Microarray expression analysis in delayed cardioprotection: the effect of exercise, AICAR, or metformin and the possible role of AMP-activated protein kinase (AMPK).

AMP-activated protein kinase (AMPK) is an enzyme which may be involved in cardioprotective mechanisms in the ischemic heart. Exercise, AICAR, and metformin, all known activators of AMPK, induce delayed cardioprotection which protects the heart against ischemia-reperfusion injury. The objective was to determine the effect of exercise, AICAR, and metformin on gene expression profile and to demonstrate possible interactions in different genes and functions. Rats were divided into either an exercise, AICAR, metformin, or control group. 3, 12, and 24 h after either a single bout of exercise training, a single injection of AICAR or a single dose of metformin, hearts were removed and gene expression profiles were analyzed in tissue from the left ventricle using Affymetrix gene chip probe arrays. Ingenuity Pathway Analysis (IPA) tool was used to analyze the regulated genes for relevant functions and diseases. Each gene chip identified up to 30,000 different probesets of which Ingenuity identified approximately up to 12,000 genes. A total of 147, 304, and 114 different genes in the left ventricle whose expressions were altered >2.0-fold were identified in the exercise, AICAR, and metformin group, respectively. Seventy eight different genes were overlapping the exercise and AICAR group at 24 h. Ingenuity identified six overlapping genes between the exercise, AICAR, and metformin groups including NR4A3, TNFRSF12A, HBB, PENK, PAP, and MAP4K4. IPA software revealed an overabundance of focus molecules in all three intervention groups involving functions related to cell death, cellular growth and proliferation, gene expression and cancer. Exercise, AICAR, and metformin regulate several genes in the rat myocardium with the majority of overlapping genes observed in the exercise and AICAR group. Changes in gene programming mainly involved inflammatory and opioid systems recognized as cardioprotective pathways. Some of these genes may represent possible candidate genes involved in the molecular mechanisms of AMPK-induced delayed PC.

Primary angioplasty versus fibrinolysis in acute myocardial infarction: long-term follow-up in the Danish acute myocardial infarction 2 trial.

BACKGROUND: The Danish Acute Myocardial Infarction 2 (DANAMI-2) study found that primary angioplasty (primary percutaneous coronary intervention [pPCI]) compared with fibrinolysis reduced 30-day adverse events in patients with ST-segment elevation myocardial infarction. The present study investigated whether the benefit of pPCI was maintained at a long-term follow-up. METHODS AND RESULTS: We randomly assigned 1572 patients with ST-segment elevation myocardial infarction-1129 patients at referral hospitals and 443 patients at invasive hospitals-to pPCI or fibrinolysis. Median time from randomization to arrival in the catheterization laboratory for patients admitted to referral hospitals was 67 minutes, with 96% of patients arriving in the catheterization laboratory within 120 minutes. The primary study end point was a composite of death or reinfarction. Median follow-up time was 7.8 years. For the primary end point, 8-year cumulative incidence (1-Kaplan-Meier) was 34.8% in the pPCI group and 41.3% in the fibrinolysis group (hazard ratio, 0.78; 95% confidence interval, 0.66 to 0.92). Reinfarction rates were reduced in the pPCI group (11.7% versus 18.5%; hazard ratio, 0.60; 95% confidence interval, 0.46 to 0.77). Among patients randomized at referral hospitals, pPCI reduced reinfarction (13% versus 18.5%; hazard ratio, 0.66; 95% confidence interval, 0.49 to 0.89) and mortality (26.7% versus 33.3%; hazard ratio, 0.78; 95% confidence interval, 0.63 to 0.97). CONCLUSIONS: The benefit of pPCI over fibrinolysis was maintained at a long-term follow-up. pPCI reduced the risk of reinfarction in the overall cohort and reduced reinfarction and mortality among patients randomized at referral hospitals. This result reinforces that pPCI should be offered to ST-segment elevation myocardial infarction patients when interhospital transport to an invasive hospital can be completed within 120 minutes.

Remote ischemic per-conditioning: a novel therapy for acute stroke?

BACKGROUND AND PURPOSE: Remote ischemic preconditioning is a phenomenon by which a short period of sublethal ischemia to an organ protects against subsequent ischemia in another organ. We have recently demonstrated that remote ischemic conditioning by transient hind limb ischemia delivered during ischemia and before reperfusion can provide potent cardioprotection, a phenomenon we termed per-conditioning. This study evaluated whether remote ischemic per-conditioning may provide neuroprotection in a clinically relevant rat model of acute ischemic stroke. METHODS: Remote ischemic conditioning by transient limb ischemia was used in a rat transient middle cerebral artery occlusion model of acute stroke. A total of 39 P60 rats were randomly allocated to receive preconditioning, per-conditioning, or sham conditioning. Cerebral ischemia was maintained for 120 minutes followed by reperfusion. The resulting infarct size at 24 hours was quantified using computerized image analysis of 2-3-5-triphenyl tetrazolium chloride-stained brain sections. RESULTS: Compared with control, both pre- and per-conditioning significantly reduced brain infarct size with the more clinically relevant per-conditioning stimulus being superior to preconditioning. CONCLUSIONS: Remote per-conditioning by transient limb ischemia is a facile, clinically relevant stimulus that provides potent neuroprotection in a model of regional brain ischemia-reperfusion injury. Further studies are required to better understand the mechanisms and biology of this response before translation to randomized controlled trials of remote per-conditioning for acute ischemic stroke.

Remote ischaemic conditioning before hospital admission, as a complement to angioplasty, and effect on myocardial salvage in patients with acute myocardial infarction: a randomised trial.

BACKGROUND: Remote ischaemic preconditioning attenuates cardiac injury at elective surgery and angioplasty. We tested the hypothesis that remote ischaemic conditioning during evolving ST-elevation myocardial infarction, and done before primary percutaneous coronary intervention, increases myocardial salvage. METHODS: 333 consecutive adult patients with a suspected first acute myocardial infarction were randomly assigned in a 1:1 ratio by computerised block randomisation to receive primary percutaneous coronary intervention with (n=166 patients) versus without (n=167) remote conditioning (intermittent arm ischaemia through four cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff). Allocation was concealed with opaque sealed envelopes. Patients received remote conditioning during transport to hospital, and primary percutaneous coronary intervention in hospital. The primary endpoint was myocardial salvage index at 30 days after primary percutaneous coronary intervention, measured by myocardial perfusion imaging as the proportion of the area at risk salvaged by treatment; analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00435266. FINDINGS: 82 patients were excluded on arrival at hospital because they did not meet inclusion criteria, 32 were lost to follow-up, and 77 did not complete the follow-up with data for salvage index. Median salvage index was 0.75 (IQR 0.50-0.93, n=73) in the remote conditioning group versus 0.55 (0.35-0.88, n=69) in the control group, with median difference of 0.10 (95% CI 0.01-0.22; p=0.0333); mean salvage index was 0.69 (SD 0.27) versus 0.57 (0.26), with mean difference of 0.12 (95% CI 0.01-0.21; p=0.0333). Major adverse coronary events were death (n=3 per group), reinfarction (n=1 per group), and heart failure (n=3 per group). INTERPRETATION: Remote ischaemic conditioning before hospital admission increases myocardial salvage, and has a favourable safety profile. Our findings merit a larger trial to establish the effect of remote conditioning on clinical outcomes. FUNDING: Fondation Leducq.

Antithrombotic therapy and outcomes of patients with atrial fibrillation following primary percutaneous coronary intervention: results from the APEX-AMI trial.

AIMS: To assess the incidence and timing of atrial fibrillation (AF), describe antithrombotic therapy use, and evaluate the association of AF with 90 day mortality and other secondary clinical outcomes. METHODS AND RESULTS: We studied 5745 ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention (PCI) in APEX-AMI. Approximately 11% had AF during hospitalization. Atrial fibrillation prevalence at baseline and at discharge was 4.8% [confidence interval (CI) 4.3-5.4%] and 2.5% (CI 2.1-2.9%), respectively. The proportion of 5466 patients without AF at baseline who developed new onset AF was 6.3% (CI 5.6-6.9%). This corresponded to 9.3 cases of new onset AF/1000 patient days at risk. New onset AF was independently associated with 90 day mortality [adjusted hazard ratio (HR) 1.81; 95% CI 1.06-3.09; P = 0.029] after accounting for baseline covariates and in-hospital procedures and complications. New onset AF was associated with shock (adjusted HR 3.81; 95% CI 1.88-7.70; P = 0.0002), congestive heart failure (adjusted HR 2.66; 95% CI 1.74-4.06; P < 0.0001), and stroke (adjusted HR 2.98; 95% CI 1.47-6.04; P = 0.0024) in models accounting for baseline covariates. Of AF patients, 55% did not receive oral anticoagulation therapy at discharge. Among patients with coronary stents, 5.1% were discharged on triple therapy. Patients at highest risk of stroke (CHADS(2) score > or =2) were least likely to receive oral anticoagulation at discharge (39%). Warfarin use in patients with AF at discharge (43.4%) was associated with lower rates of 90 day mortality and stroke. CONCLUSION: Atrial fibrillation prevalence at baseline and at discharge was 4.8 and 2.5%, respectively. The proportion of patients who developed new onset AF was 6.3%. New onset AF was independently associated with 90 day mortality and was a marker of adverse outcomes in patients undergoing primary PCI.

Infarct size and myocardial salvage after primary angioplasty in patients presenting with symptoms for <12 h vs. 12-72 h.

AIMS: Primary angioplasty for ST-segment elevation myocardial infarction (STEMI) is recommended only if symptom duration is <12 h. We evaluated final infarct size (FIS) and myocardial salvage in early presenters (<12 h) vs. late presenters (12-72 h) undergoing primary angioplasty. METHODS AND RESULTS: Myocardial perfusion imaging (MPI) was performed acutely to assess area at risk (AAR) before angioplasty and repeated after 30 days to assess FIS (% of LV myocardium), salvage index (% non-infarcted AAR), and left ventricular ejection fraction (LVEF). Late presenters (n = 55) compared with early presenters (n = 341) had larger median FIS [14% (inter-quartile range 3-30) vs. 7% (2-18), P = 0.005], lower salvage index [53% (27-89) vs. 69% (45-91), P = 0.05], and lower LVEF [48% (44-58%) vs. 53% (47-59), P = 0.04]. However, FIS, salvage index, and LVEF correlated weakly with symptom duration (R(2)-values <0.10). In patients with TIMI-flow 0 (n = 247), late presenters had lower salvage index than early presenters [44% (23-73) vs. 57% (42-86), P = 0.03], but substantial salvage (>50% of AAR) was observed in 41% of late presenters despite total infarct-artery occlusion. CONCLUSION: FIS is larger in late presenters (>12 h) than early presenters after primary angioplasty for STEMI. However, substantial myocardial salvage can be obtained beyond the 12 h limit, even when the infarct-related artery is totally occluded.

Blockage of receptor for advanced glycation end products prevents development of cardiac dysfunction in db/db type 2 diabetic mice.

AIMS: Activation of the receptor for advanced glycation end products (RAGE) is associated with long-term complications in diabetes mellitus. In this study, we tested whether RAGE activation in the diabetic myocardium is implicated in the development of cardiac dysfunction. METHODS AND RESULTS: Using MRI and conductance catheter techniques, we evaluated cardiac function in a type 2 diabetic mouse model (db/db), and assessed the effect of blocking RAGE with a RAGE antibody. Gene expressions were evaluated in samples of myocardial tissue. Diabetic db/db mice demonstrated an accelerated age-dependent deterioration in cardiac function associated with altered expression of genes related to cardiac structure and function. Blockage of RAGE signalling prevented the reduction in systolic function (preload recruitable stroke work: 109.8 +/- 13.8 vs. 94.5 +/- 14.9 mmHg/microL, P = 0.04) and development of increased LV diastolic chamber stiffness (0.18 +/- 0.05 vs. 0.27 +/- 0.07 mmHg, P = 0.01). The cardiac expression of collagen (col1a1) was reduced by approximately 45% and the expression of myosin was switched from the foetal isoform (MHCbeta) to the adult isoform (MHCalpha). CONCLUSION: Activation of RAGE is a significant pathogenetic mechanism for the development of cardiac dysfunction in type 2 diabetes. The underlying mechanisms involve not only the passive biophysical properties of the myocardium but also myocyte function.

Evaluation of the relationship between hyperinsulinaemia and myocardial ischaemia/reperfusion injury in a rat model of depression.

Major depression is associated with medical co-morbidity, such as ischaemic heart disease and diabetes, but the underlying pathophysiological mechanisms remain unclear. The FSL (Flinders Sensitive Line) rat is a genetic animal model of depression exhibiting features similar to those of depressed individuals. The aim of the present study was to compare the myocardial responsiveness to I/R (ischaemia/reperfusion) injury and the effects of IPC (ischaemic preconditioning) in hearts from FSL rats using SD (Sprague-Dawley) rats as controls and to characterize differences in glucose metabolism and insulin sensitivity between FSL and SD rats. Hearts were perfused in a Langendorff model and were subjected or not to IPC before 40 min of global ischaemia, followed by 120 min of reperfusion. Myocardial infarct size was found to be significantly larger in the FSL rats than in the SD rats following I/R injury (62.4+/-4.2 compared with 46.9+/-2.9%; P<0.05). IPC reduced the infarct size (P<0.01) and improved haemodynamic function (P<0.01) in both FSL and SD rats. No significant difference was found in blood glucose levels between the two groups measured after 12 h of fasting, but fasting plasma insulin (70.1+/-8.9 compared with 40.9+/-4.7 pmol/l; P<0.05) and the HOMA (homoeostatic model assessment) index (P<0.01) were significantly higher in FSL rats compared with SD rats. In conclusion, FSL rats had larger infarct sizes following I/R injury and were found to be hyperinsulinaemic compared with SD rats, but appeared to have a maintained cardioprotective mechanism against I/R injury, as IPC reduced infarct size in these rats. This animal model may be useful in future studies when examining the mechanisms that contribute to the cardiovascular complications associated with depression.

Clinical reinfarction according to infarct location and reperfusion modality in patients with ST elevation myocardial infarction. A DANAMI-2 long-term follow-up substudy.

OBJECTIVES: To evaluate clinical reinfarction during a 3-year follow-up after randomization to primary angioplasty versus fibrinolysis in anterior and non-anterior ST elevation myocardial infarction (STEMI). METHODS: Clinical reinfarction was prospectively assessed by an endpoint committee blinded to the study treatment. RESULTS: At 30 days, primary angioplasty compared with fibrinolysis reduced the reinfarction rate both in anterior STEMI patients (n = 823; 2.5 vs. 5.6%, p = 0.02) and in non-anterior STEMI patients (n = 743; 0.8 vs. 7.4%, p < 0.001). After 3 years, the reduction in reinfarction rate was no longer present in anterior STEMI patients (11.2 vs. 11.2%, p = 0.86), but persisted in non-anterior STEMI patients (5.2 vs. 13.5%, p < 0.001). Reinfarction after anterior STEMI carried a higher mortality than reinfarction after non-anterior STEMI (37.6 vs. 15.3%, p = 0.01). Independent predictors of death were: age [hazard ratio (HR) per 1-year increase in age = 1.08 (1.07-1.09)], clinical reinfarction [HR = 5.15 (3.57-7.43)], anterior index STEMI [HR = 1.65 (1.24-2.19)], and Killip class > or =2 [HR = 1.42 (1.01-2.00)]. The additional late reinfarctions after angioplasty for anterior STEMI were located within the angioplasty-treated target segment. Anterior STEMI patients had smaller mean target vessel diameter, which was associated with reinfarction. CONCLUSIONS: Clinical reinfarction is an independent predictor of death. The early superiority of primary angioplasty over fibrinolysis on reinfarction rate after anterior STEMI diminished during long-term follow-up.

The Danish multicentre randomized study of fibrinolytic therapy vs. primary angioplasty in acute myocardial infarction (the DANAMI-2 trial): outcome after 3 years follow-up.

BACKGROUND: The DANAMI-2 trial showed that in patients with ST-elevation myocardial infarction (STEMI), a strategy of inter-hospital transfer for primary angioplasty was superior to on-site fibrinolysis at 30 days follow-up. This paper reports on the pre-specified long-term composite endpoint at 3 years follow-up in DANAMI-2. METHODS AND RESULTS: We randomized 1572 patients with STEMI to primary angioplasty or intravenous alteplase; 1129 patients were enrolled at 24 referral hospitals and 443 patients at 5 angioplasty centres. Ninety-six percent of inter-hospital transfers for angioplasty were completed within 2 h. No patients were lost to follow-up. The composite endpoint (death, clinical re-infarction, or disabling stroke) was reduced by angioplasty when compared with fibrinolysis at 3 years (19.6 vs. 25.2%, P =0.006). For patients transferred to angioplasty compared with those receiving on-site fibrinolysis, the composite endpoint occurred in 20.1 vs. 26.7% (P = 0.007), death in 13.6 vs. 16.4% (P = 0.18), clinical re-infarction in 8.9 vs. 12.3% (P = 0.05), and disabling stroke in 3.2 vs. 4.7% (P = 0.23). CONCLUSION: The benefit of transfer for primary angioplasty based on the composite endpoint was sustained after 3 years. For patients with characteristics as those in DANAMI-2, primary angioplasty should be the preferred treatment strategy when inter-hospital transfer can be completed within 2 h.

Impact of type 2 diabetes on nitric oxide and adrenergic modulation of myocardial perfusion.

Type 2 diabetic patients are characterized by a reduced adenosine-induced hyperemic myocardial perfusion, which may contribute to their increased cardiovascular morbidity. We hypothesized that the reduced hyperemia can be explained by functional changes in endothelial or autonomic nervous regulation. In 12 type 2 diabetic patients without signs of ischemic heart disease and 14 age-matched control subjects, myocardial perfusion was measured at rest, during adenosine, and during adenosine and alpha-receptor blockade (phentolamine) using positron emission tomography on two separate days: 1) with, and 2) without nitric oxide (NO) inhibition with N(G)-nitro-L-arginine methyl ester. Myocardial perfusion during adenosine was lower in type 2 diabetic patients compared with control subjects (P = 0.05). No significant effect of NO inhibition on myocardial perfusion during adenosine was found in any of the groups. In control subjects, alpha-receptor blockade increased hyperemic myocardial vascular resistance during NO inhibition, whereas no effect was observed in type 2 diabetic patients. At rest, a significant correlation was observed between rate-pressure product and myocardial perfusion in control subjects. NO inhibition and type 2 diabetes abolished this correlation. Endothelial and cardiac autonomic nerve function seems to play only a minimal role in the reduced hyperemic myocardial perfusion in type 2 diabetic patients. However, the linear correlation between resting perfusion and cardiac work appears to be abolished in type 2 diabetes and during NO synthase inhibition.

Cardioprotection by L-glutamate during postischaemic reperfusion: reduced infarct size and enhanced glycogen resynthesis in a rat insulin-free heart model.

1. Previously, we found that administration of high-dose L-glutamate during postischaemic reperfusion improves haemodynamic recovery and enhances glycogen resynthesis. In the present study, we investigated whether the same effect occurs in an insulin-free model and whether glutamate administration reduces infarct size. Further, we studied whether the cardioprotective effect of glutamate depends on preserved glutamate transamination and K(ATP) channel activity. 2. In a rat isolated, insulin-free, perfused heart model, we compared the effects of administration of L-glutamate (10 mmol/L) during either 45 min no-flow regional ischaemia plus 120 min reperfusion or reperfusion alone on infarct size and left ventricular (LV) recovery. The effect of glutamate on glycogen metabolism was studied in a model of 30 min global no-flow ischaemia and 60 min reperfusion. In both models, the effects of inhibition of glutamate transamination and K(ATP) channel activity were examined by adding amino-oxyacetate (an aminotransferase inhibitor; 0.1 mmol/L) and glibenclamide (a K(ATP) blocker; 10 mmol/L), respectively. 3. Administration of L-glutamate reduced infarct size by 60% (P < 0.01) and improved postischaemic LV function (developed pressure and rate pressure product; P < 0.05). L-Glutamate increased glycogen content after 60 min reperfusion by 65% (P < 0.01). Amino-oxyacetate, as well as glibenclamide, abolished the glutamate-mediated reduction in infarct size, haemodynamic improvement and glycogen resynthesis during reperfusion. 4. In conclusion, L-glutamate administration from the start of postischaemic reperfusion exerts cardioprotective effects, including reduced infarct size, improved haemodynamic recovery and enhanced glycogen resynthesis. These effects depend on preserved transamination of glutamate and K(ATP) channel activity, but not on insulin administration.

A comparison of coronary angioplasty with fibrinolytic therapy in acute myocardial infarction.

BACKGROUND: For the treatment of myocardial infarction with ST-segment elevation, primary angioplasty is considered superior to fibrinolysis for patients who are admitted to hospitals with angioplasty facilities. Whether this benefit is maintained for patients who require transportation from a community hospital to a center where invasive treatment is available is uncertain. METHODS: We randomly assigned 1572 patients with acute myocardial infarction to treatment with angioplasty or accelerated treatment with intravenous alteplase; 1129 patients were enrolled at 24 referral hospitals and 443 patients at 5 invasive-treatment centers. The primary study end point was a composite of death, clinical evidence of reinfarction, or disabling stroke at 30 days. RESULTS: Among patients who underwent randomization at referral hospitals, the primary end point was reached in 8.5 percent of the patients in the angioplasty group, as compared with 14.2 percent of those in the fibrinolysis group (P=0.002). The results were similar among patients who were enrolled at invasive-treatment centers: 6.7 percent of the patients in the angioplasty group reached the primary end point, as compared with 12.3 percent in the fibrinolysis group (P=0.05). Among all patients, the better outcome after angioplasty was driven primarily by a reduction in the rate of reinfarction (1.6 percent in the angioplasty group vs. 6.3 percent in the fibrinolysis group, P<0.001); no significant differences were observed in the rate of death (6.6 percent vs. 7.8 percent, P=0.35) or the rate of stroke (1.1 percent vs. 2.0 percent, P=0.15). Ninety-six percent of patients were transferred from referral hospitals to an invasive-treatment center within two hours. CONCLUSIONS: A strategy for reperfusion involving the transfer of patients to an invasive-treatment center for primary angioplasty is superior to on-site fibrinolysis, provided that the transfer takes two hours or less.

Revascularization compared to medical treatment in patients with silent vs. symptomatic residual ischemia after thrombolyzed myocardial infarction--the DANAMI study.

AIMS: The aim was to compare the effect of revascularization to conservative treatment in patients with residual silent and with residual symptomatic ischemia following acute myocardial infarction (AMI). The study was a subanalysis of the DANAMI (DANish AMI) randomized study of invasive vs. conservative treatment in patients with inducible ischemia after thrombolysis in AMI. METHODS AND RESULTS: One thousand and eight patients were randomized to invasive or conservative treatment, stratified by the type of ischemia: silent, i.e. ST depression during an exercise test prior to discharge in 56%, or symptomatic, i.e. chest pain occurring either spontaneously during admission or during the exercise test, with or without ST changes, in 44%. Compared to a conservative strategy, invasive treatment reduced the incidence of nonfatal reinfarction, after in median 2.4 years, in both symptomatic patients (13.3-7.2%, p < 0.006) and patients with silent ischemia (10.1 vs. 5.7%, p < 0.05), and of admissions with unstable angina in symptomatic (44.5-27.6%, p < 0.0001) and silent ischemia (21.6-13.3%, p < 0.0006). CONCLUSIONS: Compared to conservative strategy, invasive treatment reduces the risk of nonfatal reinfarction and hospital admissions for unstable angina in thrombolyzed post-AMI patients with silent as well as symptomatic exercise-induced ischemia.

Impact of type 2 diabetes on myocardial insulin sensitivity to glucose uptake and perfusion in patients with coronary artery disease.

BACKGROUND AND HYPOTHESIS: Myocardial insulin resistance (IR) is a feature of coronary artery disease (CAD) with reduced left ventricular ejection fraction (LVEF). Whether type 2 diabetes mellitus (T2DM) with CAD and preserved LVEF induces myocardial IR and whether insulin in these patients acts as a myocardial vasodilator is debated. METHODS: We studied 27 CAD patients (LVEF > 50%): 12 with T2DM (CAD+DM), 15 without T2DM (CAD-NoDM). Regional myocardial and skeletal glucose uptake, myocardial and skeletal muscle perfusion were measured with positron emission tomography. Myocardial muscle perfusion was measured at rest and during hyperemia in nonstenotic and stenotic regions with and without acute hyperinsulinemia. RESULTS: Myocardial glucose uptake was similar in CAD+DM and CAD-NoDM in both nonstenotic and stenotic regions [0.38 +/- 0.08 and 0.36 +/- 0.11 micromol/g.min; P value nonsignificant (NS)] and (0.35 +/- 0.09 and 0.37 +/- 0.13 micromol/g.min; P = NS). Skeletal glucose uptake was reduced in CAD+DM (0.05 +/- 0.04 vs. 0.10 +/- 0.05 micromol/g.min; P = 0.02), and likewise, whole-body glucose uptake was reduced in CAD+DM (4.0 +/- 2.8 vs. 7.0 +/- 2.4 mg/kg.min; P = 0.01). Insulin did not alter myocardial muscle perfusion at rest or during hyperemia. Insulin increased skeletal muscle perfusion in CAD-NoDM (0.11 +/- 0.03 vs. 0.06 +/- 0.03 ml/g.min; P = 0.02), but not in CAD+DM (0.08 +/- 0.04 and 0.09 +/- 0.05 ml/g.min; P = NS). CONCLUSION: Myocardial IR to glucose uptake is not an inherent feature in T2DM patients with preserved LVEF. Acute physiological insulin exposure exerts no coronary vasodilation in CAD patients irrespective of T2DM.

Does diabetes mellitus abolish the beneficial effect of primary coronary angioplasty on long-term risk of reinfarction after acute ST-segment elevation myocardial infarction compared with fibrinolysis? (A DANAMI-2 substudy).

Little is known about the effect of diabetes mellitus on long-term clinical outcome after primary percutaneous coronary intervention (pPCI) compared with fibrinolysis in patients who have acute ST-elevation myocardial infarction. We analyzed 3-year clinical outcome in diabetic patients and nondiabetic patients who had been randomized to fibrinolysis or pPCI in the DANAMI-2 trial to compare long-term clinical outcome. The primary end point was a composite of death, clinical reinfarction, or disabling stroke. Median follow-up was 3.8 years. Among 1,572 consecutive patients who had ST-elevation myocardial infarction and were randomized to pPCI or fibrinolysis, 173 (11.0%) had diabetes mellitus; 60 of these patients received metformin treatment and were excluded. After 3 years no difference was found between diabetic patients who underwent pPCI versus fibrinolysis (combined event p=0.37, reinfarction p=0.06 in favor of fibrinolysis), whereas pPCI was superior to fibrinolysis in nondiabetic patients (combined event p=0.002, clinical reinfarction p<0.001). Three-year incidence of clinical reinfarction analyzed with Cox's regression showed that pPCI compared with fibrinolysis increased the relative risk of clinical reinfarction in diabetic patients (relative risk 2.57, 95% confidence interval 1.48 to 4.46, p <0.001) but decreased the risk in nondiabetic patients (relative risk 0.52, 95% confidence interval 0.36 to 0.74, p<0.001). In conclusion, from the DANAMI-2 trial we hypothesize that diabetes may abolish the beneficial effect of pPCI on long-term risk of clinical reinfarction.

Lack of acute cardioprotective effect from preischaemic erythropoietin administration in a porcine coronary occlusion model.

BACKGROUND: Recombinant human erythropoietin (rhEPO) has been proposed to possess important tissue protective, apart from haematopoietic, effects. Cardioprotective effects have thus been reported in rodents exposed to myocardial ischaemia. Pathways common to the mediation of ischaemic preconditioning may be involved. Before clinical testing such possible cardioprotective effects needs assessment in an experimental large animal model with closer similarity to human ischaemic pathophysiology. METHODS: A control group and two rhEPO groups were studied. EPO1 pigs were given EPO corresponding to the early window and EPO2 pigs to the early and late window of ischaemic preconditioning in a closed chest, catheter-based, porcine coronary occlusion model (45 min of occlusion of the left anterior descending artery). Infarct size as a proportion of the ischaemic area (IS/AAR) was measured in vivo by myocardial perfusion imaging (MPI) and postmortem by a histochemical procedure (at 150 min of reperfusion). RESULTS: IS/AAR did not differ significantly between control (C), EPO1 and EPO2 groups, neither measured by MPI (mean+/-SD for C: 0.87+/-0.13; EPO1: 0.92+/-0.08; EPO2: 0.87+/-0.11), nor histochemically (mean+/-SD for C: 0.64+/-0.20; EPO1: 0.75+/-0.17; EPO2: 0.80+/-0.07). In the EPO2 group mean arterial pulmonary pressure and dP/dtmax were increased compared with control group. CONCLUSION: Despite promising results from studies in rodents, rhEPO did not reduce infarct size measured after 2.5 h of reperfusion in our porcine model.

Myocardial perfusion imaging with 99mTc sestamibi early after reperfusion reliably reflects infarct size reduction by ischaemic preconditioning in an experimental porcine model.

OBJECTIVE: Reliable methods for assessment of tissue reperfusion early after revascularizing therapy for acute myocardial infarction are needed. Myocardial perfusion imaging with Tc sestamibi (MIBI MPI) may serve this purpose. Usage during early reperfusion may be problematic e.g. due to ischaemic preconditioning (IP), which is important in inducing ischaemic tolerance. It is mediated through the opening of mitochondrial K ATP channels, reducing mitochondrial membrane potential. This may, as well as ischaemia per se, affect cellular uptake of Tc sestamibi. We therefore studied the reliability of MIBI MPI during early reperfusion as a measure of infarct size and its reduction by ischaemic preconditioning. METHODS AND RESULTS: We compared MIBI MPI (cut-off, 45% of maximum pixel count) with a histochemical method in a porcine model, nine controls and eight IP pigs, using 45 min catheter based coronary occlusion of the left anterior descending artery. Infarct size (IS) was determined relative to the area at risk (AAR). The relative infarct size (IS/AAR) after 120 min reperfusion estimated by MPI was 0.83 (0.17) in controls vs 0.07 (0.12) in the IP group (mean (SD), P<0.001). The corresponding values for histochemistry were controls 0.77 (0.19) vs IP 0.07 (0.11), P<0.001. IS/AAR measured by MPI and histochemistry were correlated significantly (r=0.93, P<0.001). Furthermore, IS relative to left ventricular mass (IS/LV) determined by autoradiography and histochemistry correlated (r=0.93, P<0.001). MPI overestimated IS/LV and AAR/LV by approximately a factor of 2 compared with histochemistry or autoradiography. CONCLUSION: MIBI MPI during early reperfusion is a reliable measure of relative infarct size reduction after ischaemic preconditioning, supporting use for stratification for adjunctive therapy and for assessment of prognosis.

Global left ventricular longitudinal systolic strain for early risk assessment in patients with acute myocardial infarction treated with primary percutaneous intervention.

BACKGROUND: Left ventricular systolic function is a key determinant of outcome after ST-segment elevation myocardial infarction (STEMI). The aim of this study was to study speckle-tracking global longitudinal strain (GLS) for early risk evaluation in STEMI and compare it with left ventricular ejection fraction (LVEF), wall motion score index (WMSI), and end-systolic volume index (ESVI). METHODS: Five-hundred seventy-six patients underwent echocardiography ≤24 hours after primary percutaneous coronary intervention for STEMI. The end point was the composite of death, hospitalization with reinfarction, congestive heart failure, or stroke. Associations with outcome were assessed by multivariate Cox regression with adjustment for clinical parameters. Hazard ratios (HRs) for events within the first year are reported per absolute percentage GLS increase. RESULTS: During a median follow-up period of 24 months, 162 patients experienced at least one event. GLS was associated with the composite end point (adjusted HR, 1.20; 95% confidence interval [CI], 1.12-1.29) and also when controlling for LVEF (adjusted HR, 1.17; 95% CI, 1.07-1.29) and ESVI (adjusted HR, 1.18; 95% CI, 1.08-1.28). Although WMSI was significantly associated with outcome beyond any association accounted for by GLS, a borderline significant association was found after controlling for WMSI (adjusted HR for GLS, 1.10; 95% CI, 1.00-1.21). When GLS or WMSI was known, there was no significant association between LVEF or ESVI and outcome. CONCLUSIONS: In a large population of patients with STEMI, GLS and WMSI were comparable and both superior for early risk assessment compared with volume-based left ventricular function indicators such as LVEF and ESVI. Compared with WMSI, the advantage of GLS is the provision of a semiautomated quantitative measure.

Sex- and age-related differences in clinical outcome after primary percutaneous coronary intervention.

AIMS: To compare the outcome after primary percutaneous coronary intervention (PPCI) according to sex and age, including comparison of sex- and age-specific mortality of PPCI patients with that of the general population. METHODS AND RESULTS: This population-based follow-up study included 7,385 STEMI patients treated with PPCI and 42,965 matched general population controls. The primary outcome was the composite endpoint of mortality, reinfarction, and stroke at 30 days, one year, and two years. Women were older and had a more adverse baseline risk profile than men. The risks of the composite endpoint after 30 days, one year, and two years were 9.1%, 16.0%, and 20.0%, respectively, for women compared to 5.8%, 10.6%, and 14.0% for men (adjusted hazard ratio [HR] [30 days]=1.16 [0.95-1.41], adjusted HR [one year]=1.18 [1.02-1.37], and adjusted HR [two years]=1.14 [0.99-1.30]). The risk of an adverse outcome increased similarly among women and men with increasing age. When comparing patients and controls, we found a higher mortality among patients up to 90 days after PPCI. However, after 90 days, the mortality among the PPCI patients was comparable to the mortality in the general population in all sex and age groups. CONCLUSIONS: Clinical outcome after PPCI was comparable in men and women after controlling for possible confounding. After 90 days post-PPCI, the mortality of treated patients was comparable to the mortality of the general population, independent of sex and age.