Independent prognostic value of the extent and severity of systolic wall thickening abnormality at infarct site after thrombolytic therapy

Serum apolipoprotein B is inversely associated with eccentric left ventricular hypertrophy in peritoneal dialysis patients

OBJECTIVES

The study aimed to examine the relationship of serum apolipoprotein B level with left ventricular (LV) structural and functional characteristics, in particular, LV remodeling parameters in peritoneal dialysis (PD) patients.

METHODS

A total of 182 patients with end-stage renal disease (ESRD) receiving PD were identified. Conventional echocardiography was performed for each patient, and echocardiographic characteristics were analyzed according to apo B quartile groups. Multivariate linear regression models were used to determine the associations between serum apo B and LV remodeling indices.

RESULTS

A high serum apo B level was significantly related to the reduction in left atrium dimension (r = - 0.20, P = 0.011), LV dimensions (end-diastolic: r = - 0.27, P = 0.001; end-systolic: r = - 0.24, P = 0.003), peak velocities of early filling divided by peak velocities of atrial filling (r = - 0.38, P < 0.001), and LV volumetric dimension (end-diastolic: r = - 0.27, P < 0.001; end-systolic: r = - 0.28, P < 0.001). After adjustment for clinical confounding factors, the effect of serum apo B on LV eccentric remodeling modestly weakened but remained statistically significant (P = 0.038), while other associations were not significant. In multivariate linear regression analysis, conventional lipid profiles were not significantly associated with LV eccentric remodeling, whereas serum apo B was an independent determinant of LV dilatation (β: - 42.10, 95% CI - 74.82 to - 9.38, P = 0.012).

CONCLUSIONS

Serum apo B was significantly and inversely associated with LV dilatation, independently of conventional lipids and other CV risk factors in our ESRD patients undergoing PD. It suggested that low serum apo B level could be a powerful risk marker for eccentric left ventricular geometry remodeling and could be potentially used to risk-stratify PD patients.

Increased fibrosis and progression to heart failure in MRL mice following ischemia/reperfusion injury

The cardiac regenerative capacity of MRL/MpJ mouse remains a controversy. Although the MRL mouse has been reported to exhibit minimal scarring and subsequent cardiac regeneration after cryoinjury of the right ventricle, multiple studies have been unable to replicate this cardiac regenerative capacity after both cryogenic and coronary ligation cardiac injury. Therefore, we evaluated the cardiac regenerative wound-healing response and functional recovery of MRL mice compared to C57 mice, in response to a clinically relevant left ventricular (LV) coronary ligation. Male MRL/MpJ+/+ and C57BL/6 mice underwent left coronary artery ligation followed by reperfusion. Cardiac function was evaluated by echocardiography [LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), LV mass, wall thickness] at 24 hours post-ischemia and weekly for 13 weeks thereafter. Hearts were also analyzed histologically for individual cardiomyocyte hypertrophy and cardiac fibrosis. Our results show that contrary to prior reports of cardiac regenerations, MRL mice progress to heart failure more rapidly following I/R injury as marked by a significant decrease in LVEF, increase in LVEDV, LV mass, individual myocyte size, and fibrosis in the post-ischemic myocardium. Therefore, we conclude that MRL mice do not exhibit regeneration of the LV or enhanced functional improvement in response to coronary ligation. However, unlike prior studies, we matched initial infarct size in MRL and C57 mice, used high frequency echocardiography, and histological analysis to reach this conclusion. The prospect of cardiac regeneration after ischemia in MRL mice seems to have attenuated interest, given the multiple negative studies and the promise of stem cell cardiac regeneration. However, our novel observation that MRL may possess an impaired compensated hypertrophy response makes the MRL mouse strain an interesting model in the study of cardiac hypertrophy.

Myocardial contrast echocardiography accurately reflects transmurality of myocardial necrosis and predicts contractile reserve after acute myocardial infarction

BACKGROUND

Both myocardial contrast echocardiography (MCE) and cardiovascular magnetic resonance (CMR) can identify myocardial necrosis after acute myocardial infarction (AMI). However, transmural extent of infarction (TEI) correlates of myocardial perfusion by MCE after AMI are unknown. We sought to ascertain the ability of MCE to (1) predict TEI as defined by contrast-enhanced CMR and (2) to compare the relative accuracy of these techniques to predict contractile reserve late after AMI.

METHODS

MCE and CMR were performed in 42 patients with AMI 7 to 10 days after thrombolysis. Contractile reserve with low-dose dobutamine was evaluated 12 weeks after revascularization.

RESULTS

Both qualitative (myocardial contrast intensity) and quantitative MCE [peak contrast intensity, microbubble velocity (beta), and myocardial blood flow] showed a significant (P < .0001) inverse relationship with increasing TEI. However, beta was the single best predictor of TEI (P = .002). Both qualitative MCE and CMR predicted contractile reserve similarly (area under receiver operating characteristic curve were 0.84 and 0.80, respectively). Qualitative and quantitative MCE parameters as well as CMR correlated significantly with the degree of contractile reserve (P < .001). Multiple logistic regression analysis using clinical, electrocardiographic, MCE, and CMR parameters showed that both MCE (OR = 0.03, 95% CI 0.01-0.10, P < .001) and CMR (OR = 0.11, 95% CI 0.04-0.26, P < .001) are independent predictors of contractile reserve. The most discriminative quantitative parameters for prediction of contractile reserve were microbubble velocity (P < .001) and myocardial blood flow (P = .001) assessed by MCE.

CONCLUSION

MCE reflects the transmural extent of AMI as assessed by CMR. Both techniques predict contractile reserve.

Is echocardiography a valid tool to screen for left ventricular systolic dysfunction in chronic survivors of acute myocardial infarction? A comparison with radionuclide ventriculography

OBJECTIVE

To assess the accuracy of echocardiography with Simpson's apical biplane method in screening for left ventricular systolic dysfunction (LVSD) in patients six months after acute myocardial infarction (AMI) as compared with radionuclide ventriculography by assessing the proportion of clinically significant errors that occur with echocardiography.

DESIGN

Comparison of results of echocardiography and radionuclide ventriculography in assessing left ventricular ejection fraction among patients six months after AMI.

SETTING

District general hospital.

PATIENTS

86 patients thrombolysed for AMI at six month follow up.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Correlation coefficients, mean differences, 95% limits of agreement, and differences of clinical significance between left ventricular ejection fraction on echocardiography and on radionuclide ventriculography.

RESULTS

The correlation coefficient between techniques was 0.90, mean difference 1% (p = 0.04), and 95% limits of agreement -13.0% to 10.3%. Only one patient (1.2%, 0.0% to 6.3%) was classified as having normal systolic function on one imaging modality but significant LVSD on the other. Overall accuracy between the two techniques was 86%, kappa value of agreement 0.78.

CONCLUSION

Echocardiography is a valid tool to screen for LVSD in patients six months after AMI, accurately differentiating normal from abnormal systolic function and showing excellent agreement with radionuclide ventriculography. This study supports the use of echocardiography in screening for LVSD in chronic stable patients after AMI or alternative high risk patients, with few differences of major clinical significance likely to occur.

Is left ventricular diastolic function an independent marker of prognosis after acute myocardial infarction?

BACKGROUND

In addition to clinical risk markers, indices of left ventricular (LV) systolic function are valuable prognostic markers after acute myocardial infarction (MI). Previous studies have also suggested that LV diastolic function may contribute with prognostic information. The present study assessed whether this assumption applies to a large population of patients with acute MI who underwent thrombolytic therapy.

METHODS AND RESULTS

520 out of 608 patients participating in the ATTenuation by Adenosine of Cardiac Complications (ATTACC) study, with an ST-elevation acute MI underwent two-dimensional and Doppler echocardiographic examination at 4 (range 2-10) days after admission. During the follow-up period of 31 (S.D. +/- 11) months, cardiovascular death occurred in 57 (11%) patients, nonfatal acute MI occurred in 77 (15%), and 124 (24%) patients suffered a combined cardiovascular end-point (either nonfatal acute MI or cardiovascular death). Univariate regression analysis showed that all indices of LV systolic function predicted cardiovascular death and combined cardiovascular end-points. Regarding LV diastolic function only a restrictive filling pattern predicted cardiovascular death. In a multistep multivariate regression analysis in which the variables were introduced in a hierarchic order age, history of systemic hypertension, wall motion score index (WMSi), and history of previous MI and diabetes mellitus were independent predictors of cardiovascular death. A history of systemic hypertension or congestive heart failure were independent predictors of nonfatal acute MI, while a history of systemic hypertension, wall motion score index and diabetes mellitus independently predicted combined cardiovascular end-points.

CONCLUSIONS

The results of this study confirmed that clinical risk indicators and LV systolic function were the most important independent predictors of cardiovascular death and combined cardiovascular end-points. LV diastolic function assessed by Doppler-echocardiography did not provide additional prognostic information.

Reliability of reporting left ventricular systolic function by echocardiography: a systematic review of 3 methods

BACKGROUND

An accurate assessment of left ventricular (LV) systolic function is of central importance to the diagnosis and management of heart failure. Echocardiography is currently the technique most widely used for this purpose.

METHODS

A systematic review was performed of the evidence for the accuracy of 3 echocardiographic methods--Simpson's rule, wall motion index (WMI), and subjective visual assessment--compared with radionuclide or contrast ventriculography for the assessment of LV ejection fraction (LVEF).

RESULTS

Twenty-five studies were identified in which data on agreement between echocardiography and reference methods were obtainable. A further 18 studies provided correlation data alone. For Simpson's rule, Bland-Altman limits of agreement (95% CI) ranged from LVEF +/-7% to +/-25% (median +/-18%); for WMI +/-13% to +/-20% (median +/-16%); and for subjective visual assessment +/-16% to +/-24% (median +/-19%). Subject echogenicity, the nature of underlying disease, and the use of additional imaging technology, including secondary harmonic imaging and contrast agents, is likely to influence the accuracy of different methods. No method appears to systematically under- or overestimate LVEF to any major extent.

CONCLUSION

These findings have important implications for the investigation of heart failure and for the practice and reporting of echocardiography.

Impact of early changes in left ventricular filling pattern on long-term outcome after acute myocardial infarction

BACKGROUND

In patients with heart failure due to chronic ischemic heart disease improvement of diastolic function indicates improved survival and a reduced morbidity, but whether this is also the case after acute myocardial infarction is not known.

METHODS

To assess the prognostic importance of changes in left ventricular filling pattern, assessed with mitral deceleration time and colour M-mode flow propagation velocity, on cardiac death and readmission due to heart failure serial Doppler echocardiography was carried out in 103 patients with a first myocardial infarction. Based on echocardiography on hospital admission and after 1 month, patients were divided into three groups: group A (n=29) comprised patients with normal filling at either examination, group B (n=29) comprised patients with improvement of initially abnormal filling, and group C (n=45) patients with deterioration or no change of an abnormal filling pattern.

RESULTS

One-year survival free of cardiac death or hospitalisation for heart failure was 97% in group A, 86% in group B and 64% in group C (P<0.0001). In Cox analysis persistence of abnormal filling or deterioration of left ventricular filling was still a predictor of the combined endpoint (risk ratio 4.4, 95% CI 1.8-12.0, P=0.003) after adjustment of LV filling on admission, left ventricular systolic function and clinical variables. Serial analyses of left ventricular systolic function demonstrated a significant improvement after 1 year in ejection fraction in groups A and B, whereas ejection fraction remained unchanged in group C.

CONCLUSION

Patients with a persistently abnormal or a deterioration of left ventricular filling pattern as opposed to improved or normal filling are at increased risk of cardiac death and readmission due to heart failure after acute myocardial infarction.

Contrast echocardiography and acute coronary syndromes

Since microvascular perfusion parallels myocardial viability, myocardial contrast echocardiography (MCE) can provide informations regarding myocardial recovery after an acute myocardial infarction (AMI). Recent studies have demonstrated the role of MCE to evaluate the value of perfusion and function during rest and dobutamine stress echo in patients early after AMI in terms of risk stratification and management of these patients.

A prospective comparison of echocardiographic wall motion score index and radionuclide ejection fraction in predicting outcome following acute myocardial infarction

OBJECTIVE

To characterise echocardiographic wall motion score index (WMSI) as a surrogate measure of left ventricular ejection fraction (EF) following acute myocardial infarction (AMI) and to compare its prognostic value with that of EF measured by radionuclide ventriculography (RNV).

DESIGN

A prospective study to compare baseline echocardiographic WMSI with RNV EF in consecutive patients thrombolysed for AMI, both performed on the same day before discharge, and their relative prognostic values in predicting cardiac events.

SETTING

District general hospital coronary care unit and cardiology department.

PATIENTS

120 consecutive patients free of exclusion criteria thrombolysed for AMI and followed up for a mean (SD) of 13 (10) months.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Correlation coefficients and receiver operating characteristic curve analyses plus cardiac event rates at follow up between RNV EF and echocardiographic WMSI.

RESULTS

WMSI correlated well with RNV EF. The best corresponding WMSIs for EFs 45%, 40%, and 35% were 0.6, 0.8, and 1.1, respectively. There were 42 cardiac events during follow up. Although both RNV EF and WMSI were strong univariate predictors of cardiac events, only WMSI independently predicted outcome in a multivariate model. All three WMSI cut offs significantly predicted events, while an RNV EF cut off of </= 45% v > 45% failed to reach significance.

CONCLUSIONS

Although both RNV and echocardiographic WMSI strongly predicted cardiac outcome, WMSI, a cheaper and more readily available technique, is more discriminatory, especially in cases of mild left ventricular dysfunction following AMI.

Usefulness of the severity and extent of wall motion abnormalities as prognostic markers of an adverse outcome after a first myocardial infarction treated with thrombolytic therapy

The prognostic value of wall motion score index (WMSI), assessed at predischarge after a first acute myocardial infarction (AMI) in the thrombolytic era, is still not well known. One-hundred forty-four consecutive patients with a first AMI treated with thrombolytic therapy underwent exercise testing and echocardiography at rest before discharge and were followed-up for a mean period of 18 months. During follow-up, there were 32 cardiac events (12 patients had cardiac deaths, 8 had unstable angina pectoris, 1 had nonfatal reinfarction, and 11 patients had congestive heart failure). The patients who experienced any cardiac event had a higher WMSI (1.67+/-0.15 vs. 1.30+/-0.16, p<0.0001), a higher end-systolic volume (75.1+/-34 vs. 59.5+/-22 ml, p<0.01), and a lower ejection fraction (47+/-16% vs. 55+/-10%, p<0.001) at predischarge than patients without events. The incidence of a positive predischarge exercise testing did not differ between patients with and without cardiac events (22% vs. 24%, p = NS). Multivariate Cox regression analysis, including clinical, exercise results, and echocardiographic parameters, showed that the most powerful predictor of a subsequent event was a resting WMSI > or =1.50 before discharge (chi-square 17.8, p<0.0001). Thus, in patients with a first AMI who underwent thrombolysis, the severity and extent of echocardiographically detected wall motion abnormalities are important independent predictors of cardiac events.

Role of Contrast Echocardiography for the Assessment of Left Ventricular Function

The endocardial border of the left ventricle is incompletely identified in at least 30% of patients at rest or during stress echocardiography during fundamental imaging. This may lead to inaccurate assessment of regional and global left ventricular function or may lead to further diagnostic imaging with another modality resulting in a higher cost of healthcare. The recent development of second generation ultrasound contrast agents has resulted in improved detection of endocardial border at rest and during stress fundamental echocardiography. This has been consistently shown in various clinical trials involving 702 patients using a new contrast agent, SonoVuetrade mark. Other studies with contrast agents have also shown improved accuracy for determining left ventricular ejection fraction and volumes. Although unenhanced tissue harmonic imaging itself improved the assessment of left ventricular function, contrast enhanced harmonic imaging has recently been shown to be more accurate; however, larger clinical studies are required to establish the value of harmonic contrast imaging for the assessment of left ventricular function.