Kinetics Analysis of Circulating MicroRNAs Unveils Markers of Failed Myocardial Reperfusion.

BACKGROUND: Failed myocardial reperfusion occurs in approximately 50% of patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI). It manifests as microvascular obstruction (MVO) on cardiac magnetic resonance (CMR) imaging. Although prognostically important, MVO is not routinely screened for. Our aim was to investigate the kinetics of circulating short noncoding ribonucleic acids [microRNAs (miRNAs)] following PPCI and their association with MVO in STEMI patients. METHODS: Screening of 2083 miRNAs in plasma from STEMI patients with (n = 6) and without (n = 6) MVO was performed by next-generation sequencing. Two candidate miRNAs were selected and quantified at 13 time points within 3 h postreperfusion in 20 STEMI patients by reverse transcription and quantitative PCR. Subsequently, these 2 miRNAs were measured in a "validation" STEMI cohort (n = 50) that had CMR imaging performed at baseline and 3 months post-PPCI to evaluate their association with MVO. RESULTS: miR-1 and miR-133b were rapidly released following PPCI in a monophasic or biphasic pattern. Both miRNAs were enriched in circulating microparticles. A second miR-1 peak (90-180 min postreperfusion) seemed to be associated with a higher index of microvascular resistance. In addition, miR-1 and miR-133b levels at 90 min post-PPCI were approximately 3-fold (P = 0.001) and 4.4-fold (P = 0.008) higher in patients with MVO, respectively. Finally, miR-1 was significantly increased in a subgroup of patients with worse left ventricular (LV) functional recovery 3 months post-PPCI. CONCLUSIONS: miR-1 and miR-133b levels increase within 3 h of PPCI. They are positively associated with MVO and worse LV functional recovery post-PPCI.

Effect of ciclosporin on safety, lymphocyte kinetics and left ventricular remodelling in acute myocardial infarction.

AIMS: Following a favourable pilot trial using a single bolus of ciclosporin, it has been unclear why 2 large studies (CYCLE and CIRCUS) failed to prevent reperfusion injury and reduce infarct size in STEMI (ST elevation myocardial infarction). The purpose of this study was to assess the effect of ciclosporin on myocardial injury, left ventricular remodelling and lymphocyte kinetics in patients with acute STEMI undergoing primary percutaneous coronary intervention. METHODS: In this double-blind, single centre trial, we randomly assigned 52 acute STEMI patients with an onset of pain of <6 hours and blocked culprit artery to a single bolus of ciclosporin (n = 26) or placebo (n = 26, control group) prior to reperfusion by stent percutaneous coronary intervention. The primary endpoint was infarct size at 12 weeks. RESULTS: Mean infarct size at 12 weeks was identical in both groups (9.1% [standard deviation= 7.0] vs 9.1% [standard deviation = 7.0], P = .99; 95% confidence interval for difference: -4.0 to 4.1). CD3 T-lymphocytes dropped to similar levels at 90 minutes (867 vs 852 cells/µL, control vs ciclosporin) and increased to 1454 vs 1650 cells/µL at 24 hours. CONCLUSION: In our pilot trial, a single ciclosporin bolus did not affect infarct size or left ventricular remodelling, matching the results from CYCLE and CIRCUS. Our study suggests that ciclosporin does either not reach ischaemic cardiomyocytes, or requires earlier application during first medical contact. Finally, 1 bolus of ciclosporin is not sufficient to inhibit CD4 T-lymphocyte proliferation during remodelling. We therefore believe that further studies are warranted. (Evaluating the effectiveness of intravenous Ciclosporin on reducing reperfusion injury in pAtients undergoing PRImary percutaneous coronary intervention [CAPRI]; NCT02390674).

Arginine Vasopressin Plays a Role in Microvascular Dysfunction After ST-Elevation Myocardial Infarction.

Background Coronary microvascular dysfunction (CMD) predicts mortality after ST-elevation-myocardial infarction (STEMI). Arginine vasopressin (AVP) may be implicated, but data in humans are lacking, and no study has investigated the link between arginine vasopressin and invasive measures of CMD. Methods and Results We invasively assessed CMD in 55 patients with STEMI treated with primary percutaneous coronary intervention (PPCI), by measuring the index of microcirculatory resistance after PPCI. In a separate group of 45 patients with STEMI/PPCI, recruited for a clinical trial, we measured infarct size and microvascular obstruction with cardiac magnetic resonance (CMR) imaging at 1 week and 12 weeks post-STEMI. Serum copeptin was measured at 4 time points before and after PPCI in all patients with STEMI. Plasma copeptin levels fell from 92.5 pmol/L before reperfusion to 6.4 pmol/L at 24 hours. Copeptin inversely correlated with diastolic, but not systolic, blood pressure (r=-0.431, P=0.001), suggesting it is released in response to myocardial ischemia. Persistently raised copeptin at 24 hours was correlated with higher index of microcirculatory resistance (r=0.372, P=0.011). Patients with microvascular obstruction on early CMR imaging showed a trend toward higher admission copeptin, which was not statistically significant. Copeptin levels were not associated with infarct size on either early or late CMR. Conclusions Patients with CMD after STEMI have persistently elevated copeptin at 24 hours, suggesting arginine vasopressin may contribute to microvascular dysfunction. Arginine vasopressin receptor antagonists may represent a novel therapeutic option in patients with STEMI and CMD.

Role of coronary angiogram before transcatheter aortic valve implantation.

BACKGROUND: Coexistent coronary artery disease is commonly seen in patients undergoing transcatheter aortic valve implantation (TAVI). Previous studies showed that pre-TAVI coronary revascularisation was not associated with improved outcomes, challenging the clinical value of routine coronary angiogram (CA). AIM: To assess whether a selective approach to perform pre-TAVI CA is safe and feasible. METHODS: This was a retrospective non-randomised single-centre analysis of consecutive patients undergoing TAVI. A selective approach for performing CA tailored to patient clinical need was developed. Clinical outcomes were compared based on whether patients underwent CA. The primary endpoint was a composite of all-cause mortality, myocardial infraction, repeat CA, and re-admission with heart failure. RESULTS: Of 348 patients (average age 81 ± 7 and 57% male) were included with a median follow up of 19 (9-31) mo. One hundred and fifty-four (44%) patients, underwent CA before TAVI procedure. Patients who underwent CA were more likely to have previous myocardial infarction (MI) and previous percutaneous revascularisation. The primary endpoint was comparable between the two group (22.6% vs 22.2%; hazard ratio 1.05, 95%CI: 0.67-1.64, P = 0.82). Patients who had CA were less likely to be readmitted with heart failure (P = 0.022), but more likely to have repeat CA (P = 0.002) and MI (P = 0.007). In those who underwent CA, the presence of flow limiting lesions did not affect the incidence of primary endpoint, or its components, except for increased rate of repeat CA. CONCLUSION: Selective CA is a feasible and safe approach. The clinical value of routine CA should be challenged in future randomised trials.

The Fractalkine Receptor CX3CR1 Links Lymphocyte Kinetics in CMV-Seropositive Patients and Acute Myocardial Infarction With Adverse Left Ventricular Remodeling.

Aims: Latent cytomegalovirus (CMV) infection is associated with adverse cardiovascular outcomes. Virus-specific CX3CR1+ effector memory T-cells may be instrumental in this process due to their pro-inflammatory properties. We investigated the role of CX3CR1 (fractalkine receptor) in CMV-related lymphocyte kinetics and cardiac remodeling in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI). Methods and Results: We retrospectively analysed lymphocyte count, troponin, and survival in 4874 STEMI/pPCI patients, evaluated lymphocyte kinetics during reperfusion in a prospective cohort, and obtained sequential cardiac MRI (cMRI) to assess remodeling. Pre-reperfusion lymphopenia independently predicted mortality at 7.5 years. Prior to reperfusion, CCR7+ T-lymphocytes appeared to be depleted. After reperfusion, T-lymphocytes expressing CX3CR1 were depleted predominantly in CMV-seropositive patients. During ischaemia/reperfusion, a drop in CX3CR1+ T-lymphocytes was significantly linked with microvascular obstruction in CMV+ patients, suggesting increased fractalkine-receptor interaction. At 12 weeks, CMV+ patients displayed adverse LV remodeling. Conclusion: We show that lymphopenia occurs before and after reperfusion in STEMI by different mechanisms and predicts long-term outcome. In CMV+ patients, increased fractalkine induction and sequestration of CX3CR1+ T-cells may contribute to adverse remodeling, suggesting a pro-inflammatory pathomechanism which presents a novel therapeutic target.

Overcoming Heparin-Associated RT-qPCR Inhibition and Normalization Issues for microRNA Quantification in Patients with Acute Myocardial Infarction.

BACKGROUND: Cardiac-enriched micro ribonucleic acids (miRNAs) are released into the circulation following ST-elevation myocardial infarction (STEMI). Lack of standardized approaches for reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) data normalization and presence of RT-qPCR inhibitors (e.g. heparin) in patient blood samples have prevented reproducible miRNA quantification in this cohort and subsequent translation of these biomarkers to clinical practice. MATERIALS AND METHODS: Using a RT-qPCR miRNA screening platform, we identified and validated an endogenous circulating miRNA as a normalization control. In addition, we assessed the effects of in vivo and in vitro anticoagulant drugs administration (heparin and bivalirudin) on three RT-qPCR normalization strategies (global miRNA mean, exogenous spike-in control [cel-miR-39] and endogenous miRNA control). Finally, we evaluated the effect of heparin and its in vitro inhibition with heparinase on the quantification of cardiac-enriched miRNAs in STEMI patients. RESULTS: miR-425-5p was validated as an endogenous miRNA control. Heparin administration in vitro and in vivo inhibited all RT-qPCR normalization strategies. In contrast, bivalirudin had no effects on cel-miR-39 or miR-425-5p quantification. In vitro RNA sample treatment with 0.3 U of heparinase overcame heparin-induced over-estimation of cardiac-enriched miRNA levels and improved their correlation with high-sensitivity troponin T. CONCLUSION: miRNA quantification in STEMI patients receiving heparin is jeopardized by its effect on all RT-qPCR normalization approaches. Use of samples from bivalirudin-treated patients or in vitro treatment of heparin-contaminated samples with heparinase are suitable alternatives for miRNA quantification in this cohort. Finally, we reinforce the evidence that cardiac-enriched miRNAs early after myocardial reperfusion reflect the severity of cardiac injury.

Local Versus General Anesthesia in Transcatheter Aortic Valve Replacement.

Transcatheter aortic valve replacement (TAVR) is conventionally performed under general anesthesia (GA) allowing intraoperative transoesophageal echocardiogram imaging. We present our experience in patients having the procedure under local anesthesia (LA), who were subsequently transferred to a low dependency unit postprocedure, to assess safety and length of hospital stay. We retrospectively assessed all the transfemoral TAVR procedures conducted at our center from January 03, 2011. Of 216 patients, 145 had the procedure under GA and 71 under LA. Both groups were similar with respect to age, co-morbidities, Euro Score, and the severity of the aortic stenosis. The procedure time was significantly shorter in the LA group measured from time in room to skin closure (108 vs 143 minutes, p <0.001). Skin open to skin closure time were the same in both groups (78 vs 79.4 minutes, p = 0.57). There was no difference in 30 days: aortic regurgitation > mild (2.1% in GA and 2.8% in LA, p = 0.67), need for permanent pacing (3.4% in GA and 1.4% in LA, p = 0.32), and disabling cerebrovascular accidents (1.4% and 1.4%, p = 1.0). The 30-day survival was not significantly different (95.9% in GA and 100% in LA, p = 0.17), whereas the median number of days in hospital was shorter in the LA group (4 in GA and 2 in LA, p <0.001). No emergency conversions to GA were performed in the LA group and only 1 patient needed admission to a high dependency (HD) unit. In conclusion, performing a TAVR under LA is at least as safe as GA. In addition, there is a reduced procedural time and length of hospital stay. LA is a safe and cost-effective alternative to GA and patients can be safely transferred to a low dependency unit.