Mitral valve prolapse (MVP) is among the most common valve disorders in Western countries, primarily caused by fibroelastic deficiency, Barlow’s disease, and mixed pathologies. About 25 % of patients can have progressive mitral regurgitation (MR) with an elevated risk of sudden cardiac death and mortality. An elevated risk of ventricular arrhythmia (VA) contributes to poorer outcomes in a subset of individuals who have MVP without or with MR. Barlow’s disease, bileaflet MVP, and mitral annular disjunction (MAD) are risk factors linked with VA.
MAD occurs when the mitral annulus separates from the atrioventricular junction during systole. VA is caused by increased leaflet mobility, which accelerates papillary muscle fibrosis, leaflet prolapse, and valvular degeneration. Mitral valve surgery is performed to reduce the mechanical stress of MAD. However, it is not sufficient because of the inherent complexity of mitral valve pathology. Severe MR can persist after the surgery because of irreversible structural alteration.
A retrospective cohort study published in the European Heart Journal has found a significant link between MAD and an increased risk of VA in patients who are having surgical repair for MVP.
The study included patients diagnosed with MVP and mild to severe degenerative MR who underwent surgery for MVP or replacement from 2010 to 2022 at Karolinska University Hospital, Stockholm, Sweden. Exclusion criteria were if pre- and post-operative echocardiograms were not found, the patient had ischemic heart disease, history of percutaneous coronary intervention, myocardial infarction, coronary bypass grafting, concomitant or previous aortic valve intervention, endocarditis, rheumatic mitral valve disease, mitral valve stenosis, channelopathy, or primary cardiomyopathy.
ECG recordings, electronic medical records, and echocardiograms, used to detect MAD, were analyzed to obtain data on patients’ characteristics and results. The Swedish Ethical Review Authority gave ethical approval. The main study exposures were no MAD and MAD. The primary study exposures were MAD and no MAD. Each patient’s follow-up continued from the start date to 31st August 2023. No observation before surgery is included.
Of 599 patients, 485 (81%) had MVP and 114 (19%) received valve replacement. With a median length at the end systole of 8.0 mm [inter-quartile range (IQR) 5.0 to 10.0], 96 (16%) of patients showed MAD. Thirty-nine cases were identified as having pseudo-MAD. The median time of the 1st and 2nd visits after the surgery was 44 days (IQR 37 to 55) and 109 days (IQR 80 to 185), respectively. Statistical analyses were performed using RStudio and IBM SPSS Statistics. During the median follow-up of 5.5 years (IQR 2.8 to 7.5), MAD patients had an increased risk of post-operative VA [hazard ratio (HR) adjusted for age and sex 3.33, 95% confidence interval (CI) 1.37-0.08, Pinteraction= 0.01].
This study’s limitations include an underestimation of the prevalence of MAD in echocardiography, data collection without a central event adjudication committee, the underestimation of the silent VA incidence, and the lack of pre-operative VA data.
MAD is more prevalent in women and linked with Barlow’s disease, mitral valve surgery at a young age, and a high long-term VA risk following the surgery. MAD in a patient who has MR and MVP was linked with a 3-fold elevated long-term risk of VA with post-mitral valve surgery, although with the correct anatomy of MAD.
Reference: Lodin K, Da Silva CO, Wang Gottlieb A, et al. Mitral annular disjunction and mitral valve prolapse: long-term risk of ventricular arrhythmias after surgery. Eur Heart J. doi:10.1093/eurheartj/ehaf195
