Overview of Manouguian Procedure
The Manouguian technique is a method to increase the size of a small aortic root, an area in the heart, usually performed when someone needs an aortic valve replacement. This is done when the person’s aortic annulus (the opening where the aortic valve is situated) is quite small. Doctors use various techniques to make the aortic root larger, allowing them to fit a larger aortic valve. This is important because a larger artificial valve reduces the risk of issues like mismatch between the patient and the prosthesis (artificial part) and wear and tear of the valve structure over time. Similarly, a suitable-sized artificial valve considering the body surface area of a patient can decrease the overall health risks and possibility of death.
This process is usually followed when a small aortic annulus is diagnosed, considering the post-surgery complications that can occur due to a mismatch between the body and the artificial part.
In the Manouguian technique, doctors create a cut and extend it towards the back through a junction between the two sections of the heart valve called the left coronary cusp and the noncoronary cusp. This cut can further be extended onto the front leaflet of the mitral valve, which is another valve in the heart.
Other enlargement techniques include the Nicks-Nunez and the Konno-Rastan procedures. The Nicks-Nunez technique also creates a vertical incision through the junction and carries deeper into the heart, allowing for a larger flow out of the aorta. This technique usually allows the placement of a valve one size larger.
On the other hand, The Konno-Rastan technique is a method to enlarge the front area for the blood to flow out of the aorta. Doctors need to be careful while making the incision not to harm the electrical system of the heart or the first branch of the left anterior descending coronary artery, a major blood supplier to the heart.
The main aim of these procedures is to identify small aortic roots early on and take proper actions to enlarge them, which could help avoid potential health issues associated with a mismatch between a patient and the artificial part.
Anatomy and Physiology of Manouguian Procedure
The aortic root is a complex part of your heart. It’s the passage connecting the main pumping chamber (left ventricle) of your heart to the big artery (aorta) that carries blood from your heart to the rest of your body. This special part of your heart maintains stable blood flow conditions even when your body’s needs change. The aortic root consists of multiple parts that work together smoothly to push blood forward and also supply the heart arteries with blood.
The parts of the aortic root include the aortic valve with its half-moon-shaped flaps, bulges known as sinuses of Valsalva, the junction where the aorta gets wider (sinotubular junction), and the aortic ring (aortic annulus). This aortic root has three sinuses or bulges. The one on the left and the one on the right give rise to their respective heart arteries. The third one, known as the noncoronary sinus, does not connect to a heart artery. The aortic valve has three flaps that are named according to their location: left, right, and back. Each flap is separated by a connection called a commissure. The smallest area between the heart’s pumping chamber and the aorta is known as the aortic annulus.
The size and structure of these parts play a large role in the normal functioning of your body, particularly if you have a heart disease. When the aortic valve is being replaced, the size of the new valve should be proportional to the patient’s body surface to maintain the balance of the aortic root.
Sometimes, a mismatch can occur, where the new valve is smaller than a normal human valve. This is known as patient prosthesis mismatch. This can cause an unusually high pressure across the valve. It can interrupt normal blood flow, causing the heart’s ability to maintain output to be compromised. Mismatch has been associated with more heart problems and poorer patient outcomes, especially in patients whose hearts were not working well before surgery. Therefore, it is very important for the doctor to ensure the correct size of the placement of the new valve according to your body’s size to avoid these potential complications.
Why do People Need Manouguian Procedure
A Manouguian procedure might be recommended by your doctor in the following situations:
* If the part of your main heart vessel where the aortic valve is located, called the aortic root, is too small, hard due to calcium build-ups, or scarred and stiff due to fibrosis. This can be common in adults and can lead to issues due to a mismatch between the patient’s body and an artificial heart valve (prosthesis).
* When children need to get their aortic valve replaced but their aortic roots are too small. So, a doctor might recommend this surgery to expand their aortic roots.
* If in the future there might be a need to insert a new valve without having to remove the old artificial valve. This is called a transcatheter aortic valve replacement (TAVR) and sometimes requires an enlarged aortic root for the placement of a larger bioprosthetic valve (artificial valve made of biological material).
The purpose of the Manouguian procedure is basically to make the opening in your heart bigger to fit better-sized artificial heart valves, to avoid complications in the present and future.
Equipment used for Manouguian Procedure
If your doctor needs to use the Manouguian procedure, here’s what is involved:
The operation takes place in a special room called an operating room. It will have various medical equipment, including a machine known as a cardiopulmonary bypass machine. This machine temporarily takes over the function of the heart and lungs during the surgery, allowing the surgeon to operate on a still, non-beating heart.
The surgical team will make sure everything is clean and sterile to prevent infection. This includes wearing special clothes like sterile drapes (covers), gowns, and gloves.
Cardioplegia is used during the operation. This is a special solution that helps to protect the heart by temporarily stopping it.
An echocardiography ultrasound will be used. This is a tool that allows the surgeon to see a detailed image of your heart using sound waves.
A Swan-Ganz catheter, a soft flexible tube, is used to monitor specific heart functions during the operation.
The sternotomy saw is a special tool used to open the chest to reach the heart.
All other necessary supplies, including operative instruments and sutures (special threads used to close wounds or connect body parts), are used in the procedure.
The graft material – a ‘patch’ used in the procedure – could be made from various substances like dacron (a type of plastic), treated bovine pericardium (cow’s heart skin), or polytetrafluoroethylene (a type of polymer).
Who is needed to perform Manouguian Procedure?
A cardiac surgeon, who is a special type of doctor trained in heart surgery, will be in charge of your operation. They’re accompanied by an anesthesia team, who are responsible for making sure you don’t feel any pain during the procedure and keeping you asleep. In addition, a cardiologist will also be present. This is a doctor who specializes in treating heart issues.
The operation room (OR) nursing staff are there to assist and care for your overall needs. A first assistant will be there too, helping the cardiac surgeon directly during the operation. The perfusionist is a crucial team member who makes sure your blood keeps circulating properly when your heart is stopped for the surgery.
Scrub techs, who maintain sterile conditions in the operating room, will also be present. Finally, an echo tech, who runs special tests to create images of your heart, is involved in the team. This multidisciplinary team works together to make sure your surgery goes as smoothly and safely as possible.
Preparing for Manouguian Procedure
Before having a surgery to replace the aortic valve in your heart, it’s necessary to run several tests. A primary method to examine the exit area of your aortic valve involves using an imaging technique called a transthoracic cardiac echo. This area can also be viewed using alternatives like a specific type of ultrasound called transesophageal echo, or by using computed tomography (CT scan) and magnetic resonance imaging (MRI). All of these techniques help doctors visualize and measure your aortic root, the area connecting the aorta to the heart, from multiple angles.
It’s also important for patients to be checked for associated heart conditions, such as coronary artery disease. This may require stress tests and a procedure called left heart catheterization, which is a way of viewing blood flow in your heart. After an examination called cardiac angiogram rules out any immediate need for procedures like coronary bypass grafting or stent insertion, the detailed assessment of your arteries is done to rule out any irregularities. They might also perform an echocardiogram to evaluate the condition and overall function of the left chamber of your heart. Other conditions like subaortic stenosis, a narrowing below the aortic valve, can also be detected and managed during this time through a surgical procedure called myectomy if necessary. CT scans and an echocardiogram can also identify any hardening or bulging in the ascending aorta. In addition, an electrocardiogram, a test that measures electrical activity of your heart, is performed to check for abnormalities such as irregular heart rhythms, which can also be managed during the surgery.
Choosing the type of aortic valve for the replacement surgery is important and should be decided prior to the operation. This decision involves a thorough discussion with you, the patient, considering your expected lifespan and your ability to tolerate blood-thinning medications. If your doctor suspects that the prosthetic valve might not fit or function properly – a situation called patient-prosthesis mismatch – alternative options need to be considered. For example, different types of valves that have larger openings, like newer mechanical valves or stentless bioprosthetic valves, can be used. In some cases, the surgical procedure may be modified to fit a larger prosthetic valve. In other cases, the plan might continue with the originally chosen size of the valve, accepting the risk of mismatch and dealing with the associated conditions accordingly.
Before the surgery, all these considerations have to be taken into account to optimize the chance of a good outcome and avoiding patient-prosthesis mismatch. This means considering the best type of valve and the best surgical technique for you, based on the assessments and results of the pre-operative tests.
How is Manouguian Procedure performed
The patients are taken to the operation room where they are prepared in the standard sterile way. Doctors should look over all pre-operation images, and consider if a procedure to enlarge the aorta should be done, especially if the patient has a small aortic opening. The surgery begins with a cut down the middle of the chest using a special saw. Next, a machine takes over for the heart and lungs (cardiopulmonary bypass).
A small tube may be placed in the left side of the heart to let out air or fluid if needed. After temporarily stopping the blood flow to the heart and cooling it down, doctors can easily see and inspect the heart. A cut across the aorta can be done for a close look at the aortic valve and the base of the aorta (the aortic root). Doctors can then completely remove the aortic valve and examine the aortic opening. The size of the opening and the patient’s body size are then reviewed to decide how big a new valve can be put in using the Manouguian technique. Normally, this procedure allows for a valve 1 to 2 sizes larger.
Once the decision has been made to expand the base of the aorta, either a traditional or a slightly different version of the Manouguian procedure can be performed. In the modern version of the Manouguian technique, a cut is made between two projections, or cusps, of the aortic valve down to the muscle below the aortic valve. In the traditional procedure, the cut is similar but also continues down to the front leaf of the heart’s mitral valve, almost to the free edge of that valve for even further enlargement. It’s important to make sure the cut is in the center of the leaflet.
Next, the newly created opening is filled in with either a patch made from specially prepared cow heart tissue, a piece of the patient’s own heart tissue, or a synthetic patch. The patch is cut into a diamond shape and sewn into place using a continuous thread starting at the top of the reconstructed area, leaving space for stitching in the new heart valve into the opening. This step allows for the biggest incision for placing a new, larger heart valve. At this point, the size of the aortic opening can be measured again.
Afterwards, the stitches securing the valve can be placed around the aortic opening. The new valve can then be sewn into place. The cut in the aorta can be stitched closed using the remaining patch material. If the wall of the left atrium (part of the heart that receives oxygen-rich blood from the lungs) is small and can be closed, it’s closed together with the patch closure. If the left atrium can’t be closed, a second patch will be needed. Using a special ultrasound used during surgery, the newly enlarged aorta and valve can be checked. The patient can then be taken off the heart-lung machine. The chest is then stitched shut, marking the end of the surgery.
Possible Complications of Manouguian Procedure
Studies indicate that there is very little extra risk when performing a technique to enlarge the aortic root, a part of the heart where the aorta is attached. Patients who underwent this technique did show higher illness or death rates around the time of the operation compared to those who didn’t need enlargement. However, if we only look at patients who had aortic valve replacements with and without the enlargement procedure, no significant difference was observed. Interestingly, those who had their aortic root enlarged were less likely to have issues with their artificial heart valve not fitting the patient properly, which is a good thing.
Despite the fact that the procedure might take longer because of the need to temporarily stop the heart’s blood flow, people who underwent this combination of valve replacement and aortic enlargement didn’t have higher rates of heart attack, stroke, the need for a permanent pacemaker, or a need for a repeat operation due to bleeding.
Potential risks of this procedure could include:
* Infection
* Bleeding
* Damage to the aortic outflow tract structures, which are parts of the heart where blood exits
* Damage to the heart’s natural electrical system
* Damage to the mitral valve, which could lead to significant leakage
* Detachment of the patch used to enlarge the aorta
* Malfunction of the aortic valve if the enlargement is too large
* Issues with the artificial valve not fitting the patient properly
* Reduced ability to exercise
* Delayed shrinkage of the left side of the heart.
What Else Should I Know About Manouguian Procedure?
When a person’s aortic valve isn’t functioning properly, doctors can perform a type of surgery called an aortic valve replacement using the Manouguian technique. This surgery enlarges the aortic valve, which can greatly improve the person’s heart function and quality of life. It’s a way to address a common problem with this procedure, where the replacement valve is too small for the patient, leading to less efficient blood flow (a condition known as “patient prosthesis mismatch”).
Some people may worry about the added risks or expenses related to this technique, such as additional time for the surgery or potential complications. However, studies have shown that these concerns are not significant – the time addition is minimal, and it doesn’t increase the cost of the procedure. Even when the walls around the valve are hardened with calcium, a condition that often happens with age, the benefits of avoiding patient prosthesis mismatch outweigh the risks. This technique is considered to be both safe and consistently successful.
However, not all patients are suitable for this type of surgery. For example, if a patient already had surgery on their mitral valve (another heart valve), they might not be a good candidate for the Manouguian or Nicks techniques specifically. The Konno procedure may be an option since it allows for previous mitral valve replacements.
During the surgery, the doctor has to be careful about the size of the replacement valve. If the new valve (or the annulus, the ring-like structure of the valve) is enlarged too much, it could lead to problems with the aortic valve or pressure on the heart’s electrical system, possibly leading to abnormal heart rhythms or even a very slow heart rate (a condition known as heart block).
After the surgery, all patients should have their hearts scanned with a transthoracic echocardiogram (a non-invasive ultrasound exam of the heart) to check the new valve and measure its effectiveness.
To sum up, careful planning and consideration to detail before and during the surgery, combined with the right postoperative care, can bring the best outcome for people undergoing aortic root enlargement – improved cardiac function and a chance for a better quality of life.
