Discussion
The purpose of the paper is to guide the introduction of TAVI in
regional centres by demonstrating the safe introduction at our centre.
The results above and analysis below is an early indication of good
efficacy and safe practice.
The PARTNER Trials demonstrated rates of Major vascular complication
around 11% and 3.8% risk of stroke in TAVI patients. For accreditation
a centre must demonstrate Major vascular complications less than or
equal to 5 % and CVA/TIA rate less than or equal to 8%. One would
expect based on these numbers to observe between one to two patients
suffering a Major Vascular Complications and one episode of CVA/TIA in a
cohort of 19 patients. All-cause mortality at 30 days for the comparable
cohort in the in the PARTNER Trial was 6.5%, which would equate to one
patient in a 19-patient cohort. The absence of these adverse outcomes in
this study is likely due to the small sample size as well as careful
patient selection. Given this is a pilot program it is subject to its
own form of patient selection bias, in the respect that a developing
program and newly accredited practitioners understandably would be more
discerning and cautious in their patient selection compared. Small
sample size and selection bias aside, these rates observed in this early
program are reassuring that the procedure is being performed safely and
comparably to other centres nationally and internationally.
Similarly the echocardiographic outcome data presented in tables 3 and
4, show promising efficacy in restoring physiological valvular gradients
and function. The PARTNER trial showed rates of 12.2% for moderate to
severe paravalvular leak at 30 days, while in our cohort on 10% of
patients developed moderate paravalvular leak, and there were 0 cases of
severe leak. (3)
If these trends continue, the department will meet ongoing ACOR
accreditation requirements. Unfortunately, due to Corona Virus Disease
-19 (COVID-19) the program was interrupted, hence the small sample size
recorded in this paper. To-date with the re-instated program post
COVID-19 precautions the department has performed 45 TAVIs, with trends
noted as with the first 19 patients.
As the institution has developed, there has been a change in the care
provided to patients as the program becomes more streamlined. At
initiation all patients were admitted to ICU following the procedure, as
the familiarity with the procedure increased, particularly towards the
end of 2019 patients were increasingly admitted to CCU. All
transfemoral, subclavian and anterior thoracotomy TAVIs are routinely
admitted to CCU. Those who receive a hemi-sternotomy are admitted to ICU
routinely. Overtime the post-procedural length of stay has been
shortening. At initiation post operative stay varied considerably
between 2-12 days, now patients are routinely staying between one to two
days post TAVI. Soon, TAVI may become a day procedure at our centre.
The average number of procedures performed in a single session is also
increasing with time. At initiation the team were only able to
facilitate two patients per session, but now are routinely performing
three in a single session. As patient referrals increase with the
developing service this number is also set to increase with time.
Despite the unique demographics of the region, only one patient
identified as Aboriginal in this cohort, which is a drastic
under-representation. It is postulated to be the result of two factors,
the average age of the cohort was approximately 80 years, while the
Average life expectancy of ASTI people in regional Australia is between
65-75 years. Additionally, in regional and rural Australia, there is
considerable epidemiological difference in the valvular pathology
encountered in the ASTI and non-ASTI population, were it is common for
ASTI people to present younger with other valve pathology such as
infective endocarditis or rheumatic heart disease.(8) This speaks to the
health inequality across Australia and particularly between the
Indigenous and non-Indigenous Australians. Exemplifying why
decentralisation of TAVI and introduction of a program to
regional/remote Australia is an important step forward in cardiac and
public health.
While the program is running well at the present time, the drive for
improvement into the future is strong. The department moving forward are
trailing new delivery systems for more ergonomic and effective
deployment. This may further improve rates of paravalvular leak. Drafts
of a standardized anti-coagulant and anti-platelet guideline post TAVI
are being written with the recent publishing of the POPULAR Trial.(9)
The department are actively upskilling other practitioners to increase
the number of TAVI competent proceduralist. Concurrently the existing
proceduralists are seeking training and accreditation with a different
valve prosthesis to cater to a wider spectrum of patients, as valve
sizing does limit the current scope of practice. A referral pathway is
being developed and disseminated to the wider referral basin. Ideally,
in the future the development of a Streamlined TAVI clinic may also
occur.