• Bigger Is Better: Oversizing THV Improves Hemodynamics and Lowers PVR Incidence

    In patients with annular dimensions suitable for two valve sizes, implantation of a larger SAPIEN 3 transcatheter heart valve (THV) oversized to both annular area and perimeter was associated with lowest incidence of paravalvular regurgitation (PVR) and improved hemodynamics, reports a new analysis from the PARTNER 3 trial.

    Published online Monday and in the Oct. 11 issue of JACC: Cardiovascular Interventions, the study investigated the impact of computed tomography (CT)–based area and perimeter oversizing on the incidence of PVR and valve hemodynamics in patients treated with the SAPIEN 3 device (Edwards Lifesciences).

    Led by Abdul Rahman Ihdayhid, MD, from the University of British Columbia, Vancouver, the team reported that the degree of annular oversizing was inversely related to, and had greatest impact on, reduction of PVR and incidence of post-dilatation and that both area- and perimeter-based oversizing showed a similar inverse relationship and predictive value for the occurrence of PVR.

    “Patients with annular area dimensions that are in between 2 valve sizes present a common clinical dilemma, with device selection often guided by the physician’s discretion,” said Ihdayhid and colleagues. “Our results go further than previous studies and illustrate the potential role of perimeter-based oversizing.”

    They noted that in patients with annular dimensions in between two valve sizes, those who received the larger device “were consistently associated with modest perimeter-based oversizing and significantly lower incidence of PVR.”

    “This finding is also supported by our observation that the lowest incidence of PVR was in patients with a combination of annular oversizing based on area and perimeter, with a 45% relative reduction in PVR compared with patients oversized by area but undersized to perimeter.”

    Study findings

    The authors performed a sub-analysis of the PARTNER 3 (Placement of Aortic Transcatheter Valves 3) trial data to examine the impact of annular oversizing on PVR and valve hemodynamics in patients with low surgical risk and favorable anatomical features.

    The PARTNER 3 trial included 495 low-surgical-risk patients with severe aortic stenosis who underwent THV implantation. THV sizing was based on annular area assessed by CT, with area and perimeter-based oversizing determined using systolic annular CT dimensions and nominal dimensions of the implanted THV.

    Ihdayhid and colleagues reported that of 485 patients with available CT and echocardiography data, mean oversizing was 7.9% for the annulus area and 2.1% for the perimeter.

    An analysis showed that a very low incidence of PVR with a grade of 3 (moderate) or higher was observed (0.6% of population), including patients with minimal annular oversizing.

    Furthermore, the incidence of PVR with a grade of 1 (mild) or higher, alongside need for procedural post-dilatation, was inversely related to the degree of oversizing, said the team, noting that for patients with annular dimensions suitable for two THV sizes, the larger THV with both area and perimeter oversizing was associated with the lowest incidence of PVR of grade 1 or higher (12.0% vs 43.4%; P < 0.0001).

    “Importantly, the lowest incidence of PVR was observed in patients oversized to both annular perimeter and area,” the authors said. “In particular, in patients with annular area dimensions in between 2 valve sizes, implantation of the larger THV size was associated with lower PVR.”

    Furthermore, they noted that oversizing to the left ventricular outflow tract (LVOT) had “minimal association” with the incidence of PVR.

    “Current THV sizing algorithms typically do not account for the dimensions of the LVOT. Our results provide support for this strategy by demonstrating that the degree of area oversizing at the level of the LVOT has minimal impact on the incidence of PVR.

    Ihdayhid and colleagues noted that further studies are now needed to assess whether annular perimeter should be incorporated into balloon-expandable sizing strategies to optimize outcomes following TAVR.

    Reviewing strategy

    Writing in an accompanying editorial, Philippe Garot, MD, from the Institut Cardiovasculaire Paris-Sud at the Hôpital Privé Jacques Cartier, Massy, France, noted that oversizing algorithms were developed for the SAPIEN and SAPIEN XT balloon-expandable devices (Edwards Lifesciences) to balance the risk of PVR against the risk of annular injury.

    “Since then, operators have developed expertise with S3, and deployment techniques have been further standardized. In addition, CT acquisition and interpretation have become more robust with reliable measurements and less interobserver variability,” they said.

    “In this context, a renewal of THVs oversizing strategies is appropriate.”

    The editorialist noted that adjusting balloon filling has been proposed by several teams to optimize device oversizing and decrease the risk of PVR.

    “While most operators follow the manufacturer’s recommendation regarding the use of area-based algorithms for balloon-expandable sizing, perimeter-based measurements may have incremental value in patients with an eccentric or elliptic annulus in whom perimeter and area-derived oversizing is not linear,” he said.

    “Given the current broadening of TAVR indications to include younger and low-risk patients, procedural refinements should be considered imperative in order to achieve optimal results.”


    Ihdayhid AR, Leipsic J, Hahn RT, et al. Impact of Annular Oversizing on Paravalvular Regurgitation and Valve Hemodynamics: New Insights From PARTNER 3. JACC Cardiovasc Interv 2021;14:2158-2169.

    Garot P. Oversizing TAVR in the Low-Risk Era: Is Bigger Still Better? JACC Cardiovasc Interv 2021;14:2170-2172.

    Image Credit: rumruay – stock.adobe.com

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