Periprocedural Myocardial Injury: Pathophysiology, Prognosis, and Prevention

The definition and clinical implications of myocardial infarction occurring in the setting of percutaneous coronary intervention have been the subject of unresolved controversy. The definitions of periprocedural myocardial infarction (PMI) are many and have evolved over recent years. Additionally, the recent advancement of different imaging modalities has provided useful information on a patients' pre-procedural risk of myocardial infarction. Nonetheless, questions on the benefit of different approaches to prevent PMI and their practical implementation remain open. This review aims to address these questions and to provide a current and contemporary perspective.

Role of metabolic manipulator trimetazidine in limiting percutaneous coronary intervention-induced myocardial injury

BACKGROUND

Trimetazidine (TMZ) is a metabolic modulator that shifts substrate utilization from fatty acid to carbohydrates, thereby, increasing myocardial glucose oxidation and improving myocardial ischemia. We evaluated whether TMZ is effective in reducing myocardial injury after percutaneous coronary intervention (PCI).

METHODS

Patients with stable angina undergoing elective PCI were divided into two groups, one who received oral TMZ (35 mg BD) started 7 days before PCI (n = 48) and second who did not receive any TMZ (in addition to the standard therapy (n = 52)). Troponin-I (cTnI) and creatine kinase-MB (CK-MB) were measured before, 8, and 24 h after PCI. The primary end point was a difference in post-PCI cTnI and CK-MB levels (vs baseline). Frequency of cTnI release in the two groups, total amount of cTnI release, and difference in TIMI flow grade before and after the procedure were also assessed.

RESULTS

Baseline demographics in the groups were comparable. Despite similar baseline levels, post-procedural cTnI was lower at 8 h (0.13 vs 0.56 ng/ml, p = 0.03) and 24 h (0.2 vs 1.13 ng/ml, p = 0.004) in the TMZ group. Decline or no change in cTnI was significantly more common in the TMZ group (26% vs 2%, p < 0.01). Total cTnI released after PCI, as assessed by area under curve was significantly lower in the TMZ group (15.84 vs 3.32 ng h/ml, p = 0.005). Although CK-MB levels were also lower in the TMZ group, the difference was not statistically significant. Incidence of post-PCI TIMI 1 or 2 flow was significantly lesser in the TMZ group.

CONCLUSIONS

Oral TMZ started 7 days before PCI was effective in limiting PCI-induced myocardial injury with lower cTnI levels and higher prevalence of TIMI-3 flow.

High-dose atorvastatin reduces the risk of cardiovascular events in patients with percutaneous coronary intervention

We systematically searched in PubMed, Web of Science, Embase and China National Knowledge Infrastructure from the inception to March 31, 2017, identified relevant trials about efficacy of high-does Atorvastatin for patients with percutaneous coronary intervention. Twelve studies with the number of 2801 patients were included in the meta-analysis. Compared with control group, high-does Atorvastatin significantly reduced the risk of myocardial infarction in patients with percutaneous coronary intervention (Relative risk =0.62, 95% confidence interval: 0.49-0.78), with low level of heterogeneity (I²=22.6%, P=0.228). Nine studies with 2248 patients reported the adverse cardiovascular events. A fixed-effect model was applied. Compared with control group, patients with high-does Atorvastatin taken, the risk of adverse cardiovascular events was degraded by 65% (Relative risk, RR=0.65, 95% confidence interval (CI): 0.50-0.84), which was confirmed by trial sequential analysis as the cumulative Z curve entered the futility area. The subgroup analyses found that decreased risks of myocardial infarction among trails (RR=0.64, 95%CI: 0.50-0.83, RR=0.55, 95%CI: 0.34-0.88). Egger and Begg’s test found no publication bias (t=-1.670, P=0.129; Z=1.560, P=0.119). The use of high-dose Atorvastatin could reduce the risk of myocardial infraction and cardiovascular adverse events in patients with percutaneous coronary intervention. High-dose Atorvastatin was recommended as an adjunct to aid percutaneous coronary intervention.

Effect of metoprolol on myocardial apoptosis after coronary microembolization in rats

BACKGROUND

Coronary microembolization (CME) is a serious complication following percutaneous coronary intervention (PCI) in patients with acute coronary syndromes. The use of metoprolol before PCI can significantly protect ischemic myocardium from myocardial damage, but the function of metoprolol in the treatment of CME is not entirely clear. This study was to explore the effect and significance of metoprolol on myocardial apoptosis and caspase-3 activation after CME in rats.

METHODS

Thirty rats were randomly divided into three groups including sham-operation (control group), CME plus saline (CME group), CME plus metoprolol (metoprolol group), 10 rats for each group. The CME group was induced by injecting 3 000 polyethylene microspheres (42 μm) into the left ventricle during a 10-second occlusion of the ascending aorta; the control group was injected with physiological saline instead of microembolization ball; the metoprolol or saline group was given three intravenous bolus injections before CME. Echocardiography, TUNEL staining, and Western blotting were used to evaluate cardiac function, proportion of apoptotic cells and activation of caspase-3 respectively at 6 hours after operation.

RESULTS

Echocardiographic parameters displayed that the metoprolol group improved cardiac function significantly compared with the CME group (P<0.05). The myocardial apoptotic rate of the CME group as well as the contents of activated caspase-3 increased significantly (P<0.05), both of which were ameliorated significantly by metoprolol treatment (P<0.05).

CONCLUSIONS

This study demonstrates that metoprolol can protect the myocardium during CME in rats by inhibiting apoptosis and improving cardiac function. These results suggest that the inhibition of apoptosis can be a potential therapeutic strategy for the treatment of CME.

Peri-procedural myocardial injury during percutaneous coronary intervention: an important target for cardioprotection

Percutaneous coronary intervention (PCI) has become the predominant procedure for coronary revascularization in patients with both stable and unstable coronary artery disease (CAD). Over the past two decades, technical advances in PCI have resulted in a better and safer therapeutic procedure with minimal procedural complications. However, about 30% of patients undergoing elective PCI sustain myocardial injury arising from the procedure itself, the extent of which is significant enough to carry prognostic importance. The peri-procedural injury which accompanies PCI might therefore reduce some of the beneficial effects of coronary revascularization. The availability of more sensitive serum biomarkers of myocardial injury such as creatine phosphokinase MB isoenzyme (CK-MB), Troponin T, and Troponin I has enabled the quantification of previously undetectable myocardial injury. Peri-procedural myocardial injury (PMI) can also be visualized by cardiac magnetic resonance imaging, a technique which allows the detection and quantification of myocardial necrosis following PCI. The identification of CAD patients at greatest risk of sustaining PMI during PCI would allow targeted treatment with novel therapies capable of limiting the extent of PMI or reducing the number of patients experiencing PMI.