Aortic valve replacement
[1] During the late 1940s and early 1950s, the first surgical approaches towards treating aortic valve stenosis had limited success.
A ball valve prosthesis placed on the descending thoracic aorta (heterotopically) was developed by Hufnagel, Harvey and others to address aortic stenosis, but had disastrous complications.
This first generation of prosthetic valves was durable, but needed intense anti-coagulation, and cardiac hemodynamics were compromised.
Obstruction at the level of the aortic valve causes increased pressure within the heart's left ventricle.
Chronic regurgitation, by contrast, gives the heart time to change shape, resulting in eccentric hypertrophy, which has disastrous effects on the myocardium.
[9] Patients with moderate aortic valve stenosis who need another type of cardiac surgery (i.e. coronary artery bypass surgery) should also have their valve addressed by the surgical team if echocardiography unveils significant heart problems.
[10] Low gradient aortic stenosis with concomitant left ventricular dysfunction poses a significant question to the anesthesiologist and the patient.
Stress echocardiography (i.e. with dobutamine infusion) can help determine if the ventricle is dysfunctional because of aortic stenosis, or because the myocardium lost its ability to contract.
[15] The tissue is treated to prevent rejection and calcification (where calcium builds up on the replacement valve and stops it working properly).
This procedure was first performed in 1967 and is used primarily in children, as it allows the patient's own pulmonary valve (now in the aortic position) to grow with the child.
Mid-term data on the safety and haemodynamic performance of the Inspiris RESILIA aortic bioprosthesis are encouraging.
Guidelines suggest that patient age, lifestyle and medical history should all be considered when choosing a valve.
[13] Surgical aortic valve replacement is conventionally done through a median sternotomy, meaning the incision is made by cutting through the breastbone (sternum).
This machine breathes for the patient and pumps their blood around their body while the surgeon replaces the heart valve.
This can be done with a Y-type cardioplegic infusion catheter placed on the aorta, de-aired and connected to the cardiopulmonary bypass machine.
When the set-up is ready, the aorta is clamped shut with a cross-clamp to stop blood pumping through the heart and cardioplegia is infused.
Pacing wires are usually put in place, so that the heart can be manually controlled should any complications arise after surgery.
These are usually removed within 36 hours, while the pacing wires are generally left in place until right before the patient is discharged from the hospital.
[30][31] After surgical aortic valve replacement, the patient will usually stay in an intensive care unit for 12–36 hours.
[34] Surgery usually relieves the aortic disease symptoms that led the patient to the operating room.
[36][37][38] Combining aortic valve replacement with coronary artery bypass grafting increases the risk of mortality.
[36] Older patients, as well as those who are frail and/or have other health problems (comorbidities), have a higher risk of experiencing complications.
[40] Using this approach, the surgeon replaces the valve through a smaller chest incision (6–10 cm) than that for a median sternotomy.
There is growing evidence that this approach can reduce postoperative morbidity allowing less blood loss, less pain, faster recovery, and a shorter hospital stay with no difference in mortality.
It is delivered to the site of the existing valve through a tube called a catheter, which may be inserted through the femoral artery in the thigh (transfemoral approach), or using a small incision in the chest and then through a large artery or the tip of the left ventricle (transapical approach).
