Prognostic influence of diabetes mellitus on long-term clinical outcomes and stent thrombosis after drug-eluting stent implantation in asian patients

Diabetes mellitus has been associated with an increased risk of mortality and stent thrombosis after implantation of drug-eluting stents (DES). Little is known about the prognostic impact of diabetes on clinical outcomes in an Asian population treated with DES. We compared adverse outcomes between 865 patients with diabetes and 2,295 patients without diabetes treated with DES after adjustment for differences in baseline risk factors in the patients. The primary outcome was the composite of death, nonfatal myocardial infarction, or target-vessel revascularization (TVR). The 3-year unadjusted rates of death (5.8% vs 3.5%, p = 0.002) and TVR (12.2% vs 8.6%, p = 0.003) were significantly higher in patients with diabetes. After adjustment for baseline differences, the risk of TVR remained higher in patients with diabetes (hazard ratio 1.37, 95% confidence interval [CI] 1.04 to 1.81, p = 0.03), but the risk of death did not (hazard ratio 1.35, 95% CI 0.89 to 2.05, p = 0.16). The 3-year adjusted risk of the primary composite outcome was significantly higher in patients with diabetes compared with patients without diabetes (23.3% vs 16.1%, hazard ratio 1.24, 95% CI 1.02 to 1.51, p = 0.03). Insulin use was an independent predictor for each outcome (death, TVR, and composite outcome). After adjustment by baseline risk profile and for propensity, diabetes was not associated with an increased risk of stent thrombosis (multivariable-adjusted hazard ratio 0.87, 95% CI 0.36 to 2.15, p = 0.77 and propensity-adjusted hazard ratio 0.87, 95% CI 0.37 to 2.06, p = 0.76). In conclusion, diabetic status was associated with increased TVR without a significantly increased rate of death. A diabetes-associated excess risk of stent thrombosis was not observed in Asian patients.

Assessment and key targets for therapy in the post-myocardial infarction patient with left ventricular dysfunction

In the post-myocardial infarction (MI) patient with coronary artery disease (CAD) and left ventricular dysfunction (LVD), ischemia and adverse remodeling hinder myocardial performance and increase electrical instability. Collectively, the coronary arteries, myocardium, and conduction system represent the principal pathophysiologic targets in MI complicated by LVD. Consequently, an accurate assessment of disease severity in these targets is essential for the design of an effective therapeutic program. This review describes the current modalities for assessing the key pathophysiologic targets in post-MI patients with LVD and the effects of systemic factors on cardiac disease severity.

Predictive value of dobutamine stress echocardiography for coronary artery disease detection in liver transplant candidates

Patients with obstructive coronary artery disease (CAD) undergoing orthotopic liver transplantation (OLT) are at increased risk of poor outcomes. The accuracy of dobutamine stress echocardiography (DSE) to detect obstructive CAD is not well established in this population. We retrospectively identified patients with end-stage liver disease who underwent both DSE and coronary angiography as part of risk stratification prior to OLT. One hundred and five patients had both DSE and angiography, of whom 14 had known CAD and 27 failed to reach target heart rate during DSE. Among the remaining 64 patients (45 men; average age 61 +/- 8 years) DSE had a low sensitivity (13%), high specificity (85%), low positive predictive value (PPV) (22%) and intermediate negative predictive value (NPV) (75%) for obstructive CAD. DSE as a screening test for obstructive CAD in OLT candidates has a poor sensitivity. The frequent chronotropic incompetence and low sensitivity in patients who achieve target heart rate, even in those with multiple cardiovascular disease risk factors, suggest that alternative or additional methods of risk stratification are necessary.

Contrast media: procedural capacities and potential risks

Contrast media are known to have transient hemodynamic properties that can influence a patient's clinical status, including heart rate variability and blood pressure. These changes have the potential to impact the diagnostic quality of CT scans. Although most patients are able to receive contrast media without significant adverse reactions, events occur in a minority of cases. These reactions range from mild discomfort (injection-associated pain and heat sensation) to more significant cardiac, renal, and hypersensitivity reactions. The incidence of adverse reactions varies with the type of contrast media used, and several randomized trials have elucidated the cardiac and renal differences among agents. Risk factors for contrast-induced acute kidney injury (CIAKI) have been established, with baseline kidney disease amplified by the presence of diabetes constituting the highest-risk patient group. Strategies for preventing CIAKI include antioxidant therapy, hydration regimens, and choice of contrast agents. Enhanced knowledge on the part of physicians and medical personnel regarding the properties and potential side effects of iodinated contrast agents should lead to improved patient safety and efficacy when performing radiologic examinations.

Angiographic estimates of myocardium at risk during acute myocardial infarction: validation study using cardiac magnetic resonance imaging

AIMS

Global angiographic scores have been developed to determine the extent of myocardium jeopardized by significant coronary stenosis. We adapted these scores to quantify the anatomic area at risk during acute myocardial infarction. We used contrast-enhanced magnetic resonance (CMR) infarct imaging to measure the portion of myocardium that developed necrosis within the so defined angiographic area at risk.

METHODS AND RESULTS

In 83 subjects presenting for primary percutaneous intervention, the myocardium at risk was estimated angiographically using the Myocardial Jeopardy Index (BARI) and a modified version of the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) scores. CMR was performed within a week to measure infarct size, infarct endocardial surface area (infarct-ESA), and infarct transmurality. As infarct transmurality increased, the infarct size closely approximated the myocardium at risk by angiography. In 35 subjects with transmural infarcts, the area at risk by BARI and APPROACH scores matched the infarct size (r = 0.90 and r = 0.92, P < 0.001). Additionally, BARI and APPROACH scores matched the infarct-ESA in all subjects independently of collateral flow and time to reperfusion (r = 0.90 and r = 0.87, P < 0.001). The presence of early reperfusion, collaterals, or both was associated with a progressive decrease in infarct transmurality (P < 0.001 for trend) with no difference in the infarct-ESA.

CONCLUSION

The myocardium at risk of infarction can be determined angiographically as validated in subjects with transmural myocardial infarcts. Salvage provided by early reperfusion or collaterals occurs by limiting infarct transmurality, thereby the extent of endocardial infarct involved also allows estimation of the myocardium at risk in patients presenting with STEMI.

Outcomes and complications associated with off-label and untested use of drug-eluting stents

CONTEXT

Limited data exist regarding use of drug-eluting stents outside of approved indications in real-world settings.

OBJECTIVES

To determine the frequency, safety, and effectiveness of drug-eluting stents for off-label (restenosis, bypass graft lesion, long lesions, vessel size outside of information for use recommendation) and untested (left main, ostial, bifurcation, or total occlusion lesions) indications in percutaneous coronary intervention (PCI).

DESIGN, SETTING, AND PATIENTS

Observational, prospective, multicenter registry to evaluate in-hospital, 30-day, and 1-year outcomes among patients undergoing PCI between January and June 2005 in 140 US academic and community medical centers. Of 7752 PCI-treated patients, 6993 (90%) received drug-eluting stents; of these, 5851 (84%) received no other devices. Standard, off-label, and untested use was determined in 5541 (95%) of these 5851 patients, constituting the study cohort.

MAIN OUTCOME MEASURES

Frequency of off-label and untested use, 1-year repeat target vessel revascularization, and composite of death, myocardial infarction (MI), or stent thrombosis at in-hospital follow-up and during 1 year of follow-up.

RESULTS

Of 5541 patients receiving drug-eluting stents, 2588 (47%) received stents for off-label or untested indications. Adjusted in-hospital risk of death, MI, or stent thrombosis was not statistically different with off-label or untested vs standard use. At 30 days, the risk of this composite end point was significantly higher with off-label use (adjusted hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.24-3.48; P = .005) but not untested use (adjusted HR, 1.45; 95% CI, 0.79-2.67; P = .23). Excluding early events, this end point was not different at 1 year with off-label use (adjusted HR, 1.10; 95% CI, 0.79-1.54; P = .57) or untested use (adjusted HR, 0.91; 95% CI, 0.60-1.38; P = .66). At 1 year, compared with standard use, significantly higher rates of target vessel revascularization were associated with off-label use (adjusted HR, 1.49; 95% CI, 1.13-1.98; P = .005) and untested use (adjusted HR, 1.49; 95% CI, 1.10-2.02; P = .01), although absolute rates were low (standard, 4.4% [n = 113]; off-label, 7.6% [n = 95]; untested, 6.7% [n = 72]).

CONCLUSIONS

In contemporary US practice, off-label and untested use of drug-eluting stents is common. Compared with standard use, relative early safety is lower with off-label use, and the long-term effectiveness is lower with both off-label and untested use. However, the absolute event rates remain low.

Granulocyte-colony stimulating factor administration after myocardial infarction in a porcine ischemia-reperfusion model: functional and pathological effects of dose timing

BACKGROUND

Acute MI results in cardiomyocyte death, left ventricular (LV) dysfunction and adverse remodeling. The use of growth factors may prevent this. The aim of this study was to assess early and delayed administration of granulocyte colony-stimulating factor (G-CSF) in a porcine model of myocardial infarction (MI) and reperfusion.

METHODS

MI was induced by balloon occlusion followed by reperfusion. There were 3 groups: Control (n = 11), Early (n = 17), and Delayed treatment (n = 8). The Early group received G-CSF 10 microg/kg/d every other day for 20 days beginning immediately. The Delayed group received G-CSF 10 microg/kg/d daily for 10 days beginning on day 5. Magnetic resonance imaging was performed on days 5 and 56. LV end-diastolic volumes (EDV), end-systolic volumes, ejection fraction, expansion index, sphericity index, thinning ratio, and infarct mass were calculated. Histology was analyzed at 56 days.

RESULTS

At 56 days the change in EDV was 53% less in the Early (p = 0.005) and 24% greater in the Delayed (p = NS) group versus Control. The Delayed group also showed a 60% increase in normalized infarct mass (p = 0.055) and an 88% increase in expansion index (p = 0.003). Both groups had significantly less capillary density in the infarct border zone. The Delayed also had decreased arteriolar density in the mid scar.

CONCLUSIONS

Early treatment with G-CSF after MI decreases ventricular dilatation, while delayed treatment has a deleterious effect on LV remodeling. This may be related to changes in myocardial vascularity. The effects of G-CSF therapy and its dose timing help to elucidate the results of recent human trials.

Prevention of contrast induced nephropathy: recommendations for the high risk patient undergoing cardiovascular procedures

Contrast induced nephropathy (CIN) is the third leading cause of hospital acquired renal failure and is associated with significant morbidity and mortality. Chronic kidney disease is the primary predisposing factor for CIN. As estimated glomerular filtration rate<60 ml/1.73 m2 represents significant renal dysfunction and defines patients at high risk. Modifiable risk factors for CIN include hydration status, the type and amount of contrast, use of concomitant nephrotoxic agents and recent contrast administration. The cornerstone of CIN prevention, in both the high and low risk patients, is adequate parenteral volume repletion. In the patient at increased risk for CIN it is often appropriate to withhold potentially nephrotoxic medications, and consider the use of n-acetylcysteine. In patients at increased risk for CIN the use of low or iso-osomolar contrast agents should be utilized and strategies employed to minimize contrast volume. In these patients serum creatinine should be obtained forty-eight hours post procedure and it is often appropriate to continue withholding medications such as metformin or non steroidal anti-inflammatories until renal function returns to normal.

Percutaneous coronary intervention in a patient with cardiac dextroversion

Dextrocardia associated with atrial situs solitus is commonly referred to as dextroversion. Dextroversion is a result of early interruption of normal embryological development and, therefore, rarely occurs without other associated cardiac and noncardiac anomalies. While percutaneous coronary intervention has been described in many cases of dextrocardia with situs inversus, it has not been previously described in dextroversion. We report the case of an 88-year-old woman with dextroversion who presented with an acute anterior myocardial infarction that was successfully treated with coronary stent implantation.

Quantitative assessment of regional left ventricular function with cardiac MRI: Three-dimensional centersurface method

OBJECTIVES

The purpose of this study was to provide the first in vivo validation of a three-dimensional (3D) method to quantify regional left ventricular (LV) function with cardiac magnetic resonance (CMR) imaging after myocardial infarction (MI).

BACKGROUND

Current cardiac methods to analyze LV function are limited by geometric assumptions and observer biases.

METHODS

MI was induced percutaneously by 90-min proximal left circumflex artery balloon occlusion in 25 Yucatan minipigs. Cine and contrast-enhanced (CE) CMR imaging was performed at 5 days (n = 21) and 8 weeks (n = 22) post-MI. Twelve control animals without MI were also imaged. Regional wall thickening was measured orthogonal to the myocardial wall using the centersurface method. The left ventricle was divided into 16 segments (six basal 60 degrees , six middle 60 degrees , four apical 90 degrees ). Normal ranges for segmental wall thickness and wall thickening were defined as mean +/- 2D in control hearts. Hypokinesis was defined as a segmental thickening value below the normal range.

RESULTS

Hypokinesis following MI was identified in the inferior, inferolateral and anterolateral segments when compared with controls and corresponded to areas of infarction by CE CMR. The aggregate wall thickening was also expressed as a percentage at 5 days (Infarct zone: 15% +/- 16% vs. NonInfarct zone 33% +/- 20%, P < 0.001) and 8 weeks (Infarct zone 20% +/- 20% vs. NonInfarct zone 32% +/- 22%, P < 0.001).

CONCLUSIONS

The centersurface method can quantify regional wall thickening and spatially identify regions of abnormal function in 3D after MI without relying on geometric assumptions. This method may be a valuable tool to quantify regional LV function in the assessment of myocardial viability, ischemia, infarction, and the response to therapeutic interventions.

Quantitative assessment of in-stent dimensions: a comparison of 64 and 16 detector multislice computed tomography to intravascular ultrasound

OBJECTIVES

To determine the utility of multislice computed tomography (MSCT) technology to evaluate coronary stent luminal diameter.

BACKGROUND

Stent metal induced "blooming" artifact makes quantitative coronary angiography by MSCT difficult. There is a paucity of data on the efficacy of using 64 and 16 detector MSCT in evaluating coronary stents.

METHODS

We evaluated four commercially available bare metal and polymer coated drug eluting stents using 64 and 16 detector MSCT for the following: (1) Strut density in Hounsfield's Units (Hu) using a 2 mm MIP; (2) In-stent luminal diameter (ISLD) measured by MSCT compared to intravascular ultrasound (IVUS).

RESULTS

Increased strut thickness did not correlate with greater strut density as measured in Hu (R(2) = 0.05, P = 0.29). The ISLD by 16 MSCT vs. IVUS is: Vision 1.63 +/- 0.58 mm vs. 2.8 +/- 0.0; Cypher 1.80 +/- 0.00 vs. 2.9 +/- 0.0; Taxus 1.87 +/- 0.58 vs. 2.9 +/- 0.0; Liberté 1.80 +/- 0.10 vs. 3.0 +/- 0.1 (P < 0.01). ISLD determined by 64 MSCT vs. IVUS is: Vision 1.73 +/- 0.06 mm vs. 2.8 +/- 0.0; Cypher 1.87 +/- 0.12 vs. 2.9 +/- 0.0; Taxus 1.77 +/- 0.06 vs. 2.9 +/- 0.0; Liberté 1.80 +/- 0.10 vs. 3.0 +/- 0.1 (P < 0.01).

CONCLUSIONS

When compared to IVUS measurements, MSCT results in a significant, underestimation of ISLD. This consistent underestimation (even with 64 MSCT) limits the applicability of CT angiography to quantify in-stent restenosis.

Cardiac hemodynamic and coronary angiographic characteristics of patients being evaluated for liver transplantation

With improved survival after liver transplantation (LT), the referral of older candidates has increased. The increasing demand for, and the decreased supply of, liver donors makes careful preoperative cardiac risk assessment imperative. There is a paucity of information regarding the cardiac characteristics of patients being referred for LT in the current era. This study aimed to describe the cardiac hemodynamic and coronary angiographic characteristics of a cohort of patients with end-stage liver disease without known coronary artery disease (CAD) being evaluated for LT. One hundred sixty-one consecutive patients aged>or=45 years with end-stage liver disease who were referred for right- and left-sided cardiac catheterization as part of a liver transplant evaluation were identified. There was a high prevalence of atherosclerotic risk factors; half had hypertension or diabetes, and more than half had >or=2 coronary risk factors other than age. There was a high prevalence of CAD, with 26% having unknown moderate to severe coronary narrowing. Patients with moderate to severe CAD were older, were more likely to be men, and were more likely to have hypertension or diabetes mellitus. Right- and left-sided filling pressures were elevated, suggesting abnormalities in left ventricular diastolic compliance. In conclusion, this study showed a high prevalence of coronary risk factors and unknown moderate to severe CAD in patients with end-stage liver disease being referred for LT.

Contrast-Induced Nephropathy (CIN) Consensus Working Panel: executive summary

With the advances made in radiology and cardiology, greater numbers of patients are expected to undergo exposure to iodinated contrast media in the years to come. Contrast-induced nephropathy (CIN) accounts for a significant number of cases of hospital-acquired renal failure, with adverse effects on prognosis and healthcare costs. The CIN Consensus Working Panel is an international multidisciplinary group convened to address the challenges of CIN. The group reviewed 865 published papers, chosen for potential relevance from a comprehensive literature search that identified over 4000 references. The results were used to compile reviews covering the epidemiology and pathogenesis of CIN, baseline renal function measurement, risk assessment, identification of high-risk patients, contrast medium use, and preventive strategies. In this executive summary, consensus statements and an algorithm for the risk stratification and management of CIN are presented.

Hypersensitivity cases associated with drug-eluting coronary stents: a review of available cases from the Research on Adverse Drug Events and Reports (RADAR) project

OBJECTIVES

We undertook the review of all available cases of hypersensitivity reactions after placement of a drug-eluting stent (DES) and classified potential causes.

BACKGROUND

Six months after the approval of the first DES, the Food and Drug Administration (FDA) reported 50 hypersensitivity reactions after stent placement but later concluded these were due to concomitantly prescribed medications such as clopidogrel. Nevertheless, the FDA continued to receive reports of hypersensitivity.

METHODS

Reports available from April 2003 through December 2004 for hypersensitivity-like reactions associated with the sirolimus-eluting stent (CYPHER, Cordis Corp., Miami Lakes, Florida) and paclitaxel-eluting stent (TAXUS, Boston Scientific Corp., Natick, Massachusetts) were reviewed. Sources of reports included the FDA's adverse-device-event database, the published literature, and investigators from the Research on Adverse Drug/Device events And Reports (RADAR) project. Causality was assessed using standardized World Health Organization criteria.

RESULTS

Of 5,783 reports identified for the DES in the FDA database, 262 unique events included hypersensitivity symptoms. Of these reports, 2 were certainly and 39 unlikely caused by clopidogrel and 1 was certainly, 9 probably, and 13 unlikely caused by the DES. From all sources, we identified 17 distinct cases that were probably or certainly caused by the stent, of which 9 had symptoms that lasted longer than four weeks. Four autopsies confirmed intrastent eosinophilic inflammation, thrombosis, and lack of intimal healing.

CONCLUSIONS

The FDA reports and autopsy findings suggest that DES may be a cause of systemic and intrastent hypersensitivity reactions that, in some cases, have been associated with late thrombosis and death.

Impact of intracoronary aspiration thrombectomy during primary angioplasty on left ventricular remodelling in patients with anterior ST elevation myocardial infarction

OBJECTIVE

To evaluate prospectively the impact on left ventricular (LV) remodelling of an intracoronary aspiration thrombectomy device as adjunctive therapy in primary percutaneous coronary intervention (PCI) in patients with anterior ST elevation myocardial infarction (STEMI).

METHODS

76 consecutive patients with anterior STEMI (65.3 (11.2) years, 48 men) were randomly assigned to intracoronary thrombectomy and stent placement (n = 38) or to conventional stenting (n = 38) of the infarct related artery. Each patient underwent transthoracic echocardiography immediately after PCI and at six months. At the time of echocardiographic control, major adverse cardiovascular events (MACE) in terms of death, new onset of myocardial infarction, and hospitalisation for heart failure were also evaluated.

RESULTS

After a successful primary PCI, patients in the thrombectomy group achieved a higher rate of post-procedure myocardial blush grade 3 (36.8% v 13.1%, p = 0.03) and effective ST segment resolution at 90 minutes (81.6% v 55.3%, p = 0.02). Six months after the index intervention, 19 patients (26.8%) developed LV dilatation, defined as an increase in end diastolic volume (EDV) >or= 20%: 15 in the conventional group and four in the thrombectomy group (p = 0.006). Accordingly, at six months patients treated conventionally had significantly higher end systolic volumes (82 (7.7) ml v 75.3 (4.9) ml, p < 0.0001) and EDV (152.5 (18.1) ml v 138.1 (10.7) ml, p < 0.0001) than patients treated with thrombectomy. No differences in cumulative MACE were observed (10.5% in the conventional group v 8.6% in the thrombectomy group, not significant).

CONCLUSION

Compared with conventional stenting, adjunctive aspiration thrombectomy in successful primary PCI seems to be associated with a significantly lower incidence of LV remodelling at six months in patients with anterior STEMI.

The Research on Adverse Drug Events and Reports (RADAR) project

CONTEXT

In 1998, a multidisciplinary team of investigators initiated RADAR (Research on Adverse Drug events And Reports), a clinically based postmarketing surveillance program that systematically investigates and disseminates information describing serious and previously unrecognized adverse drug and device reactions (ADRs).

OBJECTIVE

To describe the structure, operations, and preliminary findings from the RADAR project and related dissemination efforts by pharmaceutical suppliers and the US Food and Drug Administration (FDA).

DESIGN

After identifying a serious and unexpected clinical event suitable for further investigation, RADAR collaborators postulated clinical hypotheses and derived case series and incidence estimates from physician queries, published and unpublished clinical trials, published case reports, FDA databases, and manufacturer sales figures.

RESULTS

RADAR investigators identified 16 types of serious ADRs among 1699 patients, of whom 169 (10%) died as a result of the reaction. Initial cases were identified by 7 RADAR investigators, 4 collaborating physicians, 2 attorneys, and by reviewing 3 published reports. Additional sources included queries of occupational health programs and medical directors of interventional cardiology laboratories (3 types of ADRs), published manuscripts and clinical trials (11 types of ADRs), review of medical records at a RADAR site (2 types of ADRs), unpublished clinical trial reports (3 types of ADRs), and reports from attorneys, family members, or patients (4 types of ADRs). Incidence estimates, ranging from 0.4% to 33%, were derived from 5 clinical trial reports, 2 physician queries, and 2 observational databases. Laboratory support for hypotheses included identification of 3 neutralizing antibodies and 3 histopathological findings. ADR reports were disseminated as 8 revised package inserts, 7 "dear doctor" letters, and 9 peer-reviewed articles.

CONCLUSION

A new, clinically based, hypothesis-driven approach to postmarketing surveillance may supplement existing regulatory surveillance systems and improve patient safety.

Diabetes and coronary revascularization

CONTEXT

Patients with diabetes mellitus account for approximately 25% of the nearly 1.5 million coronary revascularization procedures performed each year in the United States and experience worse outcomes compared with nondiabetic patients.

OBJECTIVES

To summarize the current state of evidence comparing the effectiveness and safety of coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) in diabetic patients and to examine developments that may affect future outcomes in this high-risk group.

EVIDENCE ACQUISITION

Using the key terms diabetes mellitus, revascularization, coronary artery bypass, angioplasty, and coronary intervention, we searched MEDLINE from 1985 to 2004 for all randomized controlled trials (RCTs) comparing CABG surgery and PCI that reported outcomes in diabetic patients. Bibliographies and the Web sites of cardiology conferences were also reviewed. Studies comparing drug-eluting stents and bare-metal stents were identified in a similar fashion. The literature was reviewed to identify clinical measures that may impact revascularization outcomes in diabetic patients.

EVIDENCE SYNTHESIS

We identified 6 RCTs comparing CABG surgery and PCI in a total of 950 diabetic patients. A mortality benefit for CABG over balloon-only PCI has been demonstrated in diabetic patients with multivessel coronary artery disease but has not been clearly established against stent-assisted PCI or in high-risk CABG patients. Use of glycoprotein IIb/IIIa receptor inhibitors has improved survival in diabetic patients undergoing PCI. Restenosis after PCI in diabetic patients has led to substantially higher repeat revascularization rates than after CABG. The use of drug-eluting stents has led to dramatic reductions in restenosis in diabetic patients. Ongoing RCTs comparing CABG and PCI using drug-eluting stents in diabetic patients will clarify the impact of these advances on outcomes.

CONCLUSIONS

There is a relative lack of data from RCTs specifically comparing CABG surgery and PCI as currently practiced in diabetic patients. The mortality advantage and decreased rates of revascularization seen with CABG in subgroups from early trials may not be applicable in the era of drug-eluting stents, glycoprotein IIb/IIIa inhibitors, and the latest medical therapies.

Myonecrosis following stent placement: association between impaired TIMI myocardial perfusion grade and MRI visualization of microinfarction

Contrast-enhanced cardiac MRI (ceMRI) and TIMI myocardial perfusion grade analysis (TMPG) are proven methods for visualization of microinfarction and assessment of microvascular perfusion, respectively. To determine whether microvascular obstruction accounts for procedure-related myonecrosis, 14 poststent patients, 9 with procedural CK-MB elevation and 5 controls, underwent ceMRI and TMPG. All had TIMI 3 flow pre- and poststent. TMPG was normal in 12/14 pre- and 7/14 poststent. Those with poststent decline in TMPG had higher CK-MB (median, 41.0 vs. 7.4 ng/mL; P = 0.01) and larger infarct mass (median, 3.1 vs. 0.89 g; P = 0.04). More extensive myonecrosis (CK-MB > 3 x normal; infarct mass > 3 g) was observed more frequently if there was a poststent decline in TMPG (3/3, 100%, vs. 2/11, 18.2%; P = 0.03). These data support the theory that distal embolization and microvascular obstruction are associated with myonecrosis following otherwise successful coronary stent placement and provide further insight into its pathophysiology.

Primary coronary intervention in acute myocardial infarction

Percutaneous coronary intervention (PCI) with stent implantation has become the standard of care for acute myocardial infarction <12 hours from symptom onset. This has led to decreased morbidity and mortality both short and long term compared to thrombolytic therapy. Stent implantation has been demonstrated to be superior to balloon PCI for mechanical reperfusion of acute myocardial infarction. Intravenous antiplatelet glycoprotein IIb/IIIa inhibitors may have a role in improving TIMI flow prior to PCI and decreasing morbidity and mortality. The role of thrombolytics vs. IIb/IIIa inhibitors in "facilitated reperfusion" is unclear at this time and further research is needed to define the indication of adjunctive pharmacology.

Antirestenotic Effects of a Locally Delivered Caspase Inhibitor in a Balloon Injury Model

BACKGROUND

The precise role of arterial barotrauma-mediated apoptosis in causing restenosis is unclear. The purpose of this study was to determine if a link exists between angioplasty-mediated medial smooth muscle cell apoptosis and subsequent neointimal hyperplasia.

METHODS AND RESULTS

Bilateral iliac artery angioplasty was performed in 25 male New Zealand White rabbits. Simultaneous with balloon injury, each artery was treated locally with either the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp(Ome)-fluoromethylketone (ZVAD-fmk) or control. In the acute cohort that was survived to 4 hours (n=10, 7 high dose and 3 low dose), an apoptotic index was calculated using the terminal deoxynucleotidyl TUNEL method. In the intermediate cohort that was survived to 2 weeks (n=5), luminal reendothelialization was measured via CD-31 staining. In the chronic cohort that was survived to 4 weeks (n=10), neointimal area was measured. In the acute cohort, there was a 40% reduction in the apoptotic index with high-dose ZVAD-fmk (P=0.008) and a 33% reduction with low-dose ZVAD-fmk (P=0.08). At 2 weeks, there was no significant difference in the degree of luminal reendothelialization. However, at 4 weeks, there was a 33% (0.33+/-0.23 versus 0.22+/-0.20 mm2) (P<0.005) reduction in neointimal area in ZVAD-fmk-treated arteries.

CONCLUSIONS

The local delivery of ZVAD-fmk during balloon injury inhibits smooth muscle cell apoptosis. This corresponds to a significant reduction in neointimal proliferation seen at 4 weeks without a significant change in the degree of reendothelialization at 2 weeks.