Yutaka Goryo

Thin-cap fibroatheroma and large calcification at the proximal stent edge correlate with a high proportion of uncovered stent struts in the chronic phase.

ObjectiveA high proportion of uncovered stent struts is associated with late stent thrombosis after drug-eluting stent (DES) implantation, which frequently results in myocardial infarction or death. However, the predictors of uncovered stent struts remain unknown. Here, using optical coherence tomography (OCT), we studied the baseline tissue characteristics of the target coronary segment and evaluated their influence on the neointimal coverage of the strut in the chronic phase. MethodsWe analyzed 118 coronary lesions treated with OCT-guided DES implantation. OCT examinations of target lesions were performed before and after DES implantation, and tissue characteristics were evaluated within 5 mm outer segment of both stent edges. At follow-up, stent strut coverage was assessed within 5 mm inner segment from each stent edge. On the basis of the proportion of uncovered stent struts in the chronic phase, target segments were divided into poorly covered (the highest quartile with % uncovered struts, n=29) and well-covered (the remaining lower quartiles with % uncovered struts, n=89) groups. ResultsClinical parameters were similar between the two groups. On baseline OCT images, thin-cap fibroatheroma (TCFA) and large calcification were more frequently observed in the poorly covered group than the well-covered group (10.3 vs. 0.0%, P=0.0032, and 27.6 vs. 9.0%, P=0.017, respectively). Furthermore, multivariable analysis showed TCFA and large calcification at the proximal edge, but not at the distal edge, were predictors of uncover stent struts. ConclusionTCFA and large calcification at the proximal stent edge are strong predictors of uncovered stent struts. OCT is useful for selecting stent landing sites in terms of future occurrence of uncovered stent struts.

Impact of branching angle on neointimal coverage of drug-eluting stents implanted in bifurcation lesions.

ObjectivesTo investigate the impact of branching angle (BA) on neointimal coverage of drug-eluting stents (DESs) in bifurcation lesions. BackgroundPrevious experimental studies indicated that BA influences the local flow turbulence and wall shear stress, which are associated with neointimal coverage of DESs. MethodsFifty-five bifurcation lesions in 47 patients were evaluated by serial optical coherence tomography (OCT) before DES implantation and at follow-up. Neointimal coverage was assessed in cross-sectional OCT images containing the side branch; regions including the side branch ostium (SO) and vessel wall (VW) were assessed separately. BA was measured using angiography (Angio-BA) and longitudinal OCT imaging (OCT-BA). ResultsIn the SO region, a significant negative correlation was found between the uncovered strut percentage and Angio-BA or OCT-BA (r=−0.41, P=0.0024; r=−0.33, P=0.0167, respectively) and a significant positive correlation was found between Angio-BA and average neointimal thickness (r=0.31, P=0.025), whereas no correlation was observed between OCT-BA and average neointimal thickness (r=0.20, P=0.158). In the VW region, no correlation was found between Angio-BA or OCT-BA and the uncovered strut percentage or average neointimal thickness. ConclusionBA influence the neointimal coverage over DES struts in the SO at coronary bifurcation lesions, but not in those attached to the VW.

Changes in the reference lumen size of target lesions before and after coronary stent implantation: Evaluation with frequency domain optical coherence tomography☆☆☆

Objective In optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI), stent size is usually determined according to the pre-PCI lumen size of either the distal or proximal reference site. However, the effect of the OCT imaging catheter crossing the target lesion on the reference lumen measurements has not been studied. We evaluated changes in the reference lumen size before and after PCI using frequency domain OCT. Methods For 100 consecutive patients with PCI, mean lumen diameter (LD) and lumen area (LA) were measured at the proximal and distal reference sites before and after coronary stent implantation with OCT. Results Mean LD and LA of the distal reference site were significantly increased after PCI with stent implantation (2.57 ± 0.6 to 2.62 ± 0.64 mm, p < 0.01 and 5.20 ± 2.66 to 5.41 ± 2.54 mm2, p < 0.01, respectively). By contrast, these indices at the proximal reference site were significantly decreased. ROC curve analysis selected MLA of 1.50 mm2 as the best cutoff value for changes in mean LD. Distal mean LD was markedly increased after PCI in lesions with MLA < 1.50 mm (2.28 ± 0.48 to 2.40 ± 0.17 mm, P < 0.001), but did not change in lesions with MLA > 1.50 mm2. Tissue characteristics were not correlated with changes in reference lumen size. Conclusions When we select the stent size during OCT-guided PCI, we need to pay attention to the decrease in the luminal measurement of the reference sites, especially in lesions with tight stenosis.

Pacemaker System Malfunction Resulting from External Electrical Cardioversion: A Case Report

In May 2005 a 68‐year‐old woman received a VDD pacemaker implantation in the right pectoral region at our hospital for the treatment of complete atrioventricular block. In July 2008, she was diagnosed with dilated cardiomyopathy based on histological testing. In November 2008, she developed syncope due to ventricular tachycardia while at another hospital. She underwent external electrical cardioversion with an anterior‐lateral paddle position using a single shock of 100 J. This shock led to severe bradycardia resulting in a transfer to our hospital. The physician who provided the shock could not have been aware that the patient had an implanted pacemaker. The skin above the pulse generator was burned. The electrocardiogram showed no pacing spikes or ventricular escape rhythm. Investigation of the pacemaker 3 hours after cardioversion revealed reprogramming of the device and a marked rise in the lead impedance (>3,000 ohm). Removal of the generator and implantation of a biventricular cardioverter defibrillator were required. The emergency situation, the small size of the generator, the small incision made using the buried suture method, and the patients obesity all probably contributed to the physicians not noticing the implanted pacemaker. It is important to increase awareness of the severe consequences that may follow if the physician administering external defibrillation does not know about the patients implanted pacemaker.

Coronary bifurcation bench test using multimodality imaging: Impact of stent strut link location on stent deformity and jailed side-branch orifices during re-proximal optimizing technique

The purpose of this study was to compare the stent deformation, obstruction of stent struts at a jailed side branch (SB) ostium, and stent strut malapposition after a repetitive proximal optimizing technique (re‐POT) sequence between bifurcation lesions with and without stent links at SB ostia in ex vivo experimental setting.

Vascular Healing Response after Everolimus-Eluting Stent Implantation in Acute Coronary Syndrome Culprit Lesions: Comparison with Implantation in Stable Angina Pectoris

Background To evaluate the neointimal conditions of everolimus-eluting stents (EESs) implanted in culprit lesions of patients with acute coronary syndrome (ACS) compared with stable angina pectoris (SAP) using optical coherence tomography (OCT). EESs are second-generation drug-eluting stents that have recently been shown to be useful in patients with ACS as well as in patients with SAP. However, few studies have analyzed the intra-stent conditions of EESs that can lead to favorable results in such ACS lesions. Methods We evaluated 41 ACS patients with EES implantation (age, 66.7 ± 10.3 years) and 59 SAP patients enrolled as controls (age, 68.3 ± 10.7 years). OCT examinations were performed after 9 months of follow-up after stent implantation, and the condition of the neointimal coverage over every stent strut was assessed in 1-mm intervals. In addition, neointimal thickness (NIT) over each strut was measured and tissue characteristics were examined. Results There was no significant difference in mean NIT between the ACS (90.8 ± 88.2 mm) and SAP (87.3 ± 74.2 mm, p = 0.11) group. The rate of uncovered struts was significantly lower in the ACS group (11.5%) than in the SAP group (12.5%, p = 0.03). Neointimal tissue characteristics were also similar between groups. Conclusions Vascular responses after EES implantation differed significantly between ACS and SAP lesions using OCT. However, these differences were considered small in clinical terms. Our OCT data support the favorable results of patients with EES implantation at mid-term follow-up, even in those with ACS.

CHANGES IN THE FIBROUS CAP THICKNESS COVERING LIPID POOL AFTER DRUG ELUTING STENT IMPLANTATION - OCT STUDY

The thin fibrous cap covering large lipid pool is known as one of the risks for coronary plaque rupture and subsequent acute coronary events. However, little is known about the influence of drug eluting stent (DES) implantation on the tissue characteristics of coronary plaque with lipid accumulation

VASCULAR HEALING RESPONSE OF CALCIFIED CORONARY LESIONS AFTER EVEROLIMUS ELUTING STENT IMPLANTATION: EVALUATION WITH OPTICAL COHERENCE TOMOGRAPHY

Percutaneous coronary intervention (PCI) with drug eluting stent (DES) has substantially decreased the rate of in-stent restenosis, and improved prognosis of patients with coronary artery disease. However, presence of coronary artery calcification (CAC) increases the rate of long-term adverse events