Myocardial damage during percutaneous transluminal coronary angioplasty as evidenced by troponin T measurements

Impact of multi-vessel therapy to the risk of periprocedural myocardial injury after elective coronary intervention: exploratory study

Backgrounds

Periprocedural myocardial injury (PMI) after elective percutaneous coronary intervention (PCI) significantly influences the prognosis of coronary artery disease (CAD). However, it was unclear whether the occurrence of PMI was associated with a series of controllable factors, such as PCI strategy or severity of CAD.

Methods

A total of 544 consecutive stable CAD patients underwent elective PCI were enrolled. The main outcome is PMI, defined as troponin T after PCI was at least one value above the 99th percentile upper reference limit. Major adverse cardiac events (MACE), including all-cause death, repeat myocardial infarction and target vessel revascularization were record in the period of follow-up. Univariate and multivariate analysis was applied to assess predictors for the occurrence of PMI.

Results

The incidence of PMI was 38.8% in the study. Compared with non-PMI patients (n = 333), PMI patients (n = 211) had more diseased vessels, higher Gensini and Syntax score. Meanwhile, there were higher incidence of MACE in PMI groups (9.5% vs. 3.2%, P < 0.01). We found that PMI patients underwent higher proportion of multi-vessel PCI simultaneously (32.2% vs. 10.5%, P < 0.01) and had more stents implanted (1.8 ± 0.8 vs. 1.4 ± 0.6, P < 0.01). Importantly, after simultaneously adjusted by other factors (such as age, diabetes, total cholesterol, number of diseased vessels, Gensini score and stent length), the risk of PMI was still increased 84% by multi-vessel PCI independently (OR = 1.654, 95% CI = 1.004–2.720, P < 0.05).

Conclusions

The phenomenon of PMI occurred more commonly in stable CAD patients underwent multi-vessel PCI. Multi-vessel international therapy could increase the risk of PMI in elective PCI.

Cardioprotective effects of oral nicorandil use in diabetic patients undergoing elective percutaneous coronary intervention

OBJECTIVE

This study sought to evaluate the cardioprotective role of oral nicorandil (a hybrid between the nitrates and adenosine triphosphate [ATP] sensitive potassium channel activators) in diabetic patients undergoing elective percutaneous coronary intervention (PCI).

BACKGROUND

Myocardial injury commonly occurs during PCI. Several agents that mimic ischemic preconditioning could help minimize this phenomenon.

METHODS

One hundred diabetic patients with stable angina were prospectively enrolled, then randomly assigned to receive oral nicorandil: 20 mg once daily (group A, 50 patients) or placebo (group B, 50 patients) 1 week before and 6 months after PCI. Cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) levels were measured before and 6, 12, and 24 hours post-PCI.

RESULTS

Mean age of the study cohort was 59.8 ± 5.8 years (males = 68%). cTnI level was significantly lower in group A (6 hours: 7.3 ± 0.3 vs. 14.5 ± 0.4 pg/mL; 12 hours: 12.7 ± 0.7 vs. 25.3 ± 0.5 pg/mL; and 24 hours: 7.7 ± 0.5 vs. 15.0 ± 0.4 pg/mL, P < 0.001). After 6 months, the same group showed significantly higher left ventricle ejection fraction (LVEF%), that is, 63.5 ± 7.7% versus 56.5 ± 8.3% (P < 0.05), with a trend toward lower incidence of major adverse cardiac events (MACE).

CONCLUSION

In diabetic patients undergoing elective PCI, nicorandil intake was associated with decreased incidence of PCI-related myocardial injury and improvement of LVEF% after 6 months.

PERIPROCEDURAL MYOCARDIAL DAMAGE

Percutaneous coronary intervention (PCI), as a method of myocardial revascularisation, is widely and effectively used for the treatment of coronary heart disease (CHD), with immediate success rates of >90%. Depending on the diagnostic criteria, 5–30% of these patients could develop the signs of periprocedural myocardial damage (PMD) or periprocedural myocardial infarction (PMI). PMD predictors, mechanisms of PMD development, and its specific clinical features play an important role in the PMI prevention. At present, there is no universal agreement on the definition and diagnostics of periprocedural myocardial necrosis and PMI, or on their impact on the clinical outcomes. According to the results of the recent studies, which are presented in this review, the current criteria of PMI might need to be modified, due to the increasingly high sensitivity of the modern threshold levels of troponin. 

Detection of coronary microembolization by Doppler ultrasound in patients with stable angina pectoris during percutaneous coronary interventions under an adjunctive antithrombotic therapy with abciximab: design and rationale of the High Intensity Transient Signals ReoPro (HITS-RP) study

Background

Embolization of atherosclerotic debris from the rupture of a vulnerable atherosclerotic plaque occurs iatrogenically during percutaneous coronary interventions (PCI) and can induce myocardial necrosis. These microembolizations are detected as high intensity transient signals (HITS) using intracoronary Doppler technology.

Presentation of the hypothesis

In the presented study we will test if abciximab (ReoPro®) infusion reduces high intensity transient signals in patients with stable angina pectoris undergoing PCI in comparison to standard therapy alone.

Testing the hypothesis

The High Intensity Transient Signals ReoPro® (HITS-RP) study will enroll 60 patients. It is a prospective, single center, randomized, double-blinded, controlled trial. The study is designed to compare the efficacy of intravenous abciximab administration for reduction of microembolization during elective PCI. Patients will be randomized in a 1:1 fashion to abciximab or placebo infusion. The primary end point of the HITS-RP-Study is the number of HITS during PCI measured by intracoronary Doppler wire. Secondary endpoints are bleeding complications, elevation of cardiac biomarkers or ECG changes after percutaneous coronary interventions, changes in coronary flow velocity reserve, hs-CRP elevation, any major adverse cardio-vascular event during one month follow-up.

Implications of the hypothesis

The HITS-RP-Study addresses important questions regarding the efficacy of intravenous abciximab administration in reducing microembolization and periprocedural complications in stable angina pectoris patients undergoing PCI.

Trial registration

The trial is registered under http://www.drks-neu.uniklinik-freiburg.de/drks_web/:DRKS00000603.

Systematic analysis of functional and structural changes after coronary microembolization: a cardiac magnetic resonance imaging study

OBJECTIVES

Our study aimed to detect the morphological und functional effects of coronary microembolization (ME) in vivo by cardiac magnetic resonance (CMR) imaging in an established experimental animal model.

BACKGROUND

Post-mortem morphological alterations of coronary ME include perifocal inflammatory edema and focal microinfarcts. Clinically, the detection of ME after successful coronary interventions identifies a population with a worse long-term prognosis.

METHODS

In 18 minipigs, ME was performed by intracoronary infusion of microspheres followed by repetitive in vivo imaging on a 1.5-T MR system from 30 min to 8 h after ME. Additionally, corresponding ex vivo CMR imaging and histomorphology were performed.

RESULTS

Cine CMR imaging demonstrated a time-dependent increase of wall motion abnormalities from 9 of 18 animals after 30 min to all animals after 8 h (0.5 h, 50%; 2 h, 78%; 4 h, 75%; 8 h, 100%). Whereas T2 images were negative 30 min after ME, 4 of 18 animals showed myocardial edema at follow-up (0.5 h, 0%; 2 h, 6%; 4 h, 25%; 8 h, 17%). In vivo late gadolinium enhancement (LGE) was observed in none of the animals after 30 min, but in 33%, 50%, and 83% of animals at 2 h, 4 h, and 8 h, respectively, after ME. Ex vivo CMR imaging showed patchy areas of LGE in all but 1 animal (2 h, 83%; 4 h, 100%; 8 h, 100%). A significant correlation was seen between the maximum troponin I level and LGE in vivo (r = 0.63) and the spatial extent of ex vivo LGE (r = 0.76).

CONCLUSIONS

Our results show that in vivo contrast-enhanced CMR imaging allows us to detect functional and structural myocardial changes after ME with a high sensitivity. Ex vivo, the pattern of LGE of high-resolution, contrast-enhanced CMR imaging is different from the well-known pattern of LGE in compact myocardial damage. Thus, improvements in spatial resolution are thought to be necessary to improve its ability to visualize ME-induced structural alterations even in vivo.

Incidence and determinants of myocardial infarction following percutaneous coronary interventions according to the revised Joint Task Force definition of troponin T elevation

BACKGROUND

Elevations in troponin T (TnT) occur frequently following percutaneous coronary intervention (PCI) and are associated with an adverse prognosis. The Joint ESC/ACC/AHA/WHF Task Force have released a proposal for a universal definition of myocardial infarction (MI), including diagnostic criteria for PCI associated MI. This is based on a TnT cut-point of more than three times the 99th percentile (0.03 ng/ml), which better reflects the precision of the assay. Our study investigated the incidence and predictive factors of a PCI associated MI, using the revised definition.

METHODS

325 patients were studied following PCI with stenting. TnT was collected at both 8 and 18 h following PCI in patients with either stable or unstable angina and normal baseline TnT levels. Comparison was made of both clinical and procedural characteristics of patients with and without a rise in TnT following intervention, using cut points of 0.01 and 0.03 ng/ml.

RESULTS

TnT was elevated > or = 0.03 ng/ml in 27% and > or = 0.01 ng/ml in 39% of patients following PCI. Troponin elevation was significantly more likely in those patients who experienced peri-procedural ischemic symptoms or EKG changes, or in whom abciximab was used. The variables associated with a troponin rise showed a greater difference between TnT positive and negative patients when using 0.03 ng/ml compared to 0.01 ng/ml, suggesting that this may be a better definition of PCI-related MI.

CONCLUSIONS

Approximately one-quarter of low risk patients experience a procedural MI according to the revised definition. Rises in troponin were significantly associated with peri-procedural ischemic symptoms and EKG changes, and abciximab use, consistent with this level of TnT reflecting true myocardial necrosis.

Myocardial protection with enalaprilat in patients unresponsive to ischemic preconditioning during percutaneous coronary intervention

Cardioprotection due to angiotensin enzyme inhibitors is attributed, at least in part, to the inhibition of bradykinin breakdown and the preconditioning effect of the elevated endogenous bradykinin level. We have previously shown that in patients undergoing percutaneous coronary intervention, one 120-second balloon inflation is insufficient to precondition the heart. The objective of the present study was to examine whether the administration of enalaprilat to these patients results in protection. Twenty patients underwent two 120-second coronary artery occlusions separated by a reperfusion interval of 10 min. Ten patients were given 50 µg·min–1 enalaprilat in an intracoronary infusion between the balloon inflations, whereas the others received an infusion of saline. In the latter control patients, there were no significant differences in ST-segment elevation between the consecutive occlusions (peak ST: 1.61 ± 0.17 vs. 1.61 ± 0.16 mV; time to reach 0.5 mV ST elevation: 16 ± 4 vs. 22 ± 7 s; mean ST: 1.03 ± 0.12 vs. 1.02 ± 0.11 mV). In the patients who received enalaprilat before the second balloon inflation, the ST-segment elevation was significantly less pronounced and slower during the second inflation than during the first (peak ST: 1.80 ± 0.18 vs. 1.41 ± 0.19 mV; time to reach 0.5 mV ST elevation: 18 ± 4 vs. 30 ± 4 s; mean ST: 1.04 ± 0.11 vs. 0.85 ± 0.14 mV). We conclude that enalaprilat administered during percutaneous coronary intervention provides protection to patients who do not have a protective response to the initial balloon inflation.

Distal protection in cardiovascular medicine: current status

Iatrogenic and spontaneous downstream microembolization of atheromatous material is increasingly recognized as a source of cardiovascular morbidity and mortality. Devising ways of reducing this distal embolization using a variety of mechanical means--distal protection--is currently under intense and diverse investigation. This review therefore summarizes the present status of distal protection. It examines the problem of distal embolization, describes the available distal protection devices, reviews those areas of cardiovascular medicine where distal protection devices are being investigated, and discusses potential future developments.

Preprocedural C-reactive protein levels predict myocardial necrosis after successful coronary stenting in patients with stable angina

BACKGROUND

Myocardial necrosis as assessed by cardiac troponin elevation occurs frequently after coronary stenting and is associated with adverse clinical outcome. Mechanical factors have been implicated in this complication and the role of systemic inflammation is not known.

METHODS

We prospectively studied 208 patients with chronic stable angina who underwent elective coronary stenting. All patients had normal troponin levels before the procedure. Blood samples for high-sensitivity C-reactive protein (CRP) were obtained before the procedure and analyzed using a high-sensitivity kit. Cardiac troponin T (cTnT) was obtained 24 hours after the procedure.

RESULTS

Postprocedural cTnT elevations were observed in 46 (22%) patients. There were 11 (16%), 14 (20%), and 21 (30%) patients with elevated postprocedural cTnT in the first, second, and third CRP tertile, respectively (P for trend = .045). In a multivariate logistic regression model, adjusting for all the significant univariate predictors and for statin therapy, CRP remained a significant independent predictor of postprocedural cTnT elevation with an odds ratio of 2.6 in patients in the third CRP tertile compared with patients in the first CRP tertile (95% CI 1.1-6.0, P = .02). Patients in the third CRP tertile also had higher cTnT elevations compared with patients in the first and second CRP tertile (P = .03).

CONCLUSIONS

Elevated baseline CRP levels are associated with higher risk of postprocedural troponin elevations in patients with stable angina undergoing uncomplicated coronary stenting. These results underscore the role of systemic inflammation in the pathogenesis of periprocedural myocardial injury.

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.

Effects of metoprolol therapy on cardiac troponin-I levels after elective percutaneous coronary interventions

AIMS

Beta-blockers (BBs) have been shown to improve survival and reduce the risk of re-infarction in patients following myocardial infarction. There are conflicting data about the effects of BB therapy on cardiac biomarkers after percutaneous coronary interventions (PCIs). The aim of the study was to investigate the effects of BB use on cardiac troponin-I (cTnI) levels in patients who had undergone elective PCI.

METHODS AND RESULTS

In this prospective study, 287 patients with coronary artery disease were included. Patients were randomized either to BB or control groups prior to the intervention. Blood samples for cTnI were obtained before and at 6, 24, and 36 h after the procedure. Of the 287 patients included, 143 received metoprolol succinate 100 mg/day, and 144 received no BB and served as the control group. Baseline clinical characteristics of both groups, except for history of coronary artery bypass graft surgery, were similar. We observed no significant difference in the elevation of cTnI levels between the two groups after PCI (BB group, 17 patients, 11.9%; control group, 10 patients, 6.9%; P=0.2).

CONCLUSION

Metoprolol succinate therapy seems to have no cardioprotective effect in limiting troponin-I rise after PCI.

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.

Detection of coronary microembolisation by Doppler ultrasound during percutaneous coronary interventions

OBJECTIVE

To validate an intracoronary Doppler ultrasound device for high intensity transient signals (HITS) detection and to assess the incidence of HITS during percutaneous coronary intervention (PCI).

METHODS AND RESULTS

In an in vitro model, particle count and number of HITS detected by an intracoronary 0.014 inch Doppler wire were closely correlated (r = 0.97, p < 0.001). In the clinical study, 32 patients (mean (SD) age 61 (11) years; 23 men, nine women) with coronary artery disease were treated with balloon dilatation and stent implantation for a single vessel stenosis. In these patients HITS were detected during PCI in 84% (27 of 32). Reproducibility (r = 0.99, p < 0.001) and interobserver agreement (r = 0.84, p < 0.001) of HITS counts were significant. The number of HITS after stent implantation was significantly higher than after balloon dilatation (11 (7) v 2 (4), p < 0.001). Postprocedural coronary flow velocity reserve (CFVR) was < 2.0 in 55% (16 of 29) of all patients after balloon dilatation and < 2.0 in 23% (six of 26) after stent implantation. The number of HITS after stent implantation did not differ significantly between patients with CFVR < 2.0 and patients with CFVR > or = 2.0 (12 (8) v 10 (7), not significant).

CONCLUSIONS

Embolic particles can be detected as HITS by an intracoronary Doppler ultrasound device. Coronary microembolism is often observed during PCI, especially after stent implantation. However, the incidence of HITS alone does not explain a reduced CFVR after PCI.

Troponin elevation after percutaneous coronary intervention directly represents the extent of irreversible myocardial injury: insights from cardiovascular magnetic resonance imaging

BACKGROUND

Although troponin elevation after percutaneous coronary intervention (PCI) is common, uncertainties remain about the mechanisms of its release and its relationship to the volume of myocardial tissue loss. Delayed-enhancement MRI of the heart has been shown to reliably quantify areas of irreversible myocardial injury. To investigate the quantitative relationship between irreversible injury and cardiac troponin release, we studied the incidence and extent of new irreversible injury in patients undergoing PCI and correlated it to postprocedural changes in cardiac troponin I.

METHODS AND RESULTS

Fifty patients undergoing PCI were studied with preprocedural and postprocedural (24 hours) delayed-enhancement MRI for assessment of new irreversible myocardial injury. Cardiac troponin I measurements were obtained before PCI and 24 hours after PCI. Of these 50 patients, 24 underwent a further third MRI scan at a median of 8 months after the procedure. Mean patient age was 64+/-12 years. After the procedure, 14 patients (28%) had evidence of new myocardial hyperenhancement, with a mean mass of 6.0+/-5.8 g, or 5.0+/-4.8% of total left ventricular mass. All of these patients had raised troponin I levels (range 1.0 to 9.4 mug/L). Thirty-four patients (68%) had no elevated troponin I and no evidence of new myocardial necrosis on MRI. There was a strong correlation between the rise in troponin I measurements at 24 hours and mean mass of new myocardial hyperenhancement, both early (r=0.84; P<0.001) and late (r=0.71; P<0.001) after PCI, although there was a trend for a reduction in the size of PCI-induced myocardial injury in the late follow-up scan (P=0.07).

CONCLUSIONS

In the setting of PCI, patients demonstrating postprocedural elevation in troponin I have evidence of new irreversible myocardial injury on delayed-enhancement MRI. The magnitude of this injury correlates directly with the extent of troponin elevation.

Elevated troponin-I after percutaneous coronary interventions: Incidence and risk factors

BACKGROUND

Percutaneous coronary interventions (PCIs) are often complicated by postprocedural myocardial necrosis as manifested by elevated cardiac markers.

PURPOSE

To assess the incidence and risk factors of elevated troponin-I (TnI) after PCI.

METHODS AND RESULTS

We performed a retrospective analysis on 522 PCI cases over a 1-year period at a single center. An elevated postprocedural TnI (>1.0 ng/ml) occurred in 213 patients (40.8%). Overall, glycoprotein (GP) IIb/IIIa inhibitors were used in 52% of cases. Baseline clinical characteristics were similar between the positive and the negative TnI groups. A univariate analysis revealed that patients with elevated TnI post-PCI had significantly more multivessel (28% vs. 15%, P = .001) and multilesion interventions (44% vs. 27%, P<.0001). The lesions were longer, more often angulated and involving bifurcations, and more complex in the TnI-positive group. Stent use and number of stents was higher in the TnI-positive group, and longer inflation times (>30 s) or higher inflation pressures (>14 atm) were used more often in the TnI-positive group. GP IIb/IIIa inhibitor use was higher in the TnI-positive group (61% vs. 45%, P = .0007). After multivariable analysis, independent predictors of elevated TnI after PCI included multilesion intervention, lesion length, lesion angulation, and GP IIb/IIIa inhibitor use.

CONCLUSION

TnI is elevated in approximately 40% of cases after PCI. TnI is more likely to be elevated after intervention on multiple lesions, angulated or long lesions.

C-reactive protein and myocardial infarction during percutaneous coronary intervention

OBJECTIVE

To evaluate the prognostic information of preprocedural C-reactive protein (CRP) levels in serum to predict myocardial infarction during percutaneous coronary interventions (PCI).

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

A total of 400 consecutive patients with normal serum troponin T levels (</=0.03 microg L-1) presenting with stable or unstable angina pectoris.

INTERVENTIONS

PCI.

MAIN OUTCOME MEASURES

C-reactive protein levels in serum measured by a high sensitive method. Myocardial infarction defined as a serum troponin T elevation the day after PCI to a level >0.05 microg L-1.

RESULTS

Eighty-three patients (21%) experienced a myocardial infarction during PCI. The median value of CRP before the procedure was 1.83 (0.12-99.7) mg L-1. No difference was seen in CRP levels before PCI between patients without or with myocardial infarction during PCI. Multivariate analysis identified stent implantation (OR 2.68, 95% CI 1.18-7.28, P = 0.03), procedure time (OR 2.15, 95% CI 1.28-3.67, P < 0.005) and complications during the procedure (OR 3.62, 95% CI 1.72-7.58, P < 0.001) as independent predictors of myocardial infarction during PCI.

CONCLUSION

Increased CRP levels in serum before PCI were not associated with myocardial infarction during the procedure. Furthermore, patients with an expected long procedure and a high probability of stent implantation have an increased risk of developing myocardial infarction during PCI. This finding may be useful to help the operator to decide the antithrombotic regime before, during and after the procedure and the need for observation after the procedure.

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.

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.

Nicorandil-induced preconditioning as evidenced by troponin T measurements after coronary angioplasty in patients with stable angina pectoris

Nicorandil has been reported to have a preconditioning effect which suppresses the ST-segment shift or lactate production during coronary angioplasty in patients with stable angina pectoris. The present study investigated whether the preconditioning effect of nicorandil affects troponin T (TnT) levels after coronary angioplasty. Twenty-four patients with stable angina pectoris were randomized to receive a 1-minute intravenous infusion of nicorandil (100 microg/kg) or normal saline. Five minutes later they underwent three 2-minute balloon inflations 5 minutes apart. The sum of ST-segment elevation in all leads (Sum-ST) was determined at the end of each balloon inflation. Serum levels of TnT were measured 6 and 18 hours after the procedure, and the higher value of the two measurements was compared between the groups. SumST decreased progressively during the three sequential balloon inflations in both groups and was less in the nicorandil group than in the control group. The TnT level after the procedure was significantly lower in the nicorandil group than in the control group (0.05+/-0.05 vs 0.11+/-0.10 ng/mL). In conclusion, pretreatment with intravenous nicorandil suppresses TnT release after coronary angioplasty as well as ST-segment elevation during coronary angioplasty, suggesting pharmacological preconditioning by nicorandil.

Effect of additional temporary glycoprotein IIb/IIIa receptor inhibition on troponin release in elective percutaneous coronary interventions after pretreatment with aspirin and clopidogrel (TOPSTAR trial)

OBJECTIVES

The Troponin in Planned PTCA/Stent Implantation With or Without Administration of the Glycoprotein IIb/IIIa Receptor Antagonist Tirofiban (TOPSTAR) trial investigated: 1) the amount of troponin T (TnT) release after nonacute, elective percutaneous coronary intervention (PCI) in patients pretreated with aspirin and clopidogrel; and 2) the effect of additional glycoprotein (GP) IIb/IIIa receptor inhibiton on postinterventional TnT release.

BACKGROUND

No data are available yet as to whether additional administration of a GP IIb/IIIa receptor antagonist might be beneficial in patients undergoing elective PCI already pretreated with aspirin and clopidogrel.

METHODS

After bolus application of the study medication (tirofiban [T] or placebo [P]), PCI was performed followed by an 18-h continuous infusion of T/P. Primary end point of the study was incidence and amount of TnT release after elective PCI after 24 h.

RESULTS

A total of 12 h after PCI troponin release was detected in 63% of the patients receiving P and in 40% of the patients receiving T (p < 0.05), after 24 h in 69% (P) and 48% (T) (p < 0.05) and after 48 h in 74% (P) versus 58% (T) (p < 0.08) of the patients. No differences were observed regarding major bleeding, intracranial bleeding or nonhemorrhagic strokes. After nine months a reduction of combined death/myocardial infarction/target vessel revascularization could be observed in the tirofiban group ([T] 2.3% vs. [P] 13.04%, p < 0.05).

CONCLUSIONS

Troponin T release occurs after successful intervention in 74% of the patients undergoing elective PCI after 48 h even after pretreatment with aspirin and clopidogrel. The GP IIb/IIIa receptor antagonist tirofiban is able to decrease the incidence of troponin release significantly in this patient population.

Prognostic significance of elevated troponin I after percutaneous coronary intervention

OBJECTIVES

We sought to assess the incidence and clinical significance of elevated cardiac troponin I (cTnI) after percutaneous coronary intervention (PCI).

BACKGROUND

Elevated creatine kinase-MB (CK-MB) is prognostically important after PCI, but the prognostic significance of elevated cTnI after PCI is uncertain.

METHODS

In a prospective substudy of the Sibrafiban Versus Aspirin to Yield Maximum Protection From Ischemic Heart Events Post-acute Coronary Syndromes (SYMPHONY) trials, which randomized patients with acute coronary syndromes (ACS) to receive aspirin or sibrafiban, we measured cTnI (positive, > or =1.5 ng/ml) and CK-MB (positive, > or =7 ng/ml) in 481 patients with PCI. Samples were collected immediately before and at 0, 8 and 16 h after PCI and analyzed by a core laboratory. The primary end point was the Kaplan-Meier estimate of death, myocardial infarction or severe, recurrent ischemia at 90 days.

RESULTS

Overall, 230 patients (48%) had elevated cTnI after PCI. Such patients underwent PCI sooner and were more likely to have coronary stenting. Elevated cTnI was associated with nonsignificantly higher risks of the primary end point (11.5% vs. 8.7%; p = 0.15) and of death (1.8% vs. 0.4%; p = 0.4) and a significantly higher risk of death or infarction (10.6% vs. 4.2%; p = 0.005). This pattern was more pronounced for patients who became positive only after PCI: primary end point, 20.7% vs. 10.1% for patients who remained negative after PCI (p = 0.05); death, 5.2% vs. 0% (p = 0.02); death or infarction, 18.1% vs. 4.1% (p = 0.007).

CONCLUSIONS

Elevated cTnI, often observed after PCI in patients with ACS, is associated with worse 90-day clinical outcomes. This marker, therefore, is a useful prognostic indicator in such patients.

Importance of microembolization and inflammation in atherosclerotic heart disease

Considerable evidence now exists that inflammation is a central component of events that initiate and propagate an acute coronary syndrome. This process evokes the potential for embolization, which occurs more often than previously suspected, and imparts poor cardiovascular prognosis. Recent development of techniques to detect inflammation and embolization represents an important advance. In addition, therapies that diminish occurrence of these phenomena such as aspirin, statins, angiotensin converting enzyme (ACE) inhibitors, and IIb/IIIa receptor antagonists have been shown to improve outlook.

Troponin T in the coronary sinus and percutaneous transluminal coronary angioplasty related myocardial injury

1. Myocardial injury has been shown to be associated with successful percutaneous transluminal coronary angioplasty (PTCA). The present study was designed to determine whether uncomplicated successful PTCA results in myocardial injury by measuring coronary sinus (CS) cardiac troponin T (cTnT). 2. We measured cTnT in the CS and the femoral vein (FV) in 16 patients with stable angina pectoris who underwent uncomplicated PTCA for stenotic lesions of the left anterior descending artery. Blood samples were drawn from both the CS and FV before and immediately after PTCA and every 4 h for the next 12 h. 3. All patients had chest pain and electrocardiographic ST segment elevation or depression during balloon inflation and higher peak elevation of cTnT in the CS than in the FV (0.054 +/- 0.059 vs 0.036 +/- 0.022 ng/mL; P < 0.05). However, all CS cTnT levels were within the normal range over the 12 h period. 4. The fact that CS cTnT measurements showed no evidence of uncomplicated PTCA-related myocardial injury led us to conclude that uncomplicated successful PTCA does not cause myocardial injury.

Frequency and prognostic value of cardiac troponin I elevation after coronary stenting

Mild myocardial injuries after coronary angioplasty are associated with adverse late outcomes. The incidence and prognostic value of this phenomenon when using cardiac troponin I (cTnI) after stent implantation is unknown. We studied cTnI and creatine kinase (CK) release in 109 patients after stenting. Clinical success was achieved in 103 patients (94%). In-hospital major adverse coronary events were: death in 1 patient, Q-wave myocardial infarction in 1 patient, and non-Q-wave myocardial infarction in 2 patients. Twenty-nine patients (27%) had postprocedural cTnI increase, 16 (15%) had CK elevation. No preprocedural variables predicted marker elevation. Marker release was related to the occurrence of in-lab complications (59% vs 29% [p = 0.004 for cTnI] and 69% vs 32% [p = 0.011 for CK]). In 34% no explanation was found for cTnI increase. Success was more frequent in patients without cTnI elevation (100% vs 86%, p <0.001). The negative predictive value of cTnI increase was 100% for in-hospital major adverse coronary events (MACE), whereas its positive predictive value was 14%. cTnI and CK concordant elevation was associated with more intra- and postprocedural adverse events. During a mean follow-up of 8+/-3 months, major adverse coronary events were: death in 2 patients, myocardial infarction in 2 patients, and repeat PTCA in 8 patients. cTnI elevation was not predictive of these late MACE. cTnI elevation is common after stenting, and is related to the occurrence of in-lab complications. Its isolated elevation is not a good predictor of MACE. Patients with concordant cTnI and CK elevation seem to be at higher risk of in-hospital MACE.

Intraoperative cardiac troponin T release and lactate metabolism during coronary artery surgery: comparison of beating heart with conventional coronary artery surgery with cardiopulmonary bypass

OBJECTIVE

To compare cardiac troponin T release and lactate metabolism in coronary sinus and arterial blood during uncomplicated coronary grafting on the beating heart with conventional coronary grafting using cardiopulmonary bypass.

DESIGN

A prospective observational study with simultaneous sampling of coronary sinus and arterial blood: before and 1, 4, 10, and 20 minutes after reperfusion for analysis of cardiac troponin T and lactate. Cardiac troponin T was also analysed in venous samples taken 3, 6, 24, 48, and 72 hours after surgery.

SETTING

Cardiac surgical unit in a tertiary referral centre.

PATIENTS

18 patients undergoing coronary grafting on the beating heart (10 single vessel and eight two-vessel grafting) and eight undergoing two-vessel grafting with cardiopulmonary bypass.

RESULTS

Cardiac troponin T was detected in coronary sinus blood in all patients by 20 minutes after beating heart coronary artery surgery before arterial concentrations were consistently increased. Peak arterial and coronary sinus cardiac troponin T values on the beating heart during single (0.03 (0 to 0. 05) and 0.09 (0.07 to 0.16 microg/l, respectively) and two-vessel grafting (0.1 (0.07 to 0.11) and 0.19 (0.14 to 0.25) microg/l) were lower than the values obtained during cardiopulmonary bypass (0.64 (0.52 to 0.72) and 1.4 (0.9 to 2.0) microg/l) (p < 0.05). The area under the curve of venous cardiac troponin T over 72 hours for two-vessel grafting on the beating heart was less than with cardiopulmonary bypass (13 (10 to 16) v 68 (26 to 102) microg.h/l) (p < 0.001). Lactate extraction began within one minute of snare release during beating heart coronary surgery while lactate was still being produced 20 minutes after cross clamp release following cardiopulmonary bypass.

CONCLUSIONS

Lower intraoperative and serial venous cardiac troponin T concentrations suggest a lesser degree of myocyte injury during beating heart coronary artery surgery than during cardiopulmonary bypass. Oxidative metabolism also recovers more rapidly with beating heart coronary artery surgery than with conventional coronary grafting. Coronary sinus cardiac troponin T concentrations increased earlier and were greater than arterial concentrations during beating heart surgery, suggesting that this may be a more sensitive method of intraoperative assessment of myocardial injury.

Cardiac troponin I and troponin T: recent players in the field of myocardial markers

The troponin (Tn) complex consists of three subunits referred to as TnT, TnI and TnC. Myocardium contains TnT and TnI isoforms which are not present in skeletal muscles and which can be separated from the muscular isoforms by immunological techniques. Using commercially available immunoassays, clinical laboratories are able to determine cardiac TnT and TnI (cTnT and cTnI) quickly and reliably as classical cardiac markers. After acute myocardial infarction, cTnT and cTnI concentrations start to increase in serum in a rather similar way than CK-MB, but return to normal after longer periods of time (approximately one week). Because of their excellent cardiac specificity, Tn subunits appear ideally suited for the differential diagnosis of myocardial and muscular damage, for example in noncardiac surgery patients, in patients with muscular trauma or with chronic muscular diseases, or after intense physical exercise. cTnT and cTnI may also be used for detecting evidence of minor myocardial damage: therefore they have found new clinical applications, in particular risk stratification in patients with unstable angina. In spite of the possible reexpression of cTnT in human skeletal muscles, and of the lack of standardization of cTnI assays, Tn subunits are not far to meet the criteria of ideal markers for acute myocardial injury. Only an insufficient sensitivity in the first hours following the acute coronary syndroms requiries to maintain an early myocardial marker in the cardiac panel for routine laboratory testing.