Severe aortic stenosis will cut off the systolic BP and hence classical pulsus parvus et tardus occurs. This is what , we have been taught all along.
How for it is true?
One thing is clear from clinical observation. Systolic BP need not be low, often its normal even in severe Aortic stenosis. The issue becomes curious when high BP is associated with severe Aortic stenosis. This can happen by a variety of mechanisms.(Aging/Loss of Aortic elasticity /Pressure recovery/Hypertension) I think, there have been little correlative studies of pulsus parvus with central aortic pressure.
Can Aortic stenosis be a cause for systolic Hypertension? (This academically murky question rose after I stumbled upon this paper )
This paper from the journal of Human Hypertension which was published many decades ago.It sincerely documented high BP in spite of severe AS . The most crucial aspect of this study , however, was the fact that hypertension was completely corrected after Aortic valve replacement. The authors attributed to this high systolic BP as the transmission of LV chamber pressure. This is a frontal attack on the traditional concept of pulsus parvus and systolic decapitation in LVOT obstruction.
I am not sure, whether knowledge always breeds knowledge. Medical science is equally affected by new-onset Ignorance or not recognizing past knowledge.( Like this paper of 1996.) I think this study is done with a good scientific basis and unable to find any serious flaws. Hats of to the authors. This could lead to a further breakthrough in our understanding of transvalvular gradients in Aortic stenosis and the poorly understood vascular- valvular Interactions. With, catheter-based TAVRs become so common, we can exactly measure the pressure dynamics in the Aortic root pre and post valve replacement. (* My take is , systolic BP in severe Aortic stenosis is preserved until the onset of LV dysfunction)
Reference
Dr.S.Venkatesan MD 