Clinical Impact of Intraprocedural Stent Thrombosis During Percutaneous Coronary Intervention in Patients Treated With Potent P2Y12 inhibitors - a VALIDATE-SWEDEHEART Substudy

Background

The clinical importance of intraprocedural stent thrombosis (IPST) during percutaneous coronary intervention in the contemporary era of potent oral P2Y12 inhibitors is not established. The aim of this study was to assess IPST and its association with clinical outcome in patients with myocardial infarction undergoing percutaneous coronary intervention with contemporary antithrombotic medications.

Methods and Results

The VALIDATE‐SWEDEHEART study (Bivalirudin Versus Heparin in ST‐Segment and Non–ST‐Segment Elevation Myocardial Infarction in Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence‐Based Care in Heart Disease Evaluated According to Recommended Therapies Registry Trial) included 6006 patients with myocardial infarction, treated with potent P2Y12 inhibitors during percutaneous coronary intervention. IPST, defined as a new or worsening thrombus related to a stent deployed during the procedure, was reported by the interventional cardiologist in 55 patients (0.9%) and was significantly associated with ST‐segment elevation myocardial infarction presentation, longer stents, bailout glycoprotein IIb/IIIa inhibitors, and final Thrombolysis in Myocardial Infarction flow <3. The primary composite end point included cardiovascular death, myocardial infarction, out‐of‐laboratory definite stent thrombosis and target vessel revascularization within 30 days. Secondary end points were major bleeding and the individual components of the primary composite end point. Patients with versus without IPST had significantly higher rates of the primary composite end point (20.0% versus 4.4%), including higher rates of cardiovascular death, target vessel revascularization, and definite stent thrombosis, but not myocardial infarction or major bleeding. By multivariable analysis, IPST was independently associated with the primary composite end point (hazard ratio, 3.82; 95% CI, 2.05–7.12; P<0.001).

Conclusions

IPST is a rare but dangerous complication during percutaneous coronary intervention, independently associated with poor prognosis, even in the current era of potent antiplatelet agents. Future treatment studies are needed to reduce the rate of IPST and to improve the poor outcome among these patients.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02311231.

Incidence and outcome of myocardial infarction treated with percutaneous coronary intervention during COVID-19 pandemic

Objective

Most reports on the declining incidence of myocardial infarction (MI) during the COVID-19 have either been anecdotal, survey results or geographically limited to areas with lockdowns. We examined the incidence of MI during the COVID-19 pandemic in Sweden, which has remained an open society with a different public health approach fighting COVID-19.

Methods

We assessed the incidence rate (IR) as well as the incidence rate ratios (IRRs) of all MI referred for coronary angiography in Sweden using the nationwide Swedish Coronary Angiography and Angioplasty Registry (SCAAR), during the COVID-19 pandemic in Sweden (1 March 2020–7 May 2020) in relation to the same days 2015–2019.

Results

A total of 2443 MIs were referred for coronary angiography during the COVID-19 pandemic resulting in an IR 36 MIs/day (204 MIs/100 000 per year) compared with 15 213 MIs during the reference period with an IR of 45 MIs/day (254 MIs/100 000 per year) resulting in IRR of 0.80, 95% CI (0.74 to 0.86), p<0.001. Results were consistent in all investigated patient subgroups, indicating no change in patient category seeking cardiac care. Kaplan-Meier event rates for 7-day case fatality were 439 (2.3%) compared with 37 (2.9%) (HR: 0.81, 95% CI (0.58 to 1.13), p=0.21). Time to percutaneous coronary intervention (PCI) was shorter during the pandemic and PCI was equally performed, indicating no change in quality of care during the pandemic.

Conclusion

The COVID-19 pandemic has significantly reduced the incidence of MI referred for invasive treatment strategy. No differences in overall short-term case fatality or quality of care indicators were observed.

Radial versus femoral access in patients with acute coronary syndrome undergoing invasive management: A prespecified subgroup analysis from VALIDATE-SWEDEHEART

AIMS

In the Bivalirudin versus Heparin in ST-Segment and Non-ST-Segment Elevation Myocardial Infarction in Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated according to Recommended Therapies Registry Trial (VALIDATE-SWEDEHEART), bivalirudin was not superior to unfractionated heparin in patients with acute coronary syndrome undergoing invasive management. We assessed whether the access site had an impact on the primary endpoint of death, myocardial infarction or major bleeding at 180 days and whether it interacted with bivalirudin/unfractionated heparin.

METHODS AND RESULTS

A total of 6006 patients with acute coronary syndrome planned for percutaneous coronary intervention were randomised to either bivalirudin or unfractionated heparin. Arterial access was left to the operator discretion. Overall, 90.5% of patients underwent transradial access and 9.5% transfemoral access. Baseline risk was higher in transfemoral access. The unadjusted hazard ratio for the primary outcome was lower with transradial access (hazard ratio 0.53, 95% confidence interval 0.43-0.67, p<0.001) and remained lower after multivariable adjustment (hazard ratio 0.56, 95% confidence interval 0.52-0.84, p<0.001). Transradial access was associated with lower risk of death (hazard ratio 0.41, 95% confidence interval 0.28-0.60, p<0.001) and major bleeding (hazard ratio 0.57, 95% confidence interval 0.44-0.75, p<0.001). There was no interaction between treatment with bivalirudin and access site for the primary endpoint (p=0.976) or major bleeding (p=0.801).

CONCLUSIONS

Transradial access was associated with lower risk of death, myocardial infarction or major bleeding at 180 days. Bivalirudin was not associated with less bleeding, irrespective of access site.

Bivalirudin versus heparin monotherapy in non-ST-segment elevation myocardial infarction

BACKGROUND

The optimal anti-coagulation strategy for patients with non-ST-elevation myocardial infarction treated with percutaneous coronary intervention is unclear in contemporary clinical practice of radial access and potent P2Y12-inhibitors. The aim of this study was to investigate whether bivalirudin was superior to heparin monotherapy in patients with non-ST-elevation myocardial infarction without routine glycoprotein IIb/IIIa inhibitor use.

METHODS

In a large pre-specified subgroup of the multicentre, prospective, randomised, registry-based, open-label clinical VALIDATE-SWEDEHEART trial we randomised patients with non-ST-elevation myocardial infarction undergoing percutaneous coronary intervention, treated with ticagrelor or prasugrel, to bivalirudin or heparin monotherapy with no planned use of glycoprotein IIb/IIIa inhibitors during percutaneous coronary intervention. The primary endpoint was the rate of a composite of all-cause death, myocardial infarction or major bleeding within 180 days.

RESULTS

A total of 3001 patients with non-ST-elevation myocardial infarction, were enrolled. The primary endpoint occurred in 12.1% (182 of 1503) and 12.5% (187 of 1498) of patients in the bivalirudin and heparin groups, respectively (hazard ratio of bivalirudin compared to heparin treatment 0.96, 95% confidence interval 0.78-1.18, p=0.69). The results were consistent in all major subgroups. All-cause death occurred in 2.0% versus 1.7% (hazard ratio 1.15, 0.68-1.94, p=0.61), myocardial infarction in 2.3% versus 2.5% (hazard ratio 0.91, 0.58-1.45, p=0.70), major bleeding in 8.9% versus 9.1% (hazard ratio 0.97, 0.77-1.24, p=0.82) and definite stent thrombosis in 0.3% versus 0.2% (hazard ratio 1.33, 0.30-5.93, p=0.82).

CONCLUSION

Bivalirudin as compared to heparin during percutaneous coronary intervention for non-ST-elevation myocardial infarction did not reduce the composite of all-cause death, myocardial infarction or major bleeding in non-ST-elevation myocardial infarction patients receiving current recommended treatments with modern P2Y12-inhibitors and predominantly radial access.

Tailored nurse-led cardiac rehabilitation after myocardial infarction results in better risk factor control at one year compared to traditional care: a retrospective observational study

BACKGROUND

Cardiac rehabilitation improves prognosis after an acute myocardial infarction (AMI), however, the optimal method of implementation is unknown. The aim of the study was to evaluate the effect of individually-tailored, nurse-led cardiac rehabilitation on patient outcomes.

METHOD

This single-centre retrospective observational study included 217 patients (62 ± 9 years, 73% men). All patients attended cardiac rehabilitation including at least two follow-up consultations with a nurse. Patients receiving traditional care (n = 105) had a routine cardiologist consultation, while for those receiving tailored care (n = 112) their need for a cardiologist consultation was individually evaluated by the nurses. Regression analysis was used to analyse risk factor control and hospital readmissions at one year.

RESULTS

Patients in the tailored group achieved better control of total cholesterol (- 0.1 vs + 0.4 mmol/L change between baseline (time of index event) and 12-14-month follow-up, (p = 0.01), LDL cholesterol (- 0.1 vs + 0.2 mmol/L, p = 0.02) and systolic blood pressure (- 2.1 vs + 4.3 mmHg, p = 0.01). Active smokers, at baseline, were more often smoke-free at one-year in the tailored group [OR 0.32 (0.1-1.0), p = 0.05]. There was a no significant difference in re-admissions during the first year of follow-up. In the tailored group 60% of the patients had a cardiologist consultation compared to 98% in the traditional group (p < 0.001). The number of nurse visits was the same in both groups, while the number of telephone contacts was 38% higher in the tailored group (p = 0.02).

CONCLUSION

A tailored, nurse-led cardiac rehabilitation programme can improve risk factor management in post-AMI patients.

Blood lactate is a predictor of short-term mortality in patients with myocardial infarction complicated by heart failure but without cardiogenic shock

Background

Mortality in patients with acute myocardial infarction (AMI) has improved substantially with modern therapy including percutaneous coronary interventions (PCI) but remains high in certain subgroups such as patients presenting with overt cardiogenic shock. However, the risk for AMI in patients presenting acutely with signs of heart failure but without cardiogenic shock is less well described. We aimed to identify risk factors for mortality in AMI patients with heart failure without overt cardiogenic shock.

Methods

Using data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR), we identified patients with operator-registered heart failure (Killip class II-IV), and evaluated predictors of mortality based on clinical factors from review of patient records.

Results

A total of 1260 unique patients with acute myocardial infarction underwent PCI in 2014, of which 77 patients (7%) showed signs of heart failure (Killip II-IV) Overall 30-day mortality in patients with Killip class II-IV was 20% (N = 15). In patients classified Killip IV (1%), 30-day mortality was 50% (N = 6). In patients presenting with mild to moderate heart failure (Killlip class II-III), 30-day mortality was 14% (N = 9). In patients with Killip class II-III, lactate ≥2.5 mmol/L was associated with 30-day mortality, whereas systolic blood pressure < 90 mmHg, age, sex and BMI were not. In patients with lactate < 2.5 mmol/L 30-day mortality was 5% (N = 2) whereas mortality was 28% (N = 7) with lactate ≥2.5 mmol/L. This cut-off provided discriminative information on 30-day mortality (area under ROC curve 0.74).

Conclusions

In patients with AMI and signs of mild to moderate heart failure, lactate ≥2.5 mmol/L provides additional prognostic information. Interventions to reduce risk may be targeted to these patients.

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 .).

Cangrelor in combination with ticagrelor provides consistent and potent P2Y12-inhibition during and after primary percutaneous coronary intervention in real-world patients with ST-segment-elevation myocardial infarction

Patients pretreated with ticagrelor with less than 1 hour from percutaneous coronary intervention (PCI) or receiving ticagrelor in cath lab were prospectively included and received cangrelor. Cangrelor was infused for 2 hours and platelet function was assessed as P2Y12 reactivity units (PRU) with the VerifyNow P2Y12 function assay before start of infusion, 15 min after the start of infusion, and 30 min after the end of infusion. A total of n = 32 patients with an average age of 68 (±13) years with n = 22 (69%) males were included. The level of P2Y12 inhibition before cangrelor infusion was started was 249 PRU (IQR 221-271). After 15 min of cangrelor infusion the P2Y12 reactivity was markedly decreased to 71 PRU (IQR 52-104, p < 0.001). At 30 min after end of infusion PRU remained within the therapeutic range, 89 PRU (IQR 50-178; p < 0.001 for comparison with preinfusion) with only n = 4 (12.5%) patients with PRU >225. Results were consistent between patients receiving ticagrelor prehospital or in the cath lab and no statistical differences in PRU were noted between the two groups in any of the three measurements. In conclusion, cangrelor in combination with ticagrelor results in consistent and strong P2Y12 inhibition during and after infusion and cangrelor may bridge the gap until oral P2Y12 inhibitors achieve effect in real-world STEMI patients undergoing primary PCI.

Bivalirudin versus heparin in non-ST and ST-segment elevation myocardial infarction-a registry-based randomized clinical trial in the SWEDEHEART registry (the VALIDATE-SWEDEHEART trial)

BACKGROUND

The optimal anticoagulant for patients with acute coronary syndrome treated with percutaneous coronary intervention (PCI) has not been validated in current practice of radial approach and pretreatment with potent P2Y12 inhibitors. Several studies have indicated increased bleeding rate and, in some instances, even increased mortality by the routine use of heparin and glycoprotein IIb/IIIa inhibitors compared to bivalirudin. Direct comparison of bivalirudin versus heparin alone has yielded contradictory results depending on study designs.

METHODS/DESIGN

The VALIDATE-SWEDEHEART trial is a multicenter, prospective, randomized, registry-based, controlled, and open-label clinical trial in patients with ST-segment elevation myocardial infarction (STEMI) or non-STEMI undergoing PCI pretreated with ticagrelor, prasugrel, or cangrelor. We hypothesize that bivalirudin is superior to heparin alone in reducing death, myocardial infarction, and major bleeding events at 180 days (primary end point). The trial will enroll 3,000 patients with STEMI and 3,000 patients with non-STEMI undergoing PCI. The trial will use a hybrid registry-based randomized clinical trial design where inclusion, randomization, and baseline data collection are performed using The Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies registry. The primary composite end point (death, myocardial infarction, or major bleeding events at 180 days) will be identified through active screening after 7 and 180 days and adjudicated by a blinded central end point committee. Secondary end points and long-term outcomes will be recorded from national registries.

CONCLUSION

The VALIDATE-SWEDEHEART trial is founded on a nationwide clinical registry and uses a hybrid registry-based randomized clinical trial (RRCT) design methodology to evaluate efficacy and safety of bivalirudin as compared to heparin alone for acute coronary syndrome, in a large population receiving contemporary recommended therapies including predominantly radial invasive approach and pretreatment with potent P2Y12 inhibitors.

A pharmacodynamic comparison of 5 anti-platelet protocols in patients with ST-elevation myocardial infarction undergoing primary PCI

Background

Despite advances in anti-platelet treatments, there still exists an early increase in both ischemic as well as bleeding events following primary PCI in patients with ST-elevation myocardial infarction (STEMI). Platelet inhibition data of different anti-platelet treatments in the acute phase of a myocardial infarction might offer some insight into these problems. The aim of this study was to evaluate the pharmacodynamic profile of 5 different anti-platelet treatments in the acute phase of STEMI in patients undergoing primary PCI.

Methods

A total of 223 STEMI patients undergoing primary PCI were prospectively included. Patients received either pre-hospital clopidogrel only, pre-hospital clopidogrel followed by prasugrel switch in the cath lab, prasugrel treatment only, pre-hospital clopidogrel followed by ticagrelor switch in the cath lab or pre-hospital ticagrelor only. Platelet reactivity was measured serially using vasodilator-stimulated phosphoprotein (VASP).

Results

Patients receiving pre-hospital clopidogrel followed by prasugrel switch showed similar platelet inhibition data as patients receiving prasugrel only, with more than 90% being good responders the day after PCI. Average time from prasugrel administration to a VASP value of <50% was 1.5 hours. In patients receiving pre-hospital ticagrelor, 50% were good responders at completion of PCI and average time to a VASP-value of <50% was 2.3 hours. Only 32% of patients receiving clopidogrel only were responders the day after PCI.

Conclusions

Switching from an upstream bolus dose of clopidogrel to prasugrel at the time of PCI, appeared as a safe and feasible option with no tendency for overshoot or attenuation of platelet inhibition. Pre-hospital administration of ticagrelor was associated with a 50% good responder rate at completion of PCI.

Delay from first medical contact to primary PCI and all-cause mortality: a nationwide study of patients with ST-elevation myocardial infarction

Background

Early reperfusion in the setting of an ST‐elevation myocardial infarction (STEMI) is of utmost importance. However, the effects of early versus late reperfusion in this patient group undergoing primary percutaneous coronary intervention (PCI) have so far been inconsistent in previous studies. The purpose of this study was to evaluate in a nationwide cohort the effects of delay from first medical contact to PCI (first medical contact [FMC]‐to‐PCI) and secondarily delay from symptom‐to‐PCI on clinical outcomes.

Methods and Results

Using the national Swedish Coronary Angiography and Angioplasty Register (SCAAR) registry, STEMI patients undergoing primary PCI between the years 2003 and 2008 were screened for. A total of 13 790 patients were included in the FMC‐to‐PCI analysis and 11 489 patients were included in the symptom‐to‐PCI analyses. Unadjusted as well as multivariable analyses showed an overall significant association between increasing FMC‐to‐PCI delay and 1‐year mortality. A statistically significant increase in mortality was noted at FMC‐to‐PCI delays exceeding 1 hour in an incremental fashion. FMC‐to‐PCI delays in excess of 1 hour were also significantly associated with an increase in severe left ventricular dysfunction at discharge. An overall significant association between increasing symptom‐to‐PCI delays and 1‐year mortality was noted. However, when stratified into time delay cohorts, no symptom‐to‐PCI delay except for the highest time delay showed a statistically significant association with increased mortality.

Conclusions

Delays in FMC‐to‐PCI were strongly associated with increased mortality already at delays of more than 1 hour, possibly through an increase in severe heart failure. A goal of FMC‐to‐PCI of less than 1 hour might save patient lives.

Long-term safety and efficacy of drug-eluting and bare metal stents in saphenous vein grafts

BACKGROUND

Long-term safety and efficacy data of drug-eluting stents (DESs) in saphenous vein grafts (SVGs) are lacking. This study sought to compare the clinical outcomes of DES versus bare metal stents (BMS) in SVGs.

METHODS

We studied all stent implantations in SVGs in Sweden during 74 months between 2005 and 2011 registered in the Swedish Coronary Angiography and Angioplasty Registry. We evaluated outcome in patients who received DES compared with those who received BMS after adjustments for differences in clinical, vessel, and lesion characteristics.

RESULTS

Mean follow-up time was 3 years and 4 months. A total of 4,576 stents, implanted at 3,063 procedures, were included in the analysis of which 2,499 stents (54.6 %) were BMS and 2,077 (45.4%) were DES. The outcome analysis was based on 190 stent thromboses, 898 restenoses, and 523 deaths. The incidence of stent thrombosis did not differ between groups. When adjusted for baseline characteristics, including a propensity score for receiving DES, the incidence of restenosis was significantly lower with DES as compared with BMS (risk ratio 0.83, 95% CI 0.70-0.97, P = .019). There was a difference in mortality in the crude analysis between DES and BMS, and after multivariable adjustment, this difference remained statistically significant (risk ratio 0.80, CI 0.65-0.99, P = .038).

CONCLUSIONS

The use of DES compared with BMS in SVGs was associated with a significantly lower adjusted incidence of restenosis and death in this large, national, all-encompassing propensity adjusted observational study.

Safety and efficacy of drug-eluting vs. bare metal stents in patients with diabetes mellitus: long-term follow-up in the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)

AIMS

Patients with diabetes mellitus have more extensive coronary artery disease, more disease progression, and restenosis. The use of drug-eluting stents (DES) in these patients is widespread, despite uncertain long-term safety and efficacy.

METHODS AND RESULTS

All consecutive patients with diabetes mellitus in Sweden who underwent percutaneous coronary intervention were entered into the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) during 2003-06 with complete follow-up for 1-4 years (median 2.5). Patients who received at least one DES (n = 4754) were compared with those who received only bare metal stents (BMS) (n = 4956) at the index procedure. Combined outcome of death or myocardial infarction (MI) showed no difference for DES vs. BMS, relative risk (RR), 0.91 [95% confidence interval (CI), 0.77-1.06]. Myocardial infarction was significantly less common with DES in patients who received only one stent RR, 0.80 (95% CI, 0.66-0.96). The restenosis rate was 50% lower in DES-treated patients RR, 0.50 (95% CI, 0.35-0.70) and was associated with a higher adjusted RR of MI, RR, 5.03 (95% CI, 4.25-5.97). DES was associated with reduced restenosis rates in all subgroups of diabetic patients with the greatest benefit in stent diameters <3 mm or stent length >20 mm. The number of lesions treated with DES to prevent one restenosis ranged from 11 to 47 in various subgroups.

CONCLUSION

This real-life registry study shows that restenosis was halved by DES in diabetic patients with stable or unstable coronary disease, with similar risk of death or MI up to 4 years compared with BMS.

Stent thrombosis in Sweden: a report from the Swedish Coronary Angiography and Angioplasty Registry

BACKGROUND

The objective was to evaluate the role of risk factors and stent type for stent thrombosis (ST) using a large real world registry.

METHODS AND RESULTS

We evaluated all consecutive coronary stent implantations in Sweden from May 1, 2005, to June 30, 2007. All cases of ST, documented in the Swedish coronary angiography and angioplasty registry until September 21, 2008, were analyzed. ST was registered in 882 of 73 798 stents. Acute coronary syndromes, insulin-treated diabetes mellitus, smoking, previous coronary intervention, warfarin treatment, small stent diameter, and stenting in restenotic, complex, or bypass graft lesions had the strongest association with ST in the multivariable statistical model. There were considerable differences in the frequency of ST between different stent brands. The overall risk of ST was lower in drug-eluting stents compared with bare metal stents (adjusted risk ratio, 0.79; 99% CI, 0.63 to 0.99). However, from 6 months after stent implantation and onward, the risk for ST was higher in drug-eluting stents compared with bare metal stents (adjusted risk ratio, 2.02; 99% CI, 1.30 to 3.14).

CONCLUSIONS

ST is a multifactor disease, and the incidence varies considerably between patients based on clinical, vessel, and stent characteristics. For drug-eluting stents compared with bare metal stents, the risk pattern was biphasic; initially, bare metal stents demonstrated a higher risk of ST; whereas after the first months, ST risk was higher with drug-eluting stents. Our findings highlight the need for prospective randomized studies with head-to-head comparisons between different stents.

Long-term safety and efficacy of drug-eluting versus bare-metal stents in Sweden

BACKGROUND

The long-term safety and efficacy of drug-eluting coronary stents have been questioned.

METHODS

We evaluated 47,967 patients in Sweden who received a coronary stent and were entered into the Swedish Coronary Angiography and Angioplasty Registry between 2003 and 2006 and for whom complete follow-up data were available for 1 to 5 years (mean, 2.7). In the primary analysis, we compared patients who received one drug-eluting coronary stent (10,294 patients) with those who received one bare-metal stent (18,659), after adjustment for differences in clinical characteristics of the patients and characteristics of the vessels and lesions.

RESULTS

Analyses of outcome were based on 2380 deaths and 3198 myocardial infarctions. There was no overall difference between the group that received drug-eluting stents and the group that received bare-metal stents in the combined end point of death or myocardial infarction (relative risk with drug-eluting stents, 0.96; 95% confidence interval [CI], 0.89 to 1.03) or the individual end points of death (relative risk, 0.94; 95% CI, 0.85 to 1.05) and myocardial infarction (relative risk, 0.97; 95% CI, 0.88 to 1.06), and there was no significant difference in outcome among subgroups stratified according to the indication for stent implantation. Patients who received drug-eluting stents in 2003 had a significantly higher rate of late events than patients who received bare-metal stents in the same year, but we did not observe any difference in outcome among patients treated in later years. The average rate of restenosis during the first year was 3.0 events per 100 patient-years with drug-eluting stents versus 4.7 with bare-metal stents (adjusted relative risk, 0.43; 95% CI, 0.36 to 0.52); 39 patients would need to be treated with drug-eluting stents to prevent one case of restenosis. Among high-risk patients, the adjusted risk of restenosis was 74% lower with drug-eluting stents than with bare-metal stents, and only 10 lesions would need to be treated to prevent one case of restenosis.

CONCLUSIONS

As compared with bare-metal stents, drug-eluting stents are associated with a similar long-term incidence of death or myocardial infarction and provide a clinically important decrease in the rate of restenosis among high-risk patients.

Successful resuscitation with mechanical CPR, therapeutic hypothermia and coronary intervention during manual CPR after out-of-hospital cardiac arrest

A 62-year-old man suffered out-of-hospital cardiac arrest and was treated with mechanical compression-decompression during transport to the hospital. In the emergency department, 28 min after cardiac arrest, spontaneous circulation returned briefly but the patient rapidly became asystolic and mechanical compression-decompression was again applied. After further resuscitation a spontaneous circulation returned and the patient was transferred, deeply comatose, to the coronary intervention laboratory while therapeutic hypothermia was induced. In the laboratory the heart arrested again and coronary angiography was performed during manual CPR revealing a left main stem occlusion. After successful reperfusion of the heart the patient was transferred to the intensive care unit with an intra-aortic balloon pump. The patient was treated with hypothermia for 24 h and awoke without neurological sequelae after a sustained intensive care period of 13 days. The present case is an example of how modern resuscitation principles implementing new clinical and experimental findings may strengthen the chain of survival during resuscitation.

Melagatran attenuates fibrin and platelet deposition in a porcine coronary artery over-stretch injury model

Melagatran is the active form of the oral direct thrombin inhibitor, ximelagatran. The purpose of this study was to compare the effects of different doses of melagatran with heparin or placebo on platelet deposition and relative fibrin content after coronary angioplasty in pigs. After 125I-labelled fibrinogen and autologous 111Indium-labelled platelets had been infused a balloon injury was performed in the left anterior descending and the right coronary arteries. Pigs were randomized to receive either heparin 200 IU/kg bolus plus 20 IU/kg per h infusion (n = 7); melagatran 1 mg/kg bolus plus 0.33 mg/kg per h infusion (n = 7); melagatran bolus 0.5 mg/kg plus 0.17 mg/kg per h infusion (n = 7); melagatran 0.15 mg/kg bolus plus 0.05 mg/kg per h infusion (n = 6) or saline (n = 4). Seventy-five minutes after the angioplasty, the pigs were euthanized and the injured vessel segments were measured in a gamma counter. Compared with placebo, platelet deposition and relative fibrin content were reduced after both heparin and melagatran, in the latter case with a dose-response relationship. Melagatran reduced platelet deposition and relative thrombus size in a dose-dependent manner when compared with placebo after coronary angioplasty in pigs. No statistically significant difference between melagatran and heparin was found.

There is no effect on remodeling of vascular wall 4 weeks after local delivery of antithrombin in a porcine model of coronary overstretching

BACKGROUND

Antithrombin III is an effective endogenous inhibitor of thrombin with antiproliferative and anti-inflammatory capabilities. Systematic administration of direct thrombin inhibitors as well as of antithrombin has proven effective at reducing formation of neointima after injury to vessel wall in various animal models. Local delivery of antithrombin attenuates deposition of platelets after balloon injury to porcine coronary vessels.

OBJECTIVE

To test our hypothesis that local delivery of antithrombin affects remodeling of vessel wall after balloon injury to the left anterior descending artery (LAD) in pigs.

METHODS

With a balloon:vessel diameter ratio of 1.5 deep vessel-wall injury was performed with conventional balloon angioplasty in the LAD in 16 pigs. After balloon injury the pigs were administered locally two doses of 2.5 ml antithrombin (250 U) or, as a control, two doses of 2.5 ml albumin (10 mg). All pigs were administered 200 U/kg bodyweight heparin before catheterization. The animals were then kept in stalls and fed normal grain. After approximately 4 weeks the animals were killed and lesions were assessed by computer-assisted image analysis. The areas of each vessel-wall layer and the percentage area stenosis were calculated. As a measure of injury, the length of rupture of the lamina elastica interna was measured.

RESULTS

The injury was found to be equally profound in pigs of these groups. There was no significant difference between the groups concerning the areas of vessel-wall layers. The percentage area stenosis was similar for pigs in these two groups (36.5 +/- 14.9% for pigs in the antithrombin group versus 35.4 +/- 16.2% for pigs in the control group, NS).

CONCLUSIONS

Local delivery of 250 U antithrombin to the LAD in pigs did not affect remodeling of the vessel wall 4 weeks after balloon injury.

Local delivery of antithrombin inhibits platelet deposition after balloon injury in a porcine coronary model

BACKGROUND

Thrombin activation and initiation of the coagulation process can lead to thrombotic complications after coronary angioplasty. A therapeutic approach may be effectively to inhibit thrombin activity at the site of the vessel wall injury.

OBJECTIVE

The aim of the present study was to investigate the short-term effects of local delivery of antithrombin on coronary vessel wall injury in pigs.

METHODS

A coronary balloon angioplasty was performed in the left anterior descending artery. Twenty-four hours before the procedure, platelets were marked with Indium 111 and infused into the pig. Before catheterisation 100 U/kg of heparin was administered. Eight pigs received 250 U (5 ml) of antithrombin and, as a control, eight received 10 mg of albumin (5 ml) delivered using a local drug delivery balloon catheter. Microscopic preparation of the injured part of the vessel was performed, and the amount of radioactivity was measured, giving the number of platelets per cm2. Plasma antithrombin level was measured before and after local delivery. The amount of antithrombin in the vessel wall was measured using a semi-quantitative method involving anti-antithrombin antibodies.

RESULTS

The number of platelets per cm2 was significantly lower in the antithrombin group (mean 2.3 x 10(6)) than in the control group (6.3 x 10(6), P= 0.02 ). No macroscopic thrombus was detected in the antithrombin group, whereas three out of eight pigs in the control group had visible thrombus formation (NS). There was an increase in the plasma concentration of antithrombin after local delivery. In the antithrombin group, antithrombin was detected in the intima, the lumen part of the media and in the vasa vasorum.

CONCLUSION

Antithrombin can be administered and deposited locally in the coronary vessel wall thereby reducing platelet deposition after balloon injury.