Double loaded LV in degenerative aortic stenosis with hypertension

Double loaded LV in degenerative aortic stenosis with hypertension

Usually systolic pressures are low in significant aortic stenosis. But hypertension can be associated as an independent condition in elderly with degenerative calcific aortic stenosis. In fact, hypertension can be present in as many as one third of elderly with aortic stenosis. Presence of hypertension may alter the physical findings of aortic stenosis. The carotid upstroke may be prominent, unlike in usual aortic stenosis. The murmur intensity may be diminished and the second heart sound can be near normal.

The presence of hypertension makes the left ventricle a double loaded chamber with valvular obstruction and vascular resistance presenting dual loads. The valvuloaortic impedance measures the global load to the left ventricle due to aortic stenosis and hypertension. Dual loads increase the systolic stress of the left ventricle [1]. The valvular pressure gradient is taken as the intrinsic systolic load and systemic blood pressure the extrinsic load on the left ventricle. Vascular biomechanics may modify the quantification of severity of aortic stenosis due to this dual load.

But the exact magnitude, clinical significance and diagnostic implications of this interaction between the vascular and valvar loads are not well known. A porcine study conducted by Kadem et al showed that severity of aortic stenosis may be partially masked by coexisting hypertension [2].

References

1. J Bermejo. The Effects of Hypertension on Aortic Valve Stenosis. Heart. 2005 Mar;91(3):280-2.
2. L Kadem, J G Dumesnil, R Rieu, L-G Durand, D Garcia, P Pibarot. Impact of Systemic Hypertension on the Assessment of Aortic Stenosis. Heart. 2005 Mar;91(3):354-61.