Surgical vs Transcatheter Aortic Valve Replacement in Patients With a Low Ejection Fraction

Abstract

Currently, there is no preference for surgical (SAVR) vs transcatheter (TAVR) aortic valve replacement in patients with low ejection fraction (EF). The present study retrospectively compared the outcomes of SAVR vs TAVR in patients with EF ≤40% (70 SAVR and 117 TAVR patients). Study outcomes were survival and the composite endpoint of stroke, aortic valve reintervention, and heart failure readmission. The patients who had TAVR were older (median: 75 (25-75th percentiles: 69-81) vs 51 (39-66) years old; P < .001) with higher EuroSCORE II (4.95 (2.99-9.85) vs 2 (1.5-3.25); P < .001). Postoperative renal impairment was more common with SAVR (8 (12.5%) vs 4 (3.42%); P = .03), and they had longer hospital stay [9 (7-15) vs 4 (2-8) days; P < .001). There was no difference between groups in stroke, reintervention, and readmission (Sub-distributional Hazard ratio: .95 (.37-2.45); P = .92). Survival at 1 and 5 years was 95% and 91% with SAVR and 89% and 63% with TAVR. Adjusted survival was comparable between groups. EF improved significantly (β: .28 (.23-.33); P < 0.001) with no difference between groups (P = .85). In conclusion, TAVR could be as safe as SAVR in patients with low EF.

Keywords

surgical aortic valve replacement transcatheter aortic valve replacement low ejection fraction

Introduction

Left ventricular dysfunction increased the risk of surgical aortic valve replacement (SAVR) in patients with severe aortic stenosis.¹ However, SAVR had survival advantages in those patients compared with medical therapy.² The effect of low ejection fraction (EF) on the outcomes after transcatheter aortic valve replacement (TAVR) is controversial.³ TAVR offered comparable outcomes in patients with low and preserved left ventricular function.⁴

There is a lack of studies comparing SAVR and TAVR in patients with low EF, and there is no consensus on the recommended approach in those patients. Therefore, the present study compared hospital and mid-term outcomes, including survival, aortic valve reintervention, stroke, and readmission for heart failure in patients with an EF of ≤40% who underwent SAVR vs TAVR.

Methods

Design and Patients

We conducted a retrospective study that included 187 patients who underwent SAVR (n = 70) or TAVR (n = 117) at Prince Sultan Cardiac Center, Riyadh, Saudi Arabia. Patients who had SAVR were operated upon from 2002 to 2019, and TAVR was performed from 2009 to 2019. We included patients who had isolated aortic valve intervention with an EF ≤40%. Patients who had concomitant cardiac surgery or transcatheter intervention were excluded from our study. Patient assignment to each group was based on the Heart Team discussion and was based on patient risk stratification according to Euro SCORE II.⁵

The Ethical Committee of Prince Sultan Cardiac Center approved data collection for this study (Reference number R19021); the need for patient consent was waived because of the retrospective design.

Study Data and Outcomes

Patient data were retrieved from the electronic and paper charts and the prospectively maintained TAVR registry. We compared demographic data, comorbidities, and laboratory data between groups. Operative data included operative urgency, valve type, and size.

Hospital outcomes were stroke, renal impairment, myocardial infarction (MI), postoperative atrial fibrillation (AF), permanent pacemaker (PPM) insertion, bleeding, hospital stay, and all-cause mortality. Long-term outcomes were survival and the composite endpoint of aortic valve reintervention, readmission for heart failure, and stroke.

Follow-Up

Patients had postoperative echocardiographic follow-ups according to the discretion of the treating physicians. There were 538 echocardiographic follow-ups available for all patients over a 5 year period. The changes in EF were traced longitudinally and compared between both groups. Patients were contacted by phone in June 2021 to confirm their vital status.

Definitions

A reduced EF was defined as an EF ≤40%.^6,7 Hospital outcomes were defined as those occurring during hospital admission or within 30 days from the procedure. Postoperative myocardial infarction (MI) was diagnosed with a pathological Q-wave, left bundle branch block, or angiographic evidence of coronary occlusion.⁸ Postoperative renal impairment was defined as a 1.5-time increase in serum creatinine.⁹ Preoperative variables were collected according to Euro SCORE II definitions.⁵

Statistical Analysis

Continuous data were presented as median and interquartile range or mean and standard deviation. The student t-test was used to compare normally distributed continuous data and the Wilcoxon test was used for non-normal data. Categorical data were presented as frequencies and percentages and compared with the Chi-square or Fisher exact test. Time to event data was plotted using a Kaplan-Meier curve and compared between groups with the log-rank test. Univariable competing risk regression was used to assess the effect of the intervention on the composite endpoint of stroke, aortic valve reintervention, and admission for heart failure in the presence of death as a competing factor. Risk factors for mortality were evaluated using multivariable Cox regression analysis. Univariable Cox regression was used, and variables with a P < .15 were entered into a stepwise multivariable regression with a backward selection with a stay P < .1. Factors included in the multivariable regression were age, gender, creatinine clearance, hypertension, diabetes mellitus, previous myocardial infarction, previous percutaneous coronary intervention, preoperative mitral stenosis, extracardiac arteriopathy, left ventricular end-diastolic and end-systolic diameters, indexed left ventricular mass and the intervention group. Collinearity was tested with variance inflation factor (VIF), and all variables had a VIF <1.5. Random effect regression was used to compare the change in the EF between groups. Stata 16 (Stata Corp. College Station, TX, USA) was used for all analyses.

Results

Baseline Data

The patients who had TAVR were significantly older, with significantly more females. Diabetes, hypertension, previous myocardial infarction (MI), extracardiac arteriopathy, and heart failure were more common in TAVR patients. Creatinine clearance was significantly lower in TAVR patients (Table 1).

Table 1.

Comparison of Baseline Demographic and Clinical Preoperative Data in Surgical and Transcatheter Aortic Valve Replacement.

	SAVR (n = 70)	TAVR (n = 117)	P
Age (years)	51 (39-66)	75 (69-81)	<.001
Male	61 (87.1%)	85 (72.6%)	.02
BMI (kg/m²)	27 (22.9-31.1)	27.6 (24.1-31.2)	.50
NYHA 3 or 4	53 (75.7%)	109 (93.2%)	.001
Euro SCORE II	2 (1.5-3.25)	4.95 (2.99-9.85)	<.001
Atrial fibrillation	5 (7.5%)	9 (7.7%)	.95
PPM	0 (.0%)	4 (3.42%)	.58
Hypertension	36 (54.6%)	88 (75.21%)	.004
DM	19 (28.79%)	71 (60.68%)	<.001
COPD	4 (6.15)	14 (11.97)	.30
Stroke	6 (8.96%)	12 (10.26%)	.80
Previous MI	3 (4.29%)	19 (16.2%)	.01
Extracardiac-arteriopathy	0	13 (11.1%)	.01
Poor mobility	4 (6.06%)	12 (10.26%)	.42
HF in the past 2 weeks	8 (12.31%)	44 (37.6%)	<.001
PCI	1 (1.47%)	35 (29.9%)	<.001
Smoking	10 (15.9%)	4 (3.42%)	.006
Creatinine (μmol/l)	95 (81-110%)	94 (77-119)	.74
Creatinine clearance (mL/min)	83 (59- 99)	58 (42.7-74)	<.001
Bilirubin (μmol/l)	8 (6-13)	10 (6-13)	.39
Hemoglobin ((g/dl)	13.40 ± 2.05	12.40 ± 1.84	.001
Echocardiographic data
Ejection fraction (%)	32.5 (25-40)	30 (25-40)	.06
LVEDD (mm)	62.5 (57.5-69)	53 (49-59)	<.001
LVESD (mm)	48 (43-58)	42 (36-47)	<.001
PASP (mmHg)	63.93 ± 9.61	53.52 ± 6.94	<.001
Indexed LV mass (g/m²)	191.05 ± 64.98	125.75 ± 30.03	<.001
AV peak gradient (mmHg)	60 (25-82)	66.35 (53.65-80.9)	.01
Aortic valve area (cm²)	.65 (.51-.95)	.65 (.52-.78)	.68
AR grade			<.001
0	11 (15.71%)	33 (28.21%)
I	8 (11.43%)	50 (42.74%)
II	10 (14.29%)	28 (23.93%)
II	0	1 (.85%)
IV	41 (58.57%)	5 (4.27%)
AS grade			<.001
0	27 (38.57%)	10 (8.55%)
I	6 (8.57%)	1 (.85%)
II	3 (4.29%)	5 (4.27%)
III	4 (5.71%)	13 (11.11%)
IV	30 (42.86%)	88 (75.21%)
MR grade			<.001
0	12 (20%)	8 (6.96%)
I	39 (65%)	43 (37.39%)
II	9 (15%)	49 (42.61%)
III	0	11 (9.57%)
IV	0	4 (3.48%)
MS grade			.13
0	53 (94.64%)	76 (82.61%)
I	3 (5.36%)	10 (10.87%)
II	0	5 (5.43%)
III	0	0
IV	0	1 (1.09%)
TR grade			<.001
0	29 (55.77%)	9 (7.83%)
I	16 (30.77%)	43 (37.39%)
II	7 (13.46%)	48 (41.74%)
III	0	11 (9.57%)
IV	0	4 (3.48%)

Continuous data are presented as mean ± SD or median (25-75th percentiles) and categorical data as number and percent. AR: aortic regurgitation; AS: aortic stenosis; AV: aortic valve; BMI: body mass index; DM: diabetes mellitus; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; LVESD: left ventricular end-systolic diameter; NYHA: New York heart association; COPD=chronic obstructive pulmonary disease; MI: myocardial infarction; MR: mitral regurgitation; MS: mitral stenosis; HF: heart failure; CABG: coronary artery bypass grafting; PCI: percutaneous; PASP: pulmonary artery systolic pressure; PPM: permanent pacemaker; TR: tricuspid regurgitation

Aortic valve regurgitation was more prevalent in the SAVR group. Patients who underwent TAVR had a higher prevalence of aortic stenosis, concomitant mitral valve regurgitation and stenosis, and tricuspid valve regurgitation. Patients in the SAVR group had significantly higher left ventricular end-diastolic and end-systolic diameters and pulmonary artery systolic pressure (Table 1).

Operative Data

Six patients had prior cardiac surgery in the SAVR group (SAVR = 5 and coronary artery bypass grafting (CABG) = 1) and 19 in the TAVR group (SAVR = 1, CABG = 16, and combined SAVR and CABG = 2). There was no difference in operative urgency between groups, and the valve size was significantly larger in TAVR patients. Ischemic time was 72 (25-75th percentiles: 60-91) minute and cardiopulmonary bypass time was 93 (80.5-111) minute in SAVR patients. In the TAVR group, Sapien 3 (Edwards Lifesciences, Irvine, CA) was used in 29 patients and CoreValve (Medtronic, Inc, Minneapolis, MN) in 85 patients (Table 2).

Table 2.

Comparison of Operative Data Between Surgical vs Transcatheter Aortic Valve Replacement.

	SAVR (n = 70)	TAVR (n = 117)	P
Re-operative surgery	6 (8.57%)	19 (16.24%)	.14
Operative urgency
Elective	68 (97.14%)	112 (95.7%)	.71
Emergency	2 (2.86%)	5 (4.3%)	.71
Valve type
Bioprosthetic	34 (48.6%)	117 (100%)	<.001
Mechanical	36 (51.43%)	0 (.0%)	<.001
Valve size (mm)	23.4 ± 2.05	27.3 ± 2.9	<.001

Continuous data are presented as mean ±SD or median (25-75^th percentiles) and categorical data as number and percent. SAVR: surgical aortic valve replacement; TAVR: transcatheter aortic valve replacement.

Hospital Outcomes

There were no differences in stroke, myocardial infarction, and hospital mortality between groups. Postoperative renal impairment and prolonged hospital stay were more common in SAVR patients. Grade I paravalvular leak was significantly higher in the TAVR group. Permanent pacemaker insertion was non-significantly higher in the TAVR group (Table 3). Three patients in the SAVR group required re-exploration for bleeding, and 25 patients in the TAVR group had minor bleeding at the access site. Nineteen patients in the TAVR group had vascular complications at the access site, and no vascular complications were reported in the SAVR group.

Table 3.

Comparison of Hospital Outcomes Between Surgical (SAVR) vs Transcatheter Aortic Valve Replacement (TAVR).

	SAVR (n = 70)	TAVR (n = 117)	P
New onset atrial fibrillation	6 (9.23%)	4 (3.42%)	.17
PPM insertion	3 (4.55%)	15 (12.82%)	.12
Stroke	0 (.0%)	1 (.85%)	>0.99
Renal impairment	8 (12.5%)	4 (3.42%)	.03
Hospital stay duration (days)	9 (7-15)	4 (2-8)	<.001
Myocardial infarction	1 (1.64%)	0 (.0%)	.34
Paravalvular leak grade
0	68 (97.14%)	71 (60.68%)	<.001
I	2 (2.86%)	45 (38.46%)
II	0	1 (.85%)
Mortality	1 (1.6%)	6 (5.13%)	.42

Continuous data are presented as mean ± SD or median (25-75th percentiles) and categorical data as number and percent. SAVR: surgical aortic valve replacement; TAVR: transcatheter aortic valve replacement.

Long-Term Outcomes

The median follow-up was 30 (15-72) months [73.5 (27-135) months in the SAVR group and 26 (12- 39) months in the TAVR group]. The composite endpoint of stroke, aortic valve reintervention, and readmission for heart failure occurred in 13 patients. Heart failure admission occurred in 2 patients in the SAVR group and 6 in the TAVR group, stroke occurred in 4 patients in the SAVR group and 4 in TAVR, and aortic valve reintervention was required in 4 patients in the SAVR group (redo SAVR = 3, valve-in-valve = 1) and no patients in the TAVR group.

Competing risk regression of the composite endpoint (stroke, aortic valve reintervention, and readmission for heart failure) and in the presence of death as a competing risk factor elucidated no difference between both groups (Sub-distributional Hazard Ratio (SHR): .95 (95% CI: .37-2.45); P = .92). There was no difference between groups regarding the composite endpoint (Figure 1).

Figure 1.

The freedom from heart failure admission, aortic valve reintervention, and stroke in patients with surgical and transcatheter aortic valve replacement (SAVR: surgical aortic valve replacement; TAVR: transcatheter aortic valve replacement).

Mortality occurred in 34 patients (8 in the SAVR group and 26 in the TAVR group). Survival at 1, 3, and 5 years was 95%, 93%, and 91% in the SAVR group and 89%, 80%, and 63% in the TAVR group (log-rank P < .001) (Figure 2). Predictors of mortality were low creatinine clearance, diabetes mellitus, previous PCI, recent heart failure, and preoperative mitral stenosis. There was no difference in survival between SAVR and TAVR groups in the multivariable regression analysis (Table 4).

Figure 2.

Kaplan-Meier survival curve in patients who had surgical vs transcatheter aortic valve replacement (SAVR: surgical aortic valve replacement; TAVR: transcatheter aortic valve replacement).

Table 4.

Predictors of Long-Term Mortality After Surgical and Transcatheter Aortic Valve Replacement.

	HR (95% CI)	P
Mitral stenosis	2.48 (1.44-4.27)	.001
Recent heart failure	2.64 (1.03-6.78)	.043
Creatinine clearance	.97 (.56-.99)	.006
Previous PCI	2.92 (1.1-7.77)	.032
Diabetes mellitus	3.12 (1.14-8.57)	.027

CI: confidence interval; HR: hazard ratio; PCI: percutaneous coronary intervention.

Change in EF

There was significant improvement in the EF postoperatively (β: .28 (95% CI: .23- .33); P < .001) and the aortic valve intervention did not affect the change in EF (β: −.24 (95% CI: −2.75-2.27); P = .85) (Figure 3).

Figure 3.

The change in the mean ejection fraction during 3-year follow-up after surgical and transcatheter aortic valve replacement (SAVR: surgical aortic valve replacement; TAVR: transcatheter aortic valve replacement).

Discussion

Low EF is associated with increased postoperative morbidity and mortality in cardiac surgery patients.^10,11 Additionally, low EF was found as a risk factor for 30-day mortality in patients undergoing aortic valve replacement for severe aortic stenosis.¹² Despite that, SAVR was associated with good long-term outcomes with the recovery of ventricular function and functional class.^13,14

TAVR was presented as an attractive alternative to SAVR, and the indications were expanded to include low-risk patients.¹⁵ The benefits vs the risks of TAVR in patients with low EF are controversial. Low EF (˂40%) was a predictor of early mortality in patients who underwent TAVR in the Italian registry.¹⁶ Urena and associates, in a study of 3726 TAVR patients, found that low EF (≤40%) was an independent predictor of death during a 2-year follow-up.¹⁷ In contrast to these studies, the Placement of AoRTic TraNscathetER Valve Trial (PARTNER trial) did not elucidate a significant effect of low EF on TAVR or SAVR outcomes.¹⁸

There is a lack of studies comparing SAVR and TAVR in patients with low EF. In this study, we compared 70 patients who had SAVR and 117 patients who had TAVR, and all patients had isolated procedures with an EF ≤40%. In our series, SAVR patients were significantly younger; however, the age of TAVR patients was comparable with other trials.¹⁵ Comorbidities were more prevalent in TAVR patients and were of moderate and high risk according to Euro Score.⁵ The valve size was significantly bigger with TAVR, similar to other studies.¹⁹ SAVR had a more postoperative renal impairment and longer hospital stay, with no difference in stroke and hospital mortality between groups. In a meta-analysis comparing SAVR and TAVR, there were no differences in 30-day mortality, stroke, acute kidney injury, and myocardial infarction between groups.²⁰

We did not find a difference between groups in the composite endpoint of heart failure readmission, aortic valve reintervention, and stroke. Survival was better in SAVR; however, after adjusting baseline data, the aortic valve replacement approach did not affect survival. In a meta-analysis of SAVR and TAVR in intermediate and low-risk patients, no difference in 30-day, 1-, 2-, and 3-years mortality between groups.²¹ The authors also did not find a difference in stroke and aortic valve reintervention in a 3-year follow-up.

In our study, EF improved significantly in both groups during follow-up, and the most noticeable improvement occurred during the first year after the intervention. Robiolio and colleagues found a significant improvement in EF after SAVR in a 6-months follow-up.²² Recovery of left ventricular function was observed to occur for many years after SAVR.²³ Similar findings were observed after TAVR with immediate improvement of EF, especially in patients with low EF.²⁴ Moreover, TAVR improved EF in low flow and low gradient patients with impaired ventricular function.⁴

A budget impact analysis was conducted in Saudi Arabia and included our institution comparing TAVR vs SAVR. The study reported cost savings with TAVR. However, the study reported the 5-year cost only, and it was not limited to patients with low EF.²⁵

The major limitations of the study are the retrospective design and the lack of randomization. Patients were assigned to each group based on their characteristics, which led to significant variations in the baseline characteristics. The study outcomes could have been affected by patient characteristics. However, we adjusted the patient characteristics and found no difference in survival. On the other hand, other events had low frequency, and multivariable analysis was not feasible.

TAVR could be considered as safe as SAVR in patients with low EF. The EF improved significantly and similarly with both approaches.

Footnotes

Author Contributions

All authors contributed to: (1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data, (2) drafting the article or revising it critically for important intellectual content, and, (3) final approval of the version to be published.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Amr A. Arafat

Monirah A. Albabtain

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