P054: EFFECTS OF CARDIAC AUSCULTATION THROUGH CLOTHING IN AORTIC STENOSIS PATIENTS AND CORRELATION WITH ECHOCARDIOGRAPHY.
Delaney LaGrew, MS, Joseph LaGrew, MD, Junito Abrigo, Nik Gravenstein, MD; University of Florida Department of Anesthesia
Introduction: Aortic stenosis has traditionally been diagnosed by auscultation and echocardiogram with severity based on aortic valve area, peak velocity, and mean pressure gradient.1 Findings on cardiac auscultation have been shown to correlate with echocardiogram for patients with aortic stenosis.2
This retrospective cohort study evaluates the effect of listening through an item of clothing versus directly over the skin on quantitative auscultation magnitude.
Methods: After IRB approval and informed consent 17 patients presenting with a previous diagnosis of aortic stenosis had their heart sounds recorded as previously described.3 A Littmann model 3200 electronic stethoscope (3M Health Care, St. Paul, MN) was placed on four spots: right and left 2nd intercostal space, left lower sternal border and left 5th intercostal space (mid-axillary line), directly on skin and then over their clothing or hospital gown in the sitting position. Aortic valve area (AVA) as measured on the most recent echocardiogram was recorded in cm2. Demographic information, comorbid diseases, other echo findings and mean electronically auscultated murmur amplitudes were recorded. Correlations between murmur magnitude and AVA, mean gradient and peak gradient were done in the aortic position on skin, through clothing and with the area of loudest magnitude.
Results: The effect of listening through clothing vs over skin was found to be equivalent (64.1 compared to 63.2, p = 0.713). There was no significant correlation between aortic valve area and murmur magnitude auscultated directly over skin or through clothing (p = 0.21 and 0.68). Secondary outcomes show a significant inverse relationship between mean gradient and peak gradient and murmur magnitude on skin (p = 0.022 and 0.0436) but not through clothing (p=0.5101 and 0.7426). There was no correlation between any of the echo findings and the loudest area of the murmur. Additionally, the murmur was best heard in many patients in the aortic area (7/17) however in a significant number of patients (6/17) the aortic stenosis murmurs were loudest auscultated over the left lower sternal border.
Conclusion: Our findings reinforce some well-known tenets of cardiac auscultation as well as provide new insight. Listening through a layer of clothing is equivalent in amplitude to listening over clothing for patients with aortic stenosis. However, there was a significant difference in the correlation with both mean and peak velocities, with only skin findings having a significant correlation to these values. The location of auscultation impacts exam findings and aortic stenosis murmurs may not be heard best over the traditional right parasternal aortic area in all patients. The inverse correlation The lack of correlation between valve area and mean amplitude reinforces the value of echocardiography. Larger cohorts should be targeted in the future to confirm these findings.