In the era of expanding transcatheter aortic valve implantation (TAVI) indications for low surgical risk patients, conduction disturbances requiring permanent pacemaker implantation (PPI) after TAVI remain a serious concern. We aimed to assess the impact of the radiolucent line-guided technique for the SAPIEN 3 implantation on reducing the rates of new-onset PPI after TAVI. A total of 326 patients treated with the SAPIEN 3 using either the radiolucent line-guided technique (lucent group, 170 patients [52.1%]) or the center marker-guided technique (conventional group, 156 patients [47.9%]) were prospectively included in our database. The prosthesis position, and 30-day and 3-year clinical outcomes were retrospectively assessed. Compared with the conventional group, the lucent group had a higher prosthesis position (1.7 ± 0.9 mm vs 4.2±1.5 mm, p <0.001) and lower 30-day PPI rates (2.9% vs 13.5%, p <0.001). The other periprocedural complications including valve dislodgement and coronary obstruction, and 30-day and 3-year mortality were comparable between the groups. However, the prosthesis frame extending above sinotubular junction was more frequently observed in the lucent group on the side of left coronary sinus (53.4% vs 31.4%, p <0.001) and right coronary sinus (35.0% vs 20.2%, p = 0.001), signifying a potential risk for “subsequent difficulties to access coronary ostia” and “coronary obstruction during future redo TAVI.” In conclusion, the radiolucent line-guided technique predictably provided an extremely high position of the SAPIEN 3, reducing the postprocedural PPI rates compared with the center marker-guided technique.
Transcatheter aortic valve implantation (TAVI) was established as a therapeutic alternative to surgical aortic valve replacement for inoperable or high-risk patients with severe aortic stenosis. , Recently, indications for TAVI have been expanded to include lower-risk patients; however, conduction disturbances requiring permanent pacemaker implantation (PPI) after TAVI remain a serious concern. Mechanical compression of the conduction tissue located at the membranous septum was reported to be a leading cause of conduction impairment, , and the prosthesis depth was identified as a powerful predictor of PPI. Taking these results, a central balloon marker-guided SAPIEN 3 (Edwards Lifesciences, Irvine, California) implantation providing a higher prosthesis position (a ventricular portion of <30%) has been utilized; however, PPI rates remain relatively high (>9%). We therefore utilized the radiolucent line located at the superior aspect of the lowest set of stent struts of the crimped SAPIEN 3 to achieve a quite high implantation. The aim of our study was to assess the impact of the radiolucent line-guided implantation on the rates of postprocedural PPI.
Methods
All 349 consecutive patients with symptomatic severe aortic stenosis treated with the SAPIEN 3 at our institute between May 2016 and March 2019 were prospectively included in our TAVI database. Among those, we excluded 19 patients with previous cardiac electronic device, 3 patients with bicuspid aortic valve, and 1 patient with previous bioprosthesis from analysis to assess the new-onset PPI rates after TAVI ( Figure 1 ). Indications for TAVI were discussed by members of a dedicated heart team, based on not only surgical risk scores, but multiple factors including age, frailty, and preoperative state for the noncardiac surgery. The prosthesis size and inflation volume of the deployment balloon were determined on the basis of the annulus size and the other anatomic characteristics, including aortic-valvular complex calcification. The devices were delivered through the transfemoral, transiliac, or transapical approach. The coplanar angle was angiographically modified during the procedure based on a preprocedural multidetector computed tomography (MDCT). Prosthesis implantations were performed using either the conventional center marker-guided implantation or the radiolucent line-guided implantation introduced in January 2018. The cases in which the radiolucent line-guided implantation was performed were prospectively recorded. The conventional center marker-guided implantation indicated the alignment of the center marker on the deployment balloon just above the bottom of the right coronary cusp with the projection from a pigtail catheter in the right coronary cusp, and the radiolucent line-guided implantation indicated the alignment of the top of the radiolucent line of the crimped prosthesis with the bottom of the noncoronary cusp (NCC) with the projection from a pigtail catheter in the NCC ( Figure 2 ). After the crimped prosthesis straddled the annulus, we released the flex in the delivery system before the prosthesis implantation for both techniques. When the radiolucent line was not clearly visualized, we moved the x-ray tube more caudally from the coplanar angle until a precisely orthogonal image of the prosthesis was obtained to help get rid of the parallax in the prosthesis. For both implantation techniques, postdilatation was actively performed as deemed necessary by the operator to mitigate not only the paravalvular leakage but also the recoil of implanted prosthesis. Postdeployment aortic angiograms were performed for all patients to assess the prosthesis position and paravalvular leakage.
The primary outcome measure of the study was PPI within 30 days after the TAVI procedure. The decision to perform PPI was based on the presence of an advanced second-degree atrioventricular block (AVB) ≥7 days or complete AVB ≥3 days with the agreement about the need for PPI in our electrophysiology team. The secondary outcome measures included new-onset left bundle branch block, procedural complications, and the 30-day and 3-year mortality. Procedural outcomes were assessed according to the Valve Academic Research Consortium 2 consensus. Information on the occurrence of adverse events after discharge were obtained from follow-up outpatient visits or telephone interviews conducted at the 30th day, the sixth month, and then yearly. The local institutional review board approved this study protocol, and a written informed consent was obtained from all patients before the TAVI procedure.
All patients underwent preprocedural electrocardiographically gated MDCT using a 256-row system (Revolution CT, GE Healthcare, Waukesha, Wisconsin) with a slice thickness of 0.625 mm and 25 to 70 ml of intravenously administered contrast agent (Oypalomin 350, Fuji Pharma, Tokyo, Japan). Off-line measurements were performed with 3mensio Valves software version 7.0 or 8.0 (Pie Medical Imaging, Maastricht, The Netherlands). The aortic annulus and left ventricular outflow tract area were measured in mid-systole. Calcium quantification of leaflet was made using the J-score from contrast scans (850 Hounsfield unit threshold of detection). The membranous septum length was measured as the distance of the intraventricular septum from the bottom of NCC to the top of the muscular septum on standard coronal view. The percentage of prosthesis oversizing by area compared with the annulus area was calculated using the formula: (nominal prosthesis area ÷ computed tomography annulus area – 1) × 100.
Postprocedural electrocardiographically gated MDCT was performed to assess the positional relation of the implanted prosthesis and the surrounding structures, unless renal function precluded contrast administration. As previously reported, in patients with the prosthesis stent frame above sinotubular junction (STJ), we defined the presence of a commissural suture post within 15° of rotation on either side of a coronary ostium as “the challenging anatomy for coronary access,” and the distance between the prosthesis frame and the STJ <2.0 mm as “the risk of coronary obstruction in future redo TAVI” , ( Figure 3 ).
Prosthesis implantation depth was measured from off-line evaluation of postdeployment aortic angiograms with the angles adjusted to obtain an orthogonal view of the prosthesis stent frame. Implantation depth was defined as the distance from the bottom of the NCC to the most proximal edge of the stent frame. The quantitative measurements were assessed using a dedicated software (QAngio version 7.3, Medis, Leiden, The Netherlands). Calibration was performed using a 5 Fr pigtail catheter (Terumo Corp., Tokyo, Japan). Implantation depths were evaluated by 2 independent cardiologists who were blinded to clinical information. To evaluate intra- and interobserver variabilities, we randomly selected a repeated measurement for a subset of 20 patients. Intra- and interobserver agreements were almost perfect (intraobserver:intraclass correlation coefficient 0.97; interobserver: intraclass correlation coefficient 0.96).
All statistical analyses were performed using JMP 14 (SAS Institute Inc., Cary, North Carolina) and R version 4.0.2 (R Foundation for Statistical Computing, Vienna, Austria). Categoric variables were described as number and percentage and compared using the Fisher’s exact test. Continuous variables were described as mean ± SD or median (interquartile range [IQR]) and were compared using t test or Wilcoxon rank-sum test based on their distributions. Cumulative event rates were analyzed using the Kaplan–Meier estimation, and differences were assessed with the log-rank test. For the post hoc analyses, we dichotomized patients based on (1) median age of 85 years, (2) gender, (3) preprocedural complete right bundle branch block (CRBBB), (4) median membranous septum length of 4.5 mm, and (5) median valve calcium volume of 218.5 mm 3 . Two-sided p <0.05 were considered statistically significant.
Results
Of the 326 patients eligible for analysis, 170 patients (52.1%) underwent radiolucent line-guided implantation (lucent group) and 156 patients (47.9%) underwent conventional center marker-guided implantation (conventional group). Baseline clinical characteristics are presented in Table 1 . The mean age was 84 years, 33% of patients were men, and the median Society of Thoracic Surgeons Predicted Risk of Mortality was 5.2%. The patient demographics were comparable between the 2 groups except for the prevalence of liver disease (0.6% vs 4.5%, p = 0.030). No significant group differences were observed in baseline electrocardiographic and echocardiographic data. The membranous septum was also similar between the 2 groups (4.4 ± 1.6 mm vs 4.6 ± 1.7 mm, p = 0.41). The procedural characteristics are listed in Table 2 . Almost all patients (94.8%) underwent TAVI by way of the transfemoral approach. TAVI was performed using 20-, 23-, 26-, and 29-mm SAPIEN 3 prostheses in 5 (1.5%), 159 (48.8%), 126 (38.7%), and 36 patients (11.0%), respectively. The degree of oversizing and the rates of predilatation and postdilatation were also comparable between the 2 groups.
| Variable | Lucent group (n = 170) | Conventional group (n = 156) | P value |
|---|---|---|---|
| Age (years) | 84.4 ± 4.8 | 84.3 ± 5.6 | 0.84 |
| Male | 60 (35.3%) | 48 (30.8%) | 0.41 |
| Body mass index (kg/m 2 ) | 22.5 ± 3.6 | 22.5 ± 3.9 | 0.90 |
| Clinical frailty scale ≥ 5 | 29 (17.1%) | 28 (18.0%) | 0.88 |
| Hypertension | 133 (78.2%) | 117 (75.0%) | 0.51 |
| Dyslipidemia | 76 (44.7%) | 69 (44.2%) | 1.00 |
| Diabetes mellitus | 38 (22.4%) | 33 (21.2%) | 0.89 |
| Chronic kidney disease = eGFR < 60 ml/min/1.73 m 2 | 111 (65.3%) | 111 (71.2%) | 0.29 |
| Atrial fibrillation | 31 (18.4%) | 31 (19.9%) | 0.78 |
| Coronary artery disease | 63 (37.1%) | 56 (35.9%) | 0.91 |
| Previous myocardial infarction | 14 (8.2%) | 12 (7.7%) | 1.00 |
| Previous coronary bypass | 3 (1.8%) | 6 (3.9%) | 0.32 |
| Previous valve surgery | 1 (0.6%) | 0 (0.0%) | 1.00 |
| Peripheral artery disease | 14 (8.2%) | 10 (6.4%) | 0.67 |
| Chronic obstructive pulmonary disease | 13 (7.7%) | 20 (12.8%) | 0.14 |
| Cerebrovascular disease | 18 (10.6%) | 19 (12.2%) | 0.73 |
| NYHA functional class Ⅲ/Ⅳ | 63 (37.1%) | 56 (35.9%) | 0.91 |
| Liver disease | 1 (0.6%) | 7 (4.5%) | 0.03 |
| STS-PROM score (%) | 5.0 (3.8-8.2) | 5.3 (3.8-8.2) | 0.39 |
| Beta-blocker therapy | 55 (32.4%) | 61 (39.1%) | 0.25 |
| Electrocardiographic data | |||
| PQ interval (ms) (n = 280) * | 176 (160-205) | 180 (161-214) | 0.17 |
| First-degree AVB (n = 280) * | 46/147 (31.3%) | 48/133 (36.1%) | 0.45 |
| QRS duration (ms) | 92 (86-102) | 93 (86-104) | 0.20 |
| LBBB | 6 (3.5%) | 6 (3.9%) | 1.00 |
| Incomplete RBBB | 4 (2.4%) | 2 (1.3%) | 0.69 |
| Complete RBBB | 19 (11.2%) | 22 (13.5%) | 0.61 |
| Echocardiographic data | |||
| Aortic valve area (cm 2 ) | 0.69 ± 0.17 | 0.66 ± 0.13 | 0.09 |
| Indexed aortic valve area (cm 2/ m 2 ) | 0.48 ± 0.12 | 0.47 ± 0.11 | 0.39 |
| Aortic valve mean gradient (mmHg) | 45.6 ± 17.5 | 46.3 ± 16.4 | 0.73 |
| Left ventricular ejection fraction (%) | 58.7 ± 9.8 | 58.6 ± 9.5 | 0.91 |
| Left ventricular end-diastolic diameter (mm) | 44.3 ± 6.2 | 44.7 ± 5.7 | 0.77 |
| Aortic regurgitation ≥ moderate | 7 (4.1%) | 9 (5.8%) | 0.61 |
| Mitral regurgitation ≥ moderate | 4 (2.4%) | 5 (3.2%) | 0.74 |
| Tricuspid regurgitation ≥ moderate | 3 (1.8%) | 6 (3.9%) | 0.32 |
| Systolic pulmonary arterial pressure (mmHg) | 32.2 ± 8.2 | 33.8 ± 10.2 | 0.13 |
| MDCT data | |||
| Annulus area (mm 2 ) | 419.3 ± 69.2 | 418.5 ± 78.3 | 0.92 |
| Annulus perimeter (mm) | 73.1 ± 5.8 | 73.0 ± 6.5 | 0.83 |
| LVOT area (mm 2 ) | 418.6 ± 91.5 | 412.5 ± 105.7 | 0.58 |
| STJ height (mm) | 18.8 ± 2.7 | 18.9 ± 2.8 | 0.74 |
| STJ diameter (mm) | 25.0 ± 3.0 | 25.3 ± 3.1 | 0.37 |
| Left coronary artery height (mm) | 13.3 ± 2.0 | 13.4 ± 2.0 | 0.57 |
| Right coronary artery height (mm) | 15.3 ± 3.1 | 14.9 ± 2.6 | 0.16 |
| Membranous septum length (mm) | 4.4 ± 1.7 | 4.6 ± 1.7 | 0.41 |
| 850-HU valve calcium volume | |||
| Total (mm 3 ) | 215.0 (102.3-344.3) | 220.6 (105.1-358.2) | 0.85 |
| Non-coronary cusp (mm 3 ) | 106.2 (44.6-194.0) | 112.4 (46.2-208.1) | 0.54 |
| Right coronary cusp (mm 3 ) | 46.4 (20.1-93.2) | 42.1 (13.6-80.4) | 0.68 |
| Left coronary cusp (mm 3 ) | 36.1 (15.2-86.6) | 42.6 (10.1-95.9) | 0.87 |
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