Diagnosis and Management of Aortic Valve Stenosis: The Role of Non-Invasive Imaging

Figures

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  Figure 1. (A) Recording of the peak velocity through a stenotic aortic valve in the apical five-chamber view by continuous-wave Doppler. (B) Recording of the peak velocity through Left ventricular outflow tract in the apical three-chamber view by pulse-wave Doppler. The images were executed with Philips EPIQ 7 (Philips Medical System, Bothell, WA, USA).

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  Figure 2. Measurement of the diameter of the Left ventricular outflow (yellow line) from the parasternal long-axis view, during systole, directly below the base of the aortic leaflets, and from the internal surfaces of the interventricular septum and the posterior aortic wall.

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  Figure 3. The figure shows the case of valve with pseudo-severe aortic stenosis (A) at low (rest) and normal flow rate (dobutamine) and that of valve with truly severe aortic stenosis (B) at low and normal flow rate. SV: stroke volume; AVA: aortic valve area; TPG: transvalvular pressure gradient. DBX: Dobutamine. See the text for details. A projected AVA ≤ 1 cm2 is considered severe. In many ways, the concept of projected AVA outperforms the traditional flow-reserve concept, which may be intrinsically flawed due to the complex interaction between decreased contractility, increased afterload and altered geometry in classical LF-LG AS [38]. However, many patients with paradoxical LF-LG AS have small ventricles, with concentric remodeling and a high prevalence of atrial fibrillation and isolated upper septal hypertrophy, which may lead to serious side effects such as LVOT dynamic obstruction with hypotension and syncope; thus, DSE should be stopped as soon as increase in flow is sufficient.

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  Figure 4. Measurement of aortic valve calcifications on representative images. (A) Low dose chest CT scan image focused on the aortic valve of an 86-year-old woman with low-flow low-gradient aortic stenosis and 9000 Agatston score. (B) In white color number in Hounsfield Units (HU) to quantify aortic valvular calcium on contrast-enhanced scans. Here, equal to 1000 HU. Courtesy of Marianna Adamo.

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  Figure 5. Stepwise integrated approach for the assessment of discordant grading aortic stenosis. AS: aortic stenosis; AVA: Aortic valve area; LVEF: Left ventricular ejection fraction; SVi: stroke volume index to body surface area; DSE: dobutamine stress echocardiography; AVA proj: projected area at standardized normal flow rate of 250 mL/s. AVA proj ≤ 1 cm2 is considered severe; CT-AVC: computed tomography aortic valve calcium scoring (severity cut-offs: women ≥ 1200 AU and men ≥ 2000 AU); ** AVA proj and CT-AVC are used because the stenosis severity often remains indeterminate at the outset of DSE, or echocardiographic assessments are discordant.

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  Figure 6. Current recommendation from European and American guidelines for aortic valve replacement in aortic stenosis. AVR: Aortic Valve Replacement. AS: Aortic Stenosis. DSE: Dobutamine Stress Echocardiography. SAVR: Surgical aortic valve replacement. TAVI: Transcatheter aortic valve replacement. ACC/AHA: American College of Cardiology/American Heart Association. AVA: Aortic valve area. BSA: Body Surface Area. TC-AVC: computed tomography aortic valve calcium scoring. LVEF: left ventricular ejection fraction. PAsP: Pulmonary artery systolic pressure. ETT: exercise treadmill test BP: blood pressure.