Yoshihiro Iwasaki

Statistical analysis of clinical risk factors for coronary artery spasm: Identification of the most important determinant

Coronary artery spasm plays an important role in acute ischemic events, and it has a close relationship with coronary atherosclerosis. Thus we attempted to determine the most significant risk factor for coronary artery spasm. Among 3000 consecutive patients who underwent coronary cineangiography with ergonovine maleate testing, 330 with typical angina pectoris (group 1) and 294 with old myocardial infarction (group 2) were studied. We divided each group into three or four subgroups according to the presence of fixed organic stenosis (FOS+) or a positive reaction to ergonovine maleate (coronary artery spasm [CAS]+). We examined the relationship between coronary artery spasm and eight coronary risk factors: age, sex, hypertension, diabetes mellitus, smoking, and serum cholesterol, uric acid, and high-density lipoprotein cholesterol levels. The proportion of smokers in the subgroups with CAS(+) was significantly higher than in the subgroups with CAS(-)(p less than 0.01). There was no correlation between smoking and fixed organic stenosis. According to the results of multiple regression analysis, there was a positive correlation between smoking and CAS(+) and between serum high-density lipoprotein cholesterol levels and CAS(+)(p less than 0.01). Thus we concluded that smoking is the most significant risk factor in discriminating between patients with and without coronary artery spasm.

Serial angiographic follow-up after successful direct angioplasty for acute myocardial infarction

This serial follow-up study was designed to identify the time course of reocclusion and/or restenosis after direct angioplasty for acute myocardial infarction. Direct angioplasty for acute myocardial infarction was attempted in 160 patients. Of the 141 patients who underwent successful reperfusion and were discharged, 137 (97%) were enrolled in this study. At the 3-week follow-up study (100% eligible), angiographic restenosis of the infarct-related artery was documented in 21 patients (16%), 9 (43%) of which were reocclusions. At 4 months in 100 patients (92% of those eligible), restenosis was newly documented in 28 infarct-related arteries (28%), 3 of which were reocclusions (11%). At 1 year in 64 patient (89% of those eligible), restenosis was newly documented in 5 infarct-related arteries (7.8%), with no reocclusions. The cumulative restenosis rate was 20% at 3 weeks, 43% at 4 months, and 47% at 1 year; when divided into occlusive and nonocclusive types, restenosis rates were 12% and 8.8% at 3 weeks and 14% and 29% at 4 months, respectively. Restenosis was most prevalent within the first 4 months and rarely occurred after that. When restenosis is manifested as reocclusion, it occurs earlier than in nonocclusive restenosis, often within 3 weeks.

Balloon rupture during coronary angioplasty causing dissection and intramural hematoma of the coronary artery; a case report

A 73-year-old male with diabetes mellitus was referred for coronary angiography (CAG). He presented with stable effort angina pectoris. CAG showed a significant stenotic lesion in the proximal-segment of the left anterior descending (LAD) coronary artery with heavy calcification. He then underwent angioplasty for the LAD stenosis. On the second balloon dilatation, the balloon was inflated to 22xa0atm, at which point the balloon waist had not yet yielded and balloon rupture occurred. Immediately after the procedure, CAG showed no-reflow phenomena and chest pain occurred. Intravascular ultrasound (IVUS) imaging revealed a dissection into the media with extension into the medial space without reentry, and demonstrated significant stenosis and obstruction of the distal LAD with a semilunar echo-dense intramural hematoma. To bail out, two bare metal stents were deployed. After the procedure, proper stents expansion and no residual dissection flap were detected either by IVUS or CAG. The final CAG showed a good result with TIMI-3 coronary flow. This case highlights balloon rupture during coronary angioplasty with heavy calcification caused no-reflow phenomena by dissection and intramural hematoma of the coronary artery. We could bail out hematoma by coronary stent implantation with complete cover of the coronary dissection.

Clinical usefulness of the Driver® stent in a retrospective, collaborative, multicenter, open-label study in Japanese real-world patients with coronary artery disease and the drug-eluting stent era

The objectives of the present study were to determine predictors for target lesion revascularization (TLR) and to examine the clinical usefulness of the Driver® stent (a cobalt alloy, modular-type) in Japanese patients with coronary artery disease. Data on 631 Japanese patients including 241 with stable angina and 361 with acute coronary syndrome—who had been implanted with the Driver® stent (805 lesions) between August 2004 and February 2005—were collected retrospectively; 95.0 and 81.7% of these lesions were de novo and ACC/AHA classification B2/C type, respectively. Early angiography of 622 patients revealed 1) the preprocedural minimal lumen diameter (MLD) of 0.80xa0±xa00.51xa0mm, with lesion lengths of 17.1xa0±xa07.3xa0mm, and 2) the postprocedural MLD of 2.95xa0±xa00.55xa0mm, with MLD gains of 2.14xa0±xa00.68xa0mm. At 270xa0days of clinical follow-up, the incidences of major adverse cardiac events (MACE), TLR, and early stent thrombosis (ST) were 18.8, 14.7, and 0.2%, respectively; the TLR rate decreased statistically significantly to 5.3 and 5.9% when implanting the Driver® stent (3.5 and 4.0xa0mm) and by IVUS, respectively. Absence rate of diabetes mellitus, presence rate of AMI, presence rate of stent diameters of ≥3.5xa0mm, and presence rate of IVUS-guided PCI showed lower TLR rates, with statistically significant differences. Uni- and multivariate analyses revealed that AMI and stent diameter (≥3.5xa0mm) are significant predictors for TLR (0.048 and 0.047, respectively), indicating that physicians are recommended to consider these variables when selecting candidate real-world patients for IVUS-guided PCI.