Late Reperfusion (6-24 Hours After Onset) Improves Left Ventricular Function in Patients With Acute Myocardial Infarction

Survival and cardiac remodeling benefits in patients undergoing late percutaneous coronary intervention of the infarct-related artery: evidence from a meta-analysis of randomized controlled trials

OBJECTIVES

Our purpose was to perform a systematic review and meta-analysis of randomized trials comparing percutaneous coronary intervention (PCI) of the infarct-related artery (IRA) with medical therapy in patients randomized >12 h after acute myocardial infarction (AMI).

BACKGROUND

There is ongoing uncertainty about the risk-benefit ratio of late PCI in stable patients with AMI.

METHODS

PubMed, CENTRAL, and other databases were searched (July 2007). Studies were included if they compared PCI with medical management and randomized patients >12 h and up to 60 days after AMI, and were excluded if patients were hemodynamically unstable. Odds ratios (ORs) were pooled for dichotomous outcomes, with all-cause mortality as the primary end point. Left cardiac remodeling parameters were also pooled with generic inverse-variance weighting.

RESULTS

We retrieved 10 studies that enrolled 3,560 patients, with median time from AMI to randomization of 12 days (range 1 to 26 days), and follow-up of 2.8 years (42 days to 10 years). Randomization allocated 1,779 subjects to PCI and 1,781 to medical treatment. There were 112 (6.3%) and 149 (8.4%) deaths in the 2 groups, respectively, yielding significantly improved survival in the PCI group (OR 0.49 [95% confidence interval (CI) 0.26 to 0.94], p = 0.030). These benefits were associated with similarly favorable effects on cardiac remodeling, such as improved left ventricular ejection fraction in the PCI group (+4.4% change [95% CI 1.1 to 7.6], p = 0.009).

CONCLUSIONS

Percutaneous coronary intervention of the IRA performed late (12 h to 60 days) after AMI is associated with significant improvements in cardiac function and survival.

Multidetector row computed tomography can identify and characterize the occlusive culprit lesions in patients early (within 24 hours) after acute myocardial infarction

BACKGROUND

The reliable noninvasive assessment of occluded disrupted plaques and thromboses in culprit vessels could constitute an important step forward in risk stratification of patients early after acute myocardial infarction (AMI). However, noninvasive identification of patency of culprit vessels remains a challenging issue. This prospective study was designed to identify the occluded culprit vessels by multidetector row computed tomography (MDCT) and to compare the stenotic and occlusive culprit lesions by MDCT in patients early (within 24 hours) after AMI.

METHODS

We enrolled 62 patients with first Q-wave AMI (54 males). Multidetector row computed tomography was performed 16.5 +/- 7.1 hours after the onset of chest pain without any complication. Coronary angiography was done within 6 hours after MDCT. Patients were divided into 2 groups according to angiographic findings: stenotic group (35 patients) and occluded group (27 patients). The following MDCT data were collected: luminal artery stenosis, remodeling index, plaque burden, and lesion attenuation.

RESULTS

Compared to coronary angiography, MDCT detected occluded culprit vessels with sensitivity, specificity, negative predict value, and positive predict value of 92.6%, 88.6%, 93.9%, and 86.2%, respectively. Compared with the stenotic group, culprit lesions in the occlusive group had significantly longer length (18.9 +/- 9.7 vs 11.9 +/- 6.2 mm; P = .024) and higher MDCT lesion attenuation (38.8 +/- 15.6 vs 29.2 +/- 12.9 Hounsfield unit; P = .008). Multidetector row computed tomography attenuation was negatively correlated with thrombolysis in myocardial infarction flow (Spearman rho = -0.46; P < .001).

CONCLUSIONS

Multidetector row computed tomography could accurately and safely identify occluded culprit lesions in patients early after AMI, providing important information to aid in risk stratification.

Shunt between the ventricular chamber and coronary arteries preserves left ventricular function in acute myocardial infarction

It is controversial whether newly created channels made by transmyocardial laser revascularization are functionally significant, so the present study evaluated the shunt flow from the left ventricular (LV) cavity to the ischemic myocardium in 51 patients with acute myocardial infarction (AMI) caused by complete occlusion of the proximal left anterior descending coronary artery. All patients underwent left heart catheterization within 24 h of onset and all underwent successful coronary reperfusion using primary coronary angioplasty with no angiographic restenosis on follow-up coronary angiography (CAG). The presence of the LV shunt flow was evaluated by selective left CAG after successful reperfusion. The LV global ejection fraction (EF) and regional function (centerline method) were analyzed by ventriculography in both the acute and chronic phases. The patients were divided into the 3 groups (Group A, no LV shunt without collaterals, n=20; Group B, no LV shunt with collaterals, n=24; Group C, LV shunt with collaterals, n=7). There was no difference in the grade of collateral circulation between Groups B and C. The improvements in LVEF and regional function from the acute phase to the chronic phase were significantly greater in Group C than in Groups A and B. Not only collateral circulation but also LV shunt contributes to the functional recovery of infarct myocardium in patients with AMI.

Benefits of late reperfusion in the treatment of acute myocardial infarction

Early reperfusion of the infarct-related coronary artery is very much effective to treat the patients with acute myocardial infraction. However, there are many clinical as well as experimental evidences supporting the efficacy of late reperfusion therapy. In this article, effects of late reperfusion on mortality, left ventricular function, left ventricular dilatation and remodeling, or electrical stability were summarized. Also, the possible mechanisms for benefits of late reperfusion were discussed and the special role of epicardial rim bring about those benefits was emphasized.