“Encouraging” results for transcarotid TAVI

Darren Mylotte
Darren Mylotte

Darren Mylotte (University Hospital Galway, Galway, Ireland) and his co-authors report in JACC: Cardiovascular Interventions that transcatheter aortic valve implantation (TAVI) with transcarotid access is “feasible and is associated with encouraging short- and medium-term clinical outcomes”. In this interview, he explains the need for an alternative access approach to transfemoral and reviews the potential benefits of transcarotid access.

The transfemoral approach is seen as the preferred approach for TAVI. Why is there a need for alternative options?

Indeed, a transfemoral approach should be considered the first option for TAVI. However, a number of patients have iliofemoral anatomy that is not suitable for such an approach. For example, they might have severe femoral or iliac stenosis, calcification, or tortuosity. These anatomical factors continue to present a problem despite the impressive reductions in delivery catheter diameter achieved by most providers of TAVI valves. Therefore, there is a requirement for alternate vascular access for such patients.

What are the potential advantages of transcarotid access in this context?

The transapical approach has been associated with adverse outcomes compared with other access routes—although this data is non-randomised and thus, potential patient selection bias is an inherent flaw. As it is unlikely that there will ever be a randomised trial comparing vascular access routes, operators tend to opt for the routes with which they are most familiar. Any approach that requires the thorax to be opened is inherently more invasive, and may, therefore, be associated with a longer recovery period for the patient. Therefore, there has been a move in Europe to use less invasive methods to deliver the valve—subclavian and carotid; and via the inferior vena cava in the USA. However, it is important not to exchange convenience for safety. Each alternate access approach has both merits and drawbacks, which need to be evaluated on an individual patient and institutional TAVI team level.

What are the potential disadvantages of this approach?

This approach, in appropriately selected patients, is relatively less invasive than either a transapical or direct aortic approach. Instrumenting the carotid artery is, however, associated with a potential risk for stroke; this was a particular focus of our research. Although we did not see high rates of cerebrovascular complications, we must acknowledge that our patient series is relatively small and larger series will be required to confirm our findings. Additionally, the carotid approach requires careful vascular assessment using multislice computed tomography (MSCT) and, to date, magnetic resonance (MR) perfusion scans.

Do you need specific equipment for a transcarotid approach?

No, the only additional equipment required is a cerebral oximetry—to assess cerebral perfusion intraoperatively. Otherwise, it is a straightforward TAVI via arterial cutdown. We would encourage integrating vascular surgeons into the TAVI team for these procedures if the existing team has little experience with the surgical treatment of carotid artery disease.

What were the study’s key messages?

In appropriately selected patients, the transcarotid approach for TAVI (in patients without a transfemoral option) is both feasible and safe.  With a good vascular surgeon providing support for the carotid access, we have found that institutions have become proficient in the transcarotid approach after only three to four cases

What further studies are needed and are there any plans for such studies?

Our study only included 96 patients. This is clearly insufficient to definitely determine the true risk of stroke for this approach, and larger patient series are required. Furthermore, we initially had very strict criteria for choosing this approach: minimum lumen area of the carotid artery > 7mm; no significant carotid artery bifurcation disease; no aortic arch abnormalities (bovine arch etc); and a cerebral MR perfusion scan suggesting adequate perfusion. Whether these stipulations are truly important requires further study, as does the possibility of performing this procedure using local anaesthesia and conscious sedation.

Which patients could be considered for the approach?

Any patient in whom the transfemoral approach is not possible could be considered for a transcarotid approach. However, as previously mentioned, patients must meet strict anatomical criteria as assessed on preprocedural CT/MR imaging to be considered suitable candidates. Therefore, this approach should not be performed in patients who do not meet these criteria.