Introduction

Left ventricular outflow tract (LVOT) obstruction is a well-recognized and potentially life-threatening complication of transcatheter mitral valve replacement (TMVR), particularly in valve-in-mitral annular calcification (ViMAC) procedures. The risk results from interactions between the anterior mitral leaflet, the septal contour, and the prosthetic valve. These interactions may cause either dynamic or fixed obstruction after device deployment. Recent studies have highlighted the importance of preprocedural assessment of LVOT obstruction risk using advanced multimodality imaging. To mitigate the risk of LVOT obstruction—particularly in anatomically complex cases with borderline or unfavorable neo-LVOT dimensions—several procedural strategies, such as Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction (LAMPOON) and Balloon-Assisted Translocation of the Mitral Anterior Leaflet (BATMAN), have been developed and have shown promising results.^1-4 Here, a high-risk patient who underwent a transcatheter ViMAC procedure using the BATMAN technique to prevent LVOT obstruction has been presented.

Case Report

A 72-year-old female with severe mitral stenosis (Pressure gradient max/mean: 16/10 mm Hg, mitral valve area: 1.5 cm²) and moderate mitral regurgitation was evaluated for mitral valve intervention. Multimodality imaging, including preprocedural transesophageal echocardiography (TEE) and computed tomography (CT), revealed severe circumferential mitral annular calcification extending into the basal and leaflet segments. Commissural fusion was absent, consistent with degenerative rather than rheumatic mitral stenosis. Therefore, balloon valvuloplasty was not considered a suitable treatment option. Given her advanced age, comorbidities (severe chronic obstructive pulmonary disease and morbid obesity (body mass index: 36.1 kg/m²)), and elevated the Society of Surgeons (11.6%), the patient was considered at prohibitively high risk for open-heart surgery. The Heart Team concluded that TMVR offered the most appropriate strategy. Preprocedural multimodality imaging, including TEE and electrocardiography-gated cardiac CT, was performed to assess anatomical suitability, prosthesis sizing, and the risk of LVOT obstruction. Transesophageal echocardiography showed an anterior mitral leaflet length of 3.05 cm (Figure 1A). Computed tomography demonstrated severe mitral annular calcification (MAC) (calcium volume 2488.3 mm²) with a MAC score of 9. The predicted neo-LVOT area was 146.2 mm² and the skirt neo-LVOT area 321.5 mm² at 45% systole (Figure 1B-D), indicating a high risk of obstruction.⁵ Owing to the predicted small neo-LVOT area, adjunctive strategies to mitigate obstruction risk, anterior leaflet modification such as LAMPOON or BATMAN, were considered as part of procedural planning.

Under general anesthesia and 3D TEE imaging guidance. Although the potential benefits of cerebral protection in high-risk TMVR cases are evident, cerebral protection devices could not be used during this procedure due to limited device availability in the country. First, bilateral femoral arterial and venous access was obtained, and 6F sheaths were placed. A transseptal puncture was performed via the right femoral vein using an inferoposterior approach. An 8.5F steerable Agilis catheter (Agilis NxT Steerable Introducer; St. Jude Medical, Inc, St. Paul, Minnesota, USA) was advanced into the left atrium. A coaxial system was created using a 7F JR4 guiding catheter inside the Agilis catheter, containing a Finecross microcatheter (Terumo Corporation, Tokyo, Japan) and a 300 cm 0.014″ Astato XS 20 (Asahi-Intecc, Tokyo, Japan) coronary guidewire (Figure 2A). A pigtail catheter was positioned in the non-coronary cusp to facilitate orientation. The coaxial system was carefully advanced to contact the anterior mitral leaflet. Rapid ventricular pacing at 150 bpm was applied to stabilize leaflet motion during positioning and electrification. Leaflet perforation was achieved using 10 W electrocautery applied to the denuded wire tip. Simultaneous 5% dextrose infusion prevented coagulum formation. Successful leaflet traversal was confirmed by TEE, and the microcatheter was advanced into the left ventricle. The Astato XS 20 wire was then exchanged for a 300 cm 0.014″ Pilot 50 wire (Abbott Vascular, Santa Clara, CA, USA). Over this wire, a 4.0 × 20 mm non-compliant coronary balloon (Shunmei Medical Co., Guangdong, China) was advanced, and an intentional laceration of the anterior mitral leaflet was created (Figure 2B), confirmed by the presence of a secondary mitral regurgitation jet on TEE. Following leaflet laceration, the JR4 catheter was advanced into the left ventricle, and a 300 cm 0.035″ pre-shaped Safari wire (Boston Scientific, Marlborough, MA, USA) was positioned. To facilitate valve delivery, a double-wire technique was used. For this purpose, a 90 cm 7F Destination sheath (Terumo Corporation, Tokyo, Japan) was advanced over the Safari guidewire into the left ventricle. Through this sheath, a second 0.035″ Back-Up Meier™ guidewire (Boston Scientific, Marlborough, MA, USA) was introduced to provide additional support for device delivery (Figure 2C). Subsequently, the destination sheath was withdrawn from the right femoral vein. Over the Back-Up Meier guidewire, a 10F sheath was advanced, and over the Safari guidewire, a 14F Python sheath (Meril Life Sciences, Gujarat, India) was introduced via the right femoral vein. Over the 10F sheath and Back-Up Meier wire, a 16 × 40 mm balloon (Meril Life Sciences, Gujarat, India) was advanced; over the 14F Python sheath and Safari wire, the previously sized 32 mm Myval valve (Meril Life Sciences, Gujarat, India) was delivered. Initially, balloon atrial septostomy was performed using the 16 × 40 mm balloon (Figure 2D). Following septostomy, the 32 mm Myval valve was advanced into the left atrium, while the 16 × 40 mm balloon was positioned across the anterior mitral leaflet (Figure 2E). Prior to anterior leaflet translocation, intra-aortic balloon pump support was established via the femoral artery to maintain hemodynamics during the critical phase. The 16 × 40 mm balloon was then positioned across the anterior leaflet and inflated to complete the BATMAN technique, displacing the anterior leaflet into the LVOT (Supplemental Video 2 and Video 3). After leaflet laceration with the 16 × 40 mm balloon, the balloon was withdrawn. The 32 mm Myval valve was then advanced from the left atrium to the implantation site defined by MAC anatomy. Under rapid ventricular pacing, the valve was deployed slowly and gradually with minimal forward and backward movement to ensure optimal positioning (Figure 2F) (Supplemental Video 1). The procedure was completed successfully without complications. Post-implantation hemodynamic and 2D and 3D TEE assessments confirmed optimal valve positioning, with no evidence of paravalvular leak, residual mitral regurgitation, or LVOT gradient (Supplemental Videos 4 and 5). Additionally, postprocedural computed tomography clearly demonstrated the spatial relationship between the implanted transcatheter valve and extensive mitral annular calcification in both en-view and en-face orientations (Figure 3A and B) (Supplemental Video 6). The patient was discharged in stable and improved clinical condition 3 weeks following her initial admission. At the 3-month follow-up, transthoracic echocardiography demonstrated a well-seated transcatheter valve with no paravalvular leak, a mean transmitral gradient of 4 mmHg, and preserved left ventricle function. Clinically, the patient improved from New York Heart Association class III to class II, confirming sustained symptomatic and hemodynamic benefit.

Discussion

Among adjunctive strategies to mitigate LVOT obstruction during TMVR, particularly in ViMAC procedures, LAMPOON and BATMAN techniques have emerged as viable options, each with distinct advantages and limitations. Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction enables controlled midline laceration of the anterior mitral leaflet via transcatheter electrosurgery, offering a fully percutaneous approach that preserves leaflet mobility and physiological flow, but it requires advanced operator expertise, specialized equipment, and carries risks such as incomplete laceration or leaflet perforation. Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction is well established for LVOT obstruction prevention. Balloon-Assisted Translocation of the Mitral Anterior Leaflet, however, eliminates the need for electrosurgery and complex traversal, making it simpler and potentially easier to reproduce in less experienced centers. The BATMAN technique uses balloon inflation to mechanically displace the anterior mitral leaflet away from the left ventricular outflow tract, providing immediate and visible retraction that facilitates precise valve deployment without the need for prolonged electrosurgical manipulation. Nevertheless, BATMAN is less widely adopted, may be less precise in leaflet manipulation, and may carry a higher risk of leaflet recoil post-implantation. Balloon-Assisted Translocation of the Mitral Anterior Leaflet may be preferred in cases with hostile anatomy or heavily calcified, bulky anterior mitral leaflets, where it minimizes the risk of myocardial injury and serves as a safer alternative to electrosurgical laceration, while LAMPOON is typically favored in patients with thin, mobile leaflets and a small predicted neo-LVOT; the choice of technique should be individualized. Detailed preprocedural imaging and anatomical risk assessment are essential for planning.^6-8 Although broader validation is still needed, early experiences suggest that BATMAN may serve as a practical alternative to LAMPOON in anatomically complex or high-risk ViMAC cases. Helmy et al⁹ first described the transapical BATMAN technique in 2020. In 3 high-risk patients, anterior leaflet perforation and ballooning achieved complete success without LVOT compromise.⁹ More recently, Parekh et al¹⁰ reported the first transseptal ViMAC case in 2025, demonstrating safe leaflet translocation and uneventful valve implantation. These individual experiences have been supported by data in which patients benefited from high technical success and low procedural mortality (Table 1).^9-15 To date, while Kılıç et al¹⁶ have reported the use of the LAMPOON technique in a case of transcatheter mitral valve-in-ring implantation, the BATMAN technique has not been previously performed or published in valve-in-MAC (ViMAC) procedures in Türkiye. This case is the first to demonstrate the use of transeptal BATMAN during a ViMAC intervention in the country and uniquely demonstrates a step-by-step execution of the procedure using the double kissing wire technique, providing both a technical roadmap and proof of feasibility in this anatomically complex scenario.

Despite its technical simplicity, the BATMAN technique has several limitations. Leaflet recoil or reversion may occur, potentially compromising the intended LVOT area. The long-term durability of leaflet translocation and its impact on valve hemodynamics remain uncertain, as current data are limited to case reports and small series (Table 1).^9-15 Furthermore, while technically less demanding than LAMPOON, BATMAN still requires advanced structural expertise, and its reproducibility in less experienced centers may be limited. These issues underscore the need for further multicenter evaluation and long-term follow-up studies.

Another important aspect is the role of cerebral protection devices during high-risk TMVR procedures. In this case, such devices could not be used due to limited availability in the country. Although no cerebrovascular complications occurred peri- or post-procedurally, the potential benefit of cerebral protection in preventing embolic events remains evident. Future widespread access to these devices may further improve the safety profile of complex transcatheter mitral interventions.

Conclusion

For patients with a high-risk anatomy undergoing TMVR, preventing LVOT obstruction remains a critical challenge. In patients with high-risk anatomy undergoing TMVR, the BATMAN technique offers a feasible, simple, and safe mechanical alternative to electrosurgical approaches for anterior leaflet management, representing a more accessible and reproducible option—particularly in anatomically complex ViMAC cases.

No artificial intelligence (AI)-assisted technologies (such as Large Language Models, chatbots, or image creators) were used in the production of submitted work.

Footnotes

Informed Consent: Informed consent was obtained from the patient.

Declaration of Interests: The authors have no conflicts of interest to declare.

Video 1: Step-by-step fluoroscopic demonstration of the BATMAN technique, showing all procedural steps from transseptal access to final transcatheter mitral valve implantation.

Video 2: Intraprocedural TEE showing leaflet laceration and anterior displacement during the BATMAN technique.

Video 3: Intraprocedural TEE clearly showing a secondary mitral regurgitation jet originating from the anterior mitral leaflet, demonstrating the effectiveness of the BATMAN technique.

Videos 4 and 5: Postprocedural 2D (4) and 3D (5) TEE demonstrating optimal valve positioning with no paravalvular leak, no residual mitral regurgitation, and no LVOT gradient.

Video 6: Postprocedural CT demonstrating the relationship between the implanted valve and severe mitral annular calcification.

References

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