Morning Report: Acute Aortic Regurgitation

Acute Aortic Regurgitation

AR: diastolic flow of blood from the aorta into the LV

Epidemiology: prevalence in U.S ranges from 2-30%, but on 5-10% have severe disease

Predisposed in:

bicuspid valve (2% of males)
Marfan, syphilis, Ehlers-Danlos Syndrome, giant cell, Takayasu, ankylosing spondylitis

Etiology:

Endocarditis: causes valve destruction and leaflet perforation.
- In addition, aortic perivalvular abscess may rupture into the LV causing AR
Aortic Dissection: can cause AR by dilating the sinuses with incomplete coaptation of the leaflets, involve the valveor leaflet, or the diessection flap can prolapse across the valve.
- should always suspect acute AR if AR with chest or back pain
Rupture of a congenitally fenestrated cusp
Traumatic rupture of the valve leaflets: can occur after deceleration injury or blunt trauma.
Iatrogenic: aortic balloon valvotomy or transcatheter aortic valve replacement (TAVR).
Rheumatic fever (used to be most common cause of chronic AR)

Single center review of 268 adults referred for AV replacement (18% had acute AR)

Bioprosthetic valves:

Pathophysiology:

in chronic AR, the volume overload of the LV is associated with a gradual increase in LV size so that it maintains a normal foward CO despite the regurgitant valve flow
- LV diastolic pressures remain normal
in acute AR, the regurgitant volume fills a small ventricle that has not had time to dilate
- causes an acute increase in LV diastolic pressure and a fall in forward CO, causing pulmonary edema

Severe acute AR presents with sudden cardiovascular collapse and pulmonary edema.

Chronic AR causes increased pulse pressure, causes Corrigan’s pulse (rapid upstroke and collapse of the carotid artery pulse)

Physical Exam: Findings can be very subtle, therefore often mistaken for other acute conditions like non-valvular heart failure, PNA, or sepsis.

shock
nml pulse pressure with weak thready arterial pulse
- difference is because the LV stroke volume is not increased
low pitched diastolic murmur beginning after S2
- may not be heard
a systolic murmur from increased volume of blood crossing the AV may be heard
can cause a low pitched “to-and-fro” murmur at the base of the heart

Treatment: Emergency AV replacement or repair

IV vasodilator like nitroprusside or nitroglycerin
inotropic agent such as dobutamine
- goal is to enhance forward flow and lower LV end diastolic pressure
if due to aortic dissection higher target HR (>60) may be required

Sources

Wang SS. (2/12/2014). Aortic Regurictation. Medscape. Retrieved 4/25/15 from http://emedicine.medscape.com/article/150490-overview.
Otto CM. (4/22/2015). Acute Aortic Regurgitation in Adults. UpTpDate. Retrieved 4/25/15 from http://www.uptodate.com/contents/acute-aortic-regurgitation-in-adults#H1
Morganroth J, Perloff JK, Zeldis SM, Dunkman WB. Acute Severe Aortic Regurgication, pathophysiology, clinical recognition, and management. Annals of Internal Medicine 87: 223-232, August 1977.