Improved Transseptal Access for Transcatheter Paravalvular Leak Closure Using Steerable Delivery Sheaths: Data From a Prospective Registry

Abstract: Background. Transcatheter closure of mitral paravalvular leaks (PVLs) can be a lengthy and cumbersome procedure that may not guarantee satisfying results. We used steerable sheaths in order to perform these procedures in a faster and more controllable manner. Methods. FlexCath and Occlutech steerable sheaths were used. After transseptal puncture, the sheath was introduced into the left atrium and positioned co-axially above the PVL channel. A 5 Fr Judkins catheter was used to cross the PVL channel. A distance wire was placed in most cases through the sheath in the left atrium. A delivery set with a closure device was introduced. The device was positioned under echocardiographic and fluoroscopic guidance and deployed. Technical success rate (TSR) and implantation time (IT) were compared with a control group of mitral PVLs closed without a steerable sheath. Results. TSR was higher for the steerable sheath group (93.5% vs 72.7%; P<.05). There were no adverse events during index hospitalization. Median IT was shorter for cases performed with steerable sheaths vs cases performed without a steerable sheath (28.5 min [range, 15–58 min] vs 64 min [range, 35-180 min], respectively; P<.05). Conclusions. Steerable sheaths are safe and effective devices that support mitral PVL closure, particularly in cases with challenging PVL locations.

J INVASIVE CARDIOL 2019;31(8):223-228. Epub 2019 April 15.

Key words: mitral valve leak, paravalvular leak, prosthetic valve

Paravalvular leak (PVL) has been defined as the presence of an abnormal communication between heart chambers adjacent to a prosthetic valve. Mitral PVLs are more common than aortic and it has been estimated that they may be present in various levels of severity in up to 17% of patients after mitral valve replacement (MVR).¹ Many PVLs require no further treatment. However 1%-3% of patients with PVL ultimately develop symptoms of heart failure or hemolytic anemia that warrant intervention.^2,3

Mitral PVL closure is a very demanding procedure. Despite the introduction of some dedicated devices, we lack a specific system that could guarantee foreseeable results. Many techniques, including antegrade, retrograde and transapical approaches, are utilized.⁴ Typically, various wires are used to cross the PVL and then a diagnostic catheter is advanced over the wire. However, regardless of the approach, the operator is frequently faced with various difficulties. Mitral PVLs can be located all around the annulus, and getting to the right spot can be problematic. PVL channels can be heavily calcified and serpiginous; therefore, it can be troublesome to cross the PVL channel with a delivery set. Lack of coaxial alignment between the delivery sheath and the PVL channel can result in skewed implantation angle, because retraction of the delivery sheath after the ventricular disc of a device is opened can dislocate the device.

To overcome the above-mentioned difficulties, we decided to use a large and steerable sheath that could be firmly placed above the PVL channel to serve as a “guiding port” for further steps of the procedure. Due to a lack of dedicated equipment that would serve the stated purpose, we chose two commercially available sheaths that are used in different interventional procedures:  (1) the FlexCath steerable sheath (Medtronic); and (2) the Occlutech steerable guiding sheath (Occlutech). The FlexCath sheath is a unidirectional, deflectable sheath typically used for positioning of cryoablation catheters. The sheath has an inner diameter of 12 Fr and can accommodate catheters up to 10.5 Fr. The Occlutech sheath is a deflectable sheath used for left atrial appendage closure. It can perform deflection up to 180° and comes in two sizes, with an inner diameter of 12 Fr or 14 Fr. Our idea was to use these sheaths in a manner similar to the steerable guide catheter used for MitraClip implantation (St. Jude Medical) in order to achieve greater stability and maneuverability.

Methods

This study was designed as a prospective registry of 31 consecutive patients with a mitral PVL. Inclusion criteria were: (1) age >18 years old; (2) PVL around a mitral prosthesis (mechanical or biological); (3) presence of clinical (heart failure or hemolysis) and echocardiographic criteria of PVL severity; and (4) initial echocardiographic evaluation indicating that the PVL could be closed with a device of an appropriate size. Exclusion criteria were: (1) rocking of the prosthesis; (2) large or multiple PVLs that could not be closed percutaneously; or (3) signs of active infection.

Patient demographics and medical history are depicted in Table 1. The sizes of all leaks were evaluated prior to the procedure with real-time three-dimensional transesophageal echocardiography (RT-3D-TEE), and all measurements were repeated during the procedure (Figure 1). The locations of the leaks were reported from surgical perspectives in the following manner: anterior (hours 10-1); medial (hours 1-4); posterior (hours 4-7); and lateral (hours 7-10).

All procedures were performed under conscious sedation with sedatives administered as per unit protocol (fentanyl and diazepam intravenously) under RT-3D-TEE and fluoroscopic guidance. After obtaining vein access via the right femoral vein, transseptal puncture was performed and a Swartz transseptal guiding introducer sheath (St. Jude Medical) was placed in the left atrium. Heparin was administered to achieve activated clotting time >300 seconds. Next, the sheath was exchanged over a stiff wire (Amplatz Super Stiff guidewire; Boston Scientific) for either the FlexCath sheath (Figure 2) or the Occlutech sheath (Figure 3), which were positioned above the PVL channel. A 5 Fr Judkins right guide catheter (Medtronic) or a telescopic system made of a 6 Fr guide catheter and a 5 Fr diagnostic catheter was then introduced through the sheath and used to cross the PVL (Figure 4). Next, in most cases, two wires were placed in the left ventricle – a safety wire and a regular 0.035˝ J-type wire (Figure 5). In addition, a V-18 ControlWire (Boston Scientific) or a regular BMW wire (Abbott) was passed through the sheath and placed in the left atrium to keep an appropriate distance between the sheath and the PVL channel (Figure 6). A delivery sheath was introduced into the left ventricle over the wire placed in the PVL channel, followed by advancement of the appropriate closure device(s) (Figures 7 and 8). Device(s) were properly rotated prior to deployment. TEE was used to confirm whether deployment of device(s) led to significant reduction in the PVL size and did not interfere with motion of the prosthesis. Next, a tug test was performed to assess stability, and finally, device(s) were detached from the delivery set (Figure 9). After removal of the sheath, vein access was closed with a z-suture.

The control group comprised mitral PVL closure procedures that were done in our center prior to introduction of the steerable sheath. All procedures in the control group were performed in an antegrade manner via a transseptal puncture. To cross the PVL, a telescopic system comprised of a 6 Fr Judkins right or multipurpose catheter with a diagnostic catheter was used. To reach every possible location around the mitral annulus, this approach often required formation of an intra-atrial loop with the above-mentioned telescopic system.

Due to the potential benefits of the steerable sheath throughout all stages of the procedure that could shorten procedural time, we defined implantation time (IT) as time from transseptal puncture to release of the device(s). Technical success rate (TSR) was defined as suggested in an expert statement from the Paravalvular Leak Academic Research Consortium (PLARC)⁶ and included the following components: (1) absence of procedural mortality or stroke; (2) successful access, delivery, and retrieval of the device delivery system; (3) proper placement and positioning of device(s); (4) freedom from unplanned surgical or interventional procedures related to the device or access procedure; (5) no evidence of structural or functional failure of the prosthetic valve; (6) no specific device-related technical failure issues and complications; and (7) reduction of regurgitation to no greater than mild (1+) paravalvular regurgitation.  We compared technical success rate (TSR) and implantation time (IT) between the steerable sheath group and the control group.

Statistical analysis. Statistical analysis was performed with MedCalc Statistical Software version 14.12.0 (MedCalc Software bvba). Categorical variables are presented as number (percentage). Continuous variables are expressed as mean ± standard deviation or median (range) depending on the distribution of variables. The Shapiro-Wilk test was used to check for normal distribution of variables. The Mann-Whitney test was used for non-normally distributed continuous variables and results are reported as median (range). Categorical variables were compared with Fisher’s exact test. A P-value <.05 was considered statistically significant.

Results

Technical and procedural characteristics are depicted in Table 2. There were no statistically significant differences regarding PVL sizes and locations between the two groups. Closure of 31 mitral PVLs was attempted. TSR was achieved in 29 cases. The FlexCath sheath was used in 16 cases and the Occlutech sheath was used in 15 cases. There were no adverse events. A paravalvular leak device (PLD) was used in 25 cases and the Amplatzer Vascular Plug III (AVP III; Abbott) was used in 6 cases. Repositioning of the PLD was required in 8 patients; in each case, this maneuver was performed in a controlled manner and without loss of the coaxial alignment between the steerable sheath and the PVL channel. The TS was not achieved in 2 cases, due in 1 case to inability to cross the PVL channel with a guidewire as a result of extreme channel angulation and in 1 case to lack of stability of one of the implanted AVP III devices, which required its removal prior to detachment and resulted in moderate residual paravalvular regurgitation. TSR was higher in procedures performed with a steerable sheath compared with the control group (93.5% vs 72.7%; P<.05). Median IT was significantly shorter in cases performed with a steerable sheath as compared with the control group (28.5 min [range, 15-58 min] vs 64 min [range, 35-180 min], respectively; P<.05).

Discussion

We successfully performed closure of 29 mitral PVLs using a steerable sheath. Our initial assumption regarding better stability and improved navigation in the left atrium was confirmed. The operator was able to easily locate the PVL channel, and stable position of the sheath facilitated quick crossing of the channel with two wires and a Judkins catheter. A PLD was used in most cases; after the ventricular disc was opened, the PLD could be freely reoriented to find the position that guaranteed the best result. Because of the coaxial alignment of the sheath, the PLD was also properly oriented in regard to the long axis of the PVL channel; therefore, we observed minimal repositioning of the device after detachment. In our opinion, this made the echocardiographic assessment prior to device release more related to the final result. Furthermore, due to the large inner diameter of these steerable sheaths, the operator could place a wire (usually V-18) in the left atrium through the sheath in addition to the delivery set. This approach guaranteed that an appropriate distance was kept between the sheath and the PVL channel, which was necessary to open the atrial disc of the PLD.

Since the sheaths that we used were not designed for PVL closure, there are certain limitations of our approach that should be mentioned. Operators would surely benefit from greater choice of distal curves (only one is available at the moment) and a dedicated valve for delivery sheath introduction. Despite improved maneuverability as compared with the traditional transseptal approach without a steerable sheath, the posterolateral location of the mitral PVL is still less favorable and requires more operator effort and experience.

It is important to stress that we achieved technical success in 93.5% of the attempted cases. A recent meta-analysis showed that in 274 patients who underwent mitral PVL closure, a 100% success rate was achieved only via transapical approach, whereas procedural success was achieved in only 66.4% of cases when an antegrade or retrograde approach was utilized.⁷ Therefore, steerable sheaths bring us closer to perfection without increasing periprocedural risk related to general anesthesia and apical approach. It was also shown that successful PVL closure was associated with lower cardiac mortality rate, improvement in functional class, and fewer surgical reinterventions;⁷ therefore, the high TSR achieved in our study should result in favorable clinical outcomes.

Observed differences in the prevalence of the closure devices used in both groups (AVP III vs PLD) should also be addressed. Choice of closure device is related not only to technical characteristics of the PVL channel, such as shape, size, and length, but also to expected difficulties with delivery and positioning of the device. Nowadays, we prefer to use the PLD, since it is the only device dedicated for PVL closure and has a wide array of sizes that allow us to find the best solution for any given situation. However, the PLD requires careful positioning in order to obtain satisfying results. The introduction of steerable sheaths allows the operator to control every aspect of the PVL closure procedure, including proper device orientation and implantation angle. This was not possible with our previous technique, when we preferred to use more AVP III occluders packed together to close the PVL because the success of this approach was not as dependent on implantation angle and orientation of the device(s). This change explains why the introduction of the steerable sheath allowed us to decrease the number of devices used for PVL closure. We also think that due to the above-mentioned differences between these implantation strategies, it is pointless to compare whether the number of devices implanted in both groups was statistically significant. Nowadays, the PLD is usually our initial choice for mitral PVL closure with the exception of PVLs around previously implanted closure devices that result in clinically significant hemolysis – in these cases, we prefer to use the AVP III.

Of course, the steerable sheaths that we used are not the only options available. The Agilis NxT steerable guide catheter (St. Jude Medical) has already been extensively tested both in our center and worldwide and has proved to be quite effective.⁸ However, operators should keep in mind that the Agilis sheath is available in three different distal curves (small, medium, and large) and failure to select an appropriate size can create difficulties in accessing the PVL channel. Furthermore, the Agilis sheath has a smaller diameter than the sheaths used in our study, and due to that fact it can only be used to find and cross the PVL channel and must then be exchanged for a delivery set.

Study limitations. An obvious limitation of the present study is the low number of treated PVLs. This will change over time, since the FlexCath sheath and the Occlutech steerable sheath are currently always the initial choice at our center whenever mitral PVL closure is attempted.

Conclusion

Steerable sheaths are safe and effective devices that support mitral PVL closure. They significantly shorten procedural time and allow for safety wire presence in the PVL channel. In addition, another stiff wire (a distance wire) can be placed in the left atrium to limit unintentional movement of the sheath into the left ventricle. Due to coaxial alignment of the sheath with the PVL channel, implanted devices have proper orientation, which makes the echocardiographic assessment prior to device detachment more accurate. Due to high TSR and an ability to reach mitral PVLs in all locations around the mitral annulus, steerable sheaths may be the preferred initial choice over transapical approach for mitral PVL closure due to their safety and simplicity, as well as the lack of general anesthesia required for the procedure.

References

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From the ¹Department of Cardiology and Structural Heart Diseases, Medical University of Silesia, Katowice, Poland; and the ²Cardiac Rehabilitation Department, Treatment and Rehabilitation Center, Long-Term Care Hospital, Jaworze, Poland.

Funding: The study was supported by a STRATEGMED II grant (National Centre for Research and Development, STRATEGMED2/269488/7/NCBR/2015).

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. All authors report personal fees and grant income from the National Center for Research and Development. Dr Smolka reports personal fees as a proctor for PVL closure for Occlutech and Abbott.

The authors report that patient consent was provided for publication of the images used herein.

Manuscript submitted August 19, 2018, provisional acceptance given September 19, 2018, final version accepted January 9, 2019.

Address for correspondence: Grzegorz Smolka, MD, 3rd Department Of Cardiology and Structural Heart Diseases, Medical University of Silesia, ul. Ziołowa 45, 40-635 Katowice, Poland. Email: gsmolka@me.com