Yosuke Katayama

Optical Coherence Tomography Predictors for Edge Restenosis After Everolimus-Eluting Stent Implantation

Background—Stent edge restenosis (SER) remains a potential limitation of drug-eluting stents. The aim of this study was to determine optical coherence tomography (OCT) predictors for angiographic late SER after everolimus-eluting stent implantation. Methods and Results—We retrospectively analyzed 319 patients who underwent OCT immediately after everolimus-eluting stent implantation and scheduled 9- to 12-month follow-up angiography. The binary angiographic SER rate was 10% (32/319) in the patients, 8.4% (32/382) in lesions, and 4.4% (33/744) in stent edge segments. In the stent edge segments at post stenting, OCT-derived lipidic plaque (61% versus 20%; P<0.001) was more often observed in the SER group, and OCT-measured minimum lumen area (4.13±2.61 versus 5.58±2.46 mm2; P=0.001) was significantly smaller in the SER group compared with the non-SER group. Multivariate analysis identified lipidic plaque (odds ratio: 5.99; 95% confidence interval: 2.89–12.81; P<0.001) and minimum lumen area (odds ratio: 0.64; 95% confidence interval: 0.42–0.96; P=0.029) as independent predictors of binary SER. Receiver-operating characteristic analysis demonstrated that lipid arc of 185° (sensitivity: 71%; specificity: 72%; area under the curve: 0.761) and minimum lumen area of 4.10 mm2 (sensitivity: 67%; specificity: 77%; area under the curve: 0.787) were optimal cutoff values for predicting ischemia-driven SER. Conclusions—The present OCT study demonstrated that lipidic plaque and minimum lumen area in the stent edge segments at post stenting were associated with late SER after everolimus-eluting stent implantation. OCT provides valuable information to determine an appropriate landing zone for stent implantation.

Reduction of in-stent thrombus immediately after percutaneous coronary intervention by pretreatment with prasugrel compared with clopidogrel: An optical coherence tomography study.

BACKGROUND Prasugrel is a new-generation thienopyridine antiplatelet agent that provides more consistent and prompt platelet inhibition than clopidogrel. The aim of this study was to compare in-stent thrombus inhibition effect of pretreatment with prasugrel and clopidogrel by using optical coherence tomography (OCT) immediately after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). METHODS We performed OCT immediately after PCI in 108 ACS patients pretreated with either prasugrel (n=51) or clopidogrel (n=57). OCT detected thrombus/plaque protrusion in all stented segments. RESULTS Although stent volume (190.4±119.1mm3 vs. 189.4±95.8mm3, p=0.961), mean stent area (6.9±2.9mm2 vs. 7.1±2.0mm2, p=0.772), and minimum stent area (5.6±2.7mm2 vs. 5.4±1.7mm2, p=0.554) were not different between the two groups, in-stent thrombus/plaque protrusion volume (1.8±2.9mm3 vs. 4.5±5.3mm3, p=0.002), mean in-stent thrombus/plaque protrusion area (0.1±0.1mm2 vs. 0.2±0.2mm2, p=0.005), and maximum in-stent thrombus/plaque protrusion area (0.5±0.7mm2 vs. 0.8±0.6mm2, p=0.007) were significantly smaller in the prasugrel group compared with the clopidogrel group. CONCLUSIONS Pretreatment with prasugrel was associated with significantly reduced in-stent thrombus/plaque protrusion immediately after PCI for ACS compared with that with clopidogrel.

Impact of functional focal versus diffuse coronary artery disease on bypass graft patency

BACKGROUND Pressure guidewire pullback recording can differentiate between functional focal and diffuse disease types in coronary artery disease. The aim of this study was to compare the outcome of coronary artery bypass graft (CABG) patency between patients with functional focal versus diffuse disease types in recipient coronary arteries. METHODS AND RESULTS We investigated 89 patients who underwent pressure guidewire pullback in the left anterior descending (LAD) artery before CABG using internal mammary artery (IMA). Based on the pressure guidewire pullback data, the LAD lesions were classified into functional focal disease (abrupt pressure step-up; n=58) or functional diffuse disease (gradual pressure increase; n=31). Follow-up computed tomography (CT) angiography was conducted within 1year after CABG to assess the bypass graft patency. Pre CABG, LAD angiographic percent diameter stenosis (57±10% vs. 54±12%, p=0.228) and fractional flow reserve (FFR) (0.68±0.07 vs. 0.69±0.07, p=0.244) were not different between the functional focal and diffuse disease groups. The CABG procedure characteristics were similarly comparable between the two groups. In the follow-up CT angiography after CABG, occlusion or string sign of the IMA graft to LAD was more frequently observed in the functional diffuse disease group than in the functional focal disease group (26% vs. 7%, p=0.021). CONCLUSION In CABG, functional diffuse disease in the recipient coronary artery was associated with an increased risk of the graft failure in comparison with functional focal disease.

Diagnostic Accuracy of Quantitative Flow Ratio for Assessing Myocardial Ischemia in Prior Myocardial Infarction

BACKGROUND A novel index of the functional severity of coronary stenosis, quantitative flow ratio (QFR), may not consider the amount of viable myocardium in prior myocardial infarction (MI) because QFR is calculated from 3D quantitative coronary angiography.Methods and Results:We analyzed QFR (fixed-flow QFR [fQFR] and contrast-flow QFR [cQFR]) and fractional flow reserve (FFR) in prior-MI-related coronary arteries (n=75) and non-prior-MI-related coronary arteries (n=75). Both fQFR and cQFR directly correlated with FFR in the prior-MI-related coronary arteries (fQFR: r=0.84, P<0.001; and cQFR: r=0.88, P<0.001) and the non-prior-MI-related coronary arteries (fQFR: r=0.91, P<0.001; and cQFR: r=0.94, P<0.001). fQFR was significantly smaller than FFR in the prior-MI-related coronary arteries (0.73±0.14 vs. 0.79±0.11, P=0.002), but there was no significant difference between fQFR and FFR in the non-prior-MI-related coronary arteries. The value of cQFR minus FFR was significantly lower in the prior-MI-related coronary arteries compared with the non-prior-MI-related coronary arteries (-0.02±0.06 vs. 0.00±0.04, P=0.010). The diagnostic accuracy of fQFR ≤0.8 and cQFR ≤0.8 for predicting FFR ≤0.80 was numerically lower in the prior-MI-related coronary arteries compared with the non-prior-MI-related coronary arteries (fQFR: 77% vs. 87%; and cQFR: 87% vs. 92%). CONCLUSIONS When FFR is used as the gold standard, the accuracy of QFR for assessing the functional severity of coronary stenosis might be reduced in the prior-MI-related coronary arteries compared with non-prior-MI-related coronary arteries.

Two-year vascular responses to drug-eluting stents with biodegradable polymer versus durable polymer: An optical coherence tomography sub-study of the NEXT

BACKGROUND This study aimed to compare very late vascular response after stent implantation between everolimus-eluting stent (EES) with a thin, non-adhesive, durable, biocompatible fluorinated polymer and biolimus-eluting stent (BES) with a biodegradable polymer by optical coherence tomography (OCT). METHODS AND RESULTS In the NOBORI-BES Versus XIENCE V/PROMUS-EES Trial (NEXT), a formal OCT substudy investigated 48 patients (27 EES-treated lesions in 23 patients and 28 BES-treated lesions in 25 patients) with 2-year (18-30 months) follow-up imaging at 18 centers. The percentage of uncovered strut by neointima was significantly lower in EES compared with BES (2.1±4.7% vs. 7.9±10.8%, p=0.013). The percentage of malapposed strut was not different between EES and BES (0.1±0.3% vs. 0.5±1.3%, p=0.138). The frequency of stent with evagination, which is identified as outward bulges in the luminal contour between struts, was significantly lower in EES compared with BES (22% vs. 86%, p<0.001). The frequency of neoatherosclerosis was not different between EES and BES (11% vs. 11%, p=1.000). CONCLUSIONS At 2 years after stent implantation, uncovered stent strut by neointima and evagination were less frequently observed in EES compared with BES. This OCT study suggests that the very late vascular response is different between EES and BES.

Effects of intravenous bolus injection of nicorandil on renal artery flow velocity assessed by color Doppler ultrasound

BACKGROUND Previous animal studies have shown that a potassium channel opener, nicorandil, provokes vasodilation in renal microvasculature and increases renal blood flow. We conducted a clinical study that aimed to evaluate the effect of nicorandil on renal artery blood flow in comparison with nitroglycerin by using color Doppler ultrasound. METHODS The present study enrolled 40 patients with stable coronary artery disease who had no renal arterial stenosis and renal parenchymal disease. The patients received intravenous administration of nicorandil (n=20) or nitroglycerin (n=20). Before and after the administration, renal artery blood flow velocity was measured by color-guided pulsed-wave Doppler. RESULTS The peak-systolic, end-diastolic, and mean renal artery blood flow velocities before the administration were not different between the nicorandil group and the nitroglycerin group. The peak-systolic (79±15cm/s to 99±21cm/s, p<0.001; and 78±19cm/s to 85±19cm/s, p=0.004), end-diastolic (22±5cm/s to 28±8cm/s, p<0.001; and 24±6cm/s to 26±6cm/s, p=0.005) and mean (41±6cm/s to 49±9cm/s, p<0.001; and 43±9cm/s to 45±9cm/s, p=0.009) renal artery flow velocities increased significantly in either group. The nominal changes in the peak-systolic (20±10cm/s vs. 7±8cm/s, p<0.001), end-diastolic (5±4cm/s vs. 2±3cm/s, p=0.001), and mean (8±5cm/s vs. 2±2cm/s, p<0.001) renal artery blood flow velocities were significantly greater in the nicorandil group compared with the nitroglycerin group. CONCLUSION Intravenous nicorandil increased renal artery blood flow velocity in comparison with nitroglycerin. Nicorandil has a significant effect on renal hemodynamics.

Three-vessel fractional flow reserve measurement for predicting clinical prognosis in patients with coronary artery disease

Coronary artery disease is a common form of heart disease affecting large numbers of people across the world. Coronary artery disease is caused by atherosclerosis that narrow the coronary artery lumen and limit myocardial blood supply.

COMPARISON OF IN-STENT THROMBUS IMMEDIATELY AFTER PERCUTANEOUS CORONARY INTERVENTION FOR ACUTE CORONARY SYNDROME BETWEEN PATIENTS PRETREATED WITH PRASUGREL VERSUS CLOPIDOGREL BY USING OPTICAL COHERENCE TOMOGRAPHY

Prasugrel is a new-generation thienopyridine antiplatelet agent that provides more consistent and prompt platelet inhibition than clopidogrel. The aim of this study was to compare in-stent thrombus inhibition effect of pretreatment with prasugrel and clopidogrel by optical coherence tomography (OCT

FEASIBILITY OF OPTICAL CORONARY TOMOGRAPHY IN QUANTITATIVE MEASUREMENT OF CORONARY ARTERIES WITH LIPIDIC PLAQUE

Optical coherence tomography (OCT) has a shallower penetration depth than intravascular ultrasound (IVUS). Near-infrared light employed in OCT is attenuated by lipidic plaque. The aim of the present study was to evaluate the feasibility of OCT for measurement of vessel area in coronary arteries with