That’s how one of the patient presented to our hospital . An echo documented severe aortic stenosis with a peak aortic gradient of 80mmhg and a bounding systolic blood pressure of 180 mmhg . Is that an exception ?
I recall the early days of medical school when we are fervently taught that systolic blood pressure is primarily determined by stroke volume and LV contractility .
The above example clearly proves this is explicitly wrong .
Now , we understand systolic blood pressure have many determinants . Stroke volume is just one of them .
The tone , distensibility of major blood vessels arising from aorta determine how a pressure wave is going to get amplified .
If you say stroke volume is not major determinate of systolic blood pressure . . . . does it imply , the antique bed side cardiac sign Pulsus parvus et- tardus a myth ?
No , it still holds good . But it is not a hard sign . We realise now , a patient with a well felt carotid can have a severe Aortic stenosis .
- Pre- existing systemic hypertension is a valid explanation.
- The other popular explanation for loss of systolic decapitation due to associated aortic regurgitation may be acceptable . (Not really proven though ! )
What will be the central aortic pressure in critical Aortic stenosis ?
It is definitely lower than brachial cuff pressure .This will explain the systolic blood pressure is actually an amplified signal .
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Dr.S.Venkatesan MD 