TAVR has taken the world by stormSeptember 12, 2018
Dr. Anoop Agrawal
There was one thing common between an 82-year-old patient on ventilator and dialysis due to cardiogenic shock, an 81-year-old cancer survivor in and out of the intensive care unit due to recurrent cardiac decompensation, a 65-year-old with previous coronary bypass on whom surgeons had reservations against re-do sternotomy and a 75-year-old with an aortic arch that reminded one of calcified rock formations: They all had severe aortic stenosis (AS), were denied life-saving surgical aortic valve replacement (SAVR) citing high surgical risk, and they all walked home after a smooth uncomplicated transcatheter aortic valve replacement (TAVR or TAVI).
TAVR can easily be considered the most disruptive medical innovation in cardiovascular medicine after coronary stents. The ability to implant a 26 mm transcatheter valve (THV) through a 6 mm suture-less skin incision, without damaging the THV structure is as fancy as it sounds. Since its first human use in the year 2002, TAVR has been extensively scrutinized in high-quality randomized clinical trials across various patient scenarios with a common final conclusion: TAVR performed equal or better compared to the standard of care. Hemodynamic performance of THV is superior to a surgical valve. This, added to the fact that the majority of patients with TAVR don’t require blood thinners, makes it a very attractive choice. It is gratifying to be able to offer a therapeutic option to patients with AS who otherwise are left with no viable alternative if their surgical risk is high. In the lower-than-extreme-surgical-risk subset, having an option of minimally invasive therapy that is equal to, or better than, conventional therapy empowers our patients to make a well-informed decision.
While TAVR, for reasons mentioned above, may be favored by many as the default option for all AS patients, there are a few obstacles to the widespread adoption of TAVR. First, although TAVR has a lower risk profile compared to SAVR in intermediate to extreme surgical risk patients; the same cannot be said with certainty for low surgical risk patients. PARTNER 3 is an ongoing large multi-center trial aimed to study TAVR performance in low surgical risk patients. Second, we should be able to do better on issues like a para-valvular leak and the need for pacemaker implantation. Third, the longevity of THV has not been extensively studied yet since early TAVR implantation was performed on patients in their 8th or 9th decade of life.
TAVR has taken the world by storm. Since its commercial approval, more than 3 lakh implantations have been performed worldwide. More than 40,000 implants are being performed in the United States annually, and TAVR volumes have surpassed SAVR volumes in many developed countries. The TAVR procedure itself is highly efficient, thus improving the throughput of an established center. A high volume center can easily perform 4-5 transcatheter aortic valve replacements within the daily working hours, compared to 2 surgical procedures. Post-procedure care is also less resource intensive, which allows efficient manpower management. From a patient’s perspective, TAVR is a delight. The majority of the patients get extubated on the operating table itself, spend about 24-36 hours in intensive care, and another 24-48 hours on the general floor, with total hospital stay being 3-4 days. The majority are able to converse and take orally within a few hours of the procedure and are able to walk the next day. The skin incision is suture-less, which at times becomes difficult to spot after a week of the procedure. The need for physical rehabilitation is minimal since the total bed rest time is very short, and unlike SAVR, there is no sternal wound to limit patients’ activity.
The Indian experience with TAVR is restricted to a few centers currently, with approximately 500 cases performed nationwide since the first case in the year 2011. This slow start can be attributed to a few factors. First, there is limited awareness among both patients as well as physicians. Continued medical education sessions can address part of this deficit. Second, the expertise to perform TAVR is restricted to a few centers. India does not have a training center for TAVR. Majority of the physicians in India acquire the skill-set via workshops, simulators, foreign observership, and/or learning on the job with a mentor. A few physicians with dedicated TAVR training from the United States or Europe have relocated to India.
Third, TAVR is cost prohibitive to the majority of the people residing in India currently. A major portion of this cost is related to THV and its support hardware. The procedure itself adds little to the overall cost. As with any new device innovation, one can expect the price of THV to come down in the next few years. Notably, TAVR typically is not associated with high recurring cost after the procedure, as the majority of the patients are put on routine medications and require only general check-ups on follow up.
The landscape of cardiovascular medicine is changing. TAVR has evolved to be one indispensable therapeutic option to patients with AS.
The author is Consultant, Interventional Cardiology, CARE Hospitals, Banjara Hills, Hyderabad