Acute myocardial infarction in thrombotic microangiopathies--clinical characteristics, risk factors and outcome.

BACKGROUND: Acute myocardial infarction (AMI) has been reported and is associated with poor outcome in the course of thrombotic microangiopathies (TMA). However, data are very limited in regard to the clinical characteristics, risk factors and outcome of AMI during TMA. Furthermore, current AMI definitions based on troponins are more sensitive and specific to detect myocardial injury. METHODS: We retrospectively analysed 74 consecutive patients with 78 TMA episodes. TMA was defined as platelets below 150 x 10(9)/l, haemolytic anaemia, elevated lactate dehydrogenase (LDH) and increased red cell fragmentation, and AMI as serum troponin I above 1 ng/ml with symptoms of myocardial ischaemia and/or appropriate electrocardiography (ECG) alterations. RESULTS: AMI occurred in 14 TMA episodes (18%) (9 non- and 5 ST-segment elevation AMI). AMI occurred 5+/-3 days after TMA diagnosis, predominately in clinically suspected thrombotic thrombocytopenic purpura (TTP) as TMA subtype. Independent risk factors for subsequent AMI were TTP (RR 2.2; 95% CI 1.1-5.6), and serum LDH above 1,000 U/l (RR 2.7; 95% CI 1.3-7.2) as well as serum troponin I above 0.20 ng/ml at TMA presentation (RR 13.5; 95% CI 2.6-86.8). LDH above 1,000 U/l together with troponin I above 0.20 ng/ml had a sensitivity of 86% (95% CI 60-96%) and a specificity of 95% (95% CI 86-98%) to predict AMI in the later course of TMA. AMI contributed substantially to morbidity causing left ventricular dysfunction in three of eight survivors and potentially accounted for the death in five of six non-survivors. CONCLUSIONS: AMI is an early, frequent and severe complication during TMA. AMI occurs especially in TTP, and serum LDH above 1,000 U/l in combination with serum troponin I above 0.20 ng/ml at TMA presentation are excellent predictors of subsequent AMI.     

Intermittent cardiac troponin-I screening is an effective means of surveillance for a perioperative myocardial infarction

OBJECTIVE: Several studies suggest that cardiac troponin-I (cTn-I) is a more sensitive indicator of cardiac injury compared with other biochemical markers of injury, but the strategy with the highest diagnostic yield (true positive and true negative) for perioperative surveillance is unknown. The authors undertook a prospective evaluation of the perioperative incidence of myocardial infarction (MI) and evaluated surveillance strategies for the diagnosis of MI. DESIGN: Prospective, cohort study. SETTING: Two university hospitals. PARTICIPANTS: Four hundred sixty-seven high-risk patients requiring noncardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The diagnosis of myocardial injury was determined by cardiac protein markers combined with either postoperative changes on 12-lead electrocardiography or 1 of 3 clinical symptoms consistent with MI (chest pain, dyspnea, requirement for hemodynamic support). A receiver operating characteristic curve evaluating troponin in the diagnosis of MI revealed a value of 2.6 ng/mL as having the highest sensitivity and specificity. The sensitivity and specificity of cTn-I value > or =2.6 ng/mL, troponin > or =1.5 ng/mL, total creatine kinase (CK) > or =170 IU/L with MB > or =5%, and CK-MB > or =8 ng/mL were compared. Surveillance strategies were determined on a subset of patients (n = 257). The incidence of MI was 9.0% by cTn-I > or =2.6 ng/mL criteria, 19% by cTn-I > or =1.5 ng/mL, 13% by CK-MB mass, and 2.8% by CK-MB%. The specificity of cTn-I > or =2.6 ng/mL as an indicator of MI was 98%, and its positive predictive value (PPV) was 85%. Cardiac troponin-I > or =2.6 ng/mL had equal specificity but greater PPV than the cTn-I > or =1.5 ng/mL (specificity 98% and PPV 79%). If surveillance of cTn-I > or =2.6 ng/mL was used to detect MI, then the strategy with the highest diagnostic yield was surveillance on postoperative days 1, 2, and 3. CONCLUSIONS: Perioperative cardiac injury continues to occur frequently after noncardiac surgery, as detected by cTn-I. Serial monitoring of cardiac troponin-I on postoperative days 1, 2, and 3 provides the strategy with the highest diagnostic yield for surveillance of MI.     

心脏型脂肪酸结合蛋白在急性心肌梗死早期诊断中的价值

目的探讨心脏型脂肪酸结合蛋白（H-FABP）在急性心肌梗死（AMI）早期诊断中的应用价值。方法检测60例疑似AMI患者H—FABP、心肌肌钙蛋白（cTn）T、肌酸激酶同工酶．MB（CK-MB）水平,按发病时间分为〈6h、6～12h两个时段,计算各项指标诊断AMI的灵敏度,同时测定15例非AMI疑似患者及45例健康体检者的H-FABP、cTnT、CK-MB水平,计算各项指标诊断AMI的特异度。结果H-FABP在发病〈6h诊断AMI的灵敏度为94％,明显优于cTnT的50％、CK-MB的56％,差异均有统计学意义（P〈0．05）;在发病6～12h,H—FABP诊断AMI的灵敏度为100％、cTnT为92％、CK-MB为92％,差异无统计学意义。三项指标诊断AMI的特异度比较差异无统计学意义。结论H—FABP对AMI早期诊断有较高的灵敏度和特异度,适用于胸痛患者的筛查及早期诊断AMI。     

Determination of troponin I release after CABG surgery

BACKGROUND: Troponin I is used to diagnose myocardial infarction (MI). Its use and pattern of elevation is not well defined in coronary artery bypass graft (CABG) surgery. This study assessed the timing of troponin I elevation in patients undergoing urgent CABG. METHOD: Patients undergoing urgent isolated-CABG with cardiopulmonary bypass were studied prospectively. Blood samples were taken to measure CK, CK-MB, and troponin I: preoperatively, 7 hours postoperatively, 14 to 18 hours postoperatively, 30 to 48 hours postoperatively, and on postoperative day 4. Electrocardiograms and in-hospital course were recorded. Perioperative MI (PMI) was defined by either (i) ECG criteria of new Q-waves in the presence of CK-MB elevation >50 microg/L or (ii) CK-MB > 100 microg/L. RESULTS: Of the 50 patients studied, 6 met the criteria for PMI (12%); 2 by criteria (i) and 4 by criteria (ii). In patients not meeting the criteria for MI the troponin I level peaked at 7 hour post-op with a mean of 20.97 microg/L (95% CI, 17.11 to 24.83). At this time, patients who met the criteria for MI had a mean troponin I level of 46.85 microg/L (95% CI, 36.40 to 57.30). Of variables investigated for the 44 patients who did not meet MI criteria, only preoperative troponin I level impacted peak postoperative troponin I. CONCLUSIONS: CABG elevates troponin I far beyond current diagnostic benchmarks without the clinical occurrence of a MI and appears to peak during the second postoperative day. An elevated preoperative troponin I may predict an elevated peak postoperative troponin I in patients who do not have a PMI.     

III: Cardiac troponin T in the diagnosis of perioperative myocardial reinfarction

Diagnosis of a perioperative myocardial infarction (PMI) on the basis of measurement of the creatine kinase MB fraction (CKMB) alone is not always easy. Surgical traumatisation of muscle fibres can lead to false-positive elevations. Newly introduced laboratory tests for cardiac troponins seem to facilitate the diagnosis of PMI. We measured serum values of cardiac troponin T in 139 patients described in detail in part I and compared them with common diagnostic tools for myocardial infarction. Methods. In all, 139 patients were enrolled (part I). Clotted serum samples were taken preoperatively and daily until day 3, centrifuged, and stored at −20° C until analysis. Our Department of Clinical Biochemistry and Haematology used a commercially available sandwich immunoassay (Troponin T ELISA, Boehringer, Mannheim, Germany). The measurements of CK and CKMB were performed with an automated analyser (CK, CK-MB, Boehringer, Mannheim, Germany). Serum values of troponin T were defined according to company recommendations: detection level: 0.04 ng/ml, threshold value for myocardial ischaemia: ≥0.2 ng/ml, value for diagnosis of non-Q-wave infarction: ≥1.0 ng/ml, and value for diagnosis of Q-wave infarction: ≥3.0 ng/ml. We therefore assumed a value of ≥1.0 ng/ml troponin T as being positive for MI, comparable with a CKMB value ≥6% of total CK (part I). Statistical analysis was the same as described in part I. Results. Six of the 139 patients had a perioperative infarction, 3 of them had CKMB levels ≥6%, 3 had an elevation of troponin T ≥1.0 ng/ml. The sensitivity was 50% for both troponin T and CKMB. Values for specificity were 98% for troponin T and 95% for CKMB. Two of 8 patients with troponin T levels ≥0.2 ng/ml preoperatively had a reinfarction (Table 5). Three of 8 patients with preoperative elevations of cardiac troponin T ≥0.2 ng/ml versus 4 of 131 others had left ventricular failure postoperatively (P<0,05). On day 3 significantly more patients with pathological levels of troponin T had left ventricular failure (5 of 12 vs. 0 of 127, P<0.05). Patients with pathological depression of the ST segment on Holter ECG more often had elevations of troponin T values on day 3 than patients without (3 of 25 vs.4 of 75, P=0.048). There was an unexplained coincidence of elevated preoperative serum creatinine levels >120 μmol/l and troponin T values (Table 6). Conclusion. Troponin T is a highly specific marker for perioperative myocardial cell necrosis. Patients with raised levels preoperatively seem to be at higher risk for postoperative reinfarction and left ventricular failure. The prognostic value of such an elevation is not clearly defined, especially in patients with chronic renal failure.      

Troponin levels in patients with myocardial infarction after coronary artery bypass grafting

BACKGROUND: The objective of this study was to evaluate serum cardiac troponin T and I levels in patients in whom electrocardiogram, myocardial scan, and serum CK-MB levels of the MB isoenzyme of creatine kinase indicated perioperative myocardial infarction (MI) after coronary artery bypass grafting (CABG). METHODS: We studied 590 patients who underwent CABG at the Montreal Heart Institute between 1992 and 1996. Postoperative cardiac troponin T levels (493 patients), troponin I levels (97 patients), and activity of the MB isoenzyme of creatine kinase, electrocardiograms, clinical data, and clinical events were recorded prospectively. The diagnosis of perioperative PMI was defined by a new Q wave on the electrocardiogram, by serum levels of the MB isoenzyme of creatine kinase higher than 100 IU/L within 48 hours after operation, or both. RESULTS: After CABG, 22 patients in whom troponin T levels (22/493, 4.5%) and 6 patients in whom troponin I levels (6/97, 6.2%) were measured had sustained a perioperative MI according to current diagnostic criteria. In these patients, troponin T levels higher than 3.4 microg/L 48 hours after CABG best detected the presence of perioperative MI, with an area under the receiver operating characteristic curve of 0.95, a sensitivity of 90%, a specificity of 94%, a positive predictive value of 41%, a negative predictive value of 99%, and a likelihood ratio of 15. Serum troponin I levels higher than 3.9 microg/L 24 hours after CABG confirmed the perioperative MI with an area under the receiver operating curve of 0.86, a sensitivity of 80%, a specificity of 85%, a positive predictive value of 24%, a negative predictive value of 99%, and a likelihood ratio of 5. CONCLUSIONS: Serum troponin T levels higher than 3.4 microg/L 48 hours after CABG correlated best with the diagnosis of perioperative MI. Serum troponin T levels greater than 3.9 microg/L 24 hours after CABG also correlated with the diagnosis of perioperative MI, although a larger experience is needed to confirm the validity of the chosen cutoff value.     

Strict thermoregulation attenuates myocardial injury during coronary artery bypass graft surgery as reflected by reduced levels of cardiac-specific troponin I

We assessed the cardioprotective effects of perioperative maintenance of normothermia by determining the perioperative profile of troponin I, a highly cardiac-specific protein important in risk stratification of patients with acute ischemic events. Candidates for their primary coronary artery bypass grafting (CABG) were randomized into a new thermoregulation system group, Allon( thermoregulation (AT; n = 30), and a routine thermal care (RTC; n = 30) group. Anesthetic and operative techniques were similar in both groups. Intraoperative warming was applied before and after cardiopulmonary bypass (CPB) and up to 4 h after surgery. Perioperative temperature and hemodynamic data were recorded. Blood samples for creatine kinase (CK) and its isoform, MB (CK-MB), and for cardiac-specific troponin I (cTnI) were obtained at predetermined intervals throughout the entire operation. Core and skin temperatures were higher in the AT group at all time points. The systemic vascular resistance was lower and the cardiac index higher in the AT group at all intra- and postoperative time points. Increases in CK, CK-MB, and cTnI levels indicated intraoperative ischemic insult in all patients. The respective CK levels for the AT and RTC groups were 53.3 +/- 22.7 IU/L and 47.9 +/- 17.86 IU/L at the time of anesthesia and 64.7 +/- 45.6 IU/L and 47.8 +/- 19.4 IU/L 30 min after the onset of surgery, demonstrating thereafter a steep increase before the discontinuation of CPB. CK-MB mass concentrations in both groups behaved almost identically. Pre-CPB cTnI levels at anesthesia induction were 0.3 +/- 0 ng/mL in both groups, followed by a distinctive profile observed after separation from CPB: 28.1 +/- 11.4 ng/mL, 26.05 +/- 9.20 ng/mL, and 22.3 +/- 8.9 ng/mL at discontinuation from CPB, chest closure, and 2 h after surgery, respectively, in the RTC group, versus 0.6 +/- 4.6 ng/mL, 6.6 +/- 5.5 ng/mL, and 7.9 +/- 4.76 ng/mL at these three time points, respectively, in the AT group (P < 0.01 between groups at the specified time points). Contrary to conventional thinking about the benefits of hypothermia, maintenance of normothermia throughout the non-CPB phases during CABG was demonstrated to be important in attenuating myocardial ischemic injury. Insofar as troponin I was more sensitive than other tested markers, it may provide important data on possible protection from myocardial insult and on other cardioprotective measures.     

Troponin T — a reliable marker of perioperative myocardial infarction?

Following cardiac surgery, electrocardiography and creatine kinase isoenzyme MB (CK-MB) activities are of limited value in diagnosing a non-transmural infarction. With the recent availability of an assay to detect serial levels of the specific cardiocyte contractile protein troponin T the possibility has been increased of closing a diagnostic gap among cardiosurgical patients. Ninety patients with severe diffuse three-vessel disease undergoing myocardial revascularization were grouped by their postoperative electrocardiographic (ECG) findings (group I — unchanged ECG; group II — new Q-waves representing perioperative myocardial infarction (PMI)). Serial levels of troponin T and the activity of CK-MB were measured 6, 12, 24 and 48 h after aortic unclamping. The course of CK-MB activity was compared to a profile and values derived from patients with unchanged (n = 1312) or new Q-wave ECGS (n = 89). In 72 patients (80.0%) with unchanged postoperative ECG (group I) serial troponin T levels remained constantly low and reached a median peak value of 0.37 μg/l (quartile 0.13–0.50 μg/l) after 24 h. Serial CK-MB activities demonstrated the typical non-ischemic course with a monoexponential decline from an initial median peak value of 15.5 U/l (quartile 12.0–21.0 U/l) to 7.0 U/l (quartile 6.0–9.0 U/l). In seven patients (7.8%) with new Q-waves and a pathologic CK-MB profile (group II) troponin T reached median levels of 10.47 μg/l (quartile 6.34–12.50 μg/l) (P < 0.001 I vs II). Four of five patients with a new right bundle branch block demonstrated low troponin T levels below 1 μg/l and a normal CK-MB profile. Among six patients with unchanged QRS-configuration and elevated troponin T levels between 0.84 and 4.99 μg/l CK-MB activity showed a characteristic PMI pattern in two patients. Troponin T is characterized by a very narrow margin of normal values represented by a maximum third quartile of 0.50 μg/l. A singular value of troponin after 6 h or 24 h may be sufficient evidence to confirm the diagnosis of a PMI.     

Peri-operative myocardial injury in patients undergoing surgery for critical limb ischaemia.

INTRODUCTION: Although up to a half of patients undergoing abdominal aortic aneurysm (AAA) repair suffer myocardial injury, as indicated by a rise in cardiac troponin I (cTnI), this is infrequently accompanied by a rise in creatine kinase (CK)-MB fraction or electrocardiogram (ECG) changes. This study compares for the first time peri-operative cTnI, CK-MB and ECG changes in patients undergoing surgery for critical lower limb ischaemia (CLI). METHODS: Twenty-nine patients (20 men, median age 75 [range, 57-95] years) were studied prospectively. cTnI, CK/CK-MB ratio and ECG were performed pre-operatively and on post-operative days 1, 2 and 3. RESULTS: Eleven (38%) patients had an elevated cTnI >0.5 ng/ml. Five (17%) patients had an elevated CK-MB fraction >4% and all of these patients had an elevated cTnI. Eleven (38%) patients had ischaemic changes on ECG including seven of 11 (64%) patients with elevated cTnI and all five patients with elevated CK-MB fraction. There was no relationship between pre-operative cardiac status, antiplatelet use or type of anaesthesia and post-operative cTnI rise. Patients with a cTnI rise were younger (p=0.01), and were more likely to have presented with gangrene (p=0.04) and have a longer operation time (p=0.01) than patients who did not demonstrate a cTnI rise. Four patients developed clinically apparent cardiac complications: cardio-pulmonary arrest (n=1), cardiogenic shock (n=1), acute CCF (n=1) and rapid atrial fibrillation (n=1). Survival at 6 months was 26 of 29 (90%) patients. CONCLUSION: These data demonstrate that over a third of patients operated for CLI sustain peri-operative myocardial injury, many of which are not clinically apparent. Pre-operative medical optimisation may improve prognosis in this group of patients.     

Predictors of electrocardiographic change, cardiac troponin elevation, and survival after major vascular surgery: a community hospital experience

Cardiovascular disease is the leading cause of perioperative morbidity and mortality after vascular surgery. The purpose of this study was to identify risk factors for myocardial ischemia after vascular surgery and to investigate a potential association of ischemia with mortality in a community hospital setting. A retrospective review was conducted after 190 major vascular procedures. Electrocardiogram (ECG) results and troponin I levels were obtained serially during the first 24 postoperative hours. Outcomes analyzed were ischemic ECG changes, troponin I level more than 2 ng/mL, 6-month mortality, and overall survival. The authors investigated any association of these outcomes with each other and the type of operation, history of coronary artery disease, diabetes, recent coronary intervention, age older than 70 years, or postoperative symptoms. Twenty-seven (14%) patients experienced ischemic ECG changes. Twenty-one (11%) patients experienced troponin I elevation. Univariate analysis revealed a history of coronary artery disease, diabetes, concerning symptoms, and troponin elevation to be predictive of ECG change (P < 0.05). ECG change and symptoms were predictive of troponin elevation (P < 0.01). Cox multivariate analysis revealed only infrainguinal bypass to predict 6-month mortality (odds ratio = 2.92, P = 0.02). Diabetes was the sole predictor of overall mortality (odds ratio = 1.94, P = 0.001). Nonsustained ischemic postoperative ECG changes during the first 24 postoperative hours do not independently influence 6-month or overall mortality after major vascular surgery. Postoperative troponin elevation likely conveys a mortality risk in the subsequent 6 months. In the community hospital setting, midterm survival rates after vascular surgery equivalent to those in higher volume centers can be achieved. Patients undergoing infrainguinal bypass and diabetics continue to be the most moribund vasculopaths.     

Troponin I as a Diagnostic Marker of a Perioperative Myocardial Infarction in the Orthopedic Population

Study Objective: To assess the utility of troponin I, the only molecular marker of myocardial injury not expressed in regenerating muscle, in diagnosing perioperative myocardial infarction (MI) in the setting of orthopedic surgery where false elevations in creatine kinase MB isoenzymes (CKMB) are known to occur.

Design: Prospective study.

Setting: University-affiliated hospital.

Patients: 85 patients with risk factors for coronary artery disease (CAD) who were scheduled for orthopedic surgery, including total knee arthroplasty, 34; total hip arthroplasty, 36; posterior spine fusion, 7; and other orthopedic operations, 8.

Interventions: Patients were observed in the postanesthesia care unit for at least 24 hours where they had an electrocardiogram (ECG) performed, and blood drawn to rule out MI.

Measurements: Blood samples for measurement of creatine kinase MB isoenzymes (CKMB) and troponin I were drawn at 8-hour intervals for up to 24 hours.

Main results: Five (5/85) patients had elevated levels of both CKMB and troponin I postoperatively. New ECG abnormalities were present in all but one patient who had an old anterolateral MI. Troponin I peaked within 16 hours except in one patient where it continued to increase. That female patient developed cardiogenic pulmonary edema. All the others did well clinically. Six patients (6/85) had a positive CKMB index, and a negative troponin I level. None had ECG changes, except for one in whom subsequent cardiac catheterization showed insignificant CAD. They all did well clinically. All patients with an elevated troponin I level had a positive CKMB index.

Conclusions: Troponin I is as sensitive a marker of MI as CKMB in the orthopedic population, but it has a higher specificity in the perioperative setting. Troponin I can be helpful in properly identifying the source of CKMB elevation postoperatively when this elevation is questionable.     

Clinical significance of elevated troponin I levels in patients with nontraumatic subarachnoid hemorrhage

OBJECT: Aneurysmal subarachnoid hemorrhage (SAH) is associated with electrocardiographic abnormalities, regional or focal wall-motion abnormalities on echocardiograms, and/or increased creatine kinase MB isoenzyme (CK-MB) or cardiac troponin I (cTnI). The goal of this prospective study was to compare the sensitivity and specificity of cTnI with those of CK-MB in the prediction of left ventricular dysfunction on echocardiograms in patients with nontraumatic SAH. In addition, those patients with abnormal findings on their echocardiograms and elevated cTnI levels were further evaluated for the presence of coronary artery disease (CAD) by a cardiologist and to determine whether any left ventricular dysfunction that had been detected was reversible. METHODS: The authors obtained electrocardiograms and echocardiograms, and measured serial levels of cardiac enzymes (CK-MB and cTnI) in 43 patients with nontraumatic SAH. Patients with known CAD were excluded. Those patients found to have elevated enzyme levels and abnormal findings on their echocardiograms underwent additional evaluation for CAD. The sensitivity and specificity of both cTnI and CK-MB for detecting left ventricular function were determined. Twenty-eight percent of patients with SAH in the study had elevated cTnI levels within the first 24 hours after hemorrhage. Seven of the 12 patients had evidence of left ventricular dysfunction on echocardiograms. In all these patients a return to baseline function was found during follow-up examinations. The authors found that cTnI is much more sensitive than CK-MB (100% compared with 29%) in the detection of left ventricular dysfunction in patients with SAH. CONCLUSIONS: An elevated level of cTnI is a good indicator of left ventricular dysfunction in patients with SAH. In this study cardiac dysfunction was reversible and should not necessarily preclude these patients from undergoing operative interventions or becoming heart donors. Clinical management may require more aggressive hemodynamic monitoring until cardiac function returns to normal.     

Role of troponin I, myoglobin, and creatine kinase for the detection of early graft failure following coronary artery bypass grafting.

OBJECTIVE: The detection of early graft failure following coronary artery bypass grafting (CABG) enables immediate reintervention and may significantly limit myocardial damage, thus potentially improving outcome. To date, non-invasive indicators of early graft failure following coronary surgery are still of uncertain diagnostic value. METHODS: In a prospective study, patients following isolated CABG with a postoperative serum cardiac troponin I (cTnI) above 20 ng/ml or significant ECG-changes underwent acute repeat angiography. cTnI, myoglobin (Myo), and creatine kinase (CK) were measured preoperatively and at 1, 6, 12, and 24 h after aortic unclamping. Peak values of cTnI, Myo, CK and isoenzyme CK-MB were determined postoperatively. Receiver operating curves (ROC) for cTnI, Myo and CK/CK-MB were constructed at 6, 12, and 24 h after aortic unclamping to differentiate between patients with and without early graft failure. Based on these curves, the area under curve+/-standard deviation (AUC+/-SD), the sensitivity and specificity were calculated. RESULTS: Out of 2078 consecutive patients having undergone isolated CABG from January 2001 to April 2003, 55 fulfilled the inclusion criteria and underwent acute repeat angiography. Early graft failure was found in 35 patients (group 1), whereas 20 patients did not show graft failure (group 2). CTnI and Myo, but not CK and CK-MB levels were significantly increased in group 1 compared to group 2 at 12 and 24 h after aortic unclamping. ROC analysis of cTnI, Myo and CK/CK-MB indicated cTnI as the best discriminator between the groups with 21.5 ng/ml at 12 h (AUC, 0.82+/-0.06; sensitivity, 82%; specificity, 66%) and 33.4 ng/ml at 24 h (AUC, 0.95+/-0.03; sensitivity, 98%; specificity, 82%) and Myo with 887 microg/ml at 12 h (AUC, 0.72+/-0.07; sensitivity, 73%; specificity, 57%) after aortic unclamping. In contrast, CK/CK-MB as well as the appearance of ECG-changes could not separate between the groups. CONCLUSIONS: cTnI, but not Myo and CK served as a reliable marker for the identification of patients with early graft failure following CABG.     

Do we still need CK-MB in coronary artery bypass grafting surgery?

AIM: The aim of this study was to evaluate the role of cardiac Troponin I (cTnI) and CK-MB for early prediction of outcome of patients undergoing coronary artery bypass grafting (CABG) surgery. METHODS: In 134 consecutive patients undergoing CABG-surgery blood samples were analyzed for cTnI concentration and CK-MB activity. ECG, hemodynamic parameters and the need for inotropic support, were continuously registered. Patients were divided into group A (uneventful course), group B (ischemia by ECG, hemodynamic stability) and group C (ischemia by ECG and IABP). RESULTS: After removal of X-clamp an increase cTnI and CK-MB was observed in all patients. Five hrs after stop of CPB group A (8.3+/-4.2 microg/L) had lower cTnI values compared to group B (14.8+/-5.3 microg/L) (p=0.035) and C (54+/-22.8 microg/L) (p=0.023). The cut off value was 14.8 microg/L. Sensitivity and specificity (99%/97%) was higher for cTnI than for CK-MB (90%/30%). The positive predictive value of outcome was better for cTnI (86%) than for CK-MB (33%). CONCLUSION: CTnI is a specific and sensitive marker for evaluation of perioperative myocardial ischemia (PMI). Additional determination of CK-MB activity does not provide further clinical information. CTnI should be the marker of first choice in CABG surgery.     

Cardiac troponin-I accurately predicts myocardial injury in renal failure

Background: Non-specific elevations of creatine kinase isoenzymes (CK-MB) and cardiac troponin-T may be seen in renal failure, confusing the diagnosis of myocardial infarction. Cardiac troponin-I (cTn-I) has been shown to be specific for myocardial damage in several disease states, but has not been prospectively evaluated in the setting of renal failure. Methods: This prospective case series evaluated 56 patients with acute or chronic renal failure or end-stage renal disease to assess the sensitivity and specificity of c-Tn-I for detecting myocardial injury in this patient population. During a 6-month period, patients admitted with suspected myocardial injury by history, physical examination, and electrocardiography were evaluated. Cardiac troponin-I (cTn-I) measurements were assessed between 8 and 48 h after admission. Appropriate medical care and further cardiac testing (echocardiography, stress testing, or arteriography) was performed at the discretion of the primary physician. Results: Myocardial injury was diagnosed in 18/56 (32%) patients by positive cTn-I levels, while only 7/56 (13%) patients had evidence of myocardial damage by CK-MB. Twenty-one of 56 (38%) patients had indeterminate CK-MB levels and 53% of these patients demonstrated myocardial ischaemia on follow-up testing. Sixteen patients had negative cardiac studies; all of these patients had negative cTn-I levels, while seven of these 16 (44%) patients had indeterminate CK-MB measurements. All of the patients with positive cTn-I levels had positive cardiac studies. Positive troponin levels were associated with increased in-hospital mortality. Sensitivity and specificity for CK-MB were 44 and 56% respectively, and 94 and 100% for cTn-I. Conclusion: These data support the use of cTn-I for diagnosing mycocardial injury in patients with renal failure. Elevated cTn-I levels are associated with increased short-term mortality in renal failure patients. The accuracy of cTn-I could potentially limit unnecessary cardiac testing in renal failure patients, while the enhanced sensitivity contributes to risk stratification and aids in diagnosing true myocardial injury in this population susceptible to non-specific elevations in other muscle enzymes.     

Perioperative myocardial cell injury: the role of troponins

Early recognition of minor myocardial cell injury and appropriate treatment may prevent development of myocardial infarction as one of the most severe postoperative cardiac complications. Troponins have been shown to be sensitive biochemical markers for the assessment of myocardial cell injury. We investigated prospectively 67 cardiac risk patients undergoing elective non-cardiac surgery. Troponin T (TNT) concentrations were measured during the perioperative period, and in those patients with increased TNT (cut-off 0.2 ng ml-1), troponin I (TNI) concentrations were measured additionally (cut-off 0.6 ng ml-1). Patients were allocated to one of three groups: group I, all patients with normal TNT concentrations had a good cardiac outcome (80.5%). In those patients with increased TNT concentrations (19.5%) TNI was also positive; group II, patients (8.8%) with only slightly increased TNT concentrations (0.32-0.99 ng ml-1) also had a good outcome, indicating minor myocardial cell injury, whereas patients with cardiac complications (11.9%) had higher TNT concentrations (0.47-9.8 ng ml-1) (P < 0.05) (group III). With a TNT cut-off at 0.2 ng ml-1, the positive predictive value for adverse outcome was 61.5%; the negative predictive value was 100%. With a TNT cut-off at 0.6 ng ml-1, the positive predictive value for adverse outcome increased to 87.5%, but the negative predictive value was still high (98%). Most of the patients showed an increase in TNT content from the day of surgery until the third postoperative day. We conclude that serial troponin measurements during the perioperative period identify pre-, intra- and postoperative myocardial cell injury. The concentration of troponin T may reflect the degree of injury and help categorize the subsequent risk.      

The One Year Incidence of Postoperative Myocardial Infarction in an Orthopedic Population

The diagnosis of a postoperative myocardial infarction (PMI) is important in the orthopedic population because these events can be associated with significant cardiac morbidity. Plasma troponin I (cTnI) analysis has markedly increased our ability to detect myocardial damage. Using cTnI analysis for evidence of a PMI, we prospectively assessed all of our patients for (1) the 1-year incidence of PMI, (2) the clinical consequences of a PMI in relation to the level of the cTnI release, and (3) 6-month follow-up for cardiac complications. During a 12-month period, patients at risk for perioperative myocardial ischemia were assessed for a PMI by serum cTnI levels and daily serial ECGs. Patients with cTnI levels above the reference level (≥0.4 ng/ml) were also assessed for new cardiac regional wall motion abnormalities with an echocardiogram and 6-month postdischarge adverse cardiac events. Of the 758 patients who were assessed for a PMI, 49 patients had detectable cTnI levels (≥0.4 ng/ml); the incidence of a PMI was 0.6% of all surgical cases and 6.5% of those patients were at risk for a cardiac event. A PMI was more common after hip arthroplasty than other orthopedic procedures. Twenty-three patients had a cTnI level >3.0 ng/ml, and 74% these patients (17/23) had anginal symptoms and/or ischemic ECG changes. Nine of these patients (9/23) had new postoperative echocardiographic changes, five (5/23) required emergency transfer to a cardiac care unit, and 10 (10/23) had postoperative cardiac complications. In contrast, 15 patients with levels of cTnI <3.0 ng/ml and without ischemic ECG changes and/or anginal symptoms had no postoperative cardiac complications. Fourteen patients (14/47) had cardiac complications 6 months after discharge, including four cardiac deaths, one fatal stroke, and four patients with unstable anginal episodes that required a change in medical management, and six patients required coronary revascularization. Orthopedic surgical patients with cTnI level <3 ng/ml and without symptoms or ECG changes suggestive of myocardial ischemia (15/49) may have different risks than those with higher-level cTn1. This study was funded by the Department of Anesthesiology, Hospital for Special Surgery, New York, NY.     

Evaluation of Prostate Specific Antigen Density and Transrectal Ultrasonography-Guided Biopsies in 100 Consecutive Patients with a Negative Digital Rectal Examination and Intermediate Serum Prostate Specific Antigen Levels

Background : This study was undertaken to assess the importance of prostate biopsies in patients with a negative digital rectal examination (DRE) and elevated prostate specific antigen (PSA) levels and to investigate the role of PSA density (PSAD) and hypoechoic lesions on transrectal ultrasound (TRUS) in increasing the diagnostic sensitivity and specificity for prostate cancer (PCa). Methods : One hundred patients with varied initial symptoms who had a negative DRE and a PSA level between 4 and 20ng/mL underwent TRUS-guided systematic and, if present, lesion-directed biopsies. Results : PCa was detected in 11 patients (11%). TRUS examinations revealed hypoechoic lesions in 31 patients. Lesion-directed biopsies revealed PCa in 1 3% (4/31) of patients with abnormal TRUS whereas, 7% (5/69) of patients with negative TRUS findings had PCa. Additional systematic biopsies detected PCa in 2 patients where lesion-directed biopsies were negative. None (0/19) of the lesions smaller than 0.2 ml on TRUS had PCa whereas, 33% (4/1 2) of patients with lesions greater than 0.2 ml had PCa. When the subgroup of patients with negative TRUS and PSA levels between 4 and 10ng/mL were considered, 25% (1/4) of cases with PCa would have been missed if 0.15 was used as the cut-off point for PSAD, however, this would save 61% (30/49) of unnecessary biopsies. The positive predictive value of PSA (cut-off level lOng/mL), PSAD (cut-off level 0.15), and hypoechoic lesions on TRUS were found to be 11.5%, 33%, and 13%, respectively. When hypoechoic lesions greater than 0.2 mL were taken as the positive finding, the positive predictive value and specificity rates of TRUS increased to 33% and 91 %, respectively, without any change in the sensitivity. Conclusions : In patients with a negative DRE and intermediate PSA levels, the application of PSAD would have saved 49% of study patients with BPH from a biopsy, but would have missed 27% of PCa cases. By ignoring lesions smaller than 0.2 mL on TRUS, a very high specificity of 91% was achieved with a sensitivity of 36%. Thus, further investigations aimed at defining a better mode of diagnosis of PCa are warranted.     

Prostate-specific antigen (PSA) complexed to alpha1-antichymotrypsin improves prostate cancer detection using total PSA in Japanese patients with total PSA levels of 2.0-4.0 ng/mL

OBJECTIVE: To assess the utility of prostate-specific antigen (PSA) complexed to alpha1-antichymotrypsin (PSA-ACT) in prostate cancer screening in Japanese men with a total PSA level of 2.0-4.0 ng/mL, as improving cancer detection in men with these total PSA levels is a challenge for clinical urologists. PATIENTS AND METHODS: Total PSA and PSA-ACT were prospectively assessed and prostate biopsy recommended for patients who met either of two thresholds, i.e. a total PSA of > or = 2.0 ng/mL or a PSA-ACT of > or= 1.5 ng/mL. The diagnostic ability of total PSA and PSA-ACT, and free-to-total PSA ratio and prostate volume-adjusted density were evaluated by receiver operating characteristic (ROC) analysis. RESULTS: Of 1003 men enrolled, 547 met the biopsy criteria and a biopsy was taken in 315 (57.6%) patients. The area under the ROC curve for PSA-ACT (0.679) was significantly greater than that for total PSA (0.601, P = 0.04) and equivalent to that for the free-to-total ratio (0.686, P = 0.911) in 116 men, including 27 with cancer with total PSA levels of 2.0-4.0 ng/mL. PSA-ACT was more specific than the free-to-total ratio at a sensitivity of 95% (36% vs 18%, P < 0.05). The best variable for discriminating between cancer and benign disease in men with PSA levels of 2.0-4.0 ng/mL was PSA-ACT density (area under the curve 0.852) which provided 66% specificity at a sensitivity of 90%. CONCLUSIONS: PSA-ACT is better than total PSA and equivalent to the free-to-total ratio for detecting prostate cancer in men with PSA levels of 2.0-4.0 ng/mL, and is thus useful for reducing the number of unnecessary biopsies.     

Troponin must be measured before and after PCI to diagnose procedure-related myocardial injury

OBJECTIVE: To evaluate troponin I >99th percentile of normal as a criterion for myocardial injury after percutaneous coronary intervention (PCI). DESIGN: Troponin I and creatine kinase monobasic (CK-MB) were measured in 327 patients before and after percutaneous transluminal coronary angioplasty (PTCA) with stent implantation. RESULTS: Troponin I was elevated before PCI in 100 of a total of 222 patients with acute coronary syndrome (ACS). In 91 of these 100 patients, troponin I was elevated also after PCI but actual increases in troponin I concentrations from before to after PCI were found in only 32 patients. The increase of troponin I correlated with post-procedural CK-MB whereas post-procedural troponin I levels did not correlate. In the 122 patients with ACS but normal/normalized troponin I before PCI and in 105 patients with stable coronary artery disease post-procedural troponin I appeared to be a reliable indicator of myocardial infarction (MI), however more sensitive than CK-MB. CONCLUSION: Troponin I after PCI is sensitive to pre-procedural concentrations. To avoid false positive MI diagnoses we thus suggest that troponin I should be measured before as well as after the procedures and only actual increases should be regarded as indicating procedure-related MI.