Duration of ischemia is a major determinant of transmurality and severe microvascular obstruction after primary angioplasty: a study performed with contrast-enhanced magnetic resonance

Current and Future Roles of Glycoprotein IIb-IIIa Inhibitors in Primary Angioplasty for ST-Segment Elevation Myocardial Infarction

Acute myocardial infarction still represents the major cause of mortality in high-income countries. Therefore, considerable efforts have been focused on the treatment of myocardial infarctions in the acute and long-term phase, with special attention being paid to reperfusion strategies and adjunctive antithrombotic therapies. In fact, despite the successful mechanical recanalization of the epicardial conduit, a substantial percentage of patients still experience poor myocardial reperfusion or acute/subacute in-stent thrombosis. Due the delayed onset of action of currently available oral antiplatelet therapies, glycoprotein (GP) IIb-IIIa inhibitors could be expected to improve clinical outcomes, especially when administrated in the early phase of the infarction, due to the larger platelet composition of fresh thrombi, the dynamic nature of early thrombi, and the larger amount of viable myocardium existing in the early, as compared to a delayed, phase. Considerable evidence has accumulated regarding the benefits from GP IIb-IIIa inhibitors on mortality, especially among high-risk patients and when administered as an upstream strategy. Therefore, based on currently available data, GP IIb-IIIa inhibitors can be considered when the drug can be administered within the first 3 h of symptom onset and among high-risk patients (e.g., those with advanced Killip class or an anterior myocardial infarction). Even though it is not universally accepted, in our opinion, this strategy should be implemented in a pre-hospital setting (in an ambulance) or as soon as possible when arriving at the hospital (at the Emergency Room or Coronary Care Unit, irrespective of whether they are in spoke or hub hospitals). A new, second-generation GP IIb-IIIa inhibitor (zalunfiban) appears to be highly suitable as a pre-hospital pharmacological facilitation strategy at the time of first medical contact due to its favourable features, including its simple subcutaneous administration, rapid onset of action (15 min), and limited time of action (with a half-life of ~1 h), which is likely to minimize the risk of bleeding. The ongoing CELEBRATE trial, including 2499 STEMI patients, may potentially provide compelling data to support the upstream treatment of STEMI patients undergoing mechanical reperfusion. In fact, although the current therapeutic target of increased rates of timely reperfusion has been achieved, the future goal in myocardial infarction treatment should be to achieve the most rapid reperfusion prior to primary percutaneous coronary intervention, thus further minimizing myocardial damage, or, in some cases, even preventing it completely, and improving survival.

Treatment and Care of Patients with ST-Segment Elevation Myocardial Infarction-What Challenges Remain after Three Decades of Primary Percutaneous Coronary Intervention?

Primary percutaneous coronary intervention (pPCI) has revolutionized the prognosis of ST-segment elevation myocardial infarction (STEMI) and is the gold standard treatment. As a result of its success, the number of pPCI centres has expanded worldwide. Despite decades of advancements, clinical outcomes in STEMI patients have plateaued. Out-of-hospital cardiac arrest and cardiogenic shock remain a major cause of high in-hospital mortality, whilst the growing burden of heart failure in long-term STEMI survivors presents a growing problem. Many elements aiming to optimize STEMI treatment are still subject to debate or lack sufficient evidence. This review provides an overview of the most contentious current issues in pPCI in STEMI patients, with an emphasis on unresolved questions and persistent challenges.

Long-Term Prognostic Value of Infarct Transmurality Determined by Contrast-Enhanced Cardiac Magnetic Resonance after ST-Segment Elevation Myocardial Infarction

The long-term prognostic significance of maximal infarct transmurality evaluated by contrast-enhanced cardiac magnetic resonance (CE-CMR) in ST-segment elevation myocardial infarction (STEMI) patients has yet to be determined. This study aimed to see if maximal infarct transmurality has any additional long-term prognostic value over other CE-CMR predictors in STEMI patients, such as microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH). The study included 112 consecutive patients who underwent CE-CMR after STEMI to assess established parameters of myocardial injury as well as the maximal infarct transmurality. The primary clinical endpoint was the occurrence of major adverse cardiac events (MACE), which included all-cause death, non-fatal reinfarction, and new heart failure hospitalization. The MACE occurred in 10 patients over a median follow-up of 7.9 years (IQR, 5.8 to 9.2 years) (2 deaths, 3 nonfatal MI, and 5 heart failure hospitalization). Patients with MACE had significantly higher rates of transmural extent of infarction, infarct size >5.4 percent, MVO, and IMH compared to patients without MACE. In stepwise multivariable Cox regression analysis, the transmural extent of infarction defined as 75 percent or more of infarct transmurality was an independent predictor of the MACE after correction for MVO and IMH (hazard ratio 8.7, 95% confidence intervals [CIs] 1.1-71; p=0.043). In revascularized STEMI patients, post-infarction CE-CMR-based maximal infarct transmurality is an independent long-term prognosticator. Adding maximal infarct transmurality to CE-CMR parameters like MVO and IMH could thus identify patients at high risk of long-term adverse outcomes in STEMI.

Coronary microvascular obstruction and dysfunction in patients with acute myocardial infarction

Despite prompt epicardial recanalization in patients presenting with ST-segment elevation myocardial infarction (STEMI), coronary microvascular obstruction and dysfunction (CMVO) is still fairly common and is associated with poor prognosis. Various pharmacological and mechanical strategies to treat CMVO have been proposed, but the positive results reported in preclinical and small proof-of-concept studies have not translated into benefits in large clinical trials conducted in the modern treatment setting of patients with STEMI. Therefore, the optimal management of these patients remains a topic of debate. In this Review, we appraise the pathophysiological mechanisms of CMVO, explore the evidence and provide future perspectives on strategies to be implemented to reduce the incidence of CMVO and improve prognosis in patients with STEMI.

Upstream anticoagulation in patients with ST-segment elevation myocardial infarction: a systematic review and meta-analysis

BACKGROUND AND AIM

Parenteral anticoagulation is recommended for all patients presenting with ST-segment elevation myocardial infarction (STEMI) during primary percutaneous coronary intervention (PPCI). Whether upstream anticoagulation improves clinical outcomes is not well established. We conducted a systematic review and meta-analysis of contemporary evidence on parenteral anticoagulation timing for STEMI patients.

METHODS

We performed a systematic search of electronic databases (PubMed, CENTRAL, and Scopus) until December 2022. Studies were eligible if they (a) compared upstream anticoagulation with administration at the catheterization laboratory and (b) enrolled patients with STEMI undergoing PPCI. Efficacy outcomes included in-hospital or 30-day mortality, in-hospital cardiogenic shock (CS), and TIMI flow grade pre- and post-PPCI. Safety outcome was defined as in-hospital or 30-day major bleeding.

RESULTS

Overall, seven studies were included (all observational), with a total of 69,403 patients. Upstream anticoagulation was associated with a significant reduction in the incidence of in-hospital or 30-day all-cause mortality (OR 0.61; 95% CI 0.45-0.81; p < 0.001) and in-hospital CS (OR 0.68; 95% CI 0.58-0.81; p < 0.001) and with an increase in spontaneous reperfusion (pre-PPCI TIMI > 0: OR 1.46; 95% CI 1.35-1.57; p < 0.001). Pretreatment was not associated with an increase in major bleeding (OR 1.02; 95% CI 0.70-1.48; p = 0.930).

CONCLUSIONS

Upstream anticoagulation was associated with a significantly lower risk of 30-day all-cause mortality, incidence of in-hospital CS, and improved reperfusion of the infarct-related artery (IRA). These findings were not accompanied by an increased risk of major bleeding, suggesting an overall clinical benefit of early anticoagulation in STEMI. These results require confirmation in a dedicated randomized clinical trial.

Cardiac Magnetic Resonance-Detected Acute Myocardial Edema as Predictor of Favourable Prognosis: A Comprehensive Review

Acute myocardial edema (AME) is increased water content in the myocardium and represents the first and transient pathophysiological response to an acute myocardial injury. In-vivo and non-invasive evaluation is feasible with cardiac magnetic resonance (CMR), which is a powerful imaging technique capable of tissue characterization. In the clinical setting, early demonstration of AME has a recognized diagnostic value for acute coronary syndromes and acute myocarditis, although its prognostic value is not well established. This article provides a comprehensive narrative review on the clinical meaning of AME in heart diseases. In particular, the available evidence of a possible favourable prognostic value in several clinical scenarios is addressed.

Relationship between Hemoglobin Concentration at Admission with the Incidence of No-Reflow Phenomenon and In-Hospital Mortality in Acute Myocardial Infarction with Elevation of ST Segments in Patients who underwent Primary Percutaneous Coronary Intervention

Anemia in acute ST-segment elevation myocardial infarction (STEMI) is associated with a pro-coagulant state, contributing to the incidence of no-reflow phenomenon and increased mortality following primary percutaneous coronary intervention (PPCI). However, clinical data remain contradictory. The objective of our study was to evaluate the association of admission hemoglobin (Hb) concentration and in-hospital mortality of STEMI patients' post-PPCI, as well as final thrombolysis in myocardial infarction (TIMI) flow. A cross-sectional study was performed from the database of Jakarta Acute Coronary Syndrome Registry, consisting of 3,071 STEMI patients who underwent PPCI between January 2014 and December 2019. No-reflow phenomenon was defined as final TIMI flow <3 of the infarct-related artery. Outcome measures were the occurrence of no-reflow and in-hospital mortality. Anemia criteria were based on the World Health Organization. Anemia was found in 550 patients (17.9%). Patients with anemia were older (60 ± 10 years, p < 0.001), predominantly women (20.7 vs. 11.2%, p < 0.001), TIMI risk score >4 (45.8 vs. 30.4%, p < 0.00), and Killip classification >1 (25.8 vs. 20.8%, p < 0.009). Anemia at admission was not associated with no-reflow phenomenon (odds ratio [OR] = 0.889; 95% confidence interval [CI] = 0.654–1.209, p = 0.455). Multivariate regression models showed that anemia was not associated with in-hospital mortality (OR = 0.963; 95% CI = 0.635–1.459, p = 0.857) and with no-reflow phenomenon (OR = 0.939; 95% CI = 0.361–2.437, p = 0.896). Anemia upon admission was not related to the no-reflow phenomena or in-hospital mortality in STEMI patients undergoing PPCI.

Impact of Total Ischemic Time on the Recovery of Regional Wall Motion Abnormality after STEMI in the Modern Reperfusion Era

Background

Total ischemic time (TIT) is an important factor for predicting mortality among patients with ST-segment elevation myocardial infarction (STEMI). However, the correlation between TIT and the extent of wall motion abnormality has not been well studied. Therefore, we investigated changes in the wall motion score index (WMSI) value based on TIT in STEMI patients who underwent primary percutaneous coronary intervention (PCI) and subsequent transthoracic echocardiography.

Methods

STEMI patients who underwent primary PCI and follow-up coronary angiography were analyzed after the exclusion of cases of in-stent restenosis (ISR). WMSI values were calculated by dividing the sum of scores by the number of segments visualized.

Results

A total of 189 patients underwent primary PCI for STEMI, and 151 had no ISR with a median follow-up of 12.3 months. TIT was 180 (117–369) minutes in a subset of 151 patients (mean age of 62 years; 76% male). Among patients without ISR, 109 (72%) demonstrated a decrease in the WMSI value during the follow-up period. The WMSI values of patients with TITs of 180 minutes or less were significantly decreased relative to those among patients with TITs of greater than 180 minutes (p=0.020). Among patients with TITs of 180 minutes or less, the TIT was significantly shorter among those with a reduction in the WMSI value than among those with an increase in the WMSI value (106 [81–124] vs. 133 [100–151] minutes; p=0.018). TIT was an independent predictor for a reduction in the WMSI value among these patients (adjusted hazard ratio: 0.976 (0.957–0.995); p=0.016).

Conclusions

In the modern reperfusion era of STEMI, patients with TITs of 180 minutes or less experienced a significant degree of recovery from regional wall motion abnormalities.

The relationship between symptom onset-to-needle time and ischemic outcomes in patients with acute myocardial infarction treated with primary PCI: Observations from Prague-18 Study

OBJECTIVES

Based on previous studies with clopidogrel, the time between acute myocardial infarction (AMI) symptoms onset and primary percutaneous coronary intervention (PCI) was proven as important prognostic factor. Our aim was to assess the relationship between symptoms onset to needle time (SNT) and procedural results and the occurrence of ischemic endpoints in primary angioplasty patients treated with potent P2Y12 inhibitors.

METHODS

A total of 1,131 out of 1,230 patients randomized to the Prague-18 study (prasugrel vs. ticagrelor in primary PCI) were divided into a high and a low-risk group. The effect of defined SNT on patients' ischemic endpoints and prognosis by their risk status at admission was tested.

RESULTS

The median SNT was 3.2 hours. Longer SNTs resulted in a more frequent incidence of TIMI flow <3 post PCI (p=0.015). There were significant differences in the occurrence of the combined ischemic endpoint among the compared SNT groups at 30 days (p=0.032), and 1 year (p=0.011), with the highest incidence in the ≤1 h SNT group of patients. "Latecomers" (SNT>4 hs) in the high-risk group experienced more reinfarction within 1 year [OR (95% CI) 3.23 (1.09-9.62) p=0.035]; no difference was found in the low-risk group.

CONCLUSIONS

In the era of intense antithrombotic medication, stratification of MI patients undergoing primary angioplasty, based on initial ischemic risk assessment affected prognosis more than symptom onset to needle time. Longer time delay was significantly related to increased incidence of ischemic events and all-cause mortality only in patients with high ischemic risk.

A Clinical Score to Predict "Corrected Thrombolysis in Myocardial Infarction Frame Count" in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Corrected thrombolysis in myocardial infarction frame count (cTFC) is an objective, simple, and reproducible method to assess coronary blood flow which is a surrogate for cardiovascular outcomes. It is important to learn which factors are associated with cTFC. The goal of this study was to determine predictive models for epicardial blood flow assessed by cTFC and develop a diagnostic predictive model that indicates the individualized assessment of epicardial blood flow prior to primary percutaneous coronary intervention. This is a retrospective study including 3205 patients with ST-segment elevation myocardial infarction who underwent pPCI. The primary outcome was cTFC. Multivariable linear regression analysis was performed. Subsequently, a nomogram was developed to predict cTFC according to the candidate predictors. Median age was 58; the number of male patients was 2381 (74.3%). Median value of cTFC was 22 and interquartile range (IQR): 16.5-28.0). Age, diabetes mellitus (DM), total ischemic time, systolic blood pressure (SBP), heart rate (HR), and history of statin use remained in both full and reduced models. Our model may potentially allow clinicians to identify patients at high risk for impaired epicardial perfusion.

Global Strain Measured by Three-Dimensional Speckle Tracking Echocardiography Is a Useful Predictor for 10-Year Prognosis After a First ST-Elevation Acute Myocardial Infarction

BACKGROUND

Three-dimensional (3D) speckle tracking echocardiography (STE) after ST-elevation acute myocardial infarction (STEMI) is associated with left ventricular (LV) remodeling and 1-year prognosis. This study investigated the clinical significance of 3D-STE in predicting the long-term prognosis of patients with STEMI.

METHODS AND RESULTS

A total of 270 patients (mean age 64.6 years) with first-time STEMI treated with reperfusion therapy were enrolled. At 24 h after admission, standard 2D echocardiography and 3D full-volume imaging were performed, and 2D-STE and 3D-STE were calculated. Patients were followed up for a median of 119 months (interquartile range: 96-129 months). The primary endpoint was occurrence of a major adverse cardiac event (MACE: cardiac death, heart failure with hospitalization), and 64 patients experienced MACEs. Receiver operating characteristic curves and Cox hazard multivariate analysis showed that the 3D-STE indices were stronger predictors of MACE compared with those of 2D-STE. Additionally, 3D-global longitudinal strain (GLS) was the strongest predictor for MACE followed by 3D-global circumferential strain (GCS). The Kaplan-Meier curve demonstrated that 3D-GLS >-11.0 was an independent predictor for MACE (log-rank χ2=132.2, P<0.0001). When combined with 3D-GCS >-18.3, patients with higher values of 3D-GLS and 3D-GCS were found to be at extremely high risk for MACE.

CONCLUSIONS

Global strain measured by 3D-STE immediately after the onset of STEMI is a clinically significant predictor of 10-year prognosis.

Impact in total ischemic time and ST-segment elevation myocardial infarction admissions during COVID-19

BACKGROUND

Despite the COVID-19 pandemic, cardiovascular disease is still the main cause of death in developed countries. Of these deaths, acute coronary syndromes (ACS) account for a substantial percentage of deaths. Improvement in ACS outcomes, are achieved by reducing the time from symptom onset until reperfusion or total ischemic time (TIT). Nevertheless, due to the overwhelming reality at the beginning of the pandemic, acute coronary syndrome (ACS) care may have been compromised.

OBJECTIVES

We evaluated delays in TIT based on the date and timing of admissions in patients with STEMI, by a timeline follow-up form, before and during the current COVID-19 pandemic.

METHODS

Between July 2018 and June 2020, two hundred and twelve patients diagnosed with ST-segment elevation myocardial infarction (STEMI) were admitted to our medical center. Upon presentation, cases were assigned a timeline report sheet and each time interval, from onset of symptoms to the catheterization lab, was documented. The information was later evaluated to study potential excessive delays throughout ACS management.

RESULTS

Our data evidenced that during the COVID-19 pandemic ACS admissions were reduced by 34.54%, in addition to several in-hospital delays in patient's ACS management including delays in door-to-ECG time (9.43 ± 18.21 vs. 18.41 ± 28.34, p = 0.029), ECG-to-balloon (58.25 ± 22.59 vs. 74.39 ± 50.30, p = 0.004) and door-to-balloon time (57.41 ± 27.52 vs. 69.31 ± 54.14, p = 0.04).

CONCLUSIONS

During the pandemic a reduction in ACS admissions occurred in our hospital that accompanied with longer in-hospital TIT due to additional tests, triage, protocols to protect and prevent infection within hospital staff, and maintenance of adequate standards of care. However, door-to-balloon time was maintained under 90 min.

Time course of coronary flow capacity impairment in ST-segment elevation myocardial infarction

BACKGROUND

Microvascular dysfunction in the setting of ST-elevated myocardial infarction (STEMI) plays an important role in long-term poor clinical outcome. Coronary flow reserve (CFR) is a well-established physiological parameter to interrogate the coronary microcirculation. Together with hyperaemic average peak flow velocity, CFR constitutes the coronary flow capacity (CFC), a validated risk stratification tool in ischaemic heart disease with significant prognostic value. This mechanistic study aims to elucidate the time course of the microcirculation as reflected by alterations in microcirculatory physiological parameters in the acute phase and during follow-up in STEMI patients.

METHODS

We assessed CFR and CFC in the culprit and non-culprit vessel in consecutive STEMI patients at baseline (n = 98) and after one-week (n = 64) and six-month follow-up (n = 65).

RESULTS

A significant trend for culprit CFC in infarct size as determined by peak troponin T (p = 0.004), time to reperfusion (p = 0.038), the incidence of final Thrombolysis In Myocardial Infarction 3 flow (p = 0.019) and systolic retrograde flow (p = 0.043) was observed. Non-culprit CFC linear contrast analysis revealed a significant trend in C-reactive protein (p = 0.027), peak troponin T (p < 0.001) and heart rate (p = 0.049). CFC improved both in the culprit and the non-culprit vessel at one-week (both p < 0.001) and six-month follow-up (p = 0.0013 and p < 0.001) compared with baseline.

CONCLUSION

This study demonstrates the importance of microcirculatory disturbances in the setting of STEMI, which is relevant for the interpretation of intracoronary diagnostic techniques which are influenced by both culprit and non-culprit vascular territories. Assessment of non-culprit vessel CFC in the setting of STEMI might improve risk stratification of these patients following coronary reperfusion of the culprit vessel.

Epicardial Surface Area of Infarction: A Stable Surrogate of Microvascular Obstruction in Acute Myocardial Infarction

BACKGROUND

Microvascular obstruction (MO) is a pathophysiologic complication of acute myocardial infarction that portends poor prognosis; however, it is transient and disappears with infarct healing. Much remains unknown regarding its pathophysiology and whether there are predictors of MO that could function as stable surrogates. We tested for clinical and cardiovascular magnetic resonance predictors of MO to gain insight into its pathophysiology and to find a stable surrogate.

METHODS

Three hundred two consecutive patients from 2 centers underwent cardiovascular magnetic resonance within 2 weeks of first acute myocardial infarction. Three measures of infarct morphology: infarct size, transmurality, and a new index-the epicardial surface area (EpiSA) of full-thickness infarction-were quantified on delayed-enhancement cardiovascular magnetic resonance.

RESULTS

Considering all clinical characteristics, only measures of infarct morphology were independent predictors of MO. EpiSA was the strongest predictor of MO and provided incremental predictive value beyond that of infarct size and transmurality (P<0.0001). In patients with 3-month follow-up cardiovascular magnetic resonance (n=81), EpiSA extent remained stable while MO disappeared, and EpiSA was a predictor of adverse ventricular remodeling. After 20 months of follow-up, 11 died and 1 had heart transplantation. Patients with an EpiSA larger than the median value (≥6%) had worse outcome than those with less than the median value (adverse events: 6.4% versus 1.9%, P=0.045).

CONCLUSIONS

The EpiSA of infarction is a novel index of infarct morphology which accurately predicts MO during the first 2 weeks of MI, but unlike MO, does not disappear with infarct healing. This index has potential as a stable surrogate of the presence of acute MO and may be useful as a predictor of adverse remodeling and outcome which is less dependent on the time window of patient assessment.

Duration of Inducible Ventricular Tachycardia Early After ST-Segment-Elevation Myocardial Infarction and Its Impact on Mortality and Ventricular Tachycardia Recurrence

Background

The clinical significance of the duration of inducible ventricular tachycardia (VT) at electrophysiology study (EPS) in patients soon after ST‐segment–elevation myocardial infarction and its predictive utility for VT recurrence are not known.

Methods and Results

Consecutive ST‐segment–elevation myocardial infarction patients with day 3 to 5 left ventricular ejection fraction ≤40% underwent EPS. A positive EPS was defined as sustained monomorphic VT with cycle length ≥200 ms. The induced VT was terminated by overdrive pacing or direct current shock at 30 s or earlier if hemodynamic decompensation occurred. Patients with inducible VT duration 2 to 10 s were compared with patients with inducible VT >10 s. The primary end point was survival free of VT or cardiac mortality. From 384 consecutive ST‐segment–elevation myocardial infarction patients who underwent EPS, 29% had inducible VT (n=112, 87% men). After mean follow‐up of 5.9±3.9 years, primary end point occurred in 35% of patients with induced VT 2 to 10 s duration (n=68) and in 22% of patients with induced VT >10 s (n=41) (P=0.61). This was significantly different from the noninducible VT group, in which primary end point occurred in 3% of patients (n=272) (P=0.001).

Conclusions

This study is the first to show that in patients who undergo EPS early after myocardial infarction, inducible VT of short duration (2–10 s) has similar predictive utility for ventricular tachyarrhythmia as longer duration (>10 s) inducible VT, which was significantly different to those without inducible VT. It is possible that immediate cardioversion of rapid VT might have contributed to some of the short durations of inducible VT.

Low-Dose Alteplase During Primary Percutaneous Coronary Intervention According to Ischemic Time

BACKGROUND

Microvascular obstruction affects one-half of patients with ST-segment elevation myocardial infarction and confers an adverse prognosis.

OBJECTIVES

This study aimed to determine whether the efficacy and safety of a therapeutic strategy involving low-dose intracoronary alteplase infused early after coronary reperfusion associates with ischemic time.

METHODS

This study was conducted in a prospective, multicenter, parallel group, 1:1:1 randomized, dose-ranging trial in patients undergoing primary percutaneous coronary intervention. Ischemic time, defined as the time from symptom onset to coronary reperfusion, was a pre-specified subgroup of interest. Between March 17, 2016, and December 21, 2017, 440 patients, presenting with ST-segment elevation myocardial infarction within 6 h of symptom onset (<2 h, n = 107; ≥2 h but <4 h, n = 235; ≥4 h to 6 h, n = 98), were enrolled at 11 U.K. hospitals. Participants were randomly assigned to treatment with placebo (n = 151), alteplase 10 mg (n = 144), or alteplase 20 mg (n = 145). The primary outcome was the amount of microvascular obstruction (MVO) (percentage of left ventricular mass) quantified by cardiac magnetic resonance imaging at 2 to 7 days (available for 396 of 440).

RESULTS

Overall, there was no association between alteplase dose and the extent of MVO (p for trend = 0.128). However, in patients with an ischemic time ≥4 to 6 h, alteplase increased the mean extent of MVO compared with placebo: 1.14% (placebo) versus 3.11% (10 mg) versus 5.20% (20 mg); p = 0.009 for the trend. The interaction between ischemic time and alteplase dose was statistically significant (p = 0.018).

CONCLUSION

In patients presenting with ST-segment elevation myocardial infarction and an ischemic time ≥4 to 6 h, adjunctive treatment with low-dose intracoronary alteplase during primary percutaneous coronary intervention was associated with increased MVO. Intracoronary alteplase may be harmful for this subgroup. (A Trial of Low-Dose Adjunctive Alteplase During Primary PCI [T-TIME]; NCT02257294).

Acute alterations in glucose homeostasis impact coronary microvascular function in patients presenting with ST-segment elevation myocardial infarction

Background

Microvascular dysfunction in the setting of ST-segment myocardial infarction (STEMI) is thought to be related to stress-related metabolic changes, including acute glucose intolerance. The aim of this study was to assess the relationship between admission glucose levels and microvascular function in non-diabetic STEMI patients.

Methods

92 consecutive patients with a first anterior-wall STEMI treated with primary percutaneous coronary intervention (PPCI) were enrolled. Blood glucose levels were determined immediately prior to PPCI. After successful PPCI, at 1‑week and 6‑month follow-up, Doppler flow was measured in culprit and reference coronary arteries to calculate coronary flow velocity reserve (CFVR), baseline (BMR) and hyperaemic (HMR) microvascular resistance.

Results

The median admission glucose was 8.3 (7.2–9.6) mmol/l respectively 149.4 mg/dl [129.6–172.8] and was significantly associated with peak troponin T (standardised beta coefficient [std beta] = 0.281; p = 0.043). Multivariate analysis revealed that increasing glucose levels were significantly associated with a decrease in reference vessel CFVR (std beta = −0.313; p = 0.002), dictated by an increase in rest average peak velocity (APV) (std beta = 0.216; p = 0.033), due to a decreasing BMR (std beta = −0.225; p = 0.038) in the acute setting after PPCI. These associations disappeared at follow-up. These associations were not found for the infarct-related artery.

Conclusion

Elevated admission glucose levels are associated with impaired microvascular function assessed directly after PPCI in first anterior-wall STEMI. This influence of glucose levels is an acute phenomenon and contributes to microvascular dysfunction through alterations in resting flow and baseline microvascular resistance.

Pre-hospital delay and emergency medical services in acute myocardial infarction

BACKGROUND/AIMS

Minimising total ischemic time (TIT) is important for improving clinical outcomes in patients with ST-segment elevation myocardial infarction who have undergone percutaneous coronary intervention (PCI). TIT has not shown a significant improvement due to persistent pre-hospital delay. This study aimed to investigate the risk factors associated with pre-hospital delay.

METHODS

Individuals enrolled in the Korea Acute Myocardial Infarction Registry-National Institutes of Health between 2011 and 2015 were included in this study. The study population was analyzed according to the symptom-to-door time (STDT; within 60 or > 60 minutes), and according to the type of hospital visit (emergency medical services [EMS], non-PCI center, or PCI center).

RESULTS

A total of 4,874 patients were included in the analysis, of whom 28.4% arrived at the hospital within 60 minutes of symptom-onset. Old age (> 65 years), female gender, and renewed ischemia were independent predictors of delayed STDT. Utilising EMS was the only factor shown to reduce STDT within 60 minutes, even when cardiogenic shock was evident. The overall frequency of EMS utilisation was low (21.7%). Female gender was associated with not utilising EMS, whereas cardiogenic shock, previous myocardial infarction, familial history of ischemic heart disease, and off-hour visits were associated with utilising EMS.

CONCLUSION

Factors associated with delayed STDT and not utilising EMS could be targets for preventive intervention to improve STDT and TIT.

Time-Dependent Myocardial Necrosis in Patients With ST-Segment-Elevation Myocardial Infarction Without Angiographic Collateral Flow Visualized by Cardiac Magnetic Resonance Imaging: Results From the Multicenter STEMI-SCAR Project

Background Acute complete occlusion of a coronary artery results in progressive ischemia, moving from the endocardium to the epicardium (ie, wavefront). Dependent on time to reperfusion and collateral flow, myocardial infarction ( MI ) will manifest, with transmural MI portending poor prognosis. Late gadolinium enhancement cardiac magnetic resonance imaging can detect MI with  high diagnostic accuracy. Primary percutaneous coronary intervention is the preferred reperfusion strategy in patients with ST -segment-elevation MI with <12 hours of symptom onset. We sought to visualize time-dependent necrosis in a population with ST -segment-elevation MI by using late gadolinium enhancement cardiac magnetic resonance imaging (STEMI-SCAR project). Methods and Results ST -segment-elevation MI patients with single-vessel disease, complete occlusion with TIMI (Thrombolysis in Myocardial Infarction) score 0, absence of collateral flow (Rentrop score 0), and symptom onset <12 hours were consecutively enrolled. Using late gadolinium enhancement cardiac magnetic resonance imaging, the area at risk and infarct size, myocardial salvage index, transmurality index, and transmurality grade (0-50%, 51-75%, 76-100%) were determined. In total, 164 patients (aged 54±11 years, 80% male) were included. A receiver operating characteristic curve (area under the curve: 0.81) indicating transmural necrosis revealed the best diagnostic cutoff for a symptom-to-balloon time of 121 minutes: patients with >121 minutes demonstrated increased infarct size, transmurality index, and transmurality grade (all P<0.01) and decreased myocardial salvage index ( P<0.001) versus patients with symptom-to-balloon times ≤121 minutes. Conclusions In MI with no residual antegrade and no collateral flow, immediate reperfusion is vital. A symptom-to-balloon time of >121 minutes causes a high grade of transmural necrosis. In this pure ST -segment-elevation MI population, time to reperfusion to salvage myocardium was less than suggested by current guidelines.

Coronary flow reserve is related to the extension and transmurality of myocardial necrosis and predicts functional recovery after acute myocardial infarction

BACKGROUND

Few studies have examined the effect of transmurality of myocardial necrosis on coronary microcirculation. The aim of this study was to examine the influence of cardiac magnetic resonance-derived (GE-MRI) structural determinants of coronary flow reserve (CFR) after anterior myocardial infarction (STEMI), and their predictive value on regional functional recovery.

METHODS

Noninvasive CFR and GE-MRI were studied in 37 anterior STEMI patients after primary coronary angioplasty. The wall motion score index in the left descending anterior coronary artery territory (A-WMSI) was calculated at admission and follow-up (FU). Recovery of regional left ventricular (LV) function was defined as the difference in A-WMSI at admission and FU. The necrosis score index (NSI) and transmurality score index (TSI) by GE-MRI were calculated in the risk area. Baseline (BMR) and hyperemic (HMR) microvascular resistance, arteriolar resistance index (ARI), and coronary resistance reserve (CRR) were calculated at the Doppler echocardiography.

RESULTS

Bivariate analysis indicated that the CPK and troponin I peak, heart rate, NSI, TSI, BMR, the ARI, and CRR were related to CFR. Multivariable analysis revealed that TSI was the only independent determinant of CFR. The CFR value of >2.27, identified as optimal by ROC analysis, was 77% specific and 73% sensitive with accuracy of 76% in identifying patients with functional recovery.

CONCLUSIONS

Preservation of microvascular function after AMI is related to the extent of transmurality of myocardial necrosis, is an important factor influencing regional LV recovery, and can be monitored by noninvasive CFR.

The role of sphingosine 1 phosphate in coronary artery disease and ischemia reperfusion injury

Coronary artery disease (CAD) is a common cause of morbidity and mortality worldwide. Atherosclerotic plaques, as a hallmark of CAD, cause chronic narrowing of coronary arteries over time and could also result in acute myocardial infarction (AMI). The standard treatments for ameliorating AMI are reperfusion strategies, which paradoxically result in ischemic reperfusion (I/R) injury. Sphingosine 1 phosphate (S1P), as a potent lysophospholipid, plays an important role in various organs, including immune and cardiovascular systems. In addition, high-density lipoprotein, as a negative predictor of atherosclerosis and CAD, is a major carrier of S1P in blood circulation. S1P mediates its effects through binding to specific G protein-coupled receptors, and its signaling contributes to a variety of responses, including cardiac inflammation, dysfunction, and I/R injury protection. In this review, we will focus on the role of S1P in CAD and I/R injury as a potential therapeutic target.

Utility of Hematological Parameters in Predicting No-Reflow Phenomenon After Primary Percutaneous Coronary Intervention in Patients With ST-Segment Elevation Myocardial Infarction

Objective:

Because the no-reflow phenomenon in patients with ST- segment elevation myocardial infarction can lead to poor outcomes and early identification of patients at high risk may alter the clinical outcome, we aimed to study possible differences in the predictive utility among hematological parameters for early identification of patients at high risk of the no-reflow phenomenon during the primary percutaneous coronary intervention.

Methods:

A total of 612 patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention were enrolled. The patients were divided into 2 groups: no-reflow and normal reflow. Hematological parameters were measured on admission. Sensitivity, specificity, positive and negative predictive values, and receiver–operating characteristic areas under the curve were determined to evaluate the predictive values of these parameters.

Results:

The patients in the no-reflow group had a significantly higher neutrophil count, neutrophil–lymphocyte ratio, platelet–lymphocyte ratio, and mean platelet volume-to-lymphocyte ratio when compared to the normal reflow patients. We identified mean platelet volume-to-lymphocyte ratio to have a moderate predictive value and high specificity (66.8%) for the no-reflow phenomenon. Neutrophil–lymphocyte ratio provided the largest area under the curve for predicting no reflow. Regarding the predictive utility for no reflow, the comparison showed no statically significant differences among evaluated hematological parameters.

Conclusion:

For the prediction of no reflow, mean platelet volume-to-lymphocyte ratio yielded moderate performance. No hematological parameter on admission had persuasive superior capacities to predict no-reflow in patients receiving the primary percutaneous coronary intervention.

Developments in pre-hospital patient transport in ST-elevation myocardial infarction

INTRODUCTION

ST-elevation myocardial infarction (STEMI) is a medical emergency that benefits from rapid access to specialized care. The objective of this study was to describe developments in patient transport via the pre-hospital emergency medical system (EMS) and its impact on clinical outcomes.

METHODS

We retrospectively studied STEMI patients who underwent primary percutaneous coronary intervention between January 2008 and July 2015. Patients were divided according to type of admission. Total ischemic time (TIT), door-to-balloon time (DBT) and in-hospital and one-year clinical outcomes were assessed for each group.

RESULTS

A total of 764 patients were included, of whom 33.5% were transported by the EMS and 45.8% by their own means, 13.7% were transferred from another institution and 6.9% were transported by non-EMS ambulance. There was a trend for more frequent recourse to the EMS over the eight-year period. There was a higher percentage of patients with prior myocardial infarction and Killip class III/IV in the EMS group compared to the non-EMS group. Significant differences were seen between groups in reperfusion times, EMS patients having the shortest TIT and DBT (195 vs. 286 min, p<0.001 and 61 vs. 90 min, p<0.001, respectively), but no significant difference in event rates was observed. Patients presenting to the hospital early had higher rates of effective reperfusion and lower in-hospital mortality (6.9% vs. 33.9%, p<0.001).

CONCLUSIONS

Recourse to the EMS significantly reduced ischemic times. Although this improvement was not directly associated with significant differences in event rates, it was associated with higher rates of effective reperfusion that were reflected in lower in-hospital mortality.

Cardiac Magnetic Resonance and Myocardial Viability: Why Is It so Important?

For a better assessment of ischemic heart diseases, myocardial viability should be quantified. Current studies underline the importance and the evolution of several techniques and methods used in the evaluation of myocardial viability. Taking into account these considerations, the aim of this manuscript was to present the recent points of view regarding myocardial viability and its clinical significance in patients with ischemic cardiomyopathies and left ventricular dysfunction. On the other hand, the manuscript points out the role of magnetic resonance imaging (MRI), one of the most useful noninvasive imaging techniques, in the assessment of myocardial viability. By comparing the advantages and disadvantages of cardiac MRI, its usefulness can be better appreciated by the clinician. In the following years, it is considered that MRI will be an indispensable imaging tool in the assessment of ischemic heart disease, guiding interventions for revascularization and long-term risk stratification in patients with stable angina or myocardial infarction.

Magnetic Resonance Imaging in Myocardial Fibrosis Related to Ischemic Events

Given the higher amount of detail it offers, the use of magnetic resonance (MR) in the field of cardiology has increased, thus leading to a decrease in the use of invasive and irradiating methods for diagnosing various cardiovascular disorders. The only precautions for MR imaging are metallic implants and advanced-stage chronic kidney disease. For the acquisition of clear and dynamic myocardial images, methods such as spin echo imaging for anatomical description, steady-state free precession imaging for the assessment of ventricular cavity size and function, flow velocity encoding for blood flow measurements, radiofrequency tagging for dynamics, and even spectroscopy for metabolism evaluation are used. Cardiac magnetic resonance (CMR) is considered the gold standard imaging method for the anatomical characterization of the heart and obtaining information related to myocardial dynamics. In case of ischemic events, CMR is used for a detailed description of the necrotic area and the complications, and for tracking the ventricular remodeling. By administrating a contrast agent (gadolinium), the difference between sub-endothelial and transmural infarctions can be distinguished, highlighting even microvascular lesions responsible for the extension of the necrosis. The assessment of the dynamics of ventricular remodeling and viability through late gadolinium enhancement (LGE) technology highlights the area of fibrosis and the occurrence of late complications.

Role of Cardiac Magnetic Resonance Imaging in Myocardial Infarction

PURPOSE OF REVIEW

The purpose of the present paper is to analytically review the diagnostic and prognostic role of CMR in ST-segment elevation myocardial infarction (STEMI) survivors. Percutaneous coronary intervention (PCI) is the treatment of choice in patients STEMI. However, risk of future events remains substantial. Assessment of the extent of myocardial infarction (MI), cardiac function and ventricular remodelling has become the focus of recent studies. Electrocardiography, angiography and echocardiography parameters, as well as risk scores, lack sensitivity and reproducibility in predicting future cardiovascular events. A major advantage of cardiac magnetic resonance imaging (CMR) is that it provides myocardial tissue characterization.

RECENT FINDINGS

CMR is able to quantify both reversible and irreversible myocardial injury and correlates with future events. This review will illustrate how microvascular function indices (myocardial salvage index, presence and amount of microvascular obstruction and intramyocardial haemorrhage) detectable by CMR add prognostic information and could impact on future strategies to improve outcomes in revascularized patients.

Experience and Outcomes of Primary Percutaneous Coronary Intervention for Patients with ST-Segment Elevation Myocardial Infarction of Tertiary Care Center in Bosnia and Herzegovina

BACKGROUND

Primary percutaneous coronary intervention (PCI) is an emergent percutaneous catheter intervention in the setting of ST-segment elevations myocardial infarction (STEMI), without previous fibrinolytic treatment.

AIM

To evaluate the feasibility and outcomes of primary percutaneous coronary interventions for STEMI in regional tertiary care cardiac centre in Bosnia and Herzegovina.

METHODS

Between January 2014 and December 2016, consecutive 549 STEMI patients who underwent primary PCI were prospectively enrolled in a primary PCI registry. The most of coronary angiography procedures were performed using the radial artery route. Patient demographics, risk factors, procedural characteristics, time variables and in-hospital events were assessed.

RESULTS

On admission, 297 (64.7%) of the patients were current smokers, 234 (42.6%) were hypertensive, 172 (31.3%) were diabetics, and 68 (12.3%) had cardiogenic shock. The mean duration of time from symptom onset to hospital arrival 193±118.2 minutes, and the mean door-to-balloon time was 37±11.3 minutes and median total ischemic time was 265(60-897) minutes. Infarct-related artery (IRA) was the left anterior descending artery in 47.1%, multivessel disease was present in 49.7%. Primary PCI involved balloon dilatation (2.7%) and stent implantation (97.3%). The incidence of postprocedural angiographic no-reflow was 6.7%. All-cause mortality occurred in 17 patients (3.1%).

CONCLUSION

This study has shown feasibility and efficiency in performing of primary PCI with good outcomes in the first regional interventional center in Bosnia and Herzegovina. Experiences and results of our hospital can be very useful in creating primary PCI networks in our countries and developing countries as well.

Impact of Initial Culprit Vessel Flow on Infarct Size, Microvascular Obstruction, and Myocardial Salvage in Acute Reperfused ST-Elevation Myocardial Infarction

Data on the impact of initial Thrombolysis In Myocardial Infarction (TIMI) flow in the culprit coronary artery on myocardial damage after ST-elevation myocardial infarction (STEMI) are limited. Aim of this multicenter study was, therefore, to elucidate the impact of TIMI flow grade before percutaneous coronary intervention (PCI) on infarct size (IS), myocardial salvage index (MSI), and microvascular obstruction (MVO) assessed by cardiac magnetic resonance (CMR) imaging in patients with STEMI. We enrolled 738 patients with STEMI reperfused by primary PCI within 12 hours after symptom onset at 8 centers. Impaired coronary flow was defined as an initial coronary TIMI flow grade ≤1, whereas preserved coronary flow was defined as an initial coronary TIMI flow grade ≥2. CMR was performed in median 3 days (interquartile range 2 to 4 days) after infarction using a standardized infarction protocol. IS, MVO, and MSI were determined in central core laboratory-masked analyses. The primary clinical end point of the study was the time to major adverse cardiac events defined as death, reinfarction, and new onset of heart failure within 12 months after infarction. TIMI flow ≤1 before PCI was present in 507 patients (68.7%) and was significantly associated with larger IS (19% left ventricular [LV] vs 9% LV; p <0.001), less MSI (0.46 vs 0.65; p <0.001), reduced left ventricular ejection fraction (49% vs 55%; p <0.001), and a higher extent of MVO (0.6% LV vs 0.0% LV; p <0.001). Moreover, TIMI flow before PCI was identified as an independent predictor of IS, MVO, and MSI. However, there were no significant differences in major adverse cardiac event rates between groups (6.1% vs 7.5%; p = 0.48). In conclusion, TIMI flow pre-PCI is reversely associated with myocardial injury and is an independent predictor of myocardial damage assessed by CMR.

Antithrombotic therapy before, during and after emergency angioplasty for ST elevation myocardial infarction

The first three hours after symptom onset hold the maximum potential for myocardial reperfusion and salvage in ST-elevation myocardial infarction (STEMI) patients. During this period timely primary percutaneous coronary intervention (PPCI) or, when PPCI is not promptly feasible, pre-hospital administration of fibrinolyis or a glycoprotein IIb/IIIa-inhibitor (GPI) have been shown to restore coronary patency and reperfusion and even result in myocardial infarction (MI) abortion. On the other hand, oral antiplatelet therapy may not yet guarantee sufficient platelet inhibition. Patients presenting after this golden time have less, if any, benefit from an aggressive antithrombotic treatment prior to PPCI. Antithrombotic treatment during primary angioplasty should be tailored on the basis of the coronary thrombotic burden, vascular approach and the patient's risk of bleeding complications. A GPI-based approach may be favourable in patients presenting early with large MI and high thrombus burden, whereas a bivalirudin-based approach without GPI may be preferred in patients with higher bleeding risk. There are no data to support the use of GPI in bailout conditions. The powerful oral P2Y₁₂ inhibitors, prasugrel and ticagrelor, have been clearly shown to prevent stent thrombosis and recurrent ischaemic events after emergency percutaneous coronary intervention in STEMI patients. Open issues remaining are the treatment of patients with high bleeding risk, such as the elderly and those requiring anticoagulation, as well as the duration of dual antiplatelet therapy after STEMI.

Distance-related Differences in Critical Times, Protocol Activation and Mortality in a Regional STEMI Network

Introduction: The aim of the study was to assess the differences in critical network times and mortality in STEMI patients presenting to hospitals in the same STEMI network, but located at different distances from the pPCI center.

Methods: Four-hundreed sixteen patients with STEMI were studied. Group 1: 101 patients presenting to any of the six regional hospitals in the network located at less than 70 km from the pPCI center, with a maximum transport time of 30 minutes. Group 2: 81 patients presenting to any of the three territorial hospitals in the network located at 70–150 km from the pPCI center, with a transport time between 30 and 70 minutes. Group 3: 93 patients presenting to any of the four territorial hospitals in the network located at 150–250 km from the pPCI center, with a transport time between 70 and 150 minutes. Group 4: 141 patients presenting directly to the emergency room of the pPCI center. The following time intervals were recorded: presentation time (PT), from the onset of symptoms to arrival at the pPCI center; protocol initiation time (PIT), from arrival at the pPCI center to STEMI protocol initiation; ischemic time (IT), from the onset of symptoms to repermeabilisation; door to balloon time (DTB), from arrival in the pPCI center to balloon.

Results: PT showed no significant difference between the groups – 183.08 ± 25.2 minutes vs. 199.1 ± 32.4 minutes vs. 166.7 ± 42.5 minutes vs. 161.91 ± 36.8 minutes, respectively (p=0.4). PIT was significantly lower in Group 3 (61.66 ± 15.4 minutes in Group 3 vs. 92 ± 11.5 minutes in Group 2 vs. 107.4 ± 12.5 minutes in Group 1, p = 0.002). DTB time was significantly longer for patients presenting directly to the pPCI center compared to those arriving from Zone 1, 2 or 3 hospitals, 86.96 ± 11.6 minutes vs. 52.27 ± 11.2 minutes vs. 39.94 ± 10.3 minutes vs. 43.9 ± 5.3 minutes, p <0.001). Despite the differences in distance to the pPCI center, there was no significant difference in total IT between the groups (Group 1, 344.6 ± 53.4 minutes; Group 2, 369.3 ± 42.6 minutes; Group 3, 366.65 ± 36.4 minutes; and 340.2 ± 26.9 minutes in the pPCIcenter, p = 0.2), and this was reflected in similar rates of mortality (Group 1, 3.9%; Group 2, 3.7%; Group 3, 3.2%; and 3.5% in the pPCI center).

Conclusion: A well organized STEMI network can shorten protocol initiation and DTB times, achieving similar ischemic times and resulting in similar mortality rates with the centers located closer to the pPCI center. Early activation of the STEMI protocol could lead to superior results even in areas situated at longer distances from the pPCI center.

In-Hospital Tele-ECG Triage and Interventional Cardiologist Activation of the Infarct Team for STEMI Patients is Associated with Improved Late Clinical Outcomes

BACKGROUND

Due to recent advances, door-to-balloon time (D2BT) has been reduced significantly for patients with ST-segment elevation myocardial infarction (STEMI). However, whether this reduction can be translated into a concrete mortality or morbidity benefit is still the subject of controversy. We conducted a before-and-after study to determine the impact of in-hospital tele-electrocardiography (ECG) triage and interventional cardiologist activation of the infarct team on D2BT and long-term clinical outcomes in STEMI patients undergoing primary percutaneous coronary intervention (PPCI).

METHODS

A total of 272 consecutive patients with acute STEMI undergoing PPCI were enrolled in our study, comprising 102 tele-ECG patients and 170 conventional triage patients. Major adverse cardiovascular and cerebral vascular events (MACCE), including death, recurrent nonfatal MI, nonfatal stroke, and angina-driven target vessel revascularization were recorded during a 3-year follow-up.

RESULTS

The median D2BT of the tele-ECG group was significantly shorter than control group (79 minutes vs. 109 minutes, p < 0.001). The tele-ECG triage group had a higher percentage of patients reaching the D2BT goal (< 90 minutes) (78% vs. 55%; p < 0.001). The MACCE rate was significantly lower in the Tele-ECG versus the control group (23.5% vs. 38.2%, p = 0.012). Tele-ECG group had a lower mortality rate which did not reached statistical significance (2% vs. 5.9%, p = 0.102). In multivariable Cox proportional hazards analyses, the implementation of tele-ECG triage (HR = 0.43, p = 0.003) and the presence of moderate or severe mitral regurgitation at presentation (HR = 1.87, p = 0.029) were discovered as independently associated with MACCE.

CONCLUSIONS

In-hospital tele-ECG triage and interventional cardiologist activation can shorten D2BT and is associated with improved late clinical outcomes during a 3-year follow-up in STEMI patients undergoing PPCI.

Myocardial salvage and mortality in STEMI: A race against ischemic time

Total ischemic time (IT) and door-to-balloon time (DBT) are two important measures in patients with ST segment elevation myocardial infarction (STEMI). IT is a better predictor of cardiovascular outcomes than DTB, including infarct size and mortality, in STEMI patients treated with primary percutaneous coronary intervention. IT should be adopted as a standard metric to measure quality of care in STEMI, and will help to promote improvements to our health care delivery system.

Comparison of 30-day mortality and myocardial scar indices for patients treated with prehospital reduced dose fibrinolytic followed by percutaneous coronary intervention versus percutaneous coronary intervention alone for treatment of ST-elevation myocardial infarction

OBJECTIVES

We investigated whether prehospital, reduced dose fibrinolysis coupled with urgent percutaneous coronary intervention (FAST-PCI) reduces mortality and cardiac magnetic resonance (CMR) measures of infarct size, compared with primary percutaneous coronary intervention (PPCI), in patients with ST-elevation myocardial infarction (STEMI).

BACKGROUND

Current standard therapy for STEMI is PPCI. However, FAST-PCI may shorten ischemic time (IT) and improve outcomes.

METHODS

Eligible STEMI patients received prehospital, reduced dose fibrinolysis along with standard therapy, and were transported for urgent percutaneous coronary intervention, or else they received usual treatment without prehospital fibrinolysis. Patients were divided retrospectively into four groups based on IT (<120, 120-179, 180-239 min, ≥240) for a mortality analysis cohort, and into three groups (<120, 120-179, ≥180 min) for a CMR analysis cohort. Within each IT group, patients were compared by FAST-PCI vs. PPCI strategy.

RESULTS

Between 1/2007 and 2/2014, 1,112 STEMI patients were treated. FAST-PCI was employed in 551 and PPCI in 561. Of these, 357 (32.1%) underwent CMR. The treatment groups were well matched. In STEMI patients with short IT (<120 and 120-179 min groups), those treated by FAST-PCI had lower 30-day mortality and myocardial scar sizes compared with PPCI treatment. For IT ≥180 min, the mortalities and myocardial scar sizes were equivalent for both groups.

CONCLUSIONS

In STEMI patients with IT <180 min, FAST-PCI may reduce 30-day mortality and myocardial scar size compared with PPCI. This suggests that infarct interventions must be instituted within 3 hr of symptom onset in order to detect an optimal beneficial effect both clinically and by CMR measurement. © 2016 Wiley Periodicals, Inc.

Pre-hospital electrocardiographic severity and acuteness scores predict left ventricular function in patients with ST elevation myocardial infarction

OBJECTIVES

System delay (time from first medical contact to primary percutaneous coronary intervention) is associated with heart failure and mortality in patients with ST segment elevation myocardial infarction (STEMI). We evaluated the impact of system delay on left ventricular function (LVF) according to the combination of ischemia severity (Sclarovsky-Birnbaum grades) and acuteness (Anderson-Wilkins scores) in the pre-hospital electrocardiogram (ECG).

METHODS

In a predefined secondary analysis of a prospective study, the severity and acuteness scores were performed on the pre-hospital ECG. Patients were assessed with respect to 4 classifications which were not mutually exclusive: severe ischemia (+SI) or non-severe ischemia (-SI) and acute ischemia (+AI) or non-acute ischemia (-AI). LVF was assessed by global longitudinal strain (GLS) within 48hours of admission. Adjusted linear regression investigated the association of system delay with GLS in each group.

RESULTS

In total 262 patients were eligible for analysis of the ECG, which resulted in 42 (16%) with (+SI, -AI), 110 (42%) with (-SI, -AI), 90 (34%) with (-SI, +AI), and 20 (8%) patients with (+SI, +AI). Although system delay did not differ between groups, patients with severe and non-acute ischemia had the most impaired LVF. System delay correlated weakly with GLS in the entire population (r=0.133, p=0.031), and well with GLS in the (+SI, +AI) group (r=0.456, p=0.04), while there was no correlation in the other groups. By adjusted analysis, system delay predicted impaired GLS only in the (+SI, +AI) group (β=0.578, p=0.002).

CONCLUSION

Pre-hospital risk stratification by ECG identifies patients with acute and severe ischemia who are at increased risk for reduced ventricular function (assessed by GLS) after STEMI. Optimizing reperfusion delays in these patients can therefore be of particular benefit in improving clinical outcome after STEMI.

Predictors, treatment, and outcomes of STEMI occurring in hospitalized patients

ST-segment elevation myocardial infarction (STEMI) is most commonly caused by an acute thrombotic occlusion of a coronary artery. For patients in whom the onset of STEMI occurs outside of hospital (outpatient STEMI), early reperfusion therapy with either fibrinolysis or primary percutaneous coronary intervention reduces complications and improves survival, compared with delayed reperfusion. STEMI systems of care are defined as integrated groups of separate entities focused on reperfusion therapy for STEMI, generally including emergency medical services, emergency medicine, cardiology, nursing, and hospital administration. These systems of care have been successful at reducing total ischaemia time and outpatient STEMI mortality. By contrast, much less is known about STEMI that occurs in hospitalized patients (inpatient STEMI), which has unique clinical features and much worse outcomes than outpatient STEMI. Inpatient STEMI is associated with older age, a higher female:male ratio, and more comorbidities than outpatient STEMI. Delays in diagnosis and infrequent use of reperfusion therapy probably also contribute to unfavourable outcomes for inpatient STEMI.

No-Reflow Phoenomenon by Intracoronary Thrombus in Acute Myocardial Infarction

Recently, percutaneous coronary intervention has been the treatment of choice in most acute myocardial infarction cases. Although the results of percutaneous coronary interventions have ben good, the no-reflow phenomenon and distal embolization of intracoronary thrombus are still major problems even after successful interventions. In this article, we will briefly review the deleterious effects of no-reflow and distal embolization of intracoronary thrombus during percutaneous coronary interventions. The current trials focused on the prevention and treatment of the no-reflow phenomenon and intracoronary thrombus.

Microvascular Obstruction Evaluation Using Cardiovascular Magnetic Resonance (CMR) in ST-Elevated Myocardial Infarction (STEMI) Patients

BACKROUND

Restoration of blood flow in epicardial coronary artery in patients with acute myocardial infarction can, but does not have to restore efficient blood flow in coronary circulation. The aim of the study was a direct comparison of microvascular obstruction (MVO) detected by rest and stress perfusion imaging and gadolinium enhancement obtained 2 min. (early MVO) and 15 min. (delayed MVO) post contrast.

MATERIAL/METHODS

106 patients with first anterior myocardial infarction were studied. Cardiovascular magnetic resonance (CMR) was performed 5±2 days after primary percutaneous coronary intervention (pPCI). Stress and rest perfusion imaging was performed as well as early and delayed gadolinium enhancement and systolic function assessment. Scoring of segmental function, perfusion defect, MVO and scar transmurality was performed in 16 segment left ventricular model.

RESULTS

The prevalence of MVO varies significantly between imaging techniques ranging from 48.8% for delayed MVO to 94% with stress perfusion. Median sum of scores was significantly different for each technique: stress perfusion 13 (7; 18), rest perfusion 3 (0.5; 6), early MVO 3 (0; 8), delayed MVO 0 (0; 4); p<0.05. Infarct size, stress and rest perfusion defects were independent predictors of LV EF at discharge from hospital.

CONCLUSIONS

Imaging protocol has a significant impact on MVO results. The study is the first to describe a stress-induced MVO in STEMI patients. Further research is needed to evaluate its impact on a long term prognosis.