Cardiac troponin I to diagnose percutaneous transluminal coronary angioplasty-related myocardial injury

The clinical approach to diagnosing peri-procedural myocardial infarction after percutaneous coronary interventions according to the fourth universal definition of myocardial infarction - from the study group on biomarkers of the European Society of Cardiology (ESC) Association for Acute CardioVascular Care (ACVC)

PURPOSE

This review intends to illustrate basic principles on how to apply the Fourth Universal Definition of Myocardial Infarction (UDMI) for the diagnosis of peri-procedural myocardial infarction (MI) after percutaneous coronary interventions (PCI) in clinical practice.

METHODS AND RESULTS

Review of routine case-based events. Increases in cardiac troponin (cTn) concentrations are common after elective PCI in patients with chronic coronary syndrome (CCS). Peri-procedural PCI-related MI (type 4a MI) in CCS patients should be diagnosed in cases of major peri-procedural acute myocardial injury indicated by an increase in cTn concentrations of >5-times the 99th percentile upper reference limit (URL) together with evidence of new peri-procedural myocardial ischaemia as demonstrated by electrocardiography (ECG), imaging, or flow-limiting peri-procedural complications in coronary angiography. Measurement of cTn baseline concentrations before elective PCI is useful. In patients presenting with acute MI undergoing PCI, peri-procedural increases in cTn concentrations are usually due to their index presentation and not PCI-related, apart from obvious major peri-procedural complications, such as persistent occlusion of a large side branch or no-reflow after stent implantation.

CONCLUSION

The distinction between type 4a MI, PCI-related acute myocardial injury, and chronic myocardial injury can be challenging in individuals undergoing PCI. Careful integration of all available clinical data is essential for correct classification.

Cardiac Troponin I Increase After Successful Percutaneous Coronary Angioplasty: Predictors and Long-Term Prognostic Value

After successful percutaneous coronary interventions (PCI), elevations of cardiac enzymes are not rare, but it is still not clear whether those elevations are associated with adverse late outcome. The purpose of the study was to investigate the relation between cardiac troponin I (cTn-I) increase after successful percutaneous intervention and late outcome. The study consisted of 100 consecutive patients (mean age 56 ±9.8, 84% male) who had successful elective coronary balloon angioplasty with or without stent implantation. Patients with stable angina (n=54) and unstable angina (n=46) were included in the study. Blood samples for measurement of cTn-I were taken before and immediately after the procedure, and every 6 hours for the first 24 hours. Patients with preprocedural cTn-I elevation were excluded from the study. Postprocedural cTn-I elevation was detected in 34 patients (34%, troponin (+) group) and cTn-I levels were normal in 66 patients (66%, troponin (-) group). Logistic regression analysis showed that intervention in patients with unstable angina, stent implantation following balloon dilation, and maximal inflation pressure were the predictors of cTn-I elevation (p=0.035, p=0.038, and p=0.014, respectively). During the prospective follow-up period for 21 ±7.5 months, the incidence of major cardiac events including recurrent angina, acute myocardial infarction, death, and revascularization were not different in patients with and without cTn-I elevation. Overall, major cardiac events occurred in 9 patients (26%) in the troponin (+) group and in 13 patients (20%) in the troponin (-) group. Kaplan-Meier survival analysis showed that cTn-I elevation was not an important correlate of overall cardiac events (log-rank: 1.66, p=0.19). The authors conclude that postprocedural cTn-I elevation is related to unstable angina, stent implantation following predilation, and inflation pressure, and there is no association with minor myocardial injury occurring after successful percutaneous coronary intervention and late adverse cardiac events.

Suppression of Myocardial Injury Markers following Percutaneous Coronary Interventions by Pre-treatment with Carvedilol

BACKGROUND

Retrospective studies and clinical trials have indicated that β-receptor blockers have an influential role in improving survival and reducing risk of recurrent infarction in patients with myocardial infarction. However, there is still controversy regarding the effects of β-receptor blockers on the markers of myocardial infarction following percutaneous coronary interventions (PCI).

OBJECTIVE

The aim of this study was to evaluate the pre-treatment effect of Carvedilol on markers of myocardial injury in patients undergoing elective PCI.

METHOD AND MATERIALS

In this clinical trial patients undergoing elective PCI were categorized randomly in the Carvedilol group including 100 patients who received two doses of 12.5 mg, 6 and 12 hours prior to PCI, and the control group (105 patients). Blood samples were obtained to analyse cardiac biomarker, 12 and 24 hours after PCI.

RESULTS

The clinical features were not significantly different between the two groups. A increase in the level of Troponin I was observed in the control group 24 hours following PCI (P=0.042), whereas this rise in troponin I was slight and insignificant in the Carvedilol group (P>0.05). some difference was observed between the two groups in regard to the level of CPK-MB after PCI (P=0.041).

CONCLUSION

The findings of our study indicate that pre-treatment with Carvedilol confers cardio-protection by limiting the rise of markers of myocardial injury following PCI.

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.

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 troponins and creatine kinase content of striated muscle in common laboratory animals

Animal models are important for the investigation of human heart pathology, novel treatments, and medical or surgical interventions for disease. Serum markers of myocardial damage may also be important tools within this field of research. In order to assess the cardiac specificity of widely utilised serum markers, we measured the cardiac troponins and creatine kinase (CK) isoenzymes in cardiac and skeletal muscle samples taken from dog, monkey, pig and rat. These samples were also analysed by immunoblotting for cardiac troponin I (cTnI) and cardiac troponin T (cTnT). The content of cTnI and cTnT in skeletal muscle was below 0.6% of that found in heart for all animal species studied. This low immunoreactivity in skeletal muscle was confirmed by immunoblot analysis. The content of CK was higher in skeletal muscle than in heart muscle for all species. The CK-MB/total CK ratio was lower in skeletal muscle than in cardiac muscle for all species. The differences in CK-MB content of skeletal muscle and heart muscle were much less pronounced than the tissue differences in the amounts of the cardiac troponins. The cardiac troponins are potentially useful serum markers of myocardial damage, with high specificity for myocardial muscle in these common laboratory animals. Creatine kinase-MB is much less cardiac-specific.

Monitoring plasma cardiac troponin I for the detection of myocardial injury after percutaneous transluminal coronary angioplasty

The objective of this study was to detect myocardial injury defined by an increase of plasma cardiac troponin I (cTnI) following percutaneous transluminal coronary angioplasty (PTCA) and compare plasma cTnI with the risk of cardiac complications at 30 days. Plasma cTnI, creatine kinase (CK) MB, and total CK were determined in 83 patients before (baseline) and 6, 12 and 24 h after PTCA. Thirty-eight patients underwent conventional PTCA, 39 PTCA-stent and six rotational atherectomy. Patients with acute myocardial infarction (AMI) and increased pre-procedural cTnI >0.8 microg/l were categorized into group 1 (n=23). The remaining 60 patients (pre-procedural cTnI=0.8 microg/l) were categorized as follows: group 2 (n=15) AMI; group 3 (n=20) unstable angina (UA); group 4 (n=25) coronary artery disease (CAD). Twelve hours post-procedure, all three cardiac markers were more frequently increased over baseline in group 2 patients (40-60%) compared to patients in group 3 (5-29%, P<0.03) or group 4 (0.5-5%, P<0.01). This was also true for patients undergoing PTCA-stent compared to conventional PTCA or rotational atherectomy (27-40 vs. 4-14%, P<0.02). cTnI was more sensitive (60%) to detect release of myocardial protein after PTCA compared to total CK (47%) or CKMB (43%). A moderate increase of cTnI (0.8-1.5 microg/l) in groups 2, 3 and 4 was associated with higher risk of complications 30 days post-procedure.

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.

Relation of minor cardiac troponin I elevation to late cardiac events after uncomplicated elective successful percutaneous transluminal coronary angioplasty for angina pectoris

There is little information about the relation between mild cardiac troponin I (cTn-I) increase after coronary interventions and late outcome. We therefore focused on the long-term outcome and the clinical, morphologic, and procedural correlates of elevation of cTn-I compared with cardiac troponin T, creatine kinase (CK), CK-MB activity and mass, and myoglobin in 105 patients with successful elective percutaneous transluminal coronary angioplasty (PTCA) for stable or unstable angina. Patients with myocardial infarction and those with unstable angina who had a detectable increase in serum markers before PTCA were excluded. Markers were measured before and after the procedure and for 2 days. Patients were followed up to record recurrent angina, myocardial infarction, cardiac death, repeat PTCA, or elective coronary artery bypass graft surgery. Procedure success was achieved in all cases. Elevation in cTn-I (> or =0.1 microg/L) was observed in 23 of 105 patients (22%) (median peak: 0.25 microg/L); 18% had cardiac troponin T (cTn-T) release (> or = 0.1 microg/L, median peak 0.21); 11.4% CK-MB mass (> or =5 microg/L), and 7.6% myoglobin (> or =90 microg/L) release. Five and 2 patients had elevated CK and CK-MB activity, respectively. Fourteen of 18 patients with cTn-T elevation had a corresponding elevation in cTn-I (kappa 0.68; p = 0.001). Patients positive for cTn-I had more unstable angina (p = 0.042) and heparin before PTCA (p = 0.046), and had longest total time (p = 0.004) and single inflation (p = 0.01). By multivariate logistic regression, predictors of postprocedure cTnI elevation were maximum time of each inflation (odds ratio 9.2; p = 0.0012), type B lesions (odds ratio 6.6; p = 0.013), unstable angina (p = 0.041), and age > or =60 years (p = 0.032). Clinical follow-up was available in 103 patients (98%) (mean 19+/-10 months). Kaplan-Meier survival analysis showed that cTn-I elevation was not an important correlate of cardiac events (p = 0.34, by log-rank analysis). The incidence of recurrent angina, myocardial infarction, cardiac death, and repeat revascularization after 12 months was not different in patients positive or negative for cTn-I. We conclude that cTn-I elevation after successful PTCA is not associated with significantly worse late clinical outcome. Levels of cTn-I allow a much higher diagnostic accuracy in detecting minor myocardial injury after PTCA compared with other markers, but there is no association with periprocedural myocardial cell injury and late outcome when cTn-I and other markers are considered.

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.

Markers of myocardial injury in blood following PTCA: a comparison of CKMB, cardiospecific troponin T and troponin I

In 74 patients undergoing elective PTCA, CKMB, cTnT, cTnI-Access (cTnI-Acc) and cTnI-Abbott (cTnI-Abb) were measured in serum before and days 1 and 4 after the procedure. Two of the patients had pronounced biochemical evidence of AMI. In addition, a minor to moderate increase in CKMB, cTnT, cTnI-Acc and cTnI-Abb were found on day 1 in 13, 22, 18 and 25 patients, respectively. Excluding the two with AMI, cTnT was also increased on day 4 in 16 patients and cTnI-Abb in 15 patients, whereas CKMB and cTnI-Acc levels were essentially normal in all. Thus, an unexpected discrepancy between the two methods for cTnI was revealed on day 4. In these 16 patients, there was no statistically significant relationship between the level of cTnT on day 4 and the levels of CKMB or cTnI-Acc on day 1. This is in contrast to a significant correlation to cTnT and cTnI-Abb on day 1. Based on these results, it is speculated that the marker levels on day 1 are due to reversible as well as irreversible damage, whereas cTnT and cTnI-Abb on day 4 more selectively reflect the degree of myocardial necrosis. cTnT and TnI-Abb on day 4 are therefore proposed as valuable markers for further study of the clinical implications of myocardial damage following PTCA and related interventions.