Troponin T and I are not reliable markers of cardiac transplant rejection

OBJECTIVE

Heart transplant recipients undergo a number of invasive endomyocardial biopsies to screen for rejection. Serum assays of troponin T and/or I may provide a less invasive alternative. The purpose of this study was to evaluate troponin T and I as markers of cardiac transplant rejection.

METHODS

We conducted a prospective analysis comparing troponin T and I levels to biopsy results in heart transplant recipients. Plasma was assayed for troponin T and I preoperatively, on the first 3 postoperative days, and with each subsequent biopsy.

RESULTS

Twenty-nine patients entered the study. A total of 173 biopsies were performed at a mean follow-up of 129+/-9 days (range: 12-564 days). There were two rejection episodes (> or = grade 3), one in each of two patients. There were no significant relationships between troponin T or I and biopsy-proven rejection (> or = grade 3; P=0.59 and 0.54, respectively). There were also no correlations between troponin T or I levels and biopsy grade (P=0.40 and 0.92, respectively). Troponin T and I levels peaked on postoperative day 1 and fell to baseline over long-term follow-up with no peak in serum markers associated with rejection episodes. Donor ischemic time was significantly correlated to troponin T on postoperative days 1-3 (r=0.58, P=0.005; r=0.61, P=0.004; and r=0.61, P=0.003, respectively).

CONCLUSIONS

Troponin T and I are not useful indicators of cardiac rejection, but do correlate with donor heart ischemic injury.

An unusual case of ST elevation in a 39-year-old man

A 39-year-old man presented to a university hospital emergency department with anginal chest pain, ventricular tachycardia and ST elevation in the anterolateral leads (V3 to V6, I and aVL). Due to discrepancies in the history and physical examination, thrombolysis was withheld until a past electrocardiogram could be obtained, which was unchanged. Subsequent investigations revealed no evidence of myocardial necrosis, and the patient was diagnosed with hypertrophic cardiomyopathy. This is the first reported case of hypertrophic cardiomyopathy with ST elevation as the predominant electrocardiographic abnormality. In patients with discrepancies in the clinical presentation, it is essential to obtain past elecrocardiograms to ensure appropriate utility of thrombolysis.

Changing practice patterns in the management of acute myocardial infarction complicated by cardiogenic shock: elderly compared with younger patients

BACKGROUND

Cardiogenic shock continues to be an ominous complication of acute myocardial infarction (AMI). Evidence from retrospective analyses, registries and observational studies suggests that aggressive management using emergent revascularization strategies can bring about significant improvement in survival in this setting. Several studies have identified age as an independent predictor of survival.

OBJECTIVE

To study retrospectively the possible changes in practice patterns in the management of patients with AMI complicated by cardiogenic shock in a tertiary care referral centre, and to determine what effect these changes may have had on survival of the patients, stratified by age.

METHODS

From 1989 to 1995, 115 patients fulfilled the study criteria of cardiogenic shock based on pump failure and of presenting within 48 h of onset of shock. Prespecified data were extracted from medical records. All available coronary angiograms (n = 72) were analyzed by two experienced angiographers and consensus of findings was obtained.

RESULTS

The study revealed a significant increase in the use of cardiac catheterization, interventional procedures and intra-aortic balloon pump (IABP) support in patients in the age groups 65 years or less, 66 to 75 years, and older than 75 years in 1989 to 1990, through 1991 to 1992, to 1993 to 1995. Significantly fewer patients aged older than 75 years received cardiac catheterization, coronary intervention and IABP support throughout the study period and even in the final period analyzed. In-hospital survival improved from 4% in 1989-90 to 33% in 1991-92, and 44% in 1993-95 (P = 0.001). Patients aged 65 years or less improved from 10% in 1989-90 to 59% in 1993-95 (P = 0.032). Only 20% of patients aged older than 75 years survived in the 1993-95 period. By univariate analysis, use of coronary angiography (catheterization 46% versus no catheterization 5%; P < 0.0001), coronary intervention procedures (percutaneous transluminal coronary angioplasty or coronary artery bypass grafting) (intervention 48% versus no intervention 9%; P < 0.0001) and IABP support (IABP 41% versus no IABP 18%; P = 0.0096) were all associated with improved in-hospital survival. Use of thrombolytic therapy showed possible survival benefit only in patients aged older than 75 years (thrombolysis 33% versus no thrombolysis 5%; P = 0.10). Patients who underwent coronary intervention were younger (P = 0.002), had a lower incidence of previous myocardial infarction (P = 0.0002), lower heart rate (P = 0.04), higher peak creatine phosphokinase (P = 0.04) and fewer vessels with at least 70% stenosis (P < 0.0001). On multivariate analysis only lower age, lower heart rate and presence of coronary intervention procedures were found to have an independent effect on survival.

CONCLUSIONS

Use of invasive treatment strategies has increased significantly since 1989-90 in the management of patients with AMI complicated by cardiogenic shock. This increase has been associated with improved in-hospital survival in all age groups except possibly the very elderly. Patients undergoing coronary interventional procedures are significantly different in baseline clinical characteristics from patients not undergoing these procedures. These observations underscore the need for randomized trials to define the optimal treatment strategies in these patients. Efficacy of invasive treatment strategies in elderly patients aged older than 75 years-deserves special attention.

Spectrum of ischemic heart disease and the role of biochemical markers

An exciting era exists as a result of the introduction of novel markers of myocardial damage. The prognostic implications of troponins, even in the setting of "minor myocardial damage," are potentially of immense value to patient care. We need to take the next step and assess the outcomes of interventions in these settings. Use of new markers at triage will probably allow for more efficient and safe disposition of patients in this setting. There are many advantages and disadvantages to the current markers and many unanswered questions. Only through well-designed large clinical trials will we be able to realize the true potential of these markers.

Quantitative relation of electrocardiographic and angiocardiographic measures of risk in patients with coronary atherosclerosis. Simvastatin/Enalapril Coronary Atherosclerosis Trial (SCAT) Investigators

OBJECTIVE

To correlate angiocardiographic and electrocardiographic (ECG) measures of risk in coronary artery disease (CAD) patients.

SETTING

Baseline substudy of the Simvastatin/Enalapril Coronary Atherosclerosis Trial (SCAT), a 2 x 2 factorial, randomized, controlled trial of CAD regression.

PATIENTS

One hundred and twenty-three CAD patients, 113 males and 10 females; average age, 59 years.

METHODS

Bivariate correlations of multiple quantitative measures of epicardial coronary angiographic luminal narrowing (quantitative coronary angiography [QCA]) and body surface ECG maps of the sum of the decrease in the potential time integral of the ST segment (SST decrease) between rest and symptom-limited exercise and between rest and 1 and 5 mins postexercise recovery.

RESULTS

The average number of epicardial coronary segments analyzed per patient was 12. The mean diameter averaged 2.78 mm; the minimal diameter, 2.01 mm. The mean percentage coronary stenosis averaged 29.6% and the most severe averaged 62.9%. sigma ST decrease averaged -5323 microV.s between rest and peak exercise and recovered slowly, averaging -5117 microV.s at 1 min postexercise and -4562 microV.s at 5 mins. No QCA measure correlated with any ECG variable (range of r, 0.002 to -0.179; not significant).

CONCLUSIONS

Among CAD patients there are no close, or causal, relations between angiographic measures of anatomic epicardial coronary atherosclerosis and ECG functional measures of exercise-induced myocardial ischemia. These data suggest that demonstrated values of stress ECG and coronary angiography for the prediction of clinical risk in CAD patients are largely independent of each other.

Prompt improvement of left ventricular function and preservation of topography with combined reperfusion and intravenous nitroglycerin in acute myocardial infarction

Reperfusion alone during acute myocardial infarction (AMI) preserves left ventricular (LV) topography but causes 'stunning', with delayed or no recovery of function. To determine whether adjunctive intravenous nitroglycerin (NTG) accelerates functional recovery, we prospectively measured function and topography by repeated two-dimensional echocardiography between 1 day and 6 months in 5 groups of patients (n = 73) with a first AMI: placebo (group 1), NTG alone (group 2), NTG combined with successful reperfusion after 4 h (group 3) or failed reperfusion (group 4), and successful reperfusion alone (group 5). Asynergy decreased promptly (p < 0.001) and ejection fraction improved (p < 0.001) between day 1 and 6 months in groups 2 and 3 compared to baseline and groups 1, 4 and 5. Infarct expansion and thinning found in group 1 were prevented in groups 2, 3, 4 and 5. Diastolic volume increased in the anterior subgroup 1 but not 2, 3, 4 and 5. This is the first demonstration that reperfusion combined with adjunctive NTG produces earlier, greater and persistent recovery of LV function in addition to attenuation of remodeling in patients after AMI.