Ozaki Procedure

Last updated date: 12-Jun-2023

Originally Written in English

Ozaki Procedure

Aortic valve disease, which is a general term for illnesses and conditions in which the aortic valve malfunctions, can cause decreased blood flow between the heart and aorta, which can result in disturbed blood flow throughout the body, is treated surgically with the ozaki procedure.

Blood enters and exits the heart with each heartbeat, supplying oxygen-rich blood to organs and tissues throughout the body. Four valves inside the heart carefully control the blood flow from one heart chamber to the next and from the heart to the remainder of the body.

The aortic valve, one of these valves, is situated at the junction of the aorta, the biggest artery in the body, and the left ventricle, the left chamber of the heart. This valve is essential in controlling how blood travels from the heart to the remainder of the body.

The aortic valve depends on its three leaflets, or cusps, to function. These leaflets open to let blood leave the heart and travel to the aorta, and then they close to stop blood from returning to the heart. Serious heart issues, such as heart failure, can arise when the aortic valve encounters a malfunction. Aortic valve replacement and a surgery called aortic valve neocuspidization, or ozaki procedure, are two effective therapies for aortic valve disease.

 

What is Ozaki Procedure?

Aortic valve disease is treated surgically using aortic valve neocuspidization. Sometimes referred to as the Ozaki procedure, it was created and initially described in 2011 by a Japanese surgeon named Shigeyuki Ozaki.

A surgeon performs the ozaki procedure by removing the patient's damaged aortic valve. The aortic valve is then effectively rebuilt by replacing the damaged leaflets with new ones created from tissue obtained from the patient's pericardium, the tissue membrane that covers the heart. The reconstructed valve is placed at the point where the aorta and left ventricle of the heart meet, controlling blood flow. The use of the patient's tissue means no foreign material needs to be implanted, which is a benefit of the operation.

 

Types of Aortic Valve Prostheses

Aortic Valve Prostheses

Most individuals who cannot have their aortic valve repaired have their aortic valve replaced using a mechanical or biological valve prosthesis.

  • Mechanical aortic valve. In particular, younger patients are advised to get the mechanical aortic valve, which is constructed of titanium. To stop blood clots from forming, anticoagulation medication should be taken continuously.
  • The biological aortic valve is often created from cow or pig tissue. Biocompatible implants eliminate the need for lifetime anticoagulant therapy by better integrating with the body's normal blood flow. The majority of biological heart valves, however, require replacement after 8 to 15 years owing to aging and may age even more quickly in young individuals or those with chronic kidney disease. For individuals older than 65, the biological replacement has so far been advised. Young women who are seeking to get pregnant might also be advised to receive a biological aortic valve prosthesis because anticoagulation is related to risks during pregnancy.

 

Before Considering Ozaki Procedure

Physician consult  for Ozaki Procedure

Make sure you are aware of the following before consenting to the test or procedure for your child:

  • The test or procedure's name
  • The purpose of your child's test or treatment
  • What outcomes to anticipate, and what do they signify?
  • The test's or procedure's advantages and disadvantages
  • When and where the test or procedure will be performed on your child?
  • Who will do the surgery and what qualifications do they have?
  • If your child didn't have the test or surgery, what would happen?
  • Are any other tests or procedures to consider?
  • How and when will you receive the outcomes?
  • Whom to contact if you have questions or if your child needs assistance following the test or procedure?
  • Cost of the surgery



Ozaki Procedure Benefits

  • During exercise, the Ozaki valve responds to the needs at hand, much like a healthy aortic valve would. This is especially advantageous for people who are young and energetic patients.
  • The likelihood of inadequate opening (patient-prosthesis mismatch) can be reduced in patients who have a relatively small aortic annulus in comparison to their body mass.
  • Anticoagulation is not required postoperatively.
  • If your valve becomes infected (endocarditis), an Ozaki valve would be a better option.
  • Greater performance of the valve is ensured by the wider surface of coaptation with the Ozaki valve compared to the artificial valve.
  • Even in young patients, the operation delivers a longer-term function with very minimal risk of calcium deposits.

 

Ozaki Procedure Advantages

Ozaki Procedure

Aortic valve replacement surgery has historically been the main treatment for aortic valve disease. An artificial aortic valve is used in place of the patient's natural one during this treatment. A biological prosthesis derived from a donor or an animal may be used as the replacement valve, or it may be a mechanical valve composed of metal or other man-made materials. Although prosthetic valves have helped many people with aortic valve disease live longer and save more lives, they do have some disadvantages. For example, biological valves can deteriorate with time, especially in young individuals, and may require replacement. Contrarily, mechanical valves are more resilient, but their use necessitates the lifelong use of blood thinners (to prevent blood clots), raising the risk of bleeding and other side effects.

Possible alternative therapy for aortic valve dysfunction is the Ozaki procedure. By enhancing blood flow to the aorta, the operation might lessen the symptoms of aortic valve dysfunction and enhance the quality of life. Furthermore, studies show that the reconstructed valve utilized in the Ozaki procedure is reliable and effective at controlling blood flow over the short- and medium-term, thus most patients who undergo the operation don't need to take blood thinners. Ongoing studies are being done to determine how long the Ozaki valve will last and how effective it is.

 

Ozaki Procedure Indications

Ozaki Procedure Indications

There are two primary forms of aortic valve disease, and the Ozaki procedure is used to treat both:

  • When the aortic valve opening narrows, it causes aortic stenosis and makes the heart work harder to pump blood. Less blood than usual enters the aorta and the rest of the body as a result of the narrowed valve.
  • The inability of the valve's leaflets to properly seal leads to aortic regurgitation. Regurgitation, or leakage, occurs when some of the blood that the heart pumps through the aortic valve and into the aorta returns to the heart. To make sure that enough blood is supplied to the aorta and the rest of the body, the heart must exert more effort.

Aortic stenosis or regurgitation can result from several conditions, including:

  • Congenital aortic valve disorder. Only a small fraction of infants are born with cardiac disorders, like aortic valve problems. The most prevalent of them is a bicuspid aortic valve (BAV), which has two rather than three leaflets. Rarely, newborns may have four or only one leaflet when they are born.
  • Aortic valve dysfunction is caused by infective endocarditis, a disease in which bacteria or another pathogen attacks the heart's lining and/or heart valves.
  • Aging. Aortic stenosis or regurgitation can develop over time as a result of the valve's wear and tear, calcium deposits, and hardening of the leaflets.
  • Aortic valve issues can be brought on by other diseases including rheumatoid arthritis, systemic lupus erythematosus (SLE), and rheumatic fever, among many others.

All of the aortic valve diseases listed above can generally be treated with the Ozaki procedure, as can aortic valve issues caused by other diseases. The treatment is ideal for persons under 60 who don't want to undergo an aortic valve replacement procedure to replace their defective aortic valve with an artificial, mechanical valve. Candidates for this procedure include those with aortic valve dysfunction who cannot benefit from aortic valve repair.

 

Ozaki Procedure Preparation

Ozaki diagnosed x-ray

Ask your child's doctor about how to get your kid ready for the Ozaki procedure. Before the surgery, your child shouldn't eat or drink anything after midnight. Beforehand, your kid might need to stop taking any medications. Before the operation, the doctor may want to do a few additional tests on your child. These could consist of:

  • Chest X-ray
  • The electrocardiogram is used to monitor heart rhythm.
  • Blood tests to check overall health
  • Echocardiography to examine the heart and its blood flow.
  • Heart catheterization may be used to measure cardiac and pulmonary pressures or to get a better look at the coronary blood vessels.

Before the procedure, the hair around the surgical site might be removed. About an hour before the procedure, your child may also be given medication to aid with relaxation.

 

How is Ozaki Procedure Performed?

Ozaki surgery

A general anesthetic is used during the Ozaki procedure, so the patient will be unconscious and not experience any pain.

The procedure is started by the surgeon cutting through the breastbone and down the middle of the chest.

The patient's heart is paused during the procedure, and they are then hooked up to a heart-lung bypass machine, which momentarily does the work of the heart and lungs to keep the blood circulating and oxygenated throughout the body.

The pericardium, the sac that surrounds the heart, is cut out after the chest is opened, bathed in a substance called glutaraldehyde, and then washed in a sterile saline solution. The pericardium is reinforced by glutaraldehyde treatment.

The damaged aortic valve is then removed by the surgeon. At this stage, the portion of the pericardium that was taken earlier in the process must be used to create new, replacement leaflets. The glutaraldehyde-treated pericardium is positioned in this way on a flat surface. After that, a template, a stencil, is applied over the tissue. The new leaflets are cut out of the pericardium after the surgeon uses a marker to outline their size and shape. The patient's tissue is used to reconstruct the new aortic valve once the new leaflets have been created and sewn onto the native aortic valve ring.

The heart-bypass machine will be slowly weaned off of the patient. Transesophageal echocardiography, an imaging test, is used by the surgeon to check the functioning of the replaced aortic valve once the patient's heart has resumed beating. In this examination, the heart's beating is observed using sound waves. The surgeon seals the breastbone and then sews up the initial incision once the valve is considered to be in good functional order.

 

Ozaki Procedure Recovery

Ozaki  Recovery

In general, following the procedure:

  • When your child wakes up, he or she can be sleepy and confused.
  • The vital signs of your child will be continuously monitored. His or her heart rate, respiration, blood pressure, and oxygen levels are a few of these.
  • There will be some pain for your child. But the discomfort shouldn't be severe. If necessary, there are painkillers available.
  • After surgery, your child might be ready to drink as soon as the next day. As soon as your child can tolerate them, you can give him or her regular food.
  • Most likely, your child will require a two- to three-week hospital stay.

Once you have left the hospital:

  • Keep in mind that you have follow-up appointments.
  • Your child should be able to resume regular activities rather shortly. However, after the operation, he or she might feel a little more tired.
  • Inquire with your child's doctor about any restrictions on exercise. Children should refrain from physically demanding activities and those that could result in blows to the chest.
  • If your kid gets a fever, increased wound discharge, or any other serious symptoms, contact his doctor right away.
  • Follow all the instructions for medication, physical activity, food, and wound care that your child's doctor gives you.

Most of the time, symptoms subside quickly following surgery. A cardiologist will need to monitor your child for the rest of their life to look out for any potential issues from the treatment. To avoid an infection of the heart valves, your child may also need to take antibiotics before several medical or dental treatments.

 

Ozaki Procedure Complications

Most kids respond favorably to the Ozaki procedure. But difficulties do occasionally arise. Different risk factors may arise depending on your child's age and other health issues. Consult your kid's doctor about the particular risks that your child faces. Possible risks include:

  • Infection
  • Bleeding
  • Irregular heartbeats
  • Blood clots that cause a heart attack or a stroke
  • Heart block. If so, your child might require a pacemaker.
  • Problems resulting from anesthesia

The surgery may occasionally fail. A second operation might be required. Even if the new aortic valve initially functions properly, it may eventually start to leak.  In the future, it will have to be replaced.

 

Conclusion

According to the Ozaki procedure, aortic valve neocuspidization with fixed autologous pericardium is an effective therapy for treating aortic valvulopathies of various entities, including aortic stenosis, aortic regurgitation, and aortic valve endocarditis, in both tricuspid and bicuspid aortic valves. Since mechanical aortic valve replacement requires lifelong anticoagulation, aortic valve neocuspidization with fixed autologous pericardium offers a flexible alternative for difficult aortic valve surgery with n need for anticoagulants. It also has better hemodynamics than biological aortic valve replacement.