Flashcards in Valves (Elves) Deck (50):
What are the major factors that affect flow across any valvular lesion?
- the valve area
- the square root of hydrostatic pressure gradient across the valve
- time duration of transvalvular flow (during systole and diastole)
What are the goals in management of patients with regurgitant lesions?
- decrease or minimize regurgitant flow across mitral or aortic valve
- increase inotropy
- decrease preload
- increase HR (shorten diastolic phase)
** fast, full, forward **
What are the goals in management of patients with stenotic lesions?
- maximize and enhance stenotic flow across the mitral or aortic valve
—> increase HR: want slow squeeze to push more blood through a narrowed valve
What types of valvular lesions can respond to changes in loading conditions?
REGURGITANT lesions (valves) can respond to ∆es in loading conditions—> we want to increase preload and decrease afterload
What types of valvular lesions are generally considered fixed and do not respond to changes in loading conditions?
What are some of the causes of Aortic Stenosis (AS)?
- idiopathic Calcific degeneration
- congenital (bicuspid instead of tricuspid)
- Paget’s Disease (abnormal recycling of bone cells)
- systemic lupus erythmatosus
** normally a chronic condition **
What are some of the presenting symptoms in patients with severe Aortic Stenosis (AS)?
3 classic symptoms- reflect end stage disease
1.) heart failure: dyspnea on exertion, decreased exercise tolerance
2.) syncope: or exertional dizziness
3.) Angina:: or exertional angina
Would you expect to hear a systolic or diastolic murmur with aortic Stenosis?
What pathophysiology would you expect in the patient with severe Aortic Stenosis?
- Severe aortic stenosis causes obstruction of LV outflow, resulting in:
- LV pressure overload
- concentric hypertrophy
- diastolic LV dysfunction with decreased SV and CP
What are some of the reasons that patients with severe aortic stenosis develop cardiac ischemia?
- hypertrophied LV= higher metabolic demand
- increased SBP—> high incidence of concomitant CAD
- prolongation of ejection—> shortens diastolic time, decreases O2 to cardiac muscle
- decrease in myocardial capillary density
What is the single most important hemodynamic goal in managing patients with severe aortic stenosis?
** increases preload to fill non-compliant ventricle
- avoid extremes of HR
- SVR is elevated—> avoid hypotension
What are some of the causes of Aortic Regurgitation?
- rheumatic heart disease
- aortic root dissection, trauma
- connective tissue disorders
- Dexfenfluramine (PhenPhen)
Do patients with aortic regurgitation develop eccentric or concentric hypertrophy?
Eccentric hypertrophy (lumen gets larger)
Would you expect to hear a systolic or diastolic murmur with aortic regurgitation?
Do patients with Aortic Regurgitation develop volume or pressure overloading?
What factors contribute to reduced coronary perfusion pressure in patients with aortic regurgitation?
- increase in myocardial O2 demand because of increased LV mass
* decreased coronary perfusion pressure—>lower DBP, higher LVEDP (widened pulse pressure)
What are some of the symptoms that patients with aortic regurgitation develop?
- CHF/pulmonary edema
How would you manage heart rate and blood pressure in a patient with severe aortic regurgitation?
-HR: increase HR—> decreases diastolic time and decreases regurgitant fraction (80-95bpm)
- BP: increase or maintain preload to maintain forward flow, decrease afterload to improve forward flow
What are some of the causes of mitral stenosis?
- rheumatic fever (women 4xs men)
- rheumatoid arthritis
- systemic lupus erythmetosus
- carcinoid syndrome
What type of a murmur would you expect to hear in a patient with mitral stenosis?
What are the most common presenting symptoms in a patient with severe mitral stenosis?
Asymptomatic for about 20 years, then:
- CHF (50%)
- right HF
What pathophysiology would you expect in the patient with severe Mitral Stenosis?
- chromic obstruction to LA emptying during diastole—> LA volume and pressure overload and structures behind it
- LV chronically under loaded
- LV usually normal- decreased in 1/3 of patients
- RV function normal, but with severe pulmonary HTN—> RV failure and LV function abnoral
What is the single most important hemodynamic goal in managing patients with severe Mitral Stenosis?
HR: decrease Hr to allow ventricle time to fill, prolong diastole
What are some of the causes of mitral regurgitation?
- rheumatic disease
- mitral valve prolapse
- mitral/annular enlargement
- ischemia—> loss of muscle around valve will ∆ how valve functions
- phen phen
What type of murmur would you expect to hear in a patient with mitral regurgitation?
What type of valvular lesion would benefit from IABP?
If a patient with severe mitral regurgitation has a preoccupation LVEF of 35% and undergoes a mitral valve replacement, would you expect to see an increase or decrease in postop LVEF after the valve procedure?
What pathophysiology would you expect in the patient with severe mitral regurgitation?
- LV “unloads” itself into LA (chronic atrial overload)
How would you manage the heart rate and blood pressure in the patient with severe mitral regurgitation?
Fast, full, forward
- HR: increase Hr—> decrease in LV volume, increased forward flow and decrease regurgitant fraction
- contractility: increase or maintain
- SVR: decreasing afterload is helpful
What is hypertrophic cardiomyopathy?
Increase in size and mass of ventricle-most common cause is HTN, 2nd cause is aortic stenosis)
- decreased diastolic compliance
- sub valvular pressure gradient
- ventricular arrhythmias
What are the goals for hypertrophic cardiomyopathy?
- increase preload
- decrease HR
- decrease contractility
What is systolic anterior motion (SAM) of the mitral valve?
When blood is ejected in to LV @ high velocities, Venturi effect is created, which pulls the mitralve valve leaflet towards the anterior septum during systole—> outflow tract obstruction and mitral regurgitation (into RA)
What do you want to avoid in the patient with hypertrophic cardiomyopathy?
Avoid anything that causes decrease in LV volume, such as:
- decreasing preload
- increasing contractility
- decreased afterload
* want to decrease determinants of myocardial O2 consumption as thickened myocardium is predisposed to ischemia
What is a stenotic lesion?
Narrowing of valve orifice caused by thickening and increased rigidity of valve
- valve does not open completely
- hard to squeeze blood past
What is a regurgitant valve?
Incompetent valve- no longer keeps blood flowing unidirectional
- valve doesn’t completely close
Valvular disease can occur secondarily to which diseases?
What s/s will lead you to suspect defective valves?
- decreased exercise capacity
- pulmonary HTN
- edema (pulmonary or systemic)
- blood clots
In a stenotic valve, pressure _____________in the chamber proximal to the valve and _____________ in the chamber or artery distal to the valve.
Aortic stenosis is considered an independent risk factor for what?
Symptomatic patients with out surgical valve replacement have the following life spans:
- syncope: _____
- CHF: ______
-Angina: 5 years
- syncope: 3 years
- CHF: 2 years
* they have compensated for years, no longer working
This is why you should get AVR at the onset of symptoms
LV hypertrophy causes:
When is aortic stenosis considered “critical stenosis”?
When aortic valve area is reduced to 1/4 of its natural size, before significant changes start to occur
What are some consequences of Aortic Regurgitation?
- severe chronic aortic regurgitation causes volume overload of LV with gradually developing eccentric LV dilation
- dilated cardiomyopathy present in advanced stages
- LV failure manifests as progressive decreased EF and CO, increased LA and PA pressures
- severe aortic regurgitation results in low DBP and a wide pulse. Pressure
—> usually well tolerated unless CAD present
Low morbidity during long asymptomatic phase
What is concentric hypertrophy?
Narrowing of chamber and thickening of wall around it
- muscle hypertrophy and decreased volume
What is eccentric hypertrophy?
Dilation and enlargement
- LUMEN elongates relative to muscle mass
Which valvular lesion is use of IABP contraindicated in?
aortic regurgitation—> would increase regurgitation across aortic valve and exacerbate LV dilation
What do you need to do in valvular insufficiency?
Keep it fast, full and moving forward
- keep BP maybe a little low to promote forward flow
What are some consequences of mitral stenosis?
- causes impaired LV function d/t fixed obstruction to LA outflow
- LA, PA, PVR pressures increased
- A fib is common
—> chronic pulmonary HTN and ultimately RV failure
- LV chronically “underloaded”
In mitral regurgitation, volume of regurgitant flow is determined by:
- ventriculo-atrial gradient
- diastolic time
- size of regurgitant orifice