Propofol cardioplegia: A single-center, placebo-controlled, randomized controlled trial

Mitochondrial Dysfunction in Cardiac Surgery

Mitochondria are key to the cellular response to energetic demands, but are also vital to reactive oxygen species signaling, calcium hemostasis, and regulation of cell death. Cardiac surgical patients with diabetes, heart failure, advanced age, or cardiomyopathies may have underlying mitochondrial dysfunction or be more sensitive to perioperative mitochondrial injury. Mitochondrial dysfunction, due to ischemia/reperfusion injury and an increased systemic inflammatory response due to exposure to cardiopulmonary bypass and surgical tissue trauma, impacts myocardial contractility and predisposes to arrhythmias. Strategies for perioperative mitochondrial protection and recovery include both well-established cardio-protective protocols and targeted therapies that remain under investigation.

Efficacy of propofol-supplemented cardioplegia on biomarkers of organ injury in patients having cardiac surgery using cardiopulmonary bypass: A protocol for a randomised controlled study (ProMPT2)

INTRODUCTION

Cardiac surgery with cardiopulmonary bypass and cardioplegic arrest is known to be responsible for ischaemia and reperfusion organ injury. In a previous study, ProMPT, in patients undergoing coronary artery bypass or aortic valve surgery we demonstrated improved cardiac protection when supplementing the cardioplegia solution with propofol (6 mcg/ml). The aim of the ProMPT2 study is to determine whether higher levels of propofol added to the cardioplegia could result in increased cardiac protection.

METHODS AND ANALYSIS

The ProMPT2 study is a multi-centre, parallel, three-group, randomised controlled trial in adults undergoing non-emergency isolated coronary artery bypass graft surgery with cardiopulmonary bypass. A total of 240 patients will be randomised in a 1:1:1 ratio to receive either cardioplegia supplementation with high dose of propofol (12 mcg/ml), low dose of propofol (6 mcg/ml) or placebo (saline). The primary outcome is myocardial injury, assessed by serial measurements of myocardial troponin T up to 48 hours after surgery. Secondary outcomes include biomarkers of renal function (creatinine) and metabolism (lactate).

ETHICS AND DISSEMINATION

The trial received research ethics approval from South Central - Berkshire B Research Ethics Committee and Medicines and Healthcare products Regulatory Agency in September 2018. Any findings will be shared though peer-reviewed publications and presented at international and national meetings. Participants will be informed of results through patient organisations and newsletters.

TRIAL REGISTRATION

ISRCTN15255199. Registered in March 2019.

Efficacy of propofol-supplemented cardioplegia on biomarkers of organ injury in patients having cardiac surgery using cardiopulmonary bypass: a statistical analysis plan for the ProMPT-2 randomised controlled trial

BACKGROUND

The ProMPT-2 trial (Propofol for Myocardial Protection Trial #2) aims to compare the safety and efficacy of low- and high-dose propofol supplementation of the cardioplegia solution during adult cardiac surgery versus sham supplementation. This update presents the statistical analysis plan, detailing how the trial data will be analysed and presented. Outlined analyses are in line with the Consolidated Standards of Reporting Trials and the statistical analysis plan has been written prior to database lock and the final analysis of trial data to avoid reporting bias (following recommendations from the International Conference on Harmonisation of Good Clinical Practice).

METHODS/DESIGN

ProMPT-2 is a multi-centre, blinded, parallel three-group randomised controlled trial aiming to recruit 240 participants from UK cardiac surgery centres to either sham cardioplegia supplementation, low dose (6 µg/ml) or high dose (12 µg/ml) propofol cardioplegia supplementation. The primary outcome is cardiac-specific troponin T levels (a biomarker of cardiac injury) measured during the first 48 h following surgery. The statistical analysis plan describes the planned analyses of the trial primary and secondary outcomes in detail, including approaches to deal with missing data, multiple testing, violation of model assumptions, withdrawals from the trial, non-adherence with the treatment and other protocol deviations. It also outlines the planned sensitivity analyses and exploratory analyses to be performed.

DISCUSSION

This manuscript prospectively describes, prior to the completion of data collection and database lock, the analyses to be undertaken for the ProMPT-2 trial to reduce risk of reporting and data-driven analyses.

TRIAL REGISTRATION

ISRCTN ISRCTN15255199. Registered on 26 March 2019.

Cardioprotective effect of propofol in cardioplegia compared to systemic propofol in heart valves surgery; a randomized controlled trial

Background

Myocardial protection is still a focus of ongoing research. Propofol is used widely during the induction of anaesthesia in cardiac surgery. So, this triggers us to investigate the cardioprotective effect of the propofol when added to the cardioplegia compared to systemic propofol by measuring the troponin T level.

Methods

This clinical randomized controlled trial was carried out on 150 patients operated for elective valvular heart surgery. Patients were assigned into three equal groups: Group 1: received propofol in the cardioplegia, Group 2: received propofol injection in the aortic line before and after the aortic cross-clamp, and Group 3 (control group): patients without propofol in the cardioplegia or aortic line. All patients were subjected to full medical histories, physical examinations, routine tests, and echocardiography. Cardiac troponin T was measured before surgery and 4 times postoperatively.

Results

In group 1, there was a significant improvement in troponin T level at the last reading compared with the control group (mean ± SD. of group 1 was 246.4 ± 131.4, mean ± SD. of group 3 was 317.0 ± 117.9, p = 0.031), denoting propofol's cardioprotective effect when added as a cardioplegia additive. In group 2, there was a significant improvement of troponin T level at the last reading compared with the group 1 and control group (mean ± SD. of group 2 was 202.54 ± 156.03, mean ± SD. of group 3 was 317.0 ± 117.9, p < 0.001), denoting propofol's more cardioprotective effect when used systemically during cardiopulmonary bypass than when added as a cardioplegia additive.

Conclusions

In valvular cardiac surgery, propofol has an additional cardioprotective effect and a superior cardiac outcome when administered systematically during cardiopulmonary bypass rather than added to cardioplegia.

Trial registration

Pan African Clinical Trials Register PACTR201907764652028. Registered on 01 July 2019, retrospectively registered, https://pactr.samrc.ac.za/ TrialDisplay.aspx?TrialID = 5726.

Propofol protects cardiomyocytes from doxorubicin-induced toxic injury by activating the nuclear factor erythroid 2-related factor 2/glutathione peroxidase 4 signaling pathways

Propofol offers important protective effects in ischemia/reperfusion-induced cardiomyocyte injury, but its specific mechanisms in doxorubicin (DOX)-induced cardiotoxicity have not been investigated. In this paper, we attempted to explore the effects of propofol on DOX-induced human cardiomyocyte injury and its related mechanisms. H9c2 cell viability was assessed by cell counting kit-8 and lactate dehydrogenase assay kit. Nuclear factor erythroid 2-related factor 2 (NRF2)/glutathione peroxidase 4 (GPx4) signaling pathway-related protein levels were measured by Western blot. Ferroptosis was evaluated by corresponding kits and Western blot and apoptosis was detected by CCK-8, terminal deoxynucleotidyl transferase dUTP nick-end labeling and Western blot. Oxidative stress was assessed by reactive oxygen species kit and the commercial kits, and inflammation response was analyzed by enzyme-linked immunosorbent assay and Western blot. The results showed that propofol attenuated DOX-induced cytotoxicity and activated Nrf2/GPx4 signaling pathways in H9c2 cells. In addition, propofol also alleviated DOX-induced ferroptosis, increased cell viability and inhibited apoptosis, oxidative stress and inflammatory responses in H9c2 cells through activation of Nrf2/GPx4 signaling pathways. In summary, propofol provides the protection against DOX-induced cardiomyocyte injury by activating Nrf2/GPx4 signaling, providing a new approach and theoretical basis for the repair of cardiomyocytes.

Remote ischaemic preconditioning in isolated aortic valve and coronary artery bypass surgery: a randomized trial†

OBJECTIVES

This trial was designed and patients were recruited at a time when the benefits of remote ischaemic preconditioning during open-heart surgery were still controversial. We focused on a homogeneous patient population undergoing either isolated aortic valve replacement or coronary artery bypass grafting (CABG) surgery by investigating cardiac injury, metabolic stress and inflammatory response.

METHODS

A 2-centre randomized controlled trial recruited a total of 124 patients between February 2013 and April 2015. Of them, 64 patients underwent CABG and 60 patients underwent aortic valve replacement. Patients were randomized to either sham or preconditioning. Remote ischaemic preconditioning was applied following anaesthesia and before sternotomy. Myocardial injury and inflammatory response were assessed by serially measuring cardiac troponin I, and interleukin-6, 8, 10 and the tumour necrosis factor (TNF-α). Biopsies from the left and the right ventricles were harvested after ischaemic reperfusion injury for nucleotides analysis.

RESULTS

Application of remote ischaemic preconditioning did not alter the degree of troponin I release, levels of inflammatory markers and cardiac energetics in both the CABG and the aortic valve replacement groups.

CONCLUSIONS

Preconditioning did not confer any additional cardioprotection in terms of reducing the levels of troponin I and inflammatory markers and preserving left and right ventricle energy metabolites in patients undergoing isolated CABG or aortic valve surgery.

CLINICAL TRIAL REGISTRATION NUMBER

International Standard Randomized Controlled Trial Number (ISRCTN) registry ID 33084113 (doi: 10.1186/ISRCTN33084113) and UK controlled randomized trial number (UKCRN) registry ID 13672.

Mitochondrial Dysfunction in Cardiac Surgery

Mitochondria are key to the cellular response to energetic demand, but are also vital to reactive oxygen species signaling, calcium hemostasis, and regulation of cell death. Cardiac surgical patients with diabetes, heart failure, advanced age, or cardiomyopathies may have underlying mitochondrial dysfunction or be more sensitive to perioperative mitochondrial injury. Mitochondrial dysfunction, due to ischemia/reperfusion injury and an increased systemic inflammatory response due to exposure to cardiopulmonary bypass and surgical tissue trauma, impacts myocardial contractility and predisposes to arrhythmias. Strategies for perioperative mitochondrial protection and recovery include both well-established cardioprotective protocols and targeted therapies that remain under investigation.

A Trial of Two Anesthetic Regimes for Minimally Invasive Mitral Valve Repair

OBJECTIVE

Minimally invasive mitral valve repair may be associated with prolonged cardioplegic arrest times and ischemic reperfusion injury. Intravenous (propofol) and volatile (sevoflurane) anesthesia are used routinely during cardiac surgery and are thought to provide cardioprotection; however, the individual contribution of each regimen to cardioprotection is unknown. Therefore, the authors sought to compare the cardioprotective effects of propofol and sevoflurane anesthesia in patients undergoing minimally invasive mitral valve repair.

DESIGN

A single-center single-blind randomized controlled trial.

SETTING

A specialized regional cardiac surgery center in Italy.

PARTICIPANTS

The study enrolled 62 adults undergoing elective isolated minimally invasive mitral valve repair for degenerative disease. Exclusion criteria included secondary mitral regurgitation, previously treated coronary artery disease, diabetes mellitus, chronic renal failure requiring dialysis, atrial fibrillation, and documented allergy to either propofol or sevoflurane.

INTERVENTIONS

All patients received video-assisted minimally invasive right minithoracotomy. Patients were randomized to receive propofol or sevoflurane anesthesia in a 1:1 ratio.

MEASUREMENTS AND MAIN RESULTS

Cardiac troponin I release was measured over the first 72 hours postoperatively. Operative, cross-clamp, and total bypass times were similar between groups. Cardiac troponin I release was reduced nonsignificantly in the propofol group (p = 0.62), and peak troponin I release was correlated with cross-clamp time in both groups. There were no differences in terms of intraoperative lactate release and blood pH between groups.

CONCLUSION

Propofol and sevoflurane anesthesia were associated with similar degrees of myocardial injury, indicating comparable cardioprotection. Myocardial injury was related directly to the duration of cardioplegic arrest.

Myocardial ischaemia reperfusion injury: the challenge of translating ischaemic and anaesthetic protection from animal models to humans

Myocardial ischaemia reperfusion injury is the leading cause of death in patients with cardiovascular disease. Interventions such as ischaemic pre and postconditioning protect against myocardial ischaemia reperfusion injury. Certain anaesthesia drugs and opioids can produce the same effects, which led to an initial flurry of excitement given the extensive use of these drugs in surgery. The underlying mechanisms have since been extensively studied in experimental animal models but attempts to translate these findings to clinical settings have resulted in contradictory results. There are a number of reasons for this such as dose response, the intensity of the ischaemic stimulus applied, the duration of ischaemia and lost or diminished cardioprotection in common co-morbidities such as diabetes and senescence. This review focuses on current knowledge regarding myocardial ischaemia reperfusion injury and cardioprotective interventions both in experimental animal studies and in clinical trials.

Propofol Protects Rat Cardiomyocytes from Anthracycline-Induced Apoptosis by Regulating MicroRNA-181a In Vitro and In Vivo

We aimed to evaluate the cardioprotective effect and mechanism of propofol in anthracycline-induced cardiomyocyte apoptosis. We selected the rat myocardial cell line, H9c2, and primary cardiomyocytes for in vitro study. The cardiomyocytes were treated with vehicle, Adriamycin® (ADM), propofol, or a combination of ADM and propofol. The proportion of apoptotic cells and the expression of miR-181a were detected by flow cytometry and real-time PCR, respectively. Luciferase assays were performed to explore the direct target gene of miR-181a. In vivo assay, rats were randomly divided into different treatment groups. The apoptosis index was determined by TUNEL staining, and the expression of miR-181a and STAT3 in heart tissue was detected. The antiproliferative effect of ADM alone was significantly greater than that of ADM plus propofol. A significantly greater decrease in the proportion of apoptotic cells and in miR-181a expression was observed in the combination treatment group compared with that in the ADM groups in vitro and in vivo. The loss-of-function of miR-181a in H9c2 of ADM treatment resulted in increased Bcl-2 and decreased Bax. MiR-181a suppressed Bcl-2 expression through direct targeting of the Bcl-2 transcript. Propofol reduced anthracycline-induced apoptosis in cardiomyocytes via targeting miR-181a/Bcl-2, and a negative correlation between miR-181a and Bcl-2 was observed.

Sedation After Cardiac Surgery: Is One Drug Better Than Another?

The classic high-dose narcotic-based cardiac anesthetic has been modified to facilitate a fast-track, rapid recovery in the intensive care unit (ICU). Postoperative sedation is consequently now an essential component in recovery of the patient undergoing cardiac surgery. It must facilitate the patient's unawareness of the environment as well as reduce the discomfort and anxiety caused by surgery, intubation, mechanical ventilation, suction, and physiotherapy. Benzodiazepines seem well suited for this role, but propofol, opioids, and dexmedetomidine are among other agents commonly used for sedation in the ICU. However, what is an ideal sedative for this application? When compared with benzodiazepine-based sedation regimens, nonbenzodiazepines have been associated with shorter duration of mechanical ventilation and ICU length of stay. Current sedation guidelines recommend avoiding benzodiazepine use in the ICU. However, there are no recommendations on which alternatives should be used. In postcardiac surgery patients, inotropes and vasoactive medications are often required because of the poor cardiac function. This makes sedation after cardiac surgery unique in comparison with the requirements for most other ICU patient populations. We reviewed the current literature to try to determine if 1 sedative regimen might be better than others; in particular, we compare outcomes of propofol and dexmedetomidine in postoperative sedation in the cardiac surgical ICU.

9th Hatter Biannual Meeting: position document on ischaemia/reperfusion injury, conditioning and the ten commandments of cardioprotection

In the 30 years since the original description of ischaemic preconditioning, understanding of the pathophysiology of ischaemia/reperfusion injury and concepts of cardioprotection have been revolutionised. In the same period of time, management of patients with coronary artery disease has also been transformed: coronary artery and valve surgery are now deemed routine with generally excellent outcomes, and the management of acute coronary syndromes has seen decade on decade reductions in cardiovascular mortality. Nonetheless, despite these improvements, cardiovascular disease and ischaemic heart disease in particular, remain the leading cause of death and a significant cause of long-term morbidity (with a concomitant increase in the incidence of heart failure) worldwide. The need for effective cardioprotective strategies has never been so pressing. However, despite unequivocal evidence of the existence of ischaemia/reperfusion in animal models providing a robust rationale for study in man, recent phase 3 clinical trials studying a variety of cardioprotective strategies in cardiac surgery and acute ST-elevation myocardial infarction have provided mixed results. The investigators meeting at the Hatter Cardiovascular Institute workshop describe the challenge of translating strong pre-clinical data into effective clinical intervention strategies in patients in whom effective medical therapy is already altering the pathophysiology of ischaemia/reperfusion injury-and lay out a clearly defined framework for future basic and clinical research to improve the chances of successful translation of strong pre-clinical interventions in man.