Naohiro Komura

Impact of Ultrasound Attenuation and Plaque Rupture as Detected by Intravascular Ultrasound on the Incidence of No-Reflow Phenomenon After Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction

OBJECTIVES The aim of this study was to assess whether ultrasound attenuation and plaque rupture as detected by intravascular ultrasound (IVUS) are associated with the incidence of no-reflow phenomenon after percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). BACKGROUND No-reflow phenomenon is associated with worse long-term outcomes after STEMI. Therefore, reliable and feasible intravascular imaging techniques are needed to identify patient subgroups that would be at high risk for no-reflow phenomenon. METHODS One hundred seventy consecutive patients with STEMI who underwent PCI within 12 h after symptom onset were enrolled. The IVUS interrogation was performed before PCI. RESULTS No-reflow phenomenon occurred in 30 patients (18%), who had a higher incidence of no ST-segment resolution (50% vs. 9%; p < 0.001), a higher peak creatine kinase level (4,090 IU/l vs. 2,823 IU/l; p < 0.001), and a lower left ventricular ejection fraction in the chronic phase (51% vs. 59%; p < 0.01). Multivariate logistic regression analysis revealed that ultrasound attenuation with a longitudinal length of > or =5 mm, plaque rupture, and reperfusion time correlated with no-reflow phenomenon (all p < 0.05). In patients with both ultrasound attenuation > or =5 mm and plaque rupture, the incidence of no-reflow phenomenon was 88%, and the risk of decreased coronary reflow was higher than that predicted by either factor alone (p = 0.004 for interaction). CONCLUSIONS In patients with STEMI, a longer ultrasound attenuation and plaque rupture on IVUS are associated with an increased incidence of no-reflow phenomenon, suggesting that this subset of patients might be at high risk for distal embolism.

Relation between hyperinsulinemia and nonculprit plaque characteristics in nondiabetic patients with acute coronary syndromes.

OBJECTIVES We sought to assess whether hyperinsulinemia is associated with percentage lipid and coronary plaque burden in nondiabetic patients with acute coronary syndromes (ACS). BACKGROUND Hyperinsulinemia carries an increased risk of cardiovascular disease even in pre-diabetic patients, but the precise mechanisms of its effects remain unclear. METHODS Nonculprit coronary lesions associated with mild-to-moderate stenosis in 82 nondiabetic patients with ACS were examined by integrated backscatter intravascular ultrasound (IB-IVUS), using a 40-MHz intravascular catheter. Conventional IVUS and IB-IVUS measurements from the worst 10-mm segment (1-mm intervals) were calculated. All patients underwent a 75-g oral glucose tolerance test (OGTT) to calculate the area under the insulin concentration-time curve (AUC insulin) from 0 to 120 min. RESULTS Patients in the high tertile of AUC insulin had a significantly greater percentage lipid area and absolute lipid volume than did patients in the intermediate and low tertiles (tertile 3 vs. tertile 2 vs. tertile 1; 37.6 ± 16.6% vs. 25.8 ± 11.9% vs. 27.5 ± 14.7%, p < 0.01 by analysis of variance [ANOVA], and 29.9 ± 22.6 mm(3) vs. 15.3 ± 12.6 mm(3) vs. 17.7 ± 12.7 mm(3), p < 0.01 by ANOVA, respectively) and a smaller percentage fibrosis area (55.0 ± 11.5% vs. 61.7 ± 9.4% vs. 60.7 ± 9.4%, p = 0.03 by ANOVA). Multiple regression analysis showed that the high tertile of AUC insulin was independently associated with an increased percentage lipid area (p < 0.05). On conventional IVUS analysis, external elastic membrane cross-sectional area was significantly increased with greater plaque volume in patients in the high tertile of AUC insulin (both p < 0.05 by ANOVA). CONCLUSIONS Hyperinsulinemia is associated with an increased lipid content and a greater plaque volume of nonculprit intermediate lesions in nondiabetic patients with ACS, suggesting that plaque vulnerability is increased in this subgroup of patients.

Intravascular ultrasound morphology of culprit lesions and clinical demographics in patients with acute coronary syndrome in relation to low-density lipoprotein cholesterol levels at onset

Despite current standards of care aimed at achieving targets for low-density lipoprotein cholesterol (LDL-C), many patients remain at high residual risk of cardiovascular events. We sought to assess the LDL-C-dependent differences in culprit intravascular ultrasound (IVUS) morphologies and clinical characteristics in patients with acute coronary syndrome (ACS). Eighty-six consecutive ACS patients whose culprit lesions imaged by preintervention IVUS were divided into two groups based on the fasting LDL-C level on admission: a low-LDL-C group (LDL-C <2.6 mmol/l, n = 45) and a high-LDL-C group (LDL-C ≥2.6 mmol/l, n = 41). Patients with stable angina with LDL-C <2.6 mmol/l (n = 30) were also enrolled as an age- and gender-matched control. The low-LDL-C ACS group was significantly older (72 ± 12 vs 64 ± 14 years, P = 0.007) and more diabetic (47 % vs 15 %, P = 0.001). Importantly, IVUS morphologies were comparable between low- and high-LDL-C ACS groups (all P not significant), whereas culprit plaque was more hypoechoic and less calcified in the low-LDL-C ACS group than in the low-LDL-C stable angina group. Furthermore, compared with the low-LDL-C ACS nondiabetic group, the low-LDL-C ACS diabetic group was more obese, more triglyceride rich (1.3 ± 0.6 vs 0.9 ± 0.4 mmol/l, P = 0.003), and more endothelially injured, but no different for the culprit IVUS morphologies. In multivariate analysis, diabetes was independently associated with a low LDL-C level on admission in patients with ACS. There was no relationship between the LDL-C level at onset and culprit-plaque IVUS morphologies in ACS patients, although culprit plaque in the low-LDL-C ACS group was more vulnerable than in the low-LDL-C stable angina group. In patients with low-LDL-C levels, diabetes with atherogenic dyslipidemia might be the key residual risk.

Plaque REgression with Cholesterol absorption Inhibitor or Synthesis inhibitor Evaluated by IntraVascular UltraSound (PRECISE-IVUS Trial): Study protocol for a randomized controlled trial

BACKGROUND Although the positive association between achieved low-density lipoprotein cholesterol (LDL-C) level and the risk of coronary artery disease (CAD) has been confirmed by randomized studies with statins, many patients remain at high residual risk of events suggesting the necessity of novel pharmacologic strategies. The combination of ezetimibe/statin produces greater reductions in LDL-C compared to statin monotherapy. PURPOSE The Plaque REgression with Cholesterol absorption Inhibitor or Synthesis inhibitor Evaluated by IntraVascular UltraSound (PRECISE-IVUS) trial was aimed at evaluating the effects of ezetimibe addition to atorvastatin, compared with atorvastatin monotherapy, on coronary plaque regression and change in lipid profile in patients with CAD. METHODS The study is a prospective, randomized, controlled, multicenter study. The eligible patients undergoing IVUS-guided percutaneous coronary intervention will be randomly assigned to receive either atorvastatin alone or atorvastatin plus ezetimibe (10 mg) daily using a web-based randomization software. The dosage of atorvastatin will be increased by titration within the usual dose range with a treatment goal of lowering LDL-C below 70 mg/dL based on consecutive measures of LDL-C at follow-up visits. IVUS will be performed at baseline and 9-12 months follow-up time point at participating cardiovascular centers. The primary endpoint will be the nominal change in percent coronary atheroma volume measured by volumetric IVUS analysis. CONCLUSION PRECISE-IVUS will assess whether the efficacy of combination of ezetimibe/atorvastatin is noninferior to atorvastatin monotherapy for coronary plaque reduction, and will translate into increased clinical benefit of dual lipid-lowering strategy in a Japanese population.

Effects of 4 Statins on Regression of Coronary Plaque in Acute Coronary Syndrome.

BACKGROUND There is no information on differences in the effects of moderate- and low-intensity statins on coronary plaque in patients with acute coronary syndrome (ACS). The aim of this study was to compare the effects of 4 different statins in patients with ACS, using intravascular ultrasound (IVUS). METHODSANDRESULTS A total of 118 patients with ACS who underwent IVUS before percutaneous coronary intervention and who were found to have mild to moderate non-culprit coronary plaques were randomly assigned to receive either 20 mg/day atorvastatin or 4 mg/day pitavastatin (moderate-intensity statin therapy), or 10 mg/day pravastatin or 30 mg/day fluvastatin (low-intensity statin therapy). IVUS at baseline and at end of 10-month treatment was available in 102 patients. Mean percentage change in plaque volume (PV) was -11.1±12.8%, -8.1±16.9%, 0.4±16.0%, and 3.1±20.0% in the atorvastatin, pitavastatin, pravastatin, and fluvastatin groups, respectively (P=0.007, ANOVA). Moderate-intensity statin therapy induced regression of PV, whereas low-intensity statin therapy produced insignificant progression (-9.6% vs. 1.8%, P<0.001). On multivariate linear regression analysis, moderate-intensity statin therapy (P=0.02) and uric acid at baseline (P=0.02) were significant determinants of large percent PV reduction. LDL-C at follow-up did not correlate with percent PV change. CONCLUSIONS Moderate-intensity statin therapy induced regression of coronary PV, whereas low-intensity statin therapy resulted in slight progression of coronary PV in patients with ACS. (Circ J 2016; 80: 1634-1643).

Impact of left ventricular hypertrophy on impaired coronary microvascular dysfunction

Impact of left ventricular hypertrophy on impaired coronary microvascular dysfunction Kenichi Tsujita ⁎, Kenshi Yamanaga , Naohiro Komura , Kenji Sakamoto , Takashi Miyazaki , Masanobu Ishii , Noriaki Tabata , Tomonori Akasaka , Daisuke Sueta , Yuichiro Arima , Sunao Kojima , Eiichiro Yamamoto , Megumi Yamamuro , Tomoko Tanaka , Yasuhiro Izumiya , Shinji Tayama , Sunao Nakamura , Koichi Kaikita , Seiji Hokimoto , Hisao Ogawa a

Percutaneous coronary intervention strategy for acute coronary syndrome caused by spontaneous coronary artery dissection for relieving ongoing ischemia—Case series and literature review

Although spontaneous coronary artery dissection (SCAD) is one of the causes of acute coronary syndrome (ACS) or sudden cardiac death, its standard management, especially primary percutaneous coronary intervention (PCI) in ACS patients with ongoing ischemia, has not been established. We experienced three ACS patients with SCAD who were treated with a different strategy of primary PCI. Each PCI strategy led to different clinical and procedural results. We describe here such PCI strategies and results, and also discuss the literature regarding primary PCI strategies for SCAD-induced ACS patients with ongoing ischemia. <Learning objective: SCAD is a cause of ACS. However, the treatment strategy of primary PCI for SCAD has not been fully investigated. We used different PCI strategies for three SCAD patients with ongoing ischemia. Our case series suggested that plain old balloon angioplasty is an acceptable option to avoid coronary stenting because the majority of patients were young menstruating women. Coronary vasospasm might be associated with SCAD. Treatment with vasodilators could be a potential pharmacological option for avoiding recurrence of SCAD.>.

Impaired Peripheral Endothelial Function Assessed by Digital Reactive Hyperemia Peripheral Arterial Tonometry and Risk of In‐Stent Restenosis

Background Drug‐eluting stents are replacing bare‐metal stents, but in‐stent restenosis (ISR) remains a problem. Reactive hyperemia index (RHI) assessed by peripheral arterial tonometry evaluates endothelial function noninvasively. We prospectively assessed the prognostic value of RHI in predicting ISR after percutaneous coronary intervention. Methods and Results RHI was measured before percutaneous coronary intervention and at follow‐up (F/U) angiography (F/U RHI; 6 and 9 months post bare‐metal stents– and drug‐eluting stents– percutaneous coronary intervention, respectively) in 249 consecutive patients. At F/U, ISR (stenosis >50% of diameter) was seen in 68 patients (27.3%). F/U natural logarithm (RHI) was significantly lower in patients with ISR than in those without (0.52±0.23 versus 0.65±0.27, P<0.01); no between‐group difference in initial natural logarithm (RHI) (0.60±0.26 versus 0.62±0.25, P=0.56) was seen. By multivariate logistic regression analysis, even after adjusting for other significant parameters in univariate analysis, F/U natural logarithm (RHI) independently predicted ISR (odds ratio: 0.13; 95% CI: 0.04–0.48; P=0.002). In receiver operating‐characteristic analysis, F/U RHI was the strongest predictor of ISR (area under the curve: 0.67; 95% CI: 0.60–0.75; P<0.01; RHI <1.73 had 67.6% sensitivity, 64.1% specificity); area under the curve significantly improved from 0.62 to 0.70 when RHI was added to traditional ISR risk factors (P=0.02). Net reclassification index was significant after addition of RHI (26.5%, P=0.002). Conclusions Impaired RHI at F/U angiography independently correlated with ISR, adding incremental prognostic value to the ISR‐risk stratification following percutaneous coronary intervention. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02131935.

Synergistic effect of ezetimibe addition on coronary atheroma regression in patients with prior statin therapy: Subanalysis of PRECISE-IVUS trial.

Background The IMPROVE-IT trial showed that the clinical benefit of statin/ezetimibe combination appeared to be pronounced in patients with prior statin therapy. We hypothesized that the antiatherosclerotic effect of atorvastatin/ezetimibe combination was pronounced in patients with statin pretreatment. Methods In the prospective, randomized, controlled, multicenter PRECISE-IVUS trial, 246 patients undergoing intravascular ultrasound-guided percutaneous coronary intervention were randomized to atorvastatin/ezetimibe combination or atorvastatin alone. The dosage of atorvastatin was uptitrated with a treatment goal of lowering low-density lipoprotein cholesterol to below 70 mg/dl in both groups. Serial volumetric intravascular ultrasound was performed at baseline and 9–12 month follow-up to quantify the coronary plaque response in 202 patients. We compared the intravascular ultrasound endpoints in all subjects, stratified by the presence or absence of statin pretreatment. Results The baseline low-density lipoprotein cholesterol level (100.7 ± 23.1 mg/dl vs. 116.4 ± 25.9 mg/dl, p < 0.001) and lathosterol (55 (38 to 87)) µg/100 mg total cholesterol vs. 97 (57 to 149) µg/100 mg total cholesterol, p < 0.001) was significantly lower, and campesterol/lathosterol ratio (3.9 (2.4 to 7.4) vs. 2.6 (1.5 to 4.1), p < 0.001) was significantly increased in patients with statin pretreatment. Contrary to the patients without statin pretreatment (−1.3 (−3.1 to −0.1)% vs. −0.9 (−2.3 to 0.9)%, p = 0.12), the atorvastatin/ezetimibe combination showed a significantly stronger reduction in delta percent atheroma volume, compared with atorvastatin alone, in patients with statin pretreatment (−1.8 (−3.6 to −0.3)% vs. −0.1 (−1.6 to 0.8)%, p = 0.002). Conclusion Compensatory increase in cholesterol absorption observed in statin-treated patients might attenuate the inhibitory effects of statins on coronary plaque progression. A low-dose statin/ezetimibe combination might be a promising option in statin-hyporesponder.

Serial intravascular ultrasound assessment of very late stent thrombosis after sirolimus-eluting stent placement

PURPOSE In-stent restenosis has been decreasing through the introduction of drug-eluting stents (DES). On the other hand, adverse events such as very late stent thrombosis (VLST) and late catch-up phenomenon can occur especially with sirolimus-eluting stents (SES, first-generation DES) in long-term follow-up. However, the precise mechanisms underlying VLST have not been well investigated in vivo. METHODS AND RESULTS From 2004 to 2010, 2034 SES were implanted in 1656 patients and caused eight VLST (0.48% per patient) at Fukuoka Tokushukai Medical Center. Of these, serial intravascular ultrasound (IVUS) images (post-stent implantation and at the time of VLST onset) were obtained from three patients with VLST. Comparing them with eight control patients with SES implanted, the vascular reactivity of VLST patients was analyzed. Eight VLST happened 50 ± 15 months after stent implantation and three of the eight patients with VLST had not taken aspirin daily. There were no differences in minimum stent area, maximum external elastic membrane (EEM) area, and stent edge (distal and proximal) EEM area in post-procedural IVUS images. Compared with the control group patients, ΔEEM area (10.6 ± 3.4mm(2) vs. 1.7 ± 1.9 mm(2), p=0.01) and vessel expansion ratio (185.6 ± 40.3% vs. 112.0 ± 12.1%, p=0.01) were significantly greater in the VLST group based on the greater peri-stent plaque expansion (262.1 ± 72.8% vs. 118.7 ± 21.2%, p=0.01). CONCLUSION Our serial IVUS study showed that the vascular positive remodeling after SES implantation is one of the most probable morphological mechanisms for VLST development.