Mesenchymal stromal cells for improvement of cardiac function following acute myocardial infarction: a matter of timing.

Acute myocardial infarction (AMI) is the leading cause of cardiovascular death and remains the most common cause of heart failure. Reopening of the occluded artery, i.e., reperfusion, is the only way to save the myocardium. However, the expected benefits of reducing infarct size are disappointing due to the reperfusion paradox, which also induces specific cell death. These ischemia-reperfusion (I/R) lesions can account for up to 50% of final infarct size, a major determinant for both mortality and the risk of heart failure (morbidity). In this review, we provide a detailed description of the cell death and inflammation mechanisms as features of I/R injury and cardioprotective strategies such as ischemic postconditioning as well as their underlying mechanisms. Due to their biological properties, the use of mesenchymal stromal/stem cells (MSCs) has been considered a potential therapeutic approach in AMI. Despite promising results and evidence of safety in preclinical studies using MSCs, the effects reported in clinical trials are not conclusive and even inconsistent. These discrepancies were attributed to many parameters such as donor age, in vitro culture, and storage time as well as injection time window after AMI, which alter MSC therapeutic properties. In the context of AMI, future directions will be to generate MSCs with enhanced properties to limit cell death in myocardial tissue and thereby reduce infarct size and improve the healing phase to increase postinfarct myocardial performance.

Long-term follow-up of balloon-expandable valves according to the implantation strategy: insight from the DIRECTAVI trial.

BACKGROUND: Safety and feasibility of transcatheter aortic valve replacement (TAVR) without balloon aortic valvuloplasty (BAV) using the SAPIEN 3 balloon-expandable device has been previously demonstrated. The impact on long-term valve hemodynamic performances and outcomes remains however unknown. We evaluate long-term clinical and hemodynamic results according to the implant strategy (direct TAVR vs BAV pre-TAVR) in patients included in the DIRECTAVI randomized trial (NCT02729519). METHODS: Clinical and echocardiographic follow-up until January 2023 was performed for all patients included in the DIRECTAVI trial since 2016 (n = 228). The primary endpoint was incidence of moderate/severe hemodynamic valve deterioration (HVD), according to the Valve Academic Research defined Consortium-3 criteria (increase in mean gradient ≥10 mmHg resulting in a final mean gradient ≥20 mmHg, or new/worsening aortic regurgitation of 1 grade resulting in ≥ moderate aortic regurgitation). RESULTS: Median follow-up was 3.8 (2.2-4.7) years. Mean age at follow-up was 87 ± 6.7 years. No difference in incidence of HVD in the direct implantation group compared to the BAV group was found (incidence of 1.97 per 100 person-years and 1.45 per 100 person-years, respectively, P = 0.6). Prevalence of predicted prothesis-patient mismatch was low (n = 13 [11.4%] in the direct TAVR group vs n = 15 [13.2%] in BAV group) and similar between both groups (P = .7). Major outcomes including death, stroke, hospitalization for heart failure and pacemaker implantation were similar between both groups, (P = .4, P = .7, P = .3, and P = .3 respectively). CONCLUSION: Direct implantation of the balloon-expandable device in TAVR was not associated with an increased risk of moderate/severe HVD or major outcomes up to 6-year follow-up. These results guarantee wide use of direct balloon-expandable valve implantation, when feasible. CLINICAL TRIALS REGISTRATION NUMBER: NCT05140317.

In-Hospital and 1-Year Clinical Results from the French Registry Using Polymer-Free Sirolimus-Eluting Stents in Acute Coronary Syndrome and Stable Coronary Artery Disease.

Objectives: The aim of this postmarket clinical study was to assess the safety and efficacy of the latest generation polymer-free sirolimus-eluting stents (PF-SES) in an all-comers population comparing outcomes in stable coronary artery disease (CAD) versus acute coronary syndrome (ACS) in France. Background: The efficacy and safety of the first-generation PF-SES have already been demonstrated by randomized controlled trials and "all-comers" observational studies. Methods: For this all-comers observational, prospective, multicenter study, 1456 patients were recruited in 22 French centers. The primary endpoint was target lesion revascularization (TLR) rate at 12 months and secondary endpoints included major adverse cardiac events (MACE) and bleeding. Results: 895 patients had stable CAD and 561 had ACS. At 12 months, 2% of patients had a TLR, with similar rates between stable CAD and ACS (1.9% vs 2.2%, p = 0.7). The overall MACE rate was 5.2% with an expected higher rate in patients with ACS as compared to those with stable CAD (7.3% vs 3.9%, p = 0.007). The overall bleeding event rate was 4.5%, with similar rates in stable CAD as compared to ACS patients (3.8% vs 5.6%, p = 0.3). Dual antiplatelet therapy (DAPT) interruptions prior to the recommended duration occurred in 41.7% of patients with no increase in MACE rates as compared to patients who did not prematurely interrupt DAPT (3.9% vs 6.1%, p = 0.073). Conclusions: The latest generation PF-SES is associated with low clinical event rates in these all-comers patients. There was a high rate of prematurely terminated DAPT, without any effect on MACE at 12 months. This trial is registered with NCT03809715.

Transcatheter aortic valve implantation in patients with uninterrupted vitamin K antagonists.

BACKGROUND: Bridging of vitamin K antagonist (VKA) with heparin is usually not promoted during interventional or surgical procedures related to increased risk of bleeding and thrombotic events but this strategy has not been evaluated during transcatheter aortic valve implantation (TAVI). PURPOSE: The aim of this study was to evaluate the rate of major bleeding and vascular complications after TAVI performed in patients with uninterrupted VKA. METHODS: From January 2016 to October 2017, consecutive patients who underwent TAVI with uninterrupted VKA (International Normalized Ratio [INR] between 1.5 and 3.5) were prospectively included in a monocentric registry. TAVI was performed according to current guidelines and a 50 U/kg bolus of heparin was injected at the beginning of the procedure for all patients. Vascular and bleeding complications were assessed using the Valve Academic Research Consortium 3 (VARC3) and the Bleeding Academic Research Consortium (BARC) definitions at a 30-day follow-up. RESULTS: A total of 88 patients were included with a median age of 84 years (81.8-87.0), 42% being female. The median society of thoracic surgeons score was 5.1 (4.1-7.5), the median CHADS2-VASc was 5.5 (5-6) and 60.2% had a chronic kidney failure. Median INR at the time of implantation was 2.1 (1.8-2.6). The main VKA indication was atrial fibrillation. Transfemoral access was used in 88.6% of the patients. Major bleeding (BARC ≥ 3b) occurred in five patients (5.7%) and major vascular complications occurred in seven patients (8.0%). At 1 month follow-up, major bleeding (BARC ≥ 3) or vascular complications occurred in 10 patients (11.4%). In patients with major bleeding peripheral arterial disease (RR = 10.95; 95% confidence interval (CI) 1.63-73.75; p = 0.014) and carotid access (RR = 8.56; 95% CI 1.19-1.51; p = 0.033) were more common. INR > 2.5 was significantly associated with vascular complications (RR = 7.14; 95% CI 1.29-39.63; p = 0.025). At 30 days, mortality and stroke rates were 2.3% and 4.5%, respectively. CONCLUSION: TAVI with uninterrupted VKA treatment seems feasible and safe with a low risk of major bleeding and vascular complications in this first single-center experience. Particular caution is advocated in high body mass index patients and to keep INR < 2.5.

Percutaneous Repair or Medical Treatment for Secondary Mitral Regurgitation.

BACKGROUND: In patients who have chronic heart failure with reduced left ventricular ejection fraction, severe secondary mitral-valve regurgitation is associated with a poor prognosis. Whether percutaneous mitral-valve repair improves clinical outcomes in this patient population is unknown. METHODS: We randomly assigned patients who had severe secondary mitral regurgitation (defined as an effective regurgitant orifice area of >20 mm2 or a regurgitant volume of >30 ml per beat), a left ventricular ejection fraction between 15 and 40%, and symptomatic heart failure, in a 1:1 ratio, to undergo percutaneous mitral-valve repair in addition to receiving medical therapy (intervention group; 152 patients) or to receive medical therapy alone (control group; 152 patients). The primary efficacy outcome was a composite of death from any cause or unplanned hospitalization for heart failure at 12 months. RESULTS: At 12 months, the rate of the primary outcome was 54.6% (83 of 152 patients) in the intervention group and 51.3% (78 of 152 patients) in the control group (odds ratio, 1.16; 95% confidence interval [CI], 0.73 to 1.84; P=0.53). The rate of death from any cause was 24.3% (37 of 152 patients) in the intervention group and 22.4% (34 of 152 patients) in the control group (hazard ratio, 1.11; 95% CI, 0.69 to 1.77). The rate of unplanned hospitalization for heart failure was 48.7% (74 of 152 patients) in the intervention group and 47.4% (72 of 152 patients) in the control group (hazard ratio, 1.13; 95% CI, 0.81 to 1.56). CONCLUSIONS: Among patients with severe secondary mitral regurgitation, the rate of death or unplanned hospitalization for heart failure at 1 year did not differ significantly between patients who underwent percutaneous mitral-valve repair in addition to receiving medical therapy and those who received medical therapy alone. (Funded by the French Ministry of Health and Research National Program and Abbott Vascular; MITRA-FR ClinicalTrials.gov number, NCT01920698 .).

Use and outcomes of the PK Papyrus covered stent in France: SOS PK Papyrus Registry.

OBJECTIVES: To evaluate the rate of procedural success and long-term outcomes of the PK Papyrus (PKP) covered stent (CS). BACKGROUND: CS are essential in the treatment of coronary artery perforation (CAP). They have also been used to treat coronary artery aneurysms. Limited evidence is available on clinical outcomes with the PKP. METHODS: This was a multicenter, observational, retrospective, and prospective study. Consecutive patients undergoing intentional PKP implantation in 22 centers in France were included. The primary endpoint was the rate of procedural success. Secondary endpoints included rates of death, myocardial infarction (MI), target lesion revascularization (TLR), in-stent restenosis (ISR), and stent thrombosis (ST). RESULTS: Data from 130 patients were analyzed (mean age 72.5 ± 10.5 years; 71% men). The main indication for PKP was CAP, in 84 patients (65%). Delivery success was achieved in 95% and procedural success in 91%. During the in-hospital stay, 15 patients died (12%) and 7 (5%) presented with ST. Data from 127 patients were available at 19.2 ± 12.8 month follow-up. Thirty-three patients died (26%), 15 (12%) had an MI and 21 (17%) presented with TLR. TLR was due to ISR in 12 patients (9%), 10 had definite ST (8%) and 1 patient for stent under-expansion. CONCLUSIONS: The principal indication for PKP was CAP. PKP had high rates of delivery and procedural success. At long-term follow-up, there was a high rate of TLR, mainly due to ISR and ST. These results are consistent with previously reported data in these clinical settings.

Patent Foramen Ovale Closure or Anticoagulation vs. Antiplatelets after Stroke.

BACKGROUND: Trials of patent foramen ovale (PFO) closure to prevent recurrent stroke have been inconclusive. We investigated whether patients with cryptogenic stroke and echocardiographic features representing risk of stroke would benefit from PFO closure or anticoagulation, as compared with antiplatelet therapy. METHODS: In a multicenter, randomized, open-label trial, we assigned, in a 1:1:1 ratio, patients 16 to 60 years of age who had had a recent stroke attributed to PFO, with an associated atrial septal aneurysm or large interatrial shunt, to transcatheter PFO closure plus long-term antiplatelet therapy (PFO closure group), antiplatelet therapy alone (antiplatelet-only group), or oral anticoagulation (anticoagulation group) (randomization group 1). Patients with contraindications to anticoagulants or to PFO closure were randomly assigned to the alternative noncontraindicated treatment or to antiplatelet therapy (randomization groups 2 and 3). The primary outcome was occurrence of stroke. The comparison of PFO closure plus antiplatelet therapy with antiplatelet therapy alone was performed with combined data from randomization groups 1 and 2, and the comparison of oral anticoagulation with antiplatelet therapy alone was performed with combined data from randomization groups 1 and 3. RESULTS: A total of 663 patients underwent randomization and were followed for a mean (±SD) of 5.3±2.0 years. In the analysis of randomization groups 1 and 2, no stroke occurred among the 238 patients in the PFO closure group, whereas stroke occurred in 14 of the 235 patients in the antiplatelet-only group (hazard ratio, 0.03; 95% confidence interval, 0 to 0.26; P<0.001). Procedural complications from PFO closure occurred in 14 patients (5.9%). The rate of atrial fibrillation was higher in the PFO closure group than in the antiplatelet-only group (4.6% vs. 0.9%, P=0.02). The number of serious adverse events did not differ significantly between the treatment groups (P=0.56). In the analysis of randomization groups 1 and 3, stroke occurred in 3 of 187 patients assigned to oral anticoagulants and in 7 of 174 patients assigned to antiplatelet therapy alone. CONCLUSIONS: Among patients who had had a recent cryptogenic stroke attributed to PFO with an associated atrial septal aneurysm or large interatrial shunt, the rate of stroke recurrence was lower among those assigned to PFO closure combined with antiplatelet therapy than among those assigned to antiplatelet therapy alone. PFO closure was associated with an increased risk of atrial fibrillation. (Funded by the French Ministry of Health; CLOSE ClinicalTrials.gov number, NCT00562289 .).

Cyclosporine before PCI in Patients with Acute Myocardial Infarction.

BACKGROUND: Experimental and clinical evidence suggests that cyclosporine may attenuate reperfusion injury and reduce myocardial infarct size. We aimed to test whether cyclosporine would improve clinical outcomes and prevent adverse left ventricular remodeling. METHODS: In a multicenter, double-blind, randomized trial, we assigned 970 patients with an acute anterior ST-segment elevation myocardial infarction (STEMI) who were undergoing percutaneous coronary intervention (PCI) within 12 hours after symptom onset and who had complete occlusion of the culprit coronary artery to receive a bolus injection of cyclosporine (administered intravenously at a dose of 2.5 mg per kilogram of body weight) or matching placebo before coronary recanalization. The primary outcome was a composite of death from any cause, worsening of heart failure during the initial hospitalization, rehospitalization for heart failure, or adverse left ventricular remodeling at 1 year. Adverse left ventricular remodeling was defined as an increase of 15% or more in the left ventricular end-diastolic volume. RESULTS: A total of 395 patients in the cyclosporine group and 396 in the placebo group received the assigned study drug and had data that could be evaluated for the primary outcome at 1 year. The rate of the primary outcome was 59.0% in the cyclosporine group and 58.1% in the control group (odds ratio, 1.04; 95% confidence interval [CI], 0.78 to 1.39; P=0.77). Cyclosporine did not reduce the incidence of the separate clinical components of the primary outcome or other events, including recurrent infarction, unstable angina, and stroke. No significant difference in the safety profile was observed between the two treatment groups. CONCLUSIONS: In patients with anterior STEMI who had been referred for primary PCI, intravenous cyclosporine did not result in better clinical outcomes than those with placebo and did not prevent adverse left ventricular remodeling at 1 year. (Funded by the French Ministry of Health and NeuroVive Pharmaceutical; CIRCUS ClinicalTrials.gov number, NCT01502774; EudraCT number, 2009-013713-99.).

Assessment of the area at risk after acute myocardial infarction using 123I-MIBG SPECT: Comparison with the angiographic APPROACH-score.

BACKGROUND: Assessment of the area at risk (AAR) associated with an acute myocardial infarction is crucial for evaluating prevention and revascularization strategies. The aim of this study was to evaluate whether 123I-metaiodobenzylguanidine (123I-MIBG) single-photon emission computed tomography (SPECT) provides a more widely available assessment of anatomical AAR than the established anatomical angiographic methods. METHODS: Seventy patients with ST-segment elevation acute myocardial infarction (STEMI) underwent coronary angiography with percutaneous coronary intervention and subsequent 123I-MIBG myocardial scintigraphy with left myocardial relative radiotracer uptake evaluation 12 ± 10 days after STEMI. Patients were divided into two groups depending on whether the culprit artery was occluded (50 patients) or sub-occluded (20 patients). Two scores were calculated as a percentage of the left ventricular myocardium surface, the first using a standard 17-segment summed rest score derived from the relative quantitative evaluation of 123I-MIBG myocardial uptake (MAR) and the second using the modified APPROACH-score (ApAR). RESULTS: For the patients with occluded artery, this study showed a high correlation between MAR and the angiographic score (Pearson r = .762 and P < .0001). For the patients with sub-occluded artery, for which the ApAR is not reliable, this study showed no correlation between MAR and the angiographic score (Pearson r = .18 and P = 0.45). CONCLUSIONS: 123I-MIBG myocardial scintigraphy provides ARR assessment similar to that of ApAR in patients with a single occluded coronary artery. However, MAR differs from ApAR when angiographic scores are known to be inaccurate (sub-occluded culprit artery) or impossible to use. Further studies are needed to evaluate the potential clinical interest of 123I-MIBG SPECT as an alternative for area at risk assessment after STEMI even when the culprit artery is sub-occluded or when the angiographic scores cannot be used.

Sustained quality of life improvement after intracoronary injection of autologous bone marrow cells in the setting of acute myocardial infarction: results from the BONAMI trial.

PURPOSE: Cardiac cell therapy is a promising treatment for acute myocardial infarction (AMI), leading to cardiac function improvement. However, whether it translates into quality of life (QoL) improvement is unclear. We hypothesized that administration of bone marrow cells (BMC) to patients with AMI improves QoL. METHODS: In the multicenter BONAMI trial (NCT00200707), patients with reperfused AMI and decreased myocardial viability were randomized to intracoronary autologous BMC infusion (n = 52) or state-of-the-art therapy (n = 49). QoL data, derived from the Minnesota Living with Heart Failure questionnaire (MLHFQ), were obtained 1, 3, and 12 months after AMI and analyzed using a Rasch-family model. RESULTS: Using this model, QoL improved over time in the BMC group (p = 0.025) but not in the control group. Furthermore, the BMC-group patients displayed a better QoL than the control-group patients at 3 and 12 months post-AMI (p = 0.034 and p = 0.003, respectively). These findings were not detected when analyzing MLHFQ data using a standard method. Cardiac function, myocardial viability, mortality, and number of major adverse cardiac events did not differ between treatment groups. CONCLUSION: Our results suggest that BMC therapy can improve QoL, stressing the need for confirmation trials and for systematic QoL assessment in cardiac cell therapy trials .

Predictors of ventricular remodelling in patients with reperfused acute myocardial infarction and left ventricular dysfunction candidates for bone marrow cell therapy: insights from the BONAMI trial.

PURPOSE: Few data are available regarding the relation of left ventricular (LV) mechanical dyssynchrony to remodelling after acute myocardial infarction (MI) and stem cell therapy. We evaluated the 1-year time course of both LV mechanical dyssynchrony and remodelling in patients enrolled in the BONAMI trial, a randomized, multicenter controlled trial assessing cell therapy in patients with reperfused MI. METHODS: Patients with acute MI and ejection fraction (EF) ≤ 45 % were randomized to cell therapy or to control and underwent thallium single-photon emission computed tomography (SPECT), radionuclide angiography, and echocardiography at baseline, 3 months, and 1 year. Eighty-three patients with a comprehensive 1-year follow-up were included. LV dyssynchrony was assessed by the standard deviation (SD) of the LV phase histogram using radionuclide angiography. Remodelling was defined as a 20 % increase in LV end-systolic volume index (LVESVI) at 1 year. RESULTS: At baseline, LVEF, wall motion score index, and perfusion defect size were significantly impaired in the 43 patients (52 %) with LV remodelling (all p < 0.001), without significant increase in LV mechanical dyssynchrony. During follow-up, there was a progressive increase in LV SD (p = 0.01). Baseline independent predictors of LV remodelling were perfusion SPECT defect size (p = 0.001), LVEF (p = 0.01) and a history of hypertension (p = 0.043). Bone marrow cell therapy did not affect the time-course of LV remodelling and dyssynchrony. CONCLUSIONS: LV remodelling 1 year after reperfused MI is associated with progressive LV dyssynchrony and is related to baseline infarct size and ejection fraction, without impact of cell therapy on this process.

Rationale and design of the Cyclosporine to ImpRove Clinical oUtcome in ST-elevation myocardial infarction patients (the CIRCUS trial).

BACKGROUND: Both acute myocardial ischemia and reperfusion contribute to cardiomyocyte death in ST-elevation myocardial infarction (STEMI). The final infarct size is the principal determinant of subsequent clinical outcome in STEMI patients. In a proof-of-concept phase II trial, the administration of cyclosporine prior to primary percutaneous coronary intervention (PPCI) has been associated with a reduction of infarct size in STEMI patients. METHODS: CIRCUS is an international, prospective, multicenter, randomized, double-blinded, placebo-controlled trial. The study is designed to compare the efficacy and safety of cyclosporine versus placebo, in addition to revascularization by PPCI, in patients presenting with acute anterior myocardial infarction within 12 hours of symptoms onset and initial TIMI flow ≤1 in the culprit left anterior descending coronary artery. Patients are randomized in a 1:1 fashion to 2.5 mg/kg intravenous infusion of cyclosporine or matching placebo performed in the minutes preceding PCI. The primary efficacy end point of CIRCUS is a composite of 1-year all-cause mortality, rehospitalization for heart failure or heart failure worsening during initial hospitalization, and left ventricular adverse remodeling as determined by sequential transthoracic echochardiography. Secondary outcomes will be tested using a hierarchical sequence of left ventricular (LV) ejection fraction and absolute measurements of LV volumes. The composite of death and rehospitalization for heart failure or heart failure worsening during initial hospitalization will be further assessed at three years after the initial infarction. RESULTS: Recruitment lasted from April 2011 to February 2014. The CIRCUS trial has recruited 975 patients with acute anterior myocardial infarction. The 12-months results are expected to be available in 2015. CONCLUSIONS: The CIRCUS trial is testing the hypothesis that cyclosporine in addition to early revascularization with PPCI compared to placebo in patients with acute anterior myocardial infarction reduces the incidence of death, heart failure and adverse LV remodeling at one-year follow-up.

The RIPOST-MI study, assessing remote ischemic perconditioning alone or in combination with local ischemic postconditioning in ST-segment elevation myocardial infarction.

Local ischemic postconditioning (IPost) and remote ischemic perconditioning (RIPer) are promising cardioprotective therapies in ST-elevation myocardial infarction (STEMI). We aimed: (1) to investigate whether RIPer initiated at the catheterization laboratory would reduce infarct size, as measured using serum creatine kinase-MB isoenzyme (CK-MB) release as a surrogate marker; (2) to assess if the combination of RIPer and IPost would provide an additional reduction. Patients (n = 151) were randomly allocated to one of the following groups: (1) control group, percutaneous transluminal coronary angioplasty (PTCA) alone; (2) RIPer group, PTCA combined with RIPer, consisting of three cycles of 5-min inflation and 5-min deflation of an upper-arm blood-pressure cuff initiated before reperfusion; (3) RIPer+IPost group, PTCA combined with RIPer and IPost, consisting of four cycles of 1-min inflation and 1-min deflation of the angioplasty balloon. The CK-MB area under the curve (AUC) over 72 h was reduced in RIPer, and RIPer+IPost groups, by 31 and 29 %, respectively, compared to the Control group; however, CK-MB AUC differences between the three groups were not statistically significant (p = 0.06). Peak CK-MB, CK-MB AUC to area at risk (AAR) ratio, and peak CK-MB level to AAR ratio were all significantly reduced in the RIPer and RIPer+IPost groups, compared to the Control group. On the contrary, none of these parameters was significantly different between RIPer+IPost and RIPer groups. To conclude, starting RIPer therapy immediately prior to revascularization was shown to reduce infarct size in STEMI patients, yet combining this therapy with an IPost strategy did not lead to further decrease in infarct size.

Postconditioning attenuates no-reflow in STEMI patients.

After acute myocardial infarction, the presence of no-reflow (or microvascular obstruction: MVO) has been associated with adverse left ventricular (LV) remodeling and worse clinical outcome. This study examined the effects of mechanical ischemic postconditioning on early and late MVO size in acute ST-elevation myocardial infarction (STEMI) patients. Fifty patients undergoing primary coronary angioplasty for a first STEMI with TIMI grade flow 0-1 and no collaterals were randomized to ischemic postconditioning (PC) (n = 25) or control (n = 25) groups. Ischemic PC consisted in the application of four consecutive cycles of a 1-min balloon occlusion, each followed by a 1-min deflation at the onset of reperfusion. Early (3 min post-contrast) and late (10 min post-contrast) MVO size were assessed by contrast-enhanced cardiac-MRI within 96 h after reperfusion. PC was associated with smaller early and late MVO size (3.9 ± 4.8 in PC versus 7.8 ± 6.6% of LV in controls for early MVO, P = 0.02; and 1.8 ± 3.1 in PC versus 4.1 ± 3.9% of LV in controls for late MVO; P = 0.01). This significant reduction was persistent after adjustment for thrombus aspiration, which neither had any significant effect on infarct size, nor on early or late MVO (P = NS for all). Attenuation of MVO was associated to infarct size reduction. Mechanical postconditioning significantly reduces MVO in patients with acute STEMI treated with primary angioplasty.

What is the role of erythropoietin in acute myocardial infarct? Bridging the gap between experimental models and clinical trials.

Erythropoietin (EPO) is the main hormone that regulates erythropoiesis. Beyond its well-known hematopoietic action, EPO has diverse cellular effects in non-hematopoietic tissues. It has been shown to inhibit apoptosis by activating pro-survival pathways in the myocardium, to mobilize endothelial progenitor cells and to inhibit migration of inflammatory cells. EPO has also been shown to have potent pro-angiogenic properties. Numerous experimental data support the cardioprotective effects of EPO in animal models of acute myocardial infarct (AMI). However, these findings are not supported by recent clinical trials designed to investigate the safety and efficacy of EPO in patients with AMI. In this article, we begin by providing a comprehensive review of the cardioprotective effects of EPO in experimental animal models and the molecular mechanisms underlying these effects. We then discuss the EPO data obtained through clinical trials. We compare similarities and differences between the animal and human studies as well as between the different clinical studies in terms of sample size and study design including the dose, the route and the timing of administration as well as confounding factors such as comorbidities and concomitant treatments. Finally, we question the gap between the experimental and the translational clinical data and propose further developments to address these discrepancies and clearly evaluate the role of EPO in the clinical setting of MI.

Heart rate reduction after genetic ablation of L-type Cav1.3 channels induces cardioprotection against ischemia-reperfusion injury.

Background: Acute myocardial infarction (AMI) is the major cause of cardiovascular mortality worldwide. Most ischemic episodes are triggered by an increase in heart rate, which induces an imbalance between myocardial oxygen delivery and consumption. Developing drugs that selectively reduce heart rate by inhibiting ion channels involved in heart rate control could provide more clinical benefits. The Cav1.3-mediated L-type Ca2+ current (ICav1.3) play important roles in the generation of heart rate. Therefore, they can constitute relevant targets for selective control of heart rate and cardioprotection during AMI. Objective: We aimed to investigate the relationship between heart rate and infarct size using mouse strains knockout for Cav1.3 (Cav1.3-/-) L-type calcium channel and of the cardiac G protein gated potassium channel (Girk4-/-) in association with the funny (f)-channel inhibitor ivabradine. Methods: Wild-type (WT), Cav1.3+/-, Cav1.3-/- and Girk4-/- mice were used as models of respectively normal heart rate, moderate heart rate reduction, bradycardia, and mild tachycardia, respectively. Mice underwent a surgical protocol of myocardial IR (40 min ischemia and 60 min reperfusion). Heart rate was recorded by one-lead surface ECG recording, and infarct size measured by triphenyl tetrazolium chloride staining. In addition, Cav1.3-/- and WT hearts perfused on a Langendorff system were subjected to the same ischemia-reperfusion protocol ex vivo, without or with atrial pacing, and the coronary flow was recorded. Results: Cav1.3-/- mice presented reduced infarct size (-29%), while Girk4-/- displayed increased infarct size (+30%) compared to WT mice. Consistently, heart rate reduction in Cav1.3+/- or by the f-channel blocker ivabradine was associated with significant decrease in infarct size (-27% and -32%, respectively) in comparison to WT mice. Conclusion: Our results show that decreasing heart rate allows to protect the myocardium against IR injury in vivo and reveal a close relationship between basal heart rate and IR injury. In addition, this study suggests that targeting Cav1.3 channels could constitute a relevant target for reducing infarct size, since maximal heart rate dependent cardioprotective effect is already observed in Cav1.3+/- mice.

A prospective study comparing short versus standard dual antiplatelet therapy in patients with acute myocardial infarction: design and rationale of the TARGET-FIRST trial.

Based on the latest knowledge and technological advancements, it is still debatable whether a modern revascularisation approach in the setting of acute myocardial infarction (AMI), including complete revascularisation (in patients with significant non-culprit lesions) with newer-generation highly biocompatible drug-eluting stents, requires prolonged dual antiplatelet therapy (DAPT). TARGET-FIRST (ClinicalTrials.gov: NCT04753749) is a prospective, open-label, multicentre, randomised controlled study comparing short (one month) DAPT versus standard (12 months) DAPT in a population of patients with non-ST/ST-segment elevation myocardial infarction, completely revascularised at index or staged procedure (within 7 days), using Firehawk, an abluminal in-groove biodegradable polymer rapamycin-eluting stent. The study will be conducted at approximately 50 sites in Europe. After a mandatory 30-40 days of DAPT with aspirin and P2Y12 inhibitors (preferably potent P2Y12 inhibitors), patients are randomised (1:1) to 1) immediate discontinuation of DAPT followed by P2Y12 inhibitor monotherapy (experimental arm), or 2) continued DAPT with the same regimen (control arm), up until 12 months. With a final sample size of 2,246 patients, the study is powered to evaluate the primary endpoint (non-inferiority of short antiplatelet therapy in completely revascularised patients) for net adverse clinical and cerebral events. If the primary endpoint is met, the study is powered to assess the main secondary endpoint (superiority of short DAPT in terms of major or clinically relevant non-major bleeding). TARGET-FIRST is the first randomised clinical trial to investigate the optimisation of antiplatelet therapy in patients with AMI after achieving complete revascularisation with an abluminal in-groove biodegradable polymer rapamycin-eluting stent implantation.

Delayed postconditioning in the mouse heart in vivo.

BACKGROUND: Reperfusion during acute myocardial infarction remains the best treatment for reducing infarct size. Postconditioning, applied at the onset of reperfusion, reduces myocardial infarction both in animals and humans. The objective of this study was to identify the time delay to apply postconditioning at reperfusion, allowing preservation of cardioprotection in the mouse myocardium. This is a major issue in the management of acute myocardial infarction patients. METHODS AND RESULTS: Mice were subjected to 40 minutes of ischemia and 60 minutes of reperfusion (IR(60')). Postconditioning protocols corresponding to repetitive ischemia (3 cycles of 1 minute of ischemia and 1 minute of reperfusion) were applied during early reperfusion at various time durations (Δt) after reopening of the coronary artery (Δt=10 seconds, 1, 5, 10, 15, 20, 30, and 45 minutes; PostC(Δt)). Infarct size/area at risk was reduced by 71% in PostC(Δ1) compared with IR(60') mice (P=5×10(-6)). There was a linear correlation (r(2)=0.91) between infarct size and Δt, indicating that the cardioprotective effect of delayed postconditioning was progressively attenuated when Δt time increased. The protective effect of PostC(Δ1) and PostC(Δ15) was still effective when the duration of reperfusion was prolonged to 24 hours (IR(24 hours); PostC(Δ1) and PostC(Δ15) versus IR(24 hours), P=0.001). Similar results were obtained for internucleosomal DNA fragmentation and lactate dehydrogenase release. CONCLUSIONS: This study in our in vivo mouse model of myocardial IR shows for the first time that delaying the intervention of postconditioning to 30 minutes does not abrogate the cardioprotective effect of postconditioning. This finding provides evidence that the time window of protection afforded by postconditioning may be larger than initially reported.

Cardioprotection by clopidogrel in acute ST-elevated myocardial infarction patients: a retrospective analysis.

Antiplatelet agents have been extensively used in acute coronary syndromes and improve clinical outcome in STEMI patients. Previous experimental studies of the impact of antiplatelet agents on infarct size have been equivoqual. We questioned whether clopidogrel might reduce infarct size in STEMI patients, independently of any antithrombotic effect, by activating a post-conditioning-like myocardial protection. We retrospectively analyzed three recent controlled, randomized, proof of concept clinical trials aimed at determining whether PCI post-conditioning might attenuated infarct size in STEMI. We addressed whether clopidogrel (300-600 mg before angioplasty) might have influenced infarct size using a multivariable linear regression analysis with infarct size as the continuous outcome variable and age, clopidogrel and GP IIb/IIIa inhibitors, post-conditioning, area at risk, ischemia time, coronary thrombectomy and final TIMI flow, as covariates. In this population of 88 STEMI patients, ischemic post-conditioning and clopidogrel administration were the only two therapeutic independent predictors of the final infarct size as determined by cardiac enzymes release (p = 0.005 and p < 0.0001, respectively) This retrospective analysis supports the proposal that clopidogrel attenuates lethal reperfusion injury.

Intracoronary autologous mononucleated bone marrow cell infusion for acute myocardial infarction: results of the randomized multicenter BONAMI trial.

AIMS: Intracoronary administration of autologous bone marrow cells (BMCs) leads to a modest improvement in cardiac function, but the effect on myocardial viability is unknown. The aim of this randomized multicentre study was to evaluate the effect of BMC therapy on myocardial viability in patients with decreased left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI) and to identify predictive factors for improvement of myocardial viability. METHODS AND RESULTS: One hundred and one patients with AMI and successful reperfusion, LVEF ≤45%, and decreased myocardial viability (resting Tl201-SPECT) were randomized to either a control group (n = 49) or a BMC group (n = 52). Primary endpoint was improvement of myocardial viability 3 months after AMI. Baseline mean LVEF measured by radionuclide angiography was 36.3 ± 6.9%. Bone marrow cell infusion was performed 9.3 ± 1.7 days after AMI. Myocardial viability improved in 16/47 (34%) patients in the BMC group compared with 7/43 (16%) in the control group (P = 0.06). The number of non-viable segments becoming viable was 0.8 ± 1.1 in the control group and 1.2 ± 1.5 in the BMC group (P = 0.13). Multivariate analysis including major post-AMI prognostic factors showed a significant improvement of myocardial viability in BMC vs. control group (P = 0.03). Moreover, a significant adverse role for active smoking (P = 0.04) and a positive trend for microvascular obstruction (P = 0.07) were observed. CONCLUSION: Intracoronary autologous BMC administration to patients with decreased LVEF after AMI was associated with improvement of myocardial viability in multivariate-but not in univariate-analysis. A large multicentre international trial is warranted to further document the efficacy of cardiac cell therapy and better define a group of patients that will benefit from this therapy. CLINICAL TRIAL REGISTRATION INFORMATION: URL: http://www.clinicaltrials.gov. Unique identifier NCT00200707.