Impact of contrast agent viscosity on coronary balloon deflation times: Bench testing results

Objectives To assess the impact of viscosity on angioplasty balloon deflation times. Background Lower contrast viscosity could result in more rapid coronary balloon deflation times. Methods We performed a bench comparison of coronary balloon deflation times using 2 contrast agents with different viscosity (ioxaglate and iodixanol), 3 contrast dilutions, and 2 inflation syringe filling volumes. Ten identical pairs of coronary angioplasty balloons were used to conduct each comparison after balloon inflation to 12 atmospheres. Simultaneous deflations were performed under cineangiography. The time to full contrast extraction and the area of contrast remaining after 5-seconds of deflation (quantified by opaque pixel count) were compared between groups. Results The mean time to full contrast extraction during balloon deflation was 8.3±2.5-seconds for ioxaglate (lower viscosity) versus 10.1±2.9-seconds for iodixanol (higher viscosity) (17.4% decrease, P=0.005), with a 35.6% (P=0.004) reduction in contrast area at 5-seconds. Compared to 1:1 ioxaglate-saline mixture, 1:2 and 1:3 ioxaglate/saline mixes resulted in 26.7% (P<0.001) and 39.0% (P<0.001) reduction in mean balloon deflation time, respectively, but at the expense of decreased balloon opacity. Filling the inflation syringe with 5 versus 15-ml of contrast/saline solution was associated with 7.5% decrease in balloon deflation time (P=0.005), but no difference in contrast area at 5-seconds (P=0.749). Conclusions Use of a lower viscosity contrast agent and higher contrast dilution significantly reduced coronary balloon deflation times, whereas use of lower syringe filling volume had a modest effect. Rapid coronary balloon deflation could improve the safety of interventional procedures.