gauge fistula animals was 122 +/- 5, 126 +/- 3, 118 +/- 3, and 111 +/- 4 mmHg, respectively. There were no significant differences in MAP or systemic flow among any of these groups. The calculated total peripheral resistance in all fistula groups was significantly decreased compared with control.(ABSTRACT TRUNCATED AT 250 WORDS)
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Huang et al. (1994) studied Arteriovenous fistula. Creation of an a-v fistula using 20-, 18-, and 16-gauge angiocath needles vs. Sham operation was evaluated on Shunt flow as a percentage of total cardiac output. Creation of an a-v fistula using 20-, 18-, and 16-gauge needles in rats significantly increased shunt flow to 50%, 78%, and 76% of total cardiac output, respectively, compared to 2% in controls.
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