Matthias Götberg

Outcomes 1 Year after Thrombus Aspiration for Myocardial Infarction

BACKGROUND Routine intracoronary thrombus aspiration before primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) has not been proved to reduce short-term mortality. We evaluated clinical outcomes at 1 year after thrombus aspiration. METHODS We randomly assigned 7244 patients with STEMI to undergo manual thrombus aspiration followed by PCI or to undergo PCI alone, in a registry-based, randomized clinical trial. The primary end point of all-cause mortality at 30 days has been reported previously. Death from any cause at 1 year was a prespecified secondary end point of the trial. RESULTS No patients were lost to follow-up. Death from any cause occurred in 5.3% of the patients (191 of 3621 patients) in the thrombus-aspiration group, as compared with 5.6% (202 of 3623) in the PCI-only group (hazard ratio, 0.94; 95% confidence interval [CI], 0.78 to 1.15; P=0.57). Rehospitalization for myocardial infarction at 1 year occurred in 2.7% and 2.7% of the patients, respectively (hazard ratio, 0.97; 95% CI, 0.73 to 1.28; P=0.81), and stent thrombosis in 0.7% and 0.9%, respectively (hazard ratio, 0.84; 95% CI, 0.50 to 1.40; P=0.51). The composite of death from any cause, rehospitalization for myocardial infarction, or stent thrombosis occurred in 8.0% and 8.5% of the patients, respectively (hazard ratio, 0.94; 95% CI, 0.80 to 1.11; P=0.48). The results were consistent across all the major subgroups, including grade of thrombus burden and coronary flow before PCI. CONCLUSIONS Routine thrombus aspiration before PCI in patients with STEMI did not reduce the rate of death from any cause or the composite of death from any cause, rehospitalization for myocardial infarction, or stent thrombosis at 1 year. (Funded by the Swedish Research Council and others; TASTE ClinicalTrials.gov number, NCT01093404.).

A Pilot Study of Rapid Cooling by Cold Saline and Endovascular Cooling Before Reperfusion in Patients With ST-Elevation Myocardial Infarction

Background—Experimental studies have shown that induction of hypothermia before reperfusion of acute coronary occlusion reduces infarct size. Previous clinical studies, however, have not been able to show this effect, which is believed to be mainly because therapeutic temperature was not reached before reperfusion in the majority of the patients. We aimed to evaluate the safety and feasibility of rapidly induced hypothermia by infusion of cold saline and endovascular cooling catheter before reperfusion in patients with acute myocardial infarction. Methods and Results—Twenty patients with acute myocardial infarction scheduled to undergo primary percutaneous coronary intervention were enrolled in this prospective, randomized study. After 4±2 days, myocardium at risk and infarct size were assessed by cardiac magnetic resonance using T2-weighted imaging and late gadolinium enhancement imaging, respectively. A core body temperature of <35°C (34.7±0.3°C) was achieved before reperfusion without significant delay in door-to-balloon time (43±7 minutes versus 40±6 minutes, hypothermia versus control, P=0.12). Despite similar duration of ischemia (174±51 minutes versus 174±62 minutes, hypothermia versus control, P=1.00), infarct size normalized to myocardium at risk was reduced by 38% in the hypothermia group compared with the control group (29.8±12.6% versus 48.0±21.6%, P=0.041). This was supported by a significant decrease in both peak and cumulative release of Troponin T in the hypothermia group (P=0.01 and P=0.03, respectively). Conclusions—The protocol demonstrates the ability to reach a core body temperature of <35°C before reperfusion in all patients without delaying primary percutaneous coronary intervention and that combination hypothermia as an adjunct therapy in acute myocardial infarction may reduce infarct size at 3 days as measured by MRI. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00417638.

Cardiospecific microRNA Plasma Levels Correlate with Troponin and Cardiac Function in Patients with ST Elevation Myocardial Infarction, Are Selectively Dependent on Renal Elimination, and Can Be Detected in Urine Samples

Objectives: Circulating microRNAs (miRNAs) are promising as biomarkers for various diseases. We examined the release patterns of cardiospecific miRNAs in a closed-chest, large animal ischemia-reperfusion model and in patients with ST elevation myocardial infarction (STEMI). Methods: Six anesthetized pigs were subjected to coronary occlusion-reperfusion. Plasma, urine, and clinical parameters were collected from 25 STEMI patients undergoing primary percutaneous coronary intervention. miRNA was extracted and measured with qPCR. Results: In the pig reperfusion model miR-1, miR-133a, and miR-208b increased rapidly in plasma with a peak at 120 min, while miR-499-5p remained elevated longer. In patients with STEMI all 4 miRNAs increased abruptly from 70-fold to 3,000-fold in plasma, with a peak within 12 h (p < 0.01). miR-1 and miR-133a both correlated strongly with the glomerular filtration rate (GFR), indicating renal elimination. This was confirmed by detection of miR-1 and miR-133a, but not miR-208b or miR-499-5p, in urine. Peak values of miR-208b correlated with peak troponin and the ejection fraction. Conclusion: We demonstrate a distinct and rapid increase in levels of cardiospecific miRNA in the circulation after myocardial infarction. Release of miRNAs correlated with cardiomyocyte necrosis markers, the ejection fraction, and the GFR, indicating a possible role for these molecules as biomarkers for the diagnosis of STEMI as well as the prediction of long-term complications.

Instantaneous Wave-free Ratio versus Fractional Flow Reserve to Guide PCI

Background The instantaneous wave‐free ratio (iFR) is an index used to assess the severity of coronary‐artery stenosis. The index has been tested against fractional flow reserve (FFR) in small trials, and the two measures have been found to have similar diagnostic accuracy. However, studies of clinical outcomes associated with the use of iFR are lacking. We aimed to evaluate whether iFR is noninferior to FFR with respect to the rate of subsequent major adverse cardiac events. Methods We conducted a multicenter, randomized, controlled, open‐label clinical trial using the Swedish Coronary Angiography and Angioplasty Registry for enrollment. A total of 2037 participants with stable angina or an acute coronary syndrome who had an indication for physiologically guided assessment of coronary‐artery stenosis were randomly assigned to undergo revascularization guided by either iFR or FFR. The primary end point was the rate of a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization within 12 months after the procedure. Results A primary end‐point event occurred in 68 of 1012 patients (6.7%) in the iFR group and in 61 of 1007 (6.1%) in the FFR group (difference in event rates, 0.7 percentage points; 95% confidence interval [CI], ‐1.5 to 2.8; P=0.007 for noninferiority; hazard ratio, 1.12; 95% CI, 0.79 to 1.58; P=0.53); the upper limit of the 95% confidence interval for the difference in event rates fell within the prespecified noninferiority margin of 3.2 percentage points. The results were similar among major subgroups. The rates of myocardial infarction, target‐lesion revascularization, restenosis, and stent thrombosis did not differ significantly between the two groups. A significantly higher proportion of patients in the FFR group than in the iFR group reported chest discomfort during the procedure. Conclusions Among patients with stable angina or an acute coronary syndrome, an iFR‐guided revascularization strategy was noninferior to an FFR‐guided revascularization strategy with respect to the rate of major adverse cardiac events at 12 months. (Funded by Philips Volcano; iFR SWEDEHEART ClinicalTrials.gov number, NCT02166736.)

ADP Acting on P2Y13 Receptors Is a Negative Feedback Pathway for ATP Release From Human Red Blood Cells

Red blood cells may regulate tissue circulation and O2 delivery by releasing the vasodilator ATP in response to hypoxia. When released extracellularly, ATP is rapidly degraded to ADP in the circulation by ectonucleotidases. In this study, we show that ADP acting on P2Y13 receptors on red blood cells serves as a negative feedback pathway for the inhibition of ATP release. mRNA of the ADP receptor P2Y13 was highly expressed in human red blood cells and reticulocytes. The stable ADP analogue 2-MeSADP decreased ATP release from red blood cells by inhibition of cAMP. The P2Y12 and P2Y13 receptor antagonist AR-C67085 (30 &mgr;mol/L), but not the P2Y1 blocker MRS2179, inhibited the effects of 2-MeSADP. At doses where AR-C67085 only blocks P2Y12 (100 nmol/L), it had no effect. AR-C67085 and the nucleotidase apyrase increased cAMP per se, indicating a constant cAMP inhibitory effect of endogenous extracellular ADP. 2-MeSADP reduced plasma ATP concentrations in an in vivo pig model. Our results indicate that the ATP degradation product ADP inhibits ATP release by acting on the red blood cell P2Y13 receptor. This negative feedback system could be important in the control of plasma ATP levels and tissue circulation.

Rapid short-duration hypothermia with cold saline and endovascular cooling before reperfusion reduces microvascular obstruction and myocardial infarct size

BackgroundThe aim of this study was to evaluate the combination of a rapid intravenous infusion of cold saline and endovascular hypothermia in a closed chest pig infarct model.MethodsPigs were randomized to pre-reperfusion hypothermia (n = 7), post-reperfusion hypothermia (n = 7) or normothermia (n = 5). A percutaneous coronary intervention balloon was inflated in the left anterior descending artery for 40 min. Hypothermia was started after 25 min of ischemia or immediately after reperfusion by infusion of 1000 ml of 4°C saline and endovascular hypothermia. Area at risk was evaluated by in vivo SPECT. Infarct size was evaluated by ex vivo MRI.ResultsPre-reperfusion hypothermia reduced infarct size/area at risk by 43% (46 ± 8%) compared to post-reperfusion hypothermia (80 ± 6%, p < 0.05) and by 39% compared to normothermia (75 ± 5%, p < 0.05). Pre-reperfusion hypothermia infarctions were patchier in appearance with scattered islands of viable myocardium. Pre-reperfusion hypothermia abolished (0%, p < 0.001), and post-reperfusion hypothermia significantly reduced microvascular obstruction (10.3 ± 5%; p < 0.05), compared to normothermia: (30.2 ± 5%).ConclusionRapid hypothermia with cold saline and endovascular cooling before reperfusion reduces myocardial infarct size and microvascular obstruction. A novel finding is that hypothermia at the onset of reperfusion reduces microvascular obstruction without reducing myocardial infarct size. Intravenous administration of cold saline combined with endovascular hypothermia provides a method for a rapid induction of hypothermia suggesting a potential clinical application.

Stent thrombosis in new-generation drug-eluting stents in patients with STEMI undergoing primary PCI: a report from SCAAR.

BACKGROUND Some concerns still have not been resolved about the long-term safety of drug-eluting stents (DES) in patients with acute STEMI. OBJECTIVES The aim of this study was to evaluate the stent thrombosis (ST) rate up to 3 years in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (PCI) with new-generation drug-eluting stents (n-DES) compared with bare-metal stents (BMS) and old-generation drug-eluting stents (o-DES) enrolled in the SCAAR (Swedish Coronary Angiography and Angioplasty Registry). METHODS From January 2007 to January 2013, 34,147 patients with STEMI were treated by PCI with n-DES (n = 4,811), o-DES (n = 4,271), or BMS (n = 25,065). The risks of early/late (up to 1 year) and very late definite ST (after 1 year) were estimated. RESULTS Cox regression landmark analysis showed a significantly lower risk of early/late ST in patients treated with n-DES (hazard ratio [HR]: 0.65; 95% confidence interval [CI]: 0.43 to 0.99; p = 0.04) and o-DES (HR: 0.60; 95% CI: 0.41 to 0.89; p = 0.01) compared with the BMS group. The risk of very late ST was similar between the n-DES and BMS groups (HR: 1.52; 95% CI: 0.78 to 2.98; p = 0.21), whereas a higher risk of very late ST was observed with o-DES compared with BMS (HR: 2.88; 95% CI: 1.70 to 4.89; p < 0.01). CONCLUSIONS Patients treated with n-DES have a lower risk of early/late ST than patients treated with BMS. The risk of very late ST is low and comparable between n-DES and BMS up to 3 years of follow-up, whereas o-DES treatment is associated with an increased risk of very late ST. The current STEMI guidelines might require an update in light of the results of this and other recent studies.

Mild hypothermia reduces acute mortality and improves hemodynamic outcome in a cardiogenic shock pig model.

INTRODUCTION Cardiogenic shock is the main cause of death in patients hospitalized due to an acute myocardial infarction. Mild hypothermia reduces metabolism and could offer protective effects for this condition. The aim of our study was to investigate if mild therapeutic hypothermia would improve outcome and hemodynamic parameters in an ischemic cardiogenic shock pig model. METHODS Twenty-five pigs (40-50 kg) were anesthetized and a normothermic temperature of 38 degrees C was established utilising an endovascular cooling catheter in a closed-chest model. A Swan-Ganz catheter was placed in the pulmonary artery. Hemodynamic parameters were continuously monitored and blood gases were sampled every 30 min. Ischemia was induced by inflation of a PCI balloon in proximal LAD for 40 min. Sixteen pigs that have fulfilled predefined shock criteria were randomized to hypothermia (n=8), or normothermia (n=8). Hypothermia (33 degrees C) was induced after onset of reperfusion by using an endovascular temperature modulating catheter and was maintained until termination of the experiment. RESULTS The pigs in the hypothermia group were cooled to <34 degrees C in approximately 45 min. 5/8 pigs in the normothermia group died while all pigs in the hypothermia group survived (p<0.01). Stroke volume and blood pressure were significantly higher in the hypothermia group (p<0.05), whereas heart rate was significantly lower in the hypothermia group (p=0.01). Cardiac output did not differ among the groups (p=0.13). Blood gas analysis revealed higher mixed venous oxygen saturation, pH, and base excess in the hypothermia group indicating less development of metabolic acidosis (p<0.05). CONCLUSIONS In this pig model, mild therapeutic hypothermia reduces acute mortality in cardiogenic shock, improves hemodynamic parameters and reduces metabolic acidosis. These findings suggest a possible clinical benefit of therapeutic hypothermia for patients with acute cardiogenic shock.

Bivalirudin versus Heparin Monotherapy in Myocardial Infarction

BACKGROUND The comparative efficacy of various anticoagulation strategies has not been clearly established in patients with acute myocardial infarction who are undergoing percutaneous coronary intervention (PCI) according to current practice, which includes the use of radial‐artery access for PCI and administration of potent P2Y12 inhibitors without the planned use of glycoprotein IIb/IIIa inhibitors. METHODS In this multicenter, randomized, registry‐based, open‐label clinical trial, we enrolled patients with either ST‐segment elevation myocardial infarction (STEMI) or non‐STEMI (NSTEMI) who were undergoing PCI and receiving treatment with a potent P2Y12 inhibitor (ticagrelor, prasugrel, or cangrelor) without the planned use of glycoprotein IIb/IIIa inhibitors. The patients were randomly assigned to receive bivalirudin or heparin during PCI, which was performed predominantly with the use of radial‐artery access. The primary end point was a composite of death from any cause, myocardial infarction, or major bleeding during 180 days of follow‐up. RESULTS A total of 6006 patients (3005 with STEMI and 3001 with NSTEMI) were enrolled in the trial. At 180 days, a primary end‐point event had occurred in 12.3% of the patients (369 of 3004) in the bivalirudin group and in 12.8% (383 of 3002) in the heparin group (hazard ratio, 0.96; 95% confidence interval [CI], 0.83 to 1.10; P=0.54). The results were consistent between patients with STEMI and those with NSTEMI and across other major subgroups. Myocardial infarction occurred in 2.0% of the patients in the bivalirudin group and in 2.4% in the heparin group (hazard ratio, 0.84; 95% CI, 0.60 to 1.19; P=0.33), major bleeding in 8.6% and 8.6%, respectively (hazard ratio, 1.00; 95% CI, 0.84 to 1.19; P=0.98), definite stent thrombosis in 0.4% and 0.7%, respectively (hazard ratio, 0.54; 95% CI, 0.27 to 1.10; P=0.09), and death in 2.9% and 2.8%, respectively (hazard ratio, 1.05; 95% CI, 0.78 to 1.41; P=0.76). CONCLUSIONS Among patients undergoing PCI for myocardial infarction, the rate of the composite of death from any cause, myocardial infarction, or major bleeding was not lower among those who received bivalirudin than among those who received heparin monotherapy. (Funded by the Swedish Heart–Lung Foundation and others; VALIDATE‐SWEDEHEART ClinicalTrialsRegister.eu number, 2012–005260–10; ClinicalTrials.gov number, NCT02311231.)

Real-time use of instantaneous wave–free ratio: Results of the ADVISE in-practice: An international, multicenter evaluation of instantaneous wave–free ratio in clinical practice

Objectives To evaluate the first experience of real-time instantaneous wave–free ratio (iFR) measurement by clinicians. Background The iFR is a new vasodilator-free index of coronary stenosis severity, calculated as a trans-lesion pressure ratio during a specific period of baseline diastole, when distal resistance is lowest and stable. Because all previous studies have calculated iFR offline, the feasibility of real-time iFR measurement has never been assessed. Methods Three hundred ninety-two stenoses with angiographically intermediate stenoses were included in this multicenter international analysis. Instantaneous wave–free ratio and fractional flow reserve (FFR) were performed in real time on commercially available consoles. The classification agreement of coronary stenoses between iFR and FFR was calculated. Results Instantaneous wave–free ratio and FFR maintain a close level of diagnostic agreement when both are measured by clinicians in real time (for a clinical 0.80 FFR cutoff: area under the receiver operating characteristic curve [ROCAUC] 0.87, classification match 80%, and optimal iFR cutoff 0.90; for a ischemic 0.75 FFR cutoff: iFR ROCAUC 0.90, classification match 88%, and optimal iFR cutoff 0.85; if the FFR 0.75-0.80 gray zone is accounted for: ROCAUC 0.93, classification match 92%). When iFR and FFR are evaluated together in a hybrid decision-making strategy, 61% of the population is spared from vasodilator while maintaining a 94% overall agreement with FFR lesion classification. Conclusion When measured in real time, iFR maintains the close relationship to FFR reported in offline studies. These findings confirm the feasibility and reliability of real-time iFR calculation by clinicians.