Evaluation of a Doppler-Derived Index Combining Systolic and Diastolic Left Ventricular Function in Acute Myocardial Infarction

The prognostic value of Tei index in acute myocardial infarction: a systematic review

Background

Echocardiographic evaluation of left ventricular ejection fraction (LVEF) is used in the risk stratification of patients with an acute myocardial infarction (AMI). However, the prognostic value of the Tei index, an alternative measure of global cardiac function, in AMI patients is not well established.

Methods

We conducted a systematic review, using MEDLINE and EMBASE, to evaluate the prognostic value of the Tei index in predicting adverse outcomes in patients presenting with AMI. The data was collected and narratively synthesised.

Results

A total of 16 studies were including in this review with 2886 participants (mean age was 60 years from 14 studies, the proportion of male patients 69.8% from 14 studies). Patient follow-up duration ranged from during the AMI hospitalisation stay to 57.8 months. Tei index showed a significant association with heart failure episodes, reinfarction, death and left ventricular thrombus formation in 14 out of the 16 studies. However, in one of these studies, Tei index was only significantly predictive of cardiac events in patients where LVEF was <40%. In two further studies, Tei index was not associated with predicting adverse outcomes once LVEF, left ventricular end-systolic volume index and left ventricular early filling time was taken into consideration. In the two remaining studies, there was no prognostic value of Tei index in relation to patient outcomes.

Conclusions

Tei index may be an important prognostic marker in AMI patients, however, more studies are needed to better understand when it should be used routinely within clinical practice.

Isoproterenol-induced myocardial injury: a systematic comparison of subcutaneous versus intraperitoneal delivery in a rat model

INTRODUCTION

Isoproterenol (ISO)-induced myocardial injury is widely used as an experimental animal model; however, the optimal route of delivery, i.e., subcutaneous (SC) versus intraperitoneal (IP) has not been clarified. We systematically compared changes in cardiac function (echocardiography, Doppler and strain imaging) and exercise capacity induced by ISO via SC versus IP delivery.

METHODS

Twelve rats were used in this study and classified into three groups: Control (n = 2), SC-ISO (n = 5), and IP-ISO (n = 5), each receiving serial injections of ISO (100 mcg/kg) for 5 days (days 1-5). All rats underwent echocardiographic analysis of left ventricular function and functional capacity (FC) assessment on a treadmill protocol at baseline and post treatment. Hearts were excised and weighed at the end of the study.

RESULTS

Left ventricular (LV) systolic and diastolic dysfunctions were adequately induced by both SC and IP delivery: > or =13% reduction in fractional shortening, > or =12% increase in wall motion score index, and > or =35% increase in myocardial performance index; > or =49% increase in E/A ratio; > or =9% decline in anterior wall tissue velocity; > or =12% decline in circumferential and radial tissue strain and strain rates; > or =20% decline in FC; and > or =40% increase in echocardiographic LV mass and gross heart weight in both groups.

CONCLUSION

Short-duration ISO administration with serial injections via SC and IP routes induces significant myocardial dysfunction and impairs FC with few differences between both modalities.

Independent prognostic importance of a restrictive left ventricular filling pattern after myocardial infarction: an individual patient meta-analysis: Meta-Analysis Research Group in Echocardiography acute myocardial infarction

BACKGROUND

Restrictive mitral filling pattern (RFP), the most severe form of diastolic dysfunction, is a predictor of outcome after acute myocardial infarction (AMI). Low power has precluded a definite conclusion on the independent importance of RFP, especially when overall systolic function is preserved. We undertook an individual patient meta-analysis to determine whether RFP is predictive of mortality independently of LV ejection fraction (LVEF), end-systolic volume index, and Killip class in patients after AMI.

METHODS AND RESULTS

Twelve prospective studies (3396 patients) assessing the relationship between prognosis and Doppler echocardiographic LV filling pattern in patients after AMI were included. Individual patient data from each study were extracted and collated into a single database for analysis. RFP was associated with higher all-cause mortality (hazard ratio, 2.67; 95% CI, 2.23 to 3.20; P<0.001) and remained an independent predictor in multivariate analysis with age, gender, and LVEF. The overall prevalence of RFP was 20% but was highest (36%) in the quartile of patients with lowest LVEF (<39%) and lowest (9%) in patients with the highest LVEF (>53%; P<0.0001). RFP remained significant within each quartile of LVEF, and no interaction was found for RFP and LVEF (P=0.42). RFP also predicted mortality in patients with above- and below-median end-systolic volume index (1575 patients) and in different Killip classes (1746 patients). Importantly, when diabetes, current medication, and prior AMI were included in the model, RFP remained an independent predictor of outcome.

CONCLUSIONS

Restrictive filling is an important independent predictor of mortality after AMI regardless of LVEF, end-systolic volume index, and Killip class.

Individual patient meta-analyses of restrictive diastolic filling pattern and mortality in patients post acute myocardial infarction and in patients with chronic heart failure

BACKGROUND AND OBJECTIVE

Doppler echocardiographic assessment of diastolic filling provides a non-invasive estimate of left ventricular (LV) filling pressure and the most advanced diastolic filling grade, the restrictive filling pattern (RFP), has been linked to prognosis in patients post acute myocardial infarction (AMI) and with heart failure (HF). There remains some uncertainty about the prognostic role of RFP in patients with varied levels of systolic function. The objective of this collaboration is to determine whether the presence of RFP offers additional prognostic information over LV systolic function, symptoms or other clinical factors in patients post AMI or with HF.

METHODS

The Meta-analysis Research Group in Echocardiography (MeRGE) has been established in order to test this through two individual patient meta-analyses. Prospective studies that enrolled patients with either established HF or post AMI and included Doppler-echocardiography and outcome data will be merged into two large datasets (3739 AMI patients and 3540 HF patients) in order to evaluate the independent effects of RFP upon total and cardiovascular mortality using Kaplan-Meier survival analysis methods and Cox proportional hazards model for multi-variate analysis. Survival will be examined within different bands of LV systolic function based upon ejection fraction (EF).

IMPLICATIONS

This unique dataset will provide a very large cohort of patients, which will be adequately powered to provide new and prognostically important information to further aid risk stratification in these two high-risk patient groups.

Restrictive Filling Pattern is a Powerful Predictor of Heart Failure Events Postacute Myocardial Infarction and in Established Heart Failure: A Literature-Based Meta-Analysis

BACKGROUND

Two recent literature-based meta-analyses revealed that restrictive filling pattern (RFP) was associated with a 4-fold increase in the risk of death in patients with heart failure (HF) and postacute myocardial infarction (AMI). This similar but unique analysis evaluated the link between RFP and morbidity.

METHODS AND RESULTS

Prospective echocardiographic studies of patients post-AMI and with HF that reported HF morbidity were identified. Events (post-AMI: development of HF; HF: HF readmission) were compared between patients with and without RFP in both patient groups. Review Manager version 4.2.7 software was used for the analysis. Twelve post-AMI studies (1286 patients, 271 events) and 5 HF studies (647 patients, 176 events) were identified. RFP was associated with HF readmission in the HF patients (OR 2.96 [2.02-4.33] and development of HF post-AMI (OR 10.10 [7.02-14.51]). The event rate in the RFP group was the same regardless of disease category (49% post-AMI, 42% HF); however, RFP was less prevalent in the post-AMI group (22% versus 39%).

CONCLUSIONS

This literature-based meta-analysis confirms that RFP is a powerful predictor of HF hospitalization in patients with HF and especially the development of HF post-AMI. This is an important prognostic sign and should be incorporated into routine clinical practice.

Restrictive diastolic filling predicts death after acute myocardial infarction: systematic review and meta-analysis of prospective studies

OBJECTIVE

To determine, through a systematic review and meta-analysis, the magnitude of the survival deficit associated with a restrictive filling pattern after acute myocardial infarction (AMI).

METHODS

Online databases were searched for prospective echocardiography outcome studies of patients after AMI. All authors were contacted to seek confirmation of their data. Restrictive filling was compared with all non-restrictive filling patterns. Review Manager Version 4.2.7 software was used for analysis.

RESULTS

3855 patients in 16 studies were identified. Follow up varied from two weeks to five years (> 1 year, 10 studies; and > 4 years, four studies). 776 (20%) of patients had a restrictive filling pattern at baseline. 580 patients died (247 in the restrictive group), and the overall odds ratio for death (restrictive filling worse) was 4.10 (95% confidence interval 3.38 to 4.99).

CONCLUSIONS

Mortality is about four times higher in patients with a restrictive filling pattern than in those with non-restrictive filling patterns after AMI. Echocardiographic assessment of diastolic filling pattern is an important part of the echocardiographic assessment of patients after myocardial infarction and provides important prognostic information about such patients.

Validation of echocardiographic methods for assessing left ventricular dysfunction in rats with myocardial infarction

The rat infarct model is widely used in heart failure research, but few echocardiographic indexes of left ventricular (LV) function are validated in this model. Accordingly, the objective of this study was to validate a 13-segment LV wall motion score index (WMSI) and the myocardial performance index (MPI) in infarcted rats. Twenty-nine male Wistar rats underwent left coronary artery ligation or sham operation and were evaluated with two-dimensional and Doppler flow echocardiography 8 wk later. After echocardiography, invasive indexes were obtained using a high-fidelity catheter. WMSI and MPI were correlated with the invasive and noninvasive measurements of LV function. WMSI and MPI significantly correlated directly with end-diastolic pressure (r=0.72 and 0.42 for WMSI and MPI, respectively) and the time constant of isovolumic relaxation (r=0.68 and 0.48) and inversely with peak rate of rise of LV pressure (+dP/dt; r=-0.68 and -0.50), peak rate of decline in LV pressure (r=-0.57 and -0.44), LV developed pressure (r=-0.58 and -0.42), area fractional shortening (r=-0.85 and -0.53), and cardiac index (r=-0.74 and -0.74). Stepwise linear regression analyses revealed that LV end-diastolic pressure, +dP/dt, area fractional shortening, and cardiac index were independent determinants of WMSI (r=0.994) and that cardiac index and +dP/dt were independent determinants of MPI (r=0.781). We conclude that the 13-segment WMSI and MPI are reproducible and correlate strongly with established echocardiographic and invasive indexes of systolic and diastolic function. These findings support the use of WMSI and MPI as indexes of global LV function in the rat infarction model of heart failure.