Causes and risk factors
The most common cause of aortic stenosis is calcific degeneration of the valve due to the process of innervation: this usually occurs after the age of 60 years. There are forms of early-onset aortic stenosis, generally associated with congenital forms of valvulopathy such as aortic "bicuspid".
Which are the symptoms?
Mild or moderate aortic stenosis may have no particular symptoms. When aortic stenosis is severe, symptoms usually appear both on exertion and at rest. Among these, the most common are chest pain and loss of consciousness (syncope). As heart fatigue worsens, symptoms such as difficulty breathing, shortness of breath under stress, fluid buildup in the lungs or lower extremities begin to appear.
- chest pain
- loss of consciousness (syncope)
- breathing difficulty
- breathlessness under stress
- accumulation of fluid in the lungs
- accumulation of fluid in the lower limbs
How is it diagnosed?
Aortic stenosis is diagnosed with an echocardiogram: the examination allows to visualize the reduced opening of the valve and determine the severity of stenosis by measuring the gradient (i.e. the pressure difference) between the left ventricle and the aorta and measuring the residual valve area.
How is it treated?
Medications can help control and reduce symptoms in the early stages of the disease, when the extent of stenosis is mild or mild-to-moderate, with monitoring the progression of the disease over time. In case of severe symptomatic aortic stenosis, the only solution is surgery for the implantation of a prosthetic valve.
Calcified aortic valve replacement is done by open-heart surgery, with cardiac arrest and extracorporeal circulation. In most patients, this is the procedure of choice. The native stenotic valve is replaced with a prosthesis, which may be:
- mechanical, robust and durable enough to be considered a permanent solution. The metal materials comprising it require the patient to follow an anticoagulant therapy for life to prevent the formation of clots (embolism).
- biological, composed of material of animal origin. This feature, on the one hand, does not require the patient to follow an anticoagulant therapy, but on the other hand, exposes the prosthesis to wear with the possible need for a reoperation.
SURGICAL INTERVENTION FOR AORTIC STENOSIS
The surgical approaches that can be used are different based on the degree of invasiveness:
the traditional intervention is the one that is performed with total sternotomy, while the so-called minimally invasive approach can be:
- Partial upper sternotomy or mini-sternotomy: is the most common technique involving shorter skin incisions and allows to leave intact a part of the sternum.
- Right anterior mini-thoracotomy: it is accessed through the second intercostal space, with a skin incision of about 5-6 cm, without damaging any bone structure (sternum and ribs). Mini-thoracotomy, compared with mini-sternotomy, has demonstrated better clinical outcomes especially on reducing the incidence of postoperative atrial fibrillation, and reducing ICU and overall hospital stay times.
In the last decade, a fully percutaneous aortic valve implantation technique has been developed. The procedure called TAVI (Transcatheter Aortic Valve Implantation) is performed percutaneously by advancing the prosthesis through a puncture of the femoral artery (leg artery). Therefore, the procedure is performed under local anesthesia, with no need to open the chest with sternotomy and no need for extracorporeal circulation.
TAVI was initially created for patients who were not eligible for traditional surgery due to prohibitive surgical risk, and later excellent results were achieved in patients with high, intermediate and low surgical risk. TAVI is currently the treatment of choice in patients with intermediate or high operative risk and may be considered for all patients aged 75 years or older.