Increasingly well-preserved left ventricular function in hospital survivors with acute myocardial infarction: effect of early and complete reperfusion strategy on left ventricular remodeling

Fibroblast growth factor 21 protects against pathological cardiac remodeling by modulating galectin-3 expression

BACKGROUND/AIMS

Fibroblast growth factor 21 (FGF21) plays a protective role in ischemia/reperfusion induced cardiac injury. However, the exact molecular mechanism of FGF21 action remains unclear. This study was designed the protective effect of FGF21 on the heart and its mechanism.

METHOD

Adenovirus vector expressing FGF21 or control β-galactosidase was injected into the myocardium of mice. Myocardial injury was observed by tissue staining and immunohistochemical staining. The expression level of caspases-3 and galectin-3 in myocardial cells were observed by immunoblotting. Then, hypoxia-induced cell model was established. Small interfering RNA (SiRNA) and plasmid were transfected into H9c2 using Lipofectamine 2000 reagent (Invitrogen). The expression levels of galectin-3, ECM and cystatin-3 in cells were observed by immunoblotting, and the relationship between fibroblast growth factor 21 and galectin-3 was analyzed.

RESULT

Cell test in vitro showed that FGF21 could inhibit apoptosis and decrease the expression of ECM (ColIaI, fibronectin, and alpha-SMA) under hypoxia. Western blot data showed that hypoxia-induced cell damage increased galectin-3 levels, while FGF21 decreased galactose lectin-3 levels. In addition, inhibition of galactose agglutinin-3 expression by siRNA enhanced the cardioprotective effect of FGF21, while overexpression of galectin-3 reduced the cardioprotective effect of fibroblast growth factor 21.

CONCLUSION

FGF21 may be a novel therapy for hypoxia-induced cardiac injury by regulating the expression of galectin-3.

Acute effect of primary PCI on diastolic dysfunction recovery in anterior wall STEMI - A non-invasive evaluation by echocardiography

BACKGROUND

It is well established fact that acute coronary occlusion leads to diastolic dysfunction, followed by systolic dysfunction when myonecrosis occur. It is also proven that primary percutaneous coronary intervention (PPCI) is an excellent therapy for ST elevation myocardial infarction (STEMI) to improve outcomes. However there is a paucity of information on efficacy of PPCI in improving diastolic function. Evaluation of the role of PPCI in improving diastolic dysfunction is required.

METHODS

61 patients with first anterior wall STEMI who underwent PPCI to left anterior descending artery were included. Echocardiographic evaluation was performed within 24 h of PPCI and then on day 15, 3 months and 6 months after PPCI. We evaluated the prevalence of diastolic dysfunction after PPCI and its recovery during 6 months along with effect of duration of chest pain on diastolic function.

RESULTS

54.1% of patients had diastolic dysfunction after PPCI whereas it was only 21.3% after 6 months (p value < 0.001). Diastolic function indices like deceleration time, isovolumic relaxation time, E wave, A wave, E/A ratio, left atrial volume and index improved statistically from baseline to 6 months except mitral E/e' ratio. As time required to achieve reperfusion increases (chest pain duration and D to B time) the incidence of residual diastolic dysfunction also increases (p value < 0.001). Patients with TIMI flow < III had more diastolic dysfunction (p value < 0.001).

CONCLUSIONS

Primary PCI improves diastolic dysfunction in patients with anterior wall STEMI over a period of 6 months. Time to achieve reperfusion and effectiveness of reperfusion have significant effect on diastolic dysfunction.

Equilibrium radionuclide angiography for evaluating the effect of facilitated percutaneous coronary intervention on ventricular synchrony in patients with acute myocardial infarction

BACKGROUND

It is unclear whether facilitated percutaneous coronary intervention (PCI) via a transradial approach therapy is preferable to primary PCI, with improved ventricular synchrony performance (VS), in Chinese patients.

METHODS AND RESULTS

The 152 patients with their first anterior acute myocardial infarction (AMI) were randomized to a primary PCI group or facilitated PCI group. In the 1(st) week and 6(th) month after AMI onset, the parameters of VS were measured by equilibrium radionuclide angiography with ventricular phase analysis. The rate of TIMI grade-3 flow in the infarct-related artery pre-PCI in the facilitated PCI group was higher than that in the primary PCI group (30.56% vs. 8.45%, P=0.001). At the 6(th) month post-AMI, the parameters of time to peak ejection rate, phase shift and peak phase standard deviation were lower than in the primary PCI group (P<0.05, respectively). The incidence of recurrent ischemia and new or worsening congestive heart failure post-AMI in the facilitated PCI group was significantly lower than that in the primary PCI group (2.78% vs. 9.86%, P=0.043; 2.78% vs. 12.68%, P=0.028).

CONCLUSIONS

Facilitated PCI via a transradial approach might significantly inhibit left ventricular remodeling and improve left ventricular function because of the complete, persistent patency of the infarct-related artery with few complications of vessel access and bleeding.

Erythropoietin in patients with acute coronary syndrome and its cardioprotective action after percutaneous coronary intervention

BACKGROUND

Erythropoietin (EPO) has been shown to have effects beyond hematopoiesis, such as prevention of cardiac apoptosis. The purpose of the current study is to examine the influence of the time-course change in the serum concentration of endogenous EPO on cardiac functions in the chronic phase in patients with acute coronary syndrome, who successfully achieved reperfusion by primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

The prospective study included 34 patients with angiographically documented coronary artery disease, including 24 patients with acute myocardial infarction (AMI) and 10 patients with unstable angina pectoris (UAP) who underwent successful PCI within 24 h from the onset. Serum EPO concentration significantly increased at Day 3 and Day 7 compared with that at Day 1 in the AMI group, and the level at Day 3 was significantly higher in the AMI group than in the UAP group. There were significant correlations between DeltaEPO and Delta left ventricular ejection fraction (LVEF) or Delta left ventricular end-diastolic volume index and between peak EPO concentration and DeltaLVEF.

CONCLUSIONS

These data showed the time-dependent increase of serum EPO in AMI patients after primary PCI, indicating its possible contribution to cardioprotective effect in the chronic phase.

Equilibrium radionuclide angiography for evaluating the effect of percutaneous coronary intervention on ventricular aneurysm formation and systolic synchrony in patients with acute myocardial infarction

Left ventricular aneurysm (LVA) after myocardial infarction often results in serious complications. So far, when the LVA happened is unclear. Furthermore, it is a question whether percutaneous coronary intervention (PCI) can change or reverse the formation of LVA? And the report about the long term follow-up was rare. So this study was to evaluate the time sequence of the formation of LVA through left ventriculography in large scale of consecutive acute myocardial infarction (AMI) patients and evaluate the influence of PCI at different time after AMI on the change of systolic synchrony through phase analysis of equilibrium radionuclide angiography. The change of serum brain natriuretic peptide (BNP) was also measured to investigate its association with LVA. And follow up to 3 years to record the major adverse cardiac events. Total of 326 consecutive patients of anterior AMI with LVA were enrolled into this study. All patients were divided into four groups according to the time 'onset to balloon': group A (<3 h), group B (> or =3 and < or =6 h), group C (>6 and < or =12 h) and group D (>1 week). The paradox volume image as well as the parameters of left ventricular function and systolic synchrony were measured by equilibrium radionuclide angiography at 1 week and 6th month after AMI. Plasma BNP was measured in different time after AMI. The major adverse cardiac events were recorded up to 3 years. At the 6th month after AMI, left ventricular ejection fraction, peak ejection rate and peak filling rate in group A, B and C were significantly increased than those in group D while phase shift and peak phase standard deviation were decreased significantly (P < 0.05, respectively). At 6th month after AMI, the paradox volume index in group A was lowered than that in group B, C, and D (P < 0.05, respectively). In 18th hour, 5th day and 24th week after AMI, the values of BNP in group D were higher than those in group A, B and C (P < 0.05, respectively). There was not significantly different between group B and group C. Within the 3rd year follow-up, the incidences of angina post-AMI and mortality in group A, B, and C were significantly lowered than those in group D (P < 0.05, respectively). The LVA can formate shortly after the AMI. The early, fully and permanently patency of infraction related artery can effectively inhibit the left ventricular remodeling process, prevent LVA formation, improve its function and prognosis.

Clinical implications of serial changes in ST-segment elevation after reperfusion in patients with anterior acute myocardial infarction

BACKGROUND

In patients with acute myocardial infarction (AMI), the relationship of serial changes in ST-segment elevation after reperfusion to left ventricular (LV) function remains unclear.

METHODS AND RESULTS

The study group comprised 164 patients with reperfused anterior AMI within 6 h of symptom onset. The sum of ST-segment deviation was calculated on admission (SigmaST-admission), and 1 h (SigmaST-1 h) and 24 h (SigmaST-24 h) after reperfusion. ST resolution was defined as a reduction in SigmaST-1 h of > or =50% as compared with SigmaST-admission. Patients were classified into 3 groups: group A, 82 patients with ST resolution in whom SigmaST-1 h > or = SigmaST-24 h; group B, 37 patients with ST resolution in whom SigmaST-1 h < SigmaST-24 h; group C, 45 patients without ST resolution. Peak creatine kinase were higher in groups B and C than in group A (4,578+/-2,176, 4,236+/-2,638, 2,222+/-1,926 mU/ml, p<0.01). At 6 months follow-up, the LV ejection fraction were lower in groups B and C than in group A (53+/-8, 54+/-12, 62+/-9%, p<0.01).

CONCLUSIONS

An increase in ST-segment elevation 1-24 h after reperfusion, despite ST resolution, is associated with a larger infarction and poorer LV function in patients with reperfused anterior AMI.

Clinical validity of longitudinal pre-ejectional myocardial velocity for identifying the transmural extent of viable myocardium: early after reperfusion of an infarct-related coronary artery

BACKGROUND

Positive longitudinal pre-ejectional velocity (+PEVL) was recently reported to be a reliable index of myocardial recovery early after successful revascularization in myocardial infarction (MI); that is, it recognizes the transmural extent of viable myocardium. The applicability of PEVL in the real-world clinical setting for identifying the transmural extent of viable myocardium in reperfused recent MI was assessed.

METHODS AND RESULTS

Using tissue Doppler imaging, the resting basal and mid myocardial PEVLs were determined within 3 days after revascularization in 41 consecutive patients with recent MI. Infarct thickness was semi-quantified using delayed gadolinium-enhanced magnetic resonance imaging (MRI) at baseline and at 6-month follow up to differentiate transmural from nontransmural MI. The proportion of segments showing the presence of +PEVL was not significantly changed as infarct thickness increased (p=0.2), with 66.2% having +PEVL even in segments involving >75% transmural infarction. Moreover, +PEVL was found in a large fraction of segments with akinesia (70.4%). Specificity and negative predictive value of +PEVL for assessing infarct nontransmurality were disappointingly low (32.0% and 26.9%, respectively). All of these results were not altered when the 6-month follow-up MRI was done.

CONCLUSIONS

+PEVL cannot be regarded as a reliable marker for predicting the transmural extent of viable myocardium in recent MI.

Relationship Between Peripheral Monocytosis and Nonrecovery of Left Ventricular Function in Patients With Left Ventricular Dysfunction Complicated With Acute Myocardial Infarction

BACKGROUND

Although ischemic heart failure is a major cause of mortality after acute myocardial infarction (AMI), the factors that may influence the nonrecovery of left ventricular function (LVF) after an AMI are still unclear. The aim of this study was to identify predictors of nonrecovery of LVF in patients with left ventricular (LV) dysfunction (defined as an echocardiographic ejection fraction (EF)<40%) complicated with AMI who undergo successful primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

LVF recovery was defined as improvement of LVEF more than 10% compared with baseline LVEF at follow-up. One hundred and eight patients with LV dysfunction after AMI were divided into 2 groups according to the LVF recovery at follow-up: patients with LVF recovery (n=64) vs patients without LVF recovery (n=44). The follow-up LVEF was measured at 8+/-4 months after PCI. Patients without LVF recovery were older (76+/-13 years vs 59+/-14 years, p=0.023) and the baseline peak monocyte count, creatine kinase, and troponin I levels were significantly higher in patients without LVF recovery than in patients with LVF recovery. Delta LVEF (follow-up LVEF-baseline LVEF) correlated with baseline peak monocyte count (r=-0.417, p<0.001), baseline peak creatine kinase (r=-0.269, p=0.005), and baseline peak troponin I levels (r=-0.256, p=0.007). Multivariate analyses showed that baseline peak monocyte count and old age were the independent predictors of nonrecovery of LVF (hazard ratio; 3.38, 95% confidence interval (CI): 1.16-5.43, p=0.012, and hazard ratio; 2.38, 95% CI: 1.09-4.87, p=0.025, respectively).

CONCLUSION

Peripheral monocytosis is associated with nonrecovery of LVF in patients with LV dysfunction complicating an AMI who underwent successful primary PCI. These results suggest an important role of monocytes in the expansion of the infarct and the development of chronic ischemic heart failure after reperfusion therapy.