3. Aortic Valve Disease
Q: What types of diseases are there in Aortic Valve Disease? What kind of surgery is performed?
In patients with Aortic valve disease (such as aortic stenosis where the valve orifice becomes narrow or aortic regurgitation where the valve leaks), some of them (e.g., aortic regurgitation or aortic root enlargement) can be candidates for valve repair surgery; but their long-term results remain unknown and studies show that tissue valve replacement is more reproducible and reliable. From the viewpoint of safety, valve replacement is popular for aortic valve disease.
Q: What kind of caution we have to have for Aortic stenosis?
Patients with Aortic stenosis especially tight one is a dangerous disease with a chance of sudden death when its signs and symptoms (e.g., chest pain or syncope) become strong. However, after the surgery, the patients’ prognosis improves significantly, and the risk of the surgery itself has become much less than 10 years ago. After the surgery, most patients recovered from their critical conditions before the surgery such as severe heart failure with shock status or critical general condition on ventilator; once they recovered, they survived long-term. Thus, even the patients with critical condition should not give up
their hope to survive.
Q: How about the patients with Aortic regurgitation ?
In patients with Aortic regurgitation, left ventricle suffers from burden and it becomes dilated and less powerful gradually. The patients should be careful about the progression of the disease, since they often have no obvious symptoms until the time when the left ventricle becomes very much impaired. In patients with severely dilated left ventricle, we saved the patients’ life by adding left ventricular restoration surgery etc.. From the viewpoint of safety, however, we recommend early (and safer) surgery before the left ventricle becomes too much destroyed.
Q: How useful and beneficial is reparative surgery of Aortic valve?
We repair the aortic valve when we think it more beneficial for patient than valve replacement. Thus, the results are satisfactory (VHD case 8). However, repaired aortic valve is unknown about its long-term durability. It is thought that aortic valve repair is not as reliable as mitral valve repair. Thus, we limit the indication for aortic valve repair and we repair the valve only when it is for sure beneficial.
Another choice is Ross procedure where the patient’s own pulmonary valve is excised and used to replace the aortic valve. This procedure may be beneficial in some patients, but not necessarily ideal in Japan where the supply of pulmonary homograft is very limited. Thus, Ross procedure is employed only for specific patients such as children or aortic root abscess.
As a result, there are eventually 2 choices in artificial valve, which are mechanical valve and tissue valve; we usually choose more suitable one out of two. (For comparison between mechanical valve and tissue one, please see the page of mitral valve.)
Q: What kind of merits does stentless valve have?
Tissue valve has two different choices; stented valve which has struts to hold the valve cusps and stentless valve which has no strut (VHD Case 9). Generally speaking, stentless valve has bigger valve orifice and better performance, especially for narrow aortic root. In some reports especially from North America, stentless valve helps better recovery of heart and better long-term results. However, stented valve also evolves and the difference between the two types of valves seems less than before.
In our experiences, stentless valve can be implanted with 1-2 larger size than stented valve, and the heart seems more normalized late after the surgery. Also, durability of the stentless valve seems longer than stented valve, but it remains unproved. Implantation of stentless valve is technically more demanding and difficult than stented valve, and only experienced surgeons can do it safely. I personally have experiences of stentless valve from 1987 when clinical trial started in Toronto, and do not need too much extra time compared to stented valve; results of stentless valve are so far satisfactory (our of
over 30 cases of experiences, no hospital death).
Q: What types of surgery are there for Aortic root disease?
In Aortic root surgery, we use Bentall surgery or root reconstruction depending on the anatomy and condition of the patient (VHD Case 10). Among the components of Aortic root (Figure), any component except for cusps can be reconstructed by surgery. Cusps also can be reconstructed or repaired, but its long-term results remains unknown; further study is necessary.
When the Aortic ring or root is too small (e.g., narrow aortic root), Aortic root enlargement as illustrated in the figures are employed, so that an artificial valve with adequate size can be implanted. Recently increasing number of higher-performance artificial valves are
available, and there is less need for Aortic root enlargement than before. However, even nowadays, we occasionally encounter situations where Aortic enlargement is essential. Thus, we regard the enlargement technique is an important back-up manueuver or Safety-net.
We do Aortic root reconstruction surgery (e.g., David procedure or Yacoub one) or its modification for those patients who can expect durability of the valve more than 10 years. For those who cannot necessarily expect durability more than 10 years after reparative surgery, we do Bentall procedure by replacing the valve/root. ; if the patient is over 60 years old, when the patient wishes, we do mini-root (or inclusion) surgery by using stentless valve. The operation gives hemodynamics equivalent to Bentall surgery, but is close to simple valve replacement in invasiveness, since it is free from bleeding and will probably be suitable for possible future redo surgery. Moreover, the mini-root method is probably free from late “root rupture” which has been reported in several centers. When a patient over 80 years old has an indication for Aortic root reconstruction, we do the above surgery safely (VHD case 9).
