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When transaortic pressure measurements are made during catheterization, the phenomenon of pressure recovery-a higher pressure in the aorta distal to the valve than in the valve orifice itself-may create confusion if not recognized because Doppler measures the gradient at the orifice level. In patients undergoing transcatheter aortic valve replacement (TAVR), multimodality imaging includes CT assessment of aortic annulus size and shape, leaflet length, and the annular to coronary ostial distance.ĭiagnostic cardiac catheterization is rarely needed for adults with AS but should be considered when echocardiographic and other noninvasive data are nondiagnostic or when there are discrepancies between noninvasive findings and other clinical data. CMR is also valuable for assessing aortic root and ascending aortic anatomy in patients with a bicuspid valve.Ĭomputed tomography (CT) imaging provides an alternate approach for planimetry of valve area and provides quantitative measures of valve calcification. CMR can distinguish between bicuspid or trileaflet valve anatomy and provide accurate assessment of peak jet velocity. Direct planimetry of AVA is sometimes possible, particularly with transesophageal or 3D imaging, but overall accuracy of this approach is limited due to the nonplanar anatomy of the stenotic valve and to calcification-related acoustic shadowing and reverberations.Ĭardiac magnetic resonance (CMR) imaging is useful when echocardiographic data are suboptimal or conflicting with clinical assessment of AS severity. A normal ratio is close to 1.0 with a ratio of 0.25 indicating a valve area 25% of normal. Instead, the ratio of LV outflow to aortic velocity may be useful because this ratio is, in effect, indexed to the patient's own LV outflow tract size. However, indexing AVA to body size may not be appropriate in overweight or obese patients. Some clinicians index AVA to body size to account for expected smaller valve areas in smaller patients. However, with a low transaortic flow rate, severe AS might be missed if only velocity or pressure gradient data are considered. In patients with mixed stenosis and regurgitation, the diagnosis of severe valve disease will be evident based on a high transaortic gradient. 8, 10 AVA calculation is especially important when transaortic volume flow rate is higher than normal (as with coexisting aortic regurgitation) or lower than normal (as with LV dysfunction or a small normally functioning left ventricle) because transaortic velocities and gradients vary with volume flow rate. Echocardiographic ΔP mean and AVA calculations have been well validated against invasive measurements and are now the clinical standard of care. Standard measures of AS severity are the maximum velocity (V max) across the stenotic valve, the mean transaortic pressure gradient (ΔP mean) calculated with the Bernoulli equation, and the functional aortic valve area (AVA), calculated with the continuity equation ( Table 1 and Figure 1). Transcatheter AVR is now available for patients with severe comorbidities, is recommended in patients who are deemed inoperable and is a reasonable alternative to surgical AVR in high risk patients. Bioprosthetic valves are recommended for patients over the age of 65 years. However, in most patients with severe symptoms, AVR is lifesaving. Poor outcomes after AVR are associated with low-flow low-gradient AS, severe ventricular fibrosis, oxygen dependent lung disease, frailty, advanced renal dysfunction and a high comorbidity score. In symptomatic patients, AVR improves symptoms, improves survival and, in patients with LV dysfunction, improves systolic function. The onset of symptoms portends a predictably high mortality rate unless AVR is performed. In asymptomatic patients, markers of disease progression include the degree of leaflet calcification, hemodynamic severity of stenosis, adverse LV remodeling, reduced LV longitudinal strain, myocardial fibrosis and pulmonary hypertension. Echocardiography is the primary diagnostic approach to define valve anatomy, measure AS severity and evaluate the left ventricular (LV) response to chronic pressure overload. Calcific aortic stenosis (AS) is a progressive disease with no effective medical therapy that ultimately requires aortic valve replacement (AVR) for severe valve obstruction.