Impact of transcatheter aortic valve implantation on coronary flow reserve by transthoracic Doppler echocardiography 1-year after the intervention in severe aortic stenosis patients

Background

Coronary flow reserve (CFR) which is one of indexes reflecting coronary microcirculation in patients without significant epicardial coronary lesions can be impaired in patients with severe aortic stenosis (AS). It has been shown that CFR is an independent predictor for future cardiovascular events in AS patients. Transcatheter aortic valve implantation (TAVI) has rapidly become widespread and is becoming the standard treatment for severe AS. This procedure may have a good effect on CFR due to reduction of severe afterload in patients with severe AS. Although the recent reports evaluated change in CFR immediately and 6 months after TAVI, it has not been evaluated whether impaired CFR improves 1-year after TAVI in AS patients with preserved left ventricular ejection fraction (LVEF).

Purpose

The purpose of the present study was to investigate whether impaired CFR improves 1-year after TAVI in severe AS patients with preserved LVEF.

Methods

The study population consists of consecutive 105 patients with severe AS undergoing TAVI. Exclusion criteria were atrial fibrillation, old myocardial infarction, history of coronary artery bypass grafting, significant lesions in the left anterior descending artery (LAD), moderate or severe mitral valve disease, history of valve replacement, LVEF <50% and preoperative CFR >2.2. CFR was obtained from coronary flow velocity by transthoracic echocardiography at rest and maximal hyperemia in LAD before, immediately and 1-year after TAVI. We compared CFR between before and after TAVI in the study patients who did not meet the exclusion criteria.

Results

After exclusion of 76 patients who met the exclusion criteria, the final study patients consist of 29 patients (8 male, 84.9±5.2 years). There was no significant difference in LVEF (61.3±3.4% vs 61.6±4.4%, P=0.667) and LV end-diastolic volume (LVEDVI; 58.2±9.2 mL/m2 vs 55.8±9.0 mL/m2, P=0.089) between before and immediately after TAVI. LVEF (61.0±2.8%, P=0.721) and LVEDVI (58.0±9.1 mL/m2, P=0.949) 1-year after TAVI were similar to those before TAVI. There was no significant difference in coronary flow velocity at rest between before and immediately after TAVI (27.4±8.9 vs 24.4±7.0 cm/s, P=0.051) and between before and 1-year after TAVI (25.9±8.3 cm/s, P=0.396). Coronary flow velocity at maximal hyperemia 1-year after TAVI significantly increased compared with that before TAVI (from 48.8±13.9 to 67.9±21.0 cm/s, P<0.001) while there was no significant difference between before and immediately after TAVI (52.0±12.0 cm/s, P=0.186). Impaired CFR before TAVI (1.82±0.28) increased immediately (2.03±0.39, P=0.009) and 1-year after TAVI (2.69±0.57, P<0.001).

Conclusions

The present results suggest that impaired CFR in patients with preserved LVEF improves 1-year after TAVI. TAVI may have a good effect on CFR in severe AS patients with preserved LVEF.

Funding Acknowledgement

Type of funding sources: None.

P1518 Relationship between post-operative asymptomatic status and reverse remodeling of large left atrium in patients with aortic stenosis who underwent aortic valve replacement

Introduction

Recently, we have reported that large left atrial volume (minimum left atrial volume index : LAVImin ≥30ml/m²) at end-diastole determined by direct exposure of left ventricular (LV) end-diastolic pressure can predict post-operative symptomatic status after aortic valve replacement (AVR) in aortic stenosis (AS) patients with high sensitivity and modest specificity. Reverse remodeling of large LAVImin after AVR may contribute to false positive for the prediction of post-operative symptomatic status in patients with AS.

Purpose

The purpose of this study was to evaluate relationship between post-operative symptomatic status and reverse remodeling of large LAVImin in patients with AS who underwent AVR.

Methods

The study population consisted of 75 patients with AS who underwent AVR and were followed up for 600 days after AVR, after the exclusion of the followings; atrial fibrillation, significant coronary artery disease, significant mitral valve disease, pacemaker rhythm, and inadequate echocardiographic images. We measured LAVImin by biplane Simpson"s method before and after AVR. Preoperative large LAVImin (≥30ml/m²) according to the previous study was observed in 32 (43%) of 75 patients. We divided these 32 patients into two groups according to the post-operative symptomatic status during the follow-up period.

Results

There was no significant difference in pre-operative LAVImin between patients with and without post-operative symptom (46.5 ± 13.4 vs 40.4 ± 8.6 ml/m²). On the other hand, post-operative LAVImin in patients without post-operative symptom was significantly smaller than that in patients with post-operative symptom (31.5 ± 8.6 vs 54.8 ± 14.0 ml/m², p < 0.01). While significant regression in LAVImin after AVR was observed in patients without post-operative symptom (40.4 ± 8.6 to 31.5 ± 8.6 ml/m², p < 0.05), no regression in LAVImin after AVR was observed in patients with post-operative symptom (46.5 ± 13.4 to 54.8 ± 14.0 ml/m²).

Conclusions

Reverse remodeling of large LAVmin in patients with AS who underwent AVR was observed in post-operative asymptomatic group, but not in symptomatic group. These results suggest that reverse remodeling of large LAVImin after AVR could contribute to the post-operative asymptomatic status in patients with AS who underwent AVR.

P91 Prognostic value of tissue-tracking mitral annular displacement by speckle-tracking echocardiography in asymptomatic patients with aortic stenosis with preserved left ventricular ejection fraction

Background

  Management of asymptomatic severe aortic stenosis (AS) patients with preserved left ventricular (LV) ejection fraction (EF) remains controversial. Recent studies using have shown that decreased LV longitudinal deformation assessed by global longitudinal strain analysis can predict adverse cardiac events in AS patients with preserved EF. Tissue-tracking mitral annular displacement (TMAD) by speckle-tracking echocardiography provides rapid and simple assessment of LV longitudinal deformation even when the acoustic window is poor (Fig.1).

Purpose

 The purpose of this study was to examine the value of TMAD to predict occurrence of the cardiac events in asymptomatic severe AS patients with preserved EF.

Methods

  We studied 103 patients with severe AS and preserved EF [aortic velocity >4m/s or aortic valve area (AVA) <1.0 cm2, EF >50%]in whom TMAD was measured, and a total of 44 patients were included in the final data setaccording to the exclusion criteria. Using TMAD analysis software, the base-to-apex displacement of automatically defined mid-point of mitral annular line in four-chamber view was quickly assessed, and the percentage of its displacement to LV length at end-diastole (%TMAD) was calculated (Fig.1). We investigated the association between %TMAD and the cardiac events including implementation of hospitalization due to heart failure, decreased EF (< 50%), aortic valve replacement or transcatheter aortic valve implantation due to appearance of symptoms and cardiac death, 

Results

 In all the final study patients, %TMAD was successfully and quickly (within 10 seconds) evaluated. During a follow-up, the cardiac events developed in 16 (36%) of 44 patients. Tableshows echocardiographic parameters in patients with and without the cardiac events. %TMAD was significantly impaired in patients with the cardiac events compared with those without the cardiac events (9.6 ± 0.6 vs 12.1 ± 0.4%, p= 0.002). The other parameters were not involved in the event occurrence; age, LV mass index, EF, aortic velocity, AVA, tricuspid regurgitation pressure gradient (TR-PG), early diastolic /atrial filling velocity (E/A), early diastolic velocity of the mitral valve annulus (e’) and E/e’. In multiple variable analysis, %TMAD was an independentpredictor of the cardiac events (HR; 12.1, p= 0.001). ROC analysis revealed that the area under the curve of %TMAD was 0.81 for the cardiac events. Kaplan-Meier analysis showed %TMAD (cut-off: 11.9) provides a significant difference in the cardiac event (Fig. 2). Conclusions.  The present results suggests that TMAD easily and rapidly estimated by speckle-tracking echocardiography can be used as a simple method to predict occurrence of the cardiac events in asymptomatic severe AS patients with preserved EF.

Abstract P91 Figure 1,2 and Table

P2700Impact of instantaneous wave-free ratio on graft failure after coronary artery bypass graft surgery

Background

It has been reported that preoperative fractional flow reserve (FFR) is associated with graft patency after coronary artery bypass graft (CABG) and the patency is excellent when a bypass graft is anastomosed on a vessel with positive FFR. However, the association with graft patency has not yet been investigated in its novel counterpart, instantaneous wave-free ratio (iFR), and iFR sometimes contradicts FFR results.

Purpose

The purpose of this study is to assess an impact of preoperative iFR on a graft failure after CABG in patients with coronary arteries showing positive FFR (≤0.80).

Methods

We retrospectively identified patients who had undergone preoperative coronary angiography in conjunction with resting and hyperemic intra-coronary pressure measurements, CABG, and graft evaluation by coronary computed tomography angiography. After excluding vessels with negative FFR (>0.80), vessels were divided into two groups: negative iFR group (iFR >0.89) and positive iFR group (iFR ≤0.89). The rate of graft failure within 1 year after CABG was compared between the two groups.

Results

We analyzed 131 vessels in 89 patients (35 vessels in the negative iFR group and 96 vessels in the positive iFR group). The negative iFR group showed significantly higher iFR (0.92±0.02 vs. 0.74±0.13, P<0.0001) and FFR (0.72±0.06 vs. 0.63±0.09, P<0.0001) than the positive iFR group, although percent diameter stenosis (%DS) was comparable (57±10 vs. 56±9, P=0.47). The graft failure significantly often occurred in the negative iFR group than in the positive iFR group (28.6% vs. 8.3%, P=0.0029). In order to reduce the imbalance in the baseline characteristics except for iFR, 70 vessels were selected by using propensity score matching (n=35 in each group). The propensity score matched vessels also demonstrated significantly higher rate of graft failure in the negative iFR group than in the positive iFR group (28.6% vs. 5.7%, p=0.026) despite much more balanced FFR (0.72±0.06 vs. 0.69±0.07, p=0.02) and %DS (57±10 vs. 57±9, p=1.000).

Conclusions

Even when FFR is positive, the graft failure is likely to occur when a bypass graft is anastomosed on a vessel with negative iFR compared to a vessel with positive iFR.

Acknowledgement/Funding

None

P3387Cholesterol crystals in superficial plaque layer detected by optical coherence tomography as a new morphological feature for plaque rupture

Background

While plaque rupture (PR) is the leading cause of acute myocardial infarction (AMI), other etiologies are also involved in the onset of AMI. Cholesterol crystals (CCs) are usually present abundantly in atherosclerotic plaques, especially in the culprit site of AMI. However, the relationship between in vivo CCs and PR is unclear. Optical coherence tomography (OCT) is a high-resolution imaging technique that allows for the in vivo identification of various plaque characteristics including PR and CCs.

Purpose

The aim of this study was to investigate prevalence and distribution of CCs between patients with AMI with PR, AMI without PR, and SAP.

Method

This study consisted of 146 patients with coronary artery disease (AMI with PR; n=64, AMI without PR; n=41, and SAP; n=41) who underwent OCT prior to percutaneous coronary intervention. Plaque characteristics in OCT images were assessed according to the consensus document. We classified the distribution of CCs as follows; superficial type CCs were defined by any of the CCs invading the fibrous cap and remaining CCs as deep type CCs.

Result

There was no statistical difference in clinical characteristics among the three groups. The % diameter stenosis was significantly smaller in the SAP group than others (AMI with PR 91±12% vs. AMI without PR 86±13% vs. SAP 65±9%, p<0.001). The prevalence of CCs was significantly higher in the AMI with PR group than others (AMI with PR 78% vs. AMI without PR 41% vs. SAP 39%, p<0.001). The prevalence of superficial type CCs was significantly different among the groups (AMI with PR 72% vs. AMI without PR 24% vs. SAP 7%, p<0.001). Multivariable logistic analysis demonstrated that lipid plaque (OR 84.5, 95% CI [6.30–11332.33], p<0.001) and superficial type CC (OR 9.5, 95% CI [2.61–34.89], p<0.001) were independent predictors of PR.

Conclusion

Plaque with CCs invading the fibrous cap is frequently associated with PR in patients with AMI, suggesting. In vivo CC detection is a new morphological feature for plaque rupture.

Acknowledgement/Funding

This study was supported by a grant from JSPS KAKENHI (17K09557).

P3365Relationship between early diastolic intra-ventricular pressure gradient shortly after aortic valve closure estimated by vector flow mapping and left ventricular diastolic untwisting rate in humans

Background

Early diastolic suction is an important determinant of early diastolic function. Previous studies using color Doppler M-mode and speckle-tracking echocardiography have shown left ventricular (LV) early diastolic LV untwisting rate is directly related to LV intra-ventricular pressure gradient (IVPG) between LV base and apex during early diastole. Recent introduction of vector flow mapping (VFM) using combination of color Doppler and speckle-tracking echocardiography provides noninvasive and feasible assessment of early diastolic IVPG shortly after aortic valve closure including isovolmic relaxation period (ED-IVPG) in humans. However, relationship between VFM–derived ED-IVPG and early diastolic LV untwisting rate has not been well investigated.

Purpose

The purpose of this study was to examine relationship between ED-IVPG estimated by VFM and LV untwisting rate by speckle-tracking echocardiography.

Methods

The study population consists of 66 patients without segmental wall motion abnormality, significant valvular diseases, and atrial fibrillation who underwent echocardiography for evaluation of LV function (age: 60±15 years, LVEF: 49±16%). From the apical long-axis views by color Doppler echocardiography, we analyzed peak ED-IVPG between LV base and apex just after aortic valve closure (figure) using commercially available VFM analysis software (DAS-RS1, Hitachi). We assessed peak early diastolic LV untwisting rate and LV torsion from LV basal and apical short-axis view by speckle-tracking echocardiography. We evaluated correlation between ED-IVPG and LV untwisting rate. We also evaluated correlation between ED-IVPG and peak systolic LV torsion, LV end-diastolic (EDV) and end-systolic volumes (ESV), ejection fraction (EF), early diastolic velocity (E) of LV inflow, average early diastolic velocity (e') of mitral annulus, and average E/e'.

Results

In all the study patients, ED-IVPG was successfully and quickly evaluated. 1) ED-IVPG correlated well with peak LV untwisting rate (r=0.64, p<0.0001). 2) ED-IVPG significantly correlated with LV torsion, LVEDV, LVESV, and LVEF (r=0.47, r=−0.48, r=−0.46, and r=0.48, respectively, p<0.001). 3) There were no significant correlations between ED-IVPG and other indexes including E, average e', and average E/e'. According to receiver operating characteristic analysis, the best cut-off value of ED-IVPG for determining impaired LV untwisting rate (<80 degrees/s) was found at 0.42 mmHg (sensitivity 81%, specificity 76%, and area under the curve 0.86)

ED-IVPG measurement by VFM

Conclusions

The present results showed that noninvasive VFM-derived peak ED-IVPG shortly after aortic valve closure is related to early diastolic peak LV untwisting rate. ED-IVPG easily and quickly estimated by VFM may be used as an additional index for LV diastolic function.

P2453Value of pre-operative left atrial minimum volume as a surrogate for post-operative symptoms in patients with aortic stenosis who underwent aortic valve replacement

Background

Previous reports have shown that symptoms after aortic valve replacement (AVR) are not uncommon depending on severity of myocardial fibrosis in patients with severe aortic stenosis (AS). Pre-operative minimum left atrial volume (LAVmin) at end-diastole determined by direct exposure of left ventricular end-diastolic pressure may be used as a surrogate for post-operative symptoms in patients with severe AS undergoing AVR.

Purpose

The purpose of this study was to examine the value of pre-operative echocardiographic LAVmin index (LAVImin) to predict post-operative symptomatic status after AVR in patients with severe AS.

Methods

The study population consisted of 219 patients with severe AS who underwent AVR and were followed up for 1000 days after AVR. Pre-operative maximum LAV index (LAVImax), LAVImin, LA emptying fraction (LAEF), LV volume indexes, LV ejection fraction (LVEF) by biplane Simpson's method, aortic valve area index (AVAI), mean aortic valve pressure gradient (mAV-PG), E/A, mean E/e' from LV inflow and mitral annular velocity, and pulmonary artery systolic pressure (PASP) were evaluated by Doppler echocardiography.

Results

After exclusion of 136 patients who met the exclusion criteria (atrial fibrillation, significant coronary artery disease, significant mitral valve diseases, pacemaker rhythm, and inadequate echocardiographic images), the final study population consisted of 75 patients (75±7 years old, 46 female). During a follow-up, 19 patients (25%) complained post-operative symptoms. There were no significant differences in pre-operative serum hemoglobin, creatinine, BNP, chronic obstructive pulmonary disease, hypertension, diabetes, LV volume indexes, LVEF, AVA, mAV-PG between patients with and without post-operative symptoms. There were significant differences in pre-operative LAVImax, LAVImin, and LAEF between patients with and without post-operative symptoms. (60±15 vs 47±15 ml/m2, 45±15 vs 28±1 ml/m2, and 29±12 vs 42±11 ml/m2, respectively). E/A, mean E/e', and PASP in patients with symptoms were significantly greater compared with patients without symptoms (1.0±0.3 vs 0.7±0.2, 25±3 vs 18±2, 44±17 vs 32±9 mmHg, respectively). In the multivariate analysis, pre-operative LAVImin was the independent predictor of the post-operative symptomatic status after AVR (odds ratio: 1.11, 95% confidence interval: 1.04 - 1.18). Receiver operating characteristic analysis revealed that area under the curve (AUC) of LAVImin (cutoff: 30ml/m2) for post-operative symptoms was the largest (0.84) among the other echocardiographic parameters, and significantly larger than that of mean E/e' (0.67, *p<0.01) and LVEF (0.53, **p<0.05) (figure).

Figure 1. ROC analysis

Conclusions

The present results suggest that pre-operative echocardiographic LAVImin may be used as a surrogate for post-operative symptomatic status after AVR in patients with severe AS.

P4349Simple and rapid estimation of left ventricular longitudinal deformation by tissue-tracking mitral annular displacement in single apical view

Background

Noninvasive assessment of left ventricular (LV) deformation using global longitudinal strain (GLS) has prognostic value in patients with and without preserved ejection fraction (EF). Application of speckle-tracking technology to the mitral annulus provides rapid and easy assessment of displacement of septal and lateral mitral annulus and mid-point of mitral annular line in single apical view (TMAD) even in poor echo-image quality. TMAD may be used as a simple index of LV longitudinal deformation in patients with and without preserved EF (Figure).

Purpose

The purpose of this study was to examine whether TMAD can be used as a simple index of LV longitudinal deformation in patients with and without preserved EF.

Methods

The study population consists of 95 patients without segmental wall motion abnormality, significant valvular diseases, and atrial fibrillation in whom both TMAD and GLS measurements were applied by QLAB software (Philips). We estimated GLS from apical 4- and 2-chamber views and apical longitudinal views, and TMAD from apical 4-chamber view. TMAD was automatically and quickly evaluated as the base-to-apex displacement of septal (TMADsep), lateral (TMADlat), and mid-point of annular line (TMADmid) (Figure). The percentage of M-TMAD to LV length from the mid-point of mitral annuls to the apex at end-diastole (%TMADmid) was also calculated. We compared each TMAD values with GLS values by linear regression analysis, and evluated TMAD values by a receiver operating characteristic (ROC) analysis to detect impaired LV longitudinal deformation (|GLS|<12.0%).

Results

TMAD was successfully assessed in 94 of 95 patients (99%) while GLS was measured in 84 of 95 patients (87%, p=0.0082 vs TMAD). There were good correlations between each TMAD index and |GLS| (TMADsep:r=0.77, TMADlat:r=0.81, TMADmid:r=0.82, %TMADmid:r=0.87). According to ROC curve, the best cut-off values for TMADsep, TMADlat, TMADmid, and %TMADmid in determining LV longitudinal deformation were 6.8mm, 8.0mm, 7.8mm, and 9.5% respectively (Table).

Conclusions

The present results suggest that rapid and easy assessment of TMAD in single apical view may be used as a simple index of LV longitudinal deformation.