Takeshi Ijichi

Comparison of vascular response between durable and biodegradable polymer-based drug-eluting stents in a porcine coronary artery model.

AIMS Biodegradable polymer-based drug-eluting stents are thought to be safer than durable polymer-based stents. However, the long-term vascular response remains unclear. The aim of this study was to compare the biocompatibility of durable polymer-based sirolimus-eluting (SES) and everolimus-eluting (EES) stents with biodegradable polymer-based biolimus-eluting (BES) stents in a porcine coronary model. Stents were implanted in porcine coronaries. Acetylcholine challenge tests and optical coherence tomography (OCT) examination were performed at one month. Animals were sacrificed at three and six months (n=6 each), and the stents were analysed histologically. At one month, acetylcholine challenge tests revealed a trend towards greatest vasoconstriction in SES, less in BES, and least in EES, but the differences were not significant. OCT analysis demonstrated the highest incidence of uncovered struts in SES, followed by BES, while EES showed almost complete strut coverage (41.7±27.0%, 24.5±23.8%, 0.4±0.8%, respectively; p=0.004). Upon histological analysis at three months, SES showed a significantly higher inflammatory score than BES and EES (2.9±1.4, 0.8±0.9, 0.5±0.4, respectively; p=0.001), and this was maintained at six months (1.6±1.5, 0.3±0.3, 0.4±0.6, respectively; p=0.049). While SES showed an increased inflammatory reaction, EES and BES showed minimal inflammation. These results indicate that the late inflammatory reaction does not necessarily depend on degradability of the polymer, if the combination of the drug, metal, and polymer is biocompatible.

Coronary Angiographic Characteristics That Influence Fractional Flow Reserve

BACKGROUND Percutaneous coronary intervention (PCI) guided with fractional flow reserve (FFR) has been shown to improve clinical outcome. Although coronary angiography is the standard method for PCI guidance, the visual severity of stenosis is not always correlated with functional severity, suggesting that there are additional angiographic factors that affect functional ischemia. METHODS AND RESULTS To evaluate angiographic predictors of positive FFR in stenotic lesions, angiographic characteristics of 260 consecutive patients (362 lesions) who underwent FFR testing from April 2009 to September 2012 were analyzed. A scoring system (STABLED score) using these predictors was developed and compared with quantitative coronary angiography (QCA). %Diameter stenosis >50% (OR, 8.43; P<0.0001), tandem lesion (OR, 4.00; P<0.0001), true bifurcation (OR, 2.42; P=0.028), lesion length >20 mm (OR, 5.40; P=0.0002), and distance from ostium <20 mm (OR, 1.94; P=0.028) were determined as independent predictors of positive FFR. Area under the ROC curve for probability of positive FFR using the STABLED score (Stenosis 2 points, TAndem lesion 1 point, Bifurcation 1 point, LEsion length 1 point, Distance from ostium 1 point) was 0.85, higher than that for QCA stenosis alone (0.76). STABLED score ≥3 had 72.3% sensitivity and 83.6% specificity for predicting positive FFR, and PPV was 76.7%. CONCLUSIONS Specific angiographic features are applicable for predicting functional ischemia. STABLED score correlates well with FFR.

Transradial intervention for patients with ST elevation myocardial infarction with or without cardiogenic shock

To compare clinical outcomes between transradial (TRI) and transfemoral intervention (TFI) in primary percutaneous coronary intervention (PCI) in patients with ST elevation myocardial infarction (STEMI) with or without shock.

Tissue characterization with depth-resolved attenuation coefficient and backscatter term in intravascular optical coherence tomography images

Abstract. An important application of intravascular optical coherence tomography (IVOCT) for atherosclerotic tissue analysis is using it to estimate attenuation and backscatter coefficients. This work aims at exploring the potential of the attenuation coefficient, a proposed backscatter term, and image intensities in distinguishing different atherosclerotic tissue types with a robust implementation of depth-resolved (DR) approach. Therefore, the DR model is introduced to estimate the attenuation coefficient and further extended to estimate the backscatter-related term in IVOCT images, such that values can be estimated per pixel without predefining any delineation for the estimation. In order to exclude noisy regions with a weak signal, an automated algorithm is implemented to determine the cut-off border in IVOCT images. The attenuation coefficient, backscatter term, and the image intensity are further analyzed in regions of interest, which have been delineated referring to their pathology counterparts. Local statistical values were reported and their distributions were further compared with a two-sample t-test to evaluate the potential for distinguishing six types of tissues. Results show that the IVOCT intensity, DR attenuation coefficient, and backscatter term extracted with the reported implementation are complementary to each other on characterizing six tissue types: mixed, calcification, fibrous, lipid-rich, macrophages, and necrotic core.

Evaluation of coronary arterial calcification – Ex-vivo assessment by optical frequency domain imaging

AIMS The purpose of this study was to determine the diagnostic ability of optical frequency domain imaging (OFDI) to carry out quantitative and qualitative evaluation of coronary calcification in comparing with ex vivo human autopsy heart specimens. METHODS Analysis was carried out in 25 coronary artery specimen obtained from 16 cadavers that were imaged ex-vivo imaging by OFDI and intravascular ultrasound (IVUS). Of 235 cross-sections obtained for histologic evaluation, 149 were classified as showing calcified plaques, and in this group a comparison between histology versus co-registered images by OFDI and IVUS was performed. RESULTS Maximum thickness of calcification measured by OFDI was well correlated with histology (rs = 0.70, p < 0.0001) whereas IVUS was not useful for quantitative analysis because of the presence of acoustic shadows occurring behind calcifications. Furthermore qualitative evaluation could be carried out using OFDI, for calcifications with vague or invisible outer borders by OFDI had lipid contents (lipid pool or histologic necrotic core) more frequently as compared to those with a clear outer border (79% vs. 24%, p < 0.0001). We also found that calcified nodules, a well-recognized thrombogenic substrate, demonstrated atypical appearance in OFDI, showing irregular surfaces with high attenuation. CONCLUSION OFDI demonstrated a greater ability than IVUS to provide quantitative and qualitative evaluation of coronary arterial calcification. Precise recognition of calcified plaque morphology by OFDI may serve to determine the treatment strategy of patients having atherosclerotic coronary disease.

Transcatheter closure of atrial septal defect protects from pulmonary edema: septal occluder device gradually reduces LR shunt.

A 56-year-old woman was diagnosed as atrial septal defect (ASD) with pulmonary hypertension; pulmonary blood flow/systemic blood flow (Qp/Qs) of 2.3, pulmonary artery pressure (PAP) of 71/23(39) mmHg and diastolic dysfunction of left ventricle. PAP was improved after medical therapy; therefore, transcatheter ASD closure was performed. Seven days later, left-sided heart failure occurred, however, the improvement of Qp/Qs (1.7) and PAP of 51/21(32) was confirmed. Diuretic therapy was introduced which led to further decrease of PAP 40/12(25) and Qp/Qs (1.1). Because of gradual decrease of Qp/Qs, this patient appeared to be protected from acute pulmonary edema.

COMPARISON OF IN VIVO LONGITUDINAL STRENGTH AND CONFORMABILITY FOLLOWING STENT IMPLANTATION IN RABBIT ILIAC ARTERY

OBJECTIVES The aim of this study was to determine the in vivo longitudinal strength and conformability of various stent platforms following stent implantation in rabbit iliac arteries. BACKGROUND Recently, longitudinal coronary stent deformation has been highlighted and bench tests have demonstrated differences in longitudinal strength among various stent platforms. However, this has not been investigated in an in vivo setting. This is of interest because there may be a trade-off between longitudinal strength and conformability. METHODS We evaluated 4 types of commercially available stents: Multi-Link 8 (Abbott Vascular); Omega (Boston Scientific); Integrity (Medtronic); and Nobori (Terumo Corporation). To investigate the longitudinal strength, constant axial force was applied to the stent edge by a guiding catheter after deployment in a rabbit iliac artery. The amount of longitudinal stent deformation was calculated by measuring stent length. In order to evaluate conformability, stents were deployed crossing over the iliac bifurcation and the bifurcation angles were measured before and after stent implantation. If the change in the angle was small, the stent was considered to be more conformable. RESULTS The Omega stent demonstrated significantly greater longitudinal compression compared with other stents (Omega, 17.4 ± 9.3%; Multi-Link 8, 2.8 ± 2.3%; Integrity, 2.8 ± 1.4%; Nobori, 3.8 ± 3.2%; P=.01), but Omega showed better conformability, as evidenced by the smallest percent change in the bifurcation angle (Omega, 12.7 ± 0.8%; Multi-Link 8, 25.7 ± 2.4%; Integrity, 28.3 ± 1.1%; Nobori, 28.1 ± 6.8%; P=.03). CONCLUSION In this rabbit model, the Omega stent, which has the platform of the Element stent, showed less longitudinal strength but greater conformability compared with the other stent platforms.

Transradial coronary angiography with virtual 1 French, sheathless 3 French catheter

Minimizing catheter size can reduce bleeding complications in coronary angiography. We herein report extreme slender “needle size” (19‐G) coronary diagnostic catheterization using a new 3‐Fr diagnostic catheter by sheathless method. A 58‐year‐old man having effort angina underwent coronary angiography. The 3‐Fr Ikari Left diagnostic catheter, which is equal to 19‐G, was inserted smoothly both for left and right coronary arteries by sheathless method. We only needed 4 min to achieve hemostasis with manual compression after catheter withdrawal in this case.