Abstract 19528: Biomechanical Properties of Patient-specific Aortas and Pulmonary Arteries According to Aortic Valve Phenotype: Relevance to the Ross Procedure
Background: Long-term outcomes of the Ross procedure can be limited by late autograft dilatation requiring reoperation. It has been suggested that bicuspid aortic valve is a risk factor for autograft dilatation. The aim of this study is to compare the biomechanical properties of pulmonary arteries according to aortic valve phenotype.
Methods: At the time of surgery, segments of aortic and pulmonary artery wall were harvested according to aortic valve phenotype (n=29 patients). The segments were subjected to displacement-controlled biaxial stretch testing within 8 hours of surgery, in a physiological solution (37 C). Tissue stiffness at an engineering strain of 60% was evaluated, using engineering stress. Histological analyses were performed on the specimens to assess the number of elastic lamellae. Aortic valve phenotype was bicuspid in 18 patients (62%), unicuspid in 7 patients (24%) and tricuspid in 4 patients (14%).
Results: Pulmonary artery circumferential and longitudinal elastic moduli were similar among the 3 populations (Unicuspid: 0.11±0.05 and 0.09±0.03 MPa, bicuspid: 0.10±0.05 and 0.11±0.05 MPa, tricuspid:0.14±0.07 and 0.09±0.05 MPa, p=0.462 and p=0.621 respectively). Aortic circumferential and longitudinal elastic moduli were also similar among the 3 populations (Unicuspid: 0.13±0.01 and 0.12±0.05 MPa , bicuspid: 0.17±0.06 MPa and 0.14±0.06 MPa, tricuspid: 0.09 MPa and 0.11 MPa , p=0.188 and p=0.720 respectively).
Aortic and pulmonary artery thickness were also similar among the 3 populations (Unicuspid: 1.53±0.16 mm and 1.22±0.29 mm, bicuspid: 1.65±0.33 mm and 1.20±0.32 mm, tricuspid: 2.12 and 1.38±0.15, p=0.248 and p=0.566, respectively).
Pulmonary artery lamellae unit count was also similar among the 3 populations (tricuspid: 30 units, bicuspid: 43±9 units and unicuspid: 30 units, p=0.10). The number of elastic lamellae was also similar in aortic specimens (tricuspid: 52 units, bicuspid: 60±11 units, unicuspid: 52 units, p=0.640).
Conclusion: Current findings suggest that the biomechanical properties of pulmonary arteries obtained from patients undergoing the Ross procedure are independent of aortic valve phenotype. These results may have significant impact on the long-term clinical outcomes following this procedure.
Author Disclosures: P. Dionne: None. E. Wener: None. R. Mongrain: None. R. Leask: None. N. Poirier: None. R. Cartier: None. I. El-Hamamsy: None.
- © 2014 by American Heart Association, Inc.