Short- and mid-term influence of drug-coated stent implantation on structural and functional vascular healing response: An optical coherence tomography and acetylcholine testing study.

OBJECTIVE: This study investigated the effect of a drug-coated stent (DCS) that has a novel microporous abluminal surface without a polymer on 1-month and 1-year functional and morphological healing response as assessed using acetylcholine (Ach) testing and optical coherence tomography (OCT). BACKGROUND: DCS is expected to induce favorable morphological and physiological arterial healing after its implantation. METHODS: A total of 11 patients who underwent vascular response examinations 1-month and 1-year after the index PCI with DCS implantation were enrolled. The vascular response was evaluated by the functional response test by acetylcholine infusion, the morphological response test by OCT. RESULTS: Although 94.5% of the DCS struts were covered by homogeneous smooth neointima at 1 month, the percentage of neointimal coverage increased to 98.5% at 1 year (p = .02). Conversely, the proportion of uncovered struts and malapposed struts at 1 year were 1.2 and 0.7%, respectively. Furthermore, the coronary vasomotor response to incremental doses of Ach were impaired especially in the distal segments at each period, although the responses to Ach at 10-6 mol/L in the distal segment tended to improve over time from baseline to 1 month and 1 year later (-19 ± 20%, -9 ± 17%, and -5 ± 14%, respectively; p = .27). CONCLUSIONS: The morphological assessment of DCS with OCT revealed a high degree of strut coverage and apposition at 4 weeks after implantation. The impaired endothelium-dependent vasomotor response tended to improve chronologically from baseline to 1 month and 1 year later.

Distribution of pressure gradients along the left anterior descending artery in patients with angiographically normal arteries.

OBJECTIVES: This study tested the hypothesis that there is no decline of coronary pressure from the proximal to the distal left anterior descending coronary artery (LAD) of humans and swine. BACKGROUND: In the daily clinical practice, the fractional flow reserve (FFR) in the LAD is frequently lower than that in the other arteries in the presence of a similar degree of stenosis. METHODS: Twenty-six patients with angiographically normal LAD were prospectively enrolled. The coronary pressure ratio (mean distal/proximal coronary pressures at hyperemia) was measured at five different positions: 12, 10, 7, and 5 cm distal from the LAD ostium, and at the ostium of the LAD. The coronary pressure measurement was further investigated in a swine model without atherosclerosis. RESULTS: The coronary pressure ratio during maximum hyperemia gradually decreased in proportion to the distance from the ostium (average: 0.85 ± 0.06 at 12 cm distal to the ostium). This finding was confirmed in swine model. The degree of the coronary pressure decrease during maximum hyperemia was similar in patients with and without evidence of minor plaque on intravascular ultrasound, however it was strongly associated with the amount of myocardium mass in the territory of the LAD. CONCLUSIONS: Intracoronary pressure gradually decreases in proportion to the distance from the ostium in the LAD of humans and swine, regardless of the presence of minor atherosclerotic plaques. The degradation degree of the coronary pressure ratio during maximum hyperemia is enlarged in the presence of larger amount of myocardium mass in the territory of the LAD.

Impact of optical coherence tomography-derived neointimal tissue morphology on development of very late in-stent restenosis.

OBJECTIVES: This study evaluated the progression of very late in-stent restenosis (VL-ISR) by analyzing four serial coronary angiography (CAG) images and its correlation with neointimal tissue characterization of the VL-ISR lesions on optical coherence tomography (OCT). BACKGROUND: Recently, VL-ISR is occasionally observed beyond a few years after drug-eluting stents (DESs) implantation. METHODS: This study analyzed 50 VL-ISR lesions after DES in which 4 serial CAGs over a period of 2 years, including at baseline procedure, 9 months after baseline procedure, 12 months before VL-ISR, and at the time of VL-ISR, were performed. Neointimal tissue characteristics by OCT were categorized as homogeneous, heterogeneous with invisible strut (Type I), heterogeneous with visible strut (Type II), speckled (Type III), or heterogeneous with sharply delineated border (Type IV). RESULTS: From the development process, 23 VL-ISRs (46%) were categorized as rapid progression and 27 (54%) as gradual progression. The five categories of neointimal tissue composition significantly differed between lesions with rapid and gradual progression. Homogeneous neointima and Type IV heterogeneous neointima were observed only in lesions with gradual progression. Moreover, most Type I heterogeneous neointima was identified in lesions with gradual progression. Instead, main neointimal tissue components of lesions with rapid progression were Type II (43%) and Type III (43%) heterogeneous neointima. CONCLUSION: The progression rate of in-stent atherosclerotic changes is gradual, whereas organized thrombus could be associated with an increased risk of rapid neointimal growth. The two types of stenosis progression provide a new insight into the mechanism of VL-ISR development after DES implantation.

Effect of neointimal tissue morphology on vascular response to balloon angioplasty in lesions with in-stent restenosis after drug-eluting stent deployment: an optical coherence tomography analysis.

This study aimed to evaluate the vascular response to balloon angioplasty for drug-eluting stent (DES) in-stent restenosis (ISR) lesions based on our novel optical coherence tomography (OCT) classification to establish the optimal treatment strategy for ISR lesions after DES implantation. A total of 104 ISR lesions after DES implantation were imaged by OCT and categorized into the following six patterns: type I-homogeneous high-intensity tissue, type II-heterogeneous tissue with signal attenuation, type III-speckled heterogeneous tissue, type IV-mixed tissue containing poorly delineated region with invisible strut, type V-mixed tissue containing sharply delineated low-intensity region, and type VI-bright protruding tissue with an irregular surface. Serial volumetric OCT analysis was performed before and after balloon dilation to evaluate the vascular response to balloon angioplasty. After balloon dilation, the minimal decrease in neointimal volume was noted in type I lesions and maximal in type III lesions. In contrast, the increase in stent volume was significantly more in type I lesions than others. Neointimal tissue characterization by OCT allows us to provide useful information about the vascular response to balloon dilation, which can influence the therapeutic strategy for DES ISR lesions.

Optical coherence tomography characteristics of in-stent restenosis after drug-eluting stent implantation: a novel classification and its clinical significance.

This study aimed to establish a novel classification of in-stent restenosis (ISR) morphological characteristics after drug-eluting stent (DES) implantation as visualized by optical coherence tomography (OCT) and determine its clinical significance. A total of 133 lesions with intrastent restenosis after DES implantation were imaged by OCT. Neointimal tissue characteristics were categorized according to the classical classification as either homogeneous, heterogeneous, or layered. Then all tissues were also classified into six types as follows: homogeneous high-intensity tissue (type I), heterogeneous tissue with signal attenuation (type II), speckled heterogeneous tissue (type III), heterogeneous tissue containing poorly delineated region with invisible strut (type IV), heterogeneous tissue containing sharply delineated low-intensity region (type V), or bright protruding tissue with an irregular surface (type VI). The kappa value for interobserver agreement between the two observers was higher in the modified classification than in the classical classification (0.97 and 0.72, respectively). Most lesions classified as type V and VI were likely to be identified in patients on hemodialysis and located at the ostial right coronary artery. The duration from stent implantation to ISR was significantly longer in types IV and VI than in others. The incidence of stent fracture was significantly higher in types I and IV. This new modified classification enabled us to classify most ISR lesions easily with higher reproducibility. The clinical significance of neointimal restenotic tissue classification by OCT became clear while using the modified classification.

Utility and Validity of Intracoronary Administration of Nicorandil Alone for the Measurement of Fractional Flow Reserve in Patients With Intermediate Coronary Stenosis.

BACKGROUND: Intracoronary (IC) administration of nicorandil has been proposed as an alternative choice of hyperemic agent for fractional flow reserve (FFR) measurements. This study evaluated the utility and validity of IC nicorandil administration alone to induce maximal hyperemia.Methods and Results:Two-hundred-seven patients with coronary artery disease listed for coronary angiography with FFR were prospectively enrolled. FFR was measured after (1) IC administration of nicorandil 2 mg (ICNIC2 mg); (2) continuous intravenous (IV) adenosine triphosphatase (ATP) infusion at 150 µg/kg/min (IVATP150); (3) IV ATP infusion at 210 µg/kg/min (IVATP210); (4) IC administration of 0.5 mg nicorandil during IVATP150 (ICNIC0.5 mg+IVATP150); (5) IC administration of 1 mg nicorandil during IVATP150 (ICNIC1 mg+IVATP150); and (6) IC administration of 2 mg nicorandil during IVATP150 (ICNIC2 mg+IVATP150). The average FFR values and the rate of achieving maximum hyperemia after ICNIC2 mg, IVATP150, IVATP210, ICNIC0.5 mg+IVATP150, ICNIC1 mg+IVATP150, and ICNIC2 mg+IVATP150 were 0.85±0.08, 0.89±0.08, 0.85±0.09, 0.84±0.08, 0.83±0.08, 0.83±0.08 (P<0.01), and 92%, 54%, 91%, 96%, 99%, 99% (P<0.01), respectively. The incidence of systolic aortic pressure drop, chest discomfort, and transient atrioventricular block increased in a dose-dependent manner after IV ATP infusion, but almost no adverse effects were observed after ICNIC2 mg. CONCLUSIONS: ICNIC2 mg produced a more pronounced hyperemia than continuous IV ATP, and might be the preferred method for assessment of FFR.

Atherosclerotic Component of the Yellow Segment After Drug-Eluting Stent Implantation on Coronary Angioscopy　- An Ex-Vivo Validation Study.

BACKGROUND: Coronary angioscopy (CAS) is used to comprehensively evaluate vascular responses after drug-eluting stent (DES) implantation. This study sought to evaluate the capability of CAS for evaluating DES strut coverage grade and color grade of the intima compared with histological images in coronary autopsy specimens. Methods and Results: A total of 23 DES extracted from 11 autopsy hearts were imaged by CAS. All stent segments were graded as white or yellow according to the luminal surface color, and thrombus was evaluated according to a previous report. Neointimal coverage over the DES was graded as 0 (stent struts fully visible) to grade 3 (stent struts fully embedded and invisible). Of 76 segments, neointimal coverage was graded as 0 in 35 (46%), 1 in 22 (29%), 2 in 8 (11%), and 3 in 11 (14%). The neointimal thickness increased significantly with increasing neointimal coverage grade on angioscopy. Neointimal color was graded as white in 40 (53%) and yellow in 36 segments (47%). Histological analysis revealed that yellow neointima contained fibroatheroma, foam cells accumulation or superficial calcium deposition. A thrombus was identified in 13 segments. Thrombi adherent around the stent strut were partly intimal erythrocyte accumulation around the strut. CONCLUSIONS: In-stent yellow segment had atherosclerotic components. CAS could evaluate vascular status comprehensively after DES implantation.

Impact of analysis interval size on the quality of optical frequency domain imaging assessments of stent implantation for lesions of the superficial femoral artery.

OBJECTIVES: This study aimed to investigate the influence of analysis interval size on optical frequency domain imaging (OFDI) assessment of stent therapy for lesions of the superficial femoral artery (SFA). BACKGROUND: No consensus or validating data are available with respect to the methodology of intravascular imaging analysis for the peripheral arteries. METHODS: OFDI was performed for 30 SFA lesions, during endovascular therapy and at the 6-month follow-up. Initially, lumen and stent borders were traced at 1-mm axial intervals. Volumes were calculated using a PC-based software, and the volume index (VI) was defined as the volume divided by the stent length. Two additional OFDI analyses were performed using 2-mm and 5-mm intervals, thereby reducing the number of cross-sectional image frames analyzed. RESULTS: The mean stent length was 89.7 ± 35.2 mm. The mean difference in baseline minimum lumen area (MLA) was 0.4 mm2 between MLA values from the 1-mm and 2-mm interval analyses, and 2.2 mm2 between MLA values from the 1-mm and 5-mm interval analyses. In volumetric analysis, there were excellent correlations and good agreements for stent, lumen, and neointimal VI measurements obtained on the basis of different analysis intervals. CONCLUSIONS: Using large intervals in OFDI analyses of SFA lesions resulted in few differences in measurement variability of volumetric parameters. However, planar analysis for MLA assessment can be susceptible to high variability when large intervals are applied. © 2016 Wiley Periodicals, Inc.

The distribution of calcified nodule and plaque rupture in patients with peripheral artery disease: an intravascular ultrasound analysis.

In addition to plaque rupture (PR), calcified nodule (CN) may also have the potential to develop into arterial thrombus in the peripheral arteries. This study evaluated the distribution of plaque ruptures and calcified nodules in the peripheral arteries and their impact on the outcome of endovascular therapy (EVT). Consecutive 159 patients who underwent EVT with intravascular ultrasound guidance were enrolled. The position of CNs and PRs were assigned to any of common iliac artery, external iliac artery, common femoral artery, and superficial femoral artery. Forty-six (29%) patients had calcified nodule and twenty-eight (18%) patients had plaque rupture somewhere in the lower limb arteries. Although calcified nodules were evenly distributed throughout the length of the arteries plaque ruptures were predominantly located in the proximal segment of the iliofemoral arteries. Stent expansion ratio was significantly smaller in the target arteries with calcified nodules than in those with plaque rupture. Multivariate logistic regression analysis identified hemodialysis as an independent clinical predictor of calcified nodule (odds ratio 8.15, 95% confidence interval 1.73-38.3; P = 0.008). CN definitely affects incomplete stent deployment in the peripheral artery contributing to adverse events, on the other hand, PR has more acceptable outcomes after stent implantation. In the clinical setting, it is important that we realize the features of peripheral artery disease and its patient characteristics which having CNs and PRs to make a strategy for revascularization.

Impact of thermodilution-derived coronary blood flow patterns after percutaneous coronary intervention on mid-term left ventricular remodeling in patients with ST elevation myocardial infarction.

We recently reported the coronary thermodilution curve can be evaluated by analyzing the thermodilution curve obtained from a pressure sensor/thermistor-tipped guidewire, and presence of a bimodal-shaped thermodilution curve following primary percutaneous coronary intervention (pPCI) in ST-segment elevation myocardial infarction (STEMI) patients was associated with worse outcomes. This study evaluated whether the bimodal-shaped thermodilution curve predicts left ventricular (LV) remodeling after STEMI. The coronary thermodilution curve patterns were evaluated for 75 patients treated by pPCI for their first STEMI using a pressure sensor/thermistor-tipped guidewire, and classified into the three groups according to the thermodilution curve shape: narrow unimodal (n = 39), wide unimodal (n = 26), and bimodal pattern (n = 10). Echocardiography was performed at baseline and 6 months after STEMI. LV remodeling was defined as a >20 % increase in LV end-diastolic volumes (LVEDV). LVEDV at 6-month follow-up was greater in the bimodal group than in the other groups (p < 0.001). The prevalence of LV remodeling was highest in the bimodal group than in the narrow and wide unimodal groups (60, 12, and 15 %, respectively; p = 0.003). Multivariate analysis revealed a bimodal-shaped thermodilution curve as an independent predictor of the prevalence of LV remodeling. A bimodal-shaped thermodilution curve is associated with LV remodeling after STEMI. This easily assessable coronary thermodilution curve pattern is useful to predict mid-term LV remodeling for STEMI patients at the catheterization laboratory.

Intravascular Ultrasound-Derived Stent Dimensions as Predictors of Angiographic Restenosis Following Nitinol Stent Implantation in the Superficial Femoral Artery.

PURPOSE: To identify intravascular ultrasound (IVUS) measurements that can predict angiographic in-stent restenosis (ISR) following nitinol stent implantation in superficial femoral artery (SFA) lesions. METHODS: A retrospective review was conducted of 97 patients (mean age 72.9±8.9 years; 63 men) who underwent IVUS examination during endovascular treatment of 112 de novo SFA lesions between July 2012 and December 2014. Self-expanding bare stents were implanted in 46 lesions and paclitaxel-eluting stents in 39 lesions. Six months after stenting, follow-up angiography was conducted to assess stent patency. The primary endpoint was angiographic ISR determined by quantitative vascular angiography analysis at the 6-month follow-up. Variables associated with restenosis were sought in multivariate analysis; the results are presented as the odds ratio (OR) and 95% confidence interval (CI). RESULTS: At follow-up, 27 (31.8%) angiographic ISR lesions were recorded. The lesions treated with uncoated stents were more prevalent in the ISR group compared with the no restenosis group (74.1% vs 44.8%, p=0.02). Lesion length was longer (154.4±79.5 vs 109.0±89.3 mm, p=0.03) and postprocedure minimum stent area (MSA) measured by IVUS was smaller (13.9±2.8 vs 16.3±1.6 mm(2), p<0.001) in the ISR group. Multivariate analysis revealed that bare stent use (OR 7.11, 95% CI 1.70 to 29.80, p<0.01) and longer lesion length (OR 1.08, 95% CI 1.01 to 1.16, p=0.04) were predictors of ISR, while increasing postprocedure MSA (OR 0.58, 95% CI 0.41 to 0.82, p<0.01) was associated with lower risk of ISR. Receiver operating characteristic analysis identified a MSA of 15.5 mm(2) as the optimal cutpoint below which the incidence of restenosis increased (area under the curve 0.769). CONCLUSION: Postprocedure MSA can predict ISR in SFA lesions, which suggests that adequate stent enlargement during angioplasty might be required for superior patency.

Impact of intravascular ultrasound findings on long-term patency after self-expanding nitinol stent implantation in the iliac artery lesion.

Although intravascular ultrasound (IVUS) predictors of stent patency for the coronary artery lesion have been established, little is known about IVUS predictors of stent patency for the aorto-iliac artery lesion. We analyzed 154 lesions of 122 patients who underwent stent implantation for iliac artery lesions. Quantitative and qualitative IVUS analyses were performed for pre- and post-procedural IVUS imaging in all lesions. Target lesion revascularization (TLR) was defined as clinically driven revascularization with >50 % angiographic stenosis of the target lesion. The mean follow-up period was 39 ± 16 months. TLRs were performed in 13 lesions (8.4 %). Post-procedural minimum stent area (MSA) was significantly smaller in the TLR group compared to the no-TLR group (16.0 ± 5.8 vs. 25.6 ± 8.5 mm(2), p < 0.001). Stent edge dissection was frequently observed in the TLR group compared to the no-TLR group (53.8 vs. 24.1 %, p = 0.04). Multivariate analysis revealed that post-procedural MSA (OR = 0.76, p < 0.01) and stent edge dissection (OR = 10.4, p < 0.01) were independent IVUS predictors of TLR. Receiver-operating characteristic analysis identified post-procedural MSA <17.8 mm(2) as the optimal cut-point for the prediction of TLR (AUC = 0.846). Post-procedural MSA and stent edge dissection could predict long-term stent patency in the iliac artery lesion. Our results propose that adequate stent enlargement without edge dissection might be important to reduce TLR in the iliac artery lesion.

Impact of spotty calcification on long-term prediction of future revascularization: a prospective three-vessel intravascular ultrasound study.

To date, there are no prospective studies on the relationship between plaque characteristics identified by 40 MHz IVUS and future adverse events. This prospective study evaluated the relationship between plaque morphology in nonculprit nonsignificant lesions, determined by 40 MHz IVUS, and long-term clinical outcomes. Consecutively, 45 patients who underwent 3-vessel intravascular ultrasound (IVUS) examinations were prospectively enrolled. Qualitative and quantitative IVUS analyses including scoring of echogenicity for assessment of plaque characterization were performed for each nonsignificant nonculprit lesion. The number, the length, the location (superficial or deep), and maximum arc were measured for each calcium deposit within plaques. Spotty calcification was defined as calcium deposits <90° and <6 mm in length. Primary end point was defined as nonsignificant nonculprit lesion-related revascularization (NNLR) during 6 years of follow-up. A total of 163 nonsignificant nonculprit lesions with mild to moderate stenosis were identified on baseline 3-vessel IVUS. Of those 163 lesions, six lesions required NNLR during the follow-up period. There were no differences in quantitative IVUS parameters including remodeling index, plaque burden, and echogenicity between lesions requiring and not requiring NNLR. However, deep spotty calcification was more frequently identified in lesions requiring NNLR than in those not requiring NNLR (33 vs. 8 %, P = 0.02). Spotty calcium deposits identified by 40 MHz IVUS predicted the need for NNLR during a 6-year follow-up period. This finding suggests that deep spotty calcium may be a surrogate marker for plaque progression and the subsequent need for revascularization in the future.

Tissue Characterization of In-Stent Neointima Using Optical Coherence Tomography in the Late Phase After Bare-Metal Stent Implantation--An Ex Vivo Validation Study.

BACKGROUND: We performed an ex vivo study to investigate optical coherence tomography (OCT) imaging for differentiating several types of neointimal tissue during the later phases after bare-metal stent (BMS) implantation as compared with histologic results. METHODS AND RESULTS: OCT imaging was performed in 6 autopsy hearts for 10 BMS with implant duration >4 years. OCT qualitative neointimal tissue characterization was based on tissue structure and classified as homogeneous pattern, heterogeneous pattern with visible struts, or heterogeneous pattern with invisible struts. Corresponding histological analyses of each 2-mm cross-section of the entire BMS were performed. Of 81 cross-sections, histological analysis revealed that the homogeneous pattern of neointima on OCT (n=39) contained smooth muscle cells with collagen, indicating high neointimal maturity. The heterogeneous patterns with visible struts (n=35) contained different tissues, including a proteoglycan-rich myxomatous matrix or dense calcified plate deposition. The heterogeneous patterns with invisible struts (n=7) included neointimal lipid/necrotic core formation, accumulation of foam cells, or microcalcification scattering. Of the 66 cross-sections containing large microvessels within the neointima on histology, only 6 (9%) were visualized by OCT. CONCLUSIONS: The present study confirmed the potential use of OCT in differentiating several types of neointima after BMS implantation. The image interpretation of OCT, based on visualization of stent struts, enables identification of several types of neointimal tissues, including in-stent fibroatheroma formation, more accurately.

Natural history of low-intensity neointimal tissue after an everolimus-eluting stent implantation: a serial observation with optical coherence tomography.

Although previous optical coherence tomography (OCT) studies reported that restenosis tissue after implantation of a drug-eluting stent (DES) was composed of a variety of cells, the clinical significance of morphologic characteristics for in-stent neointimal tissue as assessed by OCT has not been clarified. We experienced a patient with stable angina who underwent percutaneous coronary intervention with a 2.5 × 18-mm DES implantation 6 months before the OCT examination. OCT imaging showed a mild intimal hyperplasia (39 % neointimal hyperplasia) with eccentric, heterogeneous tissue, predominantly of low signal intensity. Seventeen months after the initial procedure, OCT revealed a significant increase in percent neointimal hyperplasia of 58 %, with morphologically different intimal tissue of concentric homogeneous high intensity in the stented segments. This finding suggests that low-intensity intimal tissue morphology detected by OCT could be a morphometric predictor of late neointimal tissue growth after DES implantation.

Effect of bare-metal nitinol stent implantation and paclitaxel-eluting nitinol stent implantation on vascular response in the superficial femoral artery lesion assessed on intravascular ultrasound.

BACKGROUND: Although previous intravascular ultrasound (IVUS) studies reported that the drug-eluting stent (DES) has successfully decreased in-stent restenosis (ISR) by inhibiting neointimal hyperplasia (NIH) in the coronary artery lesion, no IVUS data for vascular response after DES implantation in the superficial femoral artery (SFA) have been published. METHODS AND RESULTS: We retrospectively analyzed 38 de novo SFA lesions from 32 patients who underwent endovascular therapy (EVT) with self-expanding bare-metal nitinol stent (25 lesions; BMS group) or self-expanding paclitaxel-eluting nitinol stents (13 lesions; PES group). At 6 months after EVT, follow-up IVUS was done to evaluate NIH. Serial IVUS volumetric analysis was done after stent deployment and at follow-up. Mean stent, lumen and neointimal areas were calculated as the volume divided by the stent length. The primary endpoint of this study was mean late lumen loss at 6-month follow-up. The mean follow-up period was 189±39 days. Mean neointimal area was smaller in the PES group compared to the BMS group (3.3±1.0mm(2) vs. 10.2±4.1mm(2), P<0.001). Mean late lumen loss was significantly lower in the PES group compared to the BMS group (-2.3±3.7mm(2) vs. 2.1±4.7mm(2), P<0.05). CONCLUSIONS: EVT with DES in SFA lesions might decrease NIH associated with ISR in short-term follow-up.

Impact of post-procedural intravascular ultrasound findings on long-term results following self-expanding nitinol stenting in superficial femoral artery lesions.

BACKGROUND: Previous intravascular ultrasound (IVUS) studies have reported that a tiny reference cross-sectional area (CSA), stent under-expansion, stent asymmetry, stent edge dissection, and tissue protrusion are associated with target lesion revascularization (TLR) after coronary intervention. In the lower limb, however, it has not been reported that these findings correlate with TLR after endovascular therapy (EVT). METHODS AND RESULTS: A total of 236 consecutive superficial femoral artery (SFA) lesions in patients who underwent IVUS after self-expanding nitinol stent implantation, were analyzed. Stent expansion ratio was calculated as minimum stent CSA/reference lumen CSA, radial stent symmetry index as minimum/maximum stent diameter, and axial stent symmetry index as minimum/maximum stent CSA. TLR was defined as clinically driven revascularization with ≥75% restenosis of the target lesion. The mean follow-up period was 34±15 months. TLR were performed in 42 lesions (17.8%). There were no significant differences in stent expansion ratio, stent symmetry indices, and tissue protrusion between the TLR and no-TLR groups. Multivariate analysis indicated that total stent length (odds ratio [OR], 1.004; P<0.05), distal reference CSA (OR, 0.91; P<0.01), and stent edge dissection (OR, 3.51; P<0.01) were independent predictors of TLR. CONCLUSIONS: Stent implantation in tiny vessels and stent edge dissection in SFA lesions are indicators of high risk of TLR. Post-procedural stent under-expansion and stent asymmetry, however, were not associated with TLR.

Relation of cardiovascular risk factors and angina status to obstructive coronary artery disease according to categorical coronary artery calcium score.

Coronary artery calcium (CAC) is associated with the presence of coronary artery disease (CAD) and cardiovascular risk factors. However, the relation between cardiovascular risk factors and CAD has not yet been fully elucidated in patients with a zero or low coronary artery calcium score (CACS). The purpose of this study was to evaluate the relation of cardiovascular risk factors and angina status to obstructive CAD according to categorical CACS. A total of 753 patients were enrolled in this study. CAC scoring and coronary computed tomographic angiography (CCTA) were performed with dual-source 64-slice CT scanners. The number of patients with a CACS ≤10 and ≤100 were 358 and 528, respectively. Patients with a higher CACS were older and more frequently male, and had a greater frequency of hypertension, diabetes, and hypercholesterolemia. The prevalence of obstructive CAD increased with the CACS. Among patients with a CACS ≤100, age, male gender, diabetes, hypercholesterolemia, and typical angina pectoris were related to obstructive CAD. The presence of hypercholesterolemia was relatively strongly associated with obstructive CAD (OR 6.67, 95% CI 2.91-15.3, p < 0.001) on multivariate analysis. Among patients with a CACS ≤10, men, hypercholesterolemia, and typical angina pectoris were significantly more frequent in patients with than in those without obstructive CAD (p < 0.01). Our data suggest that neither the absence nor low of coronary calcium burden may reliably exclude obstructive CAD in typical symptomatic male patients with hypercholesterolemia. This result may be useful to interpret the relation of CACS to obstructive CAD.

Mechanisms of gradual pressure drop in angiographically normal left anterior descending and right coronary artery: Insights from wave intensity analysis.

BACKGROUND: This study evaluated the mechanism of decline in coronary pressure from the proximal to the distal part of the coronary arteries in the left anterior descending (LAD) versus the right coronary artery (RCA) from the insight of coronary hemodynamics using wave intensity analysis (WIA). METHODS: Twelve patients with angiographically normal LAD and RCA were prospectively enrolled. Distal coronary pressure, mean aortic pressure, and average peak velocity were measured at 4 different positions: 9, 6, 3, and 0 cm distal from each coronary ostium. RESULTS: The distal-to-proximal coronary pressure ratio during maximum hyperemia gradually decreased in proportion to the distance from the ostium (0.92±0.03 and 0.98±0.03 at 9 cm distal to the LAD and RCA ostium). WIA showed the dominant forward-traveling compression wave gradually decreased and the backward-traveling suction wave gradually decreased in proportion to the decrease in coronary pressure through the length of the non-diseased LAD but not the RCA. CONCLUSIONS: The pushing wave and suction wave intensities on WIA were diminished in proportion to the distance from the ostium of the LAD despite the wave intensity not changing across the length of the RCA, which may lead to gradual intracoronary pressure drop in the angiographically normal LAD.