Myocardial performance index for assessment of left ventricular outcome in successfully recanalised anterior myocardial infarction

Echocardiographic parameters to identify sickle cell patients with cardio-pathology

BACKGROUND

Sickle cell disease (SCD) affects millions of people and causes chronic hemolytic anemia leading to vasculopathies such as pulmonary hypertension and abnormalities in cardiac function that increase complications and mortality. It is therefore crucial to identify cardiac abnormalities in SCD. We aimed to assess the prevalence of echocardiographic parameters in SCD to help identify cardiopulmonary risk.

METHODS

Ninety-one patients (53% male), median age of 30, body surface area (BSA) of 1.79 m² , hemoglobin of 8.8 g/dL, and creatinine of 0.7 mg/dL identified. We retrospectively measured laboratory and echocardiographic parameters in patients with SCD : left ventricular (LV) dimensions, LV ejection fraction (LVEF), LV Myocardial Performance Index (MPI), LV Mass Index (MI), Left Atrial Volume Index (LAVI), Tricuspid Regurgitation Velocity (TRV), tricuspid annular plane systolic excursion (TAPSE), right heart dimensions.

RESULTS

Prevalence of left heart abnormalities was 32%: increased LV end-diastolic diameter (EDD), 78%: LV MPI, 21%: diastolic dysfunction, 38%: decreased LVEF, 24%: increased LVMI, and 47%: increased LAVI. Right heart abnormalities were 39%: TAPSE, 38%: increased TRV, and 59%: increased pulmonary systolic pressure (PASP). Multivariate logistic regression analysis was significant for increased LVMI and LAVI in those with hemoglobin ≤8 g/dL (odds ratio (OR) 7.4, 95% confidence interval (CI) 2.23-24.6, P = .001) and (OR 3.32, 95% CI 1.18-9.33, P = .023).

CONCLUSIONS

We confirmed increased prevalence of abnormal LVEDD, LVMI, diastolic function, LAVI, and PASP in SCD. In addition, we identified abnormal LV MPI (78%), TAPSE (29%). These parameters may be useful and readily accessible echocardiographic prognostic tools in this population.

Interval Changes in Myocardial Performance Index Predict Outcome in Severe Sepsis

OBJECTIVES

Septic cardiomyopathy is a well-described consequence of septic shock and is associated with increased sepsis-related mortality. The myocardial performance index (MPI), a parameter derived from echocardiographic tissue Doppler measurements, allows for a more sensitive assessment of global cardiac function than do traditional metrics for cardiac function. The authors hypothesized that changes in left ventricular MPI in patients with severe sepsis would be associated with a higher 90-day mortality.

DESIGN

Prospective, observational study.

SETTING

Intensive care units of a tertiary medical center.

PARTICIPANTS

The study comprised 47 patients admitted with new diagnoses of severe sepsis or septic shock.

INTERVENTIONS

All patients underwent transthoracic echocardiograms with assessment of MPI at enrollment and 24 hours later. Hemodynamic data and information on sepsis-related mortality were collected. In the primary analysis, the association between change in MPI from enrollment to 24 hours and sepsis-related 90-day mortality was assessed.

MEASUREMENTS AND MAIN RESULTS

Of the 47 patients enrolled, 30 demonstrated an improvement in MPI from 0 to 24 hours ("improved" group), and MPI worsened in the remaining 17 patients ("worsened" group). Despite no significant differences in ejection fraction or severity of illness, the median MPI at enrollment in the "improved" group was higher than baseline values in the "worsened" group (p = 0.005). A worsening MPI over the 24-hour study interval was associated with increased mortality at 90 days (p = 0.04), which remained significant (hazard ratio 3.72; 95% confidence interval 1.12-12.41; p = 0.03) after adjusting for severity of illness (Acute Physiology and Chronic Health Evaluation II score), intravenous fluids, and vasopressor use.

CONCLUSIONS

In patients admitted to the intensive care unit with a diagnosis of severe sepsis or septic shock, a worsening MPI during the first 24 hours after intensive care unit admission was associated with higher 90-day mortality.

[Myocardial performance index: prediction and monitoring of remodeling and functioning of the left ventricle after first myocardial infarction]

INTRODUCTION

Dynamic changing of left ventricular geometry and contractile state after acute myocardial infarction is responsible for various aspects of left ventricular remodeling and dysfunction. A number of studies have shown that myocardial performance index allows prediction of acute myocardial infarction complications. The objective of our study was to determine the power of myocardial performance index to predict and assess the severity of left ventricular remodeling, systolic and diastolic dysfunction after acute myocardial infarction over the long term.

MATERIAL AND METHODS

Echocardiography was performed within the first week of hospitalization, after one, three and six months in 77 patients with first acute myocardial infarction. At the end of the study the patients were divided into group A and B with mild and severe left ventricular remodeling, respectively.

RESULTS

Myocardial performance index was significantly lower in group A compared to B, at the beginning (0.62 vs. 0.75; p = 0.002), and at the end of study (0, 60 vs. 0, 69; p = 0.004). After six months, 31% of study patients developed LV systolic dysfunction with prevalence in group B (56% vs. 19%, p = 0.002). Myocardial performance index > or = 0.70 at first week after acute myocardial infarction is a strong predictive parameter for extensive early and late left ventricular remodeling and systolic dysfunction (p < 0.05), but it is not a valuable predictor of diastolic failure.

DISCUSSION AND CONCLUSIONS

MPI obtained at first week of acute myocardial infarction was predictive for early and long term left ventricular remodeling and systolic dysfunction. Myocardial performance index had doubtful clinical use in assessing dynamics of remodeling and it was without clinical value in predicting diastolic function deterioration.

Paracrine effects of transplanted myoblasts and relaxin on post-infarction heart remodelling

In the post-infarcted heart, grafting of precursor cells may partially restore heart function but the improvement is modest and the mechanisms involved remain to be elucidated. Here, we explored this issue by transplanting C2C12 myoblasts, genetically engineered to express enhanced green fluorescent protein (eGFP) or eGFP and the cardiotropic hormone relaxin (RLX) through coronary venous route to swine with experimental chronic myocardial infarction. The rationale was to deliver constant, biologically effective levels of RLX at the site of cell engraftment. One month after engraftment, histological analysis showed that C2C12 myoblasts selectively settled in the ischaemic scar and were located around blood vessels showing an activated endothelium (ICAM-1-,VCAM-positive). C2C12 myoblasts did not trans-differentiate towards a cardiac phenotype, but did induce extracellular matrix remodelling by the secretion of matrix metalloproteases (MMP) and increase microvessel density through the expression of vascular endothelial growth factor (VEGF). Relaxin-producing C2C12 myoblasts displayed greater efficacy to engraft the post-ischaemic scar and to induce extracellular matrix re-modelling and angiogenesis as compared with the control cells. By echocardiography, C2C12-engrafted swine showed improved heart contractility compared with the ungrafted controls, especially those producing RLX. We suggest that the beneficial effects of myoblast grafting on cardiac function are primarily dependent on the paracrine effects of transplanted cells on extracellular matrix remodelling and vascularization. The combined treatment with myoblast transplantation and local RLX production may be helpful in preventing deleterious cardiac remodelling and may hold therapeutic possibility for post-infarcted patients.

Plain Computed Tomography for Assessment of Early Coronary Microcirculatory Damage After Revascularization Therapy in Acute Myocardial Infarction

BACKGROUND

Coronary microcirculatory damage is an important factor for the prognosis for acute myocardial infarction (MI) after revascularization. The myocardial enhancement area with contrast media infused during coronary revascularization therapy, detected by computed tomography (CT) just after revascularization, has been reported to correspond to the area of hemorrhagic infarction. The relationship between myocardial contrast enhancement and coronary microcirculatory damage was investigated in the present study.

METHODS AND RESULTS

Thirteen patients with acute anterior MI underwent successful coronary revascularization within 6 h of symptom onset were enrolled. The coronary flow velocity pattern was measured using a Doppler guidewire and chest CT assessments were performed immediately after coronary revascularization. The ratio of mean CT number of the highest-enhanced myocardial area and the lumen of the left ventricle was defined as a relative CT number. The relative CT number significantly correlated with coronary diastolic deceleration time (r=-0.78, p<0.002) and coronary diastolic deceleration rate (r=0.74, p<0.04). It also correlated with peak myocardial enzyme release in plasma.

CONCLUSION

Myocardial contrast enhancement detected using plain CT just after coronary reperfusion therapy implies coronary microcirculatory damage in acute MI. The relative CT number is useful in evaluating the impaired coronary microcirculatory state.

Value of the myocardial performance index in myocardial infarction

The myocardial performance index represents an easy and reproducible parameter of both systolic and diastolic left ventricular function for the risk stratification of patients following acute myocardial infarction.