Howard J. Sachs, MDAssociate Professor of Medicine

University of Massachusetts Medical Schoolwww.12DaysinMarch.com

E-mail: Howard@12daysinmarch.com

Aortic (Insufficiency) Regurgitationfor the USMLE Step One Exam

the Sounds: #9

LSB

Ao

Diastolic

MS

Apex

Snap

LSB

Ao

Diastolic

LSB

Ao

Diastolic

Aortic Regurgitation: the Curriculum

• Background• Physiology Consequences (→ EDV)

– Pulse pressure• Aorta: limited compliance (C = V/P)

– Eccentric hypertrophy– Hemodynamic curves (cardiac cycle, pressure-volume loop)

• Physical Exam: the Murmur– Chronic AI: Decrescendo at mid-LSB

• Squatting maneuver → intensity

• Demographics– Endocarditis– Rheumatic fever, acute– Aortitis/Dissection

Aortic Regurgitation: the Curriculum

• Background• Physiologic Consequences (→ EDV)

– Pulse pressure• Aorta: limited compliance (C = V/P)

– Eccentric hypertrophy– Hemodynamic curves (cardiac cycle, pressure-volume loop)

• Physical Exam: the Murmur– Chronic AI: Decrescendo at mid-LSB

• Squatting maneuver → intensity

• Demographics– Endocarditis– Rheumatic fever, acute– Aortitis/Dissection

VolumeOverload

Aortic Regurgitation: the Curriculum

• Background• Physiologic Consequences (→ EDV)

– Pulse pressure• Aorta: limited compliance (C = V/P)

– Eccentric hypertrophy– Hemodynamic curves (cardiac cycle, pressure-volume loop)

• Physical Exam: the Murmur– Chronic AI: Decrescendo at mid-LSB

• Squatting maneuver → intensity

• Demographics– Endocarditis– Rheumatic fever, acute– Aortitis/Dissection

VolumeOverload

Why does the Pulse Pressure (Systolic – Diastolic) widen?[normal = <50 mm Hg)

SYSTOLIC: Increased EDV (LA + Regurg Vol) → SV DIASTOLIC: Regurgitant Volume

This is a key pathophysiologic hallmark

Why does the Pulse Pressure (Systolic – Diastolic) widen?

SYSTOLIC: Increased EDV (LA + Regurg Vol) → SV DIASTOLIC: Regurgitant Volume

Main contributor

Why does the Pulse Pressure (Systolic – Diastolic) widen?

SYSTOLIC: Increased EDV (LA + Regurg Vol) → SV DIASTOLIC: Regurgitant Volume

Stroke Volume

Why does the Pulse Pressure (Systolic – Diastolic) widen?

SYSTOLIC: Increased EDV (LA + Regurg Vol) → SV DIASTOLIC: Regurgitant Volume

Main contributor

Stroke Volume → Systolic pressure as the aorta has a finite capacity (i.e. limited compliance) to accommodate the volume.

Aorta, Fixed Capacity (limited compliance)

Stroke Volume → Systolic pressure as the aorta has a finite capacity (i.e. limited compliance) to accommodate the volume.

If you raise the volume against fixed compliance, the pressure must also rise

Aorta, Fixed Capacity (limited compliance)

Stroke Volume → Systolic pressure as the aorta has a finite capacity (i.e. limited compliance) to accommodate the volume.

Stroke Volume

Aorta, Fixed Capacity (limited compliance)

If you raise the volume against fixed compliance, the pressure must also rise

Stroke Volume → Systolic pressure as the aorta has a finite capacity (i.e. limited compliance) to accommodate the volume.

Stroke Volume → Systolic pressure as the aorta has a finite capacity (i.e. limited compliance) to accommodate the volume.

This is also observed in anemia.

Decreased oxygen delivery → vasodilation → afterload → SV

Result: Widened pulse pressure

Aortic Regurgitation: the Curriculum

• Background• Physiologic Consequences (→ EDV)

– Pulse pressure• Aorta: limited compliance (C = V/P)

– Eccentric hypertrophy– Hemodynamic curves (cardiac cycle, pressure-volume loop)

• Physical Exam: the Murmur– Chronic AI: Decrescendo at mid-LSB

• Squatting maneuver → intensity

• Demographics– Endocarditis– Rheumatic fever, acute– Aortitis/Dissection

VolumeOverload

Volume overloadEccentric hypertrophyDilated (chamber) CM

EDV

Volume overloadEccentric hypertrophyDilated (chamber) CM

Pressure overloadConcentric LVH

Hypertrophic (wall) CM

EDV

Physiologic Purpose: Wall Stress (= P X r/2h)

Physiologic Purpose:Starling Force

Pressure ( Afterload):Aortic Stenosis

Volume ( EDV):Aortic Insufficiency

Concentric Hypertrophy Eccentric Hypertrophy

Pressure ( Afterload):Aortic Stenosis

Volume ( EDV):Aortic Insufficiency

Longer (Starling forces)

Thicker

Aortic Regurgitation: Hemodynamics I

AV Close

IsovolRelax

IsovolCont

AV Open

Rapideject

Rapidfilling

MV Open

MV Close

120

80

10

Which portion of the curve is effected by AI?

Peak murmur intensity?

??

Aortic Regurgitation: Hemodynamics I

IsovolRelax

AV Open

Rapideject

Rapidfilling

MV Open

MV Close

120

80

10

The aortic pressure curve reveals higher systolic pressure and lowerdiastolic pressure (reflecting the widened pulse pressure).

AI is more commonly and physiologically represented by the LV pressure-volume loop.

160

60

Aortic PressureCurve

AV doesn’t close

Aortic Regurgitation, Aorta

Aortic Stenosis, Delay

Mitral Regurgitation, LA, Sys

Mitral Stenosis, LA, A2:O2

Aortic Regurgitation: Hemodynamics I

IsovolRelax

AV Open

Rapideject

Rapidfilling

MV Open

MV Close

120

80

10

The aortic pressure curve reveals higher systolic pressure and lower diastolic pressure (reflecting the widened pulse pressure).

AI is more commonly and physiologically represented by the LV pressure-volume loop.

160

60

Aortic PressureCurve

AV doesn’t close

Pressure

Volume

Low Hg, Hi Vol

IsovolumetricContraction

IsovolumetricRelaxation

AoOpen

AoClose

Rapid ejectionESV

MVOpen

Rapid Filling MVClose

StrokeVolume

Hemodynamics II: LV Pressure-Volume Curve

EDV

Pressure

Volume

IsovolumetricContraction

IsovolumetricRelaxation

AoOpen

AoClose

Rapid ejectionESV

MVOpen

Rapid Filling MVClose

StrokeVolume

We should be able to construct the AI curve (consider the regurgitant volume)?

Pressure

IsovolumetricRelaxation

AoOpen

AoClose

MVOpen

Rapid Filling MV Closed

We should be able to construct the AI curve –(parameters related to the regurgitant volume)

• EDV• Pulse Pressure → Stroke Volume• ESV

EDV

Volume

Pressure

IsovolumetricRelaxation

AoClose

MVOpen

Rapid Filling MV Closed

We should be able to construct the AI curve –(parameters related to the regurgitant volume)

• EDV• Pulse Pressure → Stroke Volume• ESV

EDV

Volume

ESV AoOpen

Aortic Regurgitation: Hemodynamics II

Pressure

AoClose

MVOpen

Rapid Filling

StrokeVolume

We should be able to construct the AI curve –(parameters related to the regurgitant volume)

• EDV• Stroke Volume• ESV

MV Closed

EDV

Volume

ESV AoOpen

Aortic Regurgitation: Hemodynamics II

Pressure

Volume

AoClose

MVOpen

Rapid Filling MVClose

StrokeVolume

Increased Preload

The increased stroke volume distinguishes this from a dilated CM

which can also have increase EDV

↑ESV

We should be able to construct the AI curve –(parameters related to the regurgitant volume)

• EDV• Stroke Volume• ESV

Pressure

StrokeVolume

Increased Preload (EDV)

Dilated Cardiomyopathy:Increased EDVDecreased SV

AI

DCM

Aortic Regurgitation: the Curriculum

• Background• Physiology Consequences (→ EDV)

– Pulse pressure• Aorta: limited compliance (C = V/P)

– Eccentric hypertrophy– Hemodynamic curves (cardiac cycle, pressure-volume loop)

• Physical Exam: the Murmur– Chronic AI: Decrescendo at mid-LSB

• Squatting maneuver → intensity

• Demographics– Endocarditis– Rheumatic fever, acute– Aortitis/Dissection

Aortic Valve Disorders

Regurgitation

170

WidenedPulse

Pressure

60Diastolic

LSBWide pulse pressure

Diff Dx (LSB):HCMVSD Systolic

Second relevant diastolic murmur (other: mitral stenosis)

AINo opening snap.

Wide pulse pressure.Different location.

Different hemodynamics.Different constellation of derivatives.

Only overlap: Rheum Fever BUT AI is an early manifestation...PLUS: one other treat…

Aortic Valve Disorders

Regurgitation

170

WidenedPulse

Pressure

Austin Flint murmur

Rumbling sound here

Apical, rumbling diastolic murmur

Aortic Valve Disorders

Regurgitation

170

WidenedPulse

Pressure

60

Heard after S2 → decrescendo

AI: No opening snap

How will you recognize the AI patients?Demographic Settings:

Endocarditis

Dilated Aortic Root

Aortitis (Syphilis, Ank Spond, TA)Dissection (HTN, EDS, Marfan’s)

Acute RF

Ehlers-Danlos

Dissection with Intimal Flap

How will you recognize the AI patients?Demographic Settings:

Widened Pulse PressureHead bob - deMusset’sWater hammer (fem pulse, felt)Pistol shot (fem pulse, heard)Quincke’s (finger capillary pulsation)

Pulse Pressure

Bonus AI Thoughts (3):

Fast A fib?

These patients arepreload dependent.

Would not tolerate fast a fib; inadequate ventricular filling.

Bonus AI Thoughts (3):

Inotropy?Chronotropy?

Preload?Afterload?

Just like MR, improve the

forward fraction

Rx AI?

Ehlers-Danlos

Dissection with Intimal Flap

Bonus AI Thoughts (3):

Acute AI

Chronic AI

Aortic Regurgitation: the Curriculum

• Background• Physiology Consequences (→ EDV)

– Pulse pressure• Aorta: limited compliance (C = V/P)

– Eccentric hypertrophy– Hemodynamic curves (cardiac cycle, pressure-volume loop)

• Physical Exam: the Murmur– Chronic AI: Decrescendo at mid-LSB

• Squatting maneuver → intensity

• Demographics– Endocarditis– Rheumatic fever, acute– Aortitis/Dissection

Howard J. Sachs, MDAssociate Professor of Medicine

University of Massachusetts Medical Schoolwww.12DaysinMarch.com

E-mail: Howard@12daysinmarch.com

Aortic Insufficiency for the USMLE Step One Exam

Aortic Valve:

Take it off your bucket list!