Mitral Valve Regurgitation: Pathophysiology, Staging, Treatment & Follow-Up
Pathophysiology
Mitral regurgitation (MR) = systolic backflow from LV → LA due to incomplete leaflet coaptation. Causes volume overload → LA/LV dilation → eventual systolic dysfunction.
Etiology (Carpentier Classification)
| Type | Mechanism | Examples |
|---|
| Type I (Normal leaflet motion) | Annular dilation, leaflet perforation | Functional MR (dilated CM), endocarditis, trauma |
| Type II (Excessive motion / prolapse) | Chordal rupture/elongation, leaflet redundancy | Myxomatous degeneration (Barlow's, fibroelastic deficiency), endocarditis |
| Type IIIa (Restricted opening) | Leaflet thickening/fusion | Rheumatic MS+MR, carcinoid, lupus |
| Type IIIb (Restricted closing) | LV dilation → papillary displacement, tethering | Ischemic CM, non-ischemic dilated CM (functional MR) |
Staging (ACC/AHA 2020)
| Stage | Definition | Key Parameters |
|---|
| A (At risk) | Risk factors, no MR | — |
| B (Progressive) | Mild-moderate MR, preserved LV | EROA <20 mm², RegVol <30 mL, LVEF >60% |
| C (Severe asymptomatic) | Severe MR, preserved LV | EROA ≥40 mm² (primary) / ≥30 (secondary), RegVol ≥60/45, LVEF >60%, LVESD <40 mm |
| D (Severe symptomatic) | Severe MR + symptoms/LV dysfunction | NYHA II–IV, LVEF ≤60% or LVESD ≥40 mm, PA systolic >50 mmHg |
EROA = effective regurgitant orifice area; RegVol = regurgitant volume; LVESD = LV end-systolic dimension.
Clinical Presentation
- Chronic: Exertional dyspnea, fatigue, orthopnea, palpitations (AF common), peripheral edema (late).
- Acute (chordal rupture, endocarditis, papillary muscle rupture): Pulmonary edema, cardiogenic shock – emergency surgery.
Diagnostic Evaluation
- TTE (transthoracic echo): Primary – severity (vena contracta, PISA/EROA, RegVol, jet area), LV size/function, PA pressure, mechanism.
- TEE: Pre-op planning; better leaflet visualization, detect perforation/flail.
- Stress echo: Assess dynamic MR, contractile reserve, PA pressure with exercise.
- Cardiac MRI: Gold standard volumes, fibrosis (LGE), forward flow.
- Cath: If CAD suspected or pre-op coronary anatomy.
Management
Medical (Stage B–C)
- GDMT for HFrEF (ACEi/ARB/ARNI, β-blocker, MRA, SGLT2i) if LV dysfunction.
- Diuretics for congestion.
- Anticoagulation if AF.
- No vasodilators for chronic primary MR (no mortality benefit).
Interventional / Surgical (Stage C–D)
| Indication | Preferred Approach |
|---|
| Primary MR, severe, symptomatic (D) or LV dysfunction (C) | Mitral valve repair (preferred) > replacement. Chordal preservation. |
| Primary MR, asymptomatic, LVEF ≤60% or LVESD ≥40 mm | Surgery (Class I) |
| Secondary MR (functional), symptomatic on GDMT | GDMT optimization → TEER (MitraClip) if suitable anatomy (COAPT criteria); surgery if CABG needed |
| Acute severe MR | Emergency surgery (repair if possible) |
Follow-Up
- Stage B: Echo annually.
- Stage C: Echo q6–12mo; stress echo if asymptomatic.
- Post-repair: Echo at 1, 6, 12 mo then annually; monitor for recurrent MR, SAM, stenosis.
- Post-replacement: Anticoagulation (mechanical: warfarin INR 2.5–3.5; bioprosthetic: 3–6 mo then aspirin).
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