Clinical Challenges in Accurate Assessment of Severe Aortic Stenosis With a Special Focus on Low-Gradient Aortic Stenosis and Normal Ejection Fraction

Abstract

Aortic stenosis (AS) is one of the most common valvular disorders affecting the aging US population. Although guidelines published by leading cardiac societies outline diagnostic and management strategies for this condition, in daily practice clinicians face dilemmas when trying to confirm the diagnosis of severe AS because of discrepancies in quantitative parameters obtained by echocardiography and cardiac catheterization. More recently, a low-gradient variant of severe AS has been increasingly recognized in the setting of normal ejection fraction. This review focuses on the current clinical challenges of AS diagnosis with a special focus on paradoxical low-flow low-gradient AS in the setting of preserved ejection fraction. We evaluate all aspects of AS quantitation in reference to paradoxical low flow aortic stenosis and discuss newer parameters which may help the clinician reconcile some of the discrepancies of this less understood condition.

Identification of Factors that Predict whether the Right Parasternal View Is Required for Accurate Evaluation of Aortic Stenosis Severity

“…More than moderate AS was defined as an AVA (by the continuity equation) <1.5 cm 2 , a peak aortic velocity (AV Vmax) >3 m/sec, or a mean transaortic pressure gradient (AV mean PG) >25 mmHg. 16 And stroke volume index (SVi) of total patients (n = 263) was more than 35 mL/m 2 . Exclusion criteria included previous AVR, other concomitant moderate or severe valvular disease, previous cardiac surgery, or poor echocardiography images.…”

“…In total, 263 patients with more than moderate AS who had undergone comprehensive echocardiography were enrolled between January 2006 and May 2014. More than moderate AS was defined as an AVA (by the continuity equation) <1.5 cm 2 , a peak aortic velocity (AV Vmax) >3 m/sec, or a mean transaortic pressure gradient (AV mean PG) >25 mmHg . And stroke volume index (SVi) of total patients (n = 263) was more than 35 mL/m 2 .…”

Effects of increased left ventricular wall thickness on the myocardium in severe aortic stenosis with normal left ventricular ejection fraction: Two‐ and three‐dimensional multilayer speckle tracking echocardiography

“…Forty‐five participants with severe AS patients and age‐, sex‐matched normal healthy controls that had undergone echocardiography were enrolled between September 2011 and June 2014. Severe AS was defined as aortic valve area (AVA; by the continuity equation) <1.0 cm 2 , peak aortic velocity (AV Vmax) >4 m/s or a mean transaortic pressure gradient (AV mean PG) >40 mm Hg . Previous study used the criteria of LVH in severe AS as below: Increased LV wall thickness was defined as septal thickness >1.0 cm or posterior wall thickness >1.0 cm .…”

“…Severe AS was defined as aortic valve area (AVA; by the continuity equation) <1.0 cm 2 , peak aortic velocity (AV Vmax) >4 m/s or a mean transaortic pressure gradient (AV mean PG) >40 mm Hg. 10 Previous study used the criteria of LVH in severe AS as below: Increased LV wall thickness was defined as septal thickness >1.0 cm or posterior wall thickness >1.0 cm. 11 The following were used as exclusion criteria: previous aortic valve replacement (AVR), concomitant other valvular disease of moderate or severe severity, arrhythmia (atrial fibrillation, RBBB, LBBB), chronic renal failure (CRF), LVEF <55%, coronary artery disease defined as >50% narrowing in at least one coronary artery in an angiogram, history of myocardial infarction, acute coronary syndrome, previously performed coronary artery bypass surgery, or percutaneous coronary intervention.…”

Natural Progression of Low-Gradient Severe Aortic Stenosis with Preserved Ejection Fraction

“…These results appear not to be an anomaly arising from the misreading of echocardiographic measure-ments. [13][14][15][16][17] This group, known as Low-Gradient Severe AS with preserved LVEF (LGAS), can differ from Low-Flow, Low-Gradient Severe AS patients (AVA <1 cm 2 , MG <40 mmHg, and reduced LVEF ≤0.50), who are known to have a poor prognosis. 18,19 In this latter group, the low gradient is attributed to low cardiac output caused by systolic dysfunction.…”