Teruo Okabe

The potential clinical utility of intravascular ultrasound guidance in patients undergoing percutaneous coronary intervention with drug-eluting stents

AIMSnTo assess the impact on clinical outcomes of intravascular ultrasound (IVUS) guidance during drug-eluting stent (DES) implantation. IVUS guidance during percutaneous coronary intervention (PCI) has been demonstrated to be useful in optimizing stent deployment. However, it is not proved that routine use of IVUS guidance with DES implantation can prevent stent thrombosis or restenosis.nnnMETHODS AND RESULTSnThe clinical outcomes of 884 patients undergoing IVUS-guided intracoronary DES implantation from April 2003 to May 2006 were compared with the outcomes of a propensity-score matched population undergoing DES implantation with angiographic guidance alone. The primary endpoint of the study was definite stent thrombosis at 12 months. The secondary endpoint was major adverse cardiac events (MACE). After propensity-score matching, the two groups were well matched for clinical and angiographic characteristics. Patients undergoing IVUS-guided DES implantation underwent less direct stenting, more post-dilation, and had greater cutting balloon and rotational atherectomy use. At 30 days and at 12 months, a higher rate of definite stent thrombosis was seen in the No IVUS group (0.5 vs. 1.4%; P = 0.046) and (0.7 vs. 2.0%; P = 0.014), respectively. There were no major differences in late stent thrombosis and MACE (14.5 vs. 16.2%; P = 0.33) at 12 month follow-up between the groups. Rates of death and Q-wave myocardial infarction were similar, and there was no significant difference between groups in target vessel revascularization. However, a trend was seen in favour of the IVUS group in target lesion revascularization (5.1 vs. 7.2%; P = 0.07). IVUS guidance was an independent predictor of freedom from cumulative stent thrombosis at 12 months (adjusted HR 0.5, CI 0.1-0.8; P = 0.02).nnnCONCLUSIONnIVUS guidance during DES implantation has the potential to influence treatment strategy and reduce both DES thrombosis and the need for repeat revascularization.

Attenuated Plaque Detected by Intravascular Ultrasound : Clinical, Angiographic, and Morphologic Features and Post-Percutaneous Coronary Intervention Complications in Patients With Acute Coronary Syndromes

OBJECTIVESnWe evaluated the clinical significance of attenuated plaque (hypoechoic plaque with deep ultrasound attenuation).nnnBACKGROUNDnAttenuated plaques are unusual intravascular ultrasound (IVUS) findings in patients with acute coronary syndrome (ACS).nnnMETHODSnWe reviewed clinical presentations and angiographic and pre-intervention IVUS findings in 293 ACS patients undergoing percutaneous coronary intervention (PCI) without a distal protection device: 187 with non-ST-segment elevation myocardial infarction (NSTEMI) and 106 with ST-segment elevation myocardial infarction (STEMI).nnnRESULTSnAttenuated plaque was observed in 75 patients (25.6%): 39.6% of STEMI versus 17.6% of NSTEMI (p < 0.001). (We also reviewed 100 randomly selected patients with stable angina and pre-intervention IVUS; none had attenuated plaque.) Overall, in ACS patients with attenuated plaques: 1) the level of C-reactive protein was higher; 2) angiographic thrombus and initial coronary flow Thrombolysis In Myocardial Infarction flow grade <2 were more common; and 3) IVUS lesion site plaque burden and remodeling index were significantly greater, lesion site luminal dimensions significantly smaller, and thrombus, positive remodeling, and plaque rupture were more common. No-reflow (26.7% vs. 4.6%, p < 0.001) and deteriorated post-PCI coronary blood flow (8.0% vs. 2.8%, p = 0.001) were higher. In ACS patients with normal coronary blood flow at baseline, deterioration in the coronary blood flow post-PCI was more common in lesions with attenuated plaque.nnnCONCLUSIONSnAttenuated plaque was more common in ACS patients with STEMI than NSTEMI. Attenuated plaque in ACS patients was associated with a higher C-reactive protein level, more severe and complex lesion morphology, reduced coronary blood flow before PCI, and especially no-reflow after PCI.

Optical coherence tomography and intravascular ultrasound imaging of bioabsorbable magnesium stent degradation in porcine coronary arteries.

BACKGROUNDnAbsorbable metallic stents (AMS) composed of magnesium alloy were designed to complete degradation within 90-120 days. Among the potential advantages of these stents, when compared to conventional stents, are the elimination of late stent thrombosis, chronic inflammation, and artifacts during noninvasive imaging.nnnMETHODSnMagnesium-based AMS were deployed in juvenile domestic pig coronary arteries. Angiography, optical coherence tomography (OCT), and intravascular ultrasound (IVUS) were performed before and after implant and then at 28 days and 3 months following stenting. The animals were sacrificed at 28 days or 3 months following stent implantation. Stented vessels were harvested and analyzed by histomorphometry.nnnRESULTSnOver time, OCT, IVUS, and histologic images revealed a progressive degradation of the stents. Mean stent strut width in the OCT images after implantation was 0.24+/-0.032 mm, then decreased to 0.12+/-0.007 mm (P<.0001) at 28 days and to 0.151+/-0.032 mm at 3 months (P<.0001 vs. implant, P=.078 vs. 28 days).nnnCONCLUSIONnMagnesium-based AMS degrade over a 3-month time period in a porcine model. Its structure is not apparent by angiography but is well-visualized by OCT and IVUS. OCT allowed quantitative assessment of stent degradation.

Impact of plaque composition on cardiac troponin elevation after percutaneous coronary intervention: an ultrasound analysis.

OBJECTIVESnWe used virtual histology-intravascular ultrasound (VH-IVUS) to study the relationship between pre-percutaneous coronary intervention (PCI) coronary plaque characteristics and post-PCI cardiac troponin I (cTnI) elevation.nnnBACKGROUNDnPercutaneous coronary intervention is often complicated by post-procedural myocardial necrosis as manifested by elevated cardiac markers.nnnMETHODSnEighty consecutive patients (29 stable and 51 unstable angina) with normal pre-PCI cTnI levels were imaged before PCI using VH-IVUS. Patients were divided into 2 groups according to the presence (Group I, n = 38) or absence (Group II, n = 42) of post-PCI cTnI elevation > or =3x the upper limit of normal (0.08 ng/ml).nnnRESULTSnThe absolute and percent necrotic core volumes were significantly greater in Group I than in Group II (13.6 +/- 6.4 mm(3) vs. 7.9 +/- 4.4 mm(3), p < 0.001, and 19.8 +/- 10.4% vs. 12.8 +/- 8.4%, p = 0.015, respectively). The absolute and percent necrotic core areas were significantly greater in Group I than in Group II at the minimum lumen site (1.70 +/- 0.91 mm(2) vs. 0.61 +/- 0.39 mm(2), p < 0.001, and 22.9 +/- 11.7% vs. 10.4 +/- 6.6%, p < 0.001, respectively) and at the largest necrotic core site (2.00 +/- 0.86 mm(2) vs. 0.81 +/- 0.78 mm(2), p < 0.001, and 24.0 +/- 11.7% vs. 12.9 +/- 6.6%, p < 0.001, respectively). The DeltacTnI correlated with: 1) absolute and percent necrotic core area at the minimum lumen site and at the largest necrotic core site; 2) absolute necrotic core volume; 3) percent fibrofatty area at the minimum lumen site; and 4) lesion site plaque burden. In the multivariate analysis, absolute necrotic core area at the minimum lumen site was the only independent predictor of post-PCI cTnI elevation > or =3x the upper limit of normal (odds ratio: 1.318; 95% confidence interval: 1.090 to 1.594, p = 0.004).nnnCONCLUSIONSnThe VH-IVUS analysis shows that post-PCI cTnI elevation occurs in lesions with a large necrotic core area. The VH-IVUS may play an important role in detecting which lesions are high risks for myocardial necrosis after PCI.

Temporal relation between Clopidogrel cessation and stent thrombosis after drug-eluting stent implantation.

The risk of late thrombotic events and the need for prolonged dual antiplatelet therapy detract from the clinical advantage offered by drug-eluting stents (DESs). Short-term studies have shown premature clopidogrel cessation to be a strong predictor of stent thrombosis (ST) after DES implantation. Data pertaining to the utility of clopidogrel therapy and its optimal duration to prevent late ST remain limited. The study population consisted of 2,889 patients who underwent unrestricted intracoronary DES implantation from April 2003 to January 2007 for whom clopidogrel compliance data were available. Definite ST proved by angiography or autopsy within 12 months of the index procedure occurred in 61 patients. Comparisons of clinical and procedural characteristics in addition to outcomes (death and Q-wave myocardial infarction) were made between the ST and no-ST (2,828 patients) groups. Clopidogrel compliance was assessed at all follow-up time points. For patients in the ST group, clopidogrel compliance status for the remaining study period was defined as that at the time of ST. Logistic regression analysis was performed at 30 days, 6 months, and 12 months to identify independent predictors of cumulative ST. Patients with ST were more likely to have previous congestive heart failure and worse left ventricular ejection fraction. ST was associated with significantly higher mortality at 12 months (23.5% vs 3.2%, p <0.001). Clopidogrel compliance was 80.2% in the overall population and 73.8% in patients presenting with ST (82.6% in patients presenting with early ST and 43.8% in those with late ST). By logistic regression analysis, clopidogrel cessation was an independent predictor of cumulative ST at 30 days and 6 months but not at 12 months. In conclusion, high rates of clopidogrel compliance can be achieved in contemporary practice. Clopidogrel cessation by 12 months is no longer predictive of ST, thus suggesting the optimal duration of therapy for the prevention of ST to be 6 to 12 months.

Treatment of drug‐eluting stent restenosis with the same versus different drug‐eluting stent

The authors aimed to compare the clinical outcomes with repeat drug‐eluting stent (DES) implantation utilizing the same type versus an alternate DES type for in‐stent restenosis (ISR) of DES.

Impact of “Off-Label” Utilization of Drug-Eluting Stents on Clinical Outcomes in Patients Undergoing Percutaneous Coronary Intervention

The utilization of drug-eluting stents (DES) in real world practice has deviated from Food and Drug Administration-approved indications. Safety concerns have arisen from recent reports that suggested increased mortality and nonfatal myocardial infarction (MI) with DES usage. Little is known about the clinical outcomes of patients undergoing intracoronary DES implantation for unapproved indications as a group compared with outcomes after bare metal stent (BMS) placement. The clinical outcomes of 546 patients undergoing DES implantation for >or=1 non-Food and Drug Administration-approved (off label) indication since the approval of the device were assessed. The group was then matched by propensity score with 546 patients receiving BMSs prior to DES approval for the same indications. The primary endpoint was major adverse cardiac events (cardiac death, nonfatal Q-wave myocardial infarction [MI], and target vessel revascularization) at 12 months. Baseline clinical and angiographic characteristics were well matched between BMS and DES groups. The use of debulking devices was higher in the BMS group. Patients in the BMS group were more likely to be treated with larger diameter and shorter stents. There was no significant difference in the rate of in-hospital and 30-day adverse cardiac events. At 12 months, the primary endpoint of major adverse cardiac events was significantly reduced in the DES group (23.6% vs 16.7%, p=0.004), driven by reductions in the need for repeat revascularization (target lesion revascularization: 16.4% vs 7.8%, p<0.001; target vessel revascularization: 20.2% vs 13.1%, p=0.003). There was no significant difference in freedom from cardiac death or nonfatal Q-wave MI between groups (p=0.27). In conclusion, the utilization of DES for non-Food and Drug Administration-approved indications proved to be efficacious and safe when compared with a BMS cohort matched by propensity score. The advantage for DES was driven by reductions in repeat revascularization. Off-label DES use was not associated with increased rates of cardiac death and nonfatal MI at 12 months.

Observations and Outcomes of Definite and Probable Drug-Eluting Stent Thrombosis Seen at a Single Hospital in a Four-Year Period

Stent thrombosis (ST) is a major safety concern after drug-eluting stent (DES) deployment, resulting in significant morbidity and mortality. The goal of this study was to examine the incidence, timing, clinical correlates, and outcomes after DES thrombosis in a real-world population. A retrospective analysis of 8,402 patients who underwent percutaneous coronary intervention and received a DES was performed. After DES implantation, 84 definite (DST) and 127 probable ST events occurred. The incidence of early DST was 0.8%, late DST was 0.4%, and very late DST was 0.4%. Multivariate analysis showed that a history of diabetes mellitus, myocardial infarction during admission, number of stents, and DES placement in a restenotic lesion were independently associated with DST. The incidence of early definite or probable ST (DPST) was 1.9%, late DPST was 1.4%, and very late DPST was 0.7%. Multivariate analysis showed that a history of diabetes, myocardial infarction during admission, cardiogenic shock, number of stents, and DES use in a restenotic lesion were independently associated with DPST. Both types of ST were associated with significantly higher rates of all-cause death, Q-wave myocardial infarction, and revascularization up to 24 months after DES implantation. In conclusion, ST after DES implantation in contemporary practice continues to occur from 30 days to 2 years at a rate > or =0.36%/year and is associated with high rates of morbidity and mortality. Diabetes mellitus, myocardial infarction, and DES use in a restenotic lesion were strongly associated with DST; therefore, careful consideration should apply when deploying a DES in these populations.

Drug-eluting stents versus bare metal stents for narrowing in saphenous vein grafts.

Conflicting data exist regarding an advantage of drug-eluting stents (DES) over bare metal stents (BMS) in catheter-based treatment of saphenous vein graft (SVG) stenoses. This study was undertaken to compare the efficacy of these modalities in that lesion subset. The DES group consisted of 138 cases with 183 lesions (sirolimus-eluting stents, n = 117; paclitaxel-eluting stents, n = 66) and the BMS group consisted of 344 cases with 478 lesions that were followed to 1 year. We examined a composite end point that comprised death, Q-wave myocardial infarction, and target lesion revascularization. More BMS were deployed per patient (p <0.001) and the diameters of BMS deployed was significantly greater (p <0.001). Peak postprocedure values of creatine kinase-MB (p = 0.003) and troponin I (p = 0.05) were higher in BMS. At 1 year there was no significant superiority of DES over BMS with regard to hard end points (death and Q-wave myocardial infarction). In conclusion, this study indicates that both DES and BMS for SVG disease provide acceptably safe and efficacious results, but unlike the case in native coronary arteries, DES use does not reduce the frequency of the need for repeat revascularization.

Requirement for Emergent Coronary Artery Bypass Surgery Following Percutaneous Coronary Intervention in the Stent Era

Performance of percutaneous coronary intervention (PCI) at centers without cardiothoracic surgery is a contentious issue. Although this practice allows greater access to care, there are safety concerns. The aim was to assess the requirement for emergent coronary artery bypass grafting (CABG) after PCI and characterize patients at highest risk using independent predictors. The study population consisted of 21,957 unselected patients who underwent PCI from August 1994 (Food and Drug Administration stent approval) to January 2008 at a single medical center. Patients requiring emergent CABG (defined as within 24 hours of the index procedure) were identified. Logistic regression analysis was performed to assess for independent correlates of emergent CABG. Emergent CABG was required in 90 patients (cumulative incidence 0.41%). Indications for CABG included triple-vessel disease, dissection, acute closure, perforation, and failure to cross. These patients had significantly higher in-hospital cardiac death rates (7.8% vs 0.7%; p <0.01) and higher rates of Q-wave myocardial infarction, neurologic events, and renal insufficiency. Independent correlates of emergent CABG after PCI were acute ST-segment elevation myocardial infarction presentation, cardiogenic shock, triple-vessel disease, and type C lesion. Risk assessment based on these predictors identified 0.3% of the patient population to have a 9.3% cumulative incidence of emergent CABG. In conclusion, the need for emergent CABG after PCI in the stent era was low and was associated with poor in-hospital outcomes. Risk was nonuniform, with 0.3% of the study population, characterized by acute presentation and complex coronary disease, at heightened risk of emergent surgery.