Masamichi Wada

Chronic stent recoil plays an important role in restenosis of the right coronary ostium.

ObjectiveThe efficacy of coronary stenting of aorto-ostial atherosclerotic lesions is still unclear. We investigated the frequency and mechanism of stent restenosis at this particular lesion. MethodsFifty-five consecutive patients with 64 native aorto-ostial lesions in the right coronary artery (RCA, n=38) and the left main trunk (LM, n=26) were treated by conventional stenting. Determinants of angiographic restenosis were established. The mechanism of stent restenosis was evaluated using post-stenting and follow-up intravascular ultrasound (IVUS) findings. ResultsRestenosis was more frequent in the RCA than in the LM (50% compared with 19%, P<0.03) and determinants included diabetes mellitus (63% compared with 21%, P<0.03), calcium deposition (58% compared with 5%, P<0.003), smaller stent cross-sectional area (SA) (as demonstrated by post-stenting IVUS studies, 8.1±1.4 mm2 compared with 10.2±2.2 mm2, P<0.01), larger plaque burden (64±6% compared with 57±8%, P<0.03) and less circular expansion at the aorto-coronary junction. Serial IVUS examination was performed in 11 patients with restenosis of the right coronary ostium. The mean reduction in the SA was 21% at the aorto-coronary junction (6.4±1.9 mm2, P<0.003), whereas the SA at the distal edge was unchanged. Thirty-three per cent of late luminal loss was due to chronic stent recoil. ConclusionThese findings suggest that stenosis of the right coronary ostium is a high-risk lesion for stent restenosis. In addition to excessive intimal growth, chronic stent recoil might be an important etiologic factor at this particular location.

Ultrasound attenuation behind coronary atheroma without calcification: Mechanism revealed by autopsy

When performing intravascular ultrasound studies, the backward echo image can show marked attenuation, although there are no calcified deposits and it may be impossible to detect the intraplaque architecture. The pathology underlying this phenomenon was investigated in autopsy specimens. We hypothesize that the mechanism responsible for the attenuation involves micro‐calcification and lipid in unstable plaques causing ultrasonic wave reflection and dispersion.

Aggressive statin therapy in multicenter and effectiveness for the reduction of intra-myocardial damage caused by non-ST elevation acute coronary syndrome: AMERICA study

Background: While preprocedural statin treatment for acute coronary syndrome (ACS) is widely regarded as beneficial, there has been no prospective randomized multicenter trial of patients with non-ST elevation ACS in the Japanese population to examine the efficacy of preprocedural aggressive statin use. The aim of this study was to confirm this effect by prospective randomized multicenter design. Methods: Fifty patients who presented with non-ST elevation ACS were enrolled, and randomly assigned to aggressive statin administration before percutaneous coronary intervention (PCI). Troponin-T (TnT), creatine phosphokinase (CK), CK-myocardial band (CK-MB), high-sense C-reactive protein (hs-CRP), and brain natriuretic peptide (BNP) were measured at baseline and/ or after procedure. Results: Three days after PCI, the statin group had significantly less CK elevation compared with the nonstatin group (84±17 IU/l versus 180±68 IU/l, respectively, p = 0.02). CK-MB elevation also tended to be lower in the statin group than in the nonstatin group (3.2±1.9 versus. 7.0±3.0, respectively, p = 0.07), as was BNP level (3.2±1.9 versus 7.0±3.0 pg/ml, respectively, p = 0.07). The change of serum LDL cholesterol was significantly correlated with CK (p = 0.01) and TnT (p = 0.02) at 1 day after PCI. Conclusions: Aggressive statin usage before PCI to Japanese patients with non-ST elevation ACS appears to reduce myocardial damage after procedure. The degree of serum lipid level reduction may reflect the vulnerability of atheromatous plaques that could cause cardiac damage after PCI.

Cutting balloon angioplasty is superior to balloon angioplasty or stent implantation for small coronary artery disease.

The aim of this study is to demonstrate initial results and long-term outcomes of patients after receiving cutting balloon angioplasty (CBA), balloon angioplasty (BA), or stenting for small vessel diseases. We studied a total of 327 lesions of small coronary disease treated either by CBA (n=87), BA (n=130), or stenting (n=110) in two affiliated institutes. A small coronary artery was defined as a reference vessel <2.5 mm using quantitative coronary angiography (QCA). Angiographic restenosis was encountered in 31% of the CBA, 46.5% of the BA, and 43.9% of the stent (p=0.048). Major adverse cardiac events (death, myocardial infarction, and target lesion revascularization) at follow-up were significantly lower in the CBA compared to other groups (CBA, 20.3%; BA, 37.3%; stent, 33.3%; p=0.036). The CBA procedure provided superior angiographic and clinical outcomes to the stenting or BA. The CBA may be a cost-effective and reasonable approach for the treatment of lesions in small coronary diseases.

A case of acute myocardial infarction treated with a new thrombectomy system.

Thrombotic occlusion in the culprit lesion of acute myocardial infarction was successfully recanalized using a 4.5 Fr thrombectomy catheter (RESCUE), which was also used to normalize the coronary blood flow. The retrieved specimens were white thrombi containing red thrombi and cholesterol crystals, indicating plaque rupture. Cathet Cardiovasc Intervent 2002;55:239–243.

A change in the pattern of vasospasm after stenting in a patient with vasospastic angina

We report an unusual case of a male patient with vasospastic angina in whom the pattern of coronary artery spasm changed after coronary stenting. The patient was admitted to our hospital with an acute coronary syndrome. Coronary angiography revealed an intermediate grade stenosis in the right coronary artery, and focal coronary spasm was provoked by intracoronary acetylcholine. A diagnosis of vasospastic angina was made, and the patient was followed medically. He subsequently was readmitted with refractory vasospastic angina and underwent coronary stenting. He was pain-free after stent implantation. Repeat angiography 6 months later showed no restenosis in the stented segment; however, coronary spasm was provoked in all areas except the stented segment by intracoronary acetylcholine injection.

Relationship between Insulin Levels and Coronary Atherosclerosis in Newly Diagnosed Diabetes Mellitus and Impaired Glucose Tolerance

Background: While some therapies implemented for newly diagnosed Diabetes Mellitus (DM) or impaired Glucose Tolerance (IGT) are effective in preventing cardiovascular events, investigations of coronary plaque in patients with newly diagnosed DM or IGT are lacking. Methods: We evaluated 96 patients with acute coronary syndrome. The External Elastic Membrane (EEM), Lumen Cross-Sectional Area (CSA), plaque CSA, and plaque burden in the Left Anterior Descending (LAD) artery proximal to the lesion, diagnosed as normal by Coronary Angiography (CAG), were measured using Intravascular Ultrasound (IVUS). Patients were divided according to DM status (DM=35, non-DM=61). Non-DM patients underwent a 75g Oral Glucose Tolerance Test (OGTT) and were further divided into abnormal glucose tolerance (AGT; n=29) and Normal Glucose Tolerance (NGT) groups (n=32). Results: Quantitative Coronary Angiography (QCA) showed no significant differences in EEM or vessel diameter between groups. However, the lumen CSA was significantly smaller in the DM group than in the NGT group. The plaque CSA and plaque burden were significantly greater in the DM and AGT groups than in the NGT group. Total insulin and glucose values and insulin and glucose values at 120 min after the OGTT correlated with plaque CSA; insulin values at 120 min after the OGTT showed the strongest correlation (R=0.505, P<0.01). Conclusions: Coronary plaque was identified among newly diagnosed DM or IGT patients even when the CAG appeared normal, suggesting that preventive measures against atherosclerosis should be initiated prior to DM development.

An example that presented giant aneurysm of the angina pectoris after percutaneous coronary intervention.

We present the case of a 70-year-old woman who was admitted to our hospital with heart failure due to a giant left ventricular aneurysm involving the apex and severe mitral regurgitation. Three months before the hospitalization, percutaneous coronary intervention was performed for severe stenosis of the left main trunk. During the procedure, there were no abnormalities of distal coronary flow due to problems like embolization, and repeat coronary angiography, performed after stabilization of heart failure, showed no new significant stenosis. We diagnosed her condition as a subepicardial aneurysm by pathological examination of the resected specimen.