Munenori Okubo

Evaluation of Left Atrial Degeneration for the Prediction of Atrial Fibrillation Usefulness of Integrated Backscatter Transesophageal Echocardiography

OBJECTIVES The purpose of this study was to elucidate the usefulness of integrated backscatter (IBS) transesophageal echocardiography (TEE) for the evaluation of atrial degeneration and clarify whether atrial degeneration predicts the occurrence of atrial fibrillation (AF). BACKGROUND One of the causes of AF is pathological degeneration of the left atrium (LA). However, there is no appropriate method to evaluate degeneration of the LA in the clinical setting. METHODS The IBS images were acquired with TEE with a 4- to 7-MHz transducer. The IBS values were calculated as the average power of the backscattered signal from regions of interest (ROI). In the pathological study, we measured IBS values of 21 left atrial specimens obtained from 10 autopsied hearts. Relative interstitial area in the ROI was automatically calculated by a personal computer. In the clinical study, we measured IBS values of the entire LA wall at 5-mm intervals (except the posterior wall) in 42 patients (18 non-AF patients, 14 paroxysmal AF patients, and 10 chronic AF patients). Each IBS value was color-coded to construct 3-dimensional maps. RESULTS There was a weak correlation between the relative interstitial area and IBS values (r = 0.45, p = 0.038). Average corrected IBS values of total voxels in color-coded maps in the AF group (24.4 +/- 6.4 dB) and the paroxysmal AF group (23.9 +/- 9.6 dB) were significantly greater than those in the non-AF group (15.6 +/- 7.4 dB, p = 0.007), whereas there was no significant difference in LA diameter between the paroxysmal AF group (39.4 +/- 6.5 mm) and the non-AF group (36.7 +/- 5.5 mm). CONCLUSIONS With IBS-TEE, we can identify an increase in atrial degeneration that might predict the occurrence of AF before LA dilation.

Transcatheter embolization by autologous blood clot is useful management for small side branch perforation due to percutaneous coronary intervention guide wire

A 75-year-old man underwent PCI for a bifurcation lesion with 90% stenosis in segment 6 and 75% proximal stenosis in segment 9 of the left coronary artery. We implanted a Duraflex coronary stent into segment 6 and kissing balloon inflation for segments 6 and 9. Although these 2 lesions were adequately dilated, we noticed coronary perforation caused by the guide wire in a small branch of segment 9. We tried to repair the perforation using a small balloon and long inflation, but unfortunately the perforation was not improved. We attempted to occlude the small branch including the perforation site with an autologous blood clot via a wire microcatheter inserted into the small branch. The autologous blood clot was suspended in contrast media and saline. Using this procedure, the small branch of segment 9 was occluded completely and the perforated site was repaired. After the procedure, no significant CPK elevation was detected, and 6 months later, we confirmed that small branch embolization was improved and coronary flow was good. Autologous blood clot is useful to occlude and repair perforations in small side branches of the coronary artery without myocardial damage.

Left atrial pathological degeneration assessed by integrated backscatter transesophageal echocardiography as a predictor of progression to persistent atrial fibrillation: Results from a prospective study of three-years follow-up

BackgroundIt is recognized that one of the causes of atrial fibrillation (AF) is pathological degeneration of the left atrium (LA). However, prospective study that elucidated the relationship between the incidence of persistent AF and pathological degeneration has not been performed. The purpose of this study was to elucidate the usefulness of integrated backscatter (IBS) values for the prediction of progression from paroxysmal AF (PAF) to persistent AF.MethodsWe measured IBS values of the entire LA wall at 5 mm intervals (except the posterior wall) in 27 patients with paroxysmal AF and evaluated progression to persistent AF for three years. IBS values were acquired with transesophageal echocardiography (TEE) using a 4–7 MHz transducer. IBS values were calculated as the average power of the backscattered signal from regions of interest (ROI). Each IBS value was color-coded to construct three dimensional maps.ResultsAverage IBS values of total voxels in color-coded maps in the persistent AF group were significantly greater than those in the non-persistent AF group (25.8 ± 5.0 dB vs. 17.4 ± 10.2 dB, p = 0.047), whereas there was no significant difference in LA diameter between the persistent AF and the non-persistent AF group. There was significant difference in persistent AF-free survival after the baseline measurements in the subjects stratified by IBS value (<20 dB versus ≥20 dB) (univariate Cox regression analysis: hazard ratio: 8.74, p =0.046).ConclusionUsing IBS values measured by TEE, we can identify an increase in atrial degeneration that may predict the occurrence of persistent AF before LA dilation.

Relationship among coronary plaque compliance, coronary risk factors and tissue characteristics evaluated by integrated backscatter intravascular ultrasound

BackgroundThe purpose of the present study was to evaluate the mechanical properties of coronary plaques and plaque behavior, and to elucidate the relationship among tissue characteristics of coronary plaques, mechanical properties and coronary risk factors using integrated backscatter intravascular ultrasound (IB-IVUS).MethodsNon-targeted plaques with moderate stenosis (plaque burden at the minimal lumen site: 50-70%) located proximal to the site of the percutaneous coronary intervention target lesions were evaluated by IB-IVUS. Thirty-six plaques (less calcified group: an arc of calcification ≤10°) in 36 patients and 22 plaques (moderately calcified group: 10° < an arc of calcification ≤60°) in 22 patients were evaluated. External elastic membrane volume (EEMV) compliance, lumen volume (LV) compliance, plaque volume (PV) response (difference between PV in systole and diastole), EEM area stiffness index were measured at the minimal lumen site. Relative lipid volume (lipid volume/internal elastic membrane volume) was calculated by IB-IVUS.ResultsIn the less calcified group, there was a significant correlation between EEMV compliance and the relative lipid volume (r = 0.456, p = 0.005). There was a significant inverse correlation between EEM area stiffness index and the relative lipid volume (p = 0.032, r = −0.358). The LV compliance and EEM area stiffness index were significantly different in the diabetes mellitus (DM) group than in the non-DM group (1.32 ± 1.49 vs. 2.47 ± 1.79%/10 mmHg, p =0.014 and 28.3 ± 26.0 vs. 15.7 ± 17.2, p =0.020). The EEMV compliance and EEM area stiffness index were significantly different in the hypertension (HTN) group than in the non-HTN group (0.77 ± 0.68 vs. 1.57 ± 0.95%/10 mmHg, p =0.012 and 26.5 ± 24.3 vs. 13.0 ± 16.7, p =0.020). These relationships were not seen in the moderately calcified group.ConclusionThe present study provided new findings that there was a significant correlation between mechanical properties and tissue characteristics of coronary arteries. In addition, our results suggested that the EEMV compliance and the LV compliance were independent and the compliance was significantly impaired in the patients with DM and/or HTN. Assessment of coronary mechanical properties during PCI may provide us with useful information regarding the risk stratification of patients with coronary heart disease.

Comparison between integrated backscatter intravascular ultrasound and 64-slice multi-detector row computed tomography for tissue characterization and volumetric assessment of coronary plaques.

BackgroundThe purpose of this study was to determine the cut-off values of Hounsfield units (HU) for the discrimination of plaque components and to evaluate the feasibility of measurement of the volume of plaque components using multi-detector row computed tomography (MDCT).MethodsCoronary lesions (125 lesions in 125 patients) were visualized by both integrated backscatter intravascular ultrasound (IB-IVUS) and 64-slice MDCT at the same site. The IB values were used as a gold standard to determine the cut off values of HU for the discrimination of plaque components.ResultsPlaques were classified as lipid pool (n =50), fibrosis (n =65) or calcification (n =35) by IB-IVUS. The HU of lipid pool, fibrosis and calcification were 18 ± 18 HU (−19 to 58 HU), 95 ± 24 HU (46 to 154 HU) and 378 ± 99 HU (188 to 605 HU), respectively. Using receiver operating characteristic curve analysis, a threshold of 50 HU was the optimal cutoff values to discriminate lipid pool from fibrosis. Lipid volume measured by MDCT was correlated with that measured by IB-IVUS (r =0.66, p <0.001), whereas fibrous volume was not (r =0.21, p =0.059).ConclusionLipid volume measured by MDCT was moderately correlated with that measured by IB-IVUS. MDCT may be useful for volumetric assessment of the lipid volume of coronary plaques, whereas the assessment of fibrosis volume was unstable.

Post-cardiac injury syndrome after a simple coronary stenting.

AbstractAn 80-year-old male patient underwent a coronary angioplasty without signs of complications. The day after the procedure, the patient complained of chest pain. The electrocardiogram showed a widespread ST segment elevation. A chest X-ray revealed pulmonary congestion with pleural effusion. There was no significant pericardial effusion detected with an echocardiogram. An administration of diuretics was initiated. After he showed an improvement of symptoms, the administration of diuretics was tapered. However, a deterioration of the oxygenation level was re-observed. The echocardiogram confirmed a cardiac tamponade at this time. The oxygenation level recovered after pericardiocentesis and pleurocentesis. Post-cardiac injury syndrome was suspected to be the cause of this clinical course, and the patient was given an intravenous administration of hydrocortisone followed by an oral administration of prednisone. All clinical parameters started to improve drastically.

CRT-300.02 Longitudinal Distribution of Lipid-rich Plaque Components in Culprit Lesions: A Near-infrared Spectroscopy Study

The near-infrared spectroscopy (NIRS) catheter system identifies lipid core-containing coronary plaques (LCP) of interest in the coronary arteries. We sought to evaluate axial distance in location between the maximum LCP site and the site that had the most luminal-narrowing as assessed by NIRS

In vivo tissue characterization of human atherosclerotic plaques by optical coherence tomography: A directional coronary atherectomy study with histopathologic confirmation

BACKGROUND The histopathological validation of optical coherence tomography (OCT) in visualizing atherosclerotic plaques has been reported only in ex vivo studies. We sought to evaluate the accuracy of OCT in tissue characterization in vivo. METHODS AND RESULTS A total of 25 patients with stable angina pectoris who underwent directional coronary atherectomy (DCA) were included in the investigation, whereby OCT was performed before and after a single debulking. The debulked region was determined on OCT and classified into fibrous tissue, lipid, calcification, thrombus, and macrophage accumulation, which were compared with histology. Changes in OCT signal intensity in the deeper intimal region after DCA were also visually evaluated. Fibrous tissues were detected in all cases, while thrombus was identified only in 1 case, by both OCT and histology. The sensitivity, specificity, positive and negative predictive values, and predictive accuracy for lipid detection by OCT were 88.9%, 75.0%, 66.7%, 92.3%, and 80.0%; those for calcification were 50.0%, 100%, 100%, 91.3%, and 92.0%; and those for macrophage accumulation were 85.7%, 88.9%, 75.0%, 94.1%, and 88.0%, respectively. The false positive diagnoses for lipid were mostly attributed to the extracellular matrix accumulation containing less collagen. The false negative diagnoses for calcification were explained by the presence of lipid around the calcification. The OCT signal intensity in the deeper intimal region substantially increased after DCA in all cases. CONCLUSIONS The current study showed excellent predictive accuracy of in vivo OCT in tissue characterization, whereas the limitations of OCT were highlighted by an over-detection of lipid, under-detection of calcification, and underestimation of the deeper intimal matrix.

Residual pressure gradient across the implanted stent: An important factor of post-PCI physiological results

BACKGROUND Instantaneous wave-free ratio (iFR) has the potential to improve the accuracy of the prediction of the physiological result of percutaneous coronary intervention (PCI). The aim of this study was to evaluate the accuracy of iFR to predict the final physiological results following PCI, and investigate the factors for failed prediction. METHODS In 73 lesions, iFR pullback recordings were measured and comparisons were made between the predicted improvement following PCI and the observed result. RESULTS iFR predicted-observed difference was 0.036±0.037. Multivariate analysis showed residual iFR pressure gradient across the implanted stent (odds ratio, 2.329; 95% confidence interval, 1.408-3.853; p=0.0010) as an independent risk factor for error in iFR prediction. CONCLUSIONS iFR predicted-observed difference was 0.036±0.037. Residual in-stent iFR pressure gradient following PCI is the only independent risk factor for failed prediction.

Postocclusional Hyperemia for Fractional Flow Reserve After Percutaneous Coronary Intervention

Background— Postocclusional hyperemia caused by balloon occlusion is a potential alternative method of inducing hyperemia for measuring post-percutaneous coronary intervention fractional flow reserve (FFR). The aim of this study was to investigate postocclusional hyperemia as a method of inducing hyperemia. Methods and Results— FFR measured by postocclusional hyperemia (FFRoccl) caused by balloon occlusion after percutaneous coronary intervention was compared with FFR measured by drug-induced hyperemia (FFR measured by intravenous ATP; and FFR measured by intracoronary papaverine injection [FFRpap]) in 98 lesions from 98 patients. The hyperemia duration was also measured for FFRoccl and FFRpap. The correlation coefficient between FFRoccl, FFR measured by intravenous ATP (r=0.973; P<0.01), and FFRpap (r=0.975; P<0.01) showed almost identical values to those obtained for the correlation coefficient between FFR measured by intravenous ATP and FFRpap (r=0.967; P<0.01). No clear difference was observed on Bland–Altman analysis. Hyperemia duration was significantly longer with FFRoccl than with FFRpap (70±22 versus 51±25 s; P<0.01). Conclusions— Strong correlations were found between FFRoccl and FFR measured by intravenous ATP and FFRoccl and FFRpap. Hyperemia caused by FFRoccl was significantly longer than that caused by FFRpap.