Sensor-Guided Transcatheter Aortic Valve Replacement

Objectives. The SavvyWire(OpSens Medical) is a support wire for transcatheter aortic valve replacement (TAVR) procedures that, in addition to its dedicated left ventricle (LV) pacing capabilities, has a distal pressure sensor that measures live transvalvular hemodynamics during the procedure. We aimed to determine the safety, efficacy, and functionality of the SavvyWire during TAVR procedures in an all-comer population.

Methods. We performed a multicentric, prospective, observational, single-arm, all-comers registry of patients with symptomatic, severe aortic stenosis undergoing TAVR in 3 Canadian centers. Data were collected in a dedicated database, and pre-specified questionnaires were fulfilled by the heart team implanters after each procedure.

Results. A total of 60 patients were included (mean age: 78.6 ± 7.2 years; 51% women; mean Society of Thoracic Surgeons score: 2.2 ± 1.6%). TAVR was performed through a transfemoral approach in 90% of cases, and balloon- and self-expandable valves were used in 73% and 27% of patients, respectively. There were no cases of LV perforation, guidewire deformation, significant loss of capture, or major software malfunction. The rate of successful delivery of the TAVR system was 100%, and effective LV pacing was achieved in 98% of patients. The pre-TAVR mean gradient was 39 ± 14 mm Hg while the final post-TAVR gradient was 8 ± 5 mm Hg; the mean aortic systolic pressure during rapid pacing was 54 ± 12 mm Hg. In 97% of the TAVR procedures, SavvyWire's functionality was reported to be better or similar to other TAVR workhorse support wires.

Conclusions. SavvyWire was safe, effective, and functional for live transvalvular hemodynamic evaluation and rapid pacing during TAVR procedures. More studies with larger sample sizes and comparison against different wires and gradient measurement methods are warranted.

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Final transvalvular gradients following transcatheter aortic valve replacement (TAVR) were initially thought to have no impact on clinical outcomes.^1,2 However, recent evidence comparing post-TAVR echocardiographic and invasive hemodynamic evaluations showed a relationship between final transvalvular gradients and clinical outcomes, particularly in mortality.³

Discordance between echocardiography‐derived and directly measured mean gradients has been reported following TAVR and valve‐in‐valve TAVR.^4,5 This suggests that echocardiographic evaluation alone may not accurately reflect post-TAVR hemodynamics. Direct gradient measurement requires multiple catheter-wire exchanges, which may potentially increase the risk of complications;⁶ thus, a support guidewire with pressure measurement capabilities could more safely facilitate the TAVR hemodynamic evaluation.

The SavvyWire (Opsens Medical) is a 0.035-inch pre-shaped guidewire with a distal pressure sensor for continuous transvalvular hemodynamic monitoring and dedicated left ventricle (LV) pacing capabilities designed particularly for TAVR procedures.⁷ In an early feasibility study with the SavvyWire,⁷ the primary outcomes of effective rapid pacing runs and accurate pressure recordings were achieved, with no instances of pacing failure and with an adequate transcatheter heart valve (THV) deployment in all patients. Additionally, the SavvyWire was effective for backup pacing in the post-valve deployment period in cases of complete heart block, allowing a secure placement of a standard transvenous right ventricle (RV) temporary pacing lead under stable, paced conditions through the SavvyWire. Additionally, besides the gradient measurements, this wire provided multiple hemodynamic parameters that have been shown to improve TAVR procedural results and predict survival.⁸ However, data from the early feasibility study was preliminary, and the sample size was limited to only 20 patients. In addition, there is no information on the SavvyWire’s safety and efficacy in alternative access, complex anatomies, or valve-in-valve procedures. Thus, the objective of this study was to determine the safety and performance of the SavvyWire among all-comer patients with symptomatic severe aortic stenosis undergoing TAVR.

This was a multicentric, prospective, observational, single-arm, all-comers registry performed in 3 Canadian centers. The study was performed in accordance with the Ethics Committee of each participating center, and all patients provided signed informed consent for the procedures. Patients with symptomatic severe aortic stenosis with an indication for TAVR were included. All data were gathered in a dedicated database at each participant center, and pre-specified questionnaires were filled by the heart team implanters after each procedure.

SavvyWire. The SavvyWire is a stiff, 0.035-inch exchange length (280-cm long), pre-shaped wire dedicated to TAVR procedures. Its live pressure monitoring capabilities (Figure 1) are due to a fiber-optic sensor located in the distal segment before the pre-shaped distal tip. The proximal end of the wire is connected to the OptoMonitor 3 monitor (Opsens Medical) through a fiber-optic cable, which can be connected or disconnected anytime during the procedure. Its dedicated pacing capabilities (Figure 2) are due to conductivity of the core materials along with a PTFE (polytetrafluoroethylene) insulative sleeve with an insulative-free zone where a negative pacing alligator clamp is clamped and then connected to an external standard pacemaker source. Unipolar pacing is delivered by connecting the positive clamp to a needle in the patient's groin skin and setting the pacemaker source to max output (typically 25 mA).

Study outcomes. The primary safety outcome included the absence of major procedural complications related to the SavvyWire, including LV perforation, guidewire deformation, significant loss of capture during rapid pacing, and major software malfunction of the OptoMonitor 3. The primary efficacy outcomes were (1) successful delivery of TAVR system, (2) successful LV pacing capture, and (3) successful pressure display and recordings of the transvalvular gradient. Additionally, the wire handling (considering stiffness, support, and shape retention) was qualitatively evaluated by TAVR implanters and juxtaposed against prevailing commercial TAVR support wires (SAFARI2 [Boston Scientific], Confida Brecker [Medtronic], Lunderquist Extra-Stiff [Cook Medical] and Amplatz Super Stiff [Boston Scientific]).

Statistical analysis. The sample size was predefined in this post-market registry to include the first 60 patients undergoing a TAVR procedure with the SavvyWire following Health Canada approval. According to its normal distribution, categorical variables were reported as number (%), and continuous variables as mean ± standard deviation (SD) or median and interquartile range. Statistical analyses were performed with STATA 14 (StataCorp LLC).

From May 30, 2022, to August 26, 2022, 60 patients were included in this registry. Baseline characteristics are shown in Table 1. The mean age was 78.6 ± 7.2 years, and 51% were women. The mean left ventricle ejection fraction (LVEF) was 56.1 ± 10.1%, and the median Society of Thoracic Surgeons (STS) score was 2.2% (1.6%-3.8%). Among all patients, 4% (n = 2) displayed severe tortuosity in the main access vessel, 2% (n = 1) showed severe aortic tortuosity, and 22% (n = 13) had a horizontal aorta.

Procedural characteristics are summarized in Table 2. The distribution of THV types was 73% (n = 43) balloon-expandable (Sapien 3 Ultra [Edwards Lifesciences] in all cases) and 27% (n = 17) self-expandable (Evolut PRO [Medtronic]), with 10% (n = 6) of procedures being valve-in-valve and 5% (n = 3) in patients with native bicuspid aortic valve; 90% (n = 54) of the procedures were performed under conscious sedation. The transfemoral approach was used in 90% of cases. Of the alternative access cases, 2% (n = 1) were axillary and 8% (n = 5) transcarotid.

The primary safety and efficacy outcomes are summarized in Table 3. There were no cases of LV perforation, guidewire deformation, significant loss of capture, or major software malfunction. Effective LV rapid pacing using the SavvyWire was achieved in 98% (n = 59) of the cases. Pacing failure occurred in a young patient with cardiomyopathy, where rapid pacing proved challenging in decreasing systolic pressure. This was detected during the pacing test, so the physicians used a standard RV pacing wire for the THV implantation. Three patients (5%) presented with advanced atrioventricular block in the post-THV deployment phase, and all of them received prolonged LV pacing through the SavvyWire without loss of capture.

The rate of successful delivery of the TAVR system was 100% (n = 60), and the rate of successful display of pressure and gradients by the OptoMonitor 3 was 95% (n = 57). All minor display errors were subsequently fixed in software updates. The pre- and post-TAVR mean gradients were 39 ± 14 mm Hg and 8 ± 5 mm Hg, respectively, and the achieved aortic systolic pressure during rapid pacing was 54 ± 12 mm Hg. The summary of pre- and post-TAVR hemodynamic measurements is shown in Table 4.

Overall, 68% of physicians reported that the SAFARI2 wire was their workhorse support wire for TAVR procedures, followed by the Confida Brecker (22%) and Amplatz Super Stiff (7%) wires. In 97% of the TAVR procedures, the SavvyWire was reported to be better or similar to other TAVR workhorse support wires (Figure 3).

In this first real-life, all-comers registry of patients with symptomatic severe aortic stenosis undergoing TAVR, the use of the SavvyWire proved to be (1) safe, with no incidences of cardiac or wire damage,  significant loss of capture, or software malfunction; (2) effective, with 100% success rate of THVs system's delivery, and optimal reduction of the systolic aortic pressure during rapid in the vast majority of patients;  and (3) functional, since it was qualified as similar or superior to conventional TAVR workhorse wires according to most of the TAVR implanters involved in this study.

The SavvyWire was safe when used as a TAVR exchange and support wire, as shown by the absence of wire-related cardiac complications and wire damage. From the side of pacing capabilities safety, the rate of significant loss of capture was 0%, with no cases of valve embolization or any significant structural or hemodynamic consequence. The safety profile appeared to be better when compared to the rate of right-ventricle-associated cardiac tamponade, which has been reported in up to 2% of patients undergoing TAVR.⁹ Additionally, in patients undergoing TAVR, it is known that LV rapid pacing is as effective as RV pacing, but it is associated with lower rates of tamponade compared with RV pacing.¹⁰ Furthermore, our findings aligned with the initial preliminary results of the SavvyWire, underscoring the device's safety.

The efficacy of the SavvyWire for delivering THV systems was 100%, which translates into a very effective TAVR support wire. Its effectiveness for LV rapid pacing was near 100%, with one particular case deemed by the TAVR implanter to be best performed under RV pacing since, in the pace testing phase of the SavvyWire, difficulties were observed in the desired goal of blood pressure drop; however, this was mainly related to the patient’s baseline conditions. Thus, according to the implanter's criteria, the SavvyWire was not used as a precautionary measure for the final THV implantation.

The OptoMonitor 3 presented a low rate of minor display issues, all of which were addressed in subsequent software updates, allowing a final successful display of pressure and gradients of 95%. Additionally, the OptoMonitor 3 provides real-time additional important hemodynamic parameters, such as the aortic regurgitation index (ARi) that independently predicts 1-year mortality in patients undergoing TAVR.¹¹

Overall, the use of the SavvyWire showed the same efficacy profile as in the early feasibility study, where the authors achieved a 100% success rate but in a very small sample size of selected patients.⁷ Our results showed the efficacy of the SavvyWire also in patients with challenging anatomical situations like severe iliofemoral tortuosity or horizontal aorta, as well as in valve-in-valve and bicuspid aortic stenosis cases. Thus, these results suggest that this wire could be used in the vast majority of real-world TAVR cases.

The functional evaluation of the SavvyWire handling was qualified as better than or similar to conventional TAVR workhorse wires according to the vast majority of the TAVR implanters when considering several factors such as stiffness, support, and shape retention. This is important in demonstrating that the added dedicated pacing and hemodynamic monitoring capabilities did not compromise the physical handling of the guidewire. LV-pacing through the TAVR delivery system wire is not a novel technique;¹² however, SavvyWire is currently the only support wire designed for this purpose, which, enhanced with its sensor-guided TAVR capabilities, seems to be an add-on that optimizes TAVR procedures.

Study limitations. Although this was a multicentric prospective study with a larger sample size than the first early feasibility study, our sample size remains a limiting factor for interpreting our results and conclusions. Larger studies comparing rapid LV pacing against other support wires or RV pacing could provide more information regarding the efficacy and safety of using the SavvyWire. The OptoMonitor 3 exhibited minor errors, all of which have been addressed and are expected to enhance the device's performance in future uses. Functionality assessment was qualitatively based on physicians' appreciation considering stiffness, support, and shape retention, and no specific tests or measurements were performed. Most importantly, although a complex relationship has been shown between final post-TAVR gradients and outcomes, we only presented post-procedural results; thus, long-term data on the impact of sensor-guided TAVR on clinical outcomes are warranted.

In this prospective series of all-comer patients with severe aortic stenosis undergoing TAVR, the use of SavvyWire was found to be safe since no major complications were observed; it was also found to be effective, achieving an adequate blood pressure drop in 98% of patients and 100% of LV capture. Additionally, most of the TAVR implanters rated the wire's functionality as either superior to or similar to conventional support wires. Although additional studies on invasively measured gradients with the SavvyWireand its impact on clinical outcomes are warranted, currently, its use seems to be an add-on that optimizes TAVR procedures.

From the ¹Quebec Heart and Lung Institute, Quebec, Canada; ²Montreal Heart Institute, Montreal, Canada; ³Vancouver General Hospital, Vancouver, Canada.

Acknowledgments: The authors would like to thank Emilie Pelletier-Beaumont, MSc, and Siddhartha Mengi, MD, from the Quebec Heart and Lung Institute, Quebec City, Canada, for their help in the preparation of this manuscript. Dr. Rodés-Cabau holds the Research Chair “Fondation Famille Jacques Larivière” for the Development of Structural Heart Disease Interventions (Laval University, Quebec City, Canada).

Disclosures: Dr Ibrahim is a consultant and has received speaker fees from Opsens Medical. Dr Sathananthan has served as a consultant for Edwards Lifesciences and Medtronic and received research funding from Edwards Lifesciences and Medtronic. Dr Rodés-Cabau has received institutional research grants from Opsens Medical, Edwards Lifesciences, and Medtronic, consulting fees from Medtronic, and speaker fees from Edwards Lifesciences and Medtronic. The remaining authors report no financial relationships or conflicts of interest regarding the content herein.

Funding: This study was supported by Opsens Medical, Quebec City, Canada.

Address for correspondence: Josep Rodés-Cabau, MD, PhD, Quebec Heart & Lung Institute, Laval University; 2725 Chemin Ste-Foy, G1V 4G5, Quebec City, Quebec, Canada. Email: josep.rodes@criucpq.ulaval.ca.