WASHINGTON – One transcatheter device designed to prevent left ventricular outflow tract (LVOT) obstruction relevant to transcatheter mitral valve replacement (TMVR) and another designed to prevent coronary obstruction relevant to transcatheter aortic valve replacement (TAVR) performed well in feasibility studies, according to data presented in two separate late breaking clinical trial sessions at the CRT 2019, sponsored by MedStar Heart & Vascular Institute.
LVOT obstruction prevention
“The 30-day survival in subjects with an increased risk of LVOT obstruction was significantly better than that previously reported in registries,” said Jaffar M. Khan, BM BCh, of the National Heart, Lung, and Blood Institute, who addressing results with the LAMPOON device prior to TMVR,.
is an acronym for intentional Laceration of the Anterior Mitral valve leaflet to Prevent LVOT ObstructioN. Introduced percutaneously and guided to the valve with wires, it was designed to tear existing mitral valve leaflets to prevent them from causing life-threatening LVOT obstruction. It is used immediately prior to TMVR in patients at risk for this complication.
In a feasibility study, delivery, deployment, and retrieval of the device was achieved in all 30 patients. On the basis of the primary endpoint of LVOT gradients of less than 50 mm Hg and no emergency surgery, the procedural success was 73%. The 30-day survival was 93%.
Citing data from registries, Dr. Khan said that the expected survival in TMVR patients with LVOT obstruction caused by a native mitral valve leaflet has been less than 40%. With few existing options to prevent this complication, none of which are reliable, LAMPOON is poised to permit patients who are poor candidates or are contraindicated for TMVR to undergo this treatment, according to Dr. Khan.
“LAMPOON is feasible in all anatomies and calcium patterns,” said Dr. Khan, who noted that gradients of less than 30 mm Hg was achieved in 29 of the 30 patients. Although Dr. Khan acknowledged that this study was small and uncontrolled, and he further cautioned that current strategies for predicting mitral valve leaflet LVOT obstruction are “imprecise,” he believes larger studies of LAMPOON are warranted based on these results.
Coronary artery obstruction prevention
Dr. Khan also presented data on the BASILICA device from a second feasibility study. The device is employed immediately prior to TAVR in order to prevent large aortic valve leaflets, whether native or from an existing bioprosthetic valve, from producing coronary obstruction. BASILICA is an acronym for Bioprosthetic Aortic Scallop Intentional Laceration to prevent Iatrogenic Coronary Artery obstruction.
This device is also introduced percutaneously and uses radiofrequency ablation to split leaflets that are considered to pose a risk for coronary obstruction. Even though Dr. Khan acknowledged that there is also a lack of precision for predicting which TAVR candidates require an intervention to prevent coronary obstruction, he cited mortality rates exceeding 40% when this complication occurs.
In the feasibility study, 30 patients, of whom 80% were female, were enrolled. In half of the cases, the target for BASILICA was a native valve. The remainder was treated for risk of coronary obstruction posed by a bioprosthetic valve. Multiple comorbidities, including a high proportion with prior stroke, made those selected for enrollment poor candidates for surgery.
The BASILICA intervention was successful in 28 of the 30 participants and in 35 of the 37 leaflets treated. At 30 days, there was one death and one disabling stroke. The overall success rate of the procedure was 93%, according to Dr. Khan.
“One hundred percent of patients were discharged from the cath lab without coronary obstruction despite the high baseline risk,” Dr. Khan said. Again, larger studies are needed to validate the safety and efficacy of this approach, but Dr. Khan believes the outcomes in this study warrant expanded clinical studies.