The transfemoral approach is—by far—the most desirable access route for transcatheter aortic valve implantation (TAVI) for eligible patients; it was used in the TAVI arm of the recently published PARTNER 3 trial, showing superiority over surgical aortic valve replacement in low-risk patients. Results from the National Inpatient Sample Database suggest that transfemoral access is safer and associated with lower in-hospital stay, mortality and costs compared with the transapical approach. In this commentary, Carlo Di Mario reviews how intravascular lithotripsy may enable more patients to undergo transfemoral TAVI.
Additional alternative access techniques for TAVI—such as transaxillary, transcarotid and transcaval access—have been refined but have only been studied in small prospective registries. Their generalisability to all TAVI programmes is unlikely because of the demanding learning curve and hesitation on the part of many centres to embark into alternative access TAVI procedures.
The use of intravascular lithotripsy to alter compliance, allowing successful dilatation in calcified infrainguinal peripheral arterial vessels was reported in a controlled registry. These findings led to the granting of the CE mark and FDA approval for intravascular lithotripsy peripheral balloons up to 7mm in diameter.
Modifying vascular compliance via intravascular lithotripsy in larger suprainguinal vessels, such as the iliac arteries, was initially reported in two cases, and demonstrated feasibility. A recently published 42-patient registry robustly showed high efficacy in allowing transfemoral access for TAVI after intravascular lithotripsy, maintaining excellent overall procedural outcomes including vascular events and perivalvular regurgitation. Key highlights from that registry are below:
- 42 consecutive TAVI patients with prohibitive calcified, stenotic femoral-iliac disease received intravascular lithotripsy
- 100% heavy calcification with a 265.5-degree average maximum arc of calcium
- >90% access was percutaneous and closed with a percutaneous closure system
- 100% transfemoral valve delivery success
- Zero flow-limiting dissections or perforations
- Zero provisional stenting.
The three main obstacles to using the transfemoral route in TAVI are small vessel diameter, excessive vessel tortuosity and the presence of severe peripheral vascular disease of the iliac and/or the femoral arteries. The presence of severe circumferential arterial luminal calcification is a common finding in elderly patients with aortic stenosis and often prohibits any consideration of transfemoral TAVI. Intravascular lithotripsy may represent a straightforward technique to preserve the benefits of reduced morbidity and mortality of transfemoral TAVI in patients with calcified peripheral arterial disease.
Additionally, the ease of intravascular lithotripsy and the familiarity of peripheral vascular angioplasty techniques may allow for TAVI centres of varying levels of experience and volume to adopt a strategy of routine intravascular lithotripsy followed by TAVI in carefully selected patients with prohibitive ilio-femoral anatomy. Such a pathway could theoretically lead to benefits in quality of life, healthcare cost, and procedural morbidity as compared to referral to traditional alternative access TAVI or surgical valve replacement.
Carlo di Mario is at Structural Interventional Cardiology, Careggi University Hospital, Florence, Italy.
