Modeling conduit choice for valve-sparing aortic root replacement on biomechanics with a 3-dimensional-printed heart simulator

Michael J Paulsen; Patpilai Kasinpila; Annabel M Imbrie-Moore; Hanjay Wang; Camille E Hironaka; Tiffany K Koyano; Robyn Fong; Peter Chiu; Andrew B Goldstone; Amanda N Steele; Lyndsay M Stapleton; Michael Ma; Y Joseph Woo

doi:10.1016/j.jtcvs.2018.10.145

Modeling conduit choice for valve-sparing aortic root replacement on biomechanics with a 3-dimensional-printed heart simulator

J Thorac Cardiovasc Surg. 2019 Aug;158(2):392-403. doi: 10.1016/j.jtcvs.2018.10.145. Epub 2018 Nov 15.

Affiliations

¹ Department of Cardiothoracic Surgery, Stanford University, Stanford, Calif.
² Department of Cardiothoracic Surgery, Stanford University, Stanford, Calif; Department of Mechanical Engineering, Stanford University, Stanford, Calif.
³ Department of Cardiothoracic Surgery, Stanford University, Stanford, Calif; Department of Bioengineering, Stanford University, Stanford, Calif.
⁴ Department of Cardiothoracic Surgery, Stanford University, Stanford, Calif; Department of Bioengineering, Stanford University, Stanford, Calif. Electronic address: joswoo@stanford.edu.

PMID: 30745047
DOI: 10.1016/j.jtcvs.2018.10.145

Abstract

Objective: The optimal conduit for valve-sparing aortic root replacement is still debated, with several conduit variations available, ranging from straight tubular grafts to Valsalva grafts. Benefits of neosinus reconstruction include enhanced flow profiles and improved hemodynamics. Curiously, however, some clinical data suggest that straight grafts may have greater long-term durability. In this study, we hypothesized that straight tubular grafts may help maintain the native cylindrical position of the aortic valve commissures radially, resulting in preserved leaflet coaptation, reduced stresses, and potentially improved valve performance.

Methods: Using 3D printing, a left heart simulator with a valve-sparing root replacement model and a physiologic coronary circulation was constructed. Aortic valves were dissected from fresh porcine hearts and reimplanted into either straight tubular grafts (n = 6) or Valsalva grafts (n = 6). Conduits were mounted into the heart simulator and hemodynamic, echocardiographic, and high-speed videometric data were collected.

Results: Hemodynamic parameters and coronary blood flow were similar between straight and Valsalva grafts, although the former were associated with lower regurgitant fractions, less peak intercommissural radial separation, preserved leaflet coaptation, decreased leaflet velocities, and lower relative leaflet forces compared with Valsalva grafts.

Conclusions: Valsalva grafts and straight grafts perform equally well in terms of gross hemodyanics and coronary blood flow. Interestingly, however, the biomechanics of these 2 conduits differ considerably, with straight grafts providing increased radial commissural stability and leaflet coaptation. Further investigation into how these parameters influence clinical outcomes is warranted.

Keywords: aorta; conduit; coronary blood flow; ex vivo modeling; in vitro modeling; leaflet velocity; valve-sparing aortic root replacement; valve-sparing surgery.

Publication types

Video-Audio Media

MeSH terms

Animals
Aorta / pathology
Aorta / physiopathology
Aorta / surgery*
Aortic Valve / pathology
Aortic Valve / physiopathology
Aortic Valve / surgery*
Biomechanical Phenomena
Coronary Circulation
Echocardiography, Transesophageal
Hemodynamics
Models, Anatomic
Printing, Three-Dimensional*
Sinus of Valsalva / pathology
Sinus of Valsalva / physiopathology
Sinus of Valsalva / surgery
Swine
Vascular Grafting / methods