Inconsistency in hemodynamic characterization of severe aortic stenosis Richard Nies a , Roman Pfister a , Kathrin Kuhr b , Guido Michels a, ⁎ a Department III of Internal Medicine, Heart Centre of the University of Cologne, Cologne, Germany b Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Cologne, Germany article info Article history: Received 7 June 2015 Accepted 25 June 2015 Available online 30 June 2015 Keywords: Severe aortic stenosis Low-flow low-gradient aortic stenosis Echocardiography Cardiac catheterization According to ACC/AHA [1] and ESC guidelines [2] the diagnosis of se- vere aortic valve stenosis (AVS) is made when the aortic valve area (AVA) is b 1.0 cm 2 or the mean pressure gradient (Δp mean ) is N 40 mmHg, provided the cardiac output is normal. However, many patients do not consistently fulfill these criteria to diagnose severe AVS [3]. Hachicha et al. [4] found consistent parameters in AVA and mean pressure gradient in only 38% of 512 patients with AVS examined by echocardiography. A significant number of patients have an AVA b 1.0 cm 2 but a Δp mean b 40 mmHg [3–7]. This can partially be explained by a low flow situation with for example a reduced ejection fraction (EF) or a low stroke volume (SV). Accordingly, “classical” [8] and “paradoxical” [4,5] low-flow low-gradient AVS entities have been established. Inconsistent grading may also occur in patients with a nor- mal stroke volume [4,5]. According to the Gorlin equation, which ex- presses the relation between Δ p mean and anatomic AVA, Δp mean is only 26 mmHg if AVA is 1.0 cm 2 [7]. Thus the diagnostic criteria might not be consistent in a substantial part of patients. The correct classifica- tion of AVS is important for the decision concerning its further operative or conservative management, particularly if symptoms of patients are ambiguous. Albeit echocardiography is currently the standard for estimating se- verity of AVS it is susceptible to inaccurate AVA results, since the calcu- International Journal of Cardiology 197 (2015) 309–311 ⁎ Corresponding author at: Department III of Internal Medicine, Heart Centre of the University of Cologne, Kerpenerstraße 62, D-50937 Cologne, Germany. E-mail addresses: richynies@googlemail.com (R. Nies), roman.pfister@uk-koeln.de (R. Pfister), kathrin.kuhr@uk-koeln.de (K. Kuhr), guido.michels@uk-koeln.de (G. Michels). lation is strongly determined by the diameter of the left ventricular outflow tract (LVOT) which is difficult to measure due to LVOT configu- ration [6,9]. Hence, estimating AVA and severity of AVS by invasive he- modynamics assessed during cardiac catheterization is still regarded the gold standard although not necessary in clinical routine in many cases. The objectives of this study were to investigate the rate of inconsis- tent grading of severity of AVS based on AVA and mean pressure gradi- ent assessed by cardiac catheterization and whether measures of low flow such as EF and SV affect the rate of consistency. In a retrospective observational study data of 171 consecutive pa- tients with severe AVS admitted between January 2010 and December 2012 to the Department of Cardiology, University Hospital Cologne, were analyzed. Patients older than 18 years, who had an AVA less than 1 cm 2 estimated from cardiac catheterization, and who also had mean transvalvular pressure gradients assessed by cardiac catheteriza- tion were included. Exclusion criteria were previous aortic valve re- placement. In cardiac catheterization AVA was calculated using the Gorlin formula. Cardiac output (CO) was estimated based on the Fick equation. All reported p values are 2-sided; p-values b 0.05 were consid- ered to be statistically significant. Statistical analysis was performed using IBM SPSS Statistics for Macintosh, Version 21.0. Baseline characteristics are summarized in Table 1. The patient pop- ulation was divided into an inconsistent and a consistent group of AVS based on mean pressure gradient of ≤ and N 40 mmHg in patients with an AVA b 1 cm 2 . Inconsistent AVS classification was found in 49%. AVA was significantly larger in patients with inconsistent AVS as compared to patients with consistent AVS. EF was significantly higher in patients with consistent AVS compared to inconsistent AVS. Table 2 shows the impact of low flow conditions in terms of reduced EF (≤ 50%) or a low SVI (≤ 35 ml/m 2 ) on the proportion of patients with inconsistent AVS classification. The proportion of inconsistent classification was not sig- nificantly different in patient strata of SVI, but was significantly different in strata of EF. Our analysis indicates that inconsistent grading of severe AVS is fre- quent. We found a higher incidence of inconsistent AVS than reported by Minners et al. [6]. However, the patient populations were not quite comparable. The major difference was that Minners et al. excluded pa- tients with systolic dysfunction, regional wall motion abnormalities and valve regurgitation more than grade 1, resulting in the exclusion of about 50% of examinations. In contrast, our study reflects an all- comer population without relevant exclusions since invasive evaluation of AVA was standard procedure at our institution during the time of the http://dx.doi.org/10.1016/j.ijcard.2015.06.102 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved. Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard