Invasive Hemodynamic Exercise Response in Hemodynamically Significant Aortic Stenosis With Preserved Left Ventricular...

Area of Science:

• Cardiology
• Hemodynamics
• Aortic Stenosis

Background:

• Guidelines suggest discordant low-gradient (LG) aortic stenosis (AS) can be severe, but assessment is challenging.
• Right heart catheterization during exercise is the gold standard for evaluating ventricular hemodynamics.
• No prior invasive studies compared exercise hemodynamic responses in discordant LG AS versus severe AS.

Purpose of the Study:

• To describe exercise hemodynamics in patients with asymptomatic discordant AS and preserved left ventricular ejection fraction (≥50%).

Main Methods:

• 86 patients with aortic valve area ≤1.5 cm² underwent right heart catheterization at rest and during maximal exercise.
• Key measurements included pulmonary capillary wedge pressure (PCWP) and cardiac output (CO), calculating the PCWP/CO-slope.
• Patients were stratified into discordant LG AS, moderate AS, and high-gradient (HG) severe AS groups.

Main Results:

• The PCWP/CO-slope was significantly steeper in discordant LG AS (3.3) and HG severe AS (2.7) compared to moderate AS (1.9).
• Systemic arterial compliance and AS severity were associated with the PCWP/CO-slope in a regression model.
• Discordant LG AS patients showed a leftward-upward shift in the PCWP/CO-curve.

Conclusions:

• Discordant LG AS and HG severe AS demonstrate similar exercise hemodynamic responses, indicating discordant LG AS is a severe form of AS.
• The observed leftward-upward shift in the PCWP/CO-curve for discordant LG AS suggests co-existing heart failure with preserved ejection fraction physiology.