小林 欣夫

Intravascular ultrasound (IVUS) evaluation was performed in 33 lesions with sirolimus-eluting stent (SES) failure: 4 thromboses; 26 in-stent restenoses (including 6 edge stenoses), 4 new stenoses >5 mm proximal to the stent, and 1 patient with no evidence of the implanted SES (presumably because of embolization): A minimum stent area <5.0 mm(2) (stent underexpansion) was observed in 67% of all SES failures (in particular, 67% of intrastent restenosis); negative remodeling was observed in 4 of 6 stent edge restenoses, and new lesions were secondary to an increase in plaque area. (C) 2005 by Excerpta Medica Inc.

Background - Little is known about causes of intimal hyperplasia (IH) after sirolimus-eluting stent (SES) implantation. Methods and Results - Intravascular ultrasound was performed in 24 lesions with intra-SES restenosis and a comparison group of 25 nonrestenotic SESs. To assess stent strut distribution, the maximum interstrut angle was measured with a protractor centered on the stent, and the visible struts were counted and normalized for the number of stent cells. In SES restenosis patients, minimum lumen site was compared with image slices 2.5, 5.0, 7.5, and 10.0 mm proximal and distal to this site. The minimum lumen site had a smaller IVUS lumen area at follow-up (2.7 +/- 0.9 versus 6.2 +/- 1.9 mm(2); P < 0.01), larger maximum interstrut angle ( 135 +/- 39° versus 72 +/- 23°; P < 0.01), larger IH area (3.4 +/- 1.5 versus 0.6 +/- 1.1 mm(2); P < 0.01) and thickness (0.7 +/- 0.3 versus 0.1 +/- 0.2 mm; P < 0.01) at maximum interstrut angle, and fewer stent struts (4.9 +/- 1.0 versus 6.0 +/- 0.5; P < 0.01) even when normalized for the number of stent cells (0.78 +/- 0.15 versus 0.97 +/- 0.07; P < 0.01). Compared with nonrestenotic SES, the restenosis lesions also had a smaller minimal lumen area, larger IH area, thicker IH at maximum interstrut angle, fewer stent struts, and larger maximum interstrut angle. Multivariate analysis identified the number of visualized stent struts normalized for the number of stent cells and maximum interstrut angle as the only independent IVUS predictor of IH cross-sectional area ( P < 0.01 and P < 0.01), minimum lumen area ( P < 0.01 and P < 0.01), and IH thickness ( P < 0.01 and P < 0.01). Conclusions - The number and distribution of stent struts affect the amount of neointima after SES implantation.

Coronary remodeling and plaque composition were compared between focal and diffuse coronary lesions. Negative remodeling and fibrous and calcified plaque compositions contribute to stenosis development in diffuse lesions more frequently than in focal lesions. (C)2004 by Excerpta Medica, Inc.

The treatment of in-stent restenosis using balloon angioplasty alone often produces excellent early results, but is associated with high rate of recurrence. Previous studies have demonstrated significant tissue reintrusion shortly after the treatment of in-stent restenosis with balloon angioplasty. The study was designed to elucidate the contribution of early lumen loss 6 hr after balloon angioplasty to lumen loss at follow-up. We prospectively performed quantitative coronary angiography and intravascular ultrasound in 12 patients with in-stent restenosis before intervention, after the final procedure, 6 hr later (5.6 +/- 1.4 hr), and at follow-up (7.7 +/- 2.3 months). Compared with immediately after balloon angioplasty, by 6 hr postintervention, the minimum lumen diameter (MLD) and lumen cross-sectional area had decreased significantly (2.48 +/- 0.44 to 2.01 +/- 0.57 mm, P = 0.01, and 7.0 +/- 1.2 to 5.5 +/- 1.4 mm(2), p = 0.004, respectively). Furthermore, the MILD decreased further between 6 hr postintervention and long-term follow-up (2.01 +/- 0.57 to 1.55 +/- 0.64 mm; P = 0.001). Patients who showed recurrence of restenosis at follow-up had greater early lumen loss than patients without recurrence of restenosis (0.71 +/- 0.31 vs. 0.23 +/- 0.13 mm; P = 0.006). Diffuse lesions had greater early lumen loss compared to focal lesions (0.75 +/- 0.35 vs. 0.28 +/- 0.13 mm; P = 0.008). Early lumen loss is common after the treatment of in-stent restenosis by balloon angioplasty. Within the first 6 hr postintervention, 32% +/- 29% of acute lumen gain is lost, and early lumen loss contributed to 42% +/- 18% of total lumen loss at follow-up. (C) 2004 Wiley-Liss, Inc.

Background In a previous study the adjusted thresholds at which the diameters of coronary arteries determined by enhanced electron-beam computed tomography (CT) scans are equal to the corresponding quantitative coronary angiography measurements were analyzed, and their correlation with maximum CT values for the vessel short axes was determined. A rapid accurate method for such measurements was sought by substituting maximum CT values for the descending aorta in the corresponding axial images for those for the short axes. Methods and Results In 8 patients, 179 sites were measured. Means (+/-SD) of adjusted thresholds and the maximum CT values for vessel short axes and the descending aorta in the corresponding axial images for all vessels were 108+/-66, 227+/-80, and 363+/-75 Hounsfield Unit (HU), respectively. Adjusted thresholds correlated with the maximum CT values for the corresponding vessel short axes and the descending aorta in the corresponding axial images, with R-2=0.55, 0.33, p<0.01, respectively. An abbreviated formula for use of maximum CT values for the descending aorta in the corresponding axial images was y=0.5x-75 (HU) (y = adjusted threshold, x = maximum CT value for the descending aorta in the corresponding axial image). Conclusions The abbreviated formula provided a rapid, accurate method for measurements independent of arterial enhancement.

This case report demonstrates subacute luminal narrowing 20 days after balloon angioplasty in the left anterior descending coronary artery due to an intramural hematoma. Stenting was performed and resulted in side-branch compromise caused by squeezing the hematoma from the left anterior descending coronary artery into the left circumflex artery. Another stent was deployed to treat the stenosis in the left circumflex artery. (C) 2004 Wiley-Liss, Inc.

Larger final lumen dimensions after percutaneous coronary interventions in native coronary arteries lead to lower restenosis rates. We sought to determine the impact of stent expansion, as assessed by intravascular ultrasound, on clinical results of stent implantation in saphenous vein grafts (SVGs). We identified 226 consecutive patients who underwent intravascular ultrasound-guided stenting of 234 de novo SVG lesions. Patients were divided into 2 groups based on the final stent cross-sectional area (CSA): group I (stent CSA <100% of the reference lumen CSA, n = 176 patients, 182 lesions) and group II (stent CSA greater than or equal to100% of the reference lumen CSA, In = 50 patients, 52 lesions). Baseline patient characteristics were similar between the 2 groups with the exception of smaller lesions in group II. More aggressive stent expansion (group 11) was associated with (1) increased rates of in-hospital non-Q-wave myocardial infarction (29% vs 17%, p = 0.05), (2) any myocardial infarction (26% vs 8%, p = 0.003) at 1-year follow-up, and (3) no improvement in target vessel revascularization at 1 year (31% vs; 26%, p = 0.3). Aggressive stent expansion in SVG lesions resulted in higher myocardial infarction rates and, unlike native arteries, no improvement in target vessel revascularization rate at 1 year. A less aggressive stent implantation strategy in SVGs than in native coronary lesions appears prudent. (C) 2004 by Excerpta Medica, Inc.

OBJECTIVES The present study evaluated clinical outcomes in diabetic patients after multivessel stenting. BACKGROUND Multivessel angioplasty studies have reported decreased survival in diabetic patients undergoing conventional balloon angioplasty compared with coronary artery bypass graft surgery (CABG). However, several studies have demonstrated excellent procedural success and acceptable clinical outcomes after multivessel stenting. METHODS Multivessel stenting was performed in 689 patients with 1,639 native coronary lesions. Patients were classified into three groups according to diabetes mellitus (DM) status: 1) no DM (501 patients/1,200 lesions); 2) DM treated with oral agents (102 patients/235 lesions); and 3) DM treated with insulin (86 patients/204 lesions). RESULTS Procedural success was high overall. In-hospital CABG was higher in diabetics treated with insulin compared with the other two groups (3.5% vs. 0.4% vs. 1.0%, p = 0.02). There were no significant differences in the incidence of in-hospital cardiac death and myocardial infarction. Diabetic patients treated with oral agents or insulin had higher one-year target lesion revascularization rates than non-diabetic patients (25% vs. 35% vs. 16%, p < 0.001). Lower one-year survival was observed in diabetic patients treated with either oral agents or insulin, compared with non-diabetic patients (85% vs. 86% vs. 95%, p < 0.001). On multivariable analysis, DM was an independent predictor of one-year mortality, myocardial infarction, and target lesion revascularization after multivessel stenting. CONCLUSIONS Despite a high technical success rate of multivessel stenting, diabetic patients, especially those treated with insulin, have higher in-hospital CABG, higher subsequent revascularization rates, and lower one-year survival than non-diabetic patients. (C) 2004 by the American College of Cardiology Foundation

Background - We used intravascular ultrasound (IVUS) to evaluate recurrence after sirolimus-eluting stent (SES) implantation treatment of in-stent restenosis (ISR). Methods and Results - Forty-eight ISR lesions ( 41 patients with objective evidence of ischemia) were treated with SES. Recurrent ISR was identified in 11 lesions ( all focal); repeat revascularization was performed in 10. These were compared with 16 patients ( 19 lesions) without recurrence as documented by angiography. Nine of 11 recurrent lesions had a minimum stent area (MSA) < 5.0 mm(2) versus 5 of 19 nonrecurrent lesions ( P = 0.003); 7 of 11 recurrent lesions had an MSA < 4.0 mm(2) versus 4 of 19 nonrecurrent lesions (P = 0.02); and 4 of 11 recurrent lesions had an MSA < 3.0 mm(2) versus 1 of 19 nonrecurrent lesions ( P = 0.03). A gap between SESs was identified in 3 of 11 recurrences versus 1 of 19 nonrecurrent lesions. Conclusions - Stent underexpansion is a significant cause of failure after SES implantation treatment of ISR.

Background Various autopsy and intravascular ultrasound (IVUS) studies have shown neointimal proliferation as the main mechanism of in-stent restenosis (ISR) responsible for >95% of luminal narrowing-while stent struts are not compressed. ISR of diffuse type has a high incidence of recurrence (up to 70%) after balloon angioplasty (PTCA). Tissue ablation with percutaneous rotational coronary atherectomy (PRCA) may be more efficacious compared to tissue compression or extrusion after PTCA for the interventional treatment of diffuse ISR. Methods The Rotational. Atherectomy Versus Balloon Angioplasty for Diffuse In-Stent Restenosis (ROSTER) trial is a single-center, randomized trial comparing PRCA to PTCA (both with IVUS guidance) in the treatment of diffuse ISR in 200 patients. In the PRCA group (n = 100), rotablation was performed using a burr-to-artery ratio >0.7 followed by adjunctive balloon dilatation at low pressure (4-6 atm). In the PTCA group (n = 100), high-pressure (> 12 atm) balloon dilatation was performed using an optimal size balloon. The study's primary end point was target lesion revascularization (TLR) at 9 months and secondary end points included clinical events at 1 year and angiographic restenosis in a substudy of the last 75 patients enrolled. Results Baseline clinical and angiographic variables were comparable between the 2 groups with similar procedural and angiographic success, but a higher rate of repeat stenting occurred in the PTCA group (31% vs 10%; P <.001). Although the angiographic acute luminal gain was similar between the 2 groups, IVUS analysis revealed lower residual intimal hyperplasia area after PRCA versus PTCA (2.1 ± 0.9 mm(2) vs. 3.3 ± 1.8 mm(2); P = .005). At a mean follow-up of 12 ± 2 months, there were 2 deaths, 3 myocardial infarctions, and 3 coronary artery bypass graft procedures in each group. TLR incidence was 32% in the PRCA group and 45% in the PTCA group (P = .042), with a similar trend noted in the angiographic substudy. Conclusion The ROSTER trial for diffuse ISR revealed both PRCA and PTCA to be safe and effective, but PRCA resulted in less residual intimal hyperplasia, lower repeat stent use, and decreased TLR.

Even in the drug-eluting stent era, percutaneous coronary intervention in bifurcation lesions is complex and technically demanding, and considerable expertise is required. This case report describes in-stent restenosis due to stent underexpansion after kissing stents using sirolimus-eluting stents. (C) 2003 Wiley-Liss, Inc.

OBJECTIVES We sought to determine the impact of aggressive stent expansion on creatine kinase-MB isoenzyme (CK-MB) release and clinical restenosis. BACKGROUND Elevation of CK-MB after percutaneous coronary interventions has been associated with late mortality. METHODS We identified 989 consecutive patients who underwent intravascular ultrasound-guided stenting of 1,015 coronary lesions. Patients were divided into three groups according to stent expansion, defined as the ratio of final lumen over the reference lumen cross-sectional areas: Group 1 (ratio <70%, n = 117 patients with 126 lesions); Group 2 (ratio 70% to 100%, n = 551 patients with 562 lesions); Group 3 (ratio >100%, n = 321 patients with 327 lesions). RESULTS The peak CK-MB values increased significantly with increasing stent expansion: CK-MB = 3 to 5 X normal occurred 16%, 18%, and 25% in Groups 1, 2, and 3, respectively, p = 0.02; CK-MB >5 times normal occurred 9%, 13%, and 16% respectively, p = 0.02. Conversely, at one year follow-up there was a stepwise decrease in target lesion revascularization (11% vs. 19% and 17%, respectively, p = 0.04) and major adverse cardiac events with increasing stent expansion. In addition, there was a trend toward lower mortality in Group 3 (9% vs. 4.4% vs. 4.0%, p = 0.07). CONCLUSIONS Intravascular ultrasound-guided stent overexpansion (final lumen greater than reference lumen cross-sectional area) is accompanied by a higher periprocedural CK-MB release but a lower target lesion revascularization and a trend toward lower mortality. at one year. Increased periprocedural CK-MB release appears as a trade-off for optimal stent implantation and lower clinical restenosis. (C) 2003 by the American College of Cardiology Foundation

Despite similar early clinical events, patients who undergo treatment of small vessels are at an increased risk for target lesion revascularization (TLR) after coronary artery stenting. We sought to determine predictors of TLR after stent implantation in small coronary arteries. We identified 423 consecutive patients who underwent intravascular ultrasound (IVUS)-guided small vessel stenting procedures in 465 coronary lesions with an angiographic reference vessel diameter of <2.75 mm. Patients were divided into 2 groups based on a final IVUS lumen area of less than or equal to6.0 mm(2) (n = 345 lesions, group I) and >6.0 mm(2) (n = 115, group II). Baseline patient characteristics and in-hospital outcomes were similar between the 2 groups, except for a higher rate of restenotic lesions in group I and bifurcation lesions in group II. Group I had higher TLR rates at 1 year compared with group II patients (39% vs 26%, p = 0.02). The TLR rate appeared to decrease with greater stent expansion, especially at >90% of the reference vessel area, as assessed by IVUS. By multivariate analysis, an IVUS final stent area of less than or equal to6 mm(2), diabetes, absence of prior myocardial infarction, and history of intervention were independent predictors of 1-year TLR in this population. Final stent area of >6.0 mm(2) and greater stent expansion were associated with a decrease in TLR. Therefore, there does not appear to be any "downside" to aggressive stent implantation strategies in small vessels. In contrast, IVUS allows maximization of final lumen dimensions to minimize clinical restenosis. (C)2003 by Excerpta Medica, Inc.

Background-It is not clear why some plaque ruptures lead to acute coronary syndromes (ACS) but others do not. Methods and Results-We analyzed 80 plaque ruptures in 74 patients and compared culprit lesions of ACS patients with nonculprit lesions of ACS patients and lesions of non-ACS patients; both culprit and nonculprit plaque ruptures were studied in 6 of 54 ACS patients. Intravascular ultrasound findings suggesting thrombus were observed more frequently in culprit lesions of ACS patients (n=35) compared with nonculprit lesions of ACS patients (n=19) and lesions of non-ACS patients (n=26): 60% versus 32% versus 8% (P<0.001). At the minimal lumen site, smaller lumen areas (3.3±1.5 versus 5.4±2.6 versus 6.1±2.0 mm(2), P<0.001) and greater area stenosis (61+/-15% versus 50+/-14% versus 46+/-18%, P=0.002) and plaque burden (80+/-8% versus 71+/-8% versus 69+/-10%, P<0.001) were observed in culprit lesions of ACS patients compared with nonculprit lesions of ACS patients and lesions of non-ACS patients. Lesions were longer (18.7±6.4 versus 154.9±6.1 versus 12.0±4.9 mm, P<0.001) and rupture site remodeling indices were greater (1.26+/-0.21 versus 1.24+/-0.21 versus 1.09+/-0.05, P=0.002). Independent predictors of culprit plaque ruptures in ACS patients were smaller minimum lumen areas (P=0.02) and presence of thrombus (P=0.01). Conclusions-Ruptured plaques in culprit lesions of ACS patients have smaller lumens; greater plaque burdens, area stenosis, and remodeling indices; and more thrombus. Plaque rupture itself does not lead to symptoms. The association of plaque rupture with a smaller lumen area and/or thrombus formation causes lumen compromise and leads to symptoms.

The present study evaluated in-hospital and 1-year outcomes after multivessel stenting in patients aged greater than or equal to80 (75 patients, 241 lesions) and <80 years (894 patients, 2,678 lesions). Despite a high technical success rate of multivessel stenting, octogenarians had higher in-hospital cardiac and noncardiac complication rates and a higher mortality rate at 1-year clinical follow-up compared with their younger counterparts. (C)2003 by Excerpta Medica, Inc.

Percutaneous coronary intervention (PCI) devices are much more expensive in Japan than in the United States, but their prices were reduced in April 2002. This study evaluated the impact of that change in the price of PCI devices on medical expenses. In-hospital costs of 22 consecutive patients who underwent elective single-vessel PCI without a debulking procedure before April 2002 were collected and the in-hospital cost of each patient was recalculated by applying the current prices of the PCI devices and those in the USA. For patients treated with PCI before April 2002, the in-hospital cost was Y1,456,375+/-358,781, but when the current price is used, the in-hospital cost is estimated to be Y1,355,812+/-313,237 (7% reduction). If the prices of the devices were reduced to those in USA, there would be a 53% reduction (Y689,417+/-99,139). Although the change in the price of PCI devices in April 2002 has reduced in-hospital costs, the devices are still much more expensive in Japan than in the USA. Further reduction of the price is required to make PCI more cost-effective.

Negative remodeling is commonly observed in stenotic coronary lesions. It is unknown whether negative remodeling is an early or late event. This study was designed to elucidate when negative remodeling occurs in the development of coronary stenosis. Remodeling was assessed by preintervention intravascular ultrasound in 104 native coronary lesions with intermediate stenosis (20% to 60% of diameter stenosis measured by quantitative coronary angiography). Positive remodeling was defined as lesion external elastic membrane (EEM) cross-sectional area (CSA) greater than the proximal reference, intermediate remodeling as lesion EEM CSA between those of the proximal and distal references, and negative remodeling as lesion EEM CSA less than the distal reference. Positive, intermediate, and negative remodeling were observed in 18%, 32%, and 50%, respectively, of lesions with intermediate stenosis. Lesions with negative and intermediate remodeling had more hard plaque compared with those with positive remodeling (79% vs 70% vs 42%, p = 0.02). Calcium was more frequent in lesions with negative and intermediate remodeling than in those with positive remodeling (52% vs 55% vs 16%, p = 0.01). Lesions with negative remodeling had smaller EEM CSA (11.5 +/- 5.2 2 vs. 13.7 +/- 3.4 vs 14.5 +/- 5.6 mm, p = 0.03) and less plaque (7.9 +/- 4.6 vs 10.8 +/- 3.4 vs 10.8 +/- 4.9 mm(2), p = 0.004) compared with positive and intermediate re-modeling lesions, although lumen CSA (3.7 +/- 1.7 vs 2.8 +/- 0.8 vs 3.6 +/- 1.3 mm(2), P = 0.1) and area stenosis (57 +/- 15% vs 59 +/- 14% vs 56 +/- 10%, p = 0.7) were similar. Negative remodeling is frequently observed in lesions with intermediate stenosis. This suggests that negative remodeling occurs early in lesion formation. (C) 2003 by Excerpta Medica, Inc.

Transforming growth factor-beta (TGF-beta) has been implicated in the development of diabetic glomerulopathy. In order to evaluate a role of Smad3, one of the major signaling molecules downstream of TGF-beta, in the pathogenesis of diabetic glomerulopathy, Smad3-null mice were made diabetic with streptozotocin injection and analyzed 4 weeks after induction of diabetes. Electron microscopy revealed that the thickness of glomerular basement membrane (GBM) in wild-type diabetic mice was significantly higher than that in non-diabetic mice, whereas no appreciable GBM thickening was found in Smad3-null diabetic mice. Urinary albumin excretion was dramatically increased in wild-type diabetic mice, whereas Smad3-null diabetic mice did not show any overt albuminuria. Northern blotting revealed that mRNA levels of fibronectin and alpha 3 chain of type IV collagen (alpha 3Col4) in renal cortex of wild-type diabetic mice were approximately twice as much as those of non-diabetic mice, whereas their mRNA levels were not increased in Smad3-null diabetic mice. Real-time polymerase chain reaction (PCR) also confirmed diabetes-induced upregulation of fibronectin and alpha 3Col4 in glomeruli of wild-type mice. Glomerular expression of TGF-beta 1, as assessed by real-time PCR, was enhanced to a similar degree in wild-type and smad3-null diabetic mice, indicating that the observed differences between wild-type and Smad3-null mice are not attributable to difference in the expression of TGF-beta 1. These data clearly demonstrate a critical role of Smad3 in the early phase of diabetic glomerulopathy. This may be due at least partly to the present findings that diabetes-induced upregulation of fibronectin and alpha 3Col4 is dependent on Smad3 function.

Correlations between baseline hemodynamic and oximetric variables during an invasive exercise test and an improvement in peak oxygen uptake (peak (V) over circle o2) after exercise training (ET) were examined in 20 patients who participated in a cardiac rehabilitation program after acute myocardial infarction (AMI). Peak (V) over circle o2 significantly increased by 23+/-21% (p<0.01) after ET and the improvement best correlated with the change in O-2 extraction fraction ([arterial O-2 content-venous O-2 content] /arterial O-2 content) during an exercise test before ET (r=-0.61, p<0.01). Exercise capacity was improved to a greater extent by ET in patients with a smaller increase in O-2 extraction fraction during an exercise test before ET. Thus, O-2 extraction fraction during an exercise test before ET may be a useful predictor of the improvement in exercise capacity after ET in post-AMI patients.

Angiographic criteria to select patients for optimal balloon angioplasty.

The present study evaluated the effect of stent overdilatation on lumen size and intimal hyperplasia at follow-up. Stent overdilatation results in larger follow-up lumens despite larger late lumen loss due to greater intimal hyperplasia.

Although previous randomized trials 1-2 have demonstrated lower restenosis rates in selected lesions with coronary stents than with conventional balloon angioplasty. in-stent restenosis remains an important clinical problem.(3,4) Previous serial angiographic studies(5,6) showed that lumen loss after stenting occurred within 6 months. On the other hand, improvements in lumen dimensions between 6 months and 2 to 3 years have been demonstrated by angiography.(6-9) Serial (postintervention and at 6-month follow-up) intravascular ultrasound (IVUS) studies(10,11) have demonstrated that coronary stenting eliminates negative arterial remodeling, and thus intimal hyperplasia is solely responsible for in-stent restenosis. However, little has been reported about changes in intimal hyperplasia that occur beyond this 6-month period. This serial IVUS study evaluated the changes in intimal hyperplasia between 6 and 12 months after stent placement.

We identified 1,215 patients (322 women, 26.5%) who received glycoprotein (GP) IIb/IIIa inhibitors during 1,852 coronary artery stenting procedures. Compared with men, women had similar rates of in-hospital ischemic events and vascular complications, and similar 1-month major adverse cardiac events rates. Therefore. use of the GP Ilb/IIIa inhibitors appears to eliminate the previously noted "disadvantages" in women with respect to early clinical outcome after interventional procedures.

Objectives The purpose of this study, was to evaluate the approach of intravascular ultrasound (IVUS)-guided percutaneous transluminal coronary, angioplasty (PTCA) with spot stenting (SS) for the treatment of long coronary, lesions. Background Treating long coronary lesions with balloon angioplasty, results in suboptimal short- and long-term outcomes. Full lesion coverage with traditional stenting (TS) has been associated with a high restenosis rate. Methods We prospectively evaluated a consecutive series of 130 long lesions (>15 mm) in 101 patients treated with IVUS-guided PTCA and SS. The results were compared with those of TS int a matched group of patients. Coronary angioplasty was performed with a balloon to vessel ratio of 1:1, according to the IVUS media-to-media diameter of the vessel at the lesion site, to achieve prespecified IVUS criteria: lumen cross-sectional area (CSA) greater than or equal to5.5 mm(2) or greater than or equal to 50% of the vessel CSA at the lesion site. The stents were implanted only, in the vessel segment where the criteria were not met. Results In the SS group, stents were implanted in 67 of 130 lesions, and the mean stent length was shorter than that of lesions in the matched TS group (10.4 +/- 13 mm vs. 32.4 +/- 13 mm, p<0.005). The 30-day major adverse cardiac event (MACE) rate was similar (5%) for both groups. Angiographic restenosis was 25% with IVUS-guided SS, as compared with 39% in the TS group (p<0.05). Follow-up MACE and target lesion revascularization rates were lower in the SS group than in the TS group (22% vs. 38% [p<0.05] and 19% vs. 34% [p<0.05], respectively). Conclusions Intravascular ultrasound-guided SS for the treatment of long coronary, lesions is associated with good acute outcome. Angiographic restenosis and follow-up MACE rates were significantly lower than those with TS. (J Am Coll Cardiol 2001;38:1427-33) (C) 2001 by the American College of Cardiology.

We report five cases treated with brachytherapy through the internal mammary artery (IMA) for in-stent restenosis at the distal anastomosis (n = 3) and in the left anterior descending coronary artery beyond the distal anastomosis (n = 2). After angioplasty, catheter-based gamma radiation was performed. There was no delivery failure of the radiation system. All cases had angiographic success and no procedural or in-hospital complications. (C) 2001 Wiley-Liss, Inc.

In 382 de novo lesions in native coronary arteries, clinical and angiographic predictors of a large discrepancy in vessel diameter between intravascular ultrasound and quantitative angiography were evaluated. The discrepancy was highest in diabetics, in vessels <3.0 mm on angiography, and in the proximal segments of the coronary tree.

We report treatment of a lesion with coronary stent underexpansion due to heavily calcified plaque. Conventional balloon angioplasty was attempted for in-stent restenosis, but the lesion was undilatable despite 25-atm inflation pressure. Intravascular ultrasound (IVUS) revealed stent underexpansion due to heavily calcified plaque. Rotational atherectomy was performed using a stepped burr approach, after which repeat IVUS revealed marked ablation of the stent-calcium complex. Adjunctive balloon angioplasty then easily resulted in full balloon and stent expansion, with an excellent angiographic and IVUS result. The patient's hospital course was uneventful. Cathet Cardiovasc Intervent 2001; 52:208-211. (C) 2001 Wiley-Liss, Inc.

Background: It is known that left ventricular systolic function at rest does not correlate well with exercise capacity of patients with heart failure. However, the contribution of left ventricular diastolic dysfunction, especially during exercise, to exercise capacity of cardiac patients remains to be determined. Objective: To determine the impact of left ventricular systolic and diastolic function during exercise on exercise capacity of patients with left ventricular dysfunction after myocardial infarction. Methods: A symptom-limited exercise test was performed with measurements for hemodynamics and uptake of oxygen (VO2) of 26 men who had previously suffered myocardial infarction. These patients were divided into two groups according to their peak VO2 (group 1 with peak VO2 ≥ 16ml/kg per min, n= 13 and group 2 with peak VO2 &lt 16 ml/kg per min, n= 13). Pulmonary arterial pressure, left ventricular and systemic arterial pressure, and cardiac output were measured at rest and during exercise. Results: At rest, there was no difference between the two groups in terms of hemodynamic parameters except for minimal dP/dt, minimal left ventricular pressure (LVP) and time constant for decay of left ventricular pressure (τ). During peak exercise, cardiac output, left ventricular end-diastolic pressure (EDP), minimal dP/dt, minimal LVP, and τ for the two groups were significantly different. Furthermore, peak VO2O2 was significantly correlated with τ, minimal LVP, minimal dP/dt, EDP, and maximal dP/dt during peak exercise for the whole group of patients. Conclusion: Left ventricular diastolic function during exercise, i.e. diastolic reserve, may be an important determinant of exercise capacity of patients with left ventricular dysfunction after myocardial infarction. © 2001 Lippincott Williams &amp Wilkins.

A 64-year-old male with unstable angina underwent direct stenting in the proximal and mid-left anterior descending coronary artery (LAD) lesions. Although coronary angiography showed a good result, intravascular ultrasound imaging revealed a dissection flap protruding through the struts of the stent in the proximal LAD. Another stent was deployed in the first stent (stent-in-stent) to seal it. The patient's in-hospital course was uneventful. Subacute stent thrombosis was not observed.

Background-The aim of this study was to use serial volumetric intravascular ultrasound to evaluate the effect of gamma -radiation on recurrent in-stent restenosis. Methods and Results-After successful reintervention, patients were randomized to receive either Ir-192 Or placebo. Intravascular ultrasound studies with motorized pullback (0.5 mm/s) were performed immediately after irradiation and at 8-month follow-up in 70 patients. Paired volumetric analysis of the stented segment and of 5-mm proximal and distal reference segments was performed; this included measurements of the external elastic membrane, lumen, plaque and media (external elastic membrane minus lumen), stent, and intimal hyperplasia (stent minus lumen). Baseline proximal reference, stent, and distal reference measurements were similar in both groups. The changes in proximal and distal reference measurements of the external elastic membrane, plaque and media, and lumen areas were similar in both groups. However, the decrease in stented segment lumen volume was less in the Ir-192 patients than the placebo patients (-25+/-34 mm(3) versus -48+/-42 mm(3); P=0.0225), and the increase in the volume of intimal hyperplasia in the stented segment was less in the Ir-192 patients than in the placebo patients (28+/-37 mm(3) versus 50+/-40 mm(3); P=0.0352). When averaged over the length of the stented segment (32+/-13 mm versus 33+/-14 mm; P=0.9), the increase in mean area of intimal hyperplasia was 0.8+/-1.0 mm(2) in the Ir-192 group and 1.6+/-1.2 mm(2) in the control group (P=0.0065). Late stent-vessel wall malapposition was noted in one placebo patient and no Ir-192 patients. Conclusions-gamma -Radiation therapy can effectively prevent recurrent in-stent restenosis by inhibiting neointimal formation within the stent. At the stent edge, there were no significant differences between Ir-192 and placebo patients.

We report a new stenting technique employed in 10 patients to treat lesions immediately proximal to a bifurcation (pseudobifurcation). A stent is mounted on two balloon catheters and advanced into the lesion immediately proximal to the bifurcation until the distal portion of the balloon catheters enters each branch at the bifurcation. This is followed by kissing balloon inflation for stent deployment. In all 10 cases, the final angiogram showed a good result at the lesion site and no ostial compromise of any of the branches. Cathet. Cardiovasc. Intervent. 51:347-351, 2000. (C) 2000 Wiley-Liss, Inc.

The present study evaluated the cost of coronary stenting compared with conventional balloon angioplasty in Japan. Procedural cost was estimated as the sum of the procedural fee and the cost of devices such as angioplasty balloon and stent. The data such as the number of balloon catheters and stents used, and the rate of crossovers that was shown by the Stent Restenosis Study (STRESS) were applied to calculate the costs of stenting and conventional balloon angioplasty. For the estimation of hospital room and nursing costs, the length of the in-hospital stay was estimated at 7 days. The costs of procedures such as laboratory and radiological tests were determined based on routine coronary intervention at Chiba University Hospital. The rates of target lesion revascularization in the STRESS trial (conventional balloon angioplasty: 21%, stenting: 15%) were used to calculate the cost during follow up. The in-hospital costs of conventional balloon angioplasty and stenting were estimated to be Yen 982,300 and Yen 1,416,893, respectively. The overall costs, including follow-up cost, of conventional balloon angioplasty and stenting were estimated to be Yen 1,188,583 and Yen 1,564,238, respectively. The in-hospital cost of stenting is higher compared with conventional balloon angioplasty because of greater balloon use and direct stent cost. Lower target lesion revascularization reduces the cost difference between conventional balloon angioplasty and stenting, but the higher initial cost of stenting is not fully offset.

A 65-year-old male with unstable angina underwent coronary angiography, which revealed a significant stenotic lesion in the right coronary artery. This narrowing was subsequently treated with the Multi-Link stent. During the balloon inflation associated with stent deployment, balloon rupture occurred and resulted in overdilatation of an elastic membrane in the stent delivery system. This, in turn, resulted in coronary dissection, which required treatment with further stenting.

After placing a stent in the main vessel of a bifurcation lesion, it is often necessary to perform further balloon inflation or stent placement through the stent struts in order to treat a lesion of the secondary vessel or side branch. This balloon inflation with dilatation through the cells of the stent in the main vessel results in stent strut disfigurement. This disfigurement causes various degrees of stenosis within the main vessel secondary to stent strut deformity. The degree of strut deformity, and therefore stenosis, may vary significantly depending on stent design and structure. A model of a bifurcation lesion with an angle of 45°was created from acrylic resin. The diameters of the main vessel and the secondary vessel were both 3.5 mm. Deployment of the Palmaz-Schatz stent (PS, n = 5), NIR stent (n = 5), or Multi-Link stent (n = 5) was performed in the main vessel with a 3.5-mm balloon catheter inflated to 6 atm. A second 3.5-mm balloon catheter was then inflated to 6 atm through the stent struts of the main vessel and into the ostium of the secondary vessel. The minimal lumen diameter (MLD) and cross-sectional area (CSA) at the ostium of the side branch and the stenosis within the main vessel were then measured, taking into account the stent deformity that occurred. Kissing balloon dilatation with two 3.5-mm balloon catheters was then performed and the stenosis secondary to stent deformity in the main vessel was remeasured. The MLD of the Multi-Link stent at the side-branch ostium was greater compared with those of the Palmaz-Schatz stent or the NIR stent (2.4 ± 0.1, 1.6 ± 0.1, 1.7 ± 0.1 mm, P &lt 0.01) and CSA (4.9 ± 0.5, 2.7 ± 0.3, 2.5 ± 0.3 mm2, P &lt 0.01). Balloon inflation through the stent struts caused stent deformity that resulted in some degree of stenosis within the stent of the main vessel in all three stent types. Kissing balloon inflation reduced, but never eliminated, this stenosis. The percent stenosis in the main vessel secondary to stent deformity (PS 34% ± 9%, NIR 25% ± 8%, Multi-Link 34% ± 7%, NS) and residual stenosis postkissing balloon inflation (PS 12% ± 1%, NIR 10% ± 3%, Multi-Link 14% ± 3%, NS) were not significantly different among these three stents. At the side-branch ostium, the MLD and CSA were significantly greater for the Multi-Link stent compared with those of the Palmaz-Schatz or NIR stent. Balloon inflation through the stent struts caused stent deformity that resulted in stenosis within the stent in the main vessel. Kissing balloon inflation reduced this stenosis, but some residual stenosis always remained. The stenoses within the main vessel did not differ among the three stent types.

Previous studies have shown that levels of plasma brain natriuretic peptide (BNP) increase in an early phase of acute myocardial infarction. However, the relations between plasma BNP levels and left ventricular remodelling, which occurs long after acute myocardial infarction, are not fully understood. Venous plasma BNP levels were measured 2, 7, 14, 30, 90 and 180 days after the onset of acute myocardial infarction in 21 patients. Left ventricular end-diastolic volume index (EDVI, ml/m2) in acute (5 days) and chronic (6 months) phases were assessed by electron-beam computed tomography using Simpson's method. The remodelling group (n = 9) was defined by an increase in EDVI ≥ 5 ml/m2 relative to the baseline value. Plasma BNP levels on days 2, 7, 14, 30 and 90 were significantly higher in the remodelling group than in the non-remodelling group (n = 12, P &lt 0.05). Sustained elevation of plasma BNP levels was noted from day 2 (61 ± 12 pmol/l) to day 90 (55 ± 12 pmol/l) and significantly decreased on day 180 (24 ± 3 pmol/l) in the remodelling group. In contrast, plasma BNP levels significantly decreased from day 2 (25 ± 4 pmol/l) to day 90 (9 ± I pmol/l) and reached a steady level thereafter in the non-remodelling group. Plasma BNP levels on day 7 correlated positively with an increase in EDVI (r = 0.70, P &lt 0.001) from the acute to chronic phase. More importantly, the sustained elevation of plasma BNP (percentage decrease smaller than 25%) from day 30 to day 90 identified patients in the remodelling group with a sensitivity of 100% and a specificity of 83%. In conclusion, not only the high levels of plasma BNP in an acute phase, but also the sustained elevation of plasma BNP in a chronic phase, may be associated with progressive ventricular remodelling occurring long after acute myocardial infarction.

Objectives. Stent implantation reduces restenosis in vessels greater than or equal to 3 mm compared with balloon angioplasty, but few data are available for stents implanted in vessels <3 mm. The aim of this study was to evaluate immediate and follow-up patient outcomes after stent implantation in vessels <3 mm compared to stent implantation in vessels greater than or equal to 3 mm. Methods. Between March 1993 and May 1996, a total of 1,298 consecutive patients (1,673 lesions) underwent coronary stenting. The study population was divided into two groups based on angiographic vessel diameter. In case of multivessel stenting, patients were randomly assigned only one lesion. Group I included 696 patients (696 lesions) in whom stents were implanted in vessels greater than or equal to 3 mm, and group II included 602 patients (602 lesions) in whom stents were implanted in vessels <3 mm. Results. There was no difference in procedural success (95.4% in group I and 95.9% in group II), or subsequent subacute stent thrombosis (1.5% in group I and 1.4% in group II p = NS). The postprocedure residual diameter stenosis was 3.31 +/- 12.4% in group I and -2.45 +/- 16.2% in group II. Angiographic follow-up was performed in 75% of patients, restenosis occurred in 19.9% of patients in group I and 32.6% in group II (p <0.0001). Absolute lumen gain was significantly higher in group I compared to group II, but absolute late lumen loss was similar in the two groups (1.05 +/- 0.91 mm in group I vs. 1.11 +/- 0.85 mm in group II, p NS). Subsequently, the loss index was more favorable in group I [0.45 vs. 0.56; p = 0.0006). Independent predictors of freedom from restenosis by multivariate logistic regression in the total population were: larger baseline reference diameter (odds ratio 2.032 p = 0.006, larger postprocedure minimal stent cross-sectional area (odds ratio 1.190, p = 0.0001) and shorter lesions (odds ratio 1.037, p = 0.01). At long term clinical follow up, patients with small vessels had a low er rate of event free survival (63% vs. 71.3%, p = 0.007), Conclusions. Coronary stenting can be performed in small vessels with a high success rate and low incidence of stent thrombosis. However, the long-term angiographic and clinical outcome of patients undergoing stent implantation in small vessels is less favorable than that of patients with large vessels. (J Am Coll Cardiol 1998;32:1610-8) (C)1998 by the American College of Cardiology.

The present study evaluated acute and late results with stenting following directional coronary atherectomy (DCA) for the lesions in the left anterior descending coronary artery (LAD). Between April 1995 and January 1997, 200 LAD lesions with greater than or equal to 3 mm reference vessel diameter were treated with coronary stents, The lesions were divided as to whether or not DCA was performed before stenting; 1) stenting alone (n = 163) and 2) debulking and stenting (n = 37). There were no significant differences in the incidences of complications except for non-Q-wave myocardial infarction that was more frequent in patients with debulking and stenting than in those with stenting alone (13.5% vs, 2.4%, P < 0.05), A greater acute lumen gain (2.85 +/- 0.66 vs. 2.25 +/- 0.60 mm, P < 0.01) and minimal lumen diameter (3.64 +/- 0.56 vs. 3.15 +/- 0.41 mm, P < 0.01) after stenting were observed in patients with debulking and stenting than in those with stenting alone. At follow-up patients with debulking and stenting continued to have a greater minimal lumen diameter (2.88 +/- 0.72 vs, 2.15 +/- 0.85 mm, P < 0.01) and had a lower restenosis rate (6.3% vs. 23.1%, P < 0.05) than those with stenting alone. Stenting following DCA appears to be advantageous in the LAD lesions with greater than or equal to 3 mm reference vessel diameter. (C) 1998 Wiley-Liss, Inc.

Background-Coronary stenting has reduced restenosis in focal de novo lesions, but its impact has been less pronounced in complex lesion subsets. Preliminary data suggest a role for plaque burden in promoting intimal hyperplasia after stent implantation. The aim of this study was to test the hypothesis that plaque removal with directional atherectomy before stent implantation may lower the intensity of late neointimal hyperplasia, reducing the incidence of in-stent restenosis. Methods and Results-Seventy-one patients with 90 lesions underwent directional atherectomy before coronary stenting. Intravascular ultrasound-guided stenting was performed in 73 lesions (81%). Clinical success was achieved in 96% of patients. Procedural complications were as follows: emergency bypass surgery in I patient (1.4%), who died 2 weeks later; Q-wave myocardial infarction in 2 patients (2.8%); and non-Q-wave myocardial infarction in 8 patients (11.3%). None of the patients had stent thrombosis at follow-up. Angiographic follow-up was performed in 89% of eligible patients at 5.7+/-1.7 months. Loss index was 0.33 (95% CI, 0.26 to 0.40), and angiographic restenosis was 11% (95% CI, 5% to 20%). Clinical follow-up was performed in all patients at 18+/-3 months. Target lesion revascularization was 7% (95% CI, 3% to 14%). Conclusions-Directional atherectomy followed by coronary stenting could be performed with good clinical success rate. Also, these data point to a possible reduction in angiographic restenosis and a significant reduction in the need for repeated coronary interventions. Therefore, a randomized clinical trial seems appropriate to lest the validity of this approach.

Objectives. This study sought to compare the short- and longterm outcomes of elderly patients undergoing coronary artery stenting with those of younger patients and to determine the long-term clinical outcome and survival of elderly patients post stent implantation. Background. Elderly patients undergoing coronary revascularization are considered a high-risk group. Few data exist that relate the results of stenting in treating coronary artery disease in the elderly population. Methods. All elderly patients greater than or equal to 75 years of age who underwent coronary artery stenting between March 1993 and July 1997 (n = 137) at our center were compared to the patients <75 who underwent coronary artery stenting during the same time period (n = 2,551). Long-term clinical follow-up and survival were determined for the elderly group. Results. Elderly patients presented,vith lower ejection fractions (54% vs. 58%, p = 0.0001), more unstable angina (47% vs. 28%, p = 0.0001), and more multivessel disease (78% vs. 62%, p = 0.0001) than younger patients. These older patients had higher rates of procedure related complications including procedural myocardial infarction (MI) (2.9% vs. 1.7%, p = 0.2), emergency CABG (3.7% vs. 1.4%, p = 0.04), and death (2.2% vs. 0.12%, p = 0.0001). Angiographic follow-up, obtained in both groups, demonstrated significantly higher restenosis rates in the elderly versus younger patients (47% vs. 28%, p = 0.0007). Longer term clinical follow-up, which was obtained only in the elderly group, showed that at a mean follow-up period of 12 months post coronary stenting, elderly survival free from death, MZ, revascularization and angina was 54% and that their overall survival was 91%. Subanalysis of the elderly patients who died showed much higher incidence of combined unstable angina (80%), prior MI (60%), lower ejection fraction (46%), multivessel disease (100%) and complex lesions (100%) than the overall group. Conclusions. Elderly patients who undergo coronary artery stenting have significantly higher rates of procedural complications and worse six month outcomes than younger patients, especially those who present with combined unstable angina, history of MI, EF < 50%, multivessel disease and complex lesions. Overall survival in the elderly population at 12 months postcoronary artery stenting was 91% and event-free survival was 54%. (J Am Coil Cardiol 1998;32:577-83) (C) 1998 by the American College of Cardiology.