[Troponine T as possible myocardial injury marker. Its application in myocardial stunning and silent ischemia]

Predictors and prognostic value of myocardial injury following stent implantation

BACKGROUND

Troponin I concentrations are frequently elevated following percutaneous coronary intervention (PCI) even in procedures without complications and are considered, by some, as predictive of long-term morbidity and mortality. We assessed whether post-PCI troponin I concentrations bore any relationship to clinical, angiographic and in-laboratory minor adverse events indicative of myocardial injury and evaluated, in follow-up, whether these levels are useful as a predictive markers of adverse events.

METHODS

Patients (n=147) who were scheduled for PCI for stent placement were prospectively studied. In-laboratory events recorded were protracted chest pain, electrocardiographic changes, slow flows, dissections and lateral branch affectation. Troponin I and creatinine kinase MB fraction (CK-MB) mass were measured at baseline and post-procedure. Mean clinical follow-up was for 10.4+/-3.6 months.

RESULTS

During PCI, at least one adverse event occurred in 34% of patients and, in 38% of them, there was an elevation of troponin I as compared to 5.1% of those patients without any adverse event (relative risk=7.4; P<0.001). Elevation of troponin I concentrations occurred in 16.3% of all patients, 79.2% associated with an AE. CK-MB was elevated in 15.6% of patients. On multivariate analysis, protracted chest pain, lateral branch involvement and slow flow remained statistically significant in relation to post-procedure elevations of troponin I concentrations. Clinical follow-up showed a poorer prognosis in patients who had had elevated troponin I concentrations.

CONCLUSIONS

In-laboratory adverse event predict elevated post-procedure troponin I concentrations which are associated with myocardial injury. These elevations, in turn, predict poorer medium-term clinical outcomes.

Myocardial stunning during abdominal hysterectomy in a healthy woman

We report a case of myocardial stunning in a healthy patient. During gynecologic surgery, two brief episodes of asystole occurred. Following resuscitation there was a short period of severe hypertension and tachycardia. Electrocardiographic changes and elevations in troponin T and creatine-kinase-MB were observed. Angiography revealed normal coronary arteries and multiple areas of hypokinesis. Within 2 weeks, all abnormal values had returned to normal and the patient underwent an uneventful surgery.

[Prognostic value of troponin T in hospitalized patients with angina or non-ST-segment elevation myocardial infarction]

INTRODUCTION AND OBJECTIVES

Cardiac troponins are highly specific and sensitive for detecting minimal myocardial damage. The aim of our study was to determine the prognostic value of troponin T levels in patients hospitalized for suspected angina or myocardial infarction without ST-segment elevation.

PATIENTS AND METHOD

We recorded the frequency of death, acute myocardial infarction, heart failure, or need for coronary revascularization in the three months after the onset of symptoms in 346 consecutive patients admitted for suspected acute coronary syndrome, excluding those who developed myocardial infarction with persistent ST-segment elevation.

RESULT

. Serum troponin T levels were > or = 0.1 ng/ml in 133 patients (troponin T positive group) and lower in 213 patients (troponin T negative group). The relative risk (RR) and 95 percent confidence intervals (95% CI) of individual and grouped events for the troponin T positive group were 3.2 (95% CI, 1.4-7.3; p = 0.006) for death; 2.8 (95% CI, 1.43-5.51; p = 0.003) for death or myocardial infarction; and 2.8 (95% CI, 1.6-5.0; p < 0.001) for death, myocardial infarction or heart failure. Diabetes mellitus and troponin T levels > or = 0.1 ng/ml had independent prognostic value after adjusting for age, sex, and electrocardiographic changes; with RR 2.5 (95% CI, 1.01-5.9) for death, myocardial infarction or heart failure.

CONCLUSIONS

The prognosis of patients hospitalized for chest pain who do not immediately develop transmural necrosis depends on serum troponin T levels at hospital admission. Troponin T levels > or = 0.1 ng/ml almost triple the risk of major events in the three months after the acute episode. The prognostic value of troponin T is independent of age, sex, presence of diabetes mellitus, and electrocardiographic changes.

[Cardiac troponin I in perioperative myocardial infarction after coronary artery bypass surgery]

BACKGROUND AND AIMS

Myocardial infarction after coronary artery bypass grafting is a serious complication and one of the most common causes of perioperative morbidity and mortality. The present study was designed to determine the relevance of serum cardiac troponin I as a specific diagnostic marker for perioperative myocardial infarction.

METHODS

A cohort of 64 patients undergoing coronary artery bypass grafting was enrolled for prospective study. Postoperative blood samples were extracted and analyzed for total creatine kinase (CK), CKMB and cardiac troponin I activity. Perioperative infarction was defined as the development of new Q waves in the postoperative electrocardiogram together with congruent regional wall motion abnormalities in the echocardiogram and CK values greater than 400 IU/l with MB fraction greater than 40 IU/l.

RESULTS

Perioperative infarction occurred in 12 patients. Higher cardiac troponin I values were observed in patients experiencing perioperative myocardial infarction than in those without infarction (p < 0.001). Cardiac troponin I values higher than 12 ng/ml 10 h after release of the aortic clamp best detected the presence of perioperative myocardial infarction, with an area under the characteristic receiver operating curve of 0.91 (95% CI, 0.82-0.97), a sensitivity of 90.9%, and a specificity of 88.5%. The mean stay in the intensive care unit was significantly longer for patients who suffered perioperative myocardial infarction (6.5 8.6 days) than for patients without perioperative infarction (4.7 7.5 days) (p < 0.005).

CONCLUSIONS

Cardiac troponin I elevation appears to be an early, specific marker for the diagnosis of perioperative myocardial infarction after coronary artery bypass grafting.