Aortic valve replacement (AVR) and transcatheter aortic valve implantation (TAVI) are invasive procedures where damaged aortic valve is replaced with a new valve to restore its normal function.
The heart consists of four chambers; atria are the smaller upper chambers, and ventricles are the larger lower chambers. There are two valves in each ventricle:
The left ventricle pumps the blood from the heart through the aortic valve into the aorta (the largest artery in the body) and the rest of the body. The aortic valve normally opens during cardiac contraction (systole) to allow the blood flow without any resistance. It closes during cardiac relaxation (diastole) to prevent the blood from leaking back to the heart.
The diseased aortic valve is commonly both stenotic and regurgitating. Both aortic stenosis and aortic regurgitation are diagnosed with echocardiography (transthoracic or transoesophageal echo). Significant aortic valve disease leads to tiredness, breathlessness, chest discomfort, dizziness and blackouts. The heart has to work harder in stenosis to overcome the resistance of the diseased stenotic valve and to pump again the blood, which returned to the left ventricle from the aorta in regurgitation. Both aortic stenosis and aortic regurgitation can ultimately lead to heart failure.
Medication has only a supportive role in treating aortic valve disease (e.g. ACE inhibitors and diuretics in aortic regurgitation). The curative treatment of significant aortic stenosis or regurgitation is valve replacement. There are two options for aortic valve replacement:
The heart is accessed by cutting the sternum (breastbone) and opening the chest. A cardiac perfusion machine (heart-lung bypass) is used to drive the circulation, and the heart is stopped. The surgeon then removes the diseased aortic valve and sutures the prosthesis (metallic or tissue artificial valve) in place. The heart-lung machine is disconnected, and the heart starts beating again. The chest wound is closed with wires and skin sutured with stitches.
Aortic valve replacement is a substantial procedure and carries a risk of mortality and morbidity, including perioperative heart attack, stroke, kidney failure and other complications. Postoperatively, the metallic aortic valve requires anticoagulation with warfarin (NOACs, new oral anticoagulant drugs, such as apixaban, edoxaban, rivaroxaban, or dabigatran can't be used in this indication), and the presence of artificial valves increases the risk of infective endocarditis. However, all these risks are manageable and need to be considered in the context of the very poor prognosis of patients with untreated severe aortic stenosis or aortic regurgitation.