Abstract 666: Inconsistent Grading of Aortic Valve Stenosis by Current Guidelines: Results of Hemodynamic Catheter Studies in Patients With Apparently Normal Left Ventricular Function
Background: On echocardiography approximately one third of patients with severe aortic valve stenosis based on aortic valve area (AVA <1.0cm2) demonstrate a mean pressure gradient (ΔPm) in the non-severe range (≤40mmHg) despite apparently normal left ventricular function. It has been suggested that inconsistent echocardiographic grading may be due to “paradoxical”low stroke volume. However, the correct echocardiographic assessment of stroke volume hinges on the often problematic measurement of the left ventricular outflow tract (LVOT) diameter. We therefore set out to investigate whether inconsistent grading and reduced stroke volume persist when the quantification of aortic valve stenosis is based on cardiac catheterization which is independent of LVOT measurements.
Methods and results: From our database a total of 333 consecutive patients were identified who underwent cardiac catheterization within 30 days after their index echocardiography showing an AVA ≤2cm2 and shortening fraction ≥30%. On invasive testing 85 patients (25%) demonstrated inconsistent (AVA<1cm2 and ΔPm≤40mmHg) and 153 (46%) consistent grading (AVA<1cm2 and ΔPm>40mmHg) with the remainder (29%) presenting with a calculated AVA≥1cm2. Inconsistently graded patients were older (71 vs. 67 years, p<0.006) with no differences in sex or body surface area (BSA) between groups. Stroke volume and stroke volume index were significantly lower in inconsistently graded patients (63±14 vs. 71±15mls and 35±7 vs. 39±7mls, both p<0.001). However, 48% of inconsistently graded patients had a normal stroke volume index >35mls.
Conclusion: In the framework of current guidelines inconsistent grading of aortic valve stenosis is frequent, extends to cardiac catheterization, and is only partially explained by low stroke volume despite apparently normal left ventricular systolic function.