In vitro results of a new minimally invasive aortic valve resecting tool

Aortic valve replacement (AVR) using extracorporeal circulation is currently the treatment of choice for symptomatic aortic stenosis. However, patients with multiple high-risk comorbid conditions may benefit from reduced ECC time by a simplified and faster resection in conjunction with quick sutureless valve implantation.

A prototype of a new minimally invasive aortic valve resection tool equipped with rotating and foldable Nitinol cutting edges was designed. Commercially available aortic valve bioprostheses were artificially calcified (group 1: moderate calcified, n=8, group 2: severely calcified, n=8). In vitro resection was performed using a 21mm cutting blade. Resection time (RT), maximum turning moment (MTM) and number of required rotations (NR) were measured. Furthermore, particle generation during the process of cutting was obtained and quantified.

Aortic valve cutting could be obtained without any complications in all cases. Cutting process resulted in a RT of 15.5+/-3s in group 1 compared to 34.9+/-15s in group 2 (p=0.005), MTM was 3+/-0.6Nm in group 1 compared to 3.5+/-0.6Nm in group 2 (p=0.068) and NR were 30.6+/-2.3 in group 1 compared to 48.1+/-15.5 in group 2 (p=0.007). Particle generation was 1.77+/-0.17g in group 1 compared to 1.41+/-0.44g in group 2 (p=0.047).

These first in vitro results confirm feasibility and accelerated aortic valve resection within 30s. This new concept holds promise for very fast AVR in combination with insertion of sutureless aortic valve prosthesis, targeting for ischemic times less than 10min in the open heart situation. Finally, resection and percutaneous AVR within 1min in the beating heart situation is envisioned.