Remote Ischemic Conditioning in Elective PCI?

Preconditioning Strategies for Improving the Outcome of Fat Grafting

Autologous fat grafting is a common procedure in plastic, reconstructive, and aesthetic surgery. However, it is frequently associated with an unpredictable resorption rate of the graft depending on the engraftment kinetics. This, in turn, is determined by the interaction of the grafted adipose tissue with the tissue at the recipient site. Accordingly, preconditioning strategies have been developed following the principle of exposing these tissues in the pretransplantation phase to stimuli inducing endogenous protective and regenerative cellular adaptations, such as the upregulation of stress-response genes or the release of cytokines and growth factors. As summarized in the present review, these stimuli include hypoxia, dietary restriction, local mechanical stress, heat, and exposure to fractional carbon dioxide laser. Preclinical studies show that they promote cell viability, adipogenesis, and angiogenesis, while reducing inflammation, fibrosis, and cyst formation, resulting in a higher survival rate and quality of fat grafts in different experimental settings. Hence, preconditioning represents a promising approach to improve the outcome of fat grafting in future clinical practice. For this purpose, it is necessary to establish standardized preconditioning protocols for specific clinical applications that are efficient, safe, and easy to implement into routine procedures.

The Impact of Coexistence of Smoking and Diabetes on the Coronary Artery Severity and Outcomes following Percutaneous Coronary Intervention: Results from the 1ST Jordanian PCI Registry

Introduction

Diabetes mellitus (DM) and smoking are highly prevalent among Middle Eastern patients admitted with acute coronary syndrome (ACS) or who undergo percutaneous coronary intervention (PCI).

Methods

This study used the analysis of the data from the first Jordanian PCI registry (JoPCR1) to determine the impact of coexistence of smoking and diabetes mellitus on the coronary artery severity and outcome following percutaneous coronary intervention in Middle Eastern patients.

Results

Of 2426 patients enrolled, 1300 (53.6%) and 1055 (43.5%) were diabetics and smokers, respectively. The patients' age was 59.0 ± 10.1 and ranged between 24 and 95 years. Males comprised 79.4% of all patients. The patients were divided into four groups: nondiabetic-nonsmokers (22.2%), diabetic-nonsmokers (34.3%), nondiabetic-smokers (24.2%), and diabetic-smokers (19.2%). Compared with the other three groups, patients in the diabetic-nonsmoker group were older, more likely to be females, and having a higher prevalence of hypertension, dyslipidemia, chronic renal disease, and history of CVD and revascularization. Consequently, the diabetic-nonsmoker patients (but not the diabetic-smokers) had a higher prevalence of multivessel CAD and PCI than the other three groups, highlighting the importance of other risk factors (age, gender, metabolic syndrome, and comorbidities) and not only smoking in predisposing for CAD. Furthermore, those patients had a higher incidence of ACS as an indication for PCI than the stable coronary disease (73% vs 27%) and the highest CRUSADE bleeding risk score (63.9%) among other groups. The in-hospital events including in-stent thrombosis and emergency CABG events did not significantly differ among groups (p = 0.5 and 0.22). Heart failure and major bleeding events occurred significantly higher among diabetic-nonsmokers compared to other groups. In-hospital deaths occurred significantly more among diabetic-nonsmokers. Moreover, the one-month and one-year follow-up outcome events (the mortality rate, in-stent thrombosis, readmission for ACS, coronary revascularization, and major bleedings) occurred more frequently in the diabetic-nonsmoker group. However, the difference was statistically significant only for major bleeding incidences.

Conclusions

In this analysis of a completed prospective Middle Eastern PCI registry, the majority of the diabetic-nonsmoker (and not the diabetic-smokers) patients (73%) presented with ACS. This group was the highest at risk for in-hospital PCI complications as well as the worst in outcomes after one year of follow-up. Those patients were more likely to be older, female, and have the worst cardiovascular baseline features, highlighting the importance of other risk factors (age, gender, metabolic syndrome, and comorbidities) and not only smoking in predisposing for CAD. Thus, more sufficient education about controlling CVD risk factors should be implemented in the Middle Eastern region.

The Future of Cardioprotection-Pointing Toward Patients at Elevated Risk as the Target Populations

Translation of the cardioprotective effect by pharmacological and mechanical conditioning therapies into improvement of clinical outcome for the patients has been disappointing. Confounding factors like comorbidity and comedications may explain some of the loss in translation. However, the substantial improvement of outcome in disease states involving ischemia-reperfusion injury, that is, planned cardiac surgery, elective percutaneous coronary intervention, and even primary percutaneous coronary intervention for ST-segment myocardial infarction (STEMI), is the most plausible explanation for the missed demonstration of a clinical benefit. Remote ischemic conditioning has demonstrated consistent cardioprotective effect in experimental and in clinical proof-of-concept studies. As an adjunctive cardioprotective treatment beyond reperfusion, remote ischemic conditioning should address target populations at risk of extensive tissue damage, including patients who experience complications, which may induce profound myocardial ischemia in relation to cardiac surgery or elective percutaneous coronary intervention. Moreover, patients with STEMI and predictable impaired clinical outcome due to delayed hospital admission, high Killip class, cardiogenic shock, and cardiac arrest remain target groups. For high-risk patients, daily remote ischemic conditioning or the corollary of blood flow-restricted exercise may be alternative cardioprotective options during postoperative and post-myocardial infarct rehabilitation.

Procedural microvascular activation in long lesions treated with bioresorbable vascular scaffolds or everolimus-eluting stents: the PROACTIVE trial

AIMS

Significant platelet activation after long stented coronary segments has been associated with periprocedural microvascular impairment and myonecrosis. In long lesions treated either with an everolimus-eluting bioresorbable vascular scaffold (BVS) or an everolimus-eluting stent (EES), we aimed to investigate (a) procedure-related microvascular impairment, and (b) the relationship of platelet activation with microvascular function and related myonecrosis.

METHODS AND RESULTS

Patients (n=66) undergoing elective percutaneous coronary intervention (PCI) in long lesions were randomised 1:1 to either BVS or EES. The primary endpoint was the difference between groups in changes of pressure-derived corrected index of microvascular resistance (cIMR) after PCI. Periprocedural myonecrosis was assessed by high-sensitivity cardiac troponin T (hs-cTnT), platelet reactivity by high-sensitivity adenosine diphosphate (hs-ADP)-induced platelet reactivity with the Multiplate Analyzer. Post-dilatation was more frequent in the BVS group, with consequent longer procedure time. A significant difference was observed between the two groups in the primary endpoint of ΔcIMR (p=0.04). hs-ADP was not different between the groups at different time points. hs-cTnT significantly increased after PCI, without difference between the groups.

CONCLUSIONS

In long lesions, BVS implantation is associated with significant acute reduction in IMR as compared with EES, with no significant interaction with platelet reactivity or periprocedural myonecrosis.

Trigger, Signaling Mechanism and End Effector of Cardioprotective Effect of Remote Postconditioning of Heart

The hypothetical trigger of remote postconditioning (RPost) of the heart is the high-molecular weight hydrophobic peptide(s). Nitric oxide and adenosine serve as intermediaries between the peptide and intracellular structures. The role of the autonomic nervous system in RPost requires further study. In signaling mechanism RPost, kinases are involved: protein kinase C, PI3, Akt, JAK. The hypothetical end effector of RPost is aldehyde dehydrogenase-2, the transcription factors STAT, Nrf2, and also the BKCa channel.

Hemostasis based on a novel 'two-path unifying theory' and classification of hemostatic disorders

: Hemostasis is the most important protective mechanism for human survival following harmful vascular damage caused by internal disease or external injury. Physiological mechanism of hemostasis is partially understood. Hemostasis can be initiated by either intravascular injury or external bodily injury involving two different levels of damage [i.e., limited to the endothelium or combined with extravascular tissue (EVT)]. In intravascular injury, traumatic damage limited to local endothelium typically is of no consequence, but disease-induced endothelial damage associated with systemic endothelial injury seen in sepsis and other critical illnesses could cause generalized 'endotheliopathy'. It triggers no bleeding but promotes serious endothelial molecular response. If intravascular local trauma extends beyond the endothelium and into EVT, it causes intravascular 'bleeding' and initiate 'clotting' via normal hemostasis. In external bodily injury, local traumatic damage always extends to the endothelium and EVT, and triggers 'bleeding' and 'clotting'. Systemic endotheliopathy activates only unusually large von Willebrand factor multimers (ULVWF) path and mediates 'microthrombogenesis', producing 'microthrombi' strings. This partial activation of hemostasis with ULVWF path leads to vascular microthrombotic disease. But localized traumatic injury extending to the endothelium and EVT activates both ULVWF and tissue factor paths. Combined activation of ULVWF and tissue factor paths provides normal hemostasis in external bodily injury, but causes 'macrothrombus' formation in intravascular injury. This 'two-path unifying theory' concept succinctly elucidates simplified nature of hemostasis in intravascular and external bodily injuries. It also clarifies different pathogenesis of every hemorrhagic disease and thrombotic disorder related to internal vascular disease and external vascular injury.

Effects of mitochondrial ATP-sensitive potassium channel activation (nicorandil) in patients with angina pectoris undergoing elective percutaneous coronary interventions: A meta-analysis of randomized controlled trials

AIMS

Nicorandil, which is a mitochondrial ATP-sensitive potassium channel opener, is believed to improve perioperative myocardial injury (PMI) in patients undergoing percutaneous coronary intervention (PCI), but recent studies have shown that nicorandil treatment did not improve functional and clinical outcomes in patients with angina pectoris who underwent elective PCI. We performed a meta-analysis to investigate the protective effect of nicorandil on perioperative injury in patients with angina pectoris who underwent elective PCI.

METHODS

The Medline, EMBASE, and Cochrane databases were searched for randomized clinical trials examining the effects of nicorandil. Two investigators independently selected suitable trials, extracted data, and assessed trial quality.

RESULTS

Seven studies of patients undergoing elective PCI, comprising a total of 979 patients, were included in this review. The results showed that nicorandil did not reduce the levels of markers of myocardial injury (standardized mean difference [SMD] 0.31 [95%CI -0.6, 1.22] for creatine kinase-MB [CK-MB] and 1.29 [95%CI -2.18, 4.76] for troponin I [TNI]), perioperative complications (relative risk [RR] 0.91 [95%CI 0.46-1.81]), target vessel revascularization (RR 0.79 [95%CI 0.50-1.25]) or major adverse cardiac events (MACE) (RR 0.83 [95%CI 0.49-1.43]). Nicorandil did reduce the corrected TIMI frame count (SMD-0.30 [95%CI -0.52, -0.09]).

CONCLUSION

Although nicorandil did not reduce the overall incidence of perioperative complications and the incidence of major adverse cardiac events (MACE) in patients with angina pectoris who underwent elective PCI, it could still improve no reflow and slow coronary flow.

Remote ischemic preconditioning fails to reduce infarct size in the Zucker fatty rat model of type-2 diabetes: role of defective humoral communication

Remote ischemic preconditioning (RIPC), the phenomenon whereby brief ischemic episodes in distant tissues or organs render the heart resistant to infarction, has been exhaustively demonstrated in preclinical models. Moreover, emerging evidence suggests that exosomes play a requisite role in conveying the cardioprotective signal from remote tissue to the myocardium. However, in cohorts displaying clinically common comorbidities-in particular, type-2 diabetes-the infarct-sparing effect of RIPC may be confounded for as-yet unknown reasons. To investigate this issue, we used an integrated in vivo and in vitro approach to establish whether: (1) the efficacy of RIPC is maintained in the Zucker fatty rat model of type-2 diabetes, (2) the humoral transfer of cardioprotective triggers initiated by RIPC are transported via exosomes, and (3) diabetes is associated with alterations in exosome-mediated communication. We report that a standard RIPC stimulus (four 5-min episodes of hindlimb ischemia) reduced infarct size in normoglycemic Zucker lean rats, but failed to confer protection in diabetic Zucker fatty animals. Moreover, we provide novel evidence, via transfer of serum and serum fractions obtained following RIPC and applied to HL-1 cardiomyocytes subjected to hypoxia-reoxygenation, that diabetes was accompanied by impaired humoral communication of cardioprotective signals. Specifically, our data revealed that serum and exosome-rich serum fractions collected from normoglycemic rats attenuated hypoxia-reoxygenation-induced HL-1 cell death, while, in contrast, exosome-rich samples from Zucker fatty rats did not evoke protection in the HL-1 cell model. Finally, and unexpectedly, we found that exosome-depleted serum from Zucker fatty rats was cytotoxic and exacerbated hypoxia-reoxygenation-induced cardiomyocyte death.