Angioplasty strategies in ST-segment-elevation myocardial infarction: part I: primary percutaneous coronary intervention

Rates and Patterns of First-Time Admissions for Acute Coronary Syndromes across Western Australia Using Linked Administrative Health Data 2007-2015

Acute coronary syndrome (ACS) is globally recognised as a significant health burden, for which the reduction in total ischemic times by way of the most suitable reperfusion strategy has been the focus of national and international initiatives. In a setting such as Western Australia, characterised by 79% of the population dwelling in the greater capital region, transfers to hospitals capable of percutaneous coronary intervention (PCI) is often a necessary but time-consuming reality for outer-metropolitan and rural patients. Methods: Hospital separations, emergency department admissions and death registration data between 1 January 2007 and 31 December 2015 were linked by the Western Australian Data Linkage Unit, identifying patients with a confirmed first-time diagnosis of ACS, who were either a direct admission or experienced an inter-hospital transfer. Results: Although the presentation rates of ACS remained stable over the nine years evaluated, the rates of first-time admissions for ACS were more than double in the rural residential cohort, including higher rates of ST-segment elevation myocardial infarction, the most time-critical manifestation of ACS. Consequently, rural patients were more likely to undergo an inter-hospital transfer. However, 42% of metropolitan admissions for a first-time ACS also experienced a transfer. Conclusion: While the time burden of inter-hospital transfers for rural patients is a reality in health care systems where it is not feasible to have advanced facilities and workforce skills outside of large population centres, there is a concerning trend of inter-hospital transfers within the metropolitan region highlighting the need for further initiatives to streamline pre-hospital triage to ensure patients with symptoms indicative of ACS present to PCI-equipped hospitals.

Cardiac remodeling after large ST-elevation myocardial infarction in the current therapeutic era

BACKGROUND

The evolution and clinical impact of cardiac remodeling after large ST-elevation myocardial infarction (STEMI) is not well delineated in the current therapeutic era.

METHODS

The PRESERVATION I trial longitudinally assessed cardiac structure and function in STEMI patients receiving primary percutaneous coronary intervention (PCI). Echocardiograms were performed immediately post-PCI and at 1, 3, 6 and 12 months after STEMI. The extent of cardiac remodeling was assessed in patients with ejection fraction (EF) ≤ 40% after PCI. Patients were stratified by the presence or absence of reverse remodeling, defined as an increase in end-diastolic volume (EDV) of ≤10 mL or decrease in EDV at 1 month, and evaluated for an association with adverse events at 1 year.

RESULTS

Of the 303 patients with large STEMI enrolled in PRESERVATION I, 225 (74%) had at least moderately reduced systolic function (mean EF 32 ± 5%) immediately after primary PCI. In the following year, there were significant increases in EF and LV volumes, with the greatest magnitude of change occurring in the first month. At 1 month, 104 patients (46%) demonstrated reverse remodeling, which was associated with a significantly lower rate of death, recurrent myocardial infarction and repeat cardiovascular hospitalization at 1 year (HR 0.44; 95% CI: 0.19-0.99).

CONCLUSION

Reduced EF after large STEMI and primary PCI is common in the current therapeutic era. The first month following primary reperfusion is a critical period during which the greatest degree of cardiac remodeling occurs. Patients demonstrating early reverse remodeling have a significantly lower rate of adverse events in the year after STEMI.

Identifying patients with refusal of percutaneous coronary intervention for acute myocardial infarction: a classification and regression tree analysis

The purpose of the present study is to develop and validate a prediction tool to identify patients who refuse to receive percutaneous coronary intervention (PCI) rapidly. We developed a risk stratification model using the derivation cohort of 288 patients with ST segment elevation myocardial infarction (STEMI) in our hospital and validated it in a prospective cohort of 115 patients. There were 52 (18.1%) patients and 18 (15.7%) patients who refused PCI among derivation and validation cohort, respectively. A classification and regression tree (CART) analysis and multivariate logistic regression were used for statistical analysis. The decision-making factors for refusal of PCI were also investigated. The CART analysis and logistic regression both showed that self-rated mild symptom was the most significant predictor of not choosing PCI. The model generated three risk groups. The high-risk group included: self-rated mild symptoms; self-rated severe symptom, glomerular filtration rate < 60 ml/min/1.73m². The intermediate-risk group included: self-rated severe symptom, glomerular filtration rate ≥ 60 ml/min/1.73m² and age ≥ 75 years. The low-risk group included: self-rated severe symptom, glomerular filtration rate ≥ 60 ml/min/1.73m² and age < 75 years. The prevalence for refusal of PCI of the three groups were 45%-44%, 18% and 4%, respectively. The sensitivity was 88% and the negative predictive value was 96%. And similar results were obtained when this prediction tool was applied prospectively to the validation cohort. Patients at low and high risk can be easily identified for refusal of PCI by the prediction tool using common clinical data. This practical model might provide useful information for rapid recognition and early response for this kind of crowd.

Intracoronary Glycoprotein IIb/IIIa Inhibitors Improve Short-Term Mortality and Reinfarction in East Asian Patients with ST-Segment Elevation Myocardial Infarction after Thrombus Aspiration: A Meta-Analysis

Objective

Intracoronary (IC) glycoprotein IIb/IIIa inhibitors (GPIs) after thrombus aspiration (TA) for patients with ST-segment elevation myocardial infarction (STEMI), as compared with percutaneous coronary interventions (PCI) alone, is still on debate. To address this issue, we performed a meta-analysis of results from prospective or randomized controlled trials on the topic.

Methods

We searched electronic and printed sources (up to June 20, 2016) according to the selection criteria. Data were abstraction and meta-analysis was performed using RevMan 5.3 software.

Results

The cohorts involved 14 articles describing 1,918 participants were included. The incidence of the short-term major adverse cardiac events (MACE) was significantly reduced with intracoronary GPIs after TA (odds ratio [OR]: 0.29; 95% confidence interval [CI]: 0.13 to 0.65, p=0.003). Benefits were noted for short-term mortality (OR: 0.31; 95% CI: 0.17 to 0.57, p=0.0002) and reinfarction (OR: 0.28; 95% CI: 0.10 to 0.78, p=0.01) in subjects who received intracoronary GPIs after TA. Moreover, the Thrombolysis in Myocardial Infarction (TIMI) trial grade 3 postprocedure (OR: 2.29; 95% CI: 1.72 to 3.04, P<0.00001) and complete ST-segment resolution (STR) rate (OR: 2.68; 95% CI: 1.85 to 3.87, P<0.00001) were both improved with intracoronary GPIs after TA. As a result, left ventricular ejection fraction (LVEF) at short-term follow-up showed a significant difference (OR: 7.33; 95% CI: 5.60 to 9.06, p<0.0001) in favor of the TA and intracoronary GPIs administration.

Conclusions

Our study demonstrates that intracoronary GPIs may have a synergistic effect with thrombus aspiration on short-term mortality, reinfarction, and cardiac functional recovery.

Inhibition of activated factor X by rivaroxaban attenuates neointima formation after wire-mediated vascular injury

Accumulating evidence suggests that activated factor X (FXa), a key coagulation factor, plays an important role in the development of vascular inflammation through activation of many cell types. Here, we investigated whether pharmacological blockade of FXa attenuates neointima formation after wire-mediated vascular injury. Transluminal femoral artery injury was induced in C57BL/6 mice by inserting a straight wire. Rivaroxaban (5mg/kg/day), a direct FXa inhibitor, was administered from one week before surgery until killed. At four weeks after surgery, rivaroxaban significantly attenuated neointima formation in the injured arteries compared with control (P<0.01). Plasma lipid levels and blood pressure were similar between the rivaroxaban-treated group and non-treated group. Quantitative RT-PCR analyses demonstrated that rivaroxaban reduced the expression of inflammatory molecules (e.g., IL-1β and TNF-α) in injured arteries at seven days after surgery (P<0.05, respectively). In vitro experiments using mouse peritoneal macrophages demonstrated that FXa increased the expression of inflammatory molecules (e.g., IL-1β and TNF-α), which was blocked in the presence of rivaroxaban (P<0.05). Also, in vitro experiments using rat vascular smooth muscle cells (VSMC) demonstrated that FXa promoted both proliferation and migration of this cell type (P<0.05), which were blocked in the presence of rivaroxaban. Inhibition of FXa by rivaroxaban attenuates neointima formation after wire-mediated vascular injury through inhibition of inflammatory activation of macrophages and VSMC.

Percutaneous cardiac support during myocardial infarction drastically reduces mortality: perspectives from a swine model

BACKGROUND/AIMS

Acute myocardial infarction (AMI) with cardiogenic shock (CS) remains the leading cause of in-hospital death in acute coronary syndromes. In the AMI-CS pig model we tested the efficacy of temporary percutaneous cardiorespiratory assist device (PCRA) in rescuing the failing heart and reducing early mortality.

METHODS

In open-chest pigs we induced AMI by proximal left anterior descending coronary artery (LAD) ligation. Eight animals without PCRA (C group) were compared with 12 animals otherwise treated with PCRA (T group), starting approximately at 60 minutes post-occlusion and lasting 120-180 minutes. In 3 animals of the T group, regional myocardial oxygen content was also imaged by two-dimensional near infrared spectroscopy (2D-NIRS) with and without PCRA, before and after LAD reperfusion.

RESULTS

All animals without PCRA died despite unrelenting resuscitation maneuvers (120 minutes average survival time). Conversely, animals treated with PCRA showed a reduction in life-threatening arrhythmia and maintenance of aortic pressure, allowing interruption of PCRA in all cases early in the experiments, with sound hemodynamics at the end of the observation period. During LAD occlusion, NIRS showed severe de-oxygenation of the LAD territory that improved with PCRA. After PCRA suspension and LAD reperfusion, the residual de-oxygenated area proved to be smaller than the initial risk area.

CONCLUSIONS

In AMI, PCRA initiated during advanced CS drastically reduced early mortality from 100% to 0% in a 4-5 hour observation period. PCRA promoted oxygenation of the ischemic area during LAD occlusion. Results support the use of PCRA as first line of treatment in AMI-CS, improving myocardial rescue and short-term survival.

Non-infarct related artery revascularization in ST-segment elevation myocardial infarction patients with multivessel disease

PURPOSE OF REVIEW

Multivessel disease (MVD) is common in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) and is associated with significant risk of future cardiovascular (CV) events including short and longer-term mortality. In this review, we examine the pathophysiologic construct contributing to adverse prognosis of MVD in STEMI, relevant available evidence that currently guides the management of the noninfarct-related artery (IRA) stenosis and define the remaining knowledge gaps for future studies.

RECENT FINDINGS

Results of recent small sized randomized trials, when pooled, suggest improvement in CV outcomes including CV mortality and repeat revascularization with revascularization of the non-IRA stenosis compared with medical management alone. In addition, there does not appear to be an increase in bleeding, contrast-induced nephropathy or stroke, as suggested by earlier observational data.

SUMMARY

These recent data have led to a Class IIb recommendation in the American College of Cardiology/American Heart Association guidelines stating that non-IRA revascularization may be considered in selected patients with STEMI and MVD who are hemodynamically stable, either at the time of primary PCI or as a planned staged procedure. The ongoing COMPLETE and CULPRIT-SHOCK studies will provide additional data to further inform the role of non-IRA revascularization and its timing in the management of these patients.

Direct Admission Versus Interhospital Transfer for Primary Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction

OBJECTIVES

This study sought to assess the influence of direct admission versus transfer via regional hospital to a percutaneous coronary intervention (PCI) center on time delays and 12-month mortality in ST-segment elevation myocardial infarction (STEMI) patients from a real-life perspective.

BACKGROUND

Reduction of delays to reperfusion is crucial in a STEMI system of care. However, it is still debated whether direct admission to a PCI center is superior to interhospital transfer in terms of long-term prognosis. The authors hypothesized that compared with interhospital transfer, direct admission shortens the total ischemic time, limits the loss of left ventricular systolic function, and finally, reduces 12-month mortality.

METHODS

Prospective nationwide registry data of STEMI patients admitted to PCI centers within 12 h of symptom onset and treated with PCI between 2006 and 2013 were analyzed. Patients admitted directly were compared with patients transferred to a PCI center via a regional non-PCI-capable facility in terms of time delays, left ventricular ejection fraction (LVEF), and 12-month mortality. Data were adjusted using propensity-matched and multivariate Cox analyses.

RESULTS

Of the 70,093 patients eligible for analysis, 39,144 (56%) were admitted directly to a PCI center. Direct admission was associated with a shorter median symptoms-to-admission time (by 44 min; p < 0.001) and total ischemic time (228 vs. 270 min; p < 0.001), higher LVEF (47.5% vs. 46.3%; p < 0.001), and lower propensity-matched 12-month mortality (9.6% vs. 10.4%; p < 0.001). In propensity-matched multivariate Cox analysis, direct admission (hazard ratio [HR]: 1.06, 95% confidence interval [CI]: 1.01 to 1.11) and shorter symptoms-to-admission time (HR: 1.03; 95% CI: 1.01 to 1.06) were significant predictors of lower 12-month mortality.

CONCLUSIONS

In a large, community-based cohort of patients with STEMI treated by PCI, direct admission to a primary PCI center was associated with lower 12-month mortality and should be preferred to transfer via a regional non-PCI-capable facility.

Health Care Exceptionalism? Performance and Allocation in the US Health Care Sector

The conventional wisdom for the healthcare sector is that idiosyncratic features leave little scope for market forces to allocate consumers to higher performance producers. However, we find robust evidence - across several different conditions and performance measures - that higher quality hospitals have higher market shares and grow more over time. The relationship between performance and allocation is stronger among patients who have greater scope for hospital choice, suggesting that patient demand plays an important role in allocation. Our findings suggest that healthcare may have more in common with "traditional" sectors subject to market forces than often assumed.

A prospective, observational, multicentre study comparing tenecteplase facilitated PCI versus primary PCI in Indian patients with STEMI (STEPP-AMI)

Objective

To compare the efficacy of pharmacoinvasive strategy versus primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). Primary PCI is the preferred treatment for STEMI, but it is not a feasible option for many. A pharmacoinvasive strategy might be a practical solution in the Indian context, although few empirical data exist to guide this approach.

Methods

This is a prospective, observational, multicentre pilot study. Two hundred consecutive patients with STEMI aged 18–75 years, presenting within 12 h of onset of symptoms and requiring a reperfusion strategy, were studied from five primary PCI capable centres in South India. Patients who opted for pharmacoinvasive strategy (n=45) formed group A. Group B consisted of patients treated with primary PCI (n=155). One patient was lost to follow-up at 1 year. The primary end point was a composite of death, cardiogenic shock, reinfarction, repeat revascularisation of a culprit artery and congestive heart failure at 30 days.

Results

The primary end point occurred in 11.1% in group A and in 3.9% in group B, p=0.07 (RR=2.87; 95% CI 0.92 to 8.97). The infarct-related artery patency at angiogram was 82.2% in group A and 22.6% in group B (p<0.001). PCI was performed in 73.3% in group A versus 100% in group B (p<0.001), and a thrombus was present in 26.7% in group A versus 63.2% in group B (p<0.001). Failed fibrinolysis occurred in 12.1% in group A. There was no difference in bleeding risk, 2.2% in group A versus 0.6% in group B, (p=0.4).

Conclusions

This pilot study shows that a pharmacoinvasive strategy can be implemented in patients not selected for primary PCI in India and hints at the possibility of similar outcomes. Larger studies are required to confirm these findings.

Trial registration number

Trial is registered with Clinical trial registry of India, CTRI number: REF/2011/07/002556.

Reperfusion strategies in acute coronary syndromes

The appropriate timing of angiography to facilitate revascularization is essential to optimize outcomes in patents with ST-segment-elevation myocardial infarction and non-ST-segment-elevation acute coronary syndromes. Timely reperfusion of the infarct-related coronary artery in ST-segment-elevation myocardial infarction both with fibrinolysis or percutaneous coronary intervention minimizes myocardial damage, reduces infarct size, and decreases morbidity and mortality. Primary percutaneous coronary intervention is the preferred reperfusion method if it can be performed in a timely manner. Strategies to reduce health system-related delays in reperfusion include regionalization of ST-segment-elevation myocardial infarction care, performing prehospital ECGs, prehospital activation of the catheterization laboratory, bypassing geographically closer nonpercutaneous coronary intervention-capable hospitals, bypassing the percutaneous coronary intervention-capable hospital emergency department, and early and consistent availability of the catheterization laboratory team. With implementation of such strategies, there has been significant improvement in process measures, including door-to-balloon time. However, despite reductions in door-to-balloon times, there has been little change during the past several years in in-hospital mortality, suggesting additional factors including patient-related delays, optimization of tissue-level perfusion, and cardioprotection must be addressed to improve patient outcomes further. Early angiography followed by revascularization when appropriate also reduces rates of death, MI, and recurrent ischemia in patients with non-ST-segment-elevation acute coronary syndromes, with the greatest benefits realized in the highest risk patients. Among patients with non-ST-segment-elevation acute coronary syndromes with multivessel disease, choice of revascularization modality should be made as in stable coronary artery disease, with a goal of complete ischemic revascularization.

Myocardial ischemia is a key factor in the management of stable coronary artery disease

Previous studies demonstrated that coronary revascularization, especially percutaneous coronary intervention (PCI), does not significantly decrease the incidence of cardiac death or myocardial infarction in patients with stable coronary artery disease. Many studies using myocardial perfusion imaging (MPI) showed that, for patients with moderate to severe ischemia, revascularization is the preferred therapy for survival benefit, whereas for patients with no to mild ischemia, medical therapy is the main choice, and revascularization is associated with increased mortality. There is some evidence that revascularization in patients with no or mild ischemia is likely to result in worsened ischemia, which is associated with increased mortality. Studies using fractional flow reserve (FFR) demonstrate that ischemia-guided PCI is superior to angiography-guided PCI, and the presence of ischemia is the key to decision-making for PCI. Complementary use of noninvasive MPI and invasive FFR would be important to compensate for each method's limitations. Recent studies of appropriateness criteria showed that, although PCI in the acute setting and coronary bypass surgery are properly performed in most patients, PCI in the non-acute setting is often inappropriate, and stress testing to identify myocardial ischemia is performed in less than half of patients. Also, some studies suggested that revascularization in an inappropriate setting is not associated with improved prognosis. Taken together, the presence and the extent of myocardial ischemia is a key factor in the management of patients with stable coronary artery disease, and coronary revascularization in the absence of myocardial ischemia is associated with worsened prognosis.

Prognostic significance of postprocedural sustained ventricular tachycardia or fibrillation in patients undergoing primary percutaneous coronary intervention (from the HORIZONS-AMI Trial)

The prognostic significance of postprocedure sustained ventricular tachycardia or ventricular fibrillation (VT/VF) in patients undergoing primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI) has rarely been studied, although a previous study has suggested that its occurrence portends decreased survival. We examined outcomes from the prospective large-scale multicenter randomized HORIZONS-AMI trial to evaluate the incidence, clinical correlates, and outcomes of in-hospital sustained VT/VF after PPCI. Of 3,485 patients undergoing PPCI in whom VT/VF did not occur before or during the procedure, 181 patients (5.2%) developed VT/VF after PPCI. Most postprocedural VT/VF episodes (85%) occurred in the first 48 hours. Patients with postprocedural VT/VF were more likely men with Killip class > I on presentation but had a lower prevalence of hypertension and diabetes. Patients with postprocedural VT/VF were also less frequently taking β blockers and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers at admission. Mean door-to-balloon time was shorter and Thrombolysis In Myocardial Infarction grade 0 flow before PPCI was more common in patients with VT/VF, although Thrombolysis In Myocardial Infarction grade 3 flow rates after PPCI did not vary. There were no significant differences in adjusted 3-year rates of mortality (hazard ratio 0.73, 95% confidence interval 0.30 to 1.79) or composite major adverse clinical events (death, myocardial infarction, target vessel revascularization, or stroke; hazard ratio 0.71, 95% confidence interval 0.44 to 1.15) in patients with versus without postprocedural sustained VT/VF. In conclusion, sustained VT/VF after PPCI in the HORIZONS-AMI trial was not significantly associated with 3-year mortality or major adverse clinical events. Further studies are required to address the prognostic significance of VT/VF in patients with STEMI undergoing PPCI.

Primary coronary intervention for ST-elevation myocardial infarction in Indonesia and the Netherlands: a comparison

Background. Although the beneficial effects of primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) have been demonstrated in a number of trials, most studies were conducted in Western countries. Experience, logistics and patient characteristics may differ in other parts of the world.Methods. Consecutive patients treated with primary PCI in Cinere Hospital, Jakarta, Indonesia, between January 2008 and October 2008 were compared with those treated in the Isala Clinics, Zwolle, the Netherlands.Results. During the study period, a total of 596 patients were treated by primary PCI, 568 in Zwolle and 28 in Jakarta. Patients in Indonesia were younger (54 vs 63 years), more often had diabetes (36 vs. 12%) and high lipids and were more often smokers (68 vs. 31%). Time delay between symptom onset and admission was longer in Indonesia. Patients from Indonesia more often had signs of heart failure at admission. The time between admission and balloon inflation was longer in Indonesia. At angiography, patients from Indonesia more often had multivessel disease. There was no difference in the percentage of restoration of TIMI 3 flow by primary PCI between the two hospitals.Conclusion. Patients with STEMI in Indonesia have a higher risk profile compared with those in the Netherlands, according to prevalence of coronary risk factors, signs of heart failure, multivessel disease and patient delay. Time delay between admission and balloon inflation was much longer in Indonesia, because of both logistic and financial reasons. (Neth Heart J 2009;17:418-21.).

Mortality implications of primary percutaneous coronary intervention treatment delays: insights from the Assessment of Pexelizumab in Acute Myocardial Infarction trial

BACKGROUND

Prior studies demonstrate a direct relationship between treatment delays to primary percutaneous intervention and mortality in patients with ST-segment elevation myocardial infarction (STEMI). This analysis compared the relationship of symptom onset-to-balloon time and door-to-balloon time on mortality in patients with STEMI.

METHODS AND RESULTS

We analyzed different treatment delays (symptom onset-to-balloon time, door-to-balloon time) and mortality in 5745 STEMI patients. Baseline characteristics, flow grade, 90-day mortality, and clinical outcomes were compared in patients stratified by treatment delay. Multivariable logistic regression modeling was performed to assess the independent and relative effect of each treatment delay on 90-day mortality. Female sex, increased age, and worse thrombolysis in myocardial infarction flow grade were significantly associated with longer symptom onset-to-balloon times and door-to-balloon times. Longer symptom onset-to-balloon time was significantly associated with worse 90-day mortality (3.7%, 4.2%, and 6.5% for time delays <3 hours, 3 to 5 hours, and >5 hours, respectively, P<0.0001). Similarly, longer door-to-balloon times were significantly associated with worse 90-day mortality (3.2%, 4.0%, 4.6%, and 5.3% for delays <60 minutes, 60 to 90 minutes, 90 to 120 minutes, and ≥120 minutes respectively, P<0.0001). In a multivariate model of 90-day mortality, door-to-balloon time (χ(2) 6.0, P<0.014), and symptom onset-to-hospital arrival (χ(2) 9.8, P<0.007) remained independent determinants.

CONCLUSIONS

Both symptom onset-to-balloon time and hospital door-to-balloon time are strongly associated with 90-day mortality following STEMI. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00091637.

Soluble guanylate cyclase-α1 is required for the cardioprotective effects of inhaled nitric oxide

Reperfusion injury limits the benefits of revascularization in the treatment of myocardial infarction (MI). Breathing nitric oxide (NO) reduces cardiac ischemia-reperfusion injury in animal models; however, the signaling pathways by which inhaled NO confers cardioprotection remain uncertain. The objective of this study was to learn whether inhaled NO reduces cardiac ischemia-reperfusion injury by activating the cGMP-generating enzyme, soluble guanylate cyclase (sGC), and to investigate whether bone marrow (BM)-derived cells participate in the sGC-mediated cardioprotective effects of inhaled NO. Wild-type (WT) mice and mice deficient in the sGC α(1)-subunit (sGCα(1)(-/-) mice) were subjected to cardiac ischemia for 1 h, followed by 24 h of reperfusion. During ischemia and for the first 10 min of reperfusion, mice were ventilated with oxygen or with oxygen supplemented with NO (80 parts per million). The ratio of MI size to area at risk (MI/AAR) did not differ in WT and sGCα(1)(-/-) mice that did not breathe NO. Breathing NO decreased MI/AAR in WT mice (41%, P = 0.002) but not in sGCα(1)(-/-) mice (7%, P = not significant). BM transplantation was performed to restore WT BM-derived cells to sGCα(1)(-/-) mice. Breathing NO decreased MI/AAR in sGCα(1)(-/-) mice carrying WT BM (39%, P = 0.031). In conclusion, these results demonstrate that a global deficiency of sGCα(1) does not alter the degree of cardiac ischemia-reperfusion injury in mice. The cardioprotective effects of inhaled NO require the presence of sGCα(1). Moreover, our studies suggest that BM-derived cells are key mediators of the ability of NO to reduce cardiac ischemia-reperfusion injury.

Impact of transfer for primary percutaneous coronary intervention on survival and clinical outcomes (from the HORIZONS-AMI Trial)

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy in patients with ST-segment elevation myocardial infarction (STEMI). We evaluated whether presentation of patients with STEMI to a noninterventional facility requiring transfer for primary PCI compared to direct admission to a PCI center has an impact on clinical outcomes. Of 3,602 patients enrolled in the multicenter, prospective HORIZONS-AMI trial, 988 (24.7%) were transferred for primary PCI and 2,614 were directly admitted to an interventional hospital. Clinical outcomes at 30 days and 1 year were evaluated. Median time to reperfusion in patients with transfer was 67 minutes longer compared to patients without transfer (272 vs 205 minutes, p <0.001), and first door-to-balloon time was 47 minutes longer (134 vs 87 minutes, p <0.001). At 30 days and 1 year there were no significant differences between patients with and without transfer in the rates of major adverse cardiac events (30 days 5.8% vs 5.4%, p = 0.68; 1 year 11.6% vs 12.0%, p = 0.74), major bleeding (30 days 7.3% vs 6.9%, p = 0.66; 1 year 7.9% vs 7.4%, p = 0.63), or mortality (30 days 2.6% vs 2.6%, p = 0.92; 1 year 4.0% vs 4.2%, p = 0.81). In transfer and nontransfer patients use of bivalirudin compared to unfractionated heparin plus glycoprotein IIb/IIIa inhibitor was associated with lower rates of bleeding, cardiac death, and net adverse clinical events. In conclusion, in the HORIZONS-AMI trial, 30-day and 1-year survival rates and clinical outcomes were comparable in patients with STEMI requiring and not requiring transfer for primary PCI.

Impact of primary coronary angioplasty delay on myocardial salvage, infarct size, and microvascular damage in patients with ST-segment elevation myocardial infarction: insight from cardiovascular magnetic resonance

OBJECTIVES

We investigated the extent and nature of myocardial damage by using cardiovascular magnetic resonance (CMR) in relation to different time-to-reperfusion intervals.

BACKGROUND

Previous studies evaluating the influence of time to reperfusion on infarct size (IS) and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) have yielded conflicting results.

METHODS

Seventy patients with STEMI successfully treated with primary percutaneous coronary intervention within 12 h from symptom onset underwent CMR 3 +/- 2 days after hospital admission. Patients were subcategorized into 4 time-to-reperfusion (symptom onset to balloon) quartiles: < or =90 min (group I, n = 19), >90 to 150 min (group II, n = 17), >150 to 360 min (group III, n = 17), and >360 min (group IV, n = 17). T2-weighted short tau inversion recovery and late gadolinium enhancement CMR were used to characterize reversible and irreversible myocardial injury (area at risk and IS, respectively); salvaged myocardium was defined as the normalized difference between extent of T2-weighted short tau inversion recovery and late gadolinium enhancement.

RESULTS

Shorter time-to-reperfusion (group I) was associated with smaller IS and microvascular obstruction and larger salvaged myocardium. Mean IS progressively increased overtime: 8% (group I), 11.7% (group II), 12.7% (group III), and 17.9% (group IV), p = 0.017; similarly, MVO was larger in patients reperfused later (0.5%, 1.5%, 3.7%, and 6.6%, respectively, p = 0.047). Accordingly, salvaged myocardium markedly decreased when reperfusion occurred >90 min of coronary occlusion (8.5%, 3.2%, 2.4%, and 2.1%, respectively, p = 0.004).

CONCLUSIONS

In patients with STEMI treated with primary percutaneous coronary intervention, time to reperfusion determines the extent of reversible and irreversible myocardial injury assessed by CMR. In particular, salvaged myocardium is markedly reduced when reperfusion occurs >90 min of coronary occlusion.

Stent thrombosis up to 3 years after stenting for ST-segment elevation myocardial infarction versus for stable angina--comparison of the effects of drug-eluting versus bare-metal stents

BACKGROUND

The long-term safety of drug-eluting stents (DES) for the treatment of ST-segment elevation myocardial infarction (STEMI) is unclear and may differ from that in stable angina (stable) patients as noted in autopsy studies.

METHODS

To assess this problem, 210 consecutive STEMI and 323 stable patients, randomized 2:1 to DES versus bare-metal stents (BMS), were followed up for 3 years for definite/probable stent thrombosis (ST) and cardiac death/myocardial infarction. Events occurring during the initial 6 months were separated from later events.

RESULTS

The 3-year rate of ST was 8.1% in STEMI vs 3.4% in stable patients (P = .02), with corresponding rates of 9.4% vs 2.9% (P = .01) for DES and of 5.6% vs 4.3% (P = .71) for BMS patients, respectively. This difference appeared only after 6 months: 4.6% in STEMI vs 1.7% in stable patients (P = .05) and in DES-treated patients (6.2% vs 2.0%, P = .05). Results of ST were paralleled by findings of clinical events, although here differences were less pronounced, but also seen only late after stenting. Thus, in STEMI patients, late events occurred more frequently after DES vs BMS implantation (11.6% vs 3.0%, P = .04), compared to results in stable patients (DES 6.4%, BMS 1.9%, P = .08).

CONCLUSIONS

In this pilot study, we observed an increased rate of late ST and a trend to more related clinical events in patients after stenting for STEMI vs for stable angina, particularly if treated with DES. This may explain outcome differences between results of pivotal trials in stable patients vs those of "real-world" patients.