Role of Multimodal Cardiac Imaging in Low-Flow, Low-Gradient Aortic Stenosis


Severe aortic stenosis (AS) is defined as a mean transvalvular aortic gradient (MG) $40 mm Hg or a peak aortic jet velocity (aortic Vmax) $4.0 m/sec, and an aortic valve area (AVA) ≤1.0 cm2.1 However, >40% of patients with AS have a discordance between MG and AVA,2the most frequent cause being the presence of a stenosis with small AVA, low MG and low peak velocity. The main objective of the present clinical case is to present the multimodal approach used in a patient with paradoxical low-flow, low-gradient (PLF-LG) AS (MG < 40 mm Hg, AVA ≤1.0 cm2 , left ventricular ejection fraction [LVEF] 50%, and stroke volume [SV] index < 35 mL/m2 ).


An 88-year-old man with a medical history of permanent atrial fibrillation, dual-chamber pacemaker placement for degenerative conduction system disease, group 3 pulmonary hypertension (obstructive sleep apnea syndrome and chronic obstructive pulmonary disease), and chronic kidney disease (Kidney Disease: Improving Global Outcomes stage IIIb) presented to our emergency department with 2 weeks of fatigue, dyspnea, and progressive lower extremity edema.

On physical examination, blood pressure was 100/60 mm Hg, pulse was 80 beats/min; respiratory rate was 30 breaths/min, and oxygen saturation was 84%. Cardiac auscultation revealed arrhythmic cardiac sounds with a first sound of variable intensity, a second sound with IIP reinforcement, and an ejection murmur in aortic area III/VI with Gallavardin’s phenomenon in the apex. The lung fields presented bilateral infrascapular crackling rales and bilateral pleural effusion; the patient had a globular abdomen with ascites and edema of the lower extremities.

Electrocardiography indicated that the patient had atrial fibrillation with ventricular paced rhythm and left bundle branch block (Figure 1). Laboratory investigations revealed high sensitivity troponin I of 83 ng/mL (normal range, 0-15 ng/mL), N-terminal pro–brain natriuretic peptide of 3,764 pg/mL (normal range, 0-125 ng/mL), hemoglobin of 11.8 g/dL, a leukocyte count of 8,100 per mL, a platelet count of 191,000 per mL, glucose of 118.4 mg/dL, creatinine of 2.25 mg/dL, blood urea nitrogen of 60.4 mg/dL, C-reactive protein of 3.43 mg/dL, and procalcitonin of 0.16 ng/dL.


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