Systemic hypertension in low-gradient severe aortic stenosis with preserved ejection fraction

Area of Science:

• Cardiology
• Cardiovascular Medicine
• Hypertension Research

Background:

• Low-gradient severe aortic stenosis with preserved ejection fraction is increasingly recognized.
• Systemic hypertension often coexists, potentially causing elevated left ventricular (LV) filling pressures and dyspnea.

Purpose of the Study:

• To investigate the hemodynamic effects of vasodilator therapy in patients with low-gradient severe aortic stenosis, preserved ejection fraction, and coexisting hypertension.
• To assess the impact of reducing systemic afterload on LV filling pressures and pulmonary hypertension in this specific patient cohort.

Main Methods:

• Invasive hemodynamic catheterization was performed on symptomatic patients with hypertension and low-gradient severe aortic stenosis (aortic systolic pressure >140 mm Hg, mean gradient <40 mm Hg, ejection fraction >50%).
• Intravenous sodium nitroprusside was administered to reduce blood pressure and arterial afterload.
• Hemodynamic parameters including aortic systolic pressure, mean pulmonary artery pressure, LV end-diastolic pressure, aortic valve area, and mean gradient were measured before and after nitroprusside infusion.

Main Results:

• Baseline hemodynamics revealed severe hypertension, pulmonary hypertension, elevated LV end-diastolic pressure, and reduced stroke volume.
• Nitroprusside infusion significantly reduced all measures of afterload, including mean pulmonary artery pressure and LV end-diastolic pressure (P<0.001).
• Aortic valve area and mean gradient also showed significant improvement with nitroprusside therapy (P=0.001 and P=0.02, respectively).

Conclusions:

• Systemic hypertension in this patient group is linked to elevated LV filling pressures and pulmonary hypertension.
• Vasodilator therapy effectively lowers total LV afterload, leading to decreased LV filling pressures and pulmonary artery pressures.
• These findings offer crucial insights for managing patients with low-gradient severe aortic stenosis, preserved ejection fraction, and hypertension.