Tetsuo Matsubara

Considerable Time From the Onset of Plaque Rupture and/or Thrombi Until the Onset of Acute Myocardial Infarction in Humans Coronary Angiographic Findings Within 1 Week Before the Onset of Infarction

BackgroundIt has been thought that the thrombi and bleeding in plaques that occur after plaque rupture or endothelial damage from vessels with mild stenosis suddenly occlude the lumen and cause acute myocardial infarction (AMI). However, our hypothesis is that thrombi and bleeding may not suddenly occlude the lumen. Methods and ResultsThe study group consisted of 20 patients who had coronary angiograms performed within 1 week (3±3 days) before AMI and 20 control patients who had coronary angiograms performed 6 to 18 months (282±49 days) before AMI. The features of infarct-related coronary segments (IRCS) at 3 days before AMI were the presence of a significant stenosis of >50% (95% in incidence and 71±12% diameter stenosis) and Ambrose’s type II eccentric lesions (plus multiple irregularities), an indicator of plaque rupture and/or thrombi (60% [70%]), and the features at 1 year before AMI were mild stenosis of <50% (95% incidence and 30±18% diameter stenosis) with rare Ambrose’s type II eccentric lesions (plus multiple irregularities) (10% [10%]). The same relation was observed in each of the 4 subgroups with Q-wave infarction, non–Q-wave infarction, preceding effort angina within 1 month before AMI, and no preceding effort angina. ConclusionsThe appearance of marked progression and Ambrose’s type II eccentric lesion on coronary angiograms 3 days before AMI suggests the presence of a considerable time from the onset of plaque rupture and/or thrombi until the onset of AMI. These features may be predictors of AMI. The concept provides new insight into the mechanism and prevention of human AMIs.

Process of progression of coronary artery lesions from mild or moderate stenosis to moderate or severe stenosis: A study based on four serial coronary arteriograms per year.

BACKGROUND The process of progression in coronary artery disease is unknown. METHODS AND RESULTS The subjects were 36 patients with 36 objective vessels with clinically significant progression of coronary artery disease (>/=15% per year) in whom 4 serial coronary arteriograms (CAGs) were performed at intervals of approximately 4 months in a 1-year period. The degree of progression of percent stenosis between each of 2 serial CAGs was classified as marked (M: >/=15%), slight (S: 5% to 14%), and no progression (N: <5%). From the pattern of progression, the 36 vessels were classified as 14 type 1 vessels with marked progression (N-->N-->M in 13 vessels and S-->S-->M in 1 vessel) and 22 type 2 vessels without marked progression (S-->S-->S in 18 vessels, N-->S-->S in 4). Percent stenosis at the first, second, third, and final CAGs was 44+/-14%, 46+/-13%, 46+/-13%, and 88+/-10% (P<0.05 versus first CAG) in type 1 vessels and 44+/-11%, 50+/-9%, 59+/-9%, and 67+/-9% in type 2 vessels (P<0.05 for second, third, and final CAGs versus first CAG). Type 1 vessels featured the sudden appearance of severe stenosis due to marked progression, angina pectoris, or myocardial infarction (71%) and Ambrose type II eccentric lesions indicating plaque rupture or thrombi (57%). Type 2 vessels featured continuous slight progression of stenosis with smooth vessel walls; angina pectoris (14%) occurred when the percent stenosis reached a severe level. An increase in serum C-reactive protein was observed only in the type 2 vessel group, which suggests a relation between continuous slight progression and inflammatory change. CONCLUSIONS Two types of stenosis progression provide a new insight into the mechanism of coronary artery disease.

Three minute, but not one minute, ischemia and nicorandil have a preconditioning effect in patients with coronary artery disease.

OBJECTIVES This study focused on 1) the determination of the optimal preconditioning (PC) duration, and 2) the protective effect of nicorandil (NC), a hybrid nitrate with a KATP channel opening effect, during a percutaneous transluminal coronary angioplasty (PTCA) model in humans. BACKGROUND The ischemic PC effect is induced in 180 s ischemia, but not in 120 s ischemia in rabbit hearts. However, the duration of ischemia that induces PC effect and the role of the KATP channel in the PC effect in humans are still unclear. METHODS Forty-six patients with stable angina were randomly allocated to four groups: the duration of the first inflation as PC ischemia was 60 s in the PC60 group (n = 12), and 180 s in the PC180 group (n = 12). In the other groups, NC (80 microg/kg) was intravenously given for 1 min in the NC group (n = 12), and isosorbide dinitrate (ISDN) (40 microg/kg) was given in the ISDN group (n = 10). Five minutes after first inflation or drug administration, a second inflation was conducted for 120 s in each group. In the ECG, the lead with the largest shift in ST segment (deltaST max), and the sum of elevated ST levels in all leads (sigmaST) were determined. RESULTS In the PC60 group, no significant difference was observed in either deltaST max or sigmaST between the first and second inflation. However, the second inflation in the PC180 group showed significantly lower levels of deltaST max and sigmaST compared with those of the first inflation. In the NC group, both deltaST max and sigmaST measured at 30 s and 60 s after balloon inflation were significantly lower than those of the first inflation in the PC60 and PC180 control groups. In the ISDN group, no significant difference was observed in deltaST max or sigmaST. CONCLUSION In human PTCA models, a PC effect is observed in 180 s ischemia, but not in 60 s ischemia. A pharmacological PC effect is induced by NC, a KATP channel opener with a nitrate-like effect but not ISDN. This suggests that the opening of KATP channels plays an important role in the protecting effect of NC.

The efficacy of a bilateral approach for treating lesions with chronic total occlusions the CART (controlled antegrade and retrograde subintimal tracking) registry.

OBJECTIVES The aim of this study was to evaluate the safety and feasibility of a new concept for chronic total occlusion (CTO) recanalization-using a bilateral approach that utilizes a Controlled Antegrade and Retrograde subintimal Tracking (CART) technique. BACKGROUND Successful percutaneous recanalization of coronary CTOs results in improved long-term outcomes. The recanalization of CTOs in native coronary arteries no doubt represents one of the most technically challenging of interventional procedures. METHODS A total of 224 consecutive patients (mean age 61 +/- 9 years; 86.2% men) were enrolled in this prospective multicenter registry. This technique combines the simultaneous use of antegrade and retrograde approaches. A subintimal dissection is created in both antegrade and retrograde fashion, thereby limiting the extension of the subintimal dissection within the CTO portion. RESULTS Of 224 CTO lesions (>3 months in duration) undergoing attempted recanalization using the CART technique, 145 cases (64.7%) had undergone previous CTO recanalization attempts. The success rates of crossing in a retrograde fashion with a wire and a balloon were 87.9% and 79.9%, respectively. The overall technical and procedural success rates achieved in this registry were 92.4% and 90.6%, respectively. CONCLUSIONS A bilateral approach for CTO lesions using the CART technique is feasible, safe, and has a higher success rate than previous approaches. These results indicate that a bilateral technique can solve a major dilemma that commonly affects CTO procedures.

Effect of fluvastatin on progression of coronary atherosclerotic plaque evaluated by virtual histology intravascular ultrasound.

OBJECTIVES The aim of this study was to evaluate the effect of treatment with statins on the progression of coronary atherosclerotic plaques of a nonculprit vessel by serial volumetric virtual histology (VH) intravascular ultrasound (IVUS). BACKGROUND Recent clinical trials have demonstrated a reduction of atherosclerotic plaque, yet whether statin therapy affects the change in components of plaque remains unknown. METHODS This study was a nonrandomized and nonblinded design. Eighty patients with stable angina pectoris were divided into either the fluvastatin group (n = 40) or the control group (n = 40) according to their total or low-density lipoprotein (LDL) cholesterol level. The volume of each plaque component (dense calcium, fibrous tissue, fibro-fatty, or necrotic core) was evaluated at baseline and at 12-month follow-up. RESULTS The LDL cholesterol and high-sensitivity C-reactive protein (hsCRP) levels in the fluvastatin group were significantly decreased at time of follow-up. In VH IVUS findings, fibro-fatty volume was significantly decreased (baseline 80.1 +/- 57.9 mm(3) vs. follow-up 32.5 +/- 27.7 mm(3), p < 0.0001) and fibrous tissue volume was increased (baseline 146.5 +/- 85.6 mm(3) vs. follow-up 163.3 +/- 94.5 mm(3), p < 0.0001) in the fluvastatin group. In the control group, the volumes of all plaque components without fibrous tissue were significantly increased. Change in fibro-fatty volume has a significant correlation with a change in LDL cholesterol level (R = 0.703, p < 0.0001) and change in hsCRP level (R = 0.357, p = 0.006). CONCLUSIONS One-year lipid-lowering therapy by fluvastatin showed significant regression of plaque volume and alterations in atherosclerotic plaque composition with a significant reduction of fibro-fatty volume.

Plaque characterisation by Virtual Histology intravascular ultrasound analysis in patients with type 2 diabetes

Objectives: To evaluate the in-vivo plaque composition and characteristics in patients with type 2 diabetes mellitus (DM) using Virtual Histology intravascular ultrasound (VH IVUS). Methods: In 90 patients with stable angina pectoris, de novo target vessels were studied and plaque components were analysed. Patients were divided into two groups: a diabetic group (36 vessels) and a non-diabetic group (54 vessels). Results: The percentage area of necrotic core and dense calcium were significantly larger in the DM group than the non-DM group (necrotic core: 11.0% (interquartile range (IQR): 7.2–15.2%) vs 7.6% (IQR 5.6–13.2%), p = 0.03; dense calcium: 5.6% (IQR: 2.3–7.3%) vs 2.9% (IQR: 1.7–4.9%), p = 0.01). The DM group presented with a significantly higher presence of at least one VH IVUS-derived thin-cap fibroatheroma (VHD-TCFA) (75% vs 41%, p = 0.001) and VH IVUS-derived fibrocalcific atheroma (VHD-FCA) (75% vs 40%, p = 0.001). In the DM group, 53% of the vessels had both VHD-TCFA and VHD-FCA, which was significantly higher than non-DM group (17%, p = 0.0004). Conclusions: Coronary plaque characteristics in DM patients showed an increased amount of dense calcium and necrotic core, as well as a higher frequency of VHD-TCFA and VHD-FCA. Atherosclerosis of the target vessel was more advanced in diabetic patients.

IVUS-guided wiring technique: Promising approach for the chronic total occlusion

We report on two cases of IVUS‐guided wiring technique performed on chronic total occlusion using stiffer wires and low‐profile intracoronary ultrasound catheter. This technique helped improve a success rate of chronic total occlusion case. Catheter Cardiovasc Interv 2004;61:381–386.

Japanese multicenter registry evaluating the retrograde approach for chronic coronary total occlusion.

This registry evaluated the current trends and outcomes associated with retrograde percutaneous coronary intervention (PCI) for chronic total occlusion (CTO).

Contemporary retrograde approach for the recanalisation of coronary chronic total occlusion: on behalf of the Japanese Retrograde Summit Group.

AIMS The retrograde approach to CTO is promising, but questions remain with regard to its wider application and the potential risks. This study evaluated the feasibility and efficacy of retrograde recanalisation of chronic total occlusion (CTO) of the coronary arteries. METHODS AND RESULTS A total of 378 consecutive patients (previously failed PCI 32.0%) who enrolled in 27 institutions in Japan underwent retrograde recanalisation for CTO. We analysed the data on lesion characteristics, procedural materials, technique used, complications and clinical outcomes. Successful retrograde recanalisation was achieved in 70.4% and the overall procedural success was 83.6%. Collateral crossing was achieved via a septal route in 68.9%, epicardial in 27.2% and bypass grafts in 2.6%, respectively. The retrograde approach was completed with implementation of reverse CART in 42.5%, direct wire crossing in 23.1%, bilateral wiring in 22.7%, and CART in 11.7%. Major and minor collateral injuries and coronary perforations were noted in 1.3%, 10.3% and 2.9% of cases, respectively. Stroke occurred in 0.3%, QWMI and emergency PCI in 0.3% of patients with successful recanalisation. CONCLUSIONS Wider application of retrograde CTO PCI achieved a high rate of success in recanalisation with an acceptable rate of complications in Japan.

Impact of Intramural Thrombus in Coronary Arteries on the Accuracy of Tissue Characterization by In Vivo Intravascular Ultrasound Radiofrequency Data Analysis

Virtual Histology (VH) intravascular ultrasound (IVUS) allows differentiation between 4 different tissue phenotypes. However, the current classification tree for analysis cannot differentiate the presence of intramural thrombus. The aim of this study was to evaluate the impact of intramural thrombus for correlative accuracy between in vitro histopathology of coronary atherosclerotic plaque obtained by directional coronary atherectomy and corresponding in vivo tissue characterization obtained by VH IVUS. Coronary IVUS imaging of 30 coronary artery lesions was obtained using a 20-MHz phased-array IVUS catheter with a motorized pull-back system at set 0.5 mm/s. The debulking region of the in vivo histologic image was predicted from comparison between pre- and post-first debulking VH IVUS images. Cross-sectional histologic slices were cut every 0.5 mm starting from the most proximal part of the formalin-fixed debulking tissue. Histologic slices were divided into 2 groups by the presence or absence of pathologic thrombus. A total of 259 in vitro histologic slices were obtained, and pathologic thrombus was detected in 81 slices. Correlation was favorable, with high sensitivity for all plaque components, but specificities for fibrous (thrombus slices vs nonthrombus slices 36% vs 94%) and fibrofatty (9% vs 60%) tissue were lower in thrombus slices. Therefore, predictive accuracies for the 2 plaque components were lower in thrombus slices (fibrous tissue 78% vs 99%, fibrofatty tissue 68% vs 83%, respectively). In conclusion, intramural thrombus was colored as fibrous or fibrofatty by VH IVUS, reducing VH accuracy in these kinds of lesions.