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). 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. 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.