Faster Hypothermia Induced by Esophageal Cooling Improves Early Markers of Cardiac and Neurological Injury After Cardiac Arrest in Swine

Changing epidemiology of congenital heart disease: effect on outcomes and quality of care in adults

The epidemiology of congenital heart disease (CHD) has changed in the past 50 years as a result of an increase in the prevalence and survival rate of CHD. In particular, mortality in patients with CHD has changed dramatically since the latter half of the twentieth century as a result of more timely diagnosis and the development of interventions for CHD that have prolonged life. As patients with CHD age, the disease burden shifts away from the heart and towards acquired cardiovascular and systemic complications. The societal costs of CHD are high, not just in terms of health-care utilization but also with regards to quality of life. Lifespan disease trajectories for populations with a high disease burden that is measured over prolonged time periods are becoming increasingly important to define long-term outcomes that can be improved. Quality improvement initiatives, including advanced physician training for adult CHD in the past 10 years, have begun to improve disease outcomes. As we seek to transform lifespan into healthspan, research efforts need to incorporate big data to allow high-value, patient-centred and artificial intelligence-enabled delivery of care. Such efforts will facilitate improved access to health care in remote areas and inform the horizontal integration of services needed to manage CHD for the prolonged duration of survival among adult patients.

Autonomic modulation of ventricular electrical activity: recent developments and clinical implications

PURPOSE

This review aimed to provide a complete overview of the current stance and recent developments in antiarrhythmic neuromodulatory interventions, focusing on lifethreatening vetricular arrhythmias.

METHODS

Both preclinical studies and clinical studies were assessed to highlight the gaps in knowledge that remain to be answered and the necessary steps required to properly translate these strategies to the clinical setting.

RESULTS

Cardiac autonomic imbalance, characterized by chronic sympathoexcitation and parasympathetic withdrawal, destabilizes cardiac electrophysiology and promotes ventricular arrhythmogenesis. Therefore, neuromodulatory interventions that target the sympatho-vagal imbalance have emerged as promising antiarrhythmic strategies. These strategies are aimed at different parts of the cardiac neuraxis and directly or indirectly restore cardiac autonomic tone. These interventions include pharmacological blockade of sympathetic neurotransmitters and neuropeptides, cardiac sympathetic denervation, thoracic epidural anesthesia, and spinal cord and vagal nerve stimulation.

CONCLUSION

Neuromodulatory strategies have repeatedly been demonstrated to be highly effective and very promising anti-arrhythmic therapies. Nevertheless, there is still much room to gain in our understanding of neurocardiac physiology, refining the current neuromodulatory strategic options and elucidating the chronic effects of many of these strategic options.

Differences in oral anticoagulant prescriptions between specialists and non-specialists in patients with cardioembolic stroke caused by non-valvular atrial fibrillation

Atrial fibrillation (AF) is a common disease encountered in daily practice; however, few patients with AF received oral anticoagulant (OAC) therapy. This study focused on differences in OAC prescriptions and influencing factors between specialists (neurological and cardiovascular) and non-specialists. A retrospective comparative analysis was conducted on 480 patients with acute cardioembolic stroke caused by non-valvular AF who were admitted to our hospital between January 1, 2015, and December 31, 2020. All patients had visited our hospital or other hospitals for their underlying diseases. Overall, 232 (specialist group SG) and 248 patients (non-specialist group NSG) were examined by specialists and non-specialists, respectively. The NSG had a significantly lower percentage of OAC prescriptions on admission than the SG (P < 0.01), even after propensity score matching. Factors influencing OAC prescription in the SG were age, hypertension, paroxysmal AF, dementia, CHADS₂ score, and antiplatelet drug use, while those in the NSG were a history of cerebral infarction, paroxysmal AF, dementia, and antiplatelet drug use [SG: age, odds ratio (OR) 0.919, 95% confidence interval (CI) 0.865-0.976; hypertension, OR 0.266, 95% CI 0.099-0.713; paroxysmal AF, OR 0.189, 95% CI 0.055-0.658; dementia, OR 0.253, 95% CI 0.085-0.758; CHADS₂ score, OR 2.833, 95% CI 1.682-4.942; and antiplatelet drug use, OR 0.072, 95% CI 0.025-0.206; NSG: cerebral infarction, OR 5.940, 95% CI 1.581-22.309; paroxysmal AF, OR 0.077, 95% CI 0.010-0.623; dementia, OR 0.077, 95% CI 0.014-0.438; and antiplatelet drug use, OR 0.024, 95% CI 0.004-0.152]. In conclusion, the OAC prescription rate was higher in patients with non-valvular AF whose family physicians were specialists at the time of cerebral infarction onset. In addition, in the SG, advanced age and hypertension were associated with not prescribing OAC, whereas a higher CHADS₂ score was associated with the prescription of OACs. In the NSG, a history of cerebral infarction was associated with the prescription of OACs. Further, paroxysmal AF, antiplatelet drug use, and dementia were associated with non-OAC therapy in both the groups.

Prognostic value of hepatorenal function following transcatheter edge-to-edge mitral valve repair

BACKGROUND

Hepatorenal dysfunction is a strong prognostic predictor in patients with heart failure. However, the prognostic impact of the hepatorenal dysfunction in patients undergoing transcatheter mitral valve repair (TMVR) has not been well studied.

METHODS

In consecutive patients who underwent edge-to-edge TMVR at three German centers, the model for end-stage liver disease excluding international normalized ratio (MELD-XI) score was calculated as 5.11 × ln [serum total bilirubin (mg/dl)] + 11.76 × ln [serum creatinine (mg/dl)] + 9.44. Patients were stratified into high (> 11) or low (≤ 11) MELD-XI score of which an incidence of the composite outcome, consisting of all-cause mortality and heart failure hospitalization, within 2 years after TMVR was assessed.

RESULTS

Of the 881 patients, the mean MELD-XI score was 11.0 ± 5.9, and 415 patients (47.1%) had high MELD-XI score. The MELD-XI score was correlated with male, effective regurgitant orifice area, and tricuspid regurgitation severity and inversely related to left ventricular ejection fraction. Patients with high MELD-XI score had a higher incidence of the composite outcome than those with low MELD-XI score (47.7% vs. 29.8%; p < 0.0001), and in multivariable analysis, the high MELD-XI score was an independent predictor of the composite outcome [adjusted hazard ratio (HR) 1.34; 95% confidence interval (CI) 1.02-1.77; p = 0.04). Additionally, the MELD-XI score as a continuous variable was also an independent predictor (adjusted HR 1.02; 95% CI 1.00-1.05; p = 0.048).

CONCLUSIONS

The MELD-XI score was associated with clinical outcomes within 2 years after TMVR and can be a useful risk-stratification tool in patients undergoing TMVR.

Fast hypothermia induced by extracorporeal circuit cooling alleviates renal and intestinal injury after cardiac arrest in swine

BACKGROUND

Continuous renal replacement therapy (CRRT) was currently demonstrated to be an effective way to induce fast hypothermia and had proective effects on cardiac dysfunction and brain damage after cardiac pulmonary resuscitation (CPR). In the present study, we aimed to investigate the influence of extracorporeal circuit cooling using CRRT on renal and intestinal damage after CPR based on a porcine model.

METHODS

32 pigs were subjected to ventricular fibrillation for 8 min, followed by CPR for 5 min before defibrillation. All were randomized to receive extracorporeal circuit cooling using CRRT (CRRT, n = 9), surface cooling (SC, n = 9), normothermia (NT, n = 9) or sham control (n = 5) at 5 min post resuscitation. Pigs in the CRRT group were cooled by 8-h CRRT cooling with the infusion line initially submerged in 4 °C of ice water and 16-h SC, while in the SC group by a 24-h SC. Temperatures were maintained at a normal range in the other two groups. Biomarkers in serum were measured at baseline and 1, 3, 6, 12, 24 and 30 h post resuscitation to assess organ functions. Additionally, tissues of kidney and intestine were harvested, from which the degree of tissue inflammation, oxidative stress, and apoptosis levels were analyzed.

RESULTS

The blood temperature decreased faster by extracorporeal circuit cooling using CRRT than SC (9.8 ± 1.6 vs. 1.5 ± 0.4 °C/h, P < 0.01). Post-resuscitation renal and intestinal injury were significantly improved in the 2 hypothermic groups compared to the NT group. And the improvement was significantly greater in animals received extracorporeal circuit cooling than those received surface cooling, from both the results of biomarkers in serum and pathological evidence.

CONCLUSION

Fast hypothermia induced by extracorporeal circuit cooling was superior to. surface cooling in mitigating renal and intestinal injury post resuscitation.

Staying Cool in Space: A Review of Therapeutic Hypothermia and Potential Application for Space Medicine

Despite rigorous health screenings, medical incidents during spaceflight missions cannot be avoided. With long-duration exploration flights on the rise, the likelihood of critical medical conditions with no suitable treatment on board will increase. Therapeutic hypothermia (TH) could serve as a bridge treatment in space prolonging survival and reducing neurological damage in ischemic conditions such as stroke and cardiac arrest. We conducted a review of published studies to determine the potential and challenges of TH in space based on its physiological effects, the cooling methods available, and clinical evidence on Earth. Currently, investigators have found that application of low normothermia leads to better outcomes than mild hypothermia. Data on the impact of hypothermia on a favorable neurological outcome are inconclusive due to lack of standardized protocols across hospitals and the heterogeneity of medical conditions. Adverse effects with systemic cooling are widely reported, and could be reduced through selective brain cooling and pharmacological cooling, promising techniques that currently lack clinical evidence. We hypothesize that TH has the potential for application as supportive treatment for multiple medical conditions in space and recommend further investigation of the concept in feasibility studies.

Investigation of myocardial protection during pediatric CPB: Practical experience in 100 Chinese hospitals

Many measures have been proposed for myocardial protection in pediatric congenital heart surgeries, but little data is available for China. This study investigates myocardial protection strategies in pediatric cardiopulmonary bypass (CPB) throughout China. Online questionnaires were delivered to 100 hospitals in 27 provinces. The number of yearly on-pump pediatric cardiovascular surgeries in these hospitals varied greatly. About 91.0% of respondents believe that each surgery should have at least two perfusionists, while only 64.0% of hospitals actually met this requirement. For pediatric patients, crystalloid cardioplegia was more prevalent than blood-based cardioplegia. Histidine-tryptophan-ketoglutarate solution and St. Thomas crystalloid solution were dominant among crystalloid cardioplegia. Del Nido cardioplegia and St. Thomas blood-based cardioplegia ranked the top two in the popularity of blood-based cardioplegia. Dosages varied among different kinds of cardioplegia. In the choice of different cardioplegia, perfusionists mainly focused on myocardial protective effect and cost. Hypothermia of cardioplegia solution was maintained by ice buckets in 3/4 of the hospitals in this survey. In conclusion, the essence of myocardial protection management during pediatric CPB was cardiac arrest induced by cardioplegia under systemic hypothermia. However, there is no uniform standard for the type of cardioplegia, or dosages. Therefore, well-designed multicenter randomized controlled trials are warranted to provide tangible evidence for myocardial protection of cardioplegia in pediatric CPB.

Effects of therapeutic hypothermia on cerebral tissue oxygen saturation in a swine model of post-cardiac arrest

Since the introduction of therapeutic hypothermia (TH), trends have changed in the monitoring indicators used during and after cardiac arrest. During hypothermia, the cerebral metabolic rate of oxygen is reduced, which leads to uncertainty in regional cerebral tissue oxygen saturation (S_ctO₂). The aim of the present study was to evaluate the effect of TH on changes in S_ctO₂ using near-infrared spectroscopy. A total of 23 male domestic pigs were randomized into three groups: TH (n=9), normothermia (NT; n=9) and control (n=5). Animals in the control group underwent surgical preparation only. The animal models were established using 8 min of ventricular fibrillation and 5 min of cardiopulmonary resuscitation. In the TH group, at 5 min after resuscitation, the animals were cooled with a cooling blanket and ice packs for 24 h. S_ctO₂ was recorded throughout the experiment. In all groups, The mean arterial pressure, arterial carbon dioxide partial pressure, arterial oxygen partial pressure, lactate, neuron-specific enolase (NSE) and S100B were measured at baseline and at 1, 3, 6, 12, 24 and 30 h after resuscitation. S_ctO₂ significantly decreased after ventricular fibrillation, compared with the baseline. Following resuscitation, the S_ctO₂ values gradually increased to 55.6±3.8% of baseline in the TH group and 51.2±3.5% in the NT group (P=0.039). Significant differences between the two groups were observed, starting at 6 h after cardiac arrest. Throughout the hypothermic period, NSE and S100B showed an increasing trend, then decreased during rewarming in the TH and NT groups. NSE and S100B showed greater improvement in the TH group compared with the NT group at 6 and 24 h after resuscitation. Following cardiac arrest, therapeutic hypothermia could increase S_ctO₂ after resuscitation and could improve neurological outcome. In conclusion, S_ctO₂ may be a feasible marker for use in the early assessment of brain damage during and after cardiac arrest.

Faster Hypothermia Induced by Esophageal Cooling Improves Early Markers of Cardiac and Neurological Injury After Cardiac Arrest in Swine

Background

After cardiopulmonary resuscitation, the protective effects of therapeutic hypothermia induced by conventional cooling are limited. Recently, esophageal cooling (EC) has been shown to be an effective, easily performed approach to induce therapeutic hypothermia. In this study we investigated the efficacy of EC and its effects on early markers of postresuscitation cardiac and neurological injury in a porcine model of cardiac arrest.

Methods and Results

Thirty‐two male domestic swine were randomized into 4 groups: sham control, normothermia, surface cooling, and EC. Sham animals underwent the surgical preparation only. Ventricular fibrillation was induced and untreated for 8 minutes while defibrillation was attempted after 5 minutes of cardiopulmonary resuscitation. At 5 minutes after resuscitation, therapeutic hypothermia was induced by either EC or surface cooling to reach a target temperature of 33°C until 24 hours postresuscitation, followed by a rewarming rate of 1°C/h for 5 hours. The temperature was normally maintained in the control and normothermia groups. After resuscitation, a significantly faster decrease in blood temperature was observed in the EC group than in the surface cooling group (2.8±0.7°C/h versus 1.5±0.4°C/h; P<0.05). During the maintenance and rewarming phases the temperature was maintained at an even level between the 2 groups. Postresuscitation cardiac and neurological damage was significantly improved in the 2 hypothermic groups compared with the normothermia group; however, the protective effects were significantly greater in the EC group.

Conclusions

In a porcine model of cardiac arrest, faster hypothermia successfully induced by EC was significantly better than conventional cooling in improving early markers of postresuscitation cardiac and neurological injury.

Effect of mild hypothermia on lung injury after cardiac arrest in swine based on lung ultrasound

BACKGROUND

Lung injury is common in post-cardiac arrest syndrome, and is associated with increased morbidity and mortality. The aim of this study was to evaluate the effect of mild hypothermia on lung injury after cardiac arrest in swine based on lung ultrasound.

METHODS

Twenty-three male domestic swine weighing 36 ± 2 kg were randomly assigned to three groups: therapeutic hypothermia (TH, n = 9), normothermia (NT, n = 9), and sham control (control, n = 5) groups. Sham animals only underwent surgical preparation. The animal model was established with 8 min of ventricular fibrillation followed by 5 min of cardiopulmonary resuscitation. Therapeutic hypothermia was induced and maintained until 24 h post-resuscitation in the TH group by surface blanket cooling, followed by rewarming at a rate of 1 °C/h for 5 h. The extravascular lung water index (ELWI), pulmonary vascular permeability index (PVPI), PO2/FiO2, and lung ultrasound score (LUS) were measured at baseline and at 1, 3, 6, 12, 24, and 30 h after resuscitation. After euthanizing the swine, their lung tissues were quickly obtained to evaluate inflammation.

RESULTS

After resuscitation, ELWI and PVPI in the NT group were higher, and PO2/FiO2 was lower, than in the sham group. However, those measures were significantly better in the TH group than the NT group. The LUS was higher in the NT group than in the sham group at 1, 3, 6, 12, 24, and 30 h after resuscitation. The LUS was significantly better in the TH group compared to the NT group. The lung tissue biopsy revealed that lung injury was more severe in the NT group than in the TH group. Increases in LUS were highly correlated with increases in ELWI (r = 0.613; p < 0.001) and PVPI (r = 0.683; p < 0.001), and decreases in PO2/FiO2 (r = - 0.468; p < 0.001).

CONCLUSIONS

Mild hypothermia protected against post-resuscitation lung injury in a swine model of cardiac arrest. Lung ultrasound was useful to dynamically evaluate the role of TH in lung protection.

Targeted temperature management for cardiac arrest

Therapeutic hypothermia, or targeted temperature management (TTM), is a strategy of reducing the core body temperature of survivors of sudden cardiac arrest (SCA) to minimize neurological damage caused by severe hypoxia. Initial clinical trials examining this technique demonstrated significant improvement in neurological function among survivors of out-of-hospital SCA with an initial shockable rhythm. Since then, TTM has become an integral part of the care provided to comatose survivors of SCA. However, multiple questions persist regarding the target cooling temperature, duration of cooling, and utility of TTM in patient populations such as survivors of out-of-hospital SCA with non-shockable rhythms or in-hospital SCA. This review article summarizes the current evidence regarding optimal application of TTM and compares the recommendations for TTM in current guidelines.