Clinical and angiographic outcomes of bioabsorbable vs. permanent polymer drug-eluting stents in Sweden: a report from the Swedish Coronary and Angioplasty Registry (SCAAR).

AIMS: Randomized clinical trials have consistently demonstrated the non-inferiority of bioabsorbable polymer drug-eluting stents (BP-DES) with respect to DES having permanent polymers (PP-DES). To date, the comparative performance of BP- and PP-DES in the real world has not been extensively investigated. METHODS AND RESULTS: From October 2011 to June 2016, we analysed the outcomes associated with newer generation DES use in Sweden. After stratification according to the type of DES received at the index procedure, a total of 16 504 and 79 106 stents were included in the BP- and PP-DES groups, respectively. The Kaplan-Meier estimates for restenosis at 2 years were 1.2% and 1.4% in BP- and PP-DES groups, respectively. Definite stent thrombosis (ST) was low in both groups (0.5% and 0.7% in BP- and PP-DES groups, respectively). The adjusted hazard ratio (HR) for either restenosis or definite ST did not differ between BP- and PP-DES [adjusted HR 0.95, 95% confidence interval (CI) 0.74-1.21; P = 0.670 and adjusted HR 0.79, 95% CI 0.57-1.09; P = 0.151, respectively]. Similarly, there were no differences in the adjusted risk of all-cause death and myocardial infarction (MI) between the two groups (adjusted HR for all-cause death 1.01, 95% CI 0.82-1.25; P = 0.918 and adjusted HR for MI 1.05, 95% CI 0.93-1.19; P = 0.404). CONCLUSION: In a large, nationwide, and unselected cohort of patients, percutaneous coronary intervention with BP-DES implantation was not associated with an incremental clinical benefit over PP-DES use at 2 years follow-up.

Clinical impact of direct stenting and interaction with thrombus aspiration in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention: Thrombectomy Trialists Collaboration.

Aims: Preliminary studies suggest that direct stenting (DS) during percutaneous coronary intervention (PCI) may reduce microvascular obstruction and improve clinical outcome. Thrombus aspiration may facilitate DS. We assessed the impact of DS on clinical outcome and myocardial reperfusion and its interaction with thrombus aspiration among ST-segment elevation myocardial infarction (STEMI) patients undergoing PCI. Methods and results: Patient-level data from the three largest randomized trials on routine manual thrombus aspiration vs. PCI only were merged. A 1:1 propensity matched population was created to compare DS and conventional stenting. Synergy between DS and thrombus aspiration was assessed with interaction P-values in the final models. In the unmatched population (n = 17 329), 32% underwent DS and 68% underwent conventional stenting. Direct stenting rates were higher in patients randomized to thrombus aspiration as compared with PCI only (41% vs. 22%; P < 0.001). Patients undergoing DS required less contrast (162 mL vs. 172 mL; P < 0.001) and had shorter fluoroscopy time (11.1 min vs. 13.3 min; P < 0.001). After propensity matching (n = 10 944), no significant differences were seen between DS and conventional stenting with respect to 30-day cardiovascular death [1.7% vs. 1.9%; hazard ratio 0.88, 95% confidence interval (CI) 0.55-1.41; P = 0.60; Pinteraction = 0.96) and 30-day stroke or transient ischaemic attack (0.6% vs. 0.4%; odds ratio 1.02; 95% CI 0.14-7.54; P = 0.99; Pinteraction = 0.81). One-year results were similar. No significant differences were seen in electrocardiographic and angiographic myocardial reperfusion measures. Conclusion: Direct stenting rates were higher in patients randomized to thrombus aspiration. Clinical outcomes and myocardial reperfusion measures did not differ significantly between DS and conventional stenting and there was no interaction with thrombus aspiration.

Thrombus Aspiration in ST-Segment-Elevation Myocardial Infarction: An Individual Patient Meta-Analysis: Thrombectomy Trialists Collaboration.

BACKGROUND: Thrombus aspiration during percutaneous coronary intervention (PCI) for the treatment of ST-segment-elevation myocardial infarction (STEMI) has been widely used; however, recent trials have questioned its value and safety. In this meta-analysis, we, the trial investigators, aimed to pool the individual patient data from these trials to determine the benefits and risks of thrombus aspiration during PCI in patients with ST-segment-elevation myocardial infarction. METHODS: Included were large (n≥1000), randomized, controlled trials comparing manual thrombectomy and PCI alone in patients with ST-segment-elevation myocardial infarction. Individual patient data were provided by the leadership of each trial. The prespecified primary efficacy outcome was cardiovascular mortality within 30 days, and the primary safety outcome was stroke or transient ischemic attack within 30 days. RESULTS: The 3 eligible randomized trials (TAPAS [Thrombus Aspiration During Percutaneous Coronary Intervention in Acute Myocardial Infarction], TASTE [Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia], and TOTAL [Trial of Routine Aspiration Thrombectomy With PCI Versus PCI Alone in Patients With STEMI]) enrolled 19 047 patients, of whom 18 306 underwent PCI and were included in the primary analysis. Cardiovascular death at 30 days occurred in 221 of 9155 patients (2.4%) randomized to thrombus aspiration and 262 of 9151 (2.9%) randomized to PCI alone (hazard ratio, 0.84; 95% confidence interval, 0.70-1.01; P=0.06). Stroke or transient ischemic attack occurred in 66 (0.8%) randomized to thrombus aspiration and 46 (0.5%) randomized to PCI alone (odds ratio, 1.43; 95% confidence interval, 0.98-2.10; P=0.06). There were no significant differences in recurrent myocardial infarction, stent thrombosis, heart failure, or target vessel revascularization. In the subgroup with high thrombus burden (TIMI [Thrombolysis in Myocardial Infarction] thrombus grade ≥3), thrombus aspiration was associated with fewer cardiovascular deaths (170 [2.5%] versus 205 [3.1%]; hazard ratio, 0.80; 95% confidence interval, 0.65-0.98; P=0.03) and with more strokes or transient ischemic attacks (55 [0.9%] versus 34 [0.5%]; odds ratio, 1.56; 95% confidence interval, 1.02-2.42, P=0.04). However, the interaction P values were 0.32 and 0.34, respectively. CONCLUSIONS: Routine thrombus aspiration during PCI for ST-segment-elevation myocardial infarction did not improve clinical outcomes. In the high thrombus burden group, the trends toward reduced cardiovascular death and increased stroke or transient ischemic attack provide a rationale for future trials of improved thrombus aspiration technologies in this high-risk subgroup. CLINICAL TRIAL REGISTRATION: URLs: http://www.ClinicalTrials.gov http://www.crd.york.ac.uk/prospero/. Unique identifiers: NCT02552407 and CRD42015025936.

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.).

Thrombus aspiration during ST-segment elevation myocardial infarction.

BACKGROUND: The clinical effect of routine intracoronary thrombus aspiration before primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is uncertain. We aimed to evaluate whether thrombus aspiration reduces mortality. METHODS: We conducted a multicenter, prospective, randomized, controlled, open-label clinical trial, with enrollment of patients from the national comprehensive Swedish Coronary Angiography and Angioplasty Registry (SCAAR) and end points evaluated through national registries. A total of 7244 patients with STEMI undergoing PCI were randomly assigned to manual thrombus aspiration followed by PCI or to PCI only. The primary end point was all-cause mortality at 30 days. RESULTS: No patients were lost to follow-up. Death from any cause occurred in 2.8% of the patients in the thrombus-aspiration group (103 of 3621), as compared with 3.0% in the PCI-only group (110 of 3623) (hazard ratio, 0.94; 95% confidence interval [CI], 0.72 to 1.22; P=0.63). The rates of hospitalization for recurrent myocardial infarction at 30 days were 0.5% and 0.9% in the two groups, respectively (hazard ratio, 0.61; 95% CI, 0.34 to 1.07; P=0.09), and the rates of stent thrombosis were 0.2% and 0.5%, respectively (hazard ratio, 0.47; 95% CI, 0.20 to 1.02; P=0.06). There were no significant differences between the groups with respect to the rate of stroke or neurologic complications at the time of discharge (P=0.87). The results were consistent across all major prespecified subgroups, including subgroups defined according to thrombus burden and coronary flow before PCI. CONCLUSIONS: Routine thrombus aspiration before PCI as compared with PCI alone did not reduce 30-day mortality among patients with STEMI. (Funded by the Swedish Research Council and others; ClinicalTrials.gov number, NCT01093404.).

First-in-Man Experience With the ClearLumen Thrombectomy System as an Adjunctive Therapy in Primary Percutaneous Coronary Interventions.

OBJECTIVES: To describe the first-in-man experience with the ClearLumen Thrombectomy System (Walk Vascular, Irvine, CA) and report on its safety, feasibility and efficacy when used as an adjunctive therapy during primary PCI. BACKGROUND: Thrombus aspiration (TA) aims to improve microvascular perfusion but currently available devices are not optimal. METHODS: Prospective, single-centre, non-randomized, safety, and efficacy trial. Patients with acute STEMI were enrolled and the investigational device was used for thrombus aspiration. Safety was evaluated as the overall rate of device related complications while efficacy as the rate of successful device deployment and culprit vessel reperfusion. The composite endpoint based on the achievement of at least two of the following three criteria-TIMI flow 3 and/or myocardial blush grade ≥2 at completion of the case and ST-resolution >70% at 90 minutes after vessel reperfusion-was also evaluated. RESULTS: Over a 3 months period 20 patients were enrolled in the study. Culprit lesion was successfully reached with the investigational device in 19 patients (95%). The pre-specified combined endpoint was met in 16 out of 19 patients (84.2%). Three patients not meeting the combined end point had procedure related, non TA associated, adverse event. Only 2 minor procedural adverse event occurred after thrombus aspiration. CONCLUSIONS: This first-in-man experience with the ClearLumen Thrombectomy System demonstrates initial promising results on safety and efficacy when used as an adjunctive therapy during primary PCI.

Impact of thrombus aspiration during ST-Elevation Myocardial Infarction: a six month composite endpoint and risk of stroke analyses of the TASTE trial.

BACKGROUND: Routine thrombus aspiration during primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI) did not reduce the primary composite endpoint in the "A Randomised Trial of Routine Aspiration ThrOmbecTomy With PCI Versus PCI ALone in Patients With STEMI Undergoing Primary PCI" (TOTAL) trial. We aimed to analyse a similar endpoint in "The Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia" (TASTE) trial up to 180 days. METHODS: In TASTE, 7244 patients with STEMI were randomised to thrombus aspiration followed by PCI or to PCI alone. We analysed the quadruple composite endpoint of cardiovascular death, cardiogenic shock, rehospitalisation for myocardial infarction, or new hospitalisation for heart failure. Furthermore, an extended net-benefit composite endpoint including stent thrombosis, target vessel revascularization or stroke within 180 days was analysed. RESULTS: The primary quadruple composite endpoint occurred in 8.7 % (316 of 3621) in the thrombus aspiration group compared to 9.3 % (338 of 3623) in the PCI alone group (hazard ratio (HR), 0.93; 95 % confidence interval (CI); 0.80 - 1.09, P = 0.36) and the extended net-benefit composite endpoint in 12.0 % (436) vs. 13.2 % (479) (HR, 0.90; 95 % CI; 0.79 - 1.03, P = 0.12). Stroke within 30 days occurred in 0.7 % (27) vs. 0.7 % (24) (HR, 0.89; 95 % CI; 0.51-1.54, P = 0.68). CONCLUSIONS: A large and an extended composite endpoint analysis from the TASTE trial did not demonstrate any clinical benefit of routine thrombus aspiration during PCI in patients with STEMI. There was no evidence of an increased risk of stroke with thrombus aspiration.

Novel Trial Designs: Lessons Learned from Thrombus Aspiration During ST-Segment Elevation Myocardial Infarction in Scandinavia (TASTE) Trial.

In ST-elevation myocardial infarction (STEMI), thrombus material is often present in partial or total coronary occlusion of the coronary vessel. However, prior to the thrombus aspiration during ST-Segment Elevation Myocardial Infarction in Scandinavia (TASTE) trial, it remained unclear whether routine thrombus aspiration during percutaneous coronary intervention (PCI) treatment of STEMI would result in patients overall survival benefit. The TASTE trial was a multicenter, prospective, open-label, randomized, controlled clinical trial. In order to randomize patients to treatment and collect data, the infrastructure of a clinical population-based registry was used. Online data collection used the national comprehensive Swedish Coronary Angiography and Angioplasty Registry, a part of the SWEDEHEART registry. Monitoring and adjudication was done as part of the regular registry validation. There was no separate, dedicated monitoring or adjudication of endpoints. Included were 7244 patients with STEMI with chest pain and time of symptoms to hospital admission <24 h, in addition to new electrocardiographic ST-segment elevation or left bundle-branch block. Exclusion criteria were the need for emergency coronary artery bypass grafting. All-cause mortality at 30 days occurred in 2.8 % of the patients in the thrombus-aspiration group, as compared with 3.0 % in the PCI-only group (hazard ratio [HR] 0.94, 95 % confidence interval [CI] 0.72-1.22; p = 0.63). All-cause mortality at 1 year occurred in 5.3 % of the patients in the thrombus-aspiration group, as compared with 5.6 % in the PCI-only group (HR 0.94, 95 % CI 0.78-1.15; p = 0.57). No patients were lost to follow-up at 1 year. The incremental cost for trial execution was approximately US$ 300,000 or $50 per patient. Routine thrombus aspiration during PCI in patients with STEMI did not reduce the rate of all-cause mortality at 1 year. It is possible to design and conduct mega-trial at only small cost compared to a similar-sized conventional randomized clinical trial.

Repeated epinephrine doses during prolonged cardiopulmonary resuscitation have limited effects on myocardial blood flow: a randomized porcine study.

BACKGROUND: In current guidelines, prolonged cardiopulmonary resuscitation (CPR) mandates administration of repeated intravenous epinephrine (EPI) doses. This porcine study simulating a prolonged CPR-situation in the coronary catheterisation laboratory, explores the effect of EPI-administrations on coronary perfusion pressure (CPP), continuous coronary artery flow average peak velocity (APV) and amplitude spectrum area (AMSA). METHODS: Thirty-six pigs were randomized 1:1:1 to EPI 0.02 mg/kg/dose, EPI 0.03 mg/kg/dose or saline (control) in an experimental cardiac arrest (CA) model. During 15 minutes of mechanical chest compressions, four EPI/saline-injections were administered, and the effect on CPP, APV and AMSA were recorded. Comparisons were performed between the control and the two EPI-groups and a combination of the two EPI-groups, EPI-all. RESULT: Compared to the control group, maximum peak of CPP (Pmax) after injection 1 and 2 was significantly increased in the EPI-all group (p = 0.022, p = 0.016), in EPI 0.02-group after injection 2 and 3 (p = 0.023, p = 0.027) and in EPI 0.03-group after injection 1 (p = 0.013). At Pmax, APV increased only after first injection in both the EPI-all and the EPI 0.03-group compared with the control group (p = 0.011, p = 0.018). There was no statistical difference of AMSA at any Pmax. Seven out of 12 animals (58%) in each EPI-group versus 10 out of 12 (83%) achieved spontaneous circulation after CA. CONCLUSION: In an experimental CA-CPR pig model repeated doses of intravenous EPI results in a significant increase in APV only after the first injection despite increments in CPP also during the following 2 injections indicating inappropriate changes in coronary vascular resistance during subsequent EPI administration.

Transradial versus trans-femoral access site in high-speed rotational atherectomy in Sweden.

BACKGROUND: Radial artery is the preferred access site in contemporary percutaneous coronary intervention (PCI). However, limited data exist regarding utilization pattern, safety, and long-term efficacy of transradial artery access (TRA) PCI in heavily calcified lesions using high-speed rotational atherectomy (HSRA). METHODS: All patients who underwent HSRA-PCI in Sweden between 2005 and 2016 were included. Outcomes were major adverse cardiac events (MACE, including death, myocardial infarction (MI) or target vessel revascularisation (TVR)), in-hospital bleeding and restenosis. Inverse probability of treatment weighting was used to adjust for the non-randomized access site selection. RESULTS: We included 1479 patients of whom 649 had TRA and 782 transfemoral artery access (TFA) HSRA-PCI. The rate of TRA increased significantly by 18% per year but remained lower in HSRA-PCI (60%) than in the overall PCI population (85%) in 2016. TRA was associated with comparable angiographic success but significantly lower risk for major (adjusted OR 0.16; 95% CI 0.05-0.47) or any in-hospital bleeding (adjusted OR 0.32; 95% CI 0.13-0.78). At one year, the adjusted risk for MACE (HR 0.87; 95% CI 0.67-1.13) and its individual components did not differ between TRA and TFA patients. The risk for restenosis did not significantly differ between TRA and TFA HSRA-PCI treated lesions (adjusted HR 0.92; 95% CI 0.46-1.81). CONCLUSION: HSRA-PCI by TRA was associated with significantly lower risk for in-hospital bleeding and equivalent long-term efficacy when compared with TFA. Our data support the feasibility and superior safety profile of TRA in HSRA-PCI.

Pretreatment with heparin in patients with ST-segment elevation myocardial infarction: a report from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR).

BACKGROUND: Unfractionated heparin (UFH) is frequently administered before percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). AIMS: The aim of the study was to investigate if pretreatment with UFH prior to arrival at the catheterisation laboratory affects coronary artery occlusion, mortality, and in-hospital major bleeding in patients with STEMI undergoing PCI. METHODS: Patients with a first STEMI event undergoing PCI between 2008 and 2016 were extracted from the Swedish Coronary Angiography and Angioplasty Registry. Risk ratios for UFH pretreatment versus no pretreatment regarding coronary artery occlusion at presentation in the catheterisation laboratory, 30-day mortality, and bleeding were obtained using adjusted Poisson regression models with robust standard errors. Analyses of propensity score (PS)-matched groups were performed to obtain absolute risk differences. RESULTS: In all, 41,631 patients were included, 16,026 (38%) with and 25,605 (62%) without UFH pretreatment. Adjusted risk ratios were 0.89 (95% confidence interval [CI]: 0.87 to 0.90) for coronary artery occlusion, 0.87 (0.77 to 0.99) for mortality, and 1.01 (0.86 to 1.18) for bleeding. In the PS-matched analyses, the absolute risk differences were -0.087 (-0.074 to -0.099) for coronary artery occlusion, -0.011 (-0.017 to -0.0041) for mortality, and 0 (-0.0052 to 0.0052) for bleeding. CONCLUSIONS: Pretreatment with UFH was associated with a reduction in coronary artery occlusion among patients with STEMI, with a number needed to treat (NNT) of 12, without increasing the risk of major in-hospital bleeding. Regarding mortality, a reduction was found with UFH pretreatment, with an NNT of 94, but this effect was not robust over all sensitivity analyses and residual confounding cannot be excluded.

Trends in Clinical Practice and Outcomes After Percutaneous Coronary Intervention of Unprotected Left Main Coronary Artery.

Background The use of percutaneous coronary intervention (PCI) to treat unprotected left main coronary artery disease has expanded rapidly in the past decade. We aimed to describe nationwide trends in clinical practice and outcomes after PCI for left main coronary artery disease. Methods and Results Patients (n=4085) enrolled in the SCAAR (Swedish Coronary Angiography and Angioplasty Registry) as undergoing PCI for left main coronary artery disease from 2005 to 2017 were included. A count regression model was used to analyze time-related differences in procedural characteristics. The 3-year major adverse cardiovascular and cerebrovascular event rate defined as death, myocardial infarction, stroke, and repeat revascularization was calculated with the Kaplan-Meier estimator and Cox proportional hazard model. The number of annual PCI procedures grew from 121 in 2005 to 589 in 2017 (389%). The increase was greater for men (479%) and individuals with diabetes (500%). Periprocedural complications occurred in 7.9%, decreasing from 10% to 6% during the study period. A major adverse cardiovascular and cerebrovascular event occurred in 35.7% of patients, falling from 45.6% to 23.9% (hazard ratio, 0.56; 95% CI, 0.41-0.78; P=0.001). Radial artery access rose from 21.5% to 74.2% and intracoronary diagnostic procedures from 14.0% to 53.3%. Use of bare-metal stents and first-generation drug-eluting stents fell from 19.0% and 71.9%, respectively, to 0, with use of new-generation drug-eluting stents increasing to 95.2%. Conclusions Recent changes in clinical practice relating to PCI for left main coronary artery disease are characterized by a 4-fold rise in procedures conducted, increased use of evidence-based adjunctive treatment strategies, intracoronary diagnostics, newer stents, and more favorable outcomes.

On the Natural History of Coronary Artery Disease: A Longitudinal Nationwide Serial Angiography Study.

Background The long-term course of coronary atherosclerosis has not been studied in large nationwide cohorts. Understanding the natural history of coronary atherosclerosis could help identify patients at risk for future coronary events. Methods and Results All coronary artery segments with <50% luminal stenosis in patients with a first-time coronary angiogram between 1989 and 2017 were identified (n=2 661 245 coronary artery segments in 248 736 patients) and followed until a clinically indicated angiography within 15 years was performed or until death or end of follow-up (April 2018) using SCAAR (Swedish Coronary Angiography and Angioplasty Registry). The stenosis progression and incidence rates were 2.6% and 1.45 (95% CI, 1.43-1.46) per 1000 segment-years, respectively. The greatest progression rate occurred in the proximal and middle segments of the left anterior descending artery. Male sex and diabetes were associated with a 2-fold increase in risk, and nearly 70% of new stenoses occurred in patients with baseline single-vessel disease (hazard ratio, 3.86 [95% CI, 3.69-4.04]). Coronary artery segments in patients with no baseline risk factors had a progression rate of 0.6% and incidence rate of 0.36 (95% CI, 0.34-0.39), increasing to 8.1% and 4.01 (95% CI, 3.89-4.14) per 1000 segment-years, respectively, in patients with ≥4 risk factors. The prognostic impact of risk factors on stenosis progression was greatest in younger patients and women. Conclusions Coronary atherosclerosis progressed slowly but more frequently in the left coronary artery in men and in the presence of traditional risk factors. Coronary artery segments in patients without risk factors had little or no risk of stenosis progression, and the relative impact of risk factors appears to be of greater importance in younger patients and women. These findings help in the understanding the long-term course of coronary atherosclerosis.

Optimal timing of hypothermia in relation to myocardial reperfusion.

Two previous clinical trials investigating hypothermia as an adjunct therapy for myocardial infarction have failed. Recently a pilot study has demonstrated a significant reduction in infarct size. The aims of this study were to elucidate the effects of hypothermia on reperfusion injury and to investigate the optimal hypothermia protocol for a future clinical trial. Pigs (40-50 kg) were anesthetized and a normal pig temperature of 38°C was established utilizing an endovascular temperature modulating catheter. The pigs were randomized to a combination hypothermia group (1,000 ml of 4°C saline solution and endovascular cooling, n = 8), or to normothermic controls (n = 8). A PCI balloon was then inflated in the LAD for 40 min (control) or 45 min with hypothermia induced during the last 5 min. Furthermore, hypothermia induced by cold saline alone (n = 8), and prolonged combination hypothermia during reperfusion (n = 7) were also examined. Infarct size and area at risk were determined ex vivo after 4 h of reperfusion using gadolinium-enhanced MRI and Tc-99-tetrofosmin SPECT, respectively. All pigs in the combination hypothermia group were cooled to <35°C within 5 min. Combination hypothermia reduced IS/AAR by 18% compared with normothermic controls despite 5 min longer ischemic time (61 ± 5 vs. 74 ± 4%, p = 0.03). Cold saline did not reduce IS/AAR. Prolonging hypothermia treatment after onset of reperfusion by an additional 45 min over that used in a previous paper did not confer any additional benefit. The cardioprotective effects of hypothermia treatment are due to an attenuation of myocardial injury during both ischemia and reperfusion. The results suggest that a hypothermia protocol using a cold saline infusion and endovascular cooling enables hypothermia to be induced in a clinical setting without delaying reperfusion therapy.

Evaluation of coronary blood flow velocity during cardiac arrest with circulation maintained through mechanical chest compressions in a porcine model.

BACKGROUND: Mechanical chest compressions (CCs) have been shown capable of maintaining circulation in humans suffering cardiac arrest for extensive periods of time. Reports have documented a visually normalized coronary blood flow during angiography in such cases (TIMI III flow), but it has never been actually measured. Only indirect measurements of the coronary circulation during cardiac arrest with on-going mechanical CCs have been performed previously through measurement of the coronary perfusion pressure (CPP). In this study our aim was to correlate average peak coronary flow velocity (APV) to CPP during mechanical CCs. METHODS: In a closed chest porcine model, cardiac arrest was established through electrically induced ventricular fibrillation (VF) in eleven pigs. After one minute, mechanical chest compressions were initiated and then maintained for 10 minutes upon which the pigs were defibrillated. Measurements of coronary blood flow in the left anterior descending artery were made at baseline and during VF with a catheter based Doppler flow fire measuring APV. Furthermore measurements of central (thoracic) venous and arterial pressures were also made in order to calculate the theoretical CPP. RESULTS: Average peak coronary flow velocity was significantly higher compared to baseline during mechanical chests compressions and this was observed during the entire period of mechanical chest compressions (12 - 39% above baseline). The APV slowly declined during the 10 min period of mechanical chest compressions, but was still higher than baseline at the end of mechanical chest compressions. CPP was simultaneously maintained at > 20 mmHg during the 10 minute episode of cardiac arrest. CONCLUSION: Our study showed good correlation between CPP and APV which was highly significant, during cardiac arrest with on-going mechanical CCs in a closed chest porcine model. In addition APV was even higher during mechanical CCs compared to baseline. Mechanical CCs can, at minimum, re-establish coronary blood flow in non-diseased coronary arteries during cardiac arrest.

Sealing of Coronary Perforations With a Second-Generation Covered Stent Graft - Results From the PAST-PERF Registry.

BACKGROUND: The PAST-PERF registry was initiated to collect data on the PK Papyrus covered stent, a second-generation device for the treatment of coronary artery perforations with enhanced mechanical properties, but with limited available data. METHODS: Patients treated for coronary artery perforations with the PK Papyrus stent at 14 international centers were retrospectively identified. The primary effectiveness outcome was successful sealing of the perforation. The primary safety outcome was a composite of all-cause mortality, definite or probable stent thrombosis, myocardial infarction and target lesion revascularization. RESULTS: Among the 94 included patients, 72.3% (68/94) had Ellis type III and cavity spilling perforations. Complete sealing was achieved in 93.6% (n = 88), and no sealing could be achieved in 3.2% (n = 3, including one patient with a geographical miss and one patient in whom the device could not be implanted). Pericardiocentesis was required in 25.0% (n = 23), emergency cardiac surgery was needed in 7.6% (n = 7), acute stent thrombosis was observed in 1.1% (n = 1), and in-hospital mortality occurred in 11.7% (n = 11). The median follow-up duration was 283 (IQR:40;670) days. At 6 and 12 months, the incidence of the primary safety endpoint was 26.6% [95%CI:18.6;37.1] and 32.0% [95%CI:22.8;43.4], mortality 15.0% [95%CI:9.0;24.6] and 19.0% [95%CI:11.3;30.0], and target lesion revascularization 5.5% [95%CI:2.0;14.6] and 7.7% [95%CI:3.1;18.2]. Two definite stent thrombosis occurred, one during the procedure and one on post-procedure day 233. CONCLUSIONS: The registry demonstrates favorably high rates of successful stent delivery and sealing of coronary perforations using a second-generation covered stent with low target lesion revascularization and stent thrombosis rates. ANNOTATED TABLE OF CONTENT: The PAST-PERF registry demonstrates favorably high rates of successful stent delivery and sealing of coronary perforations using a second-generation covered stent with low target lesion revascularization and stent thrombosis rates. Specifically, complete sealing was achieved in 93.6% of patients (n = 88/94), and no sealing could be achieved in 3.2% (n = 3, including one patient with a geographical miss and one patient in whom the device could not be implanted). The 12-month mortality was 19.0% [95%CI:11.3;30.0], the rate of target lesion revascularization was 7.7% [95%CI:3.1;18.2], and two definite stent thromboses occurred (one during procedure and one on post-procedure day 233).

Pulmonary blood volume variation decreases after myocardial infarction in pigs: a quantitative and noninvasive MR imaging measure of heart failure.

PURPOSE: To prospectively evaluate the usefulness of magnetic resonance (MR) imaging for estimating pulmonary blood volume (PBV) and the variation in PBV throughout the cardiac cycle in experimental heart failure. MATERIALS AND METHODS: The animal care committee approved this prospective study. Seven pigs were studied before and after myocardial infarction. PBV measurement was validated in a phantom and calculated as the product of cardiac output determined with velocity-encoded MR imaging and the pulmonary transit time for an intravenous bolus of contrast material to pass through the pulmonary circulation. The difference in arterial and venous pulmonary flow during the cardiac cycle was integrated for calculation of the PBV variation (expressed as percentage of stroke volume). Differences were evaluated with the Wilcoxon test. RESULTS: Calculated and direct phantom measurements of PBV differed by a mean of 4% +/- 3 (standard deviation) (R(2) = 0.97, P < .001). Infarction induced a decrease in left ventricular stroke volume (44 mL +/- 6 vs 27 mL +/- 7; P = .02), ejection fraction (55% +/- 5 vs 41% +/- 4; P = .02), and PBV variation (61% +/- 12 vs 43% +/- 15; P = .04) but not PBV (225 mL +/- 23 vs 211 mL +/- 42; P = .50). The mean pulmonary artery pressure increased after infarction (19 mm Hg +/- 6 vs 27 mm Hg +/- 4; P = .04). CONCLUSION: Following infarction, the PBV variation but not PBV decreased. PBV variation was the noninvasive measure exhibiting the greatest percentage of change following infarction. MR imaging can be used to assess the variation of the PBV during the cardiac cycle as a marker of heart failure.

Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia (TASTE trial). A multicenter, prospective, randomized, controlled clinical registry trial based on the Swedish angiography and angioplasty registry (SCAAR) platform. Study design and rationale.

BACKGROUND: In ST-elevation myocardial infarction (STEMI), distal embolization of thrombus material often precludes restoration of normal coronary artery flow. Small-scaled studies have demonstrated that intracoronary thrombus aspiration improves flow and myocardial perfusion, but only one larger randomized single-center study has suggested a survival benefit. Thrombus aspiration is widely used in clinical practice and is recommended by international guidelines despite limited evidence. METHODS/DESIGN: The Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia is a multicenter, prospective, randomized, controlled, clinical open-label trial based on the Swedish angiography and angioplasty registry (SCAAR) platform with blinded evaluation of end points. A total of 5,000 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) will randomly be assigned either to conventional PCI or to thrombus aspiration followed by PCI. SCAAR will be used as the platform for randomization, allowing a broad population of all-comers in the registry network to be enrolled. All follow-up will also be done in SCAAR and other national registries. The primary end point is time to all-cause death at 30 days. DISCUSSION: The Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia trial is the largest trial to date to evaluate the effect of thrombus aspiration on death following PCI in patients with STEMI. We propose the term randomized clinical registry trial to describe the novel entity of using an online national registry as platform for case records, randomization, and follow-up.

Treatment with the C5a receptor antagonist ADC-1004 reduces myocardial infarction in a porcine ischemia-reperfusion model.

BACKGROUND: Polymorphonuclear neutrophils, stimulated by the activated complement factor C5a, have been implicated in cardiac ischemia/reperfusion injury. ADC-1004 is a competitive C5a receptor antagonist that has been shown to inhibit complement related neutrophil activation. ADC-1004 shields the neutrophils from C5a activation before they enter the reperfused area, which could be a mechanistic advantage compared to previous C5a directed reperfusion therapies. We investigated if treatment with ADC-1004, according to a clinically applicable protocol, would reduce infarct size and microvascular obstruction in a large animal myocardial infarct model. METHODS: In anesthetized pigs (42-53 kg), a percutaneous coronary intervention balloon was inflated in the left anterior descending artery for 40 minutes, followed by 4 hours of reperfusion. Twenty minutes after balloon inflation the pigs were randomized to an intravenous bolus administration of ADC-1004 (175 mg, n = 8) or saline (9 mg/ml, n = 8). Area at risk (AAR) was evaluated by ex vivo SPECT. Infarct size and microvascular obstruction were evaluated by ex vivo MRI. The observers were blinded to the treatment at randomization and analysis. RESULTS: ADC-1004 treatment reduced infarct size by 21% (ADC-1004: 58.3 ± 3.4 vs control: 74.1 ± 2.9%AAR, p = 0.007). Microvascular obstruction was similar between the groups (ADC-1004: 2.2 ± 1.2 vs control: 5.3 ± 2.5%AAR, p = 0.23). The mean plasma concentration of ADC-1004 was 83 ± 8 nM at sacrifice. There were no significant differences between the groups with respect to heart rate, mean arterial pressure, cardiac output and blood-gas data. CONCLUSIONS: ADC-1004 treatment reduces myocardial ischemia-reperfusion injury and represents a novel treatment strategy of myocardial infarct with potential clinical applicability.

Apyrase treatment of myocardial infarction according to a clinically applicable protocol fails to reduce myocardial injury in a porcine model.

BACKGROUND: Ectonucleotidase dependent adenosine generation has been implicated in preconditioning related cardioprotection against ischemia-reperfusion injury, and treatment with a soluble ectonucleotidase has been shown to reduce myocardial infarct size (IS) when applied prior to induction of ischemia. However, ectonucleotidase treatment according to a clinically applicable protocol, with administration only after induction of ischemia, has not previously been evaluated. We therefore investigated if treatment with the ectonucleotidase apyrase, according to a clinically applicable protocol, would reduce IS and microvascular obstruction (MO) in a large animal model. METHODS: A percutaneous coronary intervention balloon was inflated in the left anterior descending artery for 40 min, in 16 anesthetized pigs (40-50 kg). The pigs were randomized to 40 min of 1 ml/min intracoronary infusion of apyrase (10 U/ml, n = 8) or saline (0.9 mg/ml, n = 8), twenty minutes after balloon inflation. Area at risk (AAR) was evaluated by ex vivo SPECT. IS and MO were evaluated by ex vivo MRI. RESULTS: No differences were observed between the apyrase group and saline group with respect to IS/AAR (75.7 +/- 4.2% vs 69.4 +/- 5.0%, p = NS) or MO (10.7 +/- 4.8% vs 11.4 +/- 4.8%, p = NS), but apyrase prolonged the post-ischemic reactive hyperemia. CONCLUSION: Apyrase treatment according to a clinically applicable protocol, with administration of apyrase after induction of ischemia, does not reduce myocardial infarct size or microvascular obstruction.