Modern medicine uses a combination of advanced technology and established knowledge
to reach its ultimate goal: healing patients while limiting risks and preventing disease.
Nevertheless, the growing influence of the economy and capitalist markets on therapeutic
decision-making is yet to be clarified. Consider, for example, the current debate
around the treatment of aortic valve disease. Although surgical aortic valve replacement
(SAVR) has been considered the standard of care in the past few decades, recent years
have seen a substantial rise in the minimally invasive transcatheter aortic valve
replacement (TAVR) technology, even in low-risk surgical patients. Several trials
have compared the outcomes of the two competing therapies in different patient populations.
The results of the Placement of Aortic Transcatheter Valves (PARTNER) 1 trial showed
that Edwards’ TAVR was superior to the standard therapy in patients who could not
undergo surgery, and non-inferior to SAVR in high risk patients in terms of death
at 30 days and 1 year [1,2]. Similar results were obtained by the CoreValve Pivotal
US trial, when investigating Medtronic TAVR in patients with high surgical risk [3,4].
For patients with intermediate surgical risk, Leon et al. [5] showed that TAVR was
comparable to surgical AVR regarding the primary end point of death or disabling stroke.
The evidence from the aforementioned trials was taken into account in 2017, when the
American College of Cardiology/American Heart Association’s Guidelines [6] were updated
to indicate TAVR as class I for high and prohibitive risk patients, and class IIA
for those at intermediate risk.
Although these developments represented a huge step forward for TAVR utilization,
the big leap was only taken in 2019. The Evolut Low Risk (LR) trial [7] showed non-inferiority
of self-expanding TAVR over SAVR in terms of death or disabling stroke at two years
in low surgical risk patients. Similarly, the PARTNER 3 trial [8] demonstrated the
non-inferiority of balloon-expandable TAVR for the composite outcome of death, disabling
stroke, or rehospitalization at one year. These two breakthrough clinical trials led
to the US Food and Drug Administration (FDA) approving the use of TAVR for patients
at low surgical risk, marking a huge shift in the treatment and management of aortic
valve disease.
Despite its rising popularity, some literature has emerged to challenge the implementation
of TAVR. A meta-analysis published by Barili et al. [9] found that, despite the significantly
lower incidence of death in the first year after valve implantation in the TAVR group,
TAVR was a risk factor for all-cause mortality after 40 months. Additionally, Kaul
[10] raised questions about the bias of the Evolut LR and PARTNER 3 trials, concluding
that longer follow-ups and a sufficient number of events will be required to justify
a strong recommendation for TAVR in low-risk patients.
To sum up, TAVR has been proven to be more effective than the SAVR standard therapy
in ineligible surgical candidates, as well as high-risk patients. There is some additional
evidence, limited by the shortness of the follow-up, suggesting its non-inferiority
in intermediate and low-risk patients. The advantages of TAVR in ineligible and high-risk
patients are now recognized by the entire scientific community. What is not fully
understood is the reason why great efforts have been made to broaden the indication
of TAVR to low-risk patients, despite the uncertain proof of its long-term superiority
over SAVR. In this context, a recent propensity score analysis at five years showed
that the intermediate and low-risk patient groups treated with TAVR performed significantly
worse than the SAVR group [11].
In attempting to explain the massive adoption of TAVR in recent years, it is worth
characterizing the treatment as more of an advancement in technology rather than technique.
As explained by D’Onofrio and Gerosa [12], technology is a dynamic and ever-evolving
concept, whereas technique is static. Therefore, we expect that further breakthroughs
in TAVR technology will heighten its performance to equal or exceed that of SAVR.
However, this new technology is significantly more expensive than SAVR, while its
actual benefit for some risk profiles remains controversial.
The substantially higher cost of TAVR has prompted several studies to evaluate its
cost effectiveness. A systematic review [13] revealed that TAVR may be medically and
economically justified, if compared to medical therapy, for unsuitable surgical candidates.
However, there is insufficient evidence that economically justifies TAVR over SAVR
in intermediate and low-risk patients. Similar reports [14,15,16] demonstrated that,
in Europe, TAVR is not a cost-effective strategy for intermediate and high-risk patients.
Importantly, TAVR has been found to cost up to twice as much as SAVR, despite not
significantly reducing the mortality rate [17]. In this context, Ailawadi et al. note
that “when a new technology costs more but delivers outcomes inferior to those observed
with established technology, the new technology becomes a dominant technology rather
than a more cost-effective approach” [17]. This situation creates a vicious cycle
in which large companies are prone to invest more in products that bring in more revenue,
thus growing the transcatheter technology market, while the development of surgical
strategies is overlooked. This outcome defines the real risk we are facing: dominant
products may prevail on therapeutic decisions. We firmly believe that medicine must
not lose its ultimate goal of healing patients. History has taught us that every disease
and patient is unique. For this reason, the therapeutic choices must be customized
for each specific clinical case.
Moreover, in the lively debate about the treatment of aortic valve disease, the existence
of minimally invasive AVR (MI-AVR) is often overlooked. In the panorama of cardiac
surgery, MI-AVR has been steadily gaining widespread popularity due its undisputed
advantages of less invasiveness and trauma, faster recovery, and overall improvement
in the patients’ quality of life [18,19,20,21]. Furthermore, it is associated with
reduced transfusion incidence and lower intensive care stay, hospitalization, and
renal failure, compared to conventional AVR [18,19,20]. In addition, the MI-AVR approach,
when associated with the use of modern sutureless (SU) and rapid-deployment (RD) prostheses,
achieves excellent haemodynamic results with reduced cardiopulmonary bypass and cross-clamp
times [21,22]. The combination of these features possibly makes MI-AVR the best compromise
between technique, technology, costs, the reduction of complications and improved
clinical results for some groups of patients.
This provocative vision allows us to emphasize that TAVR, SAVR and MI-AVR are all
good and safe therapeutic options that represent a great achievement for modern medicine.
To achieve the goal of personalizing care and therapies for individual patients, we
believe that TAVR, SAVR and MI-AVR are all tools needed in the bag of the next generation
of cardiac surgeons.