Author + information
- Published online November 15, 2017.
- Nahid El Faquir, MD,
- Ben Ren, MD, PhD,
- Marguerite Faure, MD,
- Marjo de Ronde, RN,
- Patrick Geeve, BN,
- Anne-Marie Maugenest, ICRN,
- Isabella Kardys, MD, PhD,
- Marcel L. Geleijnse, MD, PhD,
- Peter P. de Jaegere, MD, PhD,
- Ricardo P.J. Budde, MD, PhD and
- Nicolas M. Van Mieghem, MD, PhD∗ ()
- ↵∗Erasmus Medical Center, Thoraxcenter, Department of Interventional Cardiology, Room Bd 171, ′s-Gravendijkwal 230, 3015 CE Rotterdam, the Netherlands
Excellent outcome after transcatheter aortic valve replacement (TAVR) is demonstrated by preserved transcatheter heart valve (THV) function at 2 to 5 years and intact structural integrity at 2 years (1,2). Hypoattenuated leaflet thickening (HALT) appears in up to 40% by multislice computed tomography (MSCT) at 30 days post-TAVR (3). Data on long-term THV performance and durability are scarce but imperative to justify the growing implementation in low-risk patients. We aimed to assess stent frame integrity and durability of the Medtronic CoreValve System (MCS) (Medtronic, Minneapolis, Minnesota) at least 4 years post-TAVR.
Consecutive patients with at least 4 years of follow-up and single transfemoral MCS underwent transthoracic echocardiography (TTE) and MSCT after ethics committee approval (TACT, MEC-2013-331) and written informed consent were obtained. A pre-defined comparison was performed in patients with MSCT 5 to 6 months post-TAVR.
An expert echocardiographer performed and read the TTE studies according to the valve academic research consortium consensus document (4).
THV degeneration was defined as: 1) >10 mm Hg increase of mean transprosthetic gradient to a gradient ≥40 mm Hg; and/or 2) development of at least moderate aortic regurgitation (AR) that was less than moderate directly post-TAVR.
MSCT examinations (Definition, FLASH, or Force, Siemens Healthcare, Forchheim, Germany) were performed with electrocardiographic triggering or gated acquisitions in systole. Images were reconstructed and assessed (0.75 mm; Intellispace Portal, Philips, Best, the Netherlands) in end-systole by 2 experienced cardiovascular radiologists. Minimum/maximum diameter, area, and perimeter were defined at 3 pre-defined levels: inflow, nadir (of MCS leaflets), and outflow (central coaptation of MCS leaflets). Expansion (measured perimeter/nominal perimeter × 100%) and circularity (minimum diameter/maximum diameter × 100%) were derived. The presence of stent frame fractures and HALT was assessed. Longitudinal measurements (TTE, MSCT) were compared by paired Student t tests or Wilcoxon signed rank tests.
We included 20 (of 257) patients (age 80 years; interquartile range [IQR]: 73 to 83 years; logistic EuroSCORE 18%; 10% to 24%) with characteristics similar to those of excluded patients. Follow-up time for clinical events was 6 years (IQR: 4 to 8 years); 2 patients died after 8 years. Two transient ischemic attacks occurred (at 1 and 2 years), and no endocarditis or additional valve therapies.
TTE (median 5 years; IQR: 4 to 7 years) showed no changes in left ventricular ejection fraction, transprosthetic gradient, maximum velocity, velocity time integral ratio, effective orifice area, or AR over time (Figure 1). Two patients had MCS degeneration through deterioration of mild-to-moderate paravalvular leakage (PVL) (case 1) and moderate-to-severe valvular AR (case 2) after 6 years. PVL was stable in 10 and improved in 8 patients. Two patients developed mild valvular AR.
MSCT (median 5 years; IQR: 4 to 6 years) showed no frame fractures, whereas HALT was apparent in 50% without clinical consequence (Figure 1).
Eleven patients had undergone an earlier MSCT (median 5 months; IQR: 0 to 14 months post-TAVR). Over time, circularity extended from 82.4 ± 5.3% to 84.4 ± 5.4% (p = 0.019) and expansion from 83.3 ± 8.6% to 86.0 ± 7.2% (p = 0.005) at the inflow without differences in nadir and outflow. No relationship was observed between baseline calcification (Agatston score) and eccentricity or expansion over time. Four patients developed HALT early, which remained stable in 1, improved in 2, and deteriorated in 1 (case 1, with valve degeneration). Two patients developed HALT at late follow-up. Of note, no HALT occurred in case 2 who developed valve degeneration.
In summary, we observed preserved THV function and frame integrity at a median of 5 years post-TAVR. PVL typically remained stable or improved over time, although 1 patient had worse PVL and 1 patient had worse valvular AR. Transprosthetic gradients remained stable, which is consistent with findings from previous MCS studies (1). HALT was frequent (50%) at late follow-up without clinical consequence, in keeping with previous literature (3). Interestingly, our data suggest no interaction of oral anticoagulation therapy with late development of HALT, as the majority of patients with HALT were taking oral anticoagulants. We did not perform 4-dimensional scans and therefore cannot comment on leaflet mobility. We demonstrated for the first time continued MCS frame expansion and increased circularity between 5 months and 6 years post-TAVR at the inflow level. This may explain PVL improvement with self-expandable THV over time as suggested earlier (1). Further research is needed to understand HALT etiology (thrombotic vs. nonthrombotic) and to confirm our findings in larger populations because our observations stem from a limited pool of eligible patients.
Please note: Dr. de Jaegere is a consultant for Medtronic. Dr. Van Mieghem has received research grants from Medtronic, Abbott Vascular, Boston Scientific, and Claret Medical; and has received advisory fees from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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