Anatomy Beats Device: 3D Imaging Reveals What Really Shapes the Mitral Valve After Repair

For patients with severe mitral regurgitation who are too frail for open-heart surgery, transcatheter edge-to-edge repair, or TEER, has become a lifeline. The procedure clips together the two leaflets of the leaking mitral valve, restoring coaptation and dramatically reducing the backward flow of blood into the left atrium. But as the technology has matured, an increasingly urgent question has emerged: when two closely related devices are available, which one should the heart team choose? A new study from the West German Heart and Vascular Center in Essen, published in Clinical Research in Cardiology, offers one of the most detailed answers yet, and its conclusion is strikingly simple: the valve’s own anatomy, not the device, dictates the final result.

The research team, led by Mohammed Abusharekh and Amir Abbas Mahabadi, compared the original PASCAL repair system with its second-generation iteration, the PASCAL ACE, in a cohort of 366 consecutive patients treated between 2019 and 2024. The PASCAL system, developed by Edwards Lifesciences, introduced a central spacer and independent leaflet capture as structural innovations over the earlier MitraClip platform. The ACE version refined the concept further, featuring a reduced profile, narrower paddles, and increased curvature designed to enhance leaflet approximation, improve deliverability, and distribute mechanical stress more evenly in anatomically challenging valves. Until now, however, head-to-head comparative data in real-world practice have been scarce, leaving device selection largely to operator judgment.

The Essen cohort reflected the realities of contemporary practice. Patients had a mean age of 77.7 years, and nearly 58 percent were men. All had moderate-to-severe or severe mitral regurgitation, categorized by etiology as functional, degenerative, or mixed. Crucially, the two devices were not used interchangeably. Patients receiving the ACE device were older, more frequently had atrial fibrillation, and presented with significantly more complex valve anatomy, including bileaflet or multi-scallop prolapse in 25.8 percent of cases compared with 13.1 percent in the PASCAL group. Moderate-to-severe calcification in the grasping area, leaflet clefts, and restricted leaflet mobility were also more common in the ACE cohort. In other words, clinicians were already intuitively reserving the refined device for the hardest cases.

To move beyond intuition, the investigators deployed comprehensive three-dimensional transesophageal echocardiography before and during every procedure. This imaging approach allowed precise planimetric measurement of the mitral valve orifice area, or MVOA, in late diastole at maximal leaflet opening, along with the vena contracta area, anteroposterior and mediolateral annular diameters, annular area, perimeter, and the annular sphericity index. All 3D datasets were analyzed offline by a senior echocardiographer blinded to device type and outcomes, a methodological safeguard that lends considerable weight to the findings. Procedural endpoints followed the Mitral Valve Academic Research Consortium criteria, and statistical analysis included multivariable regression and propensity score matching to address the inherent selection bias of a non-randomized comparison.

The headline result concerns the fate of the valve orifice. Before the procedure, ACE-treated patients had larger baseline orifice areas, a median of 6.55 square centimeters versus 5.87 square centimeters in the PASCAL group. After the first device was implanted, the ACE group predictably retained a larger residual orifice, 3.81 versus 3.38 square centimeters. But when the researchers calculated the relative reduction, the numbers were almost identical: a decrease of 44.5 percent with ACE versus 45.9 percent with PASCAL, a difference that did not reach statistical significance. This pattern held consistently across functional, degenerative, and mixed etiologies. In essence, both devices squeezed the valve by roughly the same proportion; the final orifice size simply mirrored what the anatomy had provided at the start.

The hemodynamic consequences followed the same logic. The transmitral mean pressure gradient, a key indicator of potential iatrogenic mitral stenosis, rose modestly in both groups, with a slightly smaller increase in the ACE cohort, from one to two millimeters of mercury difference, likely reflecting the larger residual orifice areas in that group. This detail matters clinically, because accumulating evidence suggests that a post-procedural mean gradient of five millimeters of mercury or higher predicts worse outcomes. Whether the modest gradient advantage observed with ACE after the first device translates into long-term clinical benefit remains an open question that the study’s authors flag for future investigation.

Annular remodeling told a similar story of convergence. Both devices shifted the mitral annulus from a circular toward a more elliptical geometry, with comparable relative reductions in the anteroposterior diameter and the annular sphericity index. The slightly larger post-procedural annular dimensions in the ACE group, including a small increase in mediolateral diameter, were best explained by the larger baseline annular size rather than any device-specific geometric effect. Notably, no differences in annular sphericity or transmitral gradients emerged across any of the etiological subgroups, reinforcing the conclusion that the two devices exert fundamentally similar geometric influences on the valve apparatus.

One area where the devices diverged was the need for a second implant. ACE-treated patients more often required two devices, 35.9 versus 23.5 percent, and had a larger residual vena contracta area after the first implant, particularly in degenerative regurgitation where multi-scallop prolapse and bileaflet involvement predominated. Yet after the second device, final vena contracta values and percent reductions were comparable between groups, supporting multi-device strategies as a reliable path to procedural optimization regardless of starting anatomy. Procedural success was uniformly excellent, 100 percent with ACE and 99.6 percent with PASCAL, with no cases of single leaflet device attachment, leaflet injury, or chordal entrapment in either cohort.

The study also documented a clear temporal shift in practice. In the early years, the original PASCAL device accounted for the majority of procedures, but after ACE was introduced at the center in August 2020, its utilization climbed steadily and eventually became the dominant choice. This evolution parallels a rising proportion of patients presenting with complex valve morphology and mixed etiologies, suggesting that the refined device arrived just as the treated population was becoming more challenging. A sensitivity analysis comparing the first fifty PASCAL cases with later ones showed that operator experience improved acute efficacy without compromising safety, partially addressing concerns about a learning curve.

Perhaps the most consequential finding came from the multivariable analysis. After adjusting for age, atrial fibrillation, ejection fraction, etiology, anatomical complexity, baseline dimensions, and temporal trends, the differences in post-procedural orifice and vena contracta areas that appeared in the crude comparison vanished entirely. Device type was not an independent predictor of any geometric or hemodynamic outcome. A stratified analysis by baseline valve size added nuance: device-specific effects on narrowing only emerged in mid-sized valves, where ACE proved more area-sparing in the four-to-five square centimeter range, while at the extremes the underlying leaflet anatomy reigned supreme. The authors’ conclusion is unambiguous: baseline valve anatomy, rather than device selection, is the predominant determinant of post-procedural geometry and hemodynamics. For the growing number of heart teams weighing PASCAL against PASCAL ACE, the message is to choose based on the valve in front of them, favoring the ACE’s narrower paddles for complex, restricted, or calcified anatomies and the original PASCAL’s broader coaptation zone where wide leaflet grasping is needed, always guided by meticulous three-dimensional imaging rather than by any assumption that one device is inherently superior.

Subject of Research: Three-dimensional mitral valve geometry and outcomes after transcatheter edge-to-edge repair comparing PASCAL and PASCAL ACE devices

Article Title: Three-dimensional mitral valve geometry after transcatheter edge-to-edge repair: PASCAL versus PASCAL-ACE—implications for devices selection

Article References: Abusharekh, M., Kampf, J., Schindhelm, F., Jürgens, F., Dykun, I., Al-Rashid, F., Totzeck, M., Rassaf, T., & Mahabadi, A. A. (2026). Three-dimensional mitral valve geometry after transcatheter edge-to-edge repair: PASCAL versus PASCAL-ACE—implications for devices selection. Clinical Research in Cardiology. https://doi.org/10.1007/s00392-026-03031-0

Image Credits: AI Generated

DOI: 10.1007/s00392-026-03031-0

Keywords: mitral regurgitation, transcatheter edge-to-edge repair, PASCAL, PASCAL ACE, 3D echocardiography, mitral valve orifice area, annular remodeling, interventional cardiology, degenerative mitral regurgitation, functional mitral regurgitation, device selection, heart team