Transcatheter Aortic Valve Replacement (TAVR) Explained
What is TAVR?
Transcatheter Aortic Valve Replacement (TAVR) is less invasive method of replacing the diseased aortic valve rather than having open heart surgery (SAVR: Surgical Aortic Valve Replacement). During TAVR a bioprosthetic valve mounted in a stent is passed through a large catheter placed in the femoral artery (or through alternative access) and implanted inside the diseased aortic valve, following which the new valve starts to function immediately.
Who will benefit from TAVR?
Patients with severe aortic stenosis who are elderly (> 70 years of age) and/or higher risk for SAVR due to other co-morbidities. Patients who have symptomatic severe aortic stenosis carry a mortality risk of 50% at 2 years and approximately 30% of all patients with severe aortic stenosis are deemed not suitable candidates for surgery. TAVR is a suitable low-risk alternative and has matured as a procedure, since its inception in 2002 by Prof Alain Cribier in France, and large andomized studies have shown that either it is superior or non-inferior to SAVR in extremely high risk, high risk, intermediate-risk, and low-risk patients as well.
Who will decide on whether a patient should have TAVR or SAVR?
A multidisciplinary Heart Team consisting of the cardiologists, cardiac surgeons, imaging specialists, anesthetists / critical care specialists and the patient along with their family members will be involved in the discussion and the decision will be made based on the best treatment for that particular patient taking into account patients preferred choice of therapy.
How is the procedure performed?
TAVR is performed in a regular catheterization laboratory or hybrid operating room depending on the local availability. Once the diagnosis of aortic stenosis is confirmed by echocardiography, a detailed gated CT scan of the heart and peripheral access is done to decide on the suitable valve type, access choice. The preferred access site for the procedure is trans-femoral whenever feasible. The procedure will be under conscious sedation or general anesthesia, depending on the risk profile of the patient and local support and infrastructure availability. Through a large bore sheath placed in the artery of choice for access, the TAVR valve is crimped and passed over a stiff wire and implanted inside the diseased aortic valve either by balloon dilation or self-expansion depending on the valve type. Immediately the new
valve will start to function.
What are the major risks and contraindications?
Compared to SAVR, the risks of TAVR are less and major risks are less than 5%. There are only a few contraindications where there are difficulties with access, low coronaries or very large annulus, etc. But in young patients, SAVR is still preferred choice of treatment.
Which other valves can be replaced percutaneously?
A failed bioprosthetic valve in any part of the heart (Aortic, Mitral, Pulmonary or Tricuspid) can be replaced by a valve in valve transcatheter heart valve therapy (THV). In pulmonary position (right ventricular outflow tract RVOT) in patients who have undergone patch repair or homograft, if it is failing can be treated by a percutaneous pulmonary valve implantation (PPVI) by pre-stenting the conduits with bare-metal or covered stents
Dr Rajaram Antharaman, Senior Cardiologist, Frontier Lifeline.