Defining the appropriate threshold of creatine kinase elevation after percutaneous coronary interventions

A Contemporary Definition of Periprocedural Myocardial Injury After Percutaneous Coronary Intervention of Chronic Total Occlusions

OBJECTIVES

The aim of this study was to assess the prognostic impact of post-procedural troponin T increase and mortality in patients undergoing percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) to define the threshold at which procedure-related myocardial injury drives mortality.

BACKGROUND

Coronary CTO recanalization represents the most technically challenging PCI. The complexity harbors a significant increased risk for complications with CTO PCI with compared with non-CTO PCI. However, there are evidenced biomarker cutoff levels that help identify those patients at risk for unfavorable clinical outcomes.

METHODS

A total of 3,712 consecutive patients undergoing PCI for at least 1 CTO lesion were enrolled, and comprehensive troponin T measurements were performed 6, 8, and 24 h after the procedure. All-cause mortality was defined as the primary study endpoint.

RESULTS

Using spline curve analysis, a more than 18-fold increase of troponin above the upper reference limit was significantly associated with mortality. In a Cox regression analysis, the crude hazard ratio was 2.32 (95% confidence interval: 1.83 to 2.93; p < 0.001) for a ≥18-fold increase compared with patients with post-procedural troponin increase <18-fold of the upper reference limit. Results remained virtually unchanged after bootstrap- or clinical confounder-based adjustment.

CONCLUSIONS

This large-scale outcome study demonstrates for the first time the prognostic value of post-procedural troponin T elevation after PCI in patients with CTOs. A threshold was defined for procedure-related myocardial injury in patients with CTOs to differentiate them from those without CTOs that may help guide post-procedural clinical care in this high-risk patient population.

Incidence, correlates, and significance of abnormal cardiac enzyme rises in patients treated with surgical or percutaneous based revascularisation: a substudy from the Synergy between Percutaneous Coronary Interventions with Taxus and Cardiac Surgery (SYNTAX) Trial

AIMS

The aim of the present investigation was to determine the long-term prognostic association of post-procedural cardiac enzyme elevation within the randomised Synergy between Percutaneous Coronary Intervention (PCI) with TAXUS and Cardiac Surgery (SYNTAX) Trial.

METHODS

1800 patients with unprotected left main or de novo three-vessel coronary artery disease were randomised to undergo coronary artery bypass graft (CABG) surgery or PCI. Per protocol patients underwent post-procedural blood sampling with creatine kinase (CK), and the cardiac specific MB iso-enzyme (CK-MB) only if the preceding CK ratio was ≥ 2 × the upper limit of normal (ULN). An independent chemistry laboratory evaluated all collected blood samples.

RESULTS

Post-procedural CK sampling was available in 1629 of 1800 patients (90.5%). As per protocol, CK-MB analyses were undertaken in 474 of 491 patients (96.5%) in the CABG arm, and 53 of 61 patients (86.9%) in the PCI arm. Within the CABG arm, despite the limitations of incomplete data, a post-procedural CK-MB ratio <3/≥3 ULN separated 4-year mortality into low- and high-risk groups (2.3% vs. 9.5%, p=0.03). Additionally, in the CABG arm, a post-procedural CK-MB ratio ≥3 ULN was associated with an increased frequency of a high SYNTAX Score (≥33) tertile (high [≥33] SYNTAX Score: 39.5%, intermediate [23-32] SYNTAX Score 31.0%, low [≤22] SYNTAX Score 29.5%, p=0.02). Within the PCI arm, a post-procedural CK ratio of <2 or ≥2 ULN separated 4-year mortality into low- and high-risk groups (10.8% vs. 23.3%, p=0.001). Notably, there was an early (within 6 months) and late (after 2 years) peak in mortality in patients with a post-PCI CK ratio of ≥2 ULN. Lack of pre-procedural thienopyridine, carotid artery disease, type 1 diabetes, and presence of coronary bifurcations were independent correlates of a CK ratio ≥2 ULN post-PCI.

CONCLUSION

Cardiac enzyme elevations post-CABG or post-PCI are associated with an adverse long-term mortality; the causes of which are multifactorial.

The index of microcirculatory resistance predicts myocardial infarction related to percutaneous coronary intervention

BACKGROUND

Periprocedural myocardial infarction (MI) occurs in a significant proportion of patients undergoing percutaneous coronary intervention (PCI) and portends poor outcomes. Currently, no clinically applicable method predicts periprocedural MI in the cardiac catheterization laboratory before it occurs. We hypothesized that impaired baseline coronary microcirculatory reserve, which reduces the ability to tolerate ischemic insults, is a risk for periprocedural MI and that the index of microcirculatory resistance (IMR) measured during PCI can predict occurrence of periprocedural MI.

METHODS AND RESULTS

Consecutive patients undergoing elective PCI of a single lesion in the left anterior descending coronary artery were recruited. A pressure-temperature sensor wire was used to measure IMR before PCI. Of the 50 patients studied, 10 had periprocedural MI. From binary logistic regression analyses of all clinical, procedural, and physiological parameters, univariable predictors of periprocedural MI were pre-PCI IMR (P=0.003) and the number of stents used (P=0.039). Pre-PCI IMR was the only independent predictor in bivariable regression analyses performed by adjusting for each available covariate one at a time (all P≤0.02). Pre-PCI IMR ≥27 U had 80.0% sensitivity and 85.0% specificity for predicting periprocedural MI (C statistic, 0.80; P=0.003). Pre-PCI IMR ≥27 U was independently associated with a 23-fold risk of developing periprocedural MI (odds ratio, 22.7; 95% CI, 3.8-133.9).

CONCLUSIONS

These data suggest that the status of the coronary microcirculation plays a role in determining susceptibility toward periprocedural MI at the time of elective PCI. The IMR can predict subsequent risk of developing myocardial necrosis and may guide adjunctive prevention strategies.

Risk factors of cardiac troponin T elevation in patients with stable coronary artery disease after elective coronary drug-eluting stent implantation

BACKGROUND

Cardiac troponin T elevation after coronary intervention has been demonstrated to be associated with the prognosis of coronary artery disease (CAD). However, there were few studies about comprehensive risk factors analysis of troponin T elevation after elective drug-eluting stent (DES) implantation.

HYPOTHESIS

The prognosis of CAD after coronary interventions was associated with clinical and procedural risk factors of CAD, such as age, hypertension, severity extent of CAD and so on.

METHODS

From March to December in 2010, patients with stable CAD were admitted for elective coronary intervention in our hospital. They were divided into an elevated troponin T group and a normal troponin T group by postprocedural troponin T. Clinical factors, laboratory-test factors, and angiographic factors (such as gender, age, cholesterol, Gensini score, and others) were analyzed.

RESULTS

A total of 209 patients with an average age of 64.0 ± 9.9 years were enrolled in the study: 70 patients with elevated troponin T (≥0.03 ng/mL) after DES implantation and 139 patients with normal troponin T (<0.03 ng/mL). After univariate analysis, we found that age, hypertension, total cholesterol, low density lipoprotein-cholesterol (LDL-C), Gensini score, number of stenosed vessels, and total implanted stents were associated with postprocedural troponin T elevation. According to the results of multivariate analysis, we found that age, total cholesterol, number of stenosed vessels, and number of implanted stents were independent risk factors of postprocedural troponin T elevation.

CONCLUSIONS

Age, serum total cholesterol, number of stenosed vessels, and number of implanted stents could be independent risk factors of troponin T elevation after elective DES implantation.

Periprocedural creatine kinase-MB elevations: long-term impact and clinical implications

Since the introduction of percutaneous transluminal coronary angioplasty (PTCA), percutaneous intervention with balloon catheters, stents, and atherectomy devices has become a widely accepted practice. The persistent complication of non-Q-wave myocardial infarction (MI), as evidenced by increased cardiac enzyme levels after intervention, has aroused only moderate concern because its incidence was perceived to be small and not clinically relevant. With more systematic assessments of cardiac enzymes--specifically, creatine kinase (CK) and its MB isoform--evidence has begun to clarify both the incidence and the prognosis of periprocedural non-Q-wave MI: It appears to occur nearly three times more often than is clinically evident across all device types (8 to 9% of all interventions) and is directly and continuously associated with adverse outcomes, including late death. Although directional and rotational atherectomy improve angiographic outcome compared with PTCA, periprocedural infarction occurs at least twice as often with these newer technologies; the incidence associated with stent placement is comparable to and possibly higher than that of PTCA. Factors that may cause elevated CK-MB levels include distal embolization, side branch occlusion, thrombus, and coronary spasm. Analyses of the major trials of platelet glycoprotein (GP) IIb/IIIa receptor inhibitors, a class of potent antiplatelet agents, show striking effectiveness of these drugs in reducing the incidence of "enzyme-only" or "silent" MI and in improving long-term clinical outcomes. The findings implicate platelet mediation in the occurrence of periprocedural infarction and suggest an important role for antiplatelet therapy, particularly GP IIb/IIIa receptor inhibition, in protecting patients undergoing percutaneous intervention.

Troponin ratio and risk stratification in subjects with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND

Cardiac enzyme release after percutaneous coronary intervention (PCI) seems to play a role in risk stratification. After PCI, CK-MB plasmatic concentrations three times above the upper level of normal (ULN) are currently the most used risk stratification parameters. We sought to assess whether peak cardiac troponin I (cTn-I) concentration/base concentration ratio (PBTR) may act as a predictor of major adverse cardiac events (MACEs) after PCI, regardless of cTn-I ULN.

METHODS

We evaluated 326 consecutive patients with acute coronary syndrome (ACS) who underwent PCI. Baseline and post-PCI cTn-I values were evaluated over serial blood samples every 6h for at least 72h. Patients were further divided into four groups according to their PBTR values (<1, 1-4, 4-10, >10). MACEs were recorded over a 6-month follow-up period. Patients with primary PCI or unsuccessful PCI were excluded from the study.

RESULTS

Higher values of PBTR significantly correlated with a worse prognosis at 6 months (<1, 16.30% of MACEs; 1-4, 19.42%; 4-10, 24.39%; >10, 35.63%; p<0.05), both in Q-wave myocardial infarction (MI) and unstable angina (UA) subgroups. The correlation remained statistically significant, even considering subjects with peak cTn-I less than three times the ULN (p < 0.05) and after correction for age, gender, risk factors, diagnosis (MI versus UA), and peak cTn-I levels in a multiple Cox' regression analysis (HR 1.62, p<0.05).

CONCLUSIONS

PBTR is an independent predictor of MACEs after PCI in a 6-month follow-up period. This risk stratification tool may be useful to predict adverse events in PCI patients, even in the case of apparently non-elevated peak cTn-I concentrations.

Evolution of anticoagulant and antiplatelet therapy: benefits and risks of contemporary pharmacologic agents and their implications for myonecrosis and bleeding in percutaneous coronary intervention

Periprocedural myonecrosis, as evidenced by elevated creatine kinase-myocardial bound (CK-MB) levels, occurs in up to 25% of patients undergoing percutaneous coronary intervention (PCI) and has been linked with an increased risk of adverse short- and long-term clinical outcomes. Such myonecrosis arises from three main pathophysiological mechanisms: procedure-related complications, lesion-specific characteristics (e.g., large thrombus burden, plaque volume), and patient-specific characteristics (e.g., genetic predisposition, arterial inflammation). Periprocedural myonecrosis has not been definitively identified as the cause of postprocedural ischemic events, although agents that reduce or prevent thrombosis--including aspirin, thienopyridines, heparin, low-molecular-weight heparins, glycoprotein IIb/IIIa inhibitors, and direct thrombin inhibitors--have been shown to reduce the incidence of ischemic outcomes in this population, as have agents that reduce inflammation (aspirin, statins). At the same time, antithrombotic agents are known to increase the risk of bleeding and the use of transfusions, which have likewise been associated with worse outcomes in these patients. Thus, optimal management of patients undergoing PCI represents a balance between minimizing the risk of ischemic outcomes and simultaneously minimizing the risk of major bleeding. It may be that patients who have only minor, untreated postprocedural elevations in CK-MB level (with no clinical or angiographic signs of ischemia) might have a better prognosis than patients who have normal CK-MB levels but who suffer major bleeding complications.

Measuring aspirin resistance, clopidogrel responsiveness, and postprocedural markers of myonecrosis in patients undergoing percutaneous coronary intervention

Aspirin and clopidogrel are proven to prevent thromboembolic events during percutaneous coronary intervention (PCI). Enzyme release of creatine kinase-MB (CK-MB) enzyme during PCI has been associated with an increased risk of future adverse cardiac events. This study examined the correlation between measurements of aspirin resistance and the level of inhibition of the thienopyridine-specific P2Y12 platelet receptor and CK-MB release after PCI. We prospectively studied 330 patients with elective PCI treated with drug-eluting stents. Patients were pretreated with aspirin and clopidogrel. Patients with positive CK-MB or acute coronary syndrome and those on glycoprotein IIb/IIIa inhibitors were excluded. Serum assays of aspirin resistance (Ultegra Rapid Platelet Function Assay-ASA, Accumetrics) and clopidogrel resistance (Rapid Platelet Function Assay P2Y12, Accumetrics) were performed before PCI. Serum troponinI and CK-MB levels were measured at 8, 16, and 24 hours after PCI. Aspirin resistance unit (ARU) measurement > or =550 was detected in 12 patients (3.7%). Mean platelet reactivity unit (PRU; measurement of inhibition of P2Y12 activity) was 192.2 +/- 95.4 (lower PRU, more inhibition of P2Y12 receptor). There was no correlation between level of ARU or PRU and troponin I or CK-MB release after PCI at any time point. Only multivessel coronary disease was found to be a predictor of any increase in CK-MB in a multivariate analysis (odds ratio 2.2, 95% confidence interval 1.4 to 3.3, p = 0.0003). A positive correlation was found between levels of ARU and PRU. Target vessel revascularization/major adverse cardiac event rate at 6 months was 8.2% with no correlation between ARU or PRU and release of cardiac enzymes or occurrence of adverse cardiac events. In conclusion, this study does not support routine measurements of aspirin and clopidogrel resistance in stable patients undergoing PCI.

Angiographic adverse events during percutaneous coronary intervention fail to predict creatine kinase-MB elevation

We attempted to determine if aggressive detection of angiographic adverse events during coronary intervention could predict subsequent creatine kinase (CK)-MB elevations. During coronary intervention, both fluoroscopy and cine angiography were used to detect angiographic adverse events. At least one angiographic adverse event occurred in 133/251 (53%) of procedures. CK-MB elevation occurred in 24% of procedures. Slow flow during the procedure (P=0.002) and chest discomfort at the end of the procedure (P=0.007) were the strongest predictors of CK-MB elevation. Among procedures with no angiographic adverse events, CK-MB elevation occurred in 15/121 (12%), accounting for 25% of CK-MB elevations. We conclude that CK-MB elevation occurs after angiographically uncomplicated coronary interventions even when angiographic adverse events are aggressively detected. Routine monitoring of cardiac enzymes is necessary to detect all patients who will experience myocardial injury after coronary intervention.

Angiographic adverse events, creatine kinase-MB elevation, and ischemic end points complicating percutaneous coronary intervention (a REPLACE-2 substudy)

Several angiographic adverse events during coronary balloon angioplasty have been associated with increased creatine kinase-MB (CK-MB) enzymes and adverse clinical outcomes. The significance of angiographic adverse events in the stent era has not been widely studied. We analyzed 10 types of angiographic adverse events that were reported in the 6,010-patient Second Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events (REPLACE-2) trial to determine their relation to CK-MB elevation and clinical ischemic end points after percutaneous coronary intervention (PCI). Angiographic adverse events occurred in 9.1% of REPLACE-2 patients. Most (8 of 10) types of angiographic adverse events were associated with an increased risk of increased CK-MB (p <0.001 for each), and 47% of all patients with an angiographic adverse event developed increased CK-MB. Logistic regression analysis showed that the strongest predictor of death, myocardial infarction, or revascularization at 6 months was the occurrence of an angiographic adverse event during PCI (odds ratio 1.9, 95% confidence interval 1.6 to 2.4, p <0.001). Side branch closure, abrupt closure, any decreased flow during the procedure, angiographic distal embolization, and perforation or tamponade were individual predictors of the occurrence of the combined clinical ischemic end point at 6-month follow-up (p <0.005 for each). In conclusion, most angiographic adverse events during PCI are associated with increased CK-MB and are powerful predictors of adverse clinical events within 6 months.

Preprocedural statin use is associated with a reduced hazard of postprocedural myonecrosis in patients undergoing rotational atherectomy--a propensity-adjusted analysis

Incidence of myonecrosis in patients undergoing rotational atherectomy was evaluated by preprocedural statin use. The incidence of any myonecrosis (24.1% vs 52.3%, P < .001) or significant myonecrosis (7.5% vs 21.8%, P < .001) was significantly lower among patients pretreated with statins. This difference remained significant after multivariable and propensity adjustment.

Baseline troponin level: key to understanding the importance of post-PCI troponin elevations

AIMS

The adverse prognostic significance of biomarker elevations after percutaneous coronary intervention (PCI) is well established. However, often baseline troponin values are not included in the analysis or sensitive criteria are not employed. Accordingly, we assessed the timing and magnitude of post-PCI troponin T (cTnT) levels and their relationships to outcomes in patients with and without pre-PCI baseline cTnT elevations using a sensitive assay and sensitive cut-off values.

METHODS AND RESULTS

cTnT was measured at baseline (pre-PCI), 8 and 16 h post-PCI in 2352 patients. A cTnT elevation was defined as > or =0.03 ng/mL. No baseline cTnT elevations were detected in 1619 patients undergoing mostly (97%) non-urgent procedures (cTnT = 0.01 +/- 0.002 ng/mL; mean +/- SD). 733 patients had baseline cTnT elevations. Only the baseline troponin value had prognostic importance. Patients with elevated cTnT baseline levels had a higher overall cumulative 12-month death/MI rate of 11.1% compared with those without elevated baseline levels of 4.7% (P < 0.05). Neither the timing nor the magnitude of the post-procedure cTnT elevations was predictive of long-term death/MI rates when baseline elevations were included in the analysis. Similar findings were observed for baseline creatine kinase-MB (CK-MB) levels. Late increases in cTnT levels (16 h post-PCI) presaged in-hospital events only.

CONCLUSION

Long-term prognosis is most often related to the baseline pre-PCI troponin value and not the biomarker response to the PCI. These results support a re-evaluation of the use of biomarker data in relation to PCI.

Prediction of complications following nonemergency percutaneous coronary interventions

Previous models for prediction of complications after percutaneous coronary interventions (PCIs) have included in-hospital mortality and major in-hospital complications. In general, these models have excluded elevated cardiac biomarkers as a complication. We sought to determine whether a risk model could predict complications, including biomarker elevation, in patients undergoing nonemergency PCI. We examined the outcomes of nonemergency PCI performed on patients at Mayo Clinic from 2000 to 2003. The primary end point was in-hospital complications of death, myocardial infarction (MI) (Q-wave MI, or post-PCI creatine kinase-MB elevation >or=3 times the upper limit of normal), emergency coronary artery bypass grafting, or stroke. We used the Hosmer-Lemeshow test to demonstrate the adequacy of the model fit, and the c-index for discriminatory ability of the model. Of 2,894 nonemergency PCIs, the end point was noted in 232 (8%). The final prediction model included vein graft intervention (odds ratio [OR] 2.19), angiographic thrombus (OR 2.12), preprocedure stenosis of a minor (OR 1.98) or major (OR 1.62) side branch, and type C lesion (OR 1.48). The model had modest ability to discriminate between event and nonevent patients (c = 0.641). In the 500 bootstrap samples for internal validation, the c-index was 0.642 +/- 0.020, indicating only fair discriminatory ability. The average number of observed events was 232.0 +/- 14.7 compared with 232.1 +/- 2.5 expected events (average difference -0.06 +/- 14.5). In conclusion, the 5 risk variables associated with an increased risk of complications in patients undergoing elective PCI included vein graft intervention, presence of angiographic thrombus, stenosis of a major or minor side branch, and type C lesion; however, the discriminatory ability of the model derived from the variables was only modest.

Peri-procedural myocardial injury: 2005 update

During the past three decades, percutaneous coronary intervention has become one of the cardinal treatment strategies for stenotic coronary artery disease. Technical advances, including the introduction of new devices such as stents, have expanded the interventional capabilities of balloon angioplasty. At the same time, there has been a decline in the rate of major adverse cardiac events, including Q-wave acute myocardial infarction, emergency coronary artery bypass grafting, and cardiac death. Despite these advances, the incidence of post-procedural cardiac marker elevation has not substantially decreased since the first serial assessment 20 years ago. As of now, these post-procedural cardiac marker elevations are considered to represent peri-procedural myocardial injury (PMI) with worse long-term outcome potential. Recent progress has been made for the identification of two main PMI patterns, one near the intervention site (proximal type, PMI type I) and one in the distal perfusion territory of the treated coronary artery (distal type, PMI type II) as well as for preventive strategies. Integrating these new developments into the wealth of clinical information on this topic, this review aims at giving a current perspective on the entity of PMI.

Cardiac Preconditioning during Percutaneous Coronary Interventions

Ischemic preconditioning (PC) is a polygenic defensive cellular adaptive phenomenon of the heart to ischemic stress, whereby the heart changes its phenotype to become more resistant to subsequent ischemia. Early and late of PC represent two chronologically and pathophysiologically distinct phases of this phenomenon, which can be recruited pharmacologically. We represent a post hoc analysis examining the late PC-mimetic effects of nitroglycerin (NTG) on peri-procedural myocardial necrosis during percutaneous coronary intervention (PCI). A group of 66 patients presenting with angina were randomized, 24 h prior to a scheduled PCI for single obstructive CAD, to a 4 h pretreatment with intravenous NTG or saline. Measurements of electrocardiographic ST-segment shifts, echocardiographic regional wall motion and angina scores demonstrated that NTG pre-treatment preconditioned the heart by rendering it resistant to ischemia during balloon inflations. NTG-pretreated patients exhibited trends towards lower average peak CK (131.1 vs. 188.6 U/L, P = 0.38) and CK-MB levels (7.1 vs. 12.6 ng/ml, P = 0.40). NTG, however, had no significant impact on the incidence of post-procedural MI or any cardiac enzyme elevation. The exploitation of ischemic and pharmacological PC may prove a useful strategy to confer cardioprotection during high-risk PCI and is worth exploring.

GuardWire emboli protection device is associated with improved myocardial perfusion grade in saphenous vein graft intervention

BACKGROUND

Use of emboli protection devices (EPD) during saphenous vein graft percutaneous coronary intervention (SVG-PCI) has been proven to reduce major adverse cardiac events (MACE). However, the impact of EPD on the microcirculation using Thrombolysis in Myocardial Infarction myocardial perfusion grade (TMP) has not been fully characterized. We sought to analyze TMP after SVG-PCI with and without EPD and determine its impact on inhospital MACE.

METHODS

From August 2001 to December 2002, 305 patients had SVG-PCI suitable for EPD; 210 (69%) had an angiogram appropriate for TMP evaluation. Of those, 46 (22%) had an EPD (GuardWire, Medtronic, Minneapolis, Minn) deployed during the coronary intervention. Both groups were similar with regard to most demographic and clinical features.

RESULTS

A TMP score of 2.5 or 3 was obtained in 98% of the EPD group versus 85% of the unprotected SVG-PCI (P = .01). There was a trend towards reduction in MACE when using EPD (15% vs 27%, respectively, P = .07). Peak postprocedural creatine kinase-MB was somewhat lower in the EPD group (6.03 +/- 7.8 ng/mL vs 14.87 +/- 42 ng/mL, P = .17) Patients with a TMP grade of 2.5 or 3 had a statistically significant reduction in MACE (OR 0.36, 95% CI 0.14-0.87, P = .02).

CONCLUSIONS

Compared with SVG-PCI without emboli protection, EPD significantly improved TMP and trended towards a reduction in MACE.

MR imaging in ischemic heart disease

This article reviews the current MR imaging literature with respect to ischemic heart disease and focuses on the clinical practicalities of cardiac MR imaging today.

Predictors of troponin elevation after percutaneous coronary intervention

The predictors of troponin release after percutaneous coronary intervention were prospectively assessed in 405 consecutive patients. Troponin release occurred frequently (27%) and was associated with complications during the procedure, including sapheneous vein graft interventions, multistent use, glycoprotein IIb/IIIa use, and a history of hypercholesterolemia.

Glycoprotein IIb/IIIa receptor antagonists: a comparative review of their use in percutaneous coronary intervention

Antiplatelet therapy is critical during percutaneous coronary intervention (PCI) as it reduces the incidence of abrupt closure and distal thrombi embolization, which are significant acute peri-procedural complications likely responsible for the clinical adverse outcomes with PCI, namely death, myocardial infarction or urgent target vessel revascularization. Glycoprotein (GP) IIb/IIIa receptor antagonists, potent antiplatelet agents, have been specifically tested during PCI. There are currently three commercially available GP IIb/IIIa receptor antagonists and results from more than ten randomized clinical PCI trials have established their clinical efficacy and tolerability during coronary intervention. There remain questions regarding variability in efficacy among individual clinical trials and among population subsets, potential clinical differences among the available agents, and their optimal use. This article will critically review the body of evidence for clinical efficacy and tolerability of each individual tested compound, highlight potential differences among agents, and raise important issues involving their use in clinical practice.

Timing of Peak Troponin T and Creatine Kinase-MB Elevations After Percutaneous Coronary Intervention

STUDY OBJECTIVE

The prognostic significance of elevations in creatine kinase-MB and troponin T (cTnT), which have been conventionally measured 6 to 8 h after percutaneous coronary intervention (PCI), has been established. However, the time to peak biomarker appearance in the circulation has not been defined and is the purpose of this pilot study.

DESIGN

Nonrandomized, nonconsecutive patient cohort.

SETTING

Clinical practice, Mayo Clinic, Rochester, MN.

PATIENTS

Cohort (n = 57) undergoing elective PCI.

INTERVENTIONS

cTnT and creatine kinase (CK)-MB measured at baseline, 2 h, 4 h, 8 h, and > or = 2 h (mean +/- SEM, 18 +/- 5 h) after PCI.

MEASUREMENTS AND RESULTS

Postprocedure cTnT elevations were detected in 30 of 57 patients (53%). Of these, 4 of 30 patients (13%) had peak cTnT at 4 h (0.80 +/- 0.40 ng/mL), 5 of 30 patients (17%) had peak cTnT at 8 h (1.07 +/- 0.48 ng/mL), and 21 of 30 patients (70%) had peak cTnT at > or = 12 h (0.21 +/- 0.06 ng/mL); 22 of 30 patients received abciximab. Elevations in CK-MB occurred in 14 of 57 patients (25%). Of these, 3 of 14 patients (21%) demonstrated peak CK-MB at 2 h (18.5 +/- 7.9 ng/mL) and the remainder (11 of 14 patients, 79%) during the 12- to 20-h interval (20.2 +/- 4.4 ng/mL); 12 of 14 patients received abciximab.

CONCLUSION

More cTnT than CK-MB elevations occur after PCI; however, both biomarkers demonstrate a longer time to peak value than anticipated in clinical practice. Early surveillance monitoring (< 12 h) does not detect peak biomarker levels, especially in patients with normal baseline values. If peak levels are to be used to determine prognosis, then longer time intervals should be used for post-PCI surveillance. The timing of peak elevations appears to be influenced by baselines values as well. Early elevations may reflect the conjoint effects of injury associated with the disease process and the intervention itself. These data suggest that a re-evaluation of surveillance monitoring to account for the variability reported and the influence of baseline elevations of biomarkers may improve the prognostic power of the measurements.

Increased CK-MB release is a “trade-off” for optimal stent implantation

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 5x 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.

Mortality risk conferred by small elevations of creatine kinase-MB isoenzyme after percutaneous coronary intervention

OBJECTIVES

The aim of this study was to assess whether small creatine kinase-MB isoenzyme (CK-MB) elevations after percutaneous coronary intervention (PCI) affect the subsequent mortality risk.

BACKGROUND

Several studies have evaluated the relationship of CK-MB levels after PCI with the subsequent risk of death. While there is consensus that elevations exceeding 5 times the upper limit of normal increase mortality significantly, there is uncertainty about the exact clinical impact of smaller CK-MB elevations.

METHODS

We performed a meta-analysis of seven studies with CK-MB measurements and survival outcomes on 23230 subjects who underwent PCI. Data were combined with random effects models.

RESULTS

Mean follow-up was 6 to 34 months per study. By random effects, 19% (95% confidence interval [CI], 16% to 23%) had one- to five-fold CK-MB elevations, while only 6% (95% CI, 5% to 9%) had >5-fold elevations. Compared with subjects with normal CK-MB, there was a dose-response relationship with relative risks for death being 1.5 (95% CI, 1.2 to 1.8, no between-study heterogeneity) with one- to three-fold CK-MB elevations, 1.8 (95% CI, 1.4 to 2.4, no between-study heterogeneity) with three- to five-fold CK-MB elevations, and 3.1 (95% CI, 2.3 to 4.2, borderline between-study heterogeneity) with over five-fold CK-MB elevations (p < 0.001 for all).

CONCLUSIONS

Any increase in CK-MB after PCI is associated with a small, but statistically and clinically significant, increase in the subsequent risk of death.

Distal myocardial protection during percutaneous coronary intervention with an intracoronary beta-blocker

BACKGROUND

Experimental studies have demonstrated that intravenous beta-blocker administration before coronary artery occlusion significantly reduces myocardial injury. Clinical studies have shown that intracoronary (IC) propranolol administration before percutaneous coronary intervention (PCI) delays myocardial ischemia. The present study tested the hypothesis that IC propranolol treatment protects ischemic myocardium from myocardial damage and reduces the incidence of myocardial infarction (MI) and short-term adverse outcomes after PCI.

METHODS AND RESULTS

Patients undergoing PCI (n=150) were randomly assigned in a double-blind fashion to receive IC propranolol (n=75) or placebo (n=75). Study drug was delivered before first balloon inflation via an intracoronary catheter with the tip distal to the coronary lesion. Biochemical markers were evaluated through the first 24 hours and clinical outcomes to 30 days. Evidence of MI with creatine kinase-MB elevation after PCI was seen in 36% of placebo and 17% of propranolol patients (P=0.01). Troponin T elevation was seen in 33% of placebo and 13% of propranolol patients (P=0.005). At 30 days, the composite end point of death, postprocedural MI, non-Q-wave MI after PCI hospitalization, or urgent target-lesion revascularization occurred in 40% of placebo versus 18% of propranolol patients (hazard ratio 2.14, 95% CI 1.24 to 3.71, P=0.004).

CONCLUSIONS

IC administration of propranolol protects the myocardium during PCI, significantly reducing the incidence of MI and improving short-term clinical outcomes.

Prognostic implication of creatine kinase release after elective percutaneous coronary intervention in the pre-IIb/IIIa antagonist era

BACKGROUND

The significance of mild elevations in cardiac enzymes after an elective percutaneous coronary intervention (PCI) still remains controversial. We evaluated the significance of creatine phosphokinase level (CPK) elevations in a large cohort of patients who had undergone an elective PCI before the IIb/IIIa receptor antagonist era.

METHODS

All patients enrolled in the Emory databank from 1981 to 1996 who had an elective PCI were evaluated. We identified 15,637 patients who met our inclusion and exclusion criteria. Patients were divided into 4 groups on the basis of the magnitude of the CPK elevation noted in the post-PCI period: group I (CPK <250 mg/dL, n = 14,512); group II (CPK 250-500 mg/dL, n = 715); group III (CPK 500-750 mg/dL, n = 164); and group IV (CPK >750 mg/dL, n = 246).

RESULTS

CPK elevations were associated with a significant increase in the periprocedure angiographic complications. Angiographic complication rates were 14.6%, 30.5%, 40.2%, and 43.5% in groups I, II, III, and IV, respectively (P <.001). Long-term survival also correlated inversely with the magnitude of CPK elevations. The 10-year survival rates were 73%, 71%, 69%, and 55% in groups I, II, III, and IV, respectively (P <.0001). After multivariate analysis to correct for clinical factors, a CPK elevation of at least 3-times normal (group IV) was found to be an independent predictor of diminished 30-day and long-term survival (hazard ratio 1.84, 95% CI 1.41-2.41, P <.0001). Elevations in CPK <3-times normal (groups II and III) were not independently predictive of poor long-term survival.

CONCLUSION

A CPK level >3-times normal after an elective PCI is a strong independent predictor of poor long-term prognosis.

Association between CK-MB elevation after percutaneous or surgical revascularization and three-year mortality

OBJECTIVES

The goal of this study was to assess the long-term impact of creatine kinase-MB isoform (CK-MB) elevation after percutaneous or surgical revascularization.

BACKGROUND

The long-term impact of CK-MB elevation after coronary artery bypass grafting (CABG) is not as well characterized as that following percutaneous coronary intervention (PCI).

METHODS

The three-year cumulative survival of consecutive patients who underwent their first percutaneous or surgical revascularization procedure between January 1, 1995 and August 31, 2000 and had CK-MB determination was assessed using the Social Security Death Index.

RESULTS

The 3,812 patients undergoing CABG had a less favorable coronary risk profile than the 3,573 patients undergoing PCI. The incidence of CK-MB elevation above normal range was 90% and 38% for the CABG and PCI groups (p < 0.001). In 6% and 5%, respectively, the elevation surpassed 10x the upper limit of normal (ULN). At an average follow-up of three years, there were 712 deaths, 83 of which occurred within 30 days of procedure. The cumulative survival was 92% and 90% for CABG and PCI, respectively (p = 0.003). Chronic renal insufficiency (adjusted hazard ratio [HR] 3.8, [95% confidence interval 3.1 to 4.6]), age (HR 1.5 per decade [1.3 to 1.6]), ejection fraction <40% (HR 1.3 [1.1 to 1.5] and PCI (HR 1.6 [1.3 to 1.9]) were the main predictors of increased mortality. Creatine kinase-MB isoform elevation only above 10 x ULN was independently predictive of mortality in the CABG (HR 1.3 [1.1 to 1.5]) and PCI (HR 1.1 [1.0 to 1.2]) groups, p < 0.001.

CONCLUSIONS

Creatine kinase MB isoform elevation after revascularization is very common, particularly in CABG patients. When extensive, it is independently correlated with increased mortality over a three-year period. Identification and aggressive management of patients with high levels of CK-MB after revascularization may improve their outcome.

Initial clinical experience with distal protection using the FilterWire in patients undergoing coronary artery and saphenous vein graft percutaneous intervention

Percutaneous coronary intervention (PCI) of saphenous vein grafts (SVG) and native coronary arteries may be associated with embolization of particulate debris into the distal microcirculation. The FilterWire uses a polyurethane filter bag contained on a radiopaque loop to trap embolic debris during native vessel and SVG intervention. The objectives of this study were to assess the feasibility and safety of the FilterWire during PCI and to examine the size and content of the particulate debris captured during SVG and native vessel intervention. Early angiographic, in-hospital, and 30-day clinical outcomes were reviewed in 35 patients with 36 lesions treated with the FilterWire during PCI. Lesions were located in 22 (61%) native coronary arteries and in 14 (39%) SVGs. Multivessel coronary artery disease was present in 75% of patients. Lesions were complex (ACC/AHA complexity B2 or C) in 81% of cases. The FilterWire was successfully delivered and deployed distal to the site of coronary intervention in 92% of lesions, including 95% of native vessels and 82% of SVG lesions. Embolic debris was entrapped in 82% of these cases. The average particulate debris had a mean major axis of 490 microm (range, 45-3,302 microm) and minor axis of 226 microm (range, 33-1,677 microm). Although reduced flow was common (36.1%) when the FilterWire was in place, there were no sustained episodes of abrupt closure and only one (2.8%) patient developed sustained no-reflow after FilterWire removal. Distal branch vessel embolization was found in four (11.1%) cases. Major adverse cardiac events occurred in 5 (14%) of 35 patients treated with the device, although 2 of these patients were evolving an acute myocardial infarction at the time of the procedure; in patients meeting the prospectively defined inclusion criteria, the major adverse cardiac event was 6%. These results suggest that the FilterWire is a feasible and safe method of collecting particulate debris released during SVG and native vessel coronary intervention. Its benefit over conventional therapy and other distal protection devices is currently under study.

Diagnosis of myocardial injury by biochemical markers: problems and promises

The role of biochemical markers in the diagnosis of acute coronary syndromes has increased considerably in the past decade. The World Health Organization previously defined acute myocardial infarction as a combination of at least 2 of 3 components: symptoms consistent with acute myocardial infarction, electrocardiogram changes diagnostic of acute myocardial infarction, and an enzyme pattern with classic rise and fall. Measurement of creatine kinase and its MB fraction by various assays was the gold standard for the diagnosis. Troponins are more specific and sensitive markers for myocardial injury, and their increasing utilization has resulted in a broadening of the definition of acute myocardial infarction to incorporate high-risk acute coronary syndromes. Previously, traditional enzyme evaluation left patients with small amounts of cellular death undiagnosed; these patients were categorized as having unstable angina or, worse, noncardiac chest pain. Newer markers now identify these patients as a subgroup at high risk for cardiac death or cardiac events. Newer therapeutic interventions and a more invasive strategy have been shown to improve outcomes in this high-risk subgroup. Increased specificity has also reduced the number of patients who undergo extensive, expensive, and invasive evaluations for noncardiac syndromes due to false elevations of traditional markers. This article comprehensively reviews the evolution of biochemical markers for the diagnosis of acute myocardial infarction, addressing their promise for improving delivery of care and outcomes and their technical and diagnostic pitfalls.

Embolization in atherosclerosis

Much has been learned about microembolization in the last two decades. The promising blood markers for brain injury will further enhance our future understanding of microembolic events. New surgical techniques, drugs, and devices have substantially reduced microembolization during carotid angioplasty, CEA, and CABG.

Clinical outcomes of compromised side branch (stent jail) after coronary stenting with the NIR stent

Acute side-branch (SB) compromise or occlusion stent jail after native coronary stenting is a matter of concern. Attempts at maintaining SB patency can be a technical challenge. The purpose of this study was to determine the clinical impact of SB compromise or occlusion in patients undergoing stenting of parent vessel lesions. We evaluated in-hospital and long-term clinical outcomes (death, Q-wave myocardial infarction, and repeat revascularization rates at 6 months) in 318 consecutive patients undergoing NIR stent implantation across an SB. Based on independent angiographic analysis, 218 (68.6%) patients had no poststent SB compromise, 85 (26.7%) patients had narrowed SB (> 70% narrowing, without total occlusion), and 15 (4.7%) patients had an occluded SB after stent implantation. The baseline patient and lesion characteristics were similar between the groups. Procedural success was 100%. Patients with SB occlusion had a higher stents/lesion ratio (P < 0.006). Side-branch occlusion was associated with higher in-hospital ischemic complications (Q-wave myocardial infarction, 7%; non-Q-wave myocardial infarction, 20%; P < 0.05) compared to patients with SB compromise or normal SB. At 6-month follow-up, there was a trend for more myocardial infarctions in the group with SB occlusion during the index procedure (Q-wave myocardial infarction, 7% vs. 1% in the narrowed and 0% in normal SB; P = 0.09). However, late target lesion revascularization and mortality were similar in the three groups (P = 0.91). SB occlusion after parent vessel stenting is associated with more frequent in-hospital Q-wave and non-Q-wave myocardial infarctions. However, with the NIR stent, side-branch compromise or occlusion does not influence late (6 month) major adverse events, including death, myocardial infarction, or need for repeat revascularization.

Direct coronary stenting: effect on coronary blood flow, immediate and late clinical results

Direct stenting (DS) was attempted in 99 coronary lesions in 94 patients while standard stenting (SS) was attempted in 113 lesions in 103 patients matched for clinical characteristics, stenosis type, and location and stent type. The angiographic result was also evaluated according to TIMI frame count method (TFC) before and after procedure. A clinical follow-up was performed 1 year after the procedure. Before the procedure, TIMI grade 3 flow was detected in 42 cases (42.4%), grade 2 in 40 cases (40.4%), grade 1 in 5 cases (5.1%), and grade 0 in 12 cases (12.1%) in the DS group; these data were similar in SS group. After the procedure, TIMI grade flow was 3 in 90 cases (92.8%) in DS group and in 87 (77.0%) in SS group (P < 0.005); grade 2 was observed in 7 case (7.2%) in DS group and in 25 (22.1%) in SS group (P < 0.005). Major adverse cardiac events during hospitalization and at follow-up were similar in two groups. Radiation exposure time and procedure costs per lesion were significantly reduced in DS group compared to SS group (10.1 +/- 8 min vs. 13.9 +/- 4.7 min, P < 0.001; and 1901 +/- 687 Euro vs. 2352 +/- 743 Euro, P < 0.001, respectively). This study confirms that, in selected patients, direct stenting is a safe and successful procedure, allowing a significant reduction in radiation exposure time and procedural costs compared to standard stenting technique. The angiographic success is confirmed by the improvement in TFC in all cases.

Effect of abciximab on cardiac enzyme elevation after transluminal extraction atherectomy (TEC) in high-risk saphenous vein graft lesions: comparison with a historical control group

Saphenous vein graft (SVG) intervention has been associated with an increased incidence of distal embolization. Long lesions and lesions associated with thrombus are particularly at increased risk. This study was performed to determine whether abciximab may decrease this risk in high risk SVG angioplasty. From June 1994 to June 1998, 84 patients with at least one high risk factor, i.e., lesion length >20 mm or angiographic evidence of thrombus, underwent Transluminal extraction atherectomy (TEC) procedure followed by balloon dilatation or stenting. Of these 84 patients, 37 who had procedure after September 1995 underwent TEC with abciximab (Abciximab Group) and 47 who had their procedure before that date had TEC without abciximab thereby serving as historic control (Non-Abciximab Group). All patients had normal pre-procedure CK and CK-MB. Total creatine kinase (CK) and CK-MB were measured every 8 hr post-procedure for 24 hr. Baseline demographics, angiographic characteristics, incidence of LV dysfunction and triple vessel disease were similar between the two groups. Graft age was similar between two groups (122 +/- 70 vs. 117 +/- 54 months). Graft diameter, pre and post-procedure percent stenoses were not different between the two groups. Stents were used in 65% in the Abciximab group and 45% in Non-Abciximab group (P = 0. 14). There was no in-hospital repeat PTCA, urgent bypass surgery, or cardiac death. There was no difference between the two groups in regards to the incidence of any elevation of total CK (27% vs. 21. 3%) or CK-MB (54% vs. 51%). When used in conjunction with TEC in treating high risk vein graft lesions, abciximab did not reduce post procedure CK-MB elevation in this patient population.

Relation between coronary atherosclerotic plaque burden and cardiac enzyme elevation following percutaneous coronary intervention

Several studies have reported that elevation of cardiac creatine kinase (CK) enzymes after percutaneous coronary intervention (PCI) is associated with an increase in cardiac morbidity and mortality during follow-up. However, it remains unclear if enzyme elevation contributes to the adverse outcomes or is simply a marker for adverse events. We conducted a case-control study to determine if angiographically determined atherosclerotic plaque burden correlated with CK elevation. Patients (cases, n = 23) with CK elevation after PCI were identified along with 46 age- and gender-matched controls without CK elevation. Detailed angiographic analysis quantified the percentage of coronary artery length with any luminal irregularity, a surrogate for plaque burden. The CK elevation group was characterized by a greater number of smokers (65% vs 33%, p = 0.02), more thrombus-containing lesions (22% vs 2.2%, p = 0.014), and more frequent abrupt closure (13% vs 0%, p = 0.03). In addition, the case group had a 50% increase in atherosclerotic plaque burden compared with controls (30 +/- 14% vs 20 +/- 14%, p = 0.006). These data suggest that CK elevation after PCI is a marker for more extensive atherosclerosis, which may explain the worse prognosis of these patients.

Pronounced benefit of coronary stenting and adjunctive platelet glycoprotein IIb/IIIa inhibition in complex atherosclerotic lesions

BACKGROUND

Previous trials testing stents compared with balloon angioplasty excluded patients with complex lesions and did not assess the effect of adjunctive platelet IIb/IIIa inhibition. This analysis sought to assess the effect of stenting and abciximab specifically for patients with complex lesions.

METHODS AND RESULTS

Patients with complex lesions (long, tandem, severely calcified, restenotic, thrombotic, or ostial; total occlusions; bifurcations; saphenous vein grafts; and multivessel interventions) from the Evaluation of PTCA to Improve Long-Term Outcome by c7E3 GP IIb/IIIa Receptor Blockade (EPILOG) and the Evaluation of Platelet IIb/IIIa Inhibitor for Stenting (EPISTENT) trials were included in the analysis. The 1-year combined death or myocardial infarction rates in the 4 treatment groups were as follows: balloon angioplasty/placebo, 14.2%; stent/placebo, 15.8%; balloon angioplasty/abciximab, 7.6%; and stent/abciximab, 8.0% (P<0.001). Death rates were 3.2%, 3.1%, 2.1%, and 0.5%, respectively (P=0.03). The incidence of target vessel revascularization at 1 year was 30.5%, 18.0%, 24.4%, and 19.7% in the 4 groups, respectively (P<0.001). After adjustment for baseline differences, multivariate analysis demonstrated that the rate of death or myocardial infarction was independently reduced by balloon angioplasty/abciximab (hazard ratio, 0.51; P<0.001) and stent/abciximab (hazard ratio, 0.60; P=0.02) but was not affected by the use of stents alone. Conversely, target vessel revascularization was reduced by stent/placebo (hazard ratio, 0.53; P<0.001), stent/abciximab (hazard ratio, 0.58; P<0.001), and balloon angioplasty/abciximab (hazard ratio, 0.74; P=0.006) compared with balloon angioplasty/placebo, respectively.

CONCLUSIONS

The combination of stenting and abciximab during percutaneous coronary interventions for patients with angiographically complex lesions confers additive long-term benefit with respect to death, myocardial infarction, and target vessel revascularization.

Glycoprotein Ia gene C807T polymorphism and risk for major adverse cardiac events within the first 30 days after coronary artery stenting

The glycoprotein complex Ia/IIa (GP Ia/IIa) is a major collagen receptor on platelets and other cell types. Recently, linked polymorphisms within the coding region of the GP Ia gene (C807T and G873A) were identified that are related to GP Ia/IIa surface expression. The T807/A873 allele is associated with high expression, whereas the C807/G873 allele is associated with low surface expression of GP Ia/IIa. Subsequently, the T807 allele was found to be associated with coronary and cerebral infarction in younger patients. Platelet adhesion to the vessel wall plays a pivotal role in thrombosis after coronary artery stent placement. The goal of this study was to test whether C807T polymorphism is associated with a higher incidence of thrombotic events following coronary stenting. Consecutive patients treated with coronary stent placement (n = 1797) were genotyped for C807T polymorphism with polymerase chain reaction and allele-specific fluorogenic probes. The composite end point was defined as death, myocardial infarction, or urgent target vessel revascularization within 30 days of stent implantation. The genotype distribution of the study population was CC in 36.5%, CT in 46.7%, and TT in 16.8% of the patients. The incidence of the composite end point was 6.5% in T allele carriers and 5.3% in noncarriers (odds ratio for T allele carriage 1.23 [95% confidence interval, 0.81-1.86],P = .33). After adjusting for other baseline characteristics, the odds ratio for the composite end point was 1.15 (0.76-1.75). Therefore, C807T genotype has no significant influence on the major adverse events occurring after coronary artery stenting.

Glycoprotein Ia gene C807T polymorphism and risk for major adverse cardiac events within the first 30 days after coronary artery stenting

The glycoprotein complex Ia/IIa (GP Ia/IIa) is a major collagen receptor on platelets and other cell types. Recently, linked polymorphisms within the coding region of the GP Ia gene (C807T and G873A) were identified that are related to GP Ia/IIa surface expression. The T807/A873 allele is associated with high expression, whereas the C807/G873 allele is associated with low surface expression of GP Ia/IIa. Subsequently, the T807 allele was found to be associated with coronary and cerebral infarction in younger patients. Platelet adhesion to the vessel wall plays a pivotal role in thrombosis after coronary artery stent placement. The goal of this study was to test whether C807T polymorphism is associated with a higher incidence of thrombotic events following coronary stenting. Consecutive patients treated with coronary stent placement (n = 1797) were genotyped for C807T polymorphism with polymerase chain reaction and allele-specific fluorogenic probes. The composite end point was defined as death, myocardial infarction, or urgent target vessel revascularization within 30 days of stent implantation. The genotype distribution of the study population was CC in 36.5%, CT in 46.7%, and TT in 16.8% of the patients. The incidence of the composite end point was 6.5% in T allele carriers and 5.3% in noncarriers (odds ratio for T allele carriage 1.23 [95% confidence interval, 0.81-1.86],P = .33). After adjusting for other baseline characteristics, the odds ratio for the composite end point was 1.15 (0.76-1.75). Therefore, C807T genotype has no significant influence on the major adverse events occurring after coronary artery stenting.

Long-term clinical events following creatine kinase--myocardial band isoenzyme elevation after successful coronary stenting

OBJECTIVE

We sought to evaluate the impact of intermediate creatine kinase-myocardial band isoenzyme (CK-MB) elevation on late clinical outcomes in patients undergoing successful stent implantation in native coronary arteries.

BACKGROUND

Elevations of CK-MB after percutaneous coronary interventions are frequent. An association between high level of CK-MB elevation (>5 times normal) and late mortality after balloon and new device angioplasty has been reported previously. However, significant controversy remains on the long-term clinical importance of lower CK-MB elevations (one to five times normal) after percutaneous coronary revascularization. Moreover, the incidence and prognostic importance of cardiac enzyme elevation after coronary stenting have not been well established.

METHODS

Prospectively collected data from 900 consecutive patients (1,213 lesions) undergoing successful stenting in native vessels were analyzed. Based on the CK-MB levels after coronary stenting, patients were classified into three groups: normal group 1 (n = 585), elevation of >1 to 5 times normal group 2 (n = 238) and elevation of >5 times normal group 3 (n = 77).

RESULTS

Patients in group 3 had more in-hospital recurrent ischemia (p = 0.001) and pulmonary edema (p = 0.01) than patients in groups 1 and 2. Long-term clinical end points were similar between groups 1 and 2. However, patients in group 3 had an increased incidence of late mortality compared with patients in groups 2 and 1 (6.9%, 1.2% and 1.7%, respectively, p = 0.01). Multivariate analysis showed that patients with CK-MB >5 times normal after coronary stenting had an increased risk of major adverse clinical events (relative risk: 1.70, p < 0.05) and death (relative risk: 3.25, p < 0.05) that was not observed in patients with lower CK-MB rise.

CONCLUSIONS

Patients with CK-MB elevation >5 times normal had higher late mortality and more unfavorable event-free survival than those patients with normal or lower CK-MB rise after coronary stenting. While intermediate CK-MB elevation (>1 to 5 times normal) is frequent after coronary stenting (26%), this was not associated with an increased risk of late mortality or major adverse clinical events.

Atherosclerotic plaque burden and CK-MB enzyme elevation after coronary interventions : intravascular ultrasound study of 2256 patients

BACKGROUND

Elevation of serum creatine kinase MB fraction (CK-MB) after percutaneous coronary interventions has been associated with early and late mortality; however, the pathogenesis of CK-MB elevation is still unknown. We hypothesized that CK-MB elevation was related to atherosclerotic plaque burden as assessed by preintervention intravascular ultrasound (IVUS).

METHODS AND RESULTS

We studied 2256 consecutive patients who underwent intervention of 2780 native coronary lesions and had complete high-quality preintervention IVUS imaging in the era before routine use of platelet glycoprotein IIb/IIIa inhibitors. Patients were divided into 3 groups: CK-MB within normal range (1675 patients; 2061 lesions); CK-MB elevation 1 to 5 times upper limit of normal (292 patients; 355 lesions); and CK-MB elevation > or = 5 times upper limit of normal (289 patients; 364 lesions). Qualitative angiographic lesion morphology and quantitative analysis were similar among the 3 groups. On preintervention IVUS, progressively more reference segment and lesion site plaque burden and lesion site calcium occurred in the groups with CK-MB elevation. Positive remodeling was more common in lesions with CK-MB elevation. As levels of CK-MB increased, cross-sectional narrowing (percentage plaque burden) increased, both at the reference site (mean cross-sectional narrowing values were 45.1%, <49.3%, and <52.2% for normal CK-MB, 1 to 5 times upper limit of normal, and > or =5 times upper limit of normal groups, respectively; P=0.03) and at the lesion site (81.9%, <85.4%, and <87.1%, respectively; P=0.04). Multivariate analysis indicated that de novo lesions, atheroablative technique, plaque burden at the lesion and reference segments, and final minimal lumen diameter were independent predictors of CK-MB elevation.

CONCLUSIONS

CK-MB elevation correlates with a greater atherosclerotic plaque burden. CK-MB elevation after intervention may be a marker of diffuse atherosclerotic disease or a consequence of catheter-based intervention in more diseased arteries or both.

A double-blind, randomized study of the effect of immediate intravenous nitroglycerin on the incidence of postprocedural chest pain and minor myocardial necrosis after elective coronary stenting

BACKGROUND

Anginal chest pain without creatine kinase (CK) elevation is frequently observed in the first hours after coronary stenting. Possible causes of ischemic episodes are microembolism, side branch occlusion, coronary vasospasm, and disturbances of microvascular circulation. In a prospective, double-blind, randomized trial, we tested the effect of intravenous nitroglycerin on the incidence of angina and minor myocardial necrosis (MMN), as detected by cardiac troponin I increase, after elective coronary stenting.

METHODS AND RESULTS

One hundred patients were randomly assigned to intravenous nitroglycerin (group A: n = 50, goal dose 100 microgram/min) or placebo (group B: n = 50, NaCl 0.9%) during 12 hours after stenting. Patients with acute myocardial infarction, known intolerance to nitrates, and hemodynamic instability during angioplasty were excluded. The 2 groups were comparable in respect to baseline and interventional variables, except for age (group A: 60 +/- 9 years, group B: 56 +/- 10 years; P =.04). The incidence of chest pain was not influenced by nitroglycerin (group A: 18%, group B: 22%; P = not significant). However, the occurrence of MMN was significantly reduced by nitroglycerin (group A: 5%, group B: 19%, P =.036). A rise in CK with significant CK-MB fraction was observed in only 2 patients in group B (both less than twice upper limit). Only 4 of the 10 patients with MMN also had chest pain.

CONCLUSIONS

Routine use of intravenous nitroglycerin after coronary stenting significantly reduced the occurrence of minor myocardial necrosis. However, the incidence of postprocedural chest pain remained unchanged.