Ischemic postconditioning during primary percutaneous coronary intervention

Mitigating the risk of flow deterioration by deferring stent optimization in STEMI patients with large thrombus burden: Insights from a prospective cohort study

OBJECTIVES

It is uncertain, if omitting post-dilatation and stent oversizing (stent optimization) is safe and may decrease the risk for distal thrombus embolization (DTE) in STEMI patients with large thrombus burden (LTB).

BACKGROUND

In patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) with stenting, (DTE) and flow deterioration are common and increase infarct size leading to worse outcomes.

METHODS

From a prospective registry, 74 consecutive STEMI patients with LTB undergoing pPCI with stenting and intentionally deferred stent optimization were analyzed. Imaging data and outcomes up to 2 years follow-up were analyzed.

RESULTS

Overall, 74 patients (18% females) underwent deferred stent optimization. Direct stenting was performed in 13 (18%) patients. No major complications occurred during pPCI. Staged stent optimization was performed after a median of 4 (interquartile range (IQR) 3; 7) days. On optical coherence tomography, under-expansion and residual thrombus were present in 59 (80%) and 27 (36%) cases, respectively. During deferred stent optimization, we encountered no case of flow deterioration (slow or no-reflow) or side branch occlusion. Minimal lumen area (mm2) and stent expansion (%) were corrected from 4.87±1.86mm to 6.82±2.36mm (p<0.05) and from 69±18% to 91±12% (p<0.001), respectively. During follow-up, 1 patient (1.4%) required target lesion revascularization and 1 (1.4%) patient succumbed from cardiovascular death.

CONCLUSIONS

Among STEMI patients with LTB, deferring stent optimization in the setting of pPCI appears safe and potentially mitigates the risk of DTE. The impact of this approach on infarct size and clinical outcomes warrants further investigation in a dedicated trial.

Dynamic Regulation of Cysteine Oxidation and Phosphorylation in Myocardial Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion (I/R) injury significantly alters heart function following infarct and increases the risk of heart failure. Many studies have sought to preserve irreplaceable myocardium, termed cardioprotection, but few, if any, treatments have yielded a substantial reduction in clinical I/R injury. More research is needed to fully understand the molecular pathways that govern cardioprotection. Redox mechanisms, specifically cysteine oxidations, are acute and key regulators of molecular signaling cascades mediated by kinases. Here, we review the role of reactive oxygen species in modifying cysteine residues and how these modifications affect kinase function to impact cardioprotection. This exciting area of research may provide novel insight into mechanisms and likely lead to new treatments for I/R injury.

Long-term outcomes of ischemic post-conditioning primary PCI and conventional primary PCI in acute STEMI: a meta-analysis of randomized trials

BACKGROUND

Data regarding ischemic postconditioning during percutaneous coronary intervention (PCI) as compared conventional PCI alone has yielded conflicting results.

METHODS

Online databases comparing use of ischemic postconditioning percutaneous coronary intervention (ICP-PPCI) in STEMI patients with conventional PPCI were selected. Mortality, heart failure (HF), myocardial infarction (MI), and major adverse cardiac events (MACE) were evaluated. The primary outcome was composite of HF, MI, and mortality. Pooled risk ratio (RR) with 95% confidence interval (CI) were computed using random-effects model.

RESULTS

Eight studies consisting of 2,566 patients (ICP-PPCI n = 1,228; PPCI n = 1,278) were included. The mean age for PPCI group was 61.38 ± 7.86 years (51% men) and for PCI 59.83 ± 8.94 years (47% men). There were no differences in outcome between ICP-PPCI and PPCI in terms of HF (RR 0.87 95% CI0.51-1.48; p = 0.29), MI (RR 1.28, 95%CI0.74-2.20; p = 0.20), mortality (RR 0.93, 95%CI0.64-1.34; p = 0.58), and MACE (RR 0.89, 95%CI0.74-1.07; p = 0.22). The results for composite event for the ICP-PPCI and PPIC procedures, at ≥1 year follow-up duration, were comparable (RR 1.00 95%CI0.82-1.22; p = 1).

CONCLUSION

Ischemic postconditioning post percutaneous coronary intervention in STEMI patients has no long-term benefits over conventional PCI.

Effects of Hydrogen-rich Water on the PI3K/AKT Signaling Pathway in Rats with Myocardial Ischemia-reperfusion Injury

BACKGROUND

The effects of hydrogen-rich water on PI3K/AKT-mediated apoptosis were studied in rats subjected to myocardial ischemia-reperfusion injury (MIRI). Methdos: Sixty rats were divided randomly into a hydrogen-rich water group and a control group. The hearts were removed and fixed in a Langendorff device. Hearts from the control group were perfused with K-R solution, and hearts from the hydrogen-rich water group was perfused with K-R solution + hydrogen-rich water. The two treatment groups were then divided randomly into pre-ischemic period, ischemic period and reperfusion period groups(10 rats per group), which were subjected to reverse perfusion for 10 min, normal treatment for 20 min, and reperfusion for 20 min, respectively. The mRNA and protein expression levels of PI3K, AKT, p-AKT, FoxO1, Bim and Caspase-3 in each group were detected by RT-qPCR, immunohistochemistry (IHC) and Western blotting. Caspase-3 activity was detected by spectrophotometry.

RESULTS

Among the hydrogen-rich water group, the PI3K/AKT signaling pathway was significantly activated, and FoxO1, Bim, and Caspase-3 mRNA and protein levels were significantly decreased in ischemia-reperfusion subgroup compared with the preischemic and ischemic subgroups. In the ischemia-reperfusion hydrogen-rich water group, PI3K, AKT and p-AKT mRNA and protein expression levels were increased while the FoxO1, Bim and Caspase-3 expression levels were significantly decreased compared with those in the corresponding control group (P<0.05).

CONCLUSION

Hydrogen-rich water can activate the PI3K/AKT signaling pathway, alleviate ischemia-reperfusion injury in isolated rat hearts, and inhibit cardiomyocyte apoptosis.

Ischemia-reperfusion injury and ischemic post-conditioning in acute myocardial infarction: Lost in translation

Ischemic post-conditioning (IPoC) has been proposed as a strategy to mitigate the risk of ischemia-reperfusion injury during primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). In this comprehensive and updated meta-analysis of randomized controlled trials, IPoC during primary PCI for STEMI had no significant effect on all-cause mortality, re-infarction, or new-onset heart failure compared with no post-conditioning. Further strategies need to be prospectively evaluated to improve outcomes in patients with STEMI undergoing primary PCI.

New and revisited approaches to preserving the reperfused myocardium

Early coronary artery reperfusion improves outcomes for patients with ST-segment elevation myocardial infarction (STEMI), but morbidity and mortality after STEMI remain unacceptably high. The primary deficits seen in these patients include inadequate pump function, owing to rapid infarction of muscle in the first few hours of treatment, and adverse remodelling of the heart in the months that follow. Given that attempts to further reduce myocardial infarct size beyond early reperfusion in clinical trials have so far been disappointing, effective therapies are still needed to protect the reperfused myocardium. In this Review, we discuss several approaches to preserving the reperfused heart, such as therapies that target the mechanisms involved in mitochondrial bioenergetics, pyroptosis, and autophagy, as well as treatments that harness the cardioprotective properties of inhaled anaesthetic agents. We also discuss potential therapies focused on correcting the no-reflow phenomenon and its effect on healing and adverse left ventricular remodelling.

Deferred or immediate stent implantation for primary percutaneous coronary intervention: A meta-analysis of randomized trials

OBJECTIVES

To perform a meta-analysis of randomized trials comparing a deferred versus immediate stenting strategy for primary percutaneous coronary intervention (PCI).

BACKGROUND

Deferred stent implantation has emerged as a potential strategy aiming to reduce the thrombus burden and improve micro-vascular reperfusion during primary PCI.

METHODS

Electronic databases were searched for randomized trials that compared a deferred stent implantation versus immediate stent implantation strategy in patients undergoing primary PCI. Random effects risk ratios (RR) were estimated for the outcomes of interest.

RESULTS

Four trials with 1,570 patients were included. A deferred stent implantation strategy was associated with a lower incidence of no-/slow reflow (RR 0.49, 95% confidence interval [CI] 0.24-0.96), and improved myocardial blush grade 3 (RR 1.42, 95% CI 1.14-1.77). At a mean follow up of 34 ± 15 months, both strategies were associated with a similar risk of all-cause mortality (RR 0.85, 95% CI 0.58-1.24), cardiovascular mortality (RR 0.84, 95% CI 0.48-1.45), reinfarction (RR 1.54, 95% CI 0.43-5.49), and stent thrombosis (RR = 0.35, 95% CI 0.04-3.35, P = 0.36).

CONCLUSION

In patients undergoing primary PCI, deferred stent implantation is associated with improvement in surrogate outcomes, but does not appear to improve clinical outcomes. Future randomized trials are encouraged to identify the patient population who might benefit from a deferred stent implantation strategy (e.g., high thrombus burden).