Pocket Medicine: The Massachusetts General Hospital Handbook of Internal Medicine (15 page)

MVA proportional to S
₂
–OS interval (tighter

valve → ↑ LA pressure → shorter interval)

• Loud S
₁
(unless MV calcified)

Diagnostic studies

• ECG:
LAE
(“P mitrale”), ± AF, ± RVH

• CXR:
dilated LA
(straightening of left heart border, double density on right, left mainstem bronchus elevation) •
Echo
: estimate pressure gradient (∇), RVSP, valve area, valve echo score (0–16, based on leaflet mobility & thick., subvalvular thick., Ca
⁺⁺
); exer. TTE (to assess ∆ RVSP and ∇) if sx & severity of MS at rest discrepant; TEE to assess for LA thrombus before PMV

•
Cardiac cath
: ∇ from simultaneous PCWP & LV pressures, calculated MVA; LA pressure tall
a
wave and blunted
y
descent; ↑ PA pressures

Treatment (
NEJM
1994;331:961;
Circ
2002;105:1465 & 2008;118:e523;
EHJ
2012;33:2451)

• Medical: Na restriction, cautious diuresis, bB, sx-limited physical stress • Antibiotic Ppx recommended if h/o RHD w/ valvular disease for 10 y or until age 40

• Anticoag if: AF, prior embolism, LA thrombus; ? LA >55 mm or lg LA w/ spont contrast • Mechanical intervention if: heart failure sx w/ MVA ≤1.5, or

heart failure sx w/ MVA >1.5 but ↑ PASP, PCWP, or MV ∇ w/ exercise, or

asx Pts w/ MVA ≤1.5 and PHT (PASP >50 or >60 mmHg w/ exercise) or new-onset AF

•
Percutaneous mitral valvotomy
(PMV): preferred Rx if RHD; MVA doubles, ∇↓ by 50%;
MVR
if
valve score <8, ≤ mild MR,  AF or LA clot • Surgical (MV repair if possible, o/w replacement): consider in sx Pts w/ MVA ≤1.5

if PMV unavailable/contraindicated (mod. MR, LA clot), or valve morphology unsuitable

• Pregnancy: if NYHA class III/IV → PMV, o/w medical Rx w/ low-dose diuretic & bB

MITRAL VALVE PROLAPSE (MVP)

Definition and Etiology

• Billowing of MV leaflet ≥2 mm above mitral annulus in parasternal long axis echo view • Leaflet redundancy from myxomatous proliferation of spongiosa of MV apparatus • Idiopathic, familial and a/w connective tissue diseases (eg, Marfan’s, Ehlers-Danlos) • Prevalence 1–2.5% of gen. population,
>
(
NEJM
1999;341:1), most common cause of MR

Clinical manifestations (usually asymptomatic)

• MR (from leaflet prolapse or ruptured chordae); infective endocarditis; embolic events • Arrhythmias, rarely sudden cardiac death

Physical exam

• High-pitched, midsystolic click ± mid-to-late systolic murmur

• ↓ LV volume (standing) → click earlier; ↑ LV volume or afterload → click later, softer
Treatment

• Endocarditis prophylaxis no longer recommended (
Circ
2007:116:1736) • Aspirin or anticoagulation if prior neurologic event or atrial fibrillation

TRICUSPID REGURGITATION

•  Primary etiol: rheumatic, CTD, radiation, IE, Ebstein’s anomaly, carcinoid, tumors

•  Fxnal etiol: RV and/or pulm HTN (may be 2° to L-sided dis.), RV dilation and/or infarct

•  Consider repair, annuoplasty or replacement for sx and severe TR (eg, ERO ≥0.40 cm
²
)

PROSTHETIC HEART VALVES

Mechanical (60%)

•
Bileaflet
(eg, St. Jude Medical); tilting disk; caged-ball • Very durable (20–30 y), but thrombogenic and ∴ require anticoagulation

consider if age <~65 y or if anticoagulation already indicated ( 
JACC
2010;55:2413)

Bioprosthetic (40%)

• Bovine
pericardial
or porcine
heterograft
(eg, Carpentier-Edwards), homograft • Less durable, but min. thrombogenic; consider if >~65 y, lifespan <20 y or  anticoag
Physical exam

• Normal:
crisp sounds
, ± soft murmur during forward flow (normal to have small ∇) • Abnormal: regurgitant murmurs, absent mechanical valve closure sounds
Anticoagulation & antiplatelet therapy (
Circ
2008;118:e523;
JAMA
2012;308:2118)

• Assess for
high-risk features
: prior thromboembolism, AF, EF<30–35%, hypercoagulable •
Warfarin
: low-risk mech AVR: INR 2–3 (consider 2.5–3.5 for 1st 3 mo)

mech MVR or high-risk mech AVR: INR 2.5–3.5

high-risk bioprosthetic: INR 2–3 (and consider in low-risk for 1st 3 or even ? 6 mo)

•
ASA
(75–100 mg) for all prosthetic valves; avoid adding to warfarin if h/o GIB, uncontrolled HTN, erratic INR or >80 y;
ASA
+
clopidogrel
(or warfarin) × 3–6 mo after TAVR

• If thrombosis, ↑ intensity (eg, INR 2–3 → 2.5–3.5; 2.5–3.5 → 3.5–4.5; add ASA if not on)

Correction of overanticoagulation (
Circ
2008;118:e626)

• Risk from major bleeding must be weighed against risk of valve thrombosis • Not bleeding: withhold warfarin, give vit K 1–2.5 mg
PO
only if INR 5–10, ✓ serial INRs • Bleeding or INR >10: FFP ± low-dose (1 mg) vit K IV

Endocarditis prophylaxis: for all prosthetic valves (see “Endocarditis”)

Complications

• Structural failure (r/o endocarditis); mechanical valves: rare except for Bjork-Shiley; bioprosthetic valves: up to 30% fail rate w/in 10–15 y, mitral > aortic • Paravalvular leak (r/o endocarditis); small
central
jet of regurg is normal in mech. valves • Obstruction from thrombosis or pannus ingrowth: ✓ TTE, TEE and/or fluoroscopy if ? clot significantly sx
pannus
ingrowth: remove w/ surgery

thrombosis: surgery if L-sided valve & either severe sx or lg (? >1 cm) clot burden; lytic often
ineffective
for L-sided thrombosis & 12–15% risk of stroke; consider UFH ± lytic (? low-dose tPA via slow infusion,
JACC CV Imaging
2013;6:206) if mild sx & small clot burden or poor surg candidate; lytic reasonable for R-sided

• Infective endocarditis ± valvular abscess and conduction system dis. (see “Endocarditis”) • Embolization (r/o endocarditis); risk ~1%/y w/ warfarin (vs. 2% w/ ASA, or 4% w/o meds)

mech MVR 2 × risk of embolic events vs. mech AVR (
Circ
1994;89:635)

• Bleeding (from anticoag), hemolysis (esp. w/ caged-ball valves or paravalvular leak)

HEART VALVES (superior view,
JAMA
1976;235:1603)