International LAMPOON: first European experience with laceration of the anterior mitral valve leaflet prior to transseptal transcatheter mitral valve implantation

A Modified Tip-to-Base LAMPOON to Prevent Left Ventricular Outflow Tract Obstruction in Valve-in-Ring or Valve-in-Valve Transcatheter Mitral Valve Replacement

Background

The Laceration of the Anterior Mitral leaflet to Prevent Outflow ObtructioN (LAMPOON) procedure may be performed from the leaflet tip to base to prevent left ventricular outflow tract obstruction (LVOTO) in patients with high-risk anatomy undergoing valve-in-valve (VIV) or valve-in-(complete)-ring (VIR) transcatheter mitral valve replacement (TMVR).

Methods and Results

Thirteen consecutive patients (6 females, average age 67.7 years) with a mean left ventricular ejection fraction of 60%, a median STS score of 3.2%, and degenerative surgical mitral bioprosthesis or ring were treated with a combined, single-stage procedure of preventive LAMPOON and trans-septal TMVR with SAPIEN 3 valves (Edwards Lifesciences, Irvine, CA). Under real-time 3-dimensional transesophageal echocardiography (RT 3D-TEE) guidance, we included the rendezvous technique in the LAMPOON procedure, and all 13 patients were successfully treated by tip-to-base LAMPOON and TMVR. The use of a modified LAMPOON procedure, aided by a rendezvous technique and guided by RT 3D-TEE imaging, offers precise guidance for positioning and aligning the guidewire. This approach not only reduces the need for fluoroscopy and shortens procedure times, but also significantly increases the likelihood of a successful outcome. Importantly, none of the patients in our study experienced unintentional aortic or aortic valve injuries, nor did they develop significant LVOTO following TMVR. In 11 of the 13 (85%) patients, we used a transcatheter SENTINELTM cerebral protection device (Boston Scientific, Marlborough, MA) for stroke prevention and capture of debris ≥ 2 mm were detected in 8/11 (73%) of the cases.

Conclusions

Utilizing intra-operative RT 3D-TEE in conjunction with the rendezvous technique can make the tip-to-base LAMPOON procedure even safer and more effective for patients undergoing VIV or VIR TMVR. Our study also suggests that cerebral protection is indicated in patients undergoing TMVR.

Assessing the Hemodynamic Impact of Anterior Leaflet Laceration in Transcatheter Mitral Valve Replacement: An in silico Study

Background

A clinical study comparing the hemodynamic outcomes of transcatheter mitral valve replacement (TMVR) with vs. without Laceration of the Anterior Mitral leaflet to Prevent Outflow Obstruction (LAMPOON) has never been designed nor conducted.

Aims

To quantify the hemodynamic impact of LAMPOON in TMVR using patient-specific computational (in silico) models.

Materials

Eight subjects from the LAMPOON investigational device exemption trial were included who had acceptable computed tomography (CT) data for analysis. All subjects were anticipated to be at prohibitive risk of left ventricular outflow tract (LVOT) obstruction from TMVR, and underwent successful LAMPOON immediately followed by TMVR. Using post-procedure CT scans, two 3D anatomical models were created for each subject: (1) TMVR with LAMPOON (performed procedure), and (2) TMVR without LAMPOON (virtual control). A validated computational fluid dynamics (CFD) paradigm was then used to simulate the hemodynamic outcomes for each condition.

Results

LAMPOON exposed on average 2 ± 0.6 transcatheter valve cells (70 ± 20 mm² total increase in outflow area) which provided an additional pathway for flow into the LVOT. As compared to TMVR without LAMPOON, TMVR with LAMPOON resulted in lower peak LVOT velocity, lower peak LVOT gradient, and higher peak LVOT effective orifice area by 0.4 ± 0.3 m/s (14 ± 7% improvement, p = 0.006), 7.6 ± 10.9 mmHg (31 ± 17% improvement, p = 0.01), and 0.2 ± 0.1 cm² (17 ± 9% improvement, p = 0.002), respectively.

Conclusion

This was the first study to permit a quantitative, patient-specific comparison of LVOT hemodynamics following TMVR with and without LAMPOON. The LAMPOON procedure achieved a critical increment in outflow area which was effective for improving LVOT hemodynamics, particularly for subjects with a small neo-left ventricular outflow tract (neo-LVOT).

Hemodynamics rounds: Hemodynamics of mitral valve interventions

Mitral valvulopathy presents as regurgitation, stenosis, or mixed disease and can occur in both native and prosthetic valves. Such disease develops in conjunction with pathophysiologic changes in the left atrium (LA) and drives changes in LA compliance, pressure, and thus clinical syndromes. With advances in the understanding and treatment of structural heart disease and in the setting of higher-risk patient populations, less-invasive transcatheter approaches have become increasingly commonplace in the treatment of mitral valve disease. Over time, transcatheter mitral valve interventions have evolved to include paravalvular leak closure, mitral valve repair, and mitral valve replacement. Parallel to this evolution, advances in invasive intracardiac pressure monitoring, particularly at the level of the LA, have also occurred. These advances emphasize the unique interplay between mitral valve disease and LA function; account for limitations of noninvasive assessment; and guide beneficial outcomes in each area of transcatheter mitral valve intervention. As a result, continuous transseptal LA pressure monitoring has developed into an indispensable instrument in successful percutaneous mitral valve intervention, complementing traditional noninvasive assessment.