Impact of systemic hypertension on the assessment of aortic stenosis

Abstract

Objective: To determine the effect of systemic arterial hypertension on the indices of aortic stenosis (AS) severity. Methods: A severe supravalvar AS was created in 24 pigs. The maximum and mean pressure gradients across the stenosis were measured by Doppler echocardiography and by catheterisation. Both echocardiography and catheter data were used to calculate stenosis effective orifice area, energy loss coefficient, and peak systolic left ventricular wall stress. Measurements were taken both at normal aortic pressures and during hypertension induced by banding of the distal thoracic aorta in 14 pigs and by intravenous administration of phenylephrine in 10 pigs. Results: During hypertension, systemic arterial resistance downstream from the stenosis increased greatly (all animals: 71 (40)%), whereas total systemic arterial compliance decreased significantly (238 (21)%). Hypertension resulted in a moderate increase in effective orifice area (29 (14)%) and energy loss coefficient (25 (17)%) and substantial decreases in catheter gradients (maximum: 240 (20)%; mean: 243 (20)%; peak to peak: 270 (23)%) and Doppler gradients (maximum: 235 (17)%; mean: 237 (16)%). In multivariate analysis, peak to peak gradient was significantly (p , 0.001) related to the energy loss coefficient, mean flow rate, and arterial compliance, whereas maximum and mean catheter gradients were related only to the energy loss coefficient and flow rate. Of major importance, maximum systolic left ventricular wall stress increased greatly during hypertension (43 (23)%). Conclusions: The severity of AS may be partially masked by the presence of coexisting hypertension. The markers of AS severity should thus be interpreted with caution in hypertensive patients and be re-evaluated when the patient is in a normotensive state.

Impact of Vascular Hemodynamics on Aortic Stenosis Evaluation: New Insights Into the Pathophysiology of Normal Flow—Small Aortic Valve Area—Low Gradient Pattern

“…rAC is a major contributor to the development of systolic hypertension, contributing to LV afterload and decreased coronary flow during diastole, and it has been shown to be a strong predictor of LV dysfunction and adverse events 30, 31, 32, 33, 34. Patients with AS already have increased LV afterload because of valvular stenosis, and it has been demonstrated that rAC has a significant additive effect and contributes to LV dysfunction and occurrence of adverse outcomes 22, 35. In the present study, we showed that rAC induces a marked reduction in MG and V peak for any AS severity, even if flow is stable and even in the absence of hypertension.…”

“…The decrease in flow induced by hypertension leads to a reduction in transvalvular gradient and velocity. Kadem et al previously demonstrated in an animal model of supravalvular AS that acute hypertension induces a significant reduction in the peak and mean gradients as measured by catheter without significant decrease in mean transvalvular flow rate 22. In our animal study, the induction of hypertension resulted in a slight decrease in stroke volume but did not influence significantly the mean transvalvular flow rate.…”

“…A lateral right thoracotomy was performed and fourth and fifth right ribs were removed. In each sheep, a severe (AVA <0.6 cm 2 ) and a critical (AVA <0.4 cm 2 ) supravalvular AS were induced by a ligature around the aorta about 0.5 cm downstream to the aortic valve annulus 21, 22. Central arterial hypertension of 130 mm Hg of systolic blood pressure was induced by banding of the distal ascending aorta while normal systolic blood pressure was 90 mm Hg in anesthetized sheep.…”

Impacto da hipertensão arterial no remodelamento ventricular, em pacientes com estenose aórtica

“…Finally, it is worth emphasizing that the severity of aortic stenosis may be masked by the coexistence of hypertension (underestimated valve gradient); thus, the degree of AoS should be interpreted with caution when blood pressure is high and should be reassessed after the normalization of pressure 21 . Thus, despite the classic contraindication for patients with severe AoS, antihypertensive drugs should be considered when treating these patients when hypertension is associated with AoS.…”

Cardiac surgery and hypertension: a dangerous association that must be well known

“…Hypertension can be present in 68% of patients with severe aortic stenosis [51]. In severe supravalvar aortic stenosis model, systemic arterial hypertension may result in significant impairement of the aortic compliance [52]. A study based on 3.39 million discharges in Ireland revealed that the prevalence of hypertension was 21.0% in the patients with aortic stenosis, and was 1.1% in those with aortic stenosis.…”