1. BACKGROUND
• Patients with paradoxical, low-flow, low-gradient, severe
aortic stenosis and normal ejection fraction (PLFLGSAS) are
common, and have an adverse prognosis.
• Aortic valve replacement, either with surgery or transcatheter
therapy, has been associated with improved survival in
PLFLGSAS patients.
• Stroke volume index (SVI) is powerful predictor of prognosis.
• Presently, there is a paucity of data on patterns and
predictors of improvement in SVI following transcatheter
aortic valve replacement (TAVR).
METHODS
Patient Population
• Evaluated and treated at the Minneapolis Heart Institute at
Abbott Northwestern Hospital between October, 2011 and
February, 2015.
• Severe aortic stenosis, defined as aortic valve area <1.0 cm2.
• Normal left ventricular ejection fraction (≥50%).
• Transcatheter aortic valve replacement with either self-
expanding (Medtronic CoreValve) or balloon-expandable
prostheses (Edwards Sapien XT or S3).
• Consent for research participation and review of the medical
record, per Minnesota state law.
Definitions and Calculations
• Stroke volume index (SVI), calculated from
echocardiography:
LVOT TVI (cm) x LVOT diameter2 (cm2)
LVOT = left ventricular outflow tract; BSA = body surface area
• Doppler echocardiography for mean aortic valve gradient
(mmHg), peak aortic velocity (m/s), aortic valve area (cm2).
• Blood pressure (mmHg) measured by arm-cuff
sphygmomanometer at time of echocardiography.
• Valvuloarterial impedance (Zva)
Mean aortic gradient + systolic BP
• Calculations performed within 30 days prior to TAVR, and
repeated within 30 days following TAVR.
Data analysis
• Regression analyses performed for relation of change in SVI
following TAVR and clinical, echocardiographic, and
procedural variables.
• Statistical significance set a priori at p<0.05.
TABLES
Demographics and Clinical Data of Patients in
Baseline Characteristics
FIGURES
CONCLUSIONS
• Changes in SVI in patients with PLFLGSAS who
undergo TAVR are related to baseline hemodynamics
and their changes following the procedure, but not
age, body habitus, or morbidity.
• The strongest predictors of improvement in SVI after
TAVR in patients with PLFLGSAS are the SVI at
baseline, and the post-procedural values for cardiac
output, aortic valve area, and ZVa.
• These findings may have implications on selection of
prosthesis for effective orifice area, as well as
management of causes of high impedance (e.g.,
hypertension).
DISCLOSURES
• The authors have no disclosures to report
ABSTRACT
BACKGOUND: Stroke volume index
(SVI) is powerful predictor of prognosis in
patients with severe aortic stenosis and
normal ejection fraction. However, there
is a paucity of data on patterns and
predictors of improvement in SVI
following transcatheter aortic valve
replacement (TAVR).
METHODS: We examined 114 patients
with severe aortic atenosis who had
TAVR at our institution (83±8 yrs, 51%
women). Using Doppler
echocardiographic data, hemodynamic
indices of valvuloarterial impedance
(Zva), SVI, and cardiac output (CO) were
derived. Regression analyses were
performed to determine clinical variables
predictive of changes in SVI after TAVR.
RESULTS: Improvement in SVI after
TAVR was significantly related to pre-
procedural Zva (R±SE, 0.37±0.74;
p=0.0001) and SVI (-0.43±0.11;
p<0.0001), but not left ventricular ejection
fraction (p=0.52), aortic valve gradient
(p=0.46), nor peak aortic velocity (p=0.33)
[Figure]. Moreover, TAVR led to
improvement in SVI (+5.1 l/min/m2;
p=0.004), Zva (-1.32 mmHg/ml/m2);
p=0.002), and CO (+1.06 l/min; p<0.0001)
in patients with SVI<35 ml/min/m2, but
not in those with SVI>35 ml/min/m2 (all
p>0.10). Post-implant aortic valve area
also was a significant predictor of
improvement in SVI in all patients (R±SE,
0.54±1.5;p<0.0001).
CONCLUSIONS: TAVR leds to
improvement in SVI in patients with
clinical findings of low-flow and high
valvulo-arterial impedance, and in those
in whom a larger AVA is achieved. The
routine assessment of these
hemodynamic parameters should be
performed in evaluation of these patients.
CORRESPONDENCE
Paul Sorajja, MD
Director, Center for Valve and
Structural Heart Disease
Minneapolis Heart Institute
Email: paul.sorajja@allina.com
Phone: (612) 863-8751
Patterns and Predictors of Stroke Volume Change with Transcatheter Aortic Valve Replacement for Low-gradient Aortic
Stenosis and Normal Ejection Fraction
Aisha Ahmed, Richard Bae, John Lesser, Wesley A. Pedersen, Lisa Tindell, Kevin Harris, R. Saied Farivar, and Paul Sorajja
Center for Valve and Structural Heart Disease, Minneapolis Heart Institute, and the Valve Science Center, Minneapolis Heart Institute Foundation
Abbott Northwestern Hospital, Minneapolis, MN
RESULTS
Hemodynamics
BSA (m2)
All patients
N=114
Age (yr) 84 ±8
Men – no. (%) 56 (49.1)
Hypertension – no. (%) 104 (91.2)
Diabetes – no. (%) 39 (34.2)
Atrial fibrillation – no. (%) 59 (51.8)
COPD – no. (%) 33 (28.9)
O2-dependent 19 (8.8)
CAD – no. (%) 80 (70.2)
Prior PCI – no. (%) 39 (34.2)
Prior CABG – no. (%) 34 (29.8)
>1 prior sternotomy 12 (10.5)
ICD or PPM – no. (%) 28 (24.6)
Creatinine (g/dl) 1.4 ±0.9
Creatinine ≥2 g/dl 10 (8.8)
Dialysis – no. (%) 5 (4.4)
STS-PROM (%) 7.7 ±3.8
SVI
R p
Age 0.05 0.58
Height 0.13 0.19
Weight 0.04 0.62
BSA 0.02 0.84
STS-PROM 0.05 0.65
Baseline hemodynamics
LV ejection fraction (%) 0.06 0.52
Systolic blood pressure 0.14 0.16
Aortic valve gradient 0.07 0.46
Peak aortic velocity 0.09 0.33
Cardiac output 0.31 0.001
Stroke volume index 0.43 <0.0001
Aortic valve area 0.29 0.002
ZVa 0.37 0.0001
Post-TAVR hemodynamics
LV ejection fraction (%) 0.07 0.44
Systolic blood pressure 0.01 0.94
Aortic valve gradient 0.18 0.06
Peak aortic velocity 0.11 0.25
Cardiac output 0.53 <0.0001
Aortic valve area 0.55 <0.0001
ZVa 0.54 <0.0001
Variables and SVI Change
No differences in SVI change were observed in unpaired
comparisons for gender, hypertension, atrial fibrillation, diabetes,
coronary artery disease, and TAVR prosthesis type.
Baseline Post-TAVR p
Mean aortic gradient (mmHg) 33.0 ±5.8 9.2 ±4.1 <0.0001
Peak aortic velocity (m/s) 3.9 ±0.5 2.1 ±0.5 <0.0001
Systolic blood pressure (mmHg) 130 ±20 129 ±20 0.65
Cardiac output (l/min) 4.5 ±1.2 5.1 ±1.7 0.0001
Stroke volume index (ml/m2) 35.1 ±10.3 35.4 ±12.8 0.92
Aortic valve area (cm2) 0.74 ±0.16 1.76 ±0.72 <0.0001
Ejection fraction (%) 61.8 ±5.9 61.3 ± 10 0.52
Valvulo-arterial impedance
(mmHg/ml/m2)
5.1 ±1.7 4.6 ±2.0 0.009
-30
-20
-10
0
10
20
30
40
50
SVIChange(mL/kg/m2)
10 20 30 40 50 60 70
Baseline SVI (mL/kg/m2)
R2 = .182
SVIChange(mL/kg/m2)
-30
-20
-10
0
10
20
30
40
50
R2 = .301
.5 1 1.5 2 2.5 3
Post AVA (cm2)
-30
-20
-10
0
10
20
30
40
50
SVIChange(mL/kg/m2)
0 2 4 6 8 10 12
Post Zva (mmHg/mL/m2)
R2 = .291
ACKNOWLEDGEMENTS
• The investigators would like to acknowledge the
support of the Minneapolis Heart Institute
Foundation, which facilitated the initiation and
completion of this study.
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