Mitral Valve diseases Flashcards
what is the aetiology of mitral regurg?
Primary MR (organic): mitral regurgitation caused by direct involvement of the valve leaflets or chordae tendinae
Degenerative mitral valve disease (mitral valve prolapse, mitral annular calcification, ruptured chordae tendinae)
Rheumatic fever
Infective endocarditis
Ischemic MR (e.g., papillary muscle rupture following acute MI)
Secondary MR (functional): caused by changes of the left ventricle that lead to valvular incompetence
Coronary artery disease or prior myocardial infarction causing papillary muscle involvement
Dilated cardiomyopathy (e.g., peripartum cardiomyopathy) and left-sided heart failure
Acute MR: Acute dysfunction of the mitral valve leads to volume overload and symptoms of acute heart failure.
Chronic MR
To preserve cardiac output, valve dysfunction is initially compensated for by cardiac remodeling.
Over time, remodeling affects LVEF, leading to heart failure
what is the pathophysio of mitral valve regurg?
Acute MR → ↑ LV end-diastolic volume → rapid ↑ LA and pulmonary pressure → pulmonary venous congestion → pulmonary edema
Chronic (compensated) MR: progressive dilation of the LV (via eccentric hypertrophy) → ↑ volume capacity of the LV (preload and afterload return to normal values) → ↑ end-diastolic volume → maintains ↑ stroke volume (normal EF)
Chronic (decompensated) MR: progressive LV enlargement and myocardial dysfunction → ↓ stroke volume → ↑ end-systolic and end-diastolic volume → ↑ LV and LA pressure → pulmonary congestion, possible acute pulmonary edema, pulmonary hypertension, and right heart strain
what are the clinical features of mitral regurg?
acute MR:
Dyspnea
Symptoms of left-sided heart failure
Signs and symptoms of pulmonary edema (e.g., bibasilar, fine, late inspiratory crackles)
Cardiogenic shock: poor peripheral perfusion, tachycardia, tachypnea, and hypotension
Palpitations [6]
Auscultation [5]
Soft, decrescendo murmur
No murmur in severe regurgitation with LV systolic dysfunction or hypotension [7]
Potentially: S3 heart sound
Chronic mitral regurgitation
Signs and symptoms
Dyspnea (including exertional dyspnea), dry cough
Fatigue [6]
Palpitations [8]
Symptoms of left-sided heart failure (potentially also symptoms of right-sided heart failure)
Auscultation [6]
Lateral displacement of the apical impulse
Quiet S1 heart sound
S3 heart sound in advanced stages of disease
S4 heart sound may be heard in functional MR.
Holosystolic murmur (high-pitched, blowing)
Radiates to the left axilla and heard best over the apex (5th intercostal space at the left midclavicular line)
Intensity can be increased by increasing preload (e.g., leg raise) or afterload (e.g., handgrip, squatting) due to increased regurgitation.
what is the classification of mitral regurg?
AHA staging for mitral valve regurgitation [9][10] Stage Extent of mitral regurgitation A At risk of MR (minimal regurgitation) B Progressive MR (moderate regurgitation) C1 Asymptomatic severe MR (LVEF > 60%) C2 Asymptomatic severe MR (LVEF ≤ 60%) D Severe symptomatic MR
what are the diagnostics of mitral regurg?
Transthoracic echocardiography (TTE) is used to confirm the diagnosis and classify severity in patients with suspected MR. Check ECG and troponin in acute MR to rule out myocardial infarct. Consider additional diagnostics (e.g., coronary angiography, blood cultures) depending on patient stability and the suspected underlying condition.
- Echocardiography
Indications: to assess the valve apparatus, size and function of left ventricle and atrium, and grade the severity of MR
TTE: modality of choice for the initial assessment of all patients with suspected valvular abnormality [5][6]
Transesophageal echocardiography (TEE): indicated prior to surgery and during the diagnostic workup of MR if TTE is inadequate [1][6]
Findings:
Echocardiographic characteristics of primary mitral regurgitation Parameter Acute MR Chronic MR Valve movement or function Abnormal Abnormal Aortic valve opening [12] Decreased Decreased Pulmonary vein flow [13] May be reversed Generally normal Left atrium Normal Dilated Left ventricle size Normal Increased/remodeled LVEF Normal Compensated: normal or increased [14] Decompensated: decreased [15] Pulmonary artery pressure [16][17] Elevated Compensated: normal Decompensated: elevated Right ventricle ejection fraction Normal Compensated: normal Decompensated: reduced [16][18]
- Laboratory studies
Troponin: Elevation may indicate myocardial ischemia.
BNP
Acute MR: typically normal because of the acute onset of symptoms [19]
Chronic MR: normal or elevated as regurgitation severity increases and the left ventricle is remodeled [6][20]
Blood cultures: in suspected infective endocarditis (at least three sets) [21]
Myocardial infarction must be ruled out in patients presenting with acute mitral regurgitation! - ECG
Acute MR: Findings are often nonspecific.
Normal sinus rhythm
Sinus tachycardia with nonspecific ST and T-wave abnormalities [5]
Atrial fibrillation [6]
Signs of acute ischemia in ischemic MR (see acute coronary syndrome)
Chronic MR: ECG changes usually reflect cardiac remodeling.
Left ventricular hypertrophy (50% of patients) [6]
P mitrale
Atrial fibrillation [8]
Signs of right heart strain with P pulmonale in later stages [6] - Chest x-ray
Indications: assess for pulmonary edema, rule out other causes of acute dyspnea
Supportive findings
Decompensated MR and acute MR: signs of pulmonary congestion (see x-ray findings in pulmonary congestion) [5][7]
Acute MR: normal-sized cardiac silhouette [5]
Chronic MR: Changes related to cardiac remodeling and associated heart failure may be visible.
LV enlargement: laterally displaced left cardiac border
LA enlargement: straightening of the left cardiac border and double density sign [22]
Annular calcification may be visible as a C-shaped density. [6] - Additional evaluation
Cardiac MRI (CMR): if both TTE and TEE findings are inconclusive, and for suspected cardiomyopathy or ischemic MR [23]
Stress echo: in ischemic MR and to help assess the need for surgery [24]
CT angiography: in suspected ischemic cardiomyopathy
Coronary angiography: in suspected ischemic MR, prior to surgical intervention
what is the treatment plan for mitral regurg?
All patients with acute primary MR should undergo urgent surgical repair or valve replacement.
While awaiting surgery, any symptoms of heart failure should be managed with medical therapy (e.g., diuretics, nitrates, antihypertensive drugs).
Surgical therapy [5]
Indications
Acute primary MR (urgent surgery)
Acute secondary MR that does not adequately respond to medical therapy
Procedures
Valve repair: preferred option because of the reduced risk of mortality and complications [25]
Valve replacement: may be necessary if there is severe destruction of the mitral valve [7]
Revascularization therapy: in ischemic MR with papillary muscle rupture
All patients with acute primary MR should undergo urgent surgical repair or valve replacement.
Medical therapy
For acute primary MR, medical treatment is usually only a temporizing measure while surgery is planned. The aim is to reduce the symptoms of heart failure and improve forward flow.
Heart failure management:
Vasodilators: to reduce afterload and improve cardiac output
Nitroprusside [6][26]
Nitrates (e.g., nitroglycerin ) [6][27]
Diuretics (e.g., furosemide ): for acute pulmonary edema [28]
Hypotension: inotropes (e.g., dobutamine ) [29]
Atrial fibrillation: consider cardiac resynchronization therapy to improve hemodynamics. [30]
Heart failure treatment may worsen hypotension; use caution in hemodynamically unstable patients.
Bridging devices
Indications
Patients whose symptoms continue to deteriorate despite medical therapy [31]
Unstable patients prior to surgery
Procedures
Intra-aortic balloon pump (IABP) [5][31]
Consider left ventricular assist device (LVAD) or ECMO in patients who are deteriorating despite pharmacological therapy and IABP. [7]
Chronic mitral regurgitation
Management of chronic MR is guided by the symptoms and extent of heart failure and the cause of MR. Medical therapy should be initiated in all patients to optimize cardiac function but surgery is the definitive treatment option.
Medical management
Identify and treat any underlying cause (particularly in secondary MR). [6]
Heart failure management: see “Treatment” in heart failure [6]
Diuretics (e.g., furosemide)
ACE inhibitors (e.g., lisinopril) [6]
Beta blockers (e.g., metoprolol tartrate) [6]
Surgical management and transcatheter mitral repair
Chronic primary MR
Indications [1][9]
Asymptomatic patients with LV dysfunction (LVEF 30–60% or LV end-systolic diameter ≥ 40 mm)
Symptomatic patients with LVEF 30–60 %
Contraindications: Once LVEF is < 30%, surgery is generally not recommended because of the high mortality rate and low likelihood of symptom improvement. [11]
Chronic secondary MR [9] [6]
Indications: consider for patients with severe MR and persistent symptomatic heart failure (NYHA classes III–IV) despite optimal medical management
what is the etiology of mitral valve stenosis?
Most commonly due to rheumatic fever
Autoimmune diseases: systemic lupus erythematosus, rheumatoid arthritis
Congenital
Some conditions may mimic mitral stenosis: bacterial endocarditis of the mitral valve with large vegetation, left atrial myxoma
Degenerative aortic stenosis
Explain the pathophysio of Mitral valve stenosis?
Mitral valve stenosis → obstruction of blood flow into the left ventricle (LV) → limited diastolic filling of the LV (↓ end-diastolic LV volume) → decreased stroke volume → decreased cardiac output (forward heart failure)
Mitral valve stenosis → increase in left atrial pressure → backup of blood into lungs → increased pulmonary capillary pressure → cardiogenic pulmonary edema → pulmonary hypertension → backward heart failure and right ventricular hypertrophy
what are the clinical features of mitral stenosis?
Initially asymptomatic (onset ∼ 10 years after acute rheumatic carditis)
Dyspnea (paroxysmal nocturnal dyspnea) and orthopnea, especially when supine
Hemoptysis
Hoarseness
Dysphagia
Mitral facies
Atrial fibrillation and embolic complications
Later stages: signs and symptoms of right-sided heart failure
how do you diagnose mitral stenosis?
Auscultation (see auscultation in valvular defects)
Diastolic murmur typically heard best at the 5th left intercostal space at the mid-clavicular line (the apex)
Heard loudest when the patient is lying on his/her left side.
Loud first heart sound (S1)
Opening snap of the mitral valve after S2: A high frequency, early-to-mid diastolic sound that occurs when leaflet motion suddenly stops during diastole after the stenosed valve has reached its maximum opening
Shorter interval between S2 and opening snap is indicative of more severe disease, because left atrial pressure is greater than left ventricular end-diastolic pressure (LVEDP).
X-ray chest
Posterior-anterior image
LA enlargement with prominent left auricle (left atrial appendage) → straightening of the left cardiac border
Signs of pulmonary congestion (see “X-ray findings in pulmonary congestion”)
Lateral image
Dorsal displacement of the esophagus (visible in barium swallow test)
Signs of right ventricular hypertrophy
ECG
P mitrale
Atrial fibrillation
Signs of right ventricular hypertrophy (Sokolow-Lyon index)
Echocardiography: most important diagnostic method for detecting and assessing valvular abnormalities
Assess the mitral valve structure, function, and stenosis severity
Leaflet thickening and rigidity
Calcification
Subvalvular thickening
Decreased mitral valve area (MVA): ≤ 1.5 cm2 is considered to be severe MS.
Assess for left atrial thrombus and concomitant mitral regurgitation.
Coronary angiography may be conducted prior to surgical interventions to assess the risk of associated coronary artery disease
what is the treatment of mitral stenosis?
Conservative treatment
Treatment of heart failure: only diuretics may be administered!
Beta blockers or calcium channel blockers: ↓ heart rate and ↓ cardiac output
Endocarditis prophylaxis in high-risk cases e.g., history of IE, prosthetic valve (see “Infective endocarditis”)
Interventional
Indication: severe (MVA ≤ 1.5 cm2) and/or symptomatic mitral stenosis
First-line: percutaneous balloon commissurotomy of the mitral valve (PMBC) if the following criteria are fulfilled:
Favorable valve morphology e.g., no valvulvar calcifications
No left atrial thrombus
No or mild mitral regurgitation
Alternatives: open commissurotomy and surgical valve replacement (mechanical prosthetic valve or biological prosthetic valve)
ACE inhibitors and other afterload-reducing drugs are contraindicated because they cause dilation of peripheral blood vessels, which may lead to cardiovascular decompensation!
what are the complications of mitral stenosis?
Atrial fibrillation → thromboembolic events
Progressive congestion of the lungs, pulmonary edema, pulmonary hypertension
Congestive heart failure
Enlarged left atrium (rare) → esophageal compression, recurrent laryngeal nerve palsy
