Masami Sakurada

Angioscopic coronary macromorphology in patients with acute coronary disorders.

To investigate the pathogenesis of acute coronary disorders and to clarify what type of plaque precedes these disorders, percutaneous transluminal coronary angioscopy, by means of a new angioscope, was carried out during catheterisation in 100 consecutive patients anatomically suitable for such investigations. The quality of the angioscopic image was good enough for analysis in 84 patients (14 with acute myocardial infarction [within 8 h of onset], 16 with recent myocardial infarction [3 days-2 months since onset], 24 with old myocardial infarctions, 10 with unstable angina, and 20 with stable angina). Thrombi were observed in most patients with acute coronary disorders (all 14 with acute myocardial infarction, 9 of 10 with unstable angina). Occlusive thrombi were more common in patients with acute myocardial infarction than in those with unstable angina (11 [79%] vs 1 [10%]; p less than 0.001), whereas mural (non-occlusive) thrombi were more common in the unstable angina than in the acute myocardial infarction group (8 [80%] vs 3 [21%]; p less than 0.001). Xanthomatous ulcerated plaques or ragged irregular surfaces were seen in patients with acute coronary disorders and in those with recent myocardial infarction. Xanthomatous plaques were more common in patients with acute coronary disorders (50%) than in those with stable angina (15%) or old myocardial infarction (8%). By contrast white and smooth plaques were seen in cases of stable angina and old myocardial infarction. Angioscopy could display the intracoronary lumen more precisely than could coronary arteriography. This angioscopic study suggested that, although a thrombus overlying a rupture in the lining of the plaque was common in both unstable angina and acute myocardial infarction, the character of the thrombus may differ between these disorders, and lipid-rich xanthomatous plaque may precede rupture.

Upfront thrombus aspiration in primary coronary intervention for patients with ST-segment elevation acute myocardial infarction: report of the VAMPIRE (VAcuuM asPIration thrombus REmoval) trial.

OBJECTIVES This study evaluated safety and efficacy of upfront thrombus aspiration during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Distal embolization during primary PCI results in reduced myocardial perfusion and poor clinical outcomes. METHODS The VAMPIRE (VAcuuM asPIration thrombus REmoval) study was a prospective, randomized, controlled multicenter trial conducted in 23 institutions. Patients (N = 355) presenting within 24 h of STEMI symptoms onset were randomized to primary PCI with (n = 180) or without (n = 175) upfront thrombus aspiration using Nipros TransVascular Aspiration Catheter (Osaka, Japan). RESULTS The TransVascular Aspiration Catheter reached the lesion in 100% of cases. It successfully crossed the target obstruction in 86% without any delay in procedure time or time to reperfusion; whereas macroscopic thrombi were removed in 75% of the cases. Procedure success was similar between groups (98.9% vs. 98.3%). There was a trend toward lower incidence of slow or no reflow (primary end point-defined as a Thrombolysis In Myocardial Infarction flow grade <3) in patients treated with aspiration versus conventional primary PCI (12.4% vs. 19.4%, p = 0.07). Rate of myocardial blush grade 3 was higher in the aspiration group (46.0% vs. 20.5%, p < 0.001). Aspiration was most effective in patients presenting after 6 h of symptoms onset (slow flow rate: 8.1% vs. 37.6%, p = 0.01). CONCLUSIONS This study suggested the safety of primary PCI with upfront thrombectomy using a novel device in patients with STEMI. The study showed a trend toward improved myocardial perfusion and lower clinical events in patients treated with aspiration. Patients presenting late after STEMI appear to benefit the most from thrombectomy.

Incidence and impact on midterm outcome of controlled subintimal tracking in patients with successful recanalisation of chronic total occlusions: J-PROCTOR registry.

AIMS To assess the incidence and impact on clinical outcomes of subintimal tracking in patients undergoing percutaneous coronary intervention for chronic total occlusion (CTO). Patients at 27 centres were consecutively enrolled when guidewire crossing of the CTO by either the antegrade or the retrograde approach was confirmed by intravascular ultrasound (IVUS). IVUS images were examined to identify the course of the wire. Clinical follow-up at one year and angiographic follow-up at nine months were performed after everolimus-eluting stent implantation. Among a total of 163 patients (59 antegrade and 104 retrograde), subintimal tracking was more frequent with the retrograde approach (24.2% vs. 12.3%, p=0.10). Although there was no difference in the one-year target vessel revascularisation rate between intimal and subintimal tracking with either the antegrade or the retrograde approach, angiographic follow-up revealed greater late loss in the subintimal group compared with the intimal group. Multivariate analysis identified the pre-procedural reference diameter as a predictor of subintimal tracking. Subintimal tracking was more frequent with the retrograde approach. After medium-term follow-up, no negative clinical impact of subintimal tracking was observed in this small study. However, further evaluation of the angiographic impact is needed.

Acute effects of short-term intimal heating by laser-heated thermal balloon angioplasty in canine stenotic femoral arteries in vivo

Short-term intimal heating may be effective to improve luminal geometry without deep medial injury which can induce restenosis. We developed a new laser-heated thermal balloon catheter which can quickly raise and lower the balloon temperature. To investigate the acute effect of short-term thermal balloon angioplasty (STBA) for stenotic lesions, we performed STBA following balloon angioplasty (BA) in 8 canine stenotic femoral arteries. Cw Nd:YAG laser delivery (10 W, 15 s) induced the maximum temperature of 83 degree(s)C on average. Angiography and angioscopy were performed at pre-BA, post-BA and post-STBA. The angiographical mean stenotic diameter was 1.8 mm at pre-BA, 2.2 mm* at post-BA, 2.9 mm** at post-STBA (*:p < 0.05 pre-BA vs post-BA, **:p < 0.05 pre- and post-BA vs post-STBA). The angioscopic observation revealed intimal flaps and tears in 7 lesions after BA. The luminal geometry after STBA was symmetrically expanded. However, the intimal injury was still observed although the intimal flaps were partly sealed by STBA. These results suggested that the dilatation mechanism of STBA for stenotic lesions might be attributed to preventing elastic recoil rather than to sealing intimal fragments induced by BA.

Parametric study for laser hot balloon angioplasty to suppress chronic restenosis: animal experiment

To suppress restenosis after the percutaneous transluminal coronary angioplasty (PTCA), we experimentally investigated the optimum parameter setting on the combination of the balloon temperature and heating duration of our laser hot balloon catheter in rabbit model. The rabbit femoral arteries were treated by our laser hot balloon of 2.5 mm in diameter with various balloon temperatures and durations at the range from 60 to 90 deg., and from 15 to 30 seconds, respectively. The histological examination showed that high temperature (greater than 70 deg.) was necessary to suppress hyperplasia of the vessel in chronic phase. The angiography of pre- and post-treatment and of 2 months after the treatment showed that high temperature with short heating duration (15-30 s) was the best setting for chronic patency of the treated vessels. The laser hot balloon angioplasty with the above mentioned parameter setting might realize significant improvement on chronic patency after PTCA.

PROMUS STENT TREATMENT OF CHRONIC TOTAL OCCLUSIONS USING TWO DIFFERENT RECANALIZATION TECHNIQUES IN JAPAN– J–PROCTOR REGISTRY: A MULTICENTER REGISTRY TO EVALUATE CLINICAL OUTCOME OF DRUG ELUTING STENT IN SUBINTIMAL AREA AFTER CTO REVASCULARIZATION USING ANTEGRADE OR RETROGRADE APPROACH

Since the current retrograde approach for percutaneous coronary interventions in chronic total occlusions (CTO) was introduced in 1995, this approach has continued to increase PCI success rates in CTOs. Despite the increased success rate, short and long term Drug Eluting Stent (DES) clinical

Combined guidance technique using angioscope and fluoroscope images for CO laser angioplasty: in-vivo animal experiment

The combined guidance technique using angioscope and fluoroscope (i.e. angiography) images for CO laser angioplasty was demonstrated in vivo animal experiment. The newly developed total occlusion model which has been produced by a long term transplantation of ChitinR tube in canine femoral artery was ablated by the contact irradiation of CO laser. A thin laser angioscope catheter, 5F in outer diameter, was inserted from total carotid artery to femoral artery by selective catheterization technique under fluoroscopy. A thin CO laser cable of which diameter was less than 0.6mm was advanced from the tip of the angioscope catheter. A As-S chalcogenide glass fiber of which diameter was 200micrometers was installed in the laser cable. The laser cable connected to the CO laser device which was developed for medical use. The angioscope catheter and laser cable could be seen by the fluoroscopy. The authors used the angioscope image of the occlusion end and the angiography image to check the direction of ablation hole. The simultaneous use of these images which include quite different kinds of information was extremely useful for the safety guidance of laser angioplasty for total occlusion. The histological specimen from the ablated occlusion showed that the repetitive ablation procedure made a larger lumen than the laser cable diameter.

The laser driven short-term heating balloon catheter: Relation between the chronic neointimal hyperplasia formation and thermal damage to arterial smooth muscle cells

We proposed a novel laser-driven short-term heating angioplasty to realize restenosis-suppressive angioplasty for peripheral artery disease. In this study, we investigated the chronic intimal hyperplasia formation after the short-term heating dilatation in vivo, as well as the thermal damage calculation on arterial smooth muscle cells (SMCs). The prototype short-term heating balloon catheter with 5.0, 5.5, 6.0 mm φ in balloon diameter and 25mm in balloon length were employed. The short-term heating dilatation was performed in porcine iliac arteries with dilatation conditions of 75°C (N=4) and 65°C (N=5) as peak balloon temperature, 18± 4s as heating duration, 3.5atm as balloon dilatation pressure. Four weeks after the balloon dilatation, the balloon-dilated artery segments were extracted and were stained with HE and picrosirius red for histological observation. In the case of 75°C as the peak balloon temperature, neointimal hyperplasia formation was significantly reduced. In this case, the SMCs density in the artery media measured from the HE-stained specimen was 20% lower than that in the reference artery. According to the thermal damage calculation, it was estimated that the SMCs lethality in artery media after the short-term heating angioplasty was 20% in the case of 75°C as the peak balloon temperature. We demonstrated that the short-term heating dilatation reduced the number of SMCs in artery media. We think this SMCs reduction might contribute to the suppression of chronic neointimal hyperplasia.

Whole-heart dipyridamole stress first-pass myocardial perfusion MRI for the detection of coronary artery disease with and without prior myocardial infarction

A whole-heart coverage MRI sequence, which employes a hybrid of fast gradient echo and echo planar acquisition imaging (FastCard EchoTrain), has recently been developed. Using this sequence, a first-pass myocardial perfusion MRI was shown to be a good noninvasive modality for detecting coronary artery disease (CAD) in a clinical setting. In addition, the clinical usefulness of delayed enhanced MRI has recently been reported. The objectives of this study were (1) to investigate the accuracy of dipyridamole stress first-pass myocardial perfusion MRI for diagnosing CAD (> 50% stenosis) and (2) to clarify whether additional delayed enhancement MRI has any clinical significance. We performed first-pass myocardial perfusion MRI in 102 consecutive patients (66 +/- 9 years old) suspected to have CAD or new lesions in patients with well-documented prior myocardial infarction (MI). Using a 1.5 T cardiac MR imager (GE CV/i), eight short axis MR images of the left ventricle were acquired by injecting gadolinium (0.1 mmol/kg) under dipyridamole infusion stress (0.56 mg/kg). Fifteen minutes later, aminophylline (250 mg) was injected and first-pass perfusion MRI was repeated in the resting state in order to evaluate both the presence of perfusion defect and delayed enhancement. The presence of perfusion defect and delayed enhancement was determined based on a visual qualitative analysis by the agreement of two separate readers who were blinded to any clinical information. Based on the stress and rest findings, no defect, reversible defect, or fixed defect with or without delayed enhancement was recorded in any patient. The MR findings revealed 76 CAD patients, including 24 MI patients with new lesions and 26 patients without CAD on coronary angiography. The presence of stress perfusion defect had a 93% sensitivity and an 85% specificity for diagnosing CAD. A fixed defect showed an 86% sensitivity and a 66% specificity for diagnosing a prior MI. Patients with a fixed defect with delayed enhancement had more significant stenosis in the infarct related artery than in those without any enhancement (11/26 vs 15/20, P < 0.05). Dipyridamole stress first-pass myocardial perfusion MRI using the FastCard EchoTrain was found to be a clinically useful and accurate modality for diagnosing CAD.

State of the art of CO laser angioplasty system

A unique percutaneous transluminal coronary angioplasty system new IR therapy laser with IR glass fiber delivery under novel angioscope guidance was described. Carbon monoxide (CO) laser emission of 5 mm in wavelength was employed as therapy laser to achieve precise ablation of atheromatous plaque with a flexible As-S IR glass fiber for laser delivery. We developed the first medical CO laser as well as As-S IR glass fiber cable. We also developed 5.5 Fr. thin angioscope catheter with complete directional manipulatability at its tip. The system control unit could manage to prevent failure irradiations and fiber damages. This novel angioplasty system was evaluated by a stenosis model of mongrel dogs. We demonstrated the usefulness of our system to overcome current issues on laser angioplasty using multifiber catheter with over-the-guidewire system.