Therapeutic Hypothermia and Stent Thrombosis: A Nationwide Analysis

Therapeutic hypothermia in patients with acute myocardial infarction complicated by out-of-hospital cardiac arrest

BACKGROUND

There is a lack of data regarding outcomes of therapeutic hypothermia in patients with acute myocardial infarction (AMI) complicated by out-of-hospital cardiac arrest (OHCA). This study aimed to evaluate the effect of therapeutic hypothermia on clinical outcomes in comatose patients after percutaneous coronary intervention (PCI) for AMI following OHCA.

METHODS

Using a prospective nationwide registry from 2016 to 2021, we selected 2925 patients with AMI who underwent emergency PCI among 182,508 OHCA cases. These patients were divided into groups receiving hypothermia treatment (n = 624) and those not receiving hypothermia treatment (n = 2301). The primary endpoint was in-hospital mortality, and secondary endpoints were mortality rate at 24 h and neurological outcomes at discharge.

RESULTS

The hypothermia group showed a significantly lower rate of in-hospital mortality than the non-hypothermia group (odds ratio [OR] 0.71; 95% confidence interval [CI], 0.59-0.85; P < 0.001). However, there was no significant difference in neurological outcomes at discharge between the two groups. Furthermore, quartile analysis of door-to-cooling (DtC) time, defined as the time from hospital arrival to initiation of hypothermia, demonstrated that a shorter DtC time was associated with a decreased risk of mortality and poor neurological outcomes (mortality: adjusted OR, 0.40; 95% CI, 0.30-0.54; P < 0.001; poor neurological outcome: adjusted OR, 0.59; 95% CI, 0.45-0.77; P < 0.001 for quartile 1 versus quartile 4).

CONCLUSIONS

Therapeutic hypothermia reduced the rate of in-hospital mortality in patients with AMI complicated by OHCA. Moreover, early initiation of hypothermia demonstrated a reduction in mortality and poor neurological outcomes.

PRE-REGISTERED CLINICAL TRIAL NUMBER

URL: http://clinicaltrials.gov . Unique identifier: NCT05724914. In this large, government-controlled, nationwide, prospective real-world registry with AMI and complicated by OHCA, we demonstrated therapeutic hypothermia reduced the rate of in-hospital mortality, but it did not improve neurological outcomes at discharge. Our findings also showed that early initiation of hypothermia was significantly associated with reduced in-hospital mortality and poor neurological outcomes. The findings of this study suggest that therapeutic hypothermia reduces in-hospital mortality in patients with AMI complicated by OHCA. Early application of hypothermia should be considered as a potential means of improving neurological outcomes in patients with AMI-OHCA undergoing emergency PCI.

Cardiac Catheterization Laboratory Management of the Comatose Adult Patient With an Out-of-Hospital Cardiac Arrest: A Scientific Statement From the American Heart Association

Out-of-hospital cardiac arrest is a leading cause of death, accounting for ≈50% of all cardiovascular deaths. The prognosis of such individuals is poor, with <10% surviving to hospital discharge. Survival with a favorable neurologic outcome is highest among individuals who present with a witnessed shockable rhythm, received bystander cardiopulmonary resuscitation, achieve return of spontaneous circulation within 15 minutes of arrest, and have evidence of ST-segment elevation on initial ECG after return of spontaneous circulation. The cardiac catheterization laboratory plays an important role in the coordinated Chain of Survival for patients with out-of-hospital cardiac arrest. The catheterization laboratory can be used to provide diagnostic, therapeutic, and resuscitative support after sudden cardiac arrest from many different cardiac causes, but it has a unique importance in the treatment of cardiac arrest resulting from underlying coronary artery disease. Over the past few years, numerous trials have clarified the role of the cardiac catheterization laboratory in the management of resuscitated patients or those with ongoing cardiac arrest. This scientific statement provides an update on the contemporary approach to managing resuscitated patients or those with ongoing cardiac arrest.

Optimal Antithrombotic Strategies in Cardiogenic Shock

Cardiogenic shock (CS) represents a critical condition with a high mortality rate. The most common cause of CS is coronary artery disease, and patients typically present with myocardial infarction, necessitating immediate treatment through percutaneous coronary intervention (PCI) and often requiring mechanical circulatory support. CS is associated with a prothrombotic situation, while on the other hand, there is often a significant risk of bleeding. This dual challenge complicates the selection of an optimal antithrombotic strategy. The choice of antithrombotic agents must be personalized, taking into consideration all relevant conditions. Repeated risk assessment, therapeutic monitoring, and adjusting antithrombotic therapy are mandatory in these patients. This review article aims to provide an overview of the current evidence and practical guidance on antithrombotic strategies in the context of CS.

Balancing thrombosis and bleeding after out-of-hospital cardiac arrest related to acute coronary syndrome: A literature review

Balance between thrombosis and bleeding is now well recognized in patients treated for acute coronary syndrome, with impact on short- and long-term prognosis, including survival. Recent data suggest that patients who are resuscitated after out-of-hospital cardiac arrest related to myocardial infarction are at an even higher risk of bleeding and thrombosis than those with uncomplicated acute coronary syndrome. Delayed enteral absorption of medication due to induced hypothermia and systemic inflammation increases thrombosis risk, whereas transfemoral access site, cardiopulmonary resuscitation manoeuvres and mechanical circulatory support devices increase bleeding risk. In addition, post-resuscitation syndrome and renal or hepatic impairment are potential risk factors for both bleeding and thrombotic complications. There are currently no randomized controlled trials comparing various P₂Y₁₂ inhibitor and/or anticoagulation strategies in the setting of out-of-hospital cardiac arrest, and current practice is largely derived from management of patients with uncomplicated acute coronary syndrome. The aim of this review is therefore to describe the bleeding and thrombosis risk factors in this specific population, and to review recent data on antithrombotic drugs in this patient subset.

ST-Elevation Myocardial Infarction Complicated by Out-of-Hospital Cardiac Arrest

5-10% of ST-elevated myocardial infarctions (STEMI) present with out-of-hospital cardiac arrest (OHCA). Although this subgroup of patients carries the highest in-hospital mortality among the STEMI population, it is the least likely to undergo coronary angiography and revascularization. Due to the concomitant neurologic injury, patients with OHCA STEMI require prolonged hospitalization and adjustments to standard MI management. This review systematically assesses the course of patients with OHCA STEMI from development of the arrest to hospital discharge, assesses the limiting factors for their treatment access, and presents the evidence-based optimal intervention strategy for this high-risk MI population.

Hypothermia in patients with acute myocardial infarction: a meta-analysis of randomized trials

BACKGROUND

In patients with acute myocardial infarction (MI) receiving percutaneous coronary intervention (PCI), the role of systemic therapeutic hypothermia remains controversial. We sought to investigate the role of systemic therapeutic hypothermia versus standard of care in patients with acute MI treated with PCI.

METHODS

This is a study-level meta-analysis of randomized trials. The primary outcome was all-cause death. The main secondary outcome was infarct size. Other secondary outcomes were recurrent MI, ischemia-driven target vessel revascularization (TVR), major adverse cardiovascular events, and bleeding.

RESULTS

A total of 1012 patients with acute MI receiving a PCI in nine trials (503 randomly assigned to hypothermia and 509 to control) were available for the quantitative synthesis. The weighted median follow-up was 30 days. As compared to controls, patients assigned to hypothermia had similar risk of all-cause death (risk ratio, [95% confidence intervals], 1.25 [0.80; 1.95], p = 0.32), with a trend toward higher risk of ischemia-driven TVR (3.55 [0.80; 15.87], p = 0.09) mostly due to acute or subacute stent thrombosis. Although in the overall cohort, infarct size was comparable between groups (standardized mean difference [95% Confidence intervals], 0.06 [- 0.92; 1.04], p = 0.92), patients effectively achieving the protocol-defined target temperature in the hypothermia group had smaller infarct size as compared to controls (p for interaction = 0.016). Treatment strategies did not differ with respect to the other outcomes.

CONCLUSIONS

As compared to standard of care, systemic therapeutic hypothermia in acute MI patients treated with PCI provided similar mortality with a signal toward more frequent repeat revascularization. Among patients assigned to hypothermia, those effectively achieving the protocol-defined target temperature displayed smaller infarct size.

TRIAL REGISTRATION

PROSPERO, CRD42019138754.

Antithrombotic therapy in patients with acute coronary syndrome complicated by cardiogenic shock or out-of-hospital cardiac arrest: a joint position paper from the European Society of Cardiology (ESC) Working Group on Thrombosis, in association with the Acute Cardiovascular Care Association (ACCA) and European Association of Percutaneous Cardiovascular Interventions (EAPCI)

Timely and effective antithrombotic therapy is critical to improving outcome, including survival, in patients with acute coronary syndrome (ACS). Achieving effective platelet inhibition and anticoagulation, with minimal risk, is particularly important in high-risk ACS patients, especially those with cardiogenic shock (CS) or those successfully resuscitated following out-of-hospital cardiac arrest (OHCA), who have a 30-50% risk of death or a recurrent ischaemic event over the subsequent 30 days. There are unique challenges to achieving effective and safe antithrombotic treatment in this cohort of patients that are not encountered in most other ACS patients. This position paper focuses on patients presenting with CS or immediately post-OHCA, of presumed ischaemic aetiology, and examines issues related to thrombosis and bleeding risk. Both the physical and pharmacological impacts of CS, namely impaired drug absorption, metabolism, altered distribution and/or excretion, associated multiorgan failure, co-morbidities and co-administered treatments such as opiates, targeted temperature management, renal replacement therapy and circulatory or left ventricular assist devices, can have major impact on the effectiveness and safety of antithrombotic drugs. Careful attention to the choice of antithrombotic agent(s), route of administration, drug-drug interactions, therapeutic drug monitoring and factors that affect drug efficacy and safety, may reduce the risk of sub- or supra-therapeutic dosing and associated adverse events. This paper provides expert opinion, based on best available evidence, and consensus statements on optimising antithrombotic therapy in these very high-risk patients, in whom minimising the risk of thrombosis and bleeding is critical to improving outcome.

Moderate Hypothermia Modifies Coronary Hemodynamics and Endothelium-Dependent Vasodilation in a Porcine Model of Temperature Management

Background Hypothermia has been associated with therapeutic benefits including reduced mortality and better neurologic outcomes in survivors of cardiac arrest. However, undesirable side effects have been reported in patients undergoing coronary interventions. Using a large animal model of temperature management, we aimed to describe how temperature interferes with the coronary vasculature. Methods and Results Coronary hemodynamics and endothelial function were studied in 12 pigs at various core temperatures. Left circumflex coronary artery was challenged with intracoronary nitroglycerin, bradykinin, and adenosine at normothermia (38°C) and mild hypothermia (34°C), followed by either rewarming (38°C; n=6) or moderate hypothermia (MoHT; 32°C, n=6). Invasive coronary hemodynamics by Doppler wire revealed a slower coronary blood velocity at 32°C in the MoHT protocol (normothermia 20.2±11.2 cm/s versus mild hypothermia 18.7±4.3 cm/s versus MoHT 11.3±5.3 cm/s, P=0.007). MoHT time point was also associated with high values of hyperemic microvascular resistance (>3 mm Hg/cm per second) (normothermia 2.0±0.6 mm Hg/cm per second versus mild hypothermia 2.0±0.8 mm Hg/cm per second versus MoHT 3.4±1.6 mm Hg/cm per second, P=0.273). Assessment of coronary vasodilation by quantitative coronary analysis showed increased endothelium-dependent (bradykinin) vasodilation at 32°C when compared with normothermia (normothermia 6.96% change versus mild hypothermia 9.01% change versus MoHT 25.42% change, P=0.044). Results from coronary reactivity in vitro were in agreement with angiography data and established that endothelium-dependent relaxation in MoHT completely relies on NO production. Conclusions In this porcine model of temperature management, 34°C hypothermia and rewarming (38°C) did not affect coronary hemodynamics or endothelial function. However, 32°C hypothermia altered coronary vasculature physiology by slowing coronary blood flow, increasing microvascular resistance, and exacerbating endothelium-dependent vasodilatory response.

Acute and sub-acute stent thrombosis: Frequency, predictors and features in patients undergoing primary percutaneous intervention at a tertiary care cardiac centre

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Early stent thrombosis (ST) is relatively frequent in patients undergoing primary PCI.

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Diabetic and hypertensive patients are at an increased risk of ST.

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Presentation of patients in Killip Class III-IV is an independent predictor of early ST.

Objectives

To assess the frequency of early (acute and sub-acute) stent thrombosis (ST) after primary percutaneous coronary intervention (pPCI) and to identify its potential predictors.

Background

ST is a serious clinical event associated with a high mortality rate. A very limited data are available regarding the incidence rate of early ST after pPCI and its predictors, especially for Pakistani population.

Methods

Study included consecutive patients who underwent primary PCI. Telephonic follow-ups were made to obtain 30-days outcomes including ST, mortality, and re-occurrence of symptoms. ST was defined as per the standardized definition proposed by the Academic Research Consortium and classified as acute (during the procedure) and sub-acute (within 30 days).

Results

A total of 569 patients were included with 80.5% (485) male patients. The stent thrombosis (acute or sub-acute) was observed in 33 (5.8%) patients out of which 3 (9.1%) were definite ST while remaining 30 (90.9%) were probable ST. Patients who develop ST were predominantly male, hypertensive, diabetic, with reduced pre PCI LVEF (%) and Killip Class. A significantly higher in-hospital mortality rate was observed in patients with ST as compared to without ST, 36.4% (12/33) vs. 0.2% (1/536); p-value < 0.001 respectively. Killip Class (III-IV) was found to be the independent predictor of ST with an adjusted odds ratio of 5.2 [1.76–15.32].

Conclusions

Early stent thrombosis (ST) is relatively frequent in patients undergoing primary PCI. Diabetic and hypertensive patients are at an increased risk of ST and presentation of patients in Killip Class III-IV is an independent predictor of early ST.

A pilot clinical study of adjunctive therapy with selective intracoronary hypothermia in patients with ST-segment elevation myocardial infarction

OBJECTIVES

We aimed to assess the effect of selective intracoronary hypothermia on outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

BACKGROUND

Intracoronary hypothermia, the feasibility and safety of which has been validated in humans, induced by selective trans-coronary infusion of saline at different temperatures can reduce infarct size (IS) prior to reperfusion in animal models of STEMI.

METHODS

Sixty STEMI patients presenting with thrombolysis in myocardial infarction (TIMI) flow grade 0/1 were randomized after coronary artery angiography. Intracoronary hypothermia was induced by selective trans-coronary infusion of saline at 4°C to the endangered myocardium in the 30 patients. The primary endpoint, absolute IS expressed as IS/myocardium at risk (MaR), was assessed by cardiac magnetic resonance imaging at day 7 post-PPCI in 50 patients. Clinical follow-up was undertaken at day 30 after procedure.

RESULTS

Intracoronary hypothermia was successfully performed in hypothermia group, without increase in arrhythmia or hemodynamic instability. The mean temperature reduction of 5.8 ± 1.1°C in distal coronary artery was achieved before reperfusion. Mean IS/MaR was predominantly reduced in the hypothermia group (44.85 ± 5.89% vs. 50.69 ± 10.75%, P = 0.022), especially in the anterior STEMI subgroup (46.12 ± 7.54% vs. 55.27 ± 11.175%, P = 0.023). The clinical events appeared no statistical difference between the two groups at the 30-day follow-up.

CONCLUSION

The statistical difference in IS/MaR by intracoronary hypothermia as adjunctive therapy to PPCI is an important observation and warrants a larger pivotal trial fully powered for efficacy.

Use of therapeutic hypothermia among patients with coagulation disorders - A Nationwide analysis

OBJECTIVES

The study aimed to assess the impact of therapeutic hypothermia (TH) on bleeding and in-hospital mortality among patients with coagulation disorders (CD).

BACKGROUND

TH affects coagulation factors and platelets putting patients at risk for bleeding and worse outcomes. Effect of TH among patients with CD remains understudied.

METHODS

Between 2009 and 2014, a total of 6469 cases of TH were identified using the National Inpatient Sample out of which 1036 (16.02%) had a CD. The incidence of bleeding events, blood product transfusion and in-hospital mortality was compared between patients with and without CD using one to one propensity score matching.

RESULTS

Proportion of patients with CD increased during study duration from 13.0% to 17.4% from 2009 to 2014. Propensity matching was performed to adjust for baseline differences with 799 patients in both groups depending on presence or absence of CD. Patients with CD had a higher rate of bleeding events (13% vs. 8.5%; adjusted odds ratio 1.60; 95% confidence interval 1.16-2.23; P = 0.004), and blood product transfusion (25.0% vs. 14.1%; aOR 2.03; 95% CI 1.56-2.63; p < 0.001) compared to those without CD. There was no difference in rate of intracranial bleeding or hemorrhagic strokes between those with and without CD (3.3% vs. 3.2%; p = 0.88). There was no difference in mortality between patients with CD and those without (74.5% vs. 74.8%, aOR 0.98, 95% CI 0.78-1.23; P = 0.86).

CONCLUSIONS

Use of TH with CD resulted in more bleeding events and blood product transfusion but there was no difference in hospital mortality.

Erythropoietin therapy after out-of-hospital cardiac arrest: A systematic review and meta-analysis

AIM

To assess safety and efficacy of early erythropoietin (Epo) administration in patients with out-of-hospital cardiac arrest (OHCA).

METHODS

A systematic literature search was performed using PubMed, MEDLINE, EMBASE, EBSCO, CINAHL, Web of Science and Cochrane databases, of all studies published from the inception through October 10, 2016. Inclusion criteria included: (1) Adult humans with OHCA and successful sustained return of spontaneous circulation; and (2) studies including mortality/brain death, acute thrombotic events as their end points. Primary efficacy outcome was “brain death or Cerebral Performance Category (CPC) score of 5”. Secondary outcomes were “CPC score 1, and 2-4”, “overall thrombotic events” and “acute coronary stent thrombosis”.

RESULTS

We analyzed a total of 606 participants (n = 276 received Epo and n = 330 with standard of care alone) who experienced OHCA enrolled in 3 clinical trials. No significant difference was observed between the Epo and no Epo group in brain death or CPC score 5 (OR = 0.77; 95%CI: 0.42-1.39), CPC score 1 (OR = 1.16, 95%CI: 0.82-1.64), and CPC score 2-4 (OR = 0.77, 95%CI: 0.44-1.36). Epo group was associated with increased thrombotic complications (OR = 2.41, 95%CI: 1.26-4.62) and acute coronary stent thrombosis (OR = 8.16, 95%CI: 1.39-47.99). No publication bias was observed.

CONCLUSION

Our study demonstrates no improvement in neurological outcomes and increased incidence of thrombotic events and acute coronary stent thrombosis in OHCA patients who were treated with Epo in addition to standard therapy.

Sudden cardiac death

INTRODUCTION

Sudden cardiac arrest continues to be the leading cause of death in the industrialized world.

SOURCES OF DATA

Original papers, reviews and guidelines.

AREAS OF AGREEMENT

Community programs for lay bystander cardiopulmonary resuscitation (CPR) and automatic external defibrillation improve outcomes. Post-arrest care, including targeted temperature management (TTM) combined with early coronary angiography and percutaneous coronary intervention, is helpful for those suffering cardiac arrest during an ST-segment elevation myocardial infarction.

AREAS OF CONTROVERSY

(1) The optimal approach to encourage lay bystanders to assist with resuscitation efforts. (2) Whether TTM combined with early coronary angiography is cost effective for those without ST elevation on their post-arrest ECG is unknown.

GROWING POINTS

Increasing data show that chest compression-only CPR is preferred by lay rescuers and improves local survival rates.

AREAS TIMELY FOR DEVELOPING RESEARCH

Randomized clinical trials are underway to examine the utility of early coronary angiography in the treatment of post-arrest patients without ST-segment elevation.

Intensive care medicine research agenda on cardiac arrest

Over the last 15 years, treatment of comatose post-cardiac arrest patients has evolved to include therapeutic strategies such as urgent coronary angiography with percutaneous coronary intervention (PCI), targeted temperature management (TTM)-requiring mechanical ventilation and sedation-and more sophisticated and cautious prognostication. In 2015, collaboration between the European Resuscitation Council (ERC) and the European Society for Intensive Care Medicine (ESICM) resulted in the first European guidelines on post-resuscitation care. This review addresses the major recent advances in the treatment of cardiac arrest, recent trials that have challenged current practice and the remaining areas of uncertainty.

New Developments in the Treatment of Acute Myocardial Infarction Associated with Out-of-Hospital Cardiac Arrest. A Review

Out-of-hospital cardiac arrest (OHCA) occurring as the first manifestation of an acute myocardial infarction is associated with very high mortality rates. As in comatose patients the etiology of cardiac arrest may be unclear, especially in cases without ST-segment elevation on the surface electrocardiogram, the decision to perform or not to perform urgent coronary angiography can have a significant impact on the prognosis of these patients. This review summarises the current knowledge and recommendations for treating patients with acute myocardial infarction presenting with OHCA. New therapeutic measures for the post-resuscitation phase are presented, such as hypothermia or extracardiac life support, together with strategies aiming to restore the coronary flow in the resuscitation phase using intra-arrest percutaneous revascularization performed during resuscitation. The role of regional networks in providing rapid access to the hospital facilities and to a catheterization laboratory for these critical cardiovascular emergencies is described.