CV Valve Surgery Flashcards
2 types of factors leading to remodeling of myocardium?
mechanical and neurohumoral
3 types of neurohumeral factors leading to remodeling of myocardium?
cytokines, oxidative stress, enzymes
In valvular disease, remodeling is caused by?
overpressure or volume overload
Pressure overload leads to what type of hypertrophy?
concentric
How does ventricular mass increase in concentric hypertrophy?
thickening
Volume overload leads to what type of hypertrophy?
eccentric
How is LV mass increased in eccentric hypertrophy?
increase in volume
Systolic function is dependent on what 3 things?
contractility, afterload, preload
Is contractility dependent on afterload or preload?
not at all
What 2 pressures/volumes make up preload?
diastolic volume + filling pressure
What 2 pressures/volumes make up afterload?
systolic volume + generated pressure
This is the ability of the ventricle to accept incoming flow?
diastolic function
Diastolic function is reliant upon what 2 things?
relaxation + compliance
What is the most common congenital valve disorder?
bicuspid aortic valve resulting in AS
2 other causes of AS?
senile degenerative, rheumatic
People with congenital AS don’t know they have it usually until?
something bad happens like they throw a clot
Most common presenting symptom of AS?
angina on exertion
What is the life expectancy when a person w AS presents with angina on exertion?
5 years
2 other sx of AS?
syncope, CHF
Life expectancy of person with AS when have syncope, when have CHF?
3 years; 1-2 years
Normal AVA?
2.6-3.5 cm
The pressure gradient in AS leads to what type of hypertrophy?
concentric
In AS, diastolic dysfunction with increased LVEDP lead to?
ischemia
What’s a late sign of AS?
eccentric hypertrophy
Another cause of ischemia in AS?
increased transmural volume because of increased area for perfusion and increased LVEDP
Mild, moderate, and severe AS as classified by AVA?
mild AV >1 cm, moderate AV 0.76-1 cm, severe AV
Goal directed intraoperative management of AS?
increased LV preload, slow hr, SINUS RHYTHM, don’t mess w contractility, increased SVR, normal PVR
8 characteristics that an anesthetique technique on a pt w AS should have?
- light premed
- CV surgeon on hand for induction
- narcotic technique for stability of BP
- alpha adrenergic agents for aggressive treatment of low BP
- aggressive tx of arrythmias
- keep HR stable and in sinus
- PA cath (carefully) and TEE
- antegrade and retrograde cardioplegia for best myocardial preservation
2 causes of aortic regurgitation (AR)?
aortic root dilatation or aortic valve disease
4 causes of aortic root dilatation?
degenerative aortic dilation, Marfan’s, syphilitic aortitis, aortic dissection
4 causes of AV valve disease?
rheumatic fever, endocarditis, congenital bicuspid valve, rheumatoid arthritis
Is acute aortic regurg an emergency?
yes
What happens and what are the sx bc of that in acute aortic regurg?
cannot maintain forward flow; sudden and severe dyspnea, CV collapse, rapid deterioration
5 sx of chronic aortic regurg?
SOB, palpitations, fatigue, angina, LV dysfunction
What type of hypertrophy develops in AR?
eccentric bc of volume overload
Does LV systolic or diastolic become overloaded in AR?
both
What happens to LVEDV, LVEDP, SV, and peripheral vasculature in AR?
LVEDV increases slowly, LVEDP remains normal, peripheral vasodilation, initially SV increases
What happens as AR progresses?
coronary perfusion gets poor and irrerversible LV damage is done, LV dysfunction causes increased PA pressures, dyspnea and CHF
What do poor CO and poor coronary perfusion cause?
sympathetic activation, peripheral vasoconstriction, increased afterload
What’s the pathophysiology of acute AR?
sudden increase in LV volume produces increased sympathetic tone, increased contractility, and tachycardia. may not be enough to maintain CO and rapid deterioration occurs, emergency surgery
What does the arterial tracing of AR look like?
wide pulse pressure, rapid upstroke, high systolic peak, low diastolic, bisferiens pulse (two phase pulse caused by backwash)
What is the % of regurg of total LVSV in mild and severe AR?
mild 60%
Goal directed intraoperative management of AR?
increased LV preload, increased hr, normal contractility, decreased SVR, normal PVR
Forward flow in AR is critically dependent on?
keeping preload high; venodilation could severely compromise that
Intraoperative management for AR?
arterial vasodilation beneficial (nipride, NOT nitro), adequately anesthetized for intubation to avoid SNS outflow, PA cath, TEE, IABP contraindicated, may be difficult to separate from bypass and may need preload augmentation
This valve disorder happens twice as often in women?
mitral stenosis
Mitral stenosis is usually secondary to?
rheumatic fever with scarring and fibrosis of the valve edges
What type of decline in functionalty do people with MS have?
slow
5 sx of mitral stenosis?
fatigue, SOB, PND, pulmonary edema, hemoptysis
What arrythmia is common in patients with MS?
afib
Why is hoarseness common in mitral stenosis?
compression of the left recurrent laryngeal nerve by a distended left atrium and enlarged pulmonary artery
Normal MV area?
4-6 cm
Mitral valve area that produces moderate exercise dyspnea?
2.5-2.5 cm
Further progression of MV disease leads to?
increased LA pressures and volume reflected back in to the pulmonary circulation
Mitral valve area that causes increasing sx with mild exercise?
1.5-1 cm
What mitral valve area will you see severe CHF with onset of afib with?
1.5-1 cm
Critical mitral stenosis is below what valve area?
1 cm
Below 1 cm is considered critical mitral stenosis, what pathophysiologic findings result from that?
bordering on CHF constantly, pul HTN, restrictive lung dx, RA congestion, RV failure, interventricular septal shift from dilated RV further impairs filling, tricuspid regurg
What valve issue can mitral stenosis lead to?
tricuspid regurgitation
