1. Acute aortic regurgitation is a medical emergency that can result from conditions like infective endocarditis, aortic dissection, or trauma. 2. It leads to a sudden rise in left ventricular diastolic pressure and fall in cardiac output, often causing profound hypotension and cardiogenic shock. 3. Emergency aortic valve replacement or repair is usually required for severe acute aortic regurgitation, while temporary stabilization measures may be used if surgery faces delay.

1. D . B A S E M E L S A I D E N A N Y
L E C T U R E R O F C A R D I O L O G Y
A I N S H A M S U N I V E R S I T Y
Acute Aortic regurge

2. ETIOLOGY
-Usually a medical emergency cardiogenic shock (no compensatory mechanisms)
-Endocarditis:
valve destruction, leaflet perforation
aortic perivalvular abscess may rupture into the left ventricle, resulting in AR, or into
the left atrium or right ventricular outflow tract, with a clinical presentation that
mimics acute aortic regurgitation.
-Aortic dissection:
Mechanisms:
Dilation of the sinuses with incomplete coaptation of the leaflets at the center of the
valve
involvement of a valve commissure resulting in inadequate leaflet support
Direct extension of the dissection into the base of a leaflet, resulting in a flail valve
leaflet
Prolapse of the dissection flap across the aortic valve into the left ventricular outflow
tract in diastole impeding leaflet closure.
-Rupture of a congenitally fenestrated cusp
-Traumatic rupture of the valve leaflets
-Iatrogenic : aortic balloon valvotomy or a failed surgical valve repair
-Acute mechanical valve regurgitation can be caused by valve thrombosis, IEC

3. PATHOPHYSIOLOGY
--Acute increase in left ventricular diastolic pressure
and a fall in forward cardiac output exacerbated by a
shortening of diastolic filling time {early closure of the
mitral valve (due to high end diastolic pressures) +
tachycardia (caused by a decrease in forward flow and
cardiac output)}.
The net effect is often profound hypotension and
cardiogenic shock.
--Elevated left ventricular end-diastolic pressure leads
to elevated left atrial and pulmonary venous pressures,
which can lead to pulmonary edema

4. CLINICAL PRESENTATION
--Sudden cardiovascular collapse.
--Other presenting symptoms are related to the cause
of acute AR (eg, signs and symptoms of endocarditis or
aortic dissection)

5. Physical examination
--Manifestations of cardiogenic shock  profound
hypotension, pallor, diaphoresis, occasional cyanosis, and
other signs of peripheral vasoconstriction.
--The pulse pressure is normal or may be reduced, but the
pulse is usually weak, thready, and rapid.
--If aortic dissection  inequality of pulses and blood
pressure between the left and right arms may be observed
{may not be appreciated in the setting of profound
hypotension}.
--The cardiac apex is generally not displaced and is not
hyperdynamic.
--peripheral manifestations of chronic AR are less apparent
or may be entirely absent (no wide pulse pressure)

6. Cardiac auscultation
--The early closure of the mitral valve generally produces a soft or
absent S1
--The aortic component of S2 is often soft, while P2 is usually
increased, reflecting pulmonary hypertension.
--An S3 is frequently heard but an S4 is absent.
--In contrast to the high pitched holodiastolic decrescendo murmur of
chronic AR, the murmur with acute AR is a low pitched early diastolic
murmur beginning after S2, may not be heard, especially when the
diastolic gradient between the aorta and left ventricle lessens.
--A systolic murmur resulting from the increased volume of blood
crossing the aortic valve may be heard, but is usually not loud.
--The combination of a soft systolic and a low-pitched diastolic
murmur often produces a "to-and-fro" murmur at the cardiac base in
acute AR.

7. Electrocardiogram
--No specific electrocardiographic changes.
--Nonspecific ST and T wave abnormalities are
common due to the markedly elevated left ventricular
pressures.
--If acute AR is due to aortic dissection, involvement of
the right coronary artery can result in ECG findings of
acute myocardial infarction

8. Chest radiograph
-Pulmonary edema redistribution of blood flow to
the upper lobes and an increase in size and amount of
the pulmonary vasculature
-The cardiac silhouette may be markedly enlarged due
to pericardial effusion
-Widened mediastinum may result from aortic root
dilation

9. Echocardiography
--Diagnostic in acute AR.{TOE more benefits}
--The cause of aortic regurgitation can be determined  aortic valve
endocarditis or aortic dissection
--Severe acute AR is based upon the following findings:
-A vena contracta width (narrowest segment of the color flow jet) >6
mm.
-For central severe jets, the jet width in the left ventricular outflow
tract is large (≥65 percent of the outflow tract width).
-For severe eccentric jets, the visualized jet width is variable.
-A dense continuous wave Doppler signal with a steep diastolic slope
(pressure half-time <200 msec).{rapid equalization of pressure
Ao.,LV}
-The presence of holodiastolic flow reversal in the descending thoracic
and proximal abdominal aorta.
--EF, pericardial effusion

10. Other imaging modalities
--CT imaging may help delineate the anatomy by
identifying the intimal flap, as well as the site and
extent of dissection and the possible involvement of
major branch arteries.
--Usually no time to perform cardiac catheterization or
contrast angiography. Emergency valve surgery should
not be delayed for coronary angiography if there is
severe acute AR with hemodynamic instability

11. TREATMENT
--Emergency aortic valve replacement or repair
--If delay  temporary stabilization : intravenous
vasodilators, such as nitroprusside, and possibly
inotropic agents such as dopamine or dobutamine in
an attempt to enhance forward flow and lower left
ventricular end-diastolic pressure.
--An intraaortic balloon pump is contraindicated
because inflation of the balloon in diastole will worsen
the severity of AR.

12. Acute mild or moderate AR
--Due to an aortic dissection aortic valve
resuspension along with graft replacement of the
ascending aorta often allows preservation of the native
valve with resolution of valve incompetence.
--Due to endocarditis, antibiotic therapy alone may be
sufficient unless the patient has another indication for
valve replacement

13. Thank you