Balloon embolectomy catheters in small arteries. II. Comparison of fluid-filled and gas-filled balloons.

Balloon embolectomy catheters were studied in 3 mm dog carotid arteries to compare liquid-filled balloons with gas-filled balloons. Balloons were filled with syringes containing 1 cc fluid (1F), 1 cc gas (1G), and 50 cc gas (50G). Results showed that lateral wall pressures (LWPs) were precisely controlled with fluid-filled balloons but were poorly controlled with gas-filled balloons because gas-filled balloons exhibited spontaneous changes in diameter and LWP. Also, when Edwards 4F balloons were filled in clinically satisfactory criteria, out of direct vision, the following LWPs (in millimeters of mercury) were obtained: 54.4 +/- 8 with 1F, 95.2 +/- 13.8 with 1G, and 216 +/- 19.8 with 50G following balloon inflation; 28.1 +/- 5.7 with 1F and 34.2 +/- 7.1 with 1G following balloon deflation. Balloons filled with 50G collapsed completely during balloon deflation. Statistically lower (P less than 0.05) LWPs were obtained with fluid-filled balloons versus gas-filled balloons and with deflation versus inflation. Gas-filled balloons produced slightly lower shear forces than did fluid-filled balloons (P less than 0.05), but only through regions of stenosis and only at low LWPs-namely 25 and 75 mm Hg LWP. Gas-filled balloons produced no reduction in shear force at higher LWPs. It was concluded that fluid-filled balloons are preferable to gas-filled balloons for use in the operating room because fluid-filled balloons provide lower LWPs greater surgeon control, and only slightly increased shear forces. With both fluid-filled and gas-filled balloons, lower LWPs can be achieved by distending balloons to apparently satisfactory levels and then deflating them to slightly lower levels.