Comparison of outcome of higher versus lower transvalvular gradients in patients with severe aortic stenosis and low (<40%) left ventricular ejection fraction.
ABSTRACT Left ventricular systolic dysfunction in patients with severe aortic stenosis (AS) is associated with poor outcome. This analysis was designed primarily to describe the clinical course of a large series of consecutive patients with severe AS and low ejection fraction (EF) (<40%) who, because of high surgical risk, were referred for transcatheter aortic valve implantation consideration. A cohort of 270 patients with severe AS and low EF (<40%) who were referred to participate in a clinical trial of transcatheter aortic valve implantation was studied. Clinical, hemodynamic, and periprocedural complications and follow-up mortality data were collected and compared between patients with low mean transvalvular gradients (≤40 mm Hg, n = 170 [63%]) and high transvalvular gradients (>40 mm Hg, n = 100 [37%]). Patients with low gradients were younger (mean age 79.8 ± 9.1 vs 83.8 ± 7.7 years, p <0.001) and had higher incidences of coronary artery disease and renal failure. Mean aortic valve area was larger (0.73 ± 0.23 vs 0.53 ± 0.18 cm(2), p <0.001), while mean EF (26.4 ± 6.9% vs 30.5% ± 6.6%, p <0.001), cardiac output (3.7 ± 1.1 vs 4.1 ± 1.3 L/min, p = 0.04), and cardiac index (1.9 ± 0.5 vs 2.1 ± 0.6 L/min/m(2), p = 0.04) were lower in patients with lower gradients compared to those with higher gradients, respectively. Mortality was higher in patients with low gradients (53.8%) at a mean follow-up of 151 days compared to those with high gradients (41%) at a mean follow-up of 256 days (p = 0.01). In conclusion, patients with severe AS and low EF with low transvalvular gradients are at higher risk for worse outcomes compared to patients with high transvalvular gradients. Surgery or transcatheter aortic valve implantation treatment and high baseline transvalvular gradient are associated with EF improvement.
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ABSTRACT: Low-flow, low-gradient (LF-LG) aortic stenosis (AS) may occur with depressed or preserved left ventricular ejection fraction (LVEF), and both situations are among the most challenging encountered in patients with valvular heart disease. In both cases, the decrease in gradient relative to AS severity is due to a reduction in transvalvular flow. The main challenge in patients with depressed LVEF is to distinguish between true severe versus pseudosevere stenosis and to accurately assess the severity of myocardial impairment. Paradoxical LF-LG severe AS despite a normal LVEF is a recently described entity that is characterized by pronounced LV concentric remodeling, small LV cavity size, and a restrictive physiology leading to impaired LV filling, altered myocardial function, and worse prognosis. Until recently, this entity was often misdiagnosed, thereby causing underestimation of AS severity and inappropriate delays for surgery. Hence, the main challenge in these patients is proper diagnosis, often requiring diagnostic tests other than Doppler echocardiography. The present paper proposes to review the diagnostic and therapeutic management specificities of LF-LG AS with and without depressed LV function.Journal of the American College of Cardiology 10/2012; · 14.09 Impact Factor
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ABSTRACT: Objectives: To identify predictors of mortality, functional status and hemodynamical changes of patients undergoing TAVI for low flow/low gradient AS (LF/LG AS). Background: There is little published data regarding the outcomes of patients with LF/LG AS following transcatheter aortic valve implantation (TAVI). Methods: Sixty-eight patients with severe AS, left ventricular dysfunction (ejection fraction (EF) <35%) and low flow AS underwent TAVI. Patients were stratified according to the aortic mean pressure gradient (low gradient (LG); with Pmean ≤ 40 mmHg and high gradient (HG): Pmean >40 mmHg.) The baseline parameters and clinical outcomes were subsequently compared among the two groups. Cox proportional hazards were used to identify predictors of 6-month mortality. Results: There were 38 patients in the LG group and 30 patients in the HG group. There were no significant difference in 30-day mortality between the two groups. The 6-month and 1-year mortality, however, was 3.8-fold higher in the LG group than in the HG group (37.8 vs. 10.3%, p=0.01 and 37.8 vs 13.3%, respectively, p=0.01). Univariable predictors for 6-month mortality were: STS Score, aortic valve area and aortic mean pressure gradient. However, only STS Score (HR 1.08, 1.04-1.12, p<0.001) remained as independent predictor in the multivariable analysis. Six months after TAVI, hemodynamical (EF>50%) and clinical (NYHA class I) improvements were shown in both HG and LG groups. Conclusions: LF/LG AS does not influence procedural mortality after TAVI but exhibits a strong impact on 6-month and 1-year mortality. The survivors however, exhibit considerable hemodynamical and clinical improvements. Therefore, risk stratification and TAVI benefit should be weighted in every patient with LF/LG AS. © 2014 Wiley Periodicals, Inc.Catheterization and Cardiovascular Interventions 01/2014; · 2.51 Impact Factor
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ABSTRACT: BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an alternative treatment of severe symptomatic aortic stenosis (AS) in patients with high operative risk. In spite of favorable entire results, long-term mortality of patients is high. HYPOTHESIS: The present study aims to identify independent preprocedural risk factors to improve risk stratification in these highly selected patients. METHODS: This prospective study included 202 consecutive patients with severe symptomatic AS and high operative risk (mean logistic European System for Cardiac Operative Risk Evaluation, 22 ± 17%; mean age, 79 ± 6 years; 107 female). Preprocedural comprehensive examinations were performed (laboratory, electrocardiography, echocardiography, cardiac catheterization). All patients received transfemoral or transaxillary TAVI with a CoreValve prosthesis (Medtronic, Minneapolis, MN). RESULTS: During a follow-up of 535 ± 333 days, 56 patients (28%) reached the primary study end point (all-cause mortality). Independent predictors of long-term mortality were as follows: hemoglobin <12.5 g/dL (hazard risk [HR], 3.62; 95% confidence interval [CI], 2.025-6.468; P < 0.001), aortic mean gradient ≤41 mm Hg (HR, 2.16; 95% CI, 1.272-3.655; P = 0.004), and left atrial diameter > 42 mm (HR, 3.09; 95% CI, 1.588-6.019; P = 0.001). Our risk-stratification model based on these independent predictors separated patients into 4 groups with high (74%), intermediate (37%), low (18%), and very low (3%) all-cause mortality. CONCLUSIONS: In patients undergoing TAVI, preprocedural assessment of hemoglobin, aortic mean gradient, and left atrial diameter provides independent prognostic information and therefore contributes to improved risk stratification in TAVI.Clinical Cardiology 02/2013; · 1.83 Impact Factor
Comparison of Outcome of Higher Versus Lower Transvalvular
Gradients in Patients With Severe Aortic Stenosis and Low
( < 40%) Left Ventricular Ejection Fraction
ltsik Ben-Dor, MD, Gabriel Maluenda, MD, Getachew D. Iyasu, MD, Ana Laynez-Camicero, MD,
Camille Hauville, MD, Rebecca Torguson, MPH, Petros Okubagzi, MD, Zhenyi Xue, MS,
Steven A. Goldstein, MD, PhD, Joseph Lindsay, MD, Lowell F. Satler, MD,
Augusto D. Pichard, MD, and Ron Waksman, MD*
Left ventricular systolic dysfunction in patients with severe aortic stenosis (AS) is associ-
ated with poor outcome. This analysis was designed primarily to describe the clinical course
of a large series of consecutive patients with severe AS and low ejection fraction (EF)
( < 40%) who, because of high surgical risk, were referred for transcatheter aortic valve
implantation consideration. A cohort of 270 patients with severe AS and low EF ( <40%)
who were referred to participate in a clinical trial of transcatheter aortic valve implantation
was studied. Clinical, hemodynamic, and periprocedural complications and follow-up
mortality data were collected and compared between patients with low mean transvalvular
gradients (::540 mm Hg, n = 170 [63%]) and high transvalvular gradients (>40 mm Hg, n =
100 [37%]). Patients with low gradients were younger (mean age 79.8 ± 9.1 vs 83.8 ± 7.7
years, p <0.001) and had higher incidences of coronary artery disease and renal failure.
Mean aortic valve area was larger (0.73 ± 0.23 vs 0.53 ± 0.18 cm2, p <0.001), while mean
EF (26.4 ± 6.9% vs 30.5% ± 6.6%, p <0.001), cardiac output (3.7 ± 1.1 vs 4.1 ± 1.3 Llmin,
p = 0.04), and cardiac index (1.9 ± 0.5 vs 2.1 ± 0.6 Llmin/m2, p = 0.04) were lower in
patients with lower gradients compared to those with higher gradients, respectively.
Mortality was higher in patients with low gradients (53.8%) at a mean follow-up of 151
days compared to those with high gradients (41%) at a mean follow-up of 256 days (p =
0.01). In conclusion, patients with severe AS and low EF with low transvalvular gradients
are at higher risk for worse outcomes compared to patients with high transvalvular
gradients. Surgery or transcatheter aortic valve implantation treatment and high baseline
transvalvular gradient are associated with EF improvement. © 2012 Published by
Elsevier Inc. (Am J Cardiol 2012;109:1031-1037)
Patients with severe aortic stenosis (AS) and reduced left
ventricular ejection fraction (EF) have a poor prognosis
when treated medically. Consequently, despite relatively
high operative risk, surgical aortic valve replacement
(SAVR) is recommended for such patients.1•2 Operative risk
is particularly high in patients with low transvalvular mean
gradients.3 Transcatheter aortic valve implantation (TAVI)
has been introduced as an alternative to SA VR in high-risk
patients with severe AS. This analysis was designed primar-
ily to describe the clinical course of a large series of con-
secutive patients with severe AS and low EF ( <40%) who,
because of high surgical risk, were referred for T A VI con-
sideration. Second, we sought to compare the clinical
courses of patients with low transvalvular gradients (:S40
mm Hg) to those of patients with similarly severe AS and
higher transvalvular gradients (>40 mm Hg). Finally, in
patients with severe AS and low EF ( <40% ), we s o u ~ h t to
Division of Cardiology, Washington Hospital Center, Washington,
District of Columbia. Manuscript received October 3, 2011; revised man-
uscript received and accepted November 23, 2011.
*Corresponding author: Tel: 202-877-2812; fax: 202-877-2715.
E-mail address: email@example.com (R. Waksman).
0002-9149/12/$- see front matter© 2012 Published by Elsevier Inc.
compare the EF response to T A VI, SA VR, or balloon aortic
valvuloplasty (BA V).
From April 2007 to December 2010, 890 consecutive
patients with severe symptomatic AS, defined as aortic
valve area <1 cm2 or aortic valve index <0.5 cm2/m2, who
were referred for participation in a randomized T A VI trial
(Placement of Aortic Transcatheter Valves [PARTNER])
were prospectively entered into a dedicated database ::tnd
thus considered for this analysis. All patients were screened
and gave written consent for the study. Those with severe
AS (aortic valve area < 1 cm2 or aortic valve index <0.5
cm2/m2) and low EF (<40%) were included (n = 270).
The study population was divided into 2 groups: patients
with low mean transvalvular gradients ( :S40 mm Hg, n =
170 [63%]) and those with high trans valvular gradients
(>40 mm Hg, n = 100 [37%]). Within this cohort, 38
patients (14%) underwent TAVI; 232 were excluded from
the T A VI trial and received treatment on the basis of the
decisions made by a multidisciplinary team (interven-
tional cardiologist, cardiac surgeon, and primary cardi-
ologist). Medical treatment without other intervention
The American Journal of Cardiology (www.ajconline.org)
Baseline characteristics, clinical profile, and operative risk of patients with high versus low transvalvular gradients
Peak Transvalvular Gradient (mm Hg) p Value
(n = 170) (n = 100)
Society of Thoracic Surgeons score (%)
Logistic European System for Cardiac Operative Risk Evaluation score
Body surface area (m2)
New York Heart Association class IV
Coronary artery disease
Previous myocardial infarction
Previous coronary artery bypass grafting
Chronic obstructive pulmonary disease
Creatinine clearance <60 ml/min
Previous cerebrovascular accident/transient ischemic attack
Peripheral vascular disease
79.8 ± 9.1
14.2 ± 7.0
57.5 ± 21.9
103 (61 %)
83.8 ± 7.7
13.9 ± 7.7
54.0 ± 21.5
1.82 ± 0.25
Data are expressed as mean ± SD or as number (percentage).
* History of systemic hypertension diagnosed and/or treated with medication or currently being treated with diet and/or medication by a physician.
was given to 55 (20.3%), BAY to 144 (53.3%), and
SAVR to 33 (12.2%). All patients were followed by
telephone contact or office visit.
All patients underwent transthoracic echocardiography
and Doppler studies. Two-dimensional images were ob-
tained from parasternal long- and short-axis, apical4-cham-
ber, and subcostal4-chamber views. Transthoracic echocar-
diograms were reviewed to assess the pericardium, valvular
anatomy and function, and cardiac function. Continuous-
wave Doppler was used to measure maximum jet velocity.
The left ventricular EF was calculated using biplane Simp-
son's methods; transvalvular pressure gradient was deter-
mined using the Bernoulli formula, and aortic valve area
was calculated using the continuity equation on the basis of
measurement of left ventricular outflow tract diameter in a
parasternal long-axis view for calculation of a circular
cross-sectional area, outflow tract velocity from an apical
approach using pulsed Doppler, and the maximum aortic jet
from the continuous-wave Doppler recording.
Right-sided cardiac catheterization was performed with a
7Fr Swan-Ganz catheter (Edwards Lifesciences, Irvine, Cal-
ifornia). We carefully measured right atrial pressures (am-
plitudes of a and v waves and mean pressure), right ven-
tricular systolic ,.and diastolic pressures, pulmonary artery
pressures (systolic, diastolic, and mean), and pulmonary
capillary wedge pressures (a and v waves and mean pres-
sure). Cardiac output was determined using the thermodi-
lution method. Left-sided cardiac catheterization was car-
ried out from the femoral artery. Aortic valve area was
calculated using the Gorlin formula.
The BA V procedure was performed according to stan-
dard techniques via the retrograde femoral approach. Hep-
arin (10 to 70 U/kg) was administrated in all patients after
insertion of an 8Fr to 13Fr sheath. Peak and mean gradients,
together with thermodilution cardiac outputs, were re-
corded. To stabilize the balloon position across the valve
before balloon inflation, the right ventricle was paced at a
high rate (180 to 200 beats/min) ·until the systemic blood
pressure decreased to <50 mm Hg. Pacing was continued
until the balloon was fully deflated.
SA VR was performed under standard anesthesia and
followed standard surgical techniques, extracorporeal cir-
culation, and myocardial protection methods. Patients
underwent anticoagulation using 3 mg/kg heparin sulfate
to maintain an activated clotting time of 2480 seconds.
Bioprostheses (Carpentier-Edwards Perimount Magna,
sizes 19 to 25 mm; Edwards Lifesciences) were implanted
and concomitant coronary artery bypass surgery was done
in 15 patients (45.4%).
The T A VI procedure was performed using the Edwards
Sapien (Edward Lifesciences) balloon-expandable prosthe-
sis. Overall, 21 patients (55.2%) received 23-mm valves and
17 patients (44.7%) received 26-mm valves. The procedures
were performed by the transfemoral approach in 26 (68.4%)
and by the transapical approach in 12 (31.6%). All proce-
dures were done under adjuvant transesophageal guidance.
Continuous variables are presented as mean ± SD and
categorical variables as percentages. Days of follow-up are
presented as median and interquartile intervals (25th to 75th
percentiles). Differences between continuous variables were
assessed using Student's t tests. Paired tests were analyzed
using paired Student's t tests. Categorical variables were
compared using chi-square or Fisher's exact tests as indi-
cated. Significance was set at p <0.05. Cumulative survival
curves were constructed using the Kaplan-Meier method
and compared using log-rank tests.
The effects of clinical characteristics, echocardiographic
and hemodynamic variables, and the type of treatment op-
tion were studied using multivariate logistic regression anal-
(p = (
o n l y ~
~ d u r e s
~ . 4 % )
Valvular Heart Disease/Aortic Stenosis and Low Ejection Fraction
Laboratory values, echocardiographic data, invasive hemodynamic data, and treatment of patients with high versus low transvalvular gradients
B-type natriuretic peptide (pg/ml)
Ventricular septal thickness (mm)
Aortic valve area (cm2)
Mean transvalvular aortic gradient (mm Hg)
Pulmonary artery systolic pressure (mm Hg)
Moderate to severe mitral regurgitation
Moderate to severe tricuspid regurgitation
Aortic valve area (cm2)
Mean gradients across aortic valve (mm Hg)
Pulmonary artery systolic pressure (mm Hg)
Pulmonary capillary wedge pressure (mm Hg)
Cardiac output (Limin)
EF after intervention
D. EF immediately after intervention (BAV, TAVI, or SAVR)
Data are expressed as mean ::': SD or as number (percentage).
ysis to identify variables associated with improvement in
theEF after BAV, SAVR, or TAVI.
Baseline clinical characteristics of low- and high-gradi-
ent patients are listed in Table 1. Those· with low gradients
were younger by 4 years (p <0.001) and more often had
coronary heart disease, as evidenced by more previous myo-
cardial infarctions (p = 0.01) and coronary bypass surgery
(p,<O.OOl). They also more often had renal insufficiency
(p ?' 0.03).
Table 2 compares the echocardiographic and hemody-
namic measurements of the 2 groups. Aortic valve area was
larger (p <0.001), while the EF and cardiac output were
lower (p <0.001 and p <0.04, respectively). Importantly,
pulmonary artery wedge pressure was similar between the 2
"groups. B-type natriuretic peptide was higher but not sig-
nificantly so in those with low gradients.
The treatment strategy used varied widely, but some
trends are notable, because the choice of therapy was asso-
ciated with outcome. Those with low gradients were· more
frequently treated medically (27% vs 9%, p <0.001) and
less commonly with T A VI compared to patients with
high gradients (9.4% vs 22%, p = 0.003). Importantly,
only 21.1% of this group underwent either form of valve
replacement compared to 35.0% of those in the high-
Peak Transvalvular Gradient (mm Hg)
(n = 170)
(n = 100)
36.0 ::': 4.9
11.7 ::': 1.7
1.8 ::': 1.4
1,920 ::': 1,330
35.2 ::': 4.6
11.5 ::': 1.6
1.6 ::': 1.3
1,503 ::': 1,141
26.4 ::': 6.9
1.25 ::': 0.2
0.80 ::': 0.16
3.3 ::': 0.5
27.6 ::': 8.9
48.9 ::': 15.8
30.5 ::': 6.6
1.33 ::': 0.27
0.66 ::': 0.17
4.2 ::': 0.6
47.3 ::': 13.8
54.1 ::': 16.3
0.73 ::': 0.23
27.2 ::': 9.4
54.6 ::': 15.6
223 ::': 8.8
3.7 ::': 1.1
0.53 ::': 0.18
58.2 ::': 12.7
57.5 ::': 15.4
22.5 ::': 8.5
4.1 ::': 1.3
(n = 91)
4.9 ::': 8.1
(n = 7 ~ )
Kaplan-Meier curves were used to compare overall sur-
vival for low- and high-gradient patients without regard to
treatment strategy (Figure 1). Those with low gradients (n =
92) had a mortality rate of 53.8% during a median follow-up
period of 151 days (interquartile range 55 to 348), and those
with high gradients had a mortality rate of 41% (n = 41)
during a median follow-up period of 246 days (interquartile
range 88 to 550) (p = 0.01).
Figure 2 illustrates survival curves comparing observa-
tions with regard to treatment modality. In those with med-
ical_therapy alone, the mortality rate was 56.3% (n = 31).
The ~ a d d i t i o n of BA V (n = 79) offered no advantage; sur-
vivalwas 54.8%. Mortality rate was significantly better in
the relatively small groups that underwent TAVI (n = 12
[31.5%]) and SAVR (n = 10 [30.3%]). Thus, those With
either form of valve replacement had significantly better
~ u r v i v a l than those with medical therapy alone or with BA V
plus medical treatment. The effects of patient selection for
SA VR and TAVI are the likely explanation.
Figure 3 illustrates the change in the EF after aortic valve
intervention. Of the 215 patients who had an intervention
(BAV, TAVI, or SAVR), echocardiographic follow-up was
available in 170 (79.0%). The low-gradient group at IJase-
line had significantly less improvement in the EF immedi-
ately after intervention compared to the high-gradient group
(4.9 ± 8.1% VS 9.3 ± 11.2%, p = 0.004).
EF improved immediately, with absolute increases
The American Journal of Cardiology (www.ajconline.org)
~ - -
P ~ O . O l
.. ·· ....
.. : .............. ..
.. ~ ! ......... ..
':, ... .. • ...... -............... .
'> • ............................ .....................
Low gradients (:540mmHg) (n=170)
-----· High gradients (>40mmHg) (n=lOO)
Patient at risk
Low cradlents 170
Hich cradients 100
Figure 1. Kaplan-Meier survival curves of low-gradient (::540 mm Hg) versus high-gradient (>40 mm Hg) patients.
>10%, in 28 patients (25.6%) after BAV, in 16 (66.6%)
after surgery, and in 28 (75.6%) after TAVI (p <0.001).
The beneficial effect on the EF of the relief of AS persisted
during intermediate and late follow-up (Figure 3). At 1
week, patients treated with BA V maintained a 4.0% in-
crease over baseline (p <0.001), those treated with SAVR
maintained a 9.2% increase (p <0.001), and those treated
with TAVI maintained a 14.4% increase (p <0.001). At the
last available follow-up (3 to 12 months), improvements
over baseline were observed in all 3 groups. The increments
over baseline were 7.9% for patients treated with BA V
(p <0.001), 11.9% for those with SA VR, and 20.0%
(p <0.001) for those with TA VI (Figure 3).
Factors associated with an improvement in the EF of
2:10% at 3 to 12 months are listed in Table 3. After adjust-
ment by means of a multivariate analysis limited to patients
who underwent procedures to relieve AS, the odds of im-
provement in thej:F were greatest for those who underwent
either surgery or TA VI (odds ratio 6.25, 95% confidence
interval2.2 to 16.6, p <0.001). In addition, the presence of
a high gradient before the procedure was independently
associated with improvement in the EF (odds ratio 2.2, 95%
confidence interval 1.1 to 4.4, p <0.03).
Our study confirms the limited life expectancy of pa-
tients (overall mortality of 50% at 2 years) who present with
severe AS and depressed left ventricular function, who are
at high risk for SAVR. In particular, the results of the study
demonstrate the adverse prognostic implications of patients
presenting with low transvalvular gradients ( <40 mm Hg),
who experienced an even higher mortality rate compared to
patients with higher transvalvular gradients.
A similar adverse prognostic impact of a low transval-
vular gradient has been noted by others. Previous reports
have cited not only a much greater perioperative risk4•5 but
also significantly compromised long-term survival. 6 In
Lund's 7 series of > 600 patients with severe AS, those with
low gradients had significantly worse survival.
In contrast, our data provide encouraging but indirect
evidence that when an intervention to relieve the AS can be
undertaken, a beneficial effect in this very ill patient subset
can be expected. In our patients, improvement in the EF was
observed immediately after SA VR and T A VI and was du-
rable (Figure 3), and SA VR or TAVI were associated with
improved survival (Figure 2).
It seems likely that those with transvalvular gradients
<40 mm Hg are fundamentally different from those with
gradients >40 mm Hg. It can be assumed that intrinsic
myocardial function was better in those whose myocardial
function was sufficient to generate wall tension and ejection
velocity adequate to produce larger gradient. That notion is
given credibility by the greater prevalence of conditions
likely to adversely affect left ventricular function (e.g.,
previous myocardial infarction, diabetes mellitus, and renal
dysfunction; Table 1) in the low-gradient group.
In addition, patients with low gradients had a greater
prevalence of moderate or severe mitral regurgitation (Table
Valvular Heart Disease/Aortic Stenosis and Low Ejection Fraction
~ - - - - - - - - - - - - - - - ·
· · - - · ~ , ______ ----..
" " ~ ~ ......
.. · .. ......
. . ...
.......................... !. ...................... -:. .................. ..
Surgical AVR (n=33)
Figure 2. Kaplan-Meier survival curves of patients on the basis of treatment: medical versus BA V versus TA VI versus SA VR.
20.0 11_" .. - · " - ~ ~ . - - ------- ,. ·--·----·· ___ ] ___ ··---· ----·-----·----. -··-
.... BAV (N=109)
_ ~ S u r g e r y ( N = 2 4 )
..... TAVI (N=37)
Figure 3. EF at baseline and after BAV, SAVR, and TAVI. 'Comparing baseline EF to EF at follow-up.
2). The regurgitation could compromise the ability of the
left ventricle to generate a stroke volume and therefore a
When neither SA VR nor TAVI was undertaken, mortal-
ity approached 55% at 1 year, which is significantly higher
than the approximately 30% found in patients who were
selected to undergo 1 of these valve replacement proce-
dures. Inevitably, selection bias existed. Patient selection
for SA VR and T A VI was unquestionably influenced by
factors not accounted for by either Society of Thoracic
Surgeons score or European System for Cardiac Operative
Risk Evaluation score. Those not accepted for T A VI or