Aortic Regurgitation Flashcards
What are some causes of chronic aortic regurgitation?
Congenital bicuspid deformation
Associated diseases: Marfan’s, connective tissue disease, etc
Rheumatic fever
What kinds of things cause acute aortic regurgitation?
Endocarditis
Trauma
Aneurysm dissection
What are they symptoms associated with aortic regurgitation?
Diastolic murmur
Decreased DBP
What is the magnitude of regurgitation influenced by?
HR
SVR
Forward flow with AR is?
decreased net forward flow
How is regurgitation classified?
By the regurgitant fraction of SV
What is the regurgitant fraction of mild AR?
Under 40%
What is the regurgitant fraction for severe AR?
Over 60%
What are the secondary compensation mechanisms with AR?
Increased blood volume
Eccentric ventricular hypertrophy
What is eccentric hypertrophy?
Decrease in wall thickness
Increase in chamber size
What occurs due to the compensation associated with AR?
Ventricular compliance increases because there is an increase in volume
What ultimately occurs from years of AR?
LV failure > now LVEDP does increase > pulmonary edema
Describe chronic vs acute AR
With chronic AR ventricle has time to hypertrophy and dilate for long term compensation that can eventually lead to LV failure.
With acute AR there is sudden LV overload without time for compensation and immediate LV failure is likely
Describe myocardial oxygen supply and demand with AR
Demand is increased due to increased mass
Supply is decreased because the lower DBP decreases CPP
What is the HR anesthetic goal?
Modest increase in HR
-this allows less time for diastolic regurgitation
What is the proload goal with AR?
Maintain or increase preload
What is the SVR goal with AR?
Decrease SVR
-less resistance promotes forward flow
What is the contractile goal with AR?
Maintain contractility
-keeps volume moving forward
What anesthetic technique is more manageable with AR?
General
Induction drugs with AR?
Any
-ketamine will increase HR (good), but also increase SVR (bad)
Muscle relaxants with AR?
Any
Pancuronium may increase HR (good)
Volatile anesthetic with AR?
Isoflurane is the ideal
-strongest vasodilator (good)
-modest increase in HR (good)
SEVO and DES are good too
What with anesthesia will increase the likelihood of LV failure with AR?
Myocardial depression
-agents
Increased afterload
-vasoconstriction
How should you treat LV failure and increasing LVEDP with AR?
Reduce afterload with Nipride
-arterial dilator
If that’s not enough Inotropes
-Dobutamine
How could a PAC help monitor a pt with AR?
Adequate preload is essential to maintain net forward volume
Too much vasodilation risks preload reduction
Helps find optimal filling pressure
In general which aortic disease leads to more hemodynamic changes?
Stenosis
Monitoring AR during anesthesia
5 lead EKG
-ischemia risk
PAC (+/-)
-monitor preload, optimal filling pressure
