What is TAVR/TAVI?
TAVR/ TAVI means transcatheter aortic valve replacement/ implantation. To understand it better we need to understand the heart valves, their normal function and diseases affecting the heart valves.
What is the function of heart valves?
There are four valves in the heart, two on the left side- aortic and mitral and two on the right side of the heart- pulmonary and tricuspid. They help to maintain the correct direction of blood flow in the heart and the body.
What are the diseases affecting the heart valve?
Heart valves may get narrowed or leaky which is called stenosis and regurgitation respectively.
What is aortic valve stenosis?
Narrowing of the aortic valve is called aortic valve stenosis or aortic stenosis (AS).
What are the causes of AS?
The aortic valve may be defective by birth or might get affected by rheumatic fever or might get affected by degeneration as the body ages.
What is the natural history of AS?
The narrowing progresses slowly over many years from mild AS to critical or severe AS. Further, it takes a few more years to produce symptoms. Severe symptomatic AS, if left untreated has a 5-year survival rate of less than 10%.
What are the symptoms of AS?
As explained above, the patient gets symptoms only when AS is severe. Typically, the symptoms appear on effort and are relieved with rest. Initially, they are present at more than routine activities. As the disease progresses further, they tend to occur at routine activities followed by less than routine activities and finally are present at rest. These include shortness of breath, palpitations, angina and fatigue.
What is the treatment of AS?
Severe symptomatic AS needs to be treated by aortic valve replacement- AVR. It can be done surgically- surgical AVR- SAVR, by opening up the chest or transcatheter way- transcatheter AVR- TAVR/TAVI, without opening the chest- most commonly by the main artery of the leg (transfemoral).
How is SAVR, TAVR/TAVI done and what are their advantages and disadvantages?
SAVR is done under general anesthesia to the patient, opening up the chest, supporting the heart by heart-lung machine, excising the native aortic valve, suturing the surgical heart valve, taking the heart off the heart-lung machine and closing the chest. It is done by a team of doctors consisting of a cardiac surgeon, cardiac anesthetist, perfusionist and nurses.
- General anesthesia
- Chest bone incision
- Heart-lung machine support
- Approximately 3-day ICU stay
- Approximately 7-day hospital stay
- Approximately 1 month to resume full routine activities
TAVR/TAVI is done most commonly under local anesthesia. A large artery of the leg is punctured and a sheath is inserted in it. Collapsed transcatheter heart valve (THV) mounted on a catheter is passed through this to reach the native diseased aortic valve. Thereafter the collapsed THV is expanded. Once expanded, it pushes the native valve leaflets aside and starts functioning. It is done by a team of doctors consisting of structural heart disease interventions specialist, interventional cardiologists, cardiac surgeons, cardiac anesthetist, cath lab technicians and nurses.
TAVR/TAVI doesn’t require
- General anesthesia- most commonly done under local anesthesia
- Chest bone incision- most commonly done from a large artery of the leg- transfemoral
- Heart-lung machine- not required
- Prolonged ICU stay- routinely shifted out of ICU after 12- 18 hours
- Prolonged hospital stay- routinely discharged after 1- 2 days post-procedure
- Prolonged time to resume full routine activities- routinely resumes them after 5-7 days
Who benefits most from TAVR/ TAVI?
Detailed symptom and clinical assessment, lab tests, ECG, 2 D Echo, coronary angiogram and CT heart -TAVR protocol are done as evaluation and then the case is discussed in a heart team meeting. All patients of severe symptomatic aortic stenosis who are elderly (> 65 to 75 years) and have suitable anatomy on CT heart- TAVR protocol are the candidates for TAVR/TAVI. Patients with comorbidities (advanced lung disease, advanced liver disease, advanced kidney disease, malignancies, serious hematological disorders, advanced autoimmune and connective disorders); frail patients; patients with previous AVR, previous valve surgeries, previous CABG, previous heart surgeries and previous chest surgeries benefit the most from TAVR/TAVI as SAVR carries a high risk in such patients.