Kissing balloon technique as rescue strategy to treat left ventricular outflow tract obstruction after transcatheter mitral valve replacement: a case report

Background: Transcatheter mitral valve replacement (TMVR) has become a viable, minimally invasive treatment for inoperable patients with severe mitral valve disease, particularly among elderly individuals with significant comorbidities. A key complication of TMVR is left ventricular outflow tract (LVOT) obstruction, necessitating various preventive and therapeutic strategies. This report presents a case of severe LVOT obstruction following TMVR and highlights the effective application of the kissing balloon technique as a therapeutic intervention. Case summary: A 79-year-old female with New York Heart Association Class IV dyspnoea due to severe mitral stenosis and a high operative risk, with a Society of Thoracic Surgeons Risk of Mortality (STS-PROM) score of 6.2%, underwent TMVR. Pre-procedural evaluations indicated significant mitral valve calcification and a mitral valve area of 0.9 cm². After successful TMVR deployment, post-implantation echocardiography revealed an LVOT pressure gradient of 53/85 mmHg, prompting the use of the kissing balloon technique, which reduced the gradient to 28 mmHg. Follow-up assessments showed normal mitral valve function and stable LVOT gradients during short-term follow-up throughout the patient's hospital stay. Discussion: Left ventricular outflow tract obstruction is a potentially life-threatening complication of TMVR, often associated with high mortality rates due to haemodynamic impairment. This complication can arise from various anatomical factors and valve positioning issues. Several strategies have been developed to address LVOT obstruction, including the laceration of the anterior mitral leaflet and alcohol septal ablation. The successful implementation of the kissing balloon technique in this case underscores its potential to improve outcomes in LVOT obstruction.