How to manage severe mitral regurgitation (MR)?

From the Guidelines

Raising systemic vascular resistance (SVR) and decreasing pulmonary vascular resistance (PVR) is not necessarily bad in severe mitral regurgitation (MR), as the goal is to reduce regurgitant fraction and improve forward flow, but this should be done cautiously and with careful consideration of the individual patient's hemodynamics and clinical context, as stated in the 2023 guidelines 1. In the management of severe MR, the primary focus is on reducing symptoms and preventing or delaying the onset of left ventricular dysfunction.

• Medical therapy includes diuretics, ACE inhibitors, and beta-blockers to manage symptoms and reduce afterload.
• Surgical intervention, preferably mitral valve repair, is recommended for symptomatic patients with severe MR and for asymptomatic patients with evidence of left ventricular dysfunction or significant left ventricular dilation, as indicated in the 2023 guidelines 1.
• Transcatheter mitral valve repair (MitraClip) may be considered for high-surgical-risk patients with degenerative MR, as stated in the 2020 guidelines 1. The timing of intervention is critical, and regular echocardiographic monitoring is essential to assess for ventricular dilation or dysfunction that would trigger surgical referral, as recommended in the 2023 guidelines 1. Key considerations in the management of severe MR include:
• Symptom severity and left ventricular function
• Underlying etiology of MR
• Presence of atrial fibrillation or other comorbidities
• Patient's surgical risk and potential for durable repair
• Need for anticoagulation and rate control medications
• Regular monitoring and follow-up to assess for changes in clinical status or ventricular function, as emphasized in the 2007 guidelines 1 and the 2012 guidelines 1.

From the Research

Management of Severe Mitral Regurgitation

When managing severe mitral regurgitation (MR), several factors need to be considered, including the impact of systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) on the condition.

• Reducing SVR can be beneficial in severe MR, as it decreases the impedance to forward left ventricular output, thereby promoting greater forward stroke volume and reducing regurgitant fraction 2.
• Decreasing SVR with vasodilators like sodium nitroprusside can lead to significant reductions in pulmonary capillary mean and left ventricular end-diastolic pressures, while increasing cardiac index and forward stroke volume 2, 3.
• However, the management of severe MR also involves considering the effects on pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP), as increased PVR and PAP can lead to right heart dysfunction 4.
• In patients with severe MR, especially those with acute myocardial infarction, medical management has a poor prognosis, and surgery or transcatheter interventions may be necessary to improve survival 5.
• Severe functional mitral regurgitation (FMR) can have an unfavorable effect on pulmonary hemodynamics, increasing PVR, systolic PAP, and mean PAP, even when defined by updated European guidelines with a lower threshold 6.

Impact of SVR and OVR on Severe MR

• Raising SVR and decreasing OVR (output) in severe MR can be detrimental, as it increases the afterload on the left ventricle, potentially worsening the regurgitation and leading to decreased forward stroke volume and increased pulmonary pressures.
• The goal in managing severe MR is often to reduce SVR and increase forward stroke volume, while also considering the effects on PVR and pulmonary hemodynamics.
• Individual patient factors, such as the underlying cause of MR, presence of pulmonary hypertension, and right ventricular function, must be taken into account when determining the optimal management strategy.