valvular heart disease Flashcards
what is a normal aortic valve area ?
3-4 cm2
when do symptoms occur in aortic stenosis?
when valve area is 1/4th of normal
what are the three types of aortic stenosis?
Supravalvular
Subvalvular
Valvular
describe the pathophysiology of aortic stenosis
-A pressure gradient develops between the left ventricle and the aorta. (increased afterload)
-LV function initially maintained by compensatory pressure hypertrophy
-When compensatory mechanisms exhausted, LV function declines.
describe the presentation of aortic stenosis
-Syncope: (exertional) 15%
-Angina: (increased myocardial oxygen demand; demand/supply mismatch) 35%
-Dyspnoea: on exertion due to heart failure (systolic and diastolic) 50%
-Sudden death <2%
what are the physical signs of valvular heart disease?
- slow rising carotid pulse and decreased pulse amplitude
- heart sounds- soft or absent second sound, s5 gallop due to LVH
- ejection systolic murmur- crescendo- decrescendo character
- loudness does not tell you anything about severity
what does the onset of treatment show?
The onset of symptoms is an indication of poor prognosis if left untreated.
how do you investigate valvular heart disease?
Echocardiography
what are the two measurements obtained from an echocardiogram
Left ventricular size and function: LVH, Dilation, and EF
Doppler derived gradient and valve area (AVA)
describe the AVA of mild aortic stenosis
> 1.5 cm 2
describe the AVA of moderate aortic stenosis
1.0-1.5 cm2
describe the AVA of severe aortic stenosis
< 1.0 cm 2
what is the general management of AS?
Fastidious dental hygiene / care- small risk of infection going into blood stream
Consider IE prophylaxis in dental procedures
what is the medical management of AS?
limited role since AS is a mechanical problem.
Vasodilators are relatively contraindicated in severe AS
what is the aortic valve replacement management of AS?
Surgical
TAVI – Transcatheter Aortic Valve Implantation
what are the indications for intervention before it gets too severe in aortic stenosis?
Any SYMPTOMATIC patient with severe AS (includes symptoms with exercise)
Any patient with decreasing EF
Any patient undergoing CABG with moderate or severe AS
Consider intervention if adverse features on exercise testing in asymptomatic patients with severe AS
define chronic mitral regurgitation
Backflow of blood from the LV to the LA during systole
Mild (physiological) MR is seen in 80% of normal individuals.
what are the aetiologies of chronic mitral regurgitation ( causes)?
Primary causes ( disease of leaflets- not enough tissue)
1. Myxomatous degeneration (MVP)
2. Ischemic MR
3. Rheumatic heart disease
4.Infective Endocarditis
secondary causes ( normal valve architecture but impaired closure due to abnormal LV/LA geometry)
1. dilated cardiomyopathy
describe the pathophysiology of MR
pure volume overload
compensatory mechanisms
describe the pathophysiology of mitral regurgitation compensatory mechanisms
Left atrial enlargement, LVH and increased contractility
Progressive left atrial dilation and right ventricular dysfunction due to pulmonary hypertension.
Progressive left ventricular volume overload leads to dilatation and progressive heart failure.
what are the physical signs and symptoms of mitral regurgitation?
- Auscultation
- exertion dyspnoea ( exercise intolerance)
- heart failure
what are the physical signs and symptoms of mitral regurgitation- describe auscultation?
-pansystolic murmur at the apex radiating to the axilla
-S3 (CHF/LA overload)
-In chronic MR, the intensity of the murmur does correlate with the severity.
-Displaced hyperdynamic apex beat
what investigations take place in MR
ECG:
CXR:
ECHO:
what may an ECG in MR show?
May show, LA enlargement, atrial fibrillation and LV hypertrophy with severe MR
what may an CXR in MR show?
LA enlargement, central pulmonary artery enlargement.
what may an ECHO in MR show?
Estimation of LA, LV size and function. Valve structure assessment
TOE v helpful
What medications are used to manage MR?
-Rate control for atrial fibrillation with -blockers, CCB, digoxin
-Anticoagulation in atrial fibrillation and flutter
-Nitrates / Diuretics in acute MR
-Chronic HF Rx if chronic MR with CCF
-No indication for ‘prophylactic’ vasodilators such as ACEI, hydralazine
how often does does someone with mild MR do serial echocardiography?
2-3 years
how often does does someone with moderate MR do serial echocardiography?
1-2 years
how often does does someone with severe MR do serial echocardiography?
6-12 months
IE prophylaxis
Patients with prosthetic valves or a Hx of IE for dental procedures
what are the indications for surgery in severe MR?
-ANY Symptoms at rest or exercise (repair if feasible)
-Asymptomatic:
–If EF <60%, LVESD >40mm
–If new onset atrial fibrillation/raised PAP >50 mmHg
define arortic regurgitation
Leakage of blood into LV during diastole due to ineffective coaptation of the aortic cusps
what is the etiology of chronic aortic regurgitation? ( causes)
Bicuspid aortic valve
Rheumatic
Infective endocarditis
describe the pathophysiology of AR
Combined pressure AND volume overload
Compensatory Mechanisms: LV dilation, LVH. Progressive dilation leads to heart failure
What are the physical exam findings of Aortic Regurgitation ?
wide pulse pressure- most sensitive
Hyperdynamic and displaced apical impulse
- auscultation
What are the physical exam findings of Aortic Regurgitation - auscultations?
-Diastolic blowing murmur at the left sternal border
-Austin flint murmur (apex): Regurgitant jet impinges on anterior MVL causing it to vibrate
-Systolic ejection murmur: due to increased flow across the aortic valve
what the natural progression of aortic regurgitation?
Asymptomatic until 4th or 5th decade
Rate of Progression: 4-6% per year
Progressive Symptoms include:
- Dyspnoea: exertional, orthopnea, and paroxsymal nocturnal dyspnea
Palpitations: due to increased force of contraction and ectopics
what will you find on a CXR with someone who has AR?
enlarged cardiac silhouette and aortic root enlargement
what will you find on a ECHO with someone who has AR?
Evaluation of the AV and aortic root with measurements of LV dimensions and function (cornerstone for decision making and follow up evaluation)
How is aortic regurgitation managed ?- generally
consider IE prophylaxis
How is aortic regurgitation managed ?- medically
Vasodilators (ACEI’s potentially improve stroke volume and reduce regurgitation but indicated only in CCF or HTN
what is used to monitor AR?
serial echocardiograms
other management ways of ar
Surgical Treatment: Definitive Tx
(TAVI in exceptional cases only if unsuitable for SAVR)
what is the indication for surgery in AR?
ANY Symptoms at rest or exercise
Asymptomatic treatment if:
EF drops below 50% or LV becomes dilated > 50mm at end systole
Define mitral stenosis
Obstruction of LV inflow that prevents proper filling during diastole
what is a norma MV AREA?
4-6 cm2
What is the most predominant cause of mitral stenosis?
Rheumatic carditis
where do Transmitral gradients and symptoms begin in mitral stenosis?
at areas less than 2 cm2
describe the prevalence and incidence of mitral stenosis?
decreasing due to a reduction of rheumatic heart disease.
what is the etiology of mitral stenosis?
Rheumatic heart disease: 77-99% of all cases
Infective endocarditis: 3.3%
Mitral annular calcification: 2.7%
describe the MS pathophysiology
Progressive Dyspnea (70%): LA dilation —->pulmonary congestion (reduced emptying)
worse with exercise, fever, tachycardia, and pregnancy
Increased Transmitral Pressures: Leads to left atrial enlargement and atrial fibrillation.
Right heart failure symptoms: due to Pulmonary venous HTN
Hemoptysis: due to rupture of bronchial vessels due to elevated pulmonary pressure
describe the natural progression of MS
Disease of plateaus:
Mild MS: 10 years after initial RHD insult
Moderate: 10 years later
Severe: 10 years later
what is death by MS most likely due?
Due to progressive pulmonary congestion, infection, and thromboembolism.
what are the physical signs of MS?
prominent “a” wave in jugular venous pulsations: Due to pulmonary hypertension and right ventricular hypertrophy
Signs of right-sided heart failure: in advanced disease
Mitral facies: When MS is severe and the cardiac output is diminished, there is vasoconstriction, resulting in pinkish-purple patches on the cheeks
describe the heart sounds in MS
Diastolic murmur:
-Low-pitched diastolic rumble most prominent at the apex.
-Heard best with the patient lying on the left side in held expiration
-Intensity of the diastolic murmur does not correlate with the severity of the stenosis
what would an ECG show in MS?
may show atrial fibrillation and LA enlargement
what would an CXR show in MS?
LA enlargement and pulmonary congestion. Occasionally calcified MV
what would an ECHO show in MS?
The GOLD STANDARD for diagnosis. Asses mitral valve mobility, gradient and mitral valve area
How is MS managed?s
serial echocardiogaphy
medications
How is MS managed?- serial echocardiography
Mild: 3-5 years
Moderate:1-2 years
Severe: yearly
How is MS managed?- medications
MS like AS is a mechanical problem and medical therapy does not prevent progression
-blockers, CCBs, Digoxin which control heart rate and hence prolong diastole for improved diastolic filling
Duiretics for fluid overload
how is MS managed?
Identify patient early who might benefit from percutaneous mitral balloon valvotomy.
IE prophylaxis: Patients with prosthetic valves or a Hx of IE for dental procedures.
what are the indications for mitral valve replacement?
ANY SYMPTOMATIC Patient with NYHA Class III or IV Symptoms
Asymptomatic moderate or Severe MS with a pliable valve suitable for PMBV
