Mechanical AVR With Y-Incision Aortic Annular Enlargement

In a previous video on CTSNet, published last year, the authors detailed how to use a “Y” incision and rectangular patch to enlarge the aortic annulus by three to four valve sizes for aortic valve replacement (AVR) with bioprosthesis (1).  

The video below demonstrates the same technique but for mechanical AVR.  

In the case study that follows, the patient presented with a trileaflet aortic valve and severe aortic stenosis (AS). The aortic annulus was enlarged four sizes, from 19 mm to 27 mm, and a size 27 (the largest size) Top Hat mechanical valve was implanted. A CT aortogram at three months post operation showed significantly enlarged aortic root and a well-sited mechanical valve. An echocardiogram showed the mean gradient decreased from 58 to 9 mmHg at the three-month postoperative visit. 

Patient Selection 

The patient was a female with a body height of 155 cm (5’11”), a body weight of 126 kg (277 pounds), a BMI of 52.5 kg/m2, and a body surface area of 2.15 m2. She had symptomatic severe aortic stenosis with a peak gradient of 95 mmHg and a mean gradient of 58 mmHg, and an estimated valve area of 0.72 cm2. She was rejected by transcatheter AVR (TAVR) because of her small aortic root (21.7 mm) and low coronaries (8 mm). The aortic annulus size was measured at 19 mm after the calcified AV was resected. After root enlargement with the “Y” incision, the authors placed a 27 Top Hat mechanical valve (CarboMedics, Austin, TX). The postoperative aortic valve mean gradient was 8 mmHg with no mitral regurgitation and no blood transfusion. The patient was then discharged on postoperative day seven without complications. 

Operative Steps 

1. After the heart was arrested, a partial transverse aortotomy from L-R commissure post to L-Non commissure post was made 1.5 cm above the sinotubular junction, leaving the aorta above the left coronary sinus intact. 
2. The aortic valve was then resected, and the annulus was debrided. The annulus was sized to be 19 mm. 
3. Starting from the posterior end of the transverse aortotomy, a Y-incision was made through the left-non commissure into the aorto-mitral curtain. The Y-incision was extended underneath the left and noncoronary aortic annulus to their respective nadir into the left and right fibrous trigone but did not reach the muscular portion on the left or the membranous septum on the right side. 
4. A rectangular shaped Hemashield Dacron patch was trimmed to 3.5 cm in width and was first anchored to the left fibrous trigone and then sewn to the aorto-mitral curtain/mitral annulus from the left to the right fibrous trigone with running 4-0 Prolene suture. The suture line was transitioned to the undermined aortic annulus at the nadir of both the left and noncoronary sinuses and then was sutured along the longitudinal length of the patch up to the level of the transverse aortotomy incision and secured. 
5. It is difficult to use the mechanical valve sizer for sizing because of the design of the sizers. Instead, the authors used the Magna Ease valve sizer. The largest Magna sizer that could fit was size 27, and it touched the three nadirs of the aortic annulus. So a size 27 Top Hat valve was chosen. The position of the sizer on the patch was marked to guide the placement of valve sutures. 
6. The non-pledgetted 2-0 Ethibond sutures were placed along the native aortic annulus in a noneverting fashion, starting from the right coronary sinus side and from outside in on the patch. 
7. The mechanical valve was placed with the ends of the two discs facing the left-right commissural post, which ensured that the left and right coronary ostia were at the sides of the discs. Then all the valve stitches were passed through the sewing ring. 
8. The sutures at the nadirs of noncoronary and left coronary sinuses, which were the lowest points of the aortic annulus, were tied first to seat the valve well and to prevent paravalvular leak. A portion of the patch beneath the mechanical valve became the new aorto-mitral curtain. 
9. The patch, approximately 2 cm above the mechanical valve, was trimmed into a triangular shape, like a roof. 
10. An additional longitudinal aortotomy was made vertically at the posterior side of the ascending aorta from the posterior end of the transverse aortotomy so that it matched both sides of the triangular shaped patch. 
11. The aortotomy was then closed with the triangular-shaped patch inserted into the longitudinal aortotomy of the proximal ascending aorta with a 4-0 Prolene suture. 

Tips and Pitfalls 

The “Y” incision aortic root enlargement for mechanical AVR was the same as the bioprosthetic AVR (1,2). The key issue was sizing. It was harder to use the mechanical valve sizer to decide the size of the valve, such as Top Hat or St. Jude sizer. Instead, the Magna Ease sizer worked very well. A size 27 Magna Ease sizer has a diameter of 27 mm on one end. It is important to place the sizer supra-annularly, touching all three nadirs of the aortic annulus as shown in the video above. The largest sizer indicated the largest valve the enlarged root could fit. The implantation of the Top Hat mechanical valve was supra-annular, which is the same as for the Magna Ease valve. The implantation of the St. Jude mechanical valve was similar, except the authors use everted pledgetted 2-0 Ethibond suture (3). The orientation of the discs for the St. Jude mechanical valve is the same as the Top Hat valve, with one pivot guard facing the L-R commissure post and the other pivot guard residing on the Hemashield patch.  

Since the aortic root was significantly enlarged, there was plenty of space between the mechanical valve and the coronary ostia, as seen in the video.  

Even though the authors were not preparing the mechanical valve for the future transcatheter aortic valve replacement, the “Roof” technique for aortotomy closure prevented the kick of proximal ascending aorta and preserved the best blood flow pattern through the ascending aorta (4,5). 

References

1. Yang, B. A Novel Simple Technique to Enlarge the Aortic Annulus by Two Valve Sizes. JTCVS Tech. 2021 Feb;5:13-16. Doi: 10.1016/j.xjtc2020.10.038. Epub 2020 Nov 5.
2. Yang B, Naeem A. A “Y” Incision/Rectangular Patch to Enlarge the Aortic Annulus by 4 Valve Sizes in TAV and BAV Patients. April 2021. doi:10.25373/ctsnet.14408741
3. Yang B, Naeem A. A “Y” Incision/Rectangular Patch to Enlarge the Aortic Annulus by 3 Valve Sizes”. Annals of thoracic surgery. March 2021. doi: 10.1016/j.athoracsur.2021.01.072
4. Yang B, Naeem A, Palmer S. “Roof” technique – A modified aortotomy closure in Y-incision aortic root enlargement upsizing 3-4 valve sizes. JTCVS Techniques. April 2022. doi: 10.1016/j.xjtc.2022.01.006
5. Yang B, Ghita C, Palmer S. Y-incision Aortic Root Enlargement with Modified Aortotomy Upsizing the Annulus by 5 Valve Sizes. Annals of thoracic surgery, 2022, in press

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