Techniques of Aortic Valve Repair
J. Scott Rankin MD
General Concepts
Management of aortic valve disease with prosthetic aortic valve replacement using either tissue or mechanical valves has been associated with suboptimal long-term results. In the Duke series of patients treated with isolated aortic valve replacement over the past 23 years, the 10-year survival approximated only 50% (Figure 1), and in most series, valve-related complications occur in up to 5% per year. One solution is increasing application of aortic valve repair, but until recently, stable repair techniques have not been available. With the advent of Schaefers’ “plication stitch” for correction of leaflet prolapse, good long-term results are now obtainable, and virtually all aortic valves with insufficiency can have stable and successful repairs with a very low incidence of late valve-related complications (Figure 2).
Repair Methods
Aortic valve repair techniques can be divided into annuloplasty/root procedures versus methods to correct leaflet prolapse and other leaflet abnormalities. Currently, annuloplasty is accomplished with sub-commissural annuloplasty, closing the top 1 cm of all 3 commissures, as described by Cabrol in 1966 (Figure 3). Leaflet prolapse is corrected with central plication stitches, shortening the leaflet free-edge length adjacent to the Nodulus Arantius with simple 5-0 or 6-0 Prolene sutures (Figure 4). Shortening the leaflet free-edge raises the leaflet and corrects the prolapse, with good long-term stability demonstrated by Schaefers’ group beyond 10-years (Figure 2). It is also important to emphasize Schaefers’ concept of effective height, where raising the prolapsed leaflet to 10 mm above its base achieves excellent long-term outcomes.
Pure Annular Dilatation
In patients with moderate to severe AI from annular dilatation, often undergoing cardiac surgery for other indications such as coronary or mitral valve procedures, aortic valve repair works well. In a multiple valve repair patient, transesophageal echo shows a moderate central aortic valve leak from annular dilatation, but no leaflet prolapse (Figure 5). A complimentary intraoperative test is obtained with injection of cardioplegia into the aortic root, and if the aorta doesn’t hold pressure and the heart fills, as in this case, then the aortic root is opened, and the valve is repaired. In pure annular dilatation, the leaflets have good verticality without prolapse, but simply do not meet in the midline. The only procedure required is commissural annuloplasty (Figure 3), taking deep bites back into the aorta, and closing the top 0.5 – 1.5 cm of all 3 commissures with pledgetted mattress sutures to a measured valve diameter of 19-21 mm. After this simple procedure, the leaflets meet better in the midline with good verticality and coaptation area, and during cardioplegia reinfusion, the aorta now holds pressure, and the heart does not fill. On TEE, the residual leak is trivial (Figure 5), and the valve in this patient has functioned very well long-term.
Bicuspid Aortic Valve
In congenital bicuspid aortic valve of the common type with severe AI (Figure 6), the valve leak is usually caused by prolapse of the fused left and right coronary leaflets. In a typical patient, the leak is eccentric from over the top of the prolapsed fused leaflet - underneath the non-coronary cusp - and tracking beneath the anterior mitral leaflet (Figure 7). The operation is started by performing a commissural annuloplasty of both commissures to reduce the valve annulus to a 19 St. Jude sizer. It is continued by plicating the free-edge of non-coronary leaflet to an adequate effective height (> 10 mm) as the reference. In this regard, the thickened leaflet free-edge acts as a chordae tendineae of the aortic leaflet as it inserts into the aortic commissure, and shortening the free-edge length with simple sutures of 5-0 or 6-0 Prolene raises the leaflet to the proper effective height of >10 mm. Then a spacing suture is placed equidistant from the commissure in the left aspect of both leaflets, adjacent to the Nodulus Arantius - and another is placed on the right (Figure 6). Now, the excess length of the central fused leaflet is easy to quantify, and this area is closed with simple 5-0 Prolene sutures to make the lengths of both leaflets equivalent. Thus, cleft closure and plication are used to raise both leaflets to approximately the same height and length. Then as a final step, the heights are fine-tuned with additional plication stitches. The finished repair is shown in Figure 6. Post-bypass, the leaflets had good effective height and surface area of coaptation. The valve opened well, and there was no residual leak (Figure 7).
Tri-Leaflet Prolapse
In Figure 8, the patient has severe aortic valve insufficiency, and all 3 aortic valve leaflets are prolapsing, producing an eccentric jet. The free-edge of each leaflet is bent down into the ventricle, and again, the procedure is started with a generous commissural annuloplasty, taking deep bites into the aorta and reducing the annulus down to a 19 mm diameter St. Jude sizer. After the annuloplasty, all 3 leaflets are still prolapsing, and plication stitches are taken adjacent to the Noduli Arantii, raising each leaflet to an approximately 10 mm effective height. After plicating all 3 leaflets, one cusp is still a little low, and it is plicated a little further to bring all 3 to the same height. Another concept for consideration is that the leaflet free-edge lengths need to be approximately 5-7 mm longer than valve diameter to produce coaptation; so we try not to reduce leaflet length below 25-26 mm for a 19 mm diameter valve after annuloplasty.
At this point, all 3 leaflets are at the same height and met in the midline. However, so many plication sutures create a rough coaptation surface, and using gluteraldehyde-fixed autologous pericardium, each leaflet is re-surfaced, leaving a small flap in the center to close the central coaptation gap (Figure 8). This technique minimizes residual central jets, which can be a problem with tri-leaflet prolapse repairs. When tested by cardioplegia injection, the leak then is trivial. The valve opens well by echo – and closes with minimal defect, because of the central pericardial flaps (Figure 8). Transesophageal echo obtained 3 years after repair shows stable leaflet position, good closure, excellent opening, adequate effective height, and minimal residual leak (Figure 9).
Mixed Aortic Valve Stenosis and Insufficiency
The next category of aortic valve disease is mixed aortic stenosis and insufficiency. In Figure 10 is a patient with an unusual bicuspid valve, with fusion of the right and non-coronary leaflets. The valve has a 25 mm peak gradient and moderate leak, and is repaired as part of a triple valve repair procedure. The right and non-coronary cusps are fused with a chunk of calcium in the raphe, but the non-fused left coronary cusp is fairly mobile. The calcium is debrided from the raphe using the Cavitron Ultrasonic Surgical Aspirator (CUSA) device, improving mobility of that leaflet. Then a minimal annuloplasty is performed, because the valve is small to begin with. At that point, the fused leaflet is lower than the other, and 3 plication stitches are placed to raise it. At the conclusion, the valve opens better (Figure 10), the leaflets are of equal length and height, and they meet well in the midline. Cardioplegia testing shows only a trivial leak, and the patient and valve have done well long-term.
Finally, tri-leaflet aortic valves with mixed stenosis and regurgitation also require surgery either as a primary or secondary problem (as during multiple valve procedures). In Figure 11 is another patient undergoing a triple valve repair with mixed aortic stenosis and regurgitation. His AR is moderate, and the measured valve area is 0.4 square centimeters. His root diameter by echo is 19 mm, creating a difficult technical issue. Upon inspecting the valve leaflets, they look pretty good, with only strategically placed spicules of calcium at the hinge points and commissures limiting mobility of all three leaflets. These spicules of calcium are removed with the CUSA ultrasonic aspirator in the left coronary leaflet with only minimal leaflet trauma. This improves mobility significantly – then the decalcification is repeated in the right coronary leaflet, and finally, the non-coronary cusp. At that point, the valve leaflets meet pretty well in the midline, but the non-coronary is lower than the others. A plication stitch is placed in that cusp, which raises it up to the level of the others, but moving the Nodulus Arantius to the right opened up a central gap. A plug of pericardium is sutured to that leaflet (arrow), limiting the residual central leak, and as shown in Figure 11, the valve now opens quite well. The residual leak is trivial, with a measured valve area of 2 square centimeters. It should be emphasized that CUSA decalcification of heavily calcified valves is associated with late leaflet scarring and retraction, producing insufficiency in a third. However, in patients with minimal strategically placed calcium such as this, decalcification is quite safe and effective, early and late after surgical therapy.
Conclusion
So to summarize, the combination of commissural annuloplasty, leaflet plication, pericardial leaflet augmentation, and selective ultrasonic calcium debridement allows stable aortic valve repair, perhaps in the majority of patients with aortic valve disease. This approach represents an excellent candidate for improving outcomes over prosthetic aortic valve replacement. Employing aortic valve repair with autologous tissues has the potential for obtaining better late results than ever achieved with artificial valves. So it is clear that aortic valve repair deserves careful attention in future practice, and that the excellent late results obtainable with current techniques justify repairing most aortic valves with insufficiency, as well as selected valves with mixed lesions.
An Intra-Annular ‘Hemispherical’ Annuloplasty Frame
for Aortic Valve Repair (PDF)
A ‘Hemispherical’ model of aortic valve geometry was developed in which normal human cadaveric aortic valve leaflets could be represented as three hemispheres nested within a cylindrical aorta. By mathematically describing the junction between the leaflets and aorta, the normal three-dimensional annular geometry of the aortic valve could be defined. In this study, a prototype annuloplasty frame based on this model was tested as a repair device in isolated porcine aortic root preparations.
Changing Outcome Characteristics of Multiple Valve Surgery in North America: A 15-Year Perspective and Comparison to Single Valve Procedures (PDF)
Purpose: While results in valvular heart surgery seem to be improving, too few multiple valve cases are available in most centers to appreciate changes in outcome. This study examined trends in national results for multiple valve procedures over the past 15 years, within the context of overall valve surgery. Methods: From 1994 through 2007, 623,039 valve procedures were divided into three 5-year periods and grouped into single aortic (A), mitral (M) and tricuspid (T) operations, along with AM, MT, AT and AMT +/- coronary artery bypass grafting. Pulmonary valve surgery was excluded. Trends in baseline characteristics were documented, and logistic regression analysis adjusted for differences in preoperative patient profiles. Outcomes were expressed as unadjusted operative mortality (UOM), adjusted odds ratios for mortality (AORM) and a composite of mortality and major complications (AORC).
