Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots
May 21st, 2017
Full-root aortic valve replacement by stentless aortic xenograft is a viable option in patients with small aortic roots. We describe, a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses, and discuss its limitations and alternative options.
The overall goal of this surgical procedure is to provide a reliable and reproducible full root implantation of stentless aortic xenografts for patients with small aortic roots undergoing aortic valve replacements. The main advantage of this technique is that it is an excellent option to avoid prosthesis patient mismatch in patients who have a small aortic annulus and who are undergoing an aortic valve replacement. This method can also help answer key questions regarding re-implantation of coronary arteries, such as during aortic root surgery.
After surgically accessing the heart through a median sternum and installing a cardiopulmonary bypass, prepare the aortic root for implantation. In summary, use forceps and a number 18 blade to enlarge the aortic opening and transect the aorta with Metzenbaum scissors. Then, verify the presence of the right coronary ostium and the left coronary ostium.
Next, excise the right coronary leaflet, the non-coronary leaflet, and the left coronary leaflet. Finish the preparation with a perpendicular incision from the top of the non-coronary Valsalva sinus wall down to its base. Now, start the proximal anastomosis.
After placing stay sutures above each aortic commissure, start a suture from the outer aspect of the xenograft to the inner aspect, and pass the stitch into the nadir of the left coronary sinus. Place the next stitch two millimeters to the left of the first. Then, with the aid of an assistant, continue the running suture up to the commissure between the coronary sinuses.
Now, start a second suture starting at the aortic annulus two millimeters to the right of the first suture. From the ventricle, pass these stitches outward. Next, place a third suture starting two millimeters to the side of the second suture starting at the sewing ring at the xenograft.
Run the suture to the commissure between the right sinus and non-coronary sinus and put both ends of the third suture on traction. Now, place a fourth suture at the commissure between the right and non-coronary sinus and run it to the middle of the non-coronary sinus. Now, run a fifth suture from the middle of the non-coronary sinus to the commissure between the non-coronary sinus and the left coronary sinus.
Finally, run the last suture from the end of the fifth suture to the end of the first running suture. Once placed, slowly pull the sixth suture until the graft is tight against the aortic annulus;and then, tie the sutures together. Before proceeding, clean out the region around the proximal suture line and coronary ostia.
Inspect the anastomosis for gaps between the bites. Begin the coronary anastomoses by reconnecting the left coronary ostium to the left coronary neo-ostium of the graft. Place the first stitch of a 6/0 polypropylene running suture at the deepest point of the left coronary neo-ostium from the inside out, and pass this stitch to the deepest point of the left coronary ostium from the outside in.
Place the second stitch to the right of the first. Now, continue the suture into the left coronary neo-ostium of the graft and then into the left coronary ostium of the patient. Then, tie the two sutures together.
Next, using a scalpel, create a right coronary neo-ostium in the graft by excising the ligated right coronary of the graft and enlarging the opening horizontally towards the commissure between the right sinus and the non-coronary sinus of the graft. Then, place a running suture at the left end of the lower ridge of the right coronary ostium. Stitch from the inside out and pass the stitch through the neo-ostium, also at the left end of the lower ridge of the right coronary.
Then, pull the tissues together. Pass the second stitch to the right of the first and bring the suture to the middle of the right ridge of the right coronary anastomosis. Now, continue stitching from the left, moving from the outside to the inside of the patient's tissue and from the inside to the outside of the graft tissue.
Once the running suture is completed, tie the ends together. Lastly, put two coronary artery ostial cannulas in place, one into the left coronary ostium and the other into the right coronary ostium for repeat antegrade cardioplegia. Begin the distal anastomosis with a 5/0 polypropylene running suture from the left end of the lower rim and continue it to the middle of the right rim.
Place stitches at regular two-millimeter intervals from the inside out on the graft tissue and from the outside in on the patient's tissue. Now, continue with the left end of the suture placing equidistant stitches on the anterior aspect of the anastomosis from the outside in on the graft and from the inside out on the patient. Once closed, tie together the suture ends.
Now, slowly remove the aortic cross-clamp under gentle aspiration of the left ventricular vent. Then, remove the lung retractor on the right ventricle. The effective orifice area index is determined from the patient's body surface area and can be used to predict prosthesis patient mismatches.
In patient's with small aortic roots, a 19-millimeter stented pericardial valve would result in mismatches. However, by implanting stentless aortic xenografts, the EOAI becomes significantly greater;and mismatch problems are not expected. Surgical data of stentless aortic xenograft implantation in small aortic roots was compared with similar data reported for stented pericardial valves.
Cross-clamp cardiopulmonary bypass and operative times were all longer using the xenografts;however, 30-day morbidity and mortality measures were equally excellent. While attempting this procedure, it is important to remember to sufficiently mobilize the coronary ostium. Don't forget that full root implantation of stentless aortic xenografts can be extremely delicate and precautions, such as even distribution of tension on the proximal anastomosis by multiple semi-continuous sutures, should always be taken.
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Overview
This article discusses a surgical technique for full-root aortic valve replacement using stentless aortic xenografts, specifically for patients with small aortic roots. The focus is on the management of the proximal suture line and coronary anastomoses, highlighting the advantages and limitations of the procedure.
Key Study Components
Area of Science
- Cardiovascular surgery
- Aortic valve replacement
- Stentless xenografts
Background
- Patients with small aortic roots face challenges during aortic valve replacement.
- Prosthesis patient mismatch is a significant concern in these cases.
- Stentless aortic xenografts offer a potential solution.
- Understanding coronary artery re-implantation is crucial during surgery.
Purpose of Study
- To provide a reliable technique for full-root implantation of stentless aortic xenografts.
- To avoid prosthesis patient mismatch in small aortic annulus patients.
- To address key surgical questions regarding coronary artery management.
Methods Used
- Median sternotomy for surgical access to the heart.
- Installation of cardiopulmonary bypass for the procedure.
- Preparation of the aortic root for implantation.
- Use of forceps and a number 18 blade to enlarge the aortic opening.
Main Results
- Successful verification of the right and left coronary ostia.
- Demonstration of the technique's effectiveness in avoiding prosthesis mismatch.
- Discussion of potential limitations and alternative options.
Conclusions
- Full-root aortic valve replacement with stentless xenografts is a viable option.
- The technique addresses significant challenges in small aortic root patients.
- Further studies may explore refinements and alternative methods.
Frequently Asked Questions
Executive Industry Relevance
For patients with small aortic roots undergoing valve replacement, prosthesis-patient mismatch (PPM) remains a critical concern that impacts long-term ventricular function and clinical outcomes. The full-root implantation of stentless aortic xenografts offers a hemodynamically advantageous alternative by enabling larger effective orifice areas without root enlargement, thereby reducing transvalvular gradients and mitigating PPM risk. This technique supports predictive confidence in valve selection for high-risk anatomical subgroups, informing device strategy and surgical planning in structural heart disease interventions.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables hemodynamic assessment of valve designs in anatomically constrained models, supporting target validation for small-root populations.
- Operational Value: Provides a reproducible surgical model to evaluate valve performance metrics such as effective orifice area indexed to body surface area.
Screening & Assay Development
- Scientific Value: Facilitates standardized evaluation of stentless versus stented valve prototypes in preclinical models with small aortic roots.
- Operational Value: Supports assay development for quantifying transvalvular gradients and orifice area as functional endpoints in valve screening.
Translational & Preclinical Research
- Scientific Value: Bridges discovery to preclinical testing by modeling human small-root pathophysiology in valve performance studies.
- Operational Value: Enables risk-adjusted advancement decisions by identifying valve designs that minimize PPM in high-risk subgroups.
Pipeline & Workflow Integration
This surgical approach fits within the preclinical to translational continuum, particularly in valve design evaluation where anatomical fit and hemodynamic performance are critical go/no-go criteria.
- Discovery Biology: Supports hypothesis testing on valve-annulus interaction and flow dynamics in small-root models.
- Screening: Enables standardized assessment of effective orifice area and gradient reduction as key performance indicators.
- Analytics: Provides quantitative hemodynamic outputs (EOAI, gradients) for comparative valve performance analysis.
- Translational Research: Models clinical PPM scenarios to inform valve sizing strategies and device selection thresholds.
- Enterprise Reuse: Establishes a reusable surgical platform for evaluating next-generation bioprosthetic valves in anatomically challenging cohorts.
Operational & Enterprise Impact
- Scientific Value: Reduces mechanistic uncertainty in valve performance prediction for small-anatomy patient populations.
- Operational Value: Enhances reproducibility in preclinical valve testing through standardized root preparation and anastomosis techniques.
- Strategic Value: Informs go/no-go decisions by identifying valve designs that mitigate PPM risk early in development.
- Portfolio Impact: Enables risk-stratified advancement of valve candidates based on hemodynamic performance in high-need subgroups.
Implementation Considerations
- Requires expertise in complex aortic root surgery and coronary anastomosis techniques.
- Demands precision instrumentation for suture placement and tissue handling during proximal anastomosis.
- Necessitates standardized protocols for coronary ostium mobilization and neo-ostium creation to ensure reproducibility.
- Involves adaptation considerations when applying the technique across different xenograft models or tissue types.
- Limited by increased operative time and technical complexity compared to stented valve implantation, as noted in the source.
