scholarly journals Inconsistency in aortic stenosis severity between CT and echocardiography: prevalence and insights into mechanistic differences using computational fluid dynamics

Open Heart ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. e001044 ◽  
Author(s):  
Tarun Kumar Mittal ◽  
Luise Reichmuth ◽  
Sanjeev Bhattacharyya ◽  
Manish Jain ◽  
Aigul Baltabaeva ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aortic Stenosis ◽  
Cfd Simulation ◽  
Stroke Volume Index ◽  
Ventricular Outflow Tract ◽  
Velocity Profiles ◽  
Left Ventricular ◽  
Volume Index ◽  
Aortic Valve Area

ObjectivesThe aims of this study were to evaluate the inconsistency of aortic stenosis (AS) severity between CT aortic valve area (CT-AVA) and echocardiographic Doppler parameters, and to investigate potential underlying mechanisms using computational fluid dynamics (CFD).MethodsA total of 450 consecutive eligible patients undergoing transcatheter AV implantation assessment underwent CT cardiac angiography (CTCA) following echocardiography. CT-AVA derived by direct planimetry and echocardiographic parameters were used to assess severity. CFD simulation was performed in 46 CTCA cases to evaluate velocity profiles.ResultsA CT-AVA>1 cm2 was present in 23% of patients with echocardiographic peak velocity≥4 m/s (r=−0.33) and in 15% patients with mean Doppler gradient≥40 mm Hg (r=−0.39). Patients with inconsistent severity grading between CT and echocardiography had higher stroke volume index (43 vs 38 mL/m2, p<0.003) and left ventricular outflow tract (LVOT) flow rate (235 vs 192 cm3/s, p<0.001). CFD simulation revealed high flow, either in isolation (p=0.01), or when associated with a skewed velocity profile (p=0.007), as the main cause for inconsistency between CT and echocardiography.ConclusionSevere AS by Doppler criteria may be associated with a CT-AVA>1 cm2 in up to a quarter of patients. CFD demonstrates that haemodynamic severity may be exaggerated on Doppler analysis due to high LVOT flow rates, with or without skewed velocity profiles, across the valve orifice. These factors should be considered before making a firm diagnosis of severe AS and evaluation with CT can be helpful.

scholarly journals Repeated echocardiographic imaging of aortic stenosis: Real-life lessons

2021 ◽  
Author(s):  
Jonathan Bray ◽  
Adrian Ionescu
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Intraclass Correlation ◽  
Real Life ◽  
Stroke Volume Index ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Volume Index ◽  
Aortic Valve Area ◽  
Valve Area

Background Timing of aortic valve intervention is dependent on the accuracy and reproducibility of echocardiographic (ECHO) parameters. We aimed to assess haemodynamic subsets of aortic stenosis (AS), their change over time, and variability of ECHO parameters. Method This retrospective, longitudinal study compared sequential ECHO over 15 months to identify concordant or discordant aortic valve area (AVA) and mean pressure gradient (MPG). Results We included 143 patients with a mean age of 76.0 years. The median length of time between studies was 112 days (IQR 38-208). Initially participants were classified as 10 (7.0%) mild, 49 (34.3%) moderate and 84 (58.7%) severe AS. In 80 (55.9%) AVA and MPG were concordant; stroke volume index (SVi) was <35ml/m2 in 53 (74.6%). AS severity was downgraded in 33 (23.1%) patients. MPG was most consistent and AVA was the least consistent between successive investigations (intraclass correlation coefficients R=0.86 and R=0.76, respectively). Even small variations in left ventricular outflow tract (LVOT) measurement of 1 standard deviation reclassified up to 67% of participants from severe to non-severe. Conclusion Almost half of patients with AS have valve area/gradient discordance. Variations in LVOT diameter measurement commensurate with clinical practice reclassified AS severity in up to 2/3 of cases. Change in AS severity should only be accepted following careful scrutiny of all available ECHO data.

scholarly journals P1370 Correlation of aortic stenosis by integrated transthoracic and transesophageal echocardiography with calcium score

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
S Schwartzenberg ◽  
Y Shapira ◽  
M Vaturi ◽  
M Nassar ◽  
A Hamdan ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Low Flow ◽  
Volume Index ◽  
Left Ventricular Ejection ◽  
Aortic Valve Area ◽  
Ventricular Ejection Fraction ◽  
Coronary Ct

Abstract Funding Acknowledgements None BACKGROUND Aortic stenosis (AS) classification depends on left-ventricular ejection-fraction (LVEF &lt;≥50%), aortic valve area (AVA&lt;≥1cm2), mean pressure gradient (MG&lt;≥40mmHg), peak velocity&lt;≥400 cm/sec, and stroke-volume index (SVI&lt;≥35ml/m2). Aortic Valve Agatston CT score (AVC) correlates with AS severity by trans-thoracic echo (TTE), but its association with AS severity determined by integrated TTE and TEE is unknown. PURPOSE We investigated correlation of AVC with dichotomous AS grouping by Integrated TTE + TEE vs TTE only. METHODS 64 TAVI candidates underwent sequential TTE and TEE, of which 24 underwent coronary CT within 4 months. Based on recommended conservative vs invasive treatment implication (A/B respectively), AS types were aggregated separately by TTE or Integrated TTE-TEE into two groups: Group-A (Moderate AS and Normal-Flow Low-Gradient), and Group-B (High-Gradient, Low-EF Low-Flow Low-Gradient, and Paradoxical Low-Flow Low-Gradient). Continuous and dichotomous AVC correlation (cutoffs based on guidelines) with echo binary classification was then determined. RESULTS Patients were 81.1(77.3-84.6) years old, 18(48.6%) were women, and had LVEF of 60% (49-65). AVC-score distribution in the two AS A/B Groups by two echo modalities is presented in the boxplot Figure. Only classification by TTE held discriminative accuracy in A/B grouping, with Area-Under-Curve of 0.736 (CI 0.57-0.9), and optimal threshold value of 1946 AU having 77% sensitivity and 74% specificity. Compared with AVC dichotomous classification, integrated TTE + TEE upgraded AS class (from A to B) in 5/6 (83.3%) patients vs 12/18 (66.7%) in which it downgraded AS class from B to A. CONCLUSIONS Aortic valve calcification correlates well with AS class dichotomized by operative implication through conventional TTE but not through integrated TTE + TEE. Our preliminary results appear to be caused by initial selection bias of patients in whom coronary CT performance was deemed to be justified by the treating physician rather than reflect a true better correlation between CT score and AS assessment by TTE vs by integrated TTE + TEE. Abstract P1370 Figure.

scholarly journals Use of passive leg rise as an add-on to dobutamine in patients with paradoxical low-flow, low-gradient aortic stenosis

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
E Buffle ◽  
A Papadis ◽  
C Seiler ◽  
S F De Marchi
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Ejection Fraction ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Low Flow ◽  
Volume Index ◽  
Aortic Valve Area ◽  
Low Ejection Fraction ◽  
Valve Area

Abstract Background Dobutamine has been proposed for the assessment of low-flow, low-gradient aortic stenosis (LFLGAS). However, in 1/3 of patients, no increase in stroke volume index can be achieved by Dobutamine, thus hampering its diagnostic value. This study evaluated the manoeuvre of cardiac preload augmentation by passive leg rise (PLR) alone or on top of Dobutamine to increase stroke volume index (SVI) in patients with LFLGAS, particularly in paradoxical LFLGAS. Methods We examined 50 patients with LFLGAS. Patients were assigned to the paradoxical LFLGAS (Paradox) group if left ventricular ejection fraction (LVEF) was ≥50% (n=29) and to the LFLGAS with low ejection fraction (LEF) group if LVEF was &lt;50% (n=21). A modified Dobutamine stress echocardiography was performed in all patients with the following 4 steps: Rest, PLR alone, maximal Dobutamine infusion rate alone (Dmax) and Dobutamine plus PLR (Dmax + PLR). Three SVI measurement methods were used: first the left ventricular outflow tract velocity time integral (LVOT VTI) method, second the 2D Simpson's method, and third the 3D method. The corresponding aortic valve area (AVA) was obtained by the continuity equation. The increase of those values compared to measurements at rest was calculated and compared between the 3 stress steps. Results In the paradoxical LFLGAS group, delta SVI with Dmax assessed by both Simpson's (depicted in the figures) and 3D method was lowest compared to PLR and Dmax + PLR. PLR alone yielded an equally high delta SVI as Dmax + PLR in Simpson's and 3D, and was at least as high as Dmax across all methods. Dobutamine alone yielded the lowest delta transaortic aortic valve VTI. The highest delta aortic valve area resulted for Dmax + PLR. In the LEF group, the three stress steps yielded an equally high delta SVI with Simpson's method. Dmax never yielded a higher delta SVI than PLR alone. The yielded delta SVI was the highest for Dmax + PLR for both LVOT VTI and 3d method, although the difference was overall not as strong as in the Paradox group. Conclusions In patients with paradoxical LFLGAS, Dobutamine alone is inadequate for testing the potential of aortic valve opening augmentation. Instead, PLR alone or the addition of PLR plus Dobutamine should be used for that purpose. In low LVEF, adding PLR to Dobutamine also seems useful although its diagnostic added value is less evident than in the Paradox group. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Gottfried und Julia Bangerter-Rhyner-Foundation Paradox group Low ejection fraction group

Left atrial dynamics in the hemodynamic response during exercise in patients with asymptomatic severe aortic stenosis: a cardiopulmonary imaging study

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T Sugimoto ◽  
F Bandera ◽  
M Barletta ◽  
E Alfonzetti ◽  
M Guazzi
Keyword(s):  
Aortic Stenosis ◽  
Left Atrial ◽  
Cardiopulmonary Exercise Testing ◽  
Systolic Pressure ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Low Flow ◽  
Volume Index ◽  
Aortic Valve Area ◽  
Significant Difference

Abstract Background The hemodynamic impact of left atrial (LA) dynamics in aortic stenosis (AS) in relation to cardiopulmonary response to exercise has never been studied. We aimed at investigating the link between LA function vs valvulo-arterial impedance (Zva) and right ventricular (RV)-to-pulmonary circulation (PC) coupling in asymptomatic severe AS patients. Methods A total of 94 patients: 64 asymptomatic severe AS patients (aortic valve area (AVA) &lt;1.0 cm2 or AVA index &lt;0.6 cm2/m2) with ejection fraction &gt;50% and 30 gender-matched control subjects underwent cardiopulmonary exercise testing combined with Echo-Doppler with assessment of LA strain and RV-to-PC coupling (tricuspid annular peak systolic excursion (TAPSE)/ pulmonary arterial systolic pressure (PASP) ratio). AS patients were divided into 3 groups according to peak aortic jet velocity (PV), mean pressure gradient (MPG) and stroke volume index (SVI). Zva was assessed using (MPG + systolic blood pressure)/ SVI ratio. Results Paradoxical low-flow low-gradient AS (PLFLG: PV &lt;4 m/s and MPG &lt;40 mmHg, SVI ≤35ml/m2, N=18, AVA 0.77±0.16 cm2), Normal-flow low-gradient AS (NFLG: PV &lt;4 m/s and MPG &lt;40 mmHg, SVI &gt;35ml/m2, N=23, AVA 0.85±0.16 cm2) and High-gradient AS (HG: PV ≥4 m/s or MPG ≥40 mmHg, N=20, AVA 0.62±0.17 cm2) had a higher LA volume index than Control (Control 22±6, PLFLG 33±11*, NFLG 38±12* and HG 33±9* ml/m2, *P&lt;0.05 vs Control). There was no significant difference in peak VO2 (17±5 ml/min/kg) and VE/VCO2 slope (28±3) among 3 AS groups although PLFLG had lower peak cardiac output (7.0±2.4 L/min) compared to NFLG (9.0±2.3 L/min) and HG (9.2±3.3 L/min). In PLFLG and NFLG AS, LA strain at rest (21±9 and 26±13%) and during exercise (26±12 and 31±14%) were decreased compared to Control (37±8% at rest, 43±11% during exercise) but maintained some reserve during exercise (P&lt;0.001). HG AS had no increase in LA strain (31±15% at rest, 28±15% during exercise) (Figure A). In AS groups, no significant correlation at rest was observed between LA strain and Zva, whereas a negative correlation was observed during exercise (R=−0.4, P=0.003, Figure B). LA strain was also correlated with TAPSE/PASP at rest and exercise (R=0.44 and 0.47, P&lt;0.01, respectively, Figure C). Conclusions In asymptomatic severe AS, the study of LA functional adaptation to exercise plays a key role in the hemodynamic unfavorable cascade from AS-related left ventricular afterload to RV-to-PC uncoupling. Funding Acknowledgement Type of funding source: None

P6470Ventriculo-arterial coupling in severe aortic stenosis: does the flow-gradient pattern play a role?

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A E Vijiiac ◽  
C Neagu ◽  
A Cherry ◽  
S Onciul ◽  
D Zamfir ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Severe Aortic Stenosis ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Low Flow ◽  
Volume Index ◽  
Aortic Valve Area ◽  
Arterial Elastance ◽  
Ventricular Elastance ◽  
Flow Gradient

Abstract Background Ventriculo-arterial coupling (VAC) assesses the interplay between ventricular contractility and afterload and it is calculated as the ratio between arterial elastance (Ea) and end-systolic left ventricular elastance (EES). Severe aortic stenosis (AS) carries different configurations according to transvalvular flow rates and pressure gradients and each of these entities has its particularities in terms of physiology and clinical outcome. Little has been studied so far regarding the changes of VAC in severe AS. Purpose We sought to assess the VAC non-invasively in patients (pts) with severe AS and to characterize it according to the flow-gradient pattern. Methods We included 61 consecutive pts with severe AS (78±13 years, 30 men, indexed aortic valve area <0.6 cm2/m2), for whom we performed a comprehensive echocardiography. VAC was determined as the ratio between Ea and EES. Patients were divided in 4 groups, depending on stroke volume index (low-flow [LF] vs. normal-flow [NF]: 35 ml/m2) and mean transaortic pressure gradient (low-gradient [LG] vs. normal gradient [NG]: 40 mm Hg). This resulted in the following flow-gradient patterns: LFLG, LFNG, NFLG, NFNG. Data were compared between groups with one-way analysis of variance and then with a Tukey test. Results There were 11 pts (18%) in the LFLG group, 20 pts (32.8%) in the LFNG group, 8 pts (13.2%) in the NFLG group and 22 pts (36%) in the NGNG group. The arterial elastance was highest in the LFLG group: 3.37±1.49 vs. 2.79±0.92 in the LFNG, 2.05±0.57 in the NFLG and 1.54±0.49 in the NFNG group (p<0.001). The ventricular elastance was also highest in the LFLG group (4.03±2.46) vs. 3.16±1.33 in the LFNG, 2.21±1.22 in the NFLG and 2.29±0.78 in the NFNG group (p=0.007). VAC was most impaired in the NFLG group (1.35±1.08), followed by LFNG group (1.00±0.47), LFLG group (0.93±0.27) and NFNG group (0.70±0.14) (p=0.01). Valvulo-arterial impedance (ZVA) was highest in the LFNG group: 7.78±2.15, followed by 7.38±2.17 in the LFLG group, 4.93±1.17 in the NFLG group and 4.33±1.23 in the NFNG group (p<0.001). VAC and ZVA showed no significant correlation (p=0.27), with VAC being significantly more impaired in patients with abnormal ZVA (>4.5 mm Hg/ml/m2): 0.99±0.60 vs. 0.73±0.20 (p=0.02). Conclusion The ventriculo-vascular interaction in severe AS varies noticeably according to the flow-gradient pattern. Low-gradient states, particularly NFLG, have the most impaired VAC. This study supports the idea that these 4 configurations are different clinical entities and it highlights the importance of integrating the flow-gradient pattern for a comprehensive evaluation of AS severity. Acknowledgement/Funding This work was supported by CREDO Project - ID: 49182, financed through the SOP IEC -A2-0.2.2.1-2013-1 cofinanced by the ERDF

scholarly journals Discordant severity criteria in patients with moderate aortic stenosis: prognostic implications

Open Heart ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. e001639
Author(s):  
Stephan M Pio ◽  
Mohammed R Amanullah ◽  
Steele C Butcher ◽  
Kenny Y Sin ◽  
Nina Ajmone Marsan ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Ejection Fraction ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Volume Index ◽  
Aortic Valve Area ◽  
Risk Of Mortality ◽  
Lv Ejection Fraction ◽  
Prognostic Implications

BackgroundThe criteria to define the grade of aortic stenosis (AS)—aortic valve area (AVA) and mean gradient (MG) or peak jet velocity—do not always coincide into one grade. Although in severe AS, this discrepancy is well characterised, in moderate AS, the phenomenon of discordant grading has not been investigated and its prognostic implications are unknown.ObjectivesTo investigate the occurrence of discordant grading in patients with moderate AS (defined by an AVA between 1.0 cm² and 1.5 cm² but with an MG <20 mm Hg) and how these patients compare with those with concordant grading moderate AS (AVA between 1.0 cm² and 1.5 cm² and MG ≥20 mm Hg) in terms of clinical outcomes.MethodsFrom an ongoing registry of patients with AS, patients with moderate AS based on AVA were selected and classified into discordant or concordant grading (MG <20 mm Hg or ≥20 mm Hg, respectively). The clinical endpoint was all-cause mortality.ResultsOf 790 patients with moderate AS, 150 (19.0%) had discordant grading, moderate AS. Patients with discordant grading were older, had higher prevalence of previous myocardial infarction and left ventricular (LV) hypertrophy, larger LV end-diastolic and end-systolic volume index, higher LV filling pressure and lower LV ejection fraction and stroke volume index as compared with their counterparts. After a median follow-up of 4.9 years (IQR 3.0–8.2), patients with discordant grading had lower aortic valve replacement rates (26.7% vs 44.1%, p<0.001) and higher mortality rates (60.0% vs 43.1%, p<0.001) as compared with patients with concordant grading. Discordant grading moderate AS, combined with low LV ejection fraction, presented the higher risk of mortality (HR 2.78 (2.00–3.87), p<0.001).ConclusionDiscordant-grading moderate AS is not uncommon and, when combined with low LV ejection fraction, is associated with high risk of mortality.

scholarly journals Impact of the Trifecta bioprosthetic valve in patients with low-flow severe aortic stenosis

2021 ◽  
Author(s):  
Tohru Takaseya ◽  
Atsunobu Oryoji ◽  
Kazuyoshi Takagi ◽  
Tomofumi Fukuda ◽  
Koichi Arinaga ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Severe Aortic Stenosis ◽  
Stroke Volume Index ◽  
Low Flow ◽  
Volume Index ◽  
Effective Orifice Area ◽  
Aortic Valve Area ◽  
Hemodynamic Performance ◽  
Mid Term Results

AbstractAortic stenosis (AS) is the most common valve disorder in advanced age. Previous reports have shown that low-flow status of the left ventricle is an independent predictor of cardiovascular mortality after surgery. The Trifecta bioprosthesis has recently shown favorable hemodynamic performance. This study aimed to evaluate the effect of the Trifecta bioprosthesis, which has a large effective orifice area, in patients with low-flow severe AS who have a poor prognosis. We retrospectively evaluated 94 consecutive patients with severe AS who underwent aortic valve replacement (AVR). Patients were divided into two groups according to the stroke volume index (SVI): low-flow (LF) group (SVI < 35 ml/m2, n = 22) and normal-flow (NF) group (SVI ≥ 35 ml/m2, n = 72). Patients’ characteristics and early and mid-term results were compared between the two groups. There were no differences in patients’ characteristics, except for systolic blood pressure (LF:NF = 120:138 mmHg, p < 0.01) and the rate of atrial fibrillation between the groups. A preoperative echocardiogram showed that the pressure gradient was higher in the NF group than in the LF group, but aortic valve area was similar. The Trifecta bioprosthesis size was similar in both groups. The operative outcomes were not different between the groups. Severe patient–prosthesis mismatch (PPM) (< 0.65 cm2/m2) was not observed in either of the groups. There were no significant differences in mid-term results between the two groups. The favorable hemodynamic performance of the Trifecta bioprosthesis appears to have the similar outcomes in the LF and NF groups. AVR with the Trifecta bioprosthesis should be considered for avoidance of PPM, particularly in AS patients with LV dysfunction.

scholarly journals Impact of left ventricular outflow tract flow acceleration on aortic valve area calculation in patients with aortic stenosis

2019 ◽  
Vol 6 (4) ◽  
pp. 97-103 ◽  
Author(s):  
Andaleeb A Ahmed ◽  
Robina Matyal ◽  
Feroze Mahmood ◽  
Ruby Feng ◽  
Graham B Berry ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Continuity Equation ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Area Measurement ◽  
Aortic Valve Area ◽  
Flow Acceleration ◽  
The Impact ◽  
Valve Area

Objective Due to its circular shape, the area of the proximal left ventricular tract (PLVOT) adjacent to aortic valve can be derived from a single linear diameter. This is also the location of flow acceleration (FA) during systole, and pulse wave Doppler (PWD) sample volume in the PLVOT can lead to overestimation of velocity (V1) and the aortic valve area (AVA). Therefore, it is recommended to derive V1 from a region of laminar flow in the elliptical shaped distal LVOT (away from the annulus). Besides being inconsistent with the assumptions of continuity equation (CE), spatial difference in the location of flow and area measurement can result in inaccurate AVA calculation. We evaluated the impact of FA in the PLVOT on the accuracy of AVA by continuity equation (CE) in patients with aortic stenosis (AS). Methods CE-based AVA calculations were performed in patients with AS once with PWD-derived velocity time integral (VTI) in the distal LVOT (VTILVOT) and then in the PLVOT to obtain a FA velocity profile (FA-VTILVOT) for each patient. A paired sample t-test (P < 0.05) was conducted to compare the impact of FA-VTILVOT and VTILVOT on the calculation of AVA. Result There were 46 patients in the study. There was a 30.3% increase in the peak FA-VTILVOT as compared to the peak VTILVOT and AVA obtained by FA-VTILVOT was 29.1% higher than obtained by VTILVOT. Conclusion Accuracy of AVA can be significantly impacted by FA in the PLVOT. LVOT area should be measured with 3D imaging in the distal LVOT.

scholarly journals P289 Aortic valve resistance risk-stratifies low-gradient aortic stenosis

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
J Cho ◽  
T Uejima ◽  
H Nishikawa ◽  
J Yajima ◽  
T Yamashita
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Stroke Volume ◽  
Clinical Decision Making ◽  
Stroke Volume Index ◽  
Low Flow ◽  
Volume Index ◽  
Aortic Valve Area ◽  
Event Free Survival ◽  
Free Survival

Abstract Background Grading the severity of aortic stenosis (AS) is challenging, since there is a discrepancy between aortic valve area (AVA) and mean pressure gradient (mPG). Arotic valve resistance (RES) has been proposed as a usuful descriptor of AS severity, but it is not commonly used for clinical decision-making, because its robust validation of clinical-outcome efficacy is lacking. This study aimed to investigate whether RES holds an incremental value for risk-stratifying AS. Methods This study recuited 565 AS patients (AVA &lt; 1.5cm²) referred to echocardiography for valve assessment. The patients were divided into three different groups, according to the guidelines: high-gradient AS (HG-AS, mPG≥40mmHg, n = 157), low-gradient AS (LG-AS, mPG &lt; 40mmHg + AVA ≤ 1.0cm², n = 155) and moderate AS (Mod-AS, mPG &lt; 40mmHg + AVA &gt; 1.0cm², n = 253). RES was calculated from Doppler measurement of mPG and stoke volume. The diagnositic cutoff point for RES was determined at 190 dynes × s×cm-5 by substituting AVA = 1.0cm² and mPG = 40mmHg into the definition formula of RES and Gorlin formula. The patients were followed up for 2 years. The endpoint was a composite of cardiac death, hospitalization for heart failure and aortic valve replacement necessitated by the development of AS-related symptoms. Result Kaplan-Meier analyses showed that LG-AS exhibited an intermediate outcome between HG-AS and Mod-AS (event-free survival at 2 years = 20.9% for HG-AS, 59.7% for LG-AS, 89.9% for Mod-AS, p &lt; 0.001, figure A). When LG-AS was stratified by RES, the survival curves showed a significant separation (event-free survival at 2 years = 35.3% for high RES, 70.7% for low RES, p &lt; 0.001, figure B). This trend persisted even when analysed separately for norml (stroke volume index &gt; 35ml/m²) and low (stroke volume index ≤ 35ml/m²) flow state ((normal flow) event-free survival at 2 years = 38.7% for high RES, 70.4% for low RES, p = 0.023, figure C; (low flow) event-free survival at 2 years = 26.7% for high RES, 74.6% for low RES, p &lt; 0.001, figure D). Conclusion This study confirmed the clinical efficacy of RES for risk-stratifying LG-AS patients. Abstract P289 Figure.

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