Transcatheter aortic valve replacement (TAVR) is picking up more and more momentum with each passing year, but there are still certain times when surgical aortic valve replacement (SAVR) is a better treatment option.
A new analysis in the American Journal of Cardiology focused on that very topic, highlighting several reasons why a heart team may ultimately decide to treat severe aortic stenosis (AS) with surgery instead of TAVR.[1]
“The current evidence supports TAVR as a frontline therapy for treating severe AS,” wrote first author Sukhdeep Bhogal, MD, with the interventional cardiology section at MedStar Washington Hospital Center, and colleagues. “The crucial question remains concerning the subset of patients who still are not ideal candidates for TAVR because of certain inherent anatomic, nonmodifiable and procedure-specific factors.”
Bhogal et al. provided an in-depth look at the evolution of TAVR over the last two decades. They also examined the many patient factors that come into play when cardiologists and the other members of the heart team must choose between TAVR and SAVR. These are 10 instances when it may be the wisest decision to go with SAVR:
1. Bicuspid or unicuspid aortic valve
There is still very little data on the potential impact of treating patients who present with a bicuspid aortic valve (BAV) with TAVR.
“In 2019, the Food and Drug Administration approved TAVR for patients at low risk regardless of valve morphology, even though patients with BAV were excluded from the randomized cohorts of the pivotal trials,” the authors wrote. “To date, there remain no randomized data comparing TAVR with surgery in patients with BAV, and the available data are primarily observational. Moreover, BAV morphology offers unique challenges, with larger annular dimensions and elliptical orifice geometry than those of tricuspid valves.”
Some studies have found that 30-day and one-year mortality are not impacted when a patient presents with a BAV, but there have been signs that the risk of stroke or permanent pacemaker implantation could be heightened for those individuals.
“In contrast, the data on the outcomes of surgery in patients with BAV are excellent, with low (1.5%) hospital mortality and reported 15-year survival rates ranging from 47% to 78%,” the authors wrote.
The team also examined data related to patients who present with a unicuspid aortic valve, noting that there is little evidence on TAVR among these patients. The existing data does suggest, however, that SAVR can be quite successful.
2. Large or small aortic annulus
“Large aortic annulus was initially considered a contraindication to TAVR, but a recent retrospective analysis using third-generation transcatheter heart valves found TAVR feasible in patients with large aortic annuli,” the authors wrote. “However, patients with extra-large aortic annuli are usually young, have a higher prevalence of BAV with concomitant aortopathy, and are outside the range of currently available THV sizes. Insights from the SURTAVI trial showed higher rates of aortic regurgitation (AR) with increasing indexed annulus sizes in patients who underwent TAVR than in those who underwent SAVR.”
Patients with a small aortic annulus (SAA), meanwhile, present a real challenge for clinicians, often leading to severe patient-prosthesis mismatch after TAVR. Other studies have found that SAA patients may face a higher risk of stroke or major vascular complications after TAVR.
3. LVOT calcification
Severe left ventricular outflow tract (LVOT) calcification is associated with multiple treatment challenges, and Bhogal et al. wrote that SAVR appears to be a better fit for this patient population than TAVR. Unless it is believed that surgery would be unsafe for a patient, SAVR “should be the preferred approach,” the group wrote.
4. Younger patients
Even though some younger patients are now being treated with TAVR, the authors emphasized that this can still lead to significant challenges down the road. Even if the TAVR is a success, there is a high risk that the patient will need more interventions in their lifetime. If another procedure will be needed down the road, does it make more sense to begin with TAVR or SAVR? This is a debate that is ongoing throughout the specialty.
Mechanical heart valves can also be used instead of bioprosthetic valves, which have a service life of 20 years or more, but require lifelong anticoagulation.
“In general, shared decision-making is recommended in these scenarios regarding the choice of prosthetic valve by considering several factors, including patient age, values and preferences, reoperation, and weighing the risks and benefits of anticoagulation,” the authors wrote. “SAVR with a mechanical aortic valve prosthesis remains a valid choice in young patients <50 years of age who have no contraindication to anticoagulation and are willing to consider long-term vitamin K antagonist therapy while avoiding the risk of reoperation.”
5. Atrial fibrillation
The authors noted that a patient’s risk of atrial fibrillation (AFib) increases with age just like their risk of severe AS, leading to many TAVR patients with concomitant AFib.
“AFib is observed in up to one-third of patients who undergo TAVR and has been associated with worse outcomes, with increased risk of all-cause and cardiovascular mortality,” the authors wrote.
6. Coronary artery disease
Coronary artery disease (CAD), like AFib, can be quite common among patients who present with severe AS. CT exams can help rule out CAD, but when CAD is identified, the heart team should proceed with a certain degree of caution. Some prior studies have suggested that SAVR and TAVR patients should undergo coronary revascularization, but the authors noted that high-risk patients were excluded in some cases, leading to some confusion about an already very complex scenario.
The treatment of patients who require both coronary revascularization and aortic valve replacement is likely to be a key topic among researchers for years to come.
(Click here to read about a recent study examining TAVR patients who present with CAD.)
7. Mitral, tricuspid or aortic regurgitation
The study’s authors noted that mitral regurgitation (MR), tricuspid regurgitation (TR) and aortic regurgitation (AR) can all present challenges that may make a heart team consider SAVR over TAVR. When it comes to MR, for example, clinicians are still working to determine the best treatment method for patients with concomitant MR and AS. For now, it may be best for certain patients to stick with the combination of SAVR plus mitral valve surgery.
TR, meanwhile, has been linked to higher mortality if treated conservatively in a patient who present with severe AS. And what about AR?
“Until further data are available on safety and feasibility with the latest transfemoral valve designs, SAVR will remain the standard of care in patients with AR,” the authors wrote.
8. Mitral stenosis
Patients presenting with mitral stenosis and AS typically have rheumatic heart disease. There have been some promising signs that these patients can be successfully treated with TAVR, the authors wrote, but “current guidelines recommend that the treatment strategy should be tailored according to the morphology of the valve anatomy and calcification.”
In many cases, SAVR and open commissurotomy or mitral valve replacement may provide the best path forward.
9. Conduction abnormalities
Pressure from TAVR valves pressing against the aortic annulus can put pressure in the neighboring atrioventricular bundle and the left bundle branch. If this happens, it can cause left bundle branch block and high-grade atrioventricular block, which require the implantation of a permanent pacemaker.
This increased risk of requiring a permanent pacemaker can lead to its own clinical challenges. Researchers continue to examine this issue, and new studies are being published regularly, but conduction abnormalities remain a concern, especially among younger patients or those who face a particularly high risk of requiring a pacemaker. In those instances, a heart team may find that SAVR is the best option.
10. Asymptomatic severe aortic stenosis
“The management of patients with asymptomatic AS is not straightforward,” the authors wrote. “Watchful waiting should be considered for patients in the absence of adverse prognostic features.”
SAVR may potentially be favored over TAVR, the team added, if the patient has “abnormal” stress test results or presents with “very severe AS.”
The full American Journal of Cardiology analysis can be read here. The authors cover much more ground than is listed here, detailing even more scenarios where SAVR may be a valid option for treating patients who present with severe AS.
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.