LAUSR

Functional mitral regurgitation (FMR) is a common complication in patients with left ventricular dysfunction and is associated with poor outcomes. Remodelling, often as the result of heart failure (HF) with reduced ejection fraction (HFrEF) or myocardial infarction, causes annular dilatation and leaflet tethering, resulting in coaptation failure of an otherwise structurally healthy valve. Given the interplay of underlying ventricular disease with valvular dysfunction, treatment of FMR employs medical management of HF as well as structural interventions on the valvular apparatus, including leaflets, annulus, chordae and papillary muscles. Intervention approaches include surgery and, more recently, transcatheter edge-to-edge repair (TEER), transcatheter mitral repair using annuloplasty ring, and transcatheter mitral replacement. Guidelinedirected medical therapy (GDMT) remains a cornerstone for management of HFrEF patients and has been demonstrated to reduce FMR severity. GDMT drug classes, including angiotensin-converting enzyme inhibitors and angiotensin receptor blockers with or without a neprilysin inhibitor, beta-blockers, mineralocorticoid receptor antagonists, and now sodium–glucose cotransporter 2 inhibitors, have proven benefits in HF management but are difficult to optimize in clinical settings.1 The relative effectiveness of these approaches and how to optimize medical therapy in the context of FMR remains subject to debate. Recent trials have considered the role of TEER, most commonly MitraClip (Abbott, Abbott Park, IL, USA), in combination with maximally tolerated GDMT, with the COAPT study suggesting a mortality benefit while the MITRA-FR study found percutaneous valve intervention had no benefit compared to GDMT alone.2 This difference may be explained partially by the inclusion of sicker patients in MITRA-FR and those on less stringent GDMT regimens, both of which may be more representative of a real-world clinical practice.3 A more realistic picture of the management of FMR patients is needed to determine how to appropriately make decisions regarding percutaneous interventions. Here we aim to assess the clinical and echocardiographic profiles of patients presenting to our Heart Valve Center (HVC) for FMR evaluation to better characterize the balance of intervention and medical therapy in FMR management. This single-centre retrospective cohort study was conducted at the Columbia University Irving Medical Center (CUIMC) using electronic health records from our HVC registry to collect demographic, clinical, and echocardiographic data for all consecutive patients presenting for FMR evaluation from November 2016 to December 2020. Eligible patients had FMR evaluation as the primary reason for visit. Ethical approval was obtained through Columbia University IRB #6 (IRB00008612). A total of 107 FMR patients were included (Table 1). The mean age was 75 ± 10.3% and 48.6% were female. At presentation, 83.2% (n = 89) had moderate-to-severe FMR. Intervention was performed in 30.8% (n = 33) of patients (FMRINT) versus no intervention (FMRMED, n = 74), and was comprised of 21.2% (n = 7) surgical and 78.8% (n = 26) transcatheter therapies. New York Heart Association (NYHA) class ≥III was present in 51.5% of FMRINT and 33.8% of FMRMED. FMRINT patients generally had greater regurgitant volumes (71.3± 24.4 ml vs. 54.6 ± 25.9 ml in FMRMED). Reasons for deferred intervention included further medical optimization (40.5%), lack of clear treatment indication/absence of symptoms (38.7%), prohibitive risk (4.0%), patient refusal (4.0%) and lost/declined follow-up (12.0%). Prior medical therapy for HF occurred in 89.2% (n = 66) of FMRMED and 97.0% (n = 32) of FMRINT, with 83.8% of FMRMED and 97% of FMRINT patients on at least one fundamental HF drug class. Only 16.2% of FMRMED patients and 18.2% of FMRINT patients were on three or more classes of fundamental HF medications. Notably, sacubitril/valsartan was prescribed in 24.3% (n = 18) of FMRMED but only 12.1% (n = 4) of FMRINT patients. Of the 30 patients recommended for medical optimization, 18 were followed by CUIMC HF cardiologists, while 10 were lost to follow-up and two died prior to optimization. At initial HF consultation, 44.4% (n = 8) of patients added or increased sacubitril/valsartan, the leading regimen modification. By 6–10-month follow-up, sacubitril/valsartan use had increased the most (27.8–77.8%), along with that of betablockers and aldosterone antagonists (online supplementary Table S1). At follow-up, 83.3% (n = 15) were on an optimized regimen per their HF cardiologist, 11.1% (n = 2) were undergoing continued optimization, and 5.6% (n = 1) were considered for cardiac resynchronization therapy. Notably, no patients were recommended for mitral valve intervention at this timepoint. At follow-up, the number of patients at NYHA class III/VI reduced from 72.2% (n = 13) to 22.2% (n = 4). Notably, 38.9% (n = 7) of patients saw a reduction in NYHA class by follow-up; only 5.6% (n = 1) worsened. Eight of the 14 patients (57.1%) with complete echocardiographic data saw a reduction in mitral regurgitation severity. Of the 12 patients with complete echocardiographic and clinical data, only two remained both symptomatic and with moderate-severe mitral regurgitation, core criteria for TEER. From this single-centre study, we observe that patients frequently presenting with significant FMR yet are rarely on maximal GDMT, leaving ample room for optimization prior to possible intervention. It is important to note that the patient population reported is primarily from outside hospitals and clinics referring to our centre. Many of these centres lack a dedicated HF physician, and many patients are managed by internists, not cardiologists. One of the objectives of this report is to highlight the real-world disparity of GDMT in the community even in the current era in the US. While the finding is consistent with undermedication trends in the general HF population,4 existing FMR studies reflect cohorts with better GDMT at baseline, such as Koell et al.,5 which compared COAPT and MITRA-FR inclusion criteria but required preexisting optimized GDMT. Pagnesi et al.,6 which did evaluate mitral regurgitation in HF patients on suboptimal GDMT, also reported higher rates of medical therapy than the present study, likely in part due to a greater prevalence of severe disease (NYHA class ≥III 60% vs. 39%) and inpatient presentations (60% vs. 0%). The relatively poor baseline