Transcatheter Aortic Valve Implantation: All Transfemoral? Update on Peripheral Vascular Access and Closure

Transfemoral access remains the most widely used peripheral vascular approach for transcatheter aortic valve implantation (TAVI). Despite technical improvement and reduction in delivery sheath diameters of all TAVI platforms, 10–20% of patients remain not eligible to transfemoral TAVI due to peripheral artery disease. In this review, we aim at presenting an update of recent data concerning transfemoral access and percutaneous closure devices. Moreover, we will review peripheral non-transfemoral alternative as well as caval-aortic accesses and discuss the important features to assess with pre-procedural imaging modalities before TAVI.

Initial experience, feasibility and safety of permanent left bundle branch pacing; a retrospective single centre study

Funding Acknowledgements Type of funding sources: None. Background Physiologic pacing by left bundle branch pacing (LBBP) is characterized by direct stimulation of the intrinsic His-Purkinje system and results in physiologic ventricular depolarization and repolarization. This technique has emerged as an alternative to both traditional right ventricular pacing for bradycardia and classic cardiac resynchronization therapy (CRT). High success rates and low complication rates are reported, however the majority of literature is reported by relatively few, highly experienced centres. Purpose This retrospective study aims to describe success rate, feasibility and safety of LBBP for both bradycardia and CRT indications in a high volume referral centre, performed by three physicians without previous experience with LBBP. Methods 100 patients who underwent attempted LBBP from January 2020 to September 2020 were analysed. LBBP was performed using the Medtronic SelectSecure 3830 pacing lead and the Medtronic C315HIS delivery sheath. The primary end points are acute LBBP success rates and LBBP related complications within 3-6 months from implantation. Success was defined as a paced QRS with QR or RSr’ in V1 and left ventricular activation time (LVAT) <90ms. Device follow-up data was acquired at 1 month and 3-6 months after implantation. Results The mean age was 70 ± 11.4 years and 67% were men. 57% had a left ventricular ejection fraction <0.50 and QRS was 146 ± 33.7ms. Pacing indication was CRT in 48, bradycardia in 42 and planned AV node ablation in 9. LBBP was successful in 83/100 patients (83%), with paced QRS of 121 ± 19.7ms and LVAT of 81 ± 13.8ms. A learning curve could not be demonstrated; the success rates in the first and latter half were 78% and 88% respectively (p = 0.183). Pacing parameters at implantation were satisfactory; R-wave 11.9 ± 5.9mV, impedance 736 ± 153Ω and capture threshold 0.7 ± 0.4V. R-wave increased to 14.6 ± 6.3mV at 1 month (p < 0.001) and remained stable at 13.6 ± 5.5mV after 3-6 months (p = 0.829). Impedance decreased to 572 ± 82Ω at 1 month (p < 0.001) and further decreased to 536 ± 81Ω after 3-6 months (p < 0.001). Capture threshold remained stable at 1 and 3-6 months (0.7 ± 0.2V (p = 0.287) and 0.8 ± 0.2V (p = 0.055), respectively). No LBBP related complications, e.g. lead perforation or dislodgement, occurred during the follow-up of 249 ± 64 days. The main reasons for unsuccessful implantation (n = 17) were insufficient reach of the delivery sheath (n = 8) and inability to penetrate the septum due to fibrosis (n = 5). Conclusion This study shows that LBBP is a safe and feasible method for delivering physiological pacing. Without previous experience, our initial success rate is comparable to highly experienced centres. Pacing parameters remained stable after 6 months and no LBBP complications occurred. Success rate of implantation could further improve with dedicated LBBP delivery sheaths. Large randomized controlled trials are needed to further confirm safety and efficacy of LBBP.

Success and failure for implantation of left bundle branch pacing using stylet-driven pacing leads : a single center experience

Funding Acknowledgements Type of funding sources: None. Background/Introduction :Left bundle area pacing is a new modality of physiological pacing. By screwing the pacing lead deep into the interventricular septum, the left bundle branch could be recruited for pacing purpose. Initially left bundle area pacing was performed with fixed helix lead supported by the delivery catheter. On the other hand, there are studies showing the feasibility of using a style-driven extendable helix with the new delivery sheath for left bundle area pacing. Purpose :To study the feasibility of left bundle area pacing and explore factors associated with success and failure Methods :This is a retrospective study from September 2020 to January 2021 in a local hospital. Baseline patient characters, procedural characters, acute complication and reason for failure were recorded. Logistic regression was done to explore factors associated with success and failure. Results :In 14 patients, the mean age is 81 +/- 6.8 years with 28% female. Pacing indications were sick sinus syndrome (n = 3) and atrio-ventricular block (n = 11). The success rate is 64% (n = 9/14). The average R wave sensing was 11.4 +/- 4.5mV, the average V pacing threshold was 0.88 +/- 0.23V @ 0.4ms and average impedance was 633 +/- 93.6 Ohm. There were no septal perforation nor pericardial effusion after implantation. The most common reason for failure is lead dislodgement during implantation (n = 4) and the other reason is failure to locate and capture the left bundle (n = 1). In logistic regression, there was no clinical risk factor identified to predict failure for implantation , i.e. diabetics ( OR 0.95, p =0.15), hyperlipidaemia (OR 0.87, p =0.94), chronic renal disease (OR 0.88, p = 0.94), coronary heart disease (OR 0.37, p = 0.66). Gender(OR 4.5, p = 0.37), age(OR 1.1, p = 0.32) and hypertension(OR 25, p = 0.25) may appear to predict failure for implantation but the results were not statistically significant. Conclusion :Left bundle area pacing could be feasible and safely implanted using style-driven lead with good pacing parameters. No clinical factor is identified to predict the failure of implantation, the main reason for failure is dislodgement of lead during implantation. Similar finding was noted in a study comparing lumen-less lead and stylet-driven lead.2 In this study found that reason for failure of left bundle area pacing using style-driven lead was due to repetitive lead dislodgement after slitting the delivery sheath, fail advancement of lead into septum and loose septal endocardium. Stability and ability to screw into septum remain a great obstacle for left bundle area pacing using stylet-driven lead. This study is limited by small sampling size and single center retrospective study. Further studies are needed to see the long term outcome of left bundle area pacing using style-driven lead and investigate other methods to predict success/ failure of implantation, such as the role of imaging.

Cobra-head and other shape-memory abnormalities of nitinol atrial septal occluders: incidence, predisposing factors, and outcomes

Background: Shape-memory abnormalities are seen in some nitinol atrial septal occluders. Variably described as cobra-head, tulip, and others, their incidence, mechanisms, clinical impact, and outcome have not been systematically analysed. Methods: We retrospectively reviewed all consecutive device closures in the last 6 years for deformations. Type and size of the occluder, deployment technique, size, and angulation/kinking of the delivery sheath were analysed. Procedural success, duration, and other complications were studied. Results: A total of 112 devices (11.8%) among 950 occluders used in 936 patients showed deformities. Fourteen of 936 received 2 devices. Deformities were transient and self-correcting in 40%. Multivariate analysis showed significant associations with oversized sheaths (p = 0.004), kinked/angulated sheaths (p < 0.001), special deployment techniques (p < 0.001), and twist in the device waist (p = 0.011). Despite more frequent deformities with Figulla (15.6%) and Amplatzer (13.9%) occluders than Cera occluders (6.6%) and larger devices (>24 mm – 14.6%) than smaller devices (less than or equal to 24 mm – 9.7%), they were not significant on multivariate analysis. In vivo manipulations corrected most deformities; nineteen needed in vitro reformations and four needed a change of device. Despite prolongation of the procedure, repeated attempts (mean 2.76 ± 1.7 attempts, with a range from 1 to 9 attempts), and supraventricular tachycardia in two patients, there were no serious adverse effects. Conclusions: Deformations were frequent in 11.8% of atrial septal occluders on a targeted search. Oversized and angulated/kinked sheaths, special techniques like pulmonary vein deployment and twist in device waist during procedure predisposed to deformities. While most deformities were corrected with manipulations, removal of the device was infrequently needed and change of device was rarely required. Long procedural time and multiple attempts for deployment did not affect procedural success.