Motomaru Masutani

OCT Assessment of Thin-Cap Fibroatheroma Distribution in Native Coronary Arteries

OBJECTIVES We evaluated the geographic distribution of thin-cap fibroatheromas (TCFAs) in the coronary arteries using optical coherence tomography (OCT), a high-resolution imaging modality. BACKGROUND Plaque rupture is the most frequent cause of acute myocardial infarction (AMI). It has been recognized that TCFA is the primary plaque type at the site of plaque rupture. METHODS We performed 3-vessel OCT examinations in 55 patients: 35 AMI and 20 stable angina pectoris patients. The criteria for TCFA in an OCT image was a lipid-rich plaque with fibrotic cap thickness <65 microm. The distance between each TCFA location and the respective coronary artery ostium was measured with motorized OCT imaging pullback. The total length of all 3 coronary arteries imaged by OCT pullbacks was 82 +/- 21 mm in the left anterior descending coronary artery (LAD), 67 +/- 26 mm in the left circumflex coronary artery (LCx), and 104 +/- 32 mm in the right coronary artery (RCA). RESULTS OCT detected 94 TCFAs in 165 coronary arteries. The minimum fibrous-cap thickness of TCFAs was 57.4 +/- 5.4 microm in AMI patients, and 55.9 +/- 7.3 microm in stable angina pectoris patients (p = 0.4). Of the total of 94 TCFAs, 28 were detected in the LAD, 18 in the LCx, and 48 in the RCA. Most LAD TCFAs were located between 0 and 30 mm from the LAD ostium (76%). Conversely, LCx and RCA TCFAs were evenly distributed throughout the entire coronary length. The clustering of the TCFAs was similar in culprit segments as compared with nonculprit segments. In AMI patients, most LAD TCFAs were distributed near side branches, mainly positioned opposite the side branch bifurcation. CONCLUSIONS Three-vessel OCT imaging showed that TCFAs tend to cluster in predictable spots within the proximal segment of the LAD, but develop relatively evenly in the LCx and RCA arteries.

Frequency and predictor of coronary thin-cap fibroatheroma in patients with acute myocardial infarction and stable angina pectoris a 3-vessel optical coherence tomography study.

To the Editor: Autopsy studies suggest that the main mechanisms of acute myocardial infarction (AMI) are plaque ruptures followed by thrombus formation ([1][1]). Post-mortem studies have shown that rupture-prone plaques, known as thin-cap fibroatheromas (TCFAs), have certain characteristics: a thin

CorrespondenceResearch CorrespondenceFrequency and Predictor of Coronary Thin-Cap Fibroatheroma in Patients With Acute Myocardial Infarction and Stable Angina Pectoris: A 3-Vessel Optical Coherence Tomography Study

To the Editor: Autopsy studies suggest that the main mechanisms of acute myocardial infarction (AMI) are plaque ruptures followed by thrombus formation ([1][1]). Post-mortem studies have shown that rupture-prone plaques, known as thin-cap fibroatheromas (TCFAs), have certain characteristics: a thin

The Impact of Pravastatin Pre-Treatment on Periprocedural Microcirculatory Damage in Patients Undergoing Percutaneous Coronary Intervention

OBJECTIVES This study evaluated the effect of pravastatin pre-treatment on post-procedural index of microcirculatory resistance (IMR) values that are introduced for assessing the status of the microcirculation independently of the epicardial area. BACKGROUND Pre-treatment with statins decreased the incidence of cardiac enzyme increase after percutaneous coronary intervention (PCI). However, 2 different etiologies, distal embolization of atheroma or ischemia caused by side-branch occlusion, cannot be differentiated by measuring cardiac enzyme levels. METHODS Eighty patients with stable angina were randomly assigned to either pravastatin treatment (20 mg/day, n = 40) or no treatment (n = 40) 4 weeks before elective PCI. An intracoronary pressure/temperature sensor-tipped guidewire was used. Thermodilution curves were obtained during maximal hyperemia. The IMR was calculated from the ratio of the mean distal coronary pressure at maximal hyperemia to the inverse of mean hyperemic transit time. Creatine kinase-myocardial band and troponin I values were measured at baseline and at 8 and 24 h after PCI. RESULTS Post-PCI troponin I levels tended to be lower in patients with pravastatin treatment (median: 0.13 [interquartile range (IQR): 0.10 to 0.31] vs. 0.22 [IQR: 0.10 to 0.74] ng/ml, p = 0.1). However, patients with pravastatin treatment had significantly lower IMR than did patients without pravastatin treatment (median: 12.6 [IQR: 8.8 to 18.0] vs. 17.6 [IQR: 9.7 to 33.9], p = 0.007). Multivariate analysis revealed that the lack of pravastatin pre-treatment was the only independent predictor of post-PCI impaired IMR (p = 0.03). CONCLUSIONS Post-PCI measurement of the IMR confirmed that pre-treatment with pravastatin was associated with reduced microvascular dysfunction induced by PCI regardless of side branch occlusions. These data suggest that pre-treatment with statin is desired in patients undergoing elective PCI. (The Impact of Pravastatin Pretreatment on Periprocedural Microcirculatory Damage After Percutaneous Coronary Intervention; UMIN000002885).

Endothelium-dependent coronary vasomotor response and neointimal coverage of zotarolimus-eluting stents 3 months after implantation

Background Zotarolimus-eluting stents (ZES) have a higher rate of neointimal coverage than the first-generation drug-eluting stents on optical coherence tomography (OCT). Objective To determine whether neointimal coverage of stent struts detected by OCT can be used as a surrogate for endothelial function after ZES implantation. Design Cross-sectional observational study. Setting Three months after ZES implantation. Patients and methods OCT was performed in 20 patients with a ZES at 3 months after stent implantation to evaluate strut coverage. Endothelium-dependent coronary vasomotion was estimated by infusing incremental doses of acetylcholine into the coronary ostium. The vascular response was measured in the 10 mm segments proximal and distal to the stent. Results Of 20 ZES, 15 (75%) were covered completely with neointima, but the remaining 5 ZES had exposed struts. The high-dose acetylcholine infusion produced significant vasoconstriction in the proximal (−9.8±10.1%) and the distal stent segment (−29.7±22.7%). However, the degree of vasoconstriction to acetylcholine varied between individuals (from −0.6% to −77%). Although no relationship was observed between coronary vasomotor response (percentage change in diameter after acetylcholine administration) and average neointimal thickness, the number of cross-sections with uncovered struts showed an inverse correlation with coronary vasomotor response in proximal and distal stent segments (r=−0.57, p=0.007 and r=−0.83, p<0.001, respectively). Conclusions The existence of exposed struts was associated with abnormal vasoconstriction to acetylcholine at 3 months after ZES implantation. The findings suggest that complete neointimal coverage of stent struts assessed by OCT could be used as a surrogate for vasomotion impairment at 3 months after ZES implantation.

Effect of Culprit-Lesion Remodeling Versus Plaque Rupture on Three-Year Outcome in Patients With Acute Coronary Syndrome

To investigate intravascular ultrasound predictors of long-term clinical outcome in patients with acute coronary syndrome, 94 patients with a first acute coronary syndrome with both preintervention intravascular ultrasound imaging and long-term follow-up were enrolled in this study. Remodeling index was defined as external elastic membrane cross-sectional area at the target lesion divided by that at the proximal reference. Arterial remodeling was defined as either positive (PR: remodeling index >1.05) or intermediate/negative remodeling (remodeling index < or =1.05). Clinical events were death, myocardial infarction, and target-lesion revascularization. Patients were followed up for a mean of 3 years. PR was observed in 50 (53%), and intermediate/negative remodeling, in 44 (47%). During the 3-year follow-up, there were 20 target-lesion revascularization events and 5 deaths (2 cardiac and 3 noncardiac), but no myocardial infarctions. Patients with PR showed significantly lower major adverse cardiac event (MACE; death, myocardial infarction, and target-lesion revascularization)-free survival (log-rank p = 0.03). However, patients with plaque rupture showed a nonsignificant trend toward lower MACE-free survival (p = 0.13), but there were no significant differences in MACE-free survival between those with single versus multiple plaque ruptures. Using multivariate logistic regression analysis, only culprit lesion PR was an independent predictor of MACEs (p = 0.04). In conclusion, culprit-lesion remodeling rather than the presence or absence of culprit-lesion plaque rupture was a strong predictor of long-term (3-year) clinical outcome in patients with acute coronary syndrome.

A prospective multicenter registry of 0.010-inch guidewire and compatible system for chronic total occlusion: The PIKACHU registry†

Objectives: The aim of this study was to evaluate the safety and effectiveness of a 0.010‐inch guidewire and a balloon catheter for treatment of chronic total occlusion (CTO). Background: Pathological studies have shown that 60–70% of CTO lesions have microchannels of sizes equal to or less than 0.010 inch. Methods: The PIKACHU registry is a prospective, multicenter registry study. A 0.010‐inch guidewire had to be used as the first guidewire to attempt to pass the CTO lesion. The primary endpoint was device success using a 0.010 system. Results: A total of 141 patients with 141 lesions were enrolled. The median duration of occlusion was 9 months (range 3–156). Average guiding catheter size was 5.8 ± 0.7 Fr. and TRI was 76.6 %. CTOs were mostly between 10–20 mm long, observed in 53 occlusions. There were 107 lesions (75.9%) with bending of more than 45 degrees. Calcification was seen in 91 lesions (64.5%). A 0.010‐inch guidewire was successfully passed through in 97 of 141 lesions (68.8%). A 0.010‐inch guidewire compatible balloon catheter was passed in 87 of the 97 lesions (88.7%) and final PCI success was achieved in all the cases. The overall clinical success rate was 87.9% (124/141). No MACE or bleeding complications were observed. Conclusion: The PIKACHU registry data suggest that the 0.010‐inch system is safe and practicable for treatment of CTO lesions.

A new 0.010‐inch guidewire and compatible balloon catheter system: The IKATEN registry

To evaluate the safety and feasibility of a new 0.010‐inch guidewire and a specialized balloon catheter for the 0.010‐inch guidewire in routine percutaneous coronary intervention (PCI).

Comparison of Frequency of Radial Artery Occlusion After 4Fr Versus 6Fr Transradial Coronary Intervention (from the Novel Angioplasty USIng Coronary Accessor Trial)

The frequency of radial artery occlusion was compared between patients receiving 4Fr versus 6Fr transradial coronary interventions (TRIs) in an open-label randomized trial (ClinicalTrials.gov identifier: NCT00815997). The primary outcome measure was radial artery occlusion on the day after TRI. The secondary outcome measures were the procedural success, major advanced cardiac events, access site-related complications, procedural times, fluoroscopy times, and contrast dye usage. A total of 160 patients were included. The procedure was successful in 79 of 80 patients (99%) in both groups. Whereas the 4Fr group showed no access site-related complications, the 6Fr developed 5 (6%), including 3 radial artery occlusions and 2 bleedings (1 radial artery perforation and 1 massive hematoma; p = 0.02). Although the radial artery occlusion rate was lower in the 4Fr versus the 6Fr groups, the difference was not significant (0% vs 4%, p = 0.08). The mean hemostasis time was significantly shorter in the 4Fr than in the 6Fr groups (237 ± 105 vs 320 ± 238 minutes, p = 0.007). In conclusion, these findings suggest that 4Fr TRI may become a less invasive alternative to 6Fr TRI in treating coronary artery diseases.

Novel use of ultrasound guidance for recanalization of iliac, femoral, and popliteal arteries

Objectives: We attempted to demonstrate the safety and feasibility of intravascular ultrasound (IVUS)‐guided endluminal endovascular therapy for chronic total occlusion (CTO) of the iliac and/or femoropopliteal arteries using Treasure 12, a stiff guidewire for peripheral CTO of 0.018 in. in monodirectional approach setting. Background: Endovascular therapy for CTO of the iliac and femoropopliteal arteries is still technically challenging. Methods: Endovascular therapy was performed in 110 patients who were admitted to Hyogo College of Medicine Hospital with iliac and/or femoropopliteal artery disease from January 2006 to October 2007. We retrospectively analyzed the data of consecutive 47 patients who underwent the endovascular therapy by monodirectional approach for CTO lesions of the iliac and femoropopliteal arteries. From January 2006 to November 2006 (phase 1), standard technique was applied for the treatment of 21 lesions. From December 2006 to October 2007 (phase 2), IVUS‐guided endovascular therapy was applied for the treatment of 31 lesions. Results: Clinical and lesion characteristics in phase 1 were not significantly different from those in phase 2. The overall initial technical success rate improved from 81% in phase 1 to 97% in phase 2. There were no significant differences in radiation exposure time between phase 1 and phase 2. Total volume of contrast material was significantly smaller in phase 2 than in phase 1 (P < 0.01). Conclusions: The IVUS‐guided endovascular therapy for CTO using Treasure 12 guidewire is feasible and safe, minimizes contrast material, and has a high initial technical success rate.