Adjusting parameters of aortic valve stenosis severity by body size.
BACKGROUND
Adjustment of cardiac dimensions by measures of body size appears intuitively convincing and in patients with aortic stenosis, aortic valve area (AVA) is commonly adjusted by body surface area (BSA). However, there is little evidence to support such an approach.


OBJECTIVE
To identify the adequate measure of body size for the adjustment of aortic stenosis severity.


METHODS
Parameters of aortic stenosis severity (jet velocity, mean pressure gradient (MPG) and AVA) and measures of body size (height, weight, BSA and body mass index (BMI)) were analysed in 2843 consecutive patients with aortic stenosis (jet velocity ≥2.5 m/s) and related to outcomes in a second cohort of 1525 patients from the Simvastatin/Ezetimibe in Aortic Stenosis (SEAS) study.


RESULTS
Whereas jet velocity and MPG were independent of body size, AVA was significantly correlated with height, weight, BSA and BMI (Pearson correlation coefficient (r) 0.319, 0.281, 0.317 and 0.126, respectively, all p<0.001) to the effect that larger patients presented with larger AVA (less severe stenosis). Of the anthropometric measures used for linear adjustment, BSA was most effective in eliminating the correlation between AVA and body size (r=0.007), rivalled only by allometric (non-linear) models, findings that are confirmed in 1525 prospectively followed patients from the SEAS study. Predictive accuracy for aortic valve events and cardiovascular death during 46 months of follow-up was unchanged by adjusting AVA, regardless of measure of body size (area under the receiver operating curve for AVA 0.72 (CI 0.58 to 0.87) versus, for example, AVA/BSA 0.75 (CI 0.61 to 0.88), p=0.22).


CONCLUSIONS
In the assessment of aortic stenosis, linear adjustment of AVA by BSA improves comparability between patients with diverging body size without, however, increasing the predictive accuracy for clinical events in a population with mild to moderate stenosis.
University Heart Center Freiburg/Bad Krozingen, Bad Krozingen, Germany.
Jan
J
Minners
University Heart Center Freiburg/Bad Krozingen, Bad Krozingen, Germany.
Christa
C
Gohlke-Baerwolf
Department of Cardiology, University Hospital Basel, Switzerland.
Beat A
BA
Kaufmann
Department of Cardiology, Asklepios Clinic St. Georg, Hamburg, Germany.
Edda
E
Bahlmann
Institute of Medicine, University of Bergen, Haukeland University Hospital, Bergen, Norway.
Eva
E
Gerdts
Department of Medicine, Skellefteå, Sweden/Institution of Public Health and Clinical Medicine, Umeå University, Sweden.
Kurt
K
Boman
Cardiothoracic Centre, Guys and St Thomas' Hospital Trust, London, UK.
John B
JB
Chambers
Heart Center Rostock, University of Rostock, Germany.
Christoph A
CA
Nienaber
Heart Health Group and Lund University, Malmö, Sweden.
Ronnie
R
Willenheimer
Department of Cardiology, Glostrup, Copenhagen, Denmark.
Kristian
K
Wachtell
University of Oslo and Oslo University Hospital, Ullevål, Centre of Preventive Medicine, Oslo, Norway.
Ingar
I
Holme
University of Oslo and Oslo University Hospital, Ullevål, Centre of Preventive Medicine, Oslo, Norway.
Terje R
TR
Pedersen
University Heart Center Freiburg/Bad Krozingen, Bad Krozingen, Germany.
Franz-Josef
FJ
Neumann
University Heart Center Freiburg/Bad Krozingen, Bad Krozingen, Germany.
Nikolaus
N
Jander
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D001827:Body Height; D015992:Body Mass Index; D049628:Body Size; D001830:Body Surface Area; D001835:Body Weight; D015150:Echocardiography, Doppler; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult