The complex nature of discordant severe calcified aortic valve disease grading: new insights from combined Doppler echocardiographic and computed tomographic study.
OBJECTIVE
With concomitant Doppler echocardiography and multidetector computed tomography (MDCT) measuring aortic valve calcification (AVC) load, this study aimed at defining: 1) independent physiologic/structural determinants of aortic valve area (AVA)/mean gradient (MG) relationship; 2) AVC thresholds best associated with severe aortic stenosis (AS); and 3) whether, in AS with discordant MG, severe calcified aortic valve disease is generally detected.


BACKGROUND
Aortic stenosis with discordant markers of severity, AVA in severe range but low MG, is a conundrum, unresolved by outcome studies.


METHODS
Patients (n = 646) with normal left ventricular ejection fraction AS underwent Doppler echocardiography and AVC measurement by MDCT. On the basis of AVA-indexed-to-body surface area (AVAi) and MG, patients were categorized as concordant severity grading (CG) with moderate AS (AVAi >0.6 cm²/m², MG <40 mm Hg), severe AS (AVAi ≤0.6 cm²/m², MG ≥ 40 mm Hg), discordant-severity-grading (DG) with low-MG (AVAi ≤0.6 cm(2)/m(2), MG <40 mm Hg), or high-MG (AVAi >0.6 cm(2)/m(2), MG ≥40 mm Hg).


RESULTS
The MG (discordant in 29%) was strongly determined by AVA and flow but also independently and strongly influenced by AVC-load (p < 0.0001) and systemic arterial compliance (p < 0.0001). The AVC-load (median [interquartile range]) was similar within patients with DG (low-MG: 1,619 [965 to 2,528] arbitrary units [AU]; high-MG: 1,736 [1,209 to 2,894] AU; p = 0.49), higher than CG-moderate-AS (861 [427 to 1,519] AU; p < 0.0001) but lower than CG-severe-AS (2,931 [1,924 to 4,292] AU; p < 0.0001). The AVC-load thresholds separating severe/moderate AS were defined in CG-AS with normal flow (stroke-volume-index >35 ml/m(2)). The AVC-load, absolute or indexed, identified severe AS accurately (area under the curve ≥0.89, sensitivity ≥86%, specificity ≥79%) in men and women. Upon application of these criteria to DG-low MG, at least one-half of the patients were identified as severe calcified aortic valve disease, irrespective of flow.


CONCLUSIONS
Among patients with AS, MG is often discordant from AVA and is determined by multiple factors, valvular (AVC) and non-valvular (arterial compliance) independently of flow. The AVC-load by MDCT, strongly associated with AS severity, allows diagnosis of severe calcified aortic valve disease. At least one-half of the patients with discordant low gradient present with heavy AVC-load reflective of severe calcified aortic valve disease, emphasizing the clinical yield of AVC quantification by MDCT to diagnose and manage these complex patients.
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Marie-Annick
MA
Clavel
Cardiology Department, AP-HP, Bichat Hospital, Paris, France; INSERM U698 and University Paris 7-Diderot, Paris, France.
David
D
Messika-Zeitoun
Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Québec, Canada.
Philippe
P
Pibarot
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Shivani R
SR
Aggarwal
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Joseph
J
Malouf
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Phillip A
PA
Araoz
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Hector I
HI
Michelena
Cardiology Department, AP-HP, Bichat Hospital, Paris, France.
Caroline
C
Cueff
Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Québec, Canada.
Eric
E
Larose
Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Québec, Canada.
Romain
R
Capoulade
Cardiology Department, AP-HP, Bichat Hospital, Paris, France; INSERM U698 and University Paris 7-Diderot, Paris, France.
Alec
A
Vahanian
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota. Electronic address: sarano.maurice@mayo.edu.
Maurice
M
Enriquez-Sarano
D000368:Aged; D000704:Analysis of Variance; D001021:Aortic Valve / Q000473:pathology*; D001024:Aortic Valve Stenosis / Q000473:pathology*; D001783:Blood Flow Velocity; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D061330:Multidetector Computed Tomography; D015999:Multivariate Analysis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D061205:Vascular Calcification / Q000473:pathology*
AU; AVAi; AVC; AVCd; AVCi; CG; DG; Doppler echocardiography; LV; LVEF; LVOT; MDCT; MG; ROC; SV; SVi; Vmax; aortic valve area indexed to body surface area; aortic valve calcification; aortic valve calcification indexed to body surface area; aortic valve calcification indexed to the cross-sectional area of the aortic annulus; aortic valve stenosis; arbitrary units; concordant grading; discordant grading; left ventricular; left ventricular ejection fraction; left ventricular outflow tract; mean gradient; multidetector computed tomography; peak aortic jet velocity; receiver-operating characteristic; stroke volume; stroke volume indexed to body surface area