Temporary caval stenting improves venous drainage during cardiopulmonary bypass.

OBJECTIVES Assess the benefit of temporary caval stenting for remote venous drainage during cardiopulmonary bypass (CPB). METHODS Temporary caval stenting was realized in bovine experiments (65+/-6 kg) by the means of self-expanding (18F for insertion, 36F in situ) venous cannulas (Smartcanula LLC, Lausanne, Switzerland) with various lengths: 43 cm, 53 cm, 63 cm vs. a standard 28F wire armed cannula in trans-jugular fashion. Maximal blood flows were assessed for 20, 25 and 30 mmHg of driving pressure with a motorized table height adjustment system. In addition, the inferior caval diameters (just above its bifurcation) were measured in real time with intra-vascular ultrasound (IVUS). RESULTS Venous drainage (flow in l/min) at 20 mmHg, 25 mmHg, and 30 mmHg drainage load was 3.5+/-0.5, 3.7+/-0.7 and 4.0+/-0.6 for the 28F standard vs. 4.1+/-0.7, 4.0+/-1.3 and 3.9+/-1.1 for the 36F smart 43 cm, vs. 5.0+/-0.7, 5.3+/-1.3 and 5.4+/-1.4 for the 36F smart 53 cm, vs. 5.2+/-0.5*, 5.6+/-1.1* and 5.8+/-1.0* for the 36F smart 63 cm. The inferior vena caval diameters at 30 mmHg were 13.5+/-4.8 mm for 28F standard, 11.1+/-3.6 for 36F smart 43 cm, 11.3+/-3.2 for 36F 53 cm, and 17.0+/-0.1* for 36F 63 cm (*P<0.05 for 28F standard vs. 36F smart 63 cm long) CONCLUSIONS The 43 cm self-expanding 36F smartcanula outperforms the 28F standard wire armed cannula at low drainage pressures and without augmentation. Temporary caval stenting with long self-expanding venous cannulas provides even better drainage (+51%).