Nagelhout Chp 25 - CV Flashcards
What is normal aortic valve area
2.5 - 3.5 cm2
What is aortic stenosis and what are the causes :
Normal area is 2.5 - 3.5 cm2 . Reduction of 1/3 to 1/2 of the valve area means stenosis.
The narrowing results in obstruction of blood flow into the aorta .
Causes : 1) degeneration and calcification of the leaflets or
2) presence of bicuspid instead of tricuspid valve .
Patient with aortic regurgitation , how will you select muscle relaxant for the patient ?
Goal in aortic regurgitation is to 1) maintain normal to elevates HR . Pancuronium/ vagolytic good choice . But the potential for sux to cause bradycardia should be considered before administration.
What are the main anesthetic goal for patient with aortic regurgitation ?
HR : Normal to high with NSR
Preload : normal to high
Afterload : decreased
AVOID myocardial depression
Describe the difference between ACUTE and CHRONIC aortic regurgitation and
Acute : LV has no time to compensate for increase in LV volume = LV failure, Pulmonary edema , CV collapse may ensue .
Chronic : no s/s shown for a long time , during normal activity the symptoms are not incapacitating . As long as the mitral valve patience does not result from LVH , pulmonary circulation is preserved. End stage AR = myocardial failure, decreased CO , high elevation in LVEDV and pulmonary edema
What valve area and transvalular gradient is considered to be AS( Aortic Stenosis ) ?
N
Normal SVR
800 to 1500 dynes/sec/cm5
Normal Pulmonary vascular resistance is
50 to 150 dynes/sec/cm5
What is severe aortic stenosis ?
Valve area less than 0.8 cm2
And transvalvular gradient > 50 mmHg
What does increase DBP cause to AR?
Increases the backward pressure gradient which results in an increase in the proportion of SV that regurgitates back into the left ventricle
MC conditions affecting the aortic leaflets that result in AR ?
Rheumatic Fever
Bicuspid aortic valve
Infective endocarditis
Use of anorexigenic ( diet ) drugs
What is AR?
Failure of the aortic valve leaflet to velodrome properly due to disease of the aortic root or of the leaflets themselves
Why is Afib or a junction alone rhythm so detrimental to a patient with aortic stenosis?
There is DECREASED pressure gradient between the LA and the LV bc of the aortic stenosis , and the atrial kick is needed to achieve adequate LV filling. Afib and Junctional rhythms knock out that extra 20 30 % that is needed and results in CHF and hypotension
How is CO affected with aortic stenosis ?
At rest = CO is normal
Exertion = heart cannot increase CO = angina and dyspnea , even though there is no CAD
How is myocardial oxygen and demand affected by aortic stenosis ?
The demand is INCREASED bc of concentric ventricular hypertrophy and
The supppy is DECREASED bc of intramyicardial vessels during systole restricts arterial flow to the myocardium.
75% of patients with aortic stenosis die within
3 years if valve not replaced
S/S of severe aortic stenosis
Classic triad :
Angina , Syncope , CHF
Aortic regurgitation medical management ?
Reduce Afterload = reduce transvalvular gradient = easy forward flow out of LV => Hydralazine and nifedipine .
If acute exacerbation : Nitroprusside or Dobutamine can be used
Patient has mild mitral stenosis, what will the heart do to compensate in order to maintain a good SV ? What factors can cause this compensation not to occur ?
The left atrial pressure will increase in an attempt to increase blood flow through the narrow valve .
If tachycardia or Afib the increase in atrial pressure will not work and will not be able to maintain the SV
Mitral regurgitation vs Mitral stenosis .what are the goals for each ? How are they similar ?
MR = Increase HR and decrease afterload
MS= normal or decreased HR and normal afterload
In both: NSR, Maintain preload normal to increased levels , AVOID increase in PVR
What meds are good for Mitral Regurgitation?
Ace I, BB, biventricular pacemaker
Mitral regurgitation , what do you see in the PAOP waveform
A large V wave , the changes in the V wave amplitude help estimate changes int he degree of mitral regurgitation
What Heart sound in Mitral regurgitation ?
Holosystolic Murmur radiating to the axilla
Mitral regurgitation , when to do surgery ?
When EF is greater than 60 % or if patient is symptomatic
How does SVR affect the pressure gradient in Mitral regurgitation?
Low SVR = decrease in regurgitant volume
High SVR = worse regurgitant volume
What 3 factors determine the regurgitant volunteer in Mitral regurgitation ?
1) size of valve
2) HR
3) pressure gradient across valve
What is the main problem in Mitral regurgitation?
Decrease in forward flow of blood ( SV) bc the volume is moving backwards into the left atrium during systole . ( holosystolic murmur )
MCC of acute Mitral regurgitation?(5)
1) MI
2) Papillary muscle dysfunction
3) Chordae Tendinae rupture
4) Trauma to chest
5) Infectious endocarditis
Primary anesthetic management objectives for patient with mitral stenosis ?
AVOID : hypovolemia , excessive Tberg = pulmonary edema
N2O : be careful = it can increase PVR ( which we want to avoid )
Drugs causing tachycardia = Ketamine, Pancuronium is a no no, or be careful !
Meperidine can cause tachycardia only opioid that can do it :) otherwise give OPIODS to prevent intraop tachycardia , or increase depth of anesthesia or give a Beta Blocker
Give phenylephrine or vasopressin if hypotension since they do not increase the HR
Epidural is preferred over spinal bc … less decrease in sympathetic activity with epidural !
What is normal mitral valve area and when does symptoms occur ?
Normal is 4-6 cm2
Symptoms when less than 1.5cm2
How can mitral valve stenosis result in pulmonary edema ?
LA pressure increase»_space; transmitted into the pulmonary vasculature»_space; Pulmonary venous pressure > 25mmHg= leak into pulmonary interstitial space»_space; decreased pulmonary compliance»_space; increased Work of Breathing ( WOB )
Heart sound in Mitral valve prolapse (MVP)?
Midsystolic click and a late systolic murmur
How are LA, Pulmonary vasculature and RV affected by Mitral stenosis ?
Mitral valve small» LA pressure increase > pulmonary blood volume and pressure increase»_space; right ventricular afterload increase» RV hypertrophied and fails
How is LV volume affected by mitral stenosis ?
Valve opening decreases» pressure gradient across valve increases» flow of blood through he opening decreases»_space;LV volume decreases .
What cardiac conditions develop from Mitral stenosis ?
CHF
Pulmonary HTN
RV hypertrophy
Mitral Stenosis is higher in ____. Over a period of 20 to 30 years ____cause the mitral valve leaflets to thicken , the commisure may fuse, the leaflets and annulus may become calcified.
Higher in female
Over 20 to 30 years , Rheumatic Fever
MCC of Mitral Stenosis
Rheumatic Fever
MC symptoms of valvular disorders in general ?
1) CHF
2) Dysrhythmia
3) Syncope
4) Angina
What is mixed valvular disorder ?
It is a combination of stenosis , and insufficiency. One usually more dominant than the other
Heart sound in Mitral Stenosis ?
Opening Snap in early diastole and
Rumbling diastolic murmur heard best at the axilla or apex
What are the risk factors for developing aortic stenosis ?
Simalar to those factors for Ischemic Heart Disease :
HTN , HLD, DM, Smoking, and male gender
What is a the anesthetic choice in Mitral regurgitation .
1) Neuraxial is NOT contraindicated BUT : dramatic decrease in sympathetic activity = consider that super low bp may happen
General anesthesia is the anesthetic of choice .
MVP is
When 1 or both mitral leaflets dip into the the left atrium during systole . It can occur with or without Mitral regurgitation.
What factors decrease the degree of prolapse in MVP ?
Any factor that maintain a LARGER ventricular volume = decrease degree of prolapse .
HTN , Vasoconstriction, drug induced myocardial depression, increased preload = decrease degree of prolapse
Never thought HTN could be good for something in the heart *
What factors will increase the prolapse ?
The more the ventricle empties the more the prolapse :
Increase LV contractility or decrease SVR = worse prolapse !
S/S of MVP
Although many are asymptotic:
1) chest pain
2) MR
3) Infectious endocarditis
4) embolism
5) even sudden cardiac death
What disorders exhibit high indidence of MVP?
Marfan Lupus Rheumatic carditis Thyrotoxicosis Myocarditis
MVP is more common in
Young females
S1 happens then
Ventricular pressures are greater than Atrial pressures , closing the tricuspid and mitral valves
SVR is the
Load that the cardiac muscles of the ventricle encounter after contracting starts
What is Eisenmeger’s syndrome ?
Is a reversal of the left-to-right intracardiac shunt due to increase in the pulmonary vascular resistance.
Once the PVR = or > than SVR the shunts reverses to a right-to-left shunt.
Medical treatment of PDAs
Indomethacin ( a nonselective cycloogenase Inhibitor) is the first line therapy
