Circulation Journal
Online ISSN : 1347-4820
Print ISSN : 1346-9843
ISSN-L : 1346-9843
Imaging
Effect of Diastolic Flow Reversal Patterns on Clinical Outcomes Following Transcatheter Aortic Valve Implantation ― An Intraprocedural Echocardiography Study ―
Masashi OtaMasaki IzumoYasuhide MochizukiHaruka NishikawaYukio SatoMika WatanabeToshiki KaiharaKazuaki OkuyamaRyo KamijimaYasuhiro TanabeTomoo HaradaToshiro ShinkeYoshihiro J Akashi
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2021 Volume 85 Issue 7 Pages 1068-1075

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Abstract

Background: Although diastolic flow reversal (DFR) in the descending aorta, assessed via transesophageal echocardiography (TEE), is a simple and easy indicator for evaluating aortic regurgitation, the association between DFR pattern and clinical outcomes following transcatheter aortic valve implantation (TAVI) is unclear. The purpose of this study was to evaluate the effect of DFR patterns on clinical outcomes following TAVI.

Methods and Results: Two-hundred and eleven patients (mean age, 83.6±5.7 years; 69% female) who underwent TAVI were retrospectively assessed via intraprocedural TEE. DFR was evaluated using pulsed-wave Doppler in the descending aorta before and after TAVI. The primary endpoint was major adverse cardio-cerebrovascular events (MACCEs). Although only 7 patients (3.3%) had moderate or severe paravalvular leak, as assessed by color Doppler echocardiography, holo-DFR (HDFR) was observed in 33 patients (16.0%) after TAVI. MACCEs occurred in 40 patients during the median follow up of 282 days (interquartile range: 160–478 days). The estimated cumulative MACCE-free survival at 1 year was significantly lower in patients with HDFR than in those without HDFR. A Cox proportional hazards analysis revealed that HDFR after TAVI was independently associated with MACCEs.

Conclusions: HDFR was associated with an increased risk of MACCEs after TAVI. DFR evaluated by intraprocedural echocardiography could serve as a simple and easy method for predicting clinical outcomes.

The incidence of aortic stenosis is increasing in developed countries with aging societies.1 Transcatheter aortic valve implantation (TAVI) is a safe and minimally invasive treatment for aortic stenosis, and the number of TAVI procedures performed is increasing worldwide.24 Although various prognostic factors following TAVI have been reported, few reports have focused on the prediction of outcomes using intraprocedural echocardiography. Diastolic flow reversal (DFR) in the descending aorta, assessed via transesophageal echocardiography (TEE), is a simple and easy indicator of aortic regurgitation (AR).57 However, the changes in DFR patterns before and after TAVI and the association between DFR patterns and clinical outcomes following TAVI are unclear. The purpose of this study was to assess the changes in DFR pattern using intraprocedural TEE before and after TAVI, and to evaluate the prognostic effect of DFR pattern on clinical outcomes following TAVI.

Methods

Study Population

This study reviewed 255 consecutive patients with severe aortic stenosis who underwent TAVI under general anesthesia from April 2016 to December 2018 at St. Marianna University Hospital, Japan. We excluded 44 patients who did not have TEE images, and 211 patients were finally included. This study protocol was approved by the St. Marianna University ethics committee. All patients agreed to participate in the study and written informed consent was given by all patients. The investigation was performed according to the Declaration of Helsinki.

Intraprocedural TEE

We performed intraprocedural TEE using an iE33 ultrasound system equipped with an X7-2t TEE ultrasound probe (Philips Medical Systems, Andover, MA, USA). DFR was assessed using pulsed-wave Doppler in the descending aorta before and after the deployment of the prosthetic valve. All procedures were performed without the insertion of a wire into the left ventricle (LV). For the pulsed-wave Doppler spectra from the descending aorta, a sample volume was placed proximally or distally to be aligned as much as possible along the long axis of the aorta where color Doppler reflux of the descending aorta was suspected in the periphery of 80–110 imaging sector arcs. The Doppler filter was decreased to approximately 20–30 cm/s to allow the detection of low velocities. We defined 3 categories of DFR based on the flow reversal velocities as follows: absent DFR, with <50% flow reversal; intermediate DFR, with >50% flow reversal but without complete flow reversal; and holo-DFR (HDFR), with complete DFR (Figure 1). DFR was diagnosed by 2 cardiologists (MO and MI). We also measured the circumferential extent of the jet, which only extended beyond the left ventricular outflow tract in the short-axis view with color Doppler, with a Nyquist limit of >50 cm/s.8 Color gain settings were optimized to eliminate random color in areas with outflow. According to the Valve Academic Research Consortium (VARC-2) criteria, the severity of paravalvular leak (PVL) defined the following with respect to the circumferential extent of paravalvular AR in the short axis: mild (<10%), moderate (10–29%), and severe (≥30%).

Figure 1.

Three types of diastolic flow reversal (DFR). (Left) Absent DFR, (Middle) Intermediate DFR, (Right) Holo-diastolic flow reversal (Holo-DFR).

Transthoracic Echocardiography

Comprehensive transthoracic echocardiography, including 2D and Doppler echocardiography, was performed according to the American Society of Echocardiography guidelines9 in all patients using a commercially available ultrasound system within 1 month before TAVI. LV end-diastolic volume (EDV) and end-systolic volume (ESV) were measured using Simpson’s biplane method. LV ejection fraction was calculated using the following formula: [(EDV − ESV) / EDV] × 100. Continuous-wave Doppler was used to measure the maximal aortic valve velocities in apical 3 or 5-chamber views, and the peak and mean gradients were estimated based on the simplified Bernoulli equation. LV outflow tract (LVOT) diameter was measured using parasternal long-axis views. LVOT velocities were acquired using pulsed-wave Doppler, and the velocity time integrals (VTILVOT) were measured. LV stroke volume was calculated using the following formula: (LVOT diameter / 2)2 × 3.14 × VTILVOT. Aortic valve area (AVA) was calculated with the continuity equation and the AVA index was also calculated, divided by body surface area.

Assessment of Clinical Outcomes

Follow-up data were collected from medical records. The primary endpoint of this study was major adverse cardio-cerebrovascular events (MACCEs, defined as all-cause death, myocardial infarction, stroke, or rehospitalization for heart failure).

Statistical Analysis

All continuous variables are shown as mean and standard deviation. Comparisons between groups were performed with 1-way analysis of variance, unpaired Student’s t-test, Fisher’s exact test, or a Bonferroni test for continuous variables, and with the chi-squared test for categoric variables. Associations between predictors and events were formally tested using a Cox proportional hazards model with regression analysis. The patients were divided into 2 groups for the log-rank test, with the construction of Kaplan-Meier curves. Statistical analysis was performed with SPSS for Windows, version 20 (SPSS Inc., IBM, Armonk, NY, USA). A P value of <0.05 was considered significant.

Results

Clinical and Echocardiographic Characteristics

The baseline characteristics of the study patients are shown in Table 1. The mean patient age was 83.6±5.7 years, 69% were women, and the mean Society of Thoracic Surgeons score was 5.7%. Of the patients included in this study, 96% underwent TAVI via a femoral approach and 85% received a balloon-expandable valve. Although only 7 patients (3.3%) had moderate or severe PVL, as assessed by color Doppler echocardiography, HDFR was observed in 33 patients (16.0%) after TAVI. There were no significant differences in clinical characteristics except in chronic kidney disease (CKD) between patients with and without HDFR. A summary of the echocardiographic findings before and after TAVI are shown in Table 2. Patients with HDFR had a larger left atrial volume index and AVA index, and higher E wave velocity than patients without HDFR. With regard to post-TAVI echocardiographic parameters, patients with HDFR were more likely to have moderate or greater PVL than those without HDFR, but other parameters did not significantly differ between the groups.

Table 1. Baseline Characteristics of Study Patients
  All
(n=211)
HDFR after TAVI (+)
(n=33)
HDFR after TAVI (−)
(n=178)
P value
Age, years 83.6±5.71 84.5±5.2 83.4±5.8 0.15
Female 146 (69.1) 22 (67) 124 (70) 0.37
Body surface area, m2 1.45±0.20 1.45±0.21 1.45±0.20 0.45
Hypertension 169 (80.1) 26 (79) 143 (80) 0.40
Diabetes mellitus 46 (21.8) 7 (21) 39 (22) 0.46
Hypercholesterolemia 97 (46) 15 (45) 82 (46) 0.46
Previous myocardial infarction 8 (3.8) 1 (3.0) 7 (3.9) 0.40
Previous PCI 42 (19.9) 8 (24.2) 34 (19.1) 0.22
Previous CABG 8 (3.8) 2 (6.1) 6 (3.4) 0.25
CKD 145 (68.7) 28 (84.8) 117 (65.7) 0.03
Ischemic cardiomyopathy 11 (5.2) 2 (6.1) 9 (5.1) 0.40
Atrial fibrillation 63 (30) 14 (42) 49 (28) 0.05
Systolic blood pressure, mmHg 135.3±22.3 140.3±14.8 135.1±22.6 0.29
Diastolic blood pressure, mmHg 65.8±12.3 65.5±8.2 65.8±13.4 0.48
Heart rate, beats/min 68.2±12.3 67.2±8.2 68.2±12.4 0.42
STS score, % 5.72±3.20 5.36±3.37 5.82±3.16 0.23
NYHA class III/IV 45 (21.3) 6 (18.2) 39 (21.9) 0.32
Access site
 Femoral 203 (96.2) 31 (93.9) 172 (96.6) 0.23
 Others 8 (3.8) 2 (6.1) 6 (3.4)
Prosthesis type
 Balloon-expandable 183 (86.7) 28 (84.8) 155 (87.1) 0.36
 Self-expandable 28 (13.3) 5 (15.2) 23 (12.9)
Prosthesis size (mm)
 20 18 (8.5) 2 (6.1) 16 (9.0)  
 23 107 (50.7) 18 (54.5) 89 (50)  
 26 65 (30.8) 8 (24.2) 57 (32.0)  
 29 21 (10.0) 5 (15.2) 16 (9.0)  

Data are expressed as mean±SD or n (%). CABG, coronary artery bypass grafting; CKD, chronic kidney disease; HDFR, holo-diastolic flow reversal; NYHA class, New York Heart Association functional classification; PCI, percutaneous coronary intervention; STS score, Society of Thoracic Surgeons score; TAVI, transcatheter aortic valve implantation.

Table 2. Echocardiography Findings Before and After TAVI
  All HDFR after TAVI (+) HDFR after TAVI (−) P value
Before TAVI
 LVDd 4.24±1.44 4.33±1.38 4.23±1.44 0.32
 LVDs 2.87±1.91 2.91±1.75 2.87±1.94 0.41
 EDV 80.9±30.9 84.3±30.7 80.2±30.7 0.24
 ESV 31.4±22.7 32.5±19.6 31.2±23.1 0.38
 LVEF 63.4±10.8 63.1±11.8 63.4±10.6 0.45
 SVi 29.7±16.6 28.3±10.7 30.0±17.5 0.59
 LAVi 55.4±30.6 68.5±56.2 52.9±21.8 0.003
 RVSP 31.6±10.4 35.1±12.5 30.9±9.70 0.02
 E 84.5±32.8 94.7±43.5 81.9±29.8 0.008
 E/A 1.26±6.24 0.83±0.46 0.78±0.40 0.28
 E/e’ 19.4±11.9 20.5±11.5 19.2±11.9 0.27
 AVA 0.60±0.17 0.63±0.22 0.60±0.15 0.09
 AVAi 0.41±0.12 0.45±0.15 0.41±0.11 0.03
 PV 4.29±1.00 4.19±1.05 4.31±1.00 0.27
 Mean PG 44.4±21.5 43.1±22.5 44.6±21.2 0.36
After TAVI
 LVEF 63.2±9.17 62.9±9.15 63.4±9.23 0.84
 EOAi 0.96±0.25 1.00±0.25 0.95±0.25 0.25
 PV 2.34±0.51 2.22±0.51 2.36±0.51 0.2
 Mean PG 12.0±5.4 10.6±5.1 12.2±5.4 0.14
 PPM 15 (7.1) 1 (3) 14 (7.9) 0.19
 PVL ≥moderate 7 (3.3) 4 (12) 3 (1.2) 0.001

Data are expressed as mean±SD or n (%). A, peak mitral velocity of the late filling wave; AVA, aortic valve area; AVAi, aortic valve area index; E, peak mitral velocity of the early rapid filling wave; e’, early diastolic mitral annular velocity; EDV, end-diastolic volume; EOAi, effective orifice area index; ESV, end-systolic volume; HDFR, holo-diastolic flow reversal; LAVi, left atrial volume index; LVDd, left ventricular end-diastolic diameter; LVDs, left ventricular end-systolic diameter; LVEF, left ventricular ejection fraction; PG, pressure gradient; PPM, prosthesis-patient mismatch; PV, peak velocity; PVL, paravalvular leak; RVSP, right ventricular systolic pressure; SVi, stroke volume index; TAVI, transcatheter aortic valve implantation.

The changes in DFR before and after TAVI are shown in Figure 2. Fifty-five patients (26.1%) had worsening DFR after TAVI. A comparison of clinical and echocardiographic indices between patients with and without worsening DFR is shown in Tables 3 and 4. The worsening DFR group was associated with the less frequent use of the balloon-expandable transcatheter heart valve compared with the non-worsening DFR group, but there was no significant difference in other clinical characteristics between the 2 groups. Preoperative echocardiographic parameters showed that patients with worsening DFR had a smaller stroke volume index than those without worsening DFR, but other parameters were not significantly different. Postoperative echocardiography showed that the peak velocity and mean pressure gradient tended to be lower in the patients with worsening DFR than in the patients without worsening DFR.

Figure 2.

Changes in DFR types before and after TAVI. Fifty-five patients (26.1%) of the study patients had worsening DFR after TAVI. DFR, diastolic flow reversal; TAVI, transcatheter aortic valve implantation.

Table 3. Comparisons of Clinical Characteristics Between Patients With and Without Worsening DFR
  Worsening DFR (+)
(n=55)
Worsening DFR (−)
(n=156)
P value
Age (years) 83.7±5.8 83.6±5.7 0.42
Female 22 (67) 124 (70) 0.13
Body surface area, cm2 1.47±0.18 1.44±0.21 0.18
Hypertension 44 (80) 125 (80) 0.49
Diabetes mellitus 13 (24) 33 (21) 0.35
Hypercholesterolemia 22 (40) 75 (48) 0.15
Previous myocardial infarction 3 (5.5) 5 (3.2) 0.22
Previous PCI 12 (21.8) 30 (21.2) 0.17
Previous CABG 3 (5.5) 8 (5.1) 0.34
CKD 44 (80) 101 (64.7) 0.21
Ischemic cardiomyopathy 4 (7.3) 7 (4.5) 0.21
Atrial fibrillation 21 (38.2) 42 (26.9) 0.14
Systolic blood pressure, mmHg 140.4±22.5 135.0±22.2 0.27
Diastolic blood pressure, mmHg 68.7±14.9 65.6±13.1 0.27
Heart rate, beats/min 76.1±18.6 67.7±11.6 0.04
STS score, % 5.62±3.21 5.80±3.21 0.36
NYHA class III/IV 8 (14.5) 37 (23.7) 0.07
Access site
 Femoral 52 (94.5) 151 (96.8) 0.23
 Others 3 (5.5) 5 (3.2)
Prosthesis type
 Balloon expandable 43 (78.2) 140 (89.7) 0.02
 Self-expandable 12 (21.8) 16 (10.3)
Prosthesis size (mm)
 20 3 (5.5) 17 (10.9)
 23 26 (47.3) 81 (51.9)
 26 18 (32.7) 47 (30.1)
 29 8 (14.5) 13 (8.3)

Data are expressed as mean±SD or n (%). DFR, diastolic flow reversal. Other abbreviations as in Table 1.

Table 4. Comparisons of Echocardiography Findings Between Patients With and Without Worsening DFR
  Worsening DFR (+) Worsening DFR (−) P value
Before TAVI
 LVDd 4.33±1.42 4.22±1.35 0.20
 LVDs 2.97±2.31 2.84±1.96 0.24
 EDV 84.1±35.7 79.7±28.7 0.21
 ESV 33.9±29.1 30.6±19.7 0.21
 LVEF 62.2±11.1 63.7±10.7 0.19
 SVi 26.1±9.19 31.0±18.4 0.01
 LAVi 56.2±21.8 55.0±33.0 0.38
 RVSP 33.0±10.1 31.1±10.4 0.11
 E 86.3±32.8 83.5±32.8 0.30
 E/A 0.79±0.34 0.78±0.42 0.48
 E/e’ 19.1±9.80 19.5±12.5 0.41
 AVA 0.60±0.18 0.60±0.16 0.33
 AVAi 0.42±0.12 0.41±0.11 0.31
 PV 4.18±0.96 4.32±1.00 0.17
 Mean PG 42.3±20.3 45.1±21.7 0.19
After TAVI
 LVEF 61.9±9.53 63.7±9.06 0.23
 EOAi 0.97±0.24 0.95±0.26 0.59
 PV 2.12±0.49 2.41±0.50 0.001
 Mean PG 9.88±4.37 12.7±5.56 0.001
 PPM 3 (5.5) 12 (7.7) 0.23
 PVL ≥moderate 2 (3.6) 5 (3.2) 0.43

Data are expressed as mean±SD or n (%). DFR, diastolic flow reversal. Other abbreviations as in Table 2.

Clinical Outcomes

Over a median follow up of 282 days (interquartile range: 160–478 days) after TAVI, a total of 40 (19.0%) patients developed MACCEs. Kaplan-Meier analysis revealed that patients with HDFR after TAVI had a significantly lower event-free survival rate compared to those without HDFR (hazard ratio [HR]: 3.31; 95% confidence interval [CI]: 1.56–6.23, log-rank P=0.001, Figure 3B). Similarly, patients with worsening DFR had a lower event-free survival rate than those without worsening DFR (HR: 3.23; 95% CI: 1.74–6.01; P=0.0003, Figure 3C). Moreover, we additionally compared clinical outcomes of patients who transitioned from absent to intermediate (33 patients) to those of patients with no change or improvement of DFR. In the Kaplan-Meier analysis, patients with transition from absent to intermediate were shown to have a significantly worse prognosis than patients with no change or improvement of DFR (log-rank P=0.02, Figure 3D); similarly, in the Cox proportional hazards regression analysis, transition from absent to intermediate was shown to be statistically significantly associated with worse prognosis (HR: 2.46 [1.14–5.30], P=0.02). Table 5 shows both the univariate and multivariate Cox proportional-hazards analyses for the prediction of the clinical outcomes. In multivariate analysis, preprocedural LV ejection fraction and intraprocedural echocardiography findings of HDFR and worsening DFR were independent predictors of clinical outcomes after TAVI.

Figure 3.

Kaplan-Meier curve estimates of major adverse cardio-cerebrovascular events (MACCEs) for HDFR and worsening DFR. There was no difference in the MACCE-free survival rate between patients with and without HDFR (A), but the MACCE-free survival rate was lower in patients with HDFR than in those without HDFR after TAVI (B). The MACCE-free survival rate was lower in patients with worsening DFR than in those without worsening DFR (C). Patients with transition from absent to intermediate DFR were also shown to have a significantly worse prognosis than patients with no change or improvement of DFR (D). DFR, diastolic flow reversal; HDFR, holo-diastolic flow reversal; TAVI, transcatheter aortic valve implantation.

Table 5. Univariate and Multivariate Cox Proportional Hazards Analysis for Predicting Clinical Outcomes
Covariate Univariate analysis Multivariate analysis model 1 Multivariate analysis model 1
HR 95% CI P value HR 95% CI P value HR 95% CI P value
Clinical characteristics
 Age (years) for increase 1.11 1.03–1.20 0.01 1.05 0.99–1.22 0.06 1.05 0.99–1.22 0.06
 Female 0.61 0.33–1.13 0.12            
 Height (cm) for increase 0.99 0.98–1.02 0.73            
 Weight (kg) for increase 0.98 0.95–1.00 0.08            
 CKD 3.29 1.29–8.40 0.01 1.5 0.96–2.37 0.07 1.5 0.96–2.37 0.07
 STS score 1.00 0.91–1.10 0.98            
 Prosthesis type (balloon-expandable) 0.19 0.03–1.40 0.11            
Preprocedural echocardiography findings
 SVi for increase 1.01 0.99–1.02 0.41            
 EF for increase 0.96 0.94–0.98 0.002 0.96 0.94–0.99 0.03 0.96 0.94–0.99 0.03
 AVAi 0.96 0.68–1.35 0.73            
 Peak velocity 0.82 0.60–1.20 0.2            
 Mean PG 0.99 0.98–1.01 0.21            
Intraprocedural echocardiography findings
 HDFR (before TAVI) 0.77 0.30–1.99 0.59            
 HDFR (after TAVI) 3.31 1.56–6.23 0.0002 1.98 1.02–3.91 0.04      
 Worsening 3.23 1.74–6.01 0.0003       2.71 1.41–5.25 0.003

Hazard ratio (HR) and 95% confidence interval (CI) for risk of major adverse cardio-cerebrovascular events. Abbreviations as in Tables 1,2.

Discussion

The main findings of this study are as follows: (1) HDFR was noted in 16% of the patients immediately after TAVI; (2) 26% of the patients had worse DFR patterns after TAVI; and (3) both HDFR and worse DFR patterns were predictors of clinical outcomes following TAVI. To our knowledge, this study is the first study to investigate the relationship between changes in DFR before and after TAVI and prognosis.

Relationship Between DFR and AR

Generally, DFR is considered to reflect blood flow in the aorta during diastole and is caused by significant AR; DFR has been used to diagnose the severity of AR.57,10,11 Several studies using transthoracic echocardiography reported that HDFR in the abdominal aorta was useful for diagnosing significant AR. Mihara et al12 reported that HDFR after TAVI is useful for PVL diagnosis in a study using intraprocedural TEE. In our study, PVL evaluation using color Doppler showed a rate of ~3% for moderate or high PVL, as noted in the PARTNER II study,13 whereas HDFR was noted in 16% of cases after TAVI. Deviations were noted in the evaluation; however, the consistency between AR severity assessment and DFR with color Doppler before TAVI was high. The reason for this is that the mechanism of HDFR development may be influenced not only by AR, but also by reflected waves in the increase of arterial stiffness associated with aging and arteriosclerosis. Among the 88 patients who underwent carotid-ankle vascular index (CAVI) before TAVI in this study, the HDFR group tended to have higher CAVI than the non-HDFR group (9.37±1.85 vs. 8.66±2.02, P=0.08). Hashimoto and Ito reported that HDFR was strongly associated with arterial stiffness,14,15 especially CKD16 and impaired left ventricular diastolic function.17 Also in this study, the HDFR group had a significantly higher rate of CKD (84.8% vs. 65.7% , P=0.03) and a significantly worse left ventricular diastolic dysfunction (E wave velocity: 84.5±32.8 cm/s vs. 94.7±43.5 cm/s, P=0.008; left atrial volume index: 55.4±30.6 vs. 68.5±56.2, P=0.003; systolic pulmonary artery pressure: 31.6±10.4 mmHg vs. 35.1±12.5 mmHg, P=0.02) compared with the non-HDF group. From these results, it is considered that the arteriosclerosis is related to the factor in which HDFR appears in spite of not recognizing PVL. In addition, it is considered that HDFR manifested in the absence of AR due to increased cardiac output after TAVI for aortic stenosis, with increased arterial stiffness.

Association Between DFR and Prognosis

There are 2 reasons why DFR is associated with heart failure. The first is the effects of acutely aggravated AR. Patients with aortic stenosis who have afferent hypertrophy find it challenging to cope with a sudden increase in volume load, and the acutely increased AR is thought to affect post-TAVI heart failure.8 Some studies have reported associations between moderate and severe PVL after TAVI and patient prognoses,18,19 and cases without AR before TAVI were reported to be particularly affected. In our study, not only HDFR after TAVI but also changes in DFR were also associated with prognosis, which seems to support the results of these previous studies. HDFR is also associated with elevated central blood pressure, and central blood pressure has been reported to be more closely correlated with myocardial infarction, cerebral infarction, and readmission than brachial blood pressure.15 The presence of HDFR has also been linked to stroke and cardiovascular events, regardless of AR.14,20,21

Clinical Implication

As TAVI expands into low-risk patients, more sophisticated treatment and patient management are required. After TAVI, DFR can help determine patient outcomes. In the case of HDFR after TAVI, the degree of PVL should first be carefully evaluated by color Doppler or aortic imaging. If a significant PVL is observed, additional extension should be considered in order to reduce PVL. Assessing post-TAVI DFR can also help with post-TAVI patient management. The careful follow up of patients with HDFR, despite the absence of significant PVL, is required, and active intervention should be considered in the presence of cardiovascular risk factors such as hypertension, diabetes, hyperlipidemia, and a sedentary lifestyle.

Study Limitations

Although our study had a sufficient number of cases and a high follow-up rate for a prognostic study, it was a single-center retrospective study with a follow-up period of 2 years (medium-term follow up). Regarding the accuracy and reproducibility of DFR, our study showed that although the error between examiners was as low as 2.8%, the speed of the color Doppler was reduced to ~10–20 cm/s, and the position of the sample volume of the pulsed-wave Doppler was carefully adjusted. These parameters need to be selected and evaluated based on the particular setting. Moreover, DFR is affected by hemodynamics such as hypotension and bradycardia; therefore, it is necessary to perform TAVI with stable hemodynamics during TAVI. In this study, we used intraprocedural TEE to evaluate DFR, but some patients cannot undergo TEE, such as those under local anesthesia or those with gastrointestinal disorders;12,22 however, DFR can be fully evaluated on transthoracic echocardiograms;23,24 further study is necessary in this regard.

Conclusions

HDFR and a worsening DFR pattern were associated with increased risk of MACCEs following TAVI. DFR evaluated by intraprocedural echocardiography was a simple and easy method for predicting clinical outcomes.

Disclosures

Y.J.A. is a member of Circulation Journal’s Editorial Team. M.I. received lecture fees from Edwards Lifesciences.

Conflict of Interest / Acknowledgements

None.

IRB Information

The present study was approved by St. Marianna University School of Medicine ethics committee (Reference number: 4320).

References
 
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