Mika Laine

Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI

Background Coronary revascularization guided by fractional flow reserve (FFR) is associated with better patient outcomes after the procedure than revascularization guided by angiography alone. It is unknown whether the instantaneous wave‐free ratio (iFR), an alternative measure that does not require the administration of adenosine, will offer benefits similar to those of FFR. Methods We randomly assigned 2492 patients with coronary artery disease, in a 1:1 ratio, to undergo either iFR‐guided or FFR‐guided coronary revascularization. The primary end point was the 1‐year risk of major adverse cardiac events, which were a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization. The trial was designed to show the noninferiority of iFR to FFR, with a margin of 3.4 percentage points for the difference in risk. Results At 1 year, the primary end point had occurred in 78 of 1148 patients (6.8%) in the iFR group and in 83 of 1182 patients (7.0%) in the FFR group (difference in risk, ‐0.2 percentage points; 95% confidence interval [CI], ‐2.3 to 1.8; P<0.001 for noninferiority; hazard ratio, 0.95; 95% CI, 0.68 to 1.33; P=0.78). The risk of each component of the primary end point and of death from cardiovascular or noncardiovascular causes did not differ significantly between the groups. The number of patients who had adverse procedural symptoms and clinical signs was significantly lower in the iFR group than in the FFR group (39 patients [3.1%] vs. 385 patients [30.8%], P<0.001), and the median procedural time was significantly shorter (40.5 minutes vs. 45.0 minutes, P=0.001). Conclusions Coronary revascularization guided by iFR was noninferior to revascularization guided by FFR with respect to the risk of major adverse cardiac events at 1 year. The rate of adverse procedural signs and symptoms was lower and the procedural time was shorter with iFR than with FFR. (Funded by Philips Volcano; DEFINE‐FLAIR ClinicalTrials.gov number, NCT02053038.)

A prospective, randomized trial of intravascular-ultrasound guided compared to angiography guided stent implantation in complex coronary lesions: The AVIO trial

BACKGROUND No randomized studies have thus far evaluated intravascular ultrasound (IVUS) guidance in the drug-eluting stent (DES) era. The aim was to evaluate if IVUS optimized DES implantation was superior to angiographic guidance alone in complex lesions. METHODS Randomized, multicentre, international, open label, investigator-driven study evaluating IVUS vs angiographically guided DES implantation in patients with complex lesions (defined as bifurcations, long lesions, chronic total occlusions or small vessels). Primary study endpoint was post-procedure in lesion minimal lumen diameter. Secondary end points were combined major adverse cardiac events (MACE), target lesion revascularization, target vessel revascularization, myocardial infarction (MI), and stent thrombosis at 1, 6, 9, 12, and 24 months. RESULTS The study included 284 patients. No significant differences were observed in baseline characteristics. The primary study end point showed a statistically significant difference in favor of the IVUS group (2.70 mm ± 0.46 mm vs. 2.51 ± 0.46 mm; P = .0002). During hospitalization, no patient died, had repeated revascularization, or a Q-wave MI. No difference was observed in the occurrence of non-Q wave MI (6.3% in IVUS vs. 7.0% in angio-guided group). At 24-months clinical follow-up, no differences were still observed in cumulative MACE (16.9%vs. 23.2 %), cardiac death (0%vs. 1.4%), MI (7.0%vs. 8.5%), target lesion revascularization (9.2% vs. 11.9%) or target vessel revascularization (9.8% vs. 15.5%), respectively in the IVUS vs. angio-guided groups. In total, only one definite subacute stent thrombosis occurred in the IVUS group. CONCLUSIONS A benefit of IVUS optimized DES implantation was observed in complex lesions in the post-procedure minimal lumen diameter. No statistically significant difference was found in MACE up to 24 months.

Levosimendan Facilitates Weaning From Cardiopulmonary Bypass in Patients Undergoing Coronary Artery Bypass Grafting With Impaired Left Ventricular Function

BACKGROUND Levosimendan is a compound with vasodilatory and inotropic properties. Experimental data suggest effective reversal of stunning and cardioprotective properties. METHODS This prospective, randomized, placebo-controlled, double-blind study included 60 patients with 3-vessel coronary disease and left ventricular ejection fraction (LVEF) of less than 0.50. Levosimendan administration (12 microg/kg bolus, followed by an infusion of 0.2 microg/kg/min) was started immediately after induction anesthesia. Predefined strict hemodynamic criteria were used to assess the success of weaning. If weaning was not successful, CPB was reinstituted and an epinephrine infusion was started. If the second weaning attempt failed, intraaortic balloon pumping (IABP) was instituted. RESULTS The groups had comparable demographics. The mean (standard deviation) preoperative LVEF was 0.36 (0.8) in both groups. The baseline cardiac index was 1.8 (0.3) L/min/m(2) in the levosimendan group and 1.9 (0.4) L/min/m(2) in the placebo group. The mean duration of CPB to primary weaning attempt was 104 (25) minutes in the levosimendan and 109 (22) minutes in the placebo group. Primary weaning was successful in 22 patients (73%) in the levosimendan group and in 10 (33%) in the placebo group (p = 0.002). The odds ratio for failure in primary weaning was 0.182 (95% confidence interval, 0.060 to 0.552). Four patients in the placebo group failed the second weaning and underwent IABP compared with none in the levosimendan group (p = 0.112). CONCLUSIONS Levosimendan significantly enhanced primary weaning from CPB compared with placebo in patients undergoing 3-vessel on-pump coronary artery bypass grafting. The need for additional inotropic or mechanical therapy was decreased.

Duration of the haemodynamic action of a 24-h infusion of levosimendan in patients with congestive heart failure

To determine the duration of haemodynamic and neurohormonal action of a 24‐h infusion of levosimendan in heart failure.

Cell Model of Catecholaminergic Polymorphic Ventricular Tachycardia Reveals Early and Delayed Afterdepolarizations

Background Induced pluripotent stem cells (iPSC) provide means to study the pathophysiology of genetic disorders. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a malignant inherited ion channel disorder predominantly caused by mutations in the cardiac ryanodine receptor (RyR2). In this study the cellular characteristics of CPVT are investigated and whether the electrophysiological features of this mutation can be mimicked using iPSC -derived cardiomyocytes (CM). Methodology/Principal Findings Spontaneously beating CMs were differentiated from iPSCs derived from a CPVT patient carrying a P2328S mutation in RyR2 and from two healthy controls. Calcium (Ca2+) cycling and electrophysiological properties were studied by Ca2+ imaging and patch-clamp techniques. Monophasic action potential (MAP) recordings and 24h-ECGs of CPVT-P2328S patients were analyzed for the presence of afterdepolarizations. We found defects in Ca2+ cycling and electrophysiology in CPVT CMs, reflecting the cardiac phenotype observed in the patients. Catecholaminergic stress led to abnormal Ca2+ signaling and induced arrhythmias in CPVT CMs. CPVT CMs also displayed reduced sarcoplasmic reticulum (SR) Ca2+ content, indicating leakage of Ca2+ from the SR. Patch-clamp recordings of CPVT CMs revealed both delayed afterdepolarizations (DADs) during spontaneous beating and in response to adrenaline and also early afterdepolarizations (EADs) during spontaneous beating, recapitulating the changes seen in MAP and 24h-ECG recordings of patients carrying the same mutation. Conclusions/Significance This cell model shows aberrant Ca2+ cycling characteristic of CPVT and in addition to DADs it displays EADs. This cell model for CPVT provides a platform to study basic pathology, to screen drugs, and to optimize drug therapy.

Downregulation of the HERG (KCNH2) K(+) channel by ceramide: evidence for ubiquitin-mediated lysosomal degradation.

The HERG (KCNH2) potassium channel underlies the rapid component of the delayed rectifier current (Ikr), a current contributing to the repolarisation of the cardiac action potential. Mutations in HERG can cause the hereditary forms of the short-QT and long-QT syndromes, predisposing to ventricular arrhythmias and sudden cardiac death. HERG is expressed mainly in the cell membrane of cardiac myocytes, but has also been identified in cell membranes of a range of other cells, including smooth muscle and neurones. The mechanisms regulating the surface expression have however not yet been elucidated. Here we show, using stable HERG-expressing HEK 293 cells, that ceramide evokes a time-dependent decrease in HERG current which was not attributable to a change in gating properties of the channel. Surface expression of the HERG channel protein was reduced by ceramide as shown by biotinylation of surface proteins, western blotting and immunocytochemistry. The rapid decline in HERG protein after ceramide stimulation was due to protein ubiquitylation and its association with lysosomes. The results demonstrate that the surface expression of HERG is strictly regulated, and that ceramide modifies HERG currents and targets the protein for lysosomal degradation.

Cardiac mechanotransduction: from sensing to disease and treatment

In heart muscle a mechanical stimulus is sensed and transformed into adaptive changes in cardiac function by a process called mechanotransduction. Adaptation of heart muscle to mechanical load consists of neurohumoral activation and growth, both of which decrease the initial load. Under prolonged overload this process becomes maladaptive, leading to the development of left ventricular hypertrophy and ultimately to heart failure. Widespread synergism and crosstalk among a variety of molecules and signals involved in hypertrophic signaling pathways make the prevention or treatment of left ventricular hypertrophy and heart failure a challenging task. Therapeutic strategies should include either a complete and continuous reduction of load or normalization of left ventricular mass by interventions aimed at specific targets involved in mechanotransduction.

Heme oxygenase-1 and carbon monoxide promote neovascularization after myocardial infarction by modulating the expression of HIF-1α, SDF-1α and VEGF-B

Heme oxygenase-1 (HO-1), a known cytoprotective enzyme implicated also in the cell cycle regulation and angiogenesis, exerts many of its beneficial effects through carbon monoxide (CO). We studied the roles of HO-1 and CO in cardiac regeneration after myocardial infarction. Prior to coronary artery ligation, male Wistar rats were given either cobolt protoporphyrin IX to induce HO-1 or CO-donor methylene chloride. Cardiac regeneration was assessed by immunohistochemistry and confocal microscopy. CO significantly increased the accumulation of c-kit+ stem/progenitor cells into the infarct area and induced formation of new coronary arteries by promoting a substantial differentiation of c-kit+ cells into vascular smooth muscle cells (c-kit+/GATA6+ cells). Furthermore, CO increased proliferation of cardiomyocytes in the infarct border area at 4weeks post-infarction. This suggests proliferation of newly formed cardiomyocytes derived from c-kit+ cells as 10% of c-kit+ cells expressed early cardiac marker Nkx2.5. Increased expression of hypoxia-inducible factor-1alpha (HIF-1alpha), stromal cell derived factor-1alpha (SDF-1alpha) and vascular endothelial growth factor-B (VEGF-B) were found in the infarct areas of CO-donor pretreated hearts suggesting that these factors potentially promoted the migration of c-kit+ cells into the infarct area and subsequent vasculogenesis and myocardial regeneration by CO. HO-1 increased both capillary and vascular densities, while only a small increase of c-kit+ cells was found. HO-1 upregulated SDF-1alpha, but did not have effect on HIF-1alpha and VEGF-B. In conclusion, HO-1 and CO have differential roles and mechanisms of action in cardiac regeneration. Modulation of the HO-1/CO axis may provide a novel tool for the repair of cardiac injury.

One‐Year Outcome of Patients With Atrial Fibrillation Undergoing Coronary Artery Stenting: An Analysis of the AFCAS Registry

Most evidence regarding the efficacy and safety of the antithrombotic regimens for patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention with stent (PCI‐S) derives from small, single‐center, retrospective datasets. To obtain further data on this issue, we carried out the prospective, multicenter, observational Management of patients with Atrial Fibrillation undergoing Coronary Artery Stenting (AFCAS) registry (Clinicaltrials.gov identifier NCT00596570).

Inhibition of delta-protein kinase C by delcasertib as an adjunct to primary percutaneous coronary intervention for acute anterior ST-segment elevation myocardial infarction: results of the PROTECTION AMI Randomized Controlled Trial

AIMS Delcasertib is a selective inhibitor of delta-protein kinase C (delta-PKC), which reduced infarct size during ischaemia/reperfusion in animal models and diminished myocardial necrosis and improved reperfusion in a pilot study during primary percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI). METHODS AND RESULTS A multicentre, double-blind trial was performed in patients presenting within 6 h and undergoing primary PCI for anterior (the primary analysis cohort, n = 1010 patients) or inferior (an exploratory cohort, capped at 166 patients) STEMI. Patients with anterior STEMI were randomized to placebo or one of three doses of delcasertib (50, 150, or 450 mg/h) by intravenous infusion initiated before PCI and continued for ∼2.5 h. There were no differences between treatment groups in the primary efficacy endpoint of infarct size measured by creatine kinase MB fraction area under the curve (AUC) (median 5156, 5043, 4419, and 5253 ng h/mL in the placebo, delcasertib 50, 150, and 450 mg/mL groups, respectively) in the anterior STEMI cohort. No treatment-related differences were seen in secondary endpoints of infarct size, electrocardiographic ST-segment recovery AUC or time to stable ST recovery, or left ventricular ejection fraction at 3 months. No differences in rates of adjudicated clinical endpoints (death, heart failure, or serious ventricular arrhythmias) were observed. CONCLUSIONS Selective inhibition of delta-PKC with intravenous infusion of delcasertib during PCI for acute STEMI in a population of patients treated according to contemporary standard of care did not reduce biomarkers of myocardial injury.