Aortic Valve Flashcards
Views of the aortic valve
ME AV SAX
•NCC nearest IAS
•RCC near origin of RCA
•LCC near origin of LCA
ME AV LAX
•RCC in far field
•NCC or LCC in near field
•measure LVOT, annulus, SoV, STJ, Asc Aorta
Deep TG LAX
•alignment of doppler beam parallel to blood flow
•calculate CO and AVA by continuity equation
•determine dimensionless index
TG LAX
ME 5C
Pathophysiology of aortic insufficiency
No isovolumetric phases
Higher EDVs and ESVs
EDP elevated in acute and decreases in chronic
Heart compensates by dilating and increases SV
Volume overload problem that compensates by dilating which eventually leads to chronic uncompensated when overdilated
LV functional adaptations in AI
Acute —> increased pressure and volume
Chronic compensated —> dilation with increased SV with decreased RF
Chronic uncompensated —> overly dilated with decreased SV and increased RF
TEE evaluation of AI
AI jet / LVOT diameter (ME AV LAX) •>65% AI area / LVOT area (ME AV SAX) •>60% Jet depth (ME AV LAX) •papillary muscle Vena contracta (ME AV LAX, ME AV SAX) •>6mm width •>7.5 mm^2 area Slope of AR jet decay (Deep TG LAX, TG LAX) •>3 m/s Pressure Half Time •<200 ms •affected by multiple things — not the best or most reliable measure Holodiastolic flow reversal descending thoracic aorta Regurgitant volume •>60 mL Regurgitant fraction •>50%
Prognosis of AI dependent on 3 factors
High Risk = definite surgery
Symptomatic
LV dysfunction (EF < 55%)
LV dilation (LVESD > 25 mm/m^2)
Dilation of ascending aorta
•sinus of valsalva measurement the best predictor (normal 25 - 31 mm)
•dilation > 50 - 55 mm replace regardless of level of AI
Low Risk Group Ao ratio < 1.3 (measured / predicted sinus diameter — determined by age and size of patient) •> 40 yo : 1.92+(0.74 x BSA) •18-40yo: 0.97+(1.12 x BSA) Annual rate of change < 5%
When should AV be replaced for AI?
Severe symptomatic AR
Asymptomatic with: •severe chronic AR w/o aneurysm of the ascending aorta with: LV ESD/BSA > 25 mm/m^2 EDD > 70 mm or Resting LVEF < 55%
Chronic AR with aortic root dilation
Aortic insufficiency classification
Type 1a — dilation of ascending aorta Type 1b — dilation of annulus and SoV Type 1c — dilation of annulus Type 1d — perforation Type 2 — prolapse Type 3 — restriction
Pathophysiology of aortic stenosis
Pressure overload problem
During LV ejection there is a significant amount of pressure generated
LVEDP is also elevated
TEE Evaluation of AS
Peak velocity •> 4 m/s Mean pressure gradient •> 50 mmHg •best gradient to measure Max pressure gradient •> 70 mmHg Dimensionless Index — VTI lvot / VTI av •< 0.25 •independent of patient size, no measuring LVOT radius •Vpeak can be substituted for VTI AVA •< 1 cm^2 A/BSA •< 0.6 cm^2/m^2 **for low gradient / low flow AS use the continuity equation or dimensionless index**
Pressure Recovery re: AS
Peak instantaneous gradient with doppler > peak to peak gradient with catheterization
•overestimates the pressure gradient across the valve
