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Commentary: An opportunity for a new look at the Ross autograft

  • Jeremy L. Herrmann
    Correspondence
    Address for reprints: Jeremy L. Herrmann, MD, Division of Thoracic and Cardiovascular Surgery, Indiana University School of Medicine, Riley Children's Health at Indiana University Health, 545 Barnhill Dr, Emerson 215, Indianapolis, IN 46202.
    Affiliations
    Division of Thoracic and Cardiovascular Surgery, Indiana University School of Medicine, Indianapolis, Ind

    Riley Children's Health at Indiana University Health, Indianapolis, Ind
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Published:September 03, 2021DOI:https://doi.org/10.1016/j.jtcvs.2021.08.065
      This proof-of-concept study provides a novel modeling technique for analyzing Ross autograft wall stresses.
      See Article page 1728.
      The famed Italian anatomist Antonio Valsalva is credited for discerning the relationship between eddying aortic sinus blood flow and leaflet closure in the early 1700s.
      • Robicsek F.
      Leonarda da Vinci and the sinuses of Valsalva.
      However, Leonardo da Vinci observed this phenomenon and even developed a functional glass model of the aortic root 2 centuries prior.
      • Robicsek F.
      Leonarda da Vinci and the sinuses of Valsalva.
      ,
      • Isaacson W.
      The aortic valve.
      It is therefore remarkable that 500 years since Leonardo's death, we are provided with a novel technique for examining the form and function of the (neo-) aortic root.
      • Xuan Y.
      • Alonso E.
      • Emmott A.
      • Wang Z.
      • Kumar S.
      • Mongeon F.-P.
      • et al.
      Wall stresses of early remodeled pulmonary autografts.
      The present study entailed a combination of patient-specific geometry and material properties to perform finite element analysis to estimate wall stress at each component of the Ross neoaortic root.
      • Xuan Y.
      • Alonso E.
      • Emmott A.
      • Wang Z.
      • Kumar S.
      • Mongeon F.-P.
      • et al.
      Wall stresses of early remodeled pulmonary autografts.
      Aortic and pulmonary arterial tissues collected at the time of the Ross procedure and were subjected to ex vivo biaxial stretching to generate patient-specific material properties for modeling. Cardiac magnetic resonance imaging studies were obtained 1 year after surgery to reanalyze autograft wall stresses and dimensions.
      The authors observed that wall stresses in all autograft regions were greater than in the native distal ascending aorta though without significant dilatation at 1 year of follow-up. Interestingly, peak first principal stresses were greatest at the sinotubular junction (STJ), especially when Dacron grafts were used to replace the ascending aorta, and areas of peak stresses did not correlate with areas of maximal diameter. More pockets of peak wall stresses were also seen in the STJ region. Less study attention was given to distensibility, although this was reduced at the STJ region when graft reinforcement was used. These results shed new light on the early biomechanical forces exerted upon the autograft neoaortic root. Importantly, the authors aim to follow this cohort longitudinally to generate longer term clinical correlations.
      Important limitations of this study include a very small sample size and lack of baseline clinical data. It is a relatively older patient cohort with 12 of 16 patients (75%) aged 50 years or older. It is unclear how well systemic hypertension was managed particularly, as this can be an important contributor to late autograft dilatation and dysfunction. Clearly, the long-term associations of neoaortic root dimensions, wall stresses, and valve function will need to be followed.
      These data may support the various strategies of supporting the Ross autograft to prevent late dilatation and valve dysfunction. Since 2000, our center has reinforced both the annulus and STJ during the Ross procedure when patient size permits (eg, older adolescent and adult patients) even when replacement of the ascending aorta is not performed.
      • Brown J.W.
      • Ruzmetov M.
      • Shahriari A.P.
      • Rodefeld M.D.
      • Mahomed Y.
      • Turrentine M.W.
      Modification of the Ross aortic valve replacement to prevent late autograft dilatation.
      ,
      • Herrmann J.L.
      • Stram A.R.
      • Brown J.W.
      Ross procedure: how to do it and how to teach it.
      This strategy has helped to mitigate late dilatation and valve incompetence with a 91% 15-year freedom from autograft reintervention.
      • Brown J.W.
      • Ruzmetov M.
      • Shahriari A.P.
      • Rodefeld M.D.
      • Mahomed Y.
      • Turrentine M.W.
      Modification of the Ross aortic valve replacement to prevent late autograft dilatation.
      Others have promoted incorporating the entire root within the sinus segment of a Valsalva graft so as to provide reinforcement of the entire autograft with similarly positive mid-term results.
      • Slater M.
      • Shen I.
      • Welke K.
      • Komanapalli C.
      • Ungerleider R.
      Modification to the Ross procedure to prevent autograft dilatation.
      ,
      • Jacobsen R.M.
      • Earing M.G.
      • Hill G.D.
      • Barnes M.
      • Mitchell M.E.
      • Woods R.K.
      • et al.
      The externally supported Ross operation: early outcomes and intermediate follow-up.
      This conceptually and even artistically work harkens back to the Renaissance Era of Leonardo. While the present work is unfinished in its current stage—as was the vast majority of Leonardo's ideas and projects—there is a hopeful future for completion and direct clinical impact.

      References

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        Wall stresses of early remodeled pulmonary autografts.
        J Thorac Cardiovasc Surg. 2022; 164: 1728-1738.e2
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        Ross procedure: how to do it and how to teach it.
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        Semin Thorac Cardiovasc Pediatr Card Surg Ann. 2005; 8: 181-184
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      Linked Article

      • Wall stresses of early remodeled pulmonary autografts
        The Journal of Thoracic and Cardiovascular SurgeryVol. 164Issue 6
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          The Ross procedure is an excellent option for children or young adults who need aortic valve replacement because it can restore survival to that of the normal aged-matched population. However, autograft remodeling can lead to aneurysmal formation and reoperation, and the biomechanics of this process is unknown. This study investigated postoperative autograft remodeling after the Ross procedure by examining patient-specific autograft wall stresses.
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