J Cardiovasc Ultrasound.  2012 Jun;20(2):79-84. 10.4250/jcu.2012.20.2.79.

Impact of Afterload on the Assessment of Severity of Aortic Stenosis

• Chang SA
• Kim HK
• Sohn DW

• KMID: 2177370
• DOI: http://doi.org/10.4250/jcu.2012.20.2.79

Abstract

BACKGROUND
Aortic stenosis (AS) is increasingly diagnosed in current aging society. Echocardiography is the most important tool in the assessment of AS and its severity. However, load-dependency of Doppler measurement could affect the accuracy of AS severity assessment. We tried to evaluate the impact of afterload on the assessment of AS severity by modification of afterload using pneumatic compression (Pcom).
METHODS
Forty patients diagnosed as moderate or severe AS [effective orifice area of aortic valve (EOAAV) by continuity equation of < 1.5 cm2] were consecutively enrolled. Patients with severely uncontrolled hypertension, severe left ventricular (LV) dysfunction, and other significant valve disease were excluded. Comprehensive echocardiography was performed at baseline to assess AS severity. Then, pneumatic compression of the lower extremities by 100 mmHg was applied to increase LV afterload. After 3 minutes, echocardiography was repeated to assess AS severity.
RESULTS
Mean blood pressure was significantly increased under Pcom (p < 0.001), while heart rate remained unchanged. Peak aortic valve velocity (Vmax) was slightly, but significantly decreased under Pcom (p = 0.03). However, Doppler velocity index and EOAAV by continuity equation were not affected by Pcom.
CONCLUSION
AS severity assessment by echocardiography was not dependent on the change of LV afterload imposed by Pcom. AV Vmax was slightly decreased with LV afterload increment, but these changes were too small to alter treatment plan of AS patients. EOAAV and Doppler velocity index are more stable parameters for AS severity assessment.

Keyword

Aortic stenosis; Echocardiography; Afterload

MeSH Terms

Aging
Aortic Valve
Aortic Valve Stenosis
Blood Pressure
Echocardiography
Heart Rate
Humans
Hypertension
Lower Extremity

Figure

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  Fig. 1 Hemodynamic changes after pneumatic compression. Mean blood pressure was increased after pneumatic compression and systemic vascular resistance and systemic arterial compliance were also significantly increase; however heart rate was not changed.

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  Fig. 2 Change of Doppler parameter after pneumatic compression. TVGpeak and TVPGmean were increased after pneumatic compression. On the other hand, Doppler index (TVILVOT/TVIAV) and calculated EOA did not change. TVILVOT: time velocity integral of Doppler at LV outflow tract, TVIAV: time velocity integral of trans-aortic valvular Doppler, EOA: effective orifice area, AV Vmax: aortic valve maximal systolic velocity, AVA: aortic valve area.

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