3. aortic disease

Q: What kinds of Aortic diseases need surgery ?

A:  True aneurysm and Aortic dissection (so-called Dissecting Aortic aneurysm) are representative ones.
True aortic aneurysm is a disease where aortic wall becomes weakened and bulge outward; recently it seems increasing in its incidences. If it ruptures, the patient will die quickly, and if thrombi develops in the aneurysm and if it occludes the distal vessels, major problems can happen. For example, if the embolism develops in brain, it results in stroke and is often fatal.

Q: What is Aortic dissection?

A: Aortic dissection is a disease where Aortic wall detaches into 2 (outside layer and inside layer), and the patient suffers from severe chest/back pain when the dissection develops or extends.  In Japan, famous actor Mr. Yujiro Ishihara years ago and more recently Mr. Cha Kato had surgery for the disease.

There are 2 types of disease in Aortic dissection: Stanford Type A and B. Stanford type A dissection has dissection near the heart as shown in the figure, and it requires emergency surgery.  Without surgery, half of the patients die within 2 days after the onset of dissection.

In Stanford type B (Figure) dissection as shown in the figure, the patient usually needs medical treatment to control blood pressure etc.. However, if the Aorta with type B dissection is about to rupture, surgery is necessary.
Here, first we will discuss true Aortic aneurysm.

Q: What types of diseases are there in the true Aortic aneurysm?

True thoracic Aortic aneurysms have 3 types in location: ascending aortic aneurysm, aortic arch aneurysm, and descending aortic aneurysm. 

They often develop together; for example, in the figure, left panel shows ascending-proximal arch aneurysm and right panel distal arch aneurysm. 

In thoracic Aortic aneurysm, if its diameter reaches 6cm the patient needs surgery because of otherwise high chance of rupture. In patients with Marfan’s syndrome, even aneurysm with the diameter of 5cm often has indication for surgery, because it can rupture.  In order to avoid “too late” situation, it is recommended to check CT scan periodically; it does not cause pain for the patient.

In surgery for thoracic aneurysm, aneurysm part of the aorta is replaced by artificial graft usually made of Dacron; depending on the location of the aneurysm, cardiac, brain and/or other organs protection is necessary.  If the aneurysm is localized in the ascending Aorta, the aneurysmal part can be replaced by artificial graft under cardiopulmonary bypass and Aortic cross-clamp. However, if the aneurysm extend distal to the ascending aorta, some kind of hypothermia (just like bear’s hibernation in winter) under cardiopulmonary bypass and additional brain/heart protection is necessary.  Ascending Aortic aneurysm is usually approached from front, while descending Aorta from left side of the chest. Aortic arch aneurysm can be approached from front or left side, depending on the situation.

Q:  How Aortic arch aneurysm can be operated?

Among thoracic aortic aneurysms, Arch aneurysm needs relatively big surgery (Figure, total arch replacement). 

We put emphasis on prevention of embolism/stroke and spinal chord injury, and employ Stepwise Arch First technique with relatively deep hypothermia (Aortic Case 1). 

For patients with less risk of cerebral embolism, we use selective antegrade cerebral perfusion and with a little higher body temperature; the method helps effective hemostasis thereafter.

The figures shows a method to handle Aortic aneurysm which extends from ascending aorta through aortic arch and descending aorta. The method is called “elephant trunk” because it resembles.

The elephant trunk often is stabilized as time passes and protect aneurismal part of aorta, but when necessary surgery or stent graft can be applied to the elephant trunk and the descending aorta.

Patients with Aortic aneurysm with large size die of its rupture if left without surgery, and if rupture develops the patient’s mortality will be eventually 100%.

Thus, we operate even sick patients (e.g., senile or with other organ diseases) by using variety of techniques including organs’ protection.

In acute type A Aortic dissection, eventually all the patients need emergency surgery in which ascending Aorta with/without aortic arch is replaced.  The figure shows a popular method for acute aortic dissection (Hemiarch replacement for proximal arch and ascending aortic replacement).

The way to protect brain and heart is just the same as for true aneurysm. Aortic tissue in patients with Aortic dissection is fragile and more careful handling is necessary (Aortic Case 2).

When Aortic root (i.e., part of ascending Aorta close to heart) is dissected, aortic regurgitation (leaking valve) often develops. It is another reason of emergency surgery for acute Aortic dissection.

Aortic (valve) regurgitation caused by Aortic dissection usually has a good indication for aortic valve repair surgery, which benefit the patient in many ways.  In my personal experiences in the previous hospital, all 20 patients with acute Aortic dissection survived except for one patient who had heart arrest before the surgery;  We believe that if the patient had come to the operation half an hour earlier (i.e., before the heart stops), he could have been saved, and therefore we keep making effort to do public education as well as shape-up the efficient system of treatment.
In type B dissection where descending Aorta etc. is dissected, usually conservative treatment such as control of blood pressure by intravenous drip infusion or medication etc. is recommended. However, if the aorta is dilated, surgery is necessary at least before the aorta ruptures. If the patient is operated by experienced team before rupture it is almost always successful, but if the operation is done after rupture, the results are not good, because of very poor general condition of the patient.

Q:  Is stent graft useful?

Treatment by using stent graft as a joint project with cardiologists is effective in selected patients. 

With this method, folded artificial graft is inserted to Aorta not by surgery but by catheter, and the graft is deployed and fixed in the scheduled part of the Aorta.

It is meritorious for aged patients or patients with other organs’ diseases. There remains room for improvement for this method, it is accumulating excellent results for patients who don’t have physical power to undergo surgery.

If descending aorta is not stabilized by the elephant trunk as shown in the figure, stent graft as a second procedure helps a lot. When the aorta does not fit the stent graft, another operation is carried out.

Q:  What is the “hybrid” surgery for Aortic disease?

Stent graft is relatively new method of treatment, and is making significant progress recently.  For example, those patients who are not indicated for stent graft or surgery, we started hybrid procedure which combined the above 2 methods for sick patients with thoracoabdominal aneurysm especially ruptured one. In the hybrid method, surgical team makes bypass surgery for major arterial branches in the abdomen, and then stent graft can just fix the aorta without worrying about its branches. In my previous hospital we treated 6 critical patients by the hybrid method, and all successful and went home in better condition. The hybrid method will help many patients who are too sick for conventional treatment (Aortic case 3).  As shown above, the hybrid method works well in thoracoabodominal aortic aneurysm, descending aortic aneurysm, and whole thoracic aneurysm after total arch replacement surgery etc.; it decreases invasiveness of treatment for patients.

Q:  What is important to save more patients with aortic aneurysm or dissection?

In the past we saw many patients who had ruptured aneurysm before coming to the hospital; they were eventually dead before the treatment. We try to cooperate with general physicians, internists, cardiologists and ER people so that the patient can reach hospital before the rupture. Especially Aortic dissection needs prompt action because of the very fast progression of the disease; diagnosis and surgery in time can save the patient. True aortic aneurysms usually have no obvious symptoms except for hoarseness, but when it is rupturing, strong back/lumber pain may develop; also, it is important to check chest X-ray and abdominal palpation as a screening.