Secinaro A, Milano EG, Ciancarella P, Trezzi M, Capelli C, Ciliberti P, Cetrano E, Curione D, Santangelo TP, Napolitano C, Albanese SB, Carotti A. Eur Heart J Cardiovasc Imaging. 2021 Feb 7:jeab009. doi: 10.1093/ehjci/jeab009. Online ahead of print.PMID: 33550364
Take Home Messages:
- The Ozaki procedure is an alternative to the Ross procedure for AVR in children.
- Short-term hemodynamics of the Ozaki procedure are reassuring.
- Long-term results of the Ozaki procedure are lacking.
Commentary from Dr. Frederic Jacques (Québec City, Canada), section editor of Congenital Heart Surgery Journal Watch:
Aortic valve replacement in children is challenging. Durable prosthesis that allows growth are lacking. The Ross procedure, the actual preferred replacement strategy (creating a double valve concern), offers a reliable aortic valve substitute with growth potential, but it is not devoted of technical challenges and long-term complications. Because of these limitations, an alternative strategy was recently borrowed by congenital surgeons to adult cardiac surgery. This strategy, the Ozaki procedure, literally consists of fashioning a stentless bioprosthesis within the aortic root with pericardium. Said differently, it is a leaflet extension (the less durable aortic valve repair technique) with its origin on the annulus.
In order to define the hemodynamic repercussions of these two aortic valve replacement strategies on the aorta, Secinaro et al. recruited 20 patients (10 per group) and performed a Cardiac MRI to assess flow eccentricity and wall shear stress. They report their findings in the February issue of European Heart Journal – Cardiovascular Imaging. The mean age of patients was 11 years old in each group. Imaging was performed in average 3 years after the Ross procedure and 4 months after the Ozaki procedure. Maximal gradient through the aortic orifice was 7 mmHg for Ross’s patients and 21 mmHg for the Ozaki procedure. Noteworthy regurgitation was present in 40% of patients regardless of the procedure. At the sinotubular junction, 60% of Ross’ had mild eccentricity and 10% of Ozaki’s had marked eccentricity. The remaining had central flow. According to the authors, there was no difference in wall shear stress between the two procedures.
Even if the timing of the performance of the MRI is earlier for the Ozaki procedure group (i.e., less likely to be exposed to deterioration) the reader can appreciate that the hemodynamic performance of the valve (although still within the normal range) is already less favorable than with the Ross procedure. In fact, even though there is less patients with the Ozaki procedure showing mild eccentricity than with the Ross procedure, it shows marked eccentricity in some. Is this the reflection of the material used or is it the repercussions of the inability of surgeons to replicate the “perfection” of a normal native aortic valve? Once again, the Ozaki procedure could be fairly described as a bioprosthesis art crafted within the aorta with the clamp on. Nevertheless, the finding of this stress is in accordance with what is already known for structural degeneration of bioprosthesis and that of leaflet extension. Will this confer less durability to the Ozaki procedure compared to the Ross in the long-term? We will find in a few years. On the other hand, these findings are somewhat reassuring, at least for the short term, regarding the hemodynamics of the Ozaki procedure. Even if it does not beat alternatives such as the Ross, it may actually offer a safe transition to a more definitive surgical replacement (likely adult size manufactured prosthesis) at a later turn. If this is the case, it will already be a major addition to our armamentarium.