Myocardial oxidative stress, and cell injury comparing three different techniques for coronary artery bypass grafting

Management of Severe Mitral Regurgitation in Patients With Acute Myocardial Infarction: JACC Focus Seminar 2/5

Severe acute mitral regurgitation after myocardial infarction includes partial and complete papillary muscle rupture or functional mitral regurgitation. Although its incidence is <1%, mitral regurgitation after acute myocardial infarction frequently causes hemodynamic instability, pulmonary edema, and cardiogenic shock. Medical management has the worst prognosis, and mortality has not changed in decades. Surgery represents the gold standard, but it is associated with high rates of morbidity and mortality. Recently, transcatheter interventions have opened a new door for management that may improve survival. Mechanical circulatory support restores vital organ perfusion and offers the opportunity for a steadier surgical repair. This review focuses on the diagnosis and the interventional management, both surgical and transcatheter, with a glance on future perspectives to enhance patient management and eventually decrease mortality.

Percutaneous mitral valve repair in patients developing severe mitral regurgitation early after an acute myocardial infarction: A review

Acute mitral regurgitation (MR) may develop in the setting of an acute myocardial infarction (AMI) because of papillary muscle dysfunction or rupture. Severe acute MR in this scenario is a life-threatening complication associated with hemodynamic instability and pulmonary edema, and has been linked to a worse prognosis even after reperfusion. Patients treated solely with medical therapy have the highest mortality rates. Surgery has been the only treatment strategy until recently, but the results of the technique are hindered by high rates of morbidity and mortality. Therefore, the development of less invasive interventions for correcting MR would be ideal. We aimed to review the current role of transcatheter interventions in this clinical setting.

Rescue transventricular off-pump mitral valve repair with artificial neochords for acute mitral regurgitation due to postinfarction papillary muscle rupture

BACKGROUND

We report 3 cases of rescue transventricular off-pump mitral valve (MV) repair in high-risk patients with acute mitral regurgitation (MR) due to post-myocardial infarction (MI) papillary muscle rupture (PMR).

METHODS

The 3 patients presented with acute inferior ST elevation myocardial infarction, cardiogenic shock, and pulmonary edema. Their preoperative peak troponin I levels were 1909 ng/L, 16,963 ng/L, and 8299 ng/L. All 3 patients underwent successful percutaneous intervention to the culprit coronary artery, and antiplatelet therapy was initiated. All patients required inotropic support and had an intra-aortic balloon pump inserted preoperatively. Transesophageal echocardiography (TEE) demonstrated severe eccentric MR due to the leaflet prolapse secondary to PMR. The patients' estimated EuroSCORE II scores were 16.03%, 16.68%, and 7.81%, and their Society of Thoracic Surgeons scores were 14.77%, 18.24%, and 9.8%, respectively. All 3 patients underwent urgent transventricular off-pump MV repair using artificial chords, with 2 or 3 three neochords implanted. The duration of operation was <2 hours, and intraoperative and postoperative drainage was minimal in all cases. MV function was assessed by qualitative and semiquantitative TEE.

RESULTS

Intraoperative MR reduction to a mild level was achieved in all 3 patients. All patients had moderate MR at discharge, likely due to left ventricular remodeling. Severe MR recurred in all patients, at 5, 4, and 2 months of follow-up, respectively. All 3 patients underwent an elective MV reoperation via conventional approach.

CONCLUSIONS

Off-pump transventricular MV repair may offer a safe and feasible alternative to stabilize high-risk patients with acute MR due to post-MI PMR. Although early MR recurrence is concerning, urgent transventricular MV repair may serve as a bridge to conventional surgery in such unstable patients.

Use of MitraClip for mitral valve repair in patients with acute mitral regurgitation following acute myocardial infarction: Effect of cardiogenic shock on outcomes (IREMMI Registry)

OBJECTIVES

To assess outcomes in patients with acute mitral regurgitation (MR) following acute myocardial infarction (AMI) who received percutaneous mitral valve repair (PMVR) with the MitraClip device and to compare outcomes of patients who developed cardiogenic shock (CS) to those who did not (non-CS).

BACKGROUND

Acute MR after AMI may lead to CS and is associated with high mortality.

METHODS

This registry analyzed patients with MR after AMI who were treated with MitraClip at 18 centers within eight countries between January 2016 and February 2020. Patients were stratified into CS and non-CS groups. Primary outcomes were mortality and rehospitalization due to heart failure. Secondary outcomes were acute procedural success, functional improvement, and MR reduction. Multivariable Cox regression analysis evaluated association of CS with clinical outcomes.

RESULTS

Among 93 patients analyzed (age 70.3 ± 10.2 years), 50 patients (53.8%) experienced CS before PMVR. Mortality at 30 days (10% CS vs. 2.3% non-CS; p = .212) did not differ between groups. After median follow-up of 7 months (IQR 2.5-17 months), the combined event mortality/re-hospitalization was similar (28% CS vs. 25.6% non-CS; p = .793). Likewise, immediate procedural success (90% CS vs. 93% non-CS; p = .793) and need for reintervention (CS 6% vs. non-CS 2.3%, p = .621) or re-admission due to HF (CS 13% vs. NCS 23%, p = .253) at 3 months did not differ. CS was not independently associated with the combined end-point (hazard ratio 1.1; 95% CI, 0.3-4.6; p = .889).

CONCLUSIONS

Patients found to have significant MR during their index hospitalization for AMI had similar clinical outcomes with PMVR whether they presented in or out of cardiogenic shock, provided initial hemodynamic stabilization was first achieved before PMVR.

Is there really a benefit of using minimized cardiopulmonary bypass in CABG? A retrospective propensity score-matched study with 5000 cases

The concept of minimized cardiopulmonary bypass targets at reduction of adverse effects triggered by extracorporeal circulation. In this study, benefits of minimized bypass in CABG were evaluated under particular consideration of patient body mass index and surgeon impact. From 2004 to 2014, 5164 patients underwent coronary bypass surgery (CABG). Conventional cardiopulmonary bypass (CCPB) was used in 2376 patients, minimized cardiopulmonary bypass (MCPB) in 2788 cases. Multivariate regression models were used in the entire cohort and in a propensity score-matched subgroup after expert CABG to figure out clinical differences such as mortality, postoperative renal function, and thromboembolic events. Overall mortality was 1.5% (n = 41) in the MCPB group and 3.5% (n = 82) in CCPB patients (p < 0.001). Postoperative renal failure and hemodialysis occurred in 2.6% (n = 72/MCPB) vs. 5.3% (n = 122/CCPB (p < 0.001). Multivariable regression revealed use of CCPB as risk factor for increased mortality (OR 2.01, p = 0.001), renal failure (OR 1.79, p < 0.001), and myocardial infarction (OR 1.98, p < 0.001) comparable to risk factors such as preoperative ventilation (OR 2.26, p = 0.048), diabetes mellitus (OR 1.68, p = 0.001), and cardiogenic shock (OR 3.81, p = 0.002). Body mass index had no effect on the analyzed outcome parameters (OR 0.92, p = 0.002). Propensity score-matching analysis of an expert CABG subgroup revealed CCPB as risk factor for mortality (OR 2.26, p = 0.004) and postoperative hemodialysis (OR 1.74, p = 0.017). Compared to conventional circuits, minimized bypass use in CABG is associated with lower mortality and less postoperative renal failure. A high body mass index is feasible and not a risk factor for MCPB surgery.

Effects of N-acetyl cysteine and melatonin on early reperfusion injury in patients undergoing coronary artery bypass grafting: A randomized, open-labeled, placebo-controlled trial

OBJECTIVES

This study assessed the efficacy of oral consumption of N-acetyl cysteine (NAC) and melatonin (ML) in reducing early reperfusion injury and acute oxidative stress in patients undergoing coronary artery bypass grafting (CABG) with respect to the measurements of cardiac troponin I, lactate, malondealdehyde (MDA), and tumor necrosis factor-α (TNF-α) levels in the blood.

METHODS

This study was a randomized, open-label, placebo-controlled trial. Eighty eight patients, aged between 39 to 76 years and eligible for CABG, were recruited and randomly assigned into 3 intervention groups through a simple randomization method and underwent CABG surgery. Blood samples were withdrawn from arterial line, before the induction of anesthesia (before the start of surgery), after incision (before aortic cross-clamping), during global ischemia (during aortic cross-clamping), after aortic cross-clamping (on set of reperfusion), 15 minutes after reperfusion, and after recovery at the intense care unit. The blood samples were analyzed for troponin I, lactate, MDA and TNF-α levels.

RESULTS

There was no significant difference in influencing variables among the groups at the baseline. Overall mean troponin I, lactate, and TNF- α levels were significantly different between the intervention groups (all P < .001) at the recovery phase. Post-hoc pairwise comparisons showed that the differences of mean serum levels between ML and control groups were statistically significant for MDA, TNF- α, lactate, and troponin I (P < .001, P = .001, and P = .001, respectively). The differences between NAC and control groups and between ML and NAC groups were only significant for mean lactate level (P < .001).

CONCLUSION

The current study revealed that ML and NAC are potent antioxidants with similar efficacy in terms of reducing CABG related cardiac injury and oxidative stress with the dosage employed for the intervention.

Acute-phase proteins and oxidative stress in patients undergoing coronary artery bypass graft: comparison of cardioplegia strategy

Introduction

Several strategies are still being introduced to cardiac surgery techniques to reduce the signs of the inflammatory response and oxidative stress. Many efforts have been made to develop the best possible method for myocardial protection.

Aim

To assess the effect of the cardioplegia strategy on the systemic inflammatory response and oxidative stress.

Material and methods

A group of 238 consecutive, elective on-pump coronary artery bypass graft patients (CABG; 183 men, aged 64.6 ±8.1 years) were prospectively studied. Patients were enrolled in two groups: with warm blood cardioplegia (n = 124) and with cold crystalloid cardioplegia (n = 114). In each group, pre- and postoperative levels of plasma C-reactive protein, fibrinogen, interleukin 6 and 8-iso-prostaglandin F_2α (8-iso-PGF_2α) were measured.

Results

All studied markers significantly increased 18–36 h following CABG and then decreased in 5–7 postoperative days but remained above baseline levels. No differences in terms of studied markers and clinical outcomes were noted for the different types of cardioplegia. Regression analysis showed a significant correlation between preoperative level of oxidative stress measured by 8-iso-PGF_2α and postoperative myocardial infarction as well as in-hospital cardiovascular death (p = 0.047 and p = 0.041 respectively).

Conclusions

This study extends previous reports by showing that the type of cardioplegia does not affect the systemic inflammatory response or oxidative stress, which are associated with the CABG procedure. It might be speculated that preoperative screening of oxidative stress could be helpful in identifying patients at increased risk of an unfavorable course after CABG.

Minimally Invasive Extracorporeal Circulation Circuit Is Not Inferior to Off-Pump Coronary Artery Bypass Grafting: Meta-Analysis Using the Bayesian Method

The pathophysiologic side effects of cardiopulmonary bypass have already been identified. Minimally invasive extracorporeal circulation technologies (MiECT) and off-pump coronary artery bypass graft surgery (OPCABG) aim to reduce these problems. This meta-analysis provides a comparison of MiECT and OPCABG in randomized and observational studies. A fully probabilistic, Bayesian approach of primary and secondary endpoints was conducted. MiECT does not give inferior results when compared with OPCABG. However, there is a trend to borderline significantly higher blood loss in this group in randomized controlled trials. The question whether MiECT is equivalent to OPCABG can be answered with the affirmative, but long-term follow-up data are needed to detect any advantage over time.

Relationship between high on aspirin platelet reactivity and oxidative stress in coronary artery by-pass grafted patients

The aim of the study was to assess the responsiveness of blood platelets to acetylsalicylic acid (ASA) in patients following coronary artery bypass grafting (CABG) surgery with relation to oxidative and antioxidative plasma status. The study included 37 patients treated with the CABG procedure. During the first 24 h after CABG patients were given 300 mg of ASA with the following dose of 150 mg daily. The blood was collected before the procedure and 10 days after. Whole blood platelet aggregation induced with arachidonic acid, collagen and adenosine diphosphate (ADP) was performed together with whole blood generation of thromboxane B2 (TxB2). Oxidative stress was measured before and 10 days after CABG with total oxidative plasma status (TOS) and total antioxidative status of the plasma (TAS). TOS/TAS index was calculated. We observed a significant increase in the TOS and TOS/TAS index and ADP-induced aggregation 10 days after CABG in comparison with its level before operation. There was a significant decrease in the arachidonic acid-induced aggregation and serum TxB2 level. Patients with ADP-induced and collagen-induced aggregation in the upper quartile had significantly higher TOS and TOS/TAS index before (ADP) and after the operation (ADP and collagen). There were 19 patients (51%) with high on aspirin platelet reactivity after CABG who had also higher TOS and TOS/TAS index and lower TAS value in comparison with aspirin responders. Despite ASA use, increased oxidative stress after CABG can overcome its antiplatelet effect and increase platelet activation through other pathways.

Minimally invasive extracorporeal circulation improves quality of life after coronary artery bypass grafting

OBJECTIVES

The effect on postoperative health-related quality of life (HRQoL) after coronary artery bypass grafting (CABG) surgery with conventional cardiopulmonary bypass (cCPB) and off-pump surgery has been investigated extensively; however, there are no studies focusing on HRQoL after surgery with minimally invasive extracorporeal circulation (MiECC). Therefore, we sought to prospectively investigate the effect of MiECC on postoperative HRQoL when compared with cCPB in patients undergoing CABG over a short-term (3-month) follow-up period.

METHODS

Sixty patients scheduled for elective CABG surgery were randomly assigned into two groups: those who had surgery on MiECC system (n = 30) and those who underwent CABG using cCPB (n = 30). Quality-of-life assessment was performed preoperatively (baseline-T0), at first postoperative month (T1) and at 3-month follow-up (T3). The RAND SF-36 scale was used for data collection, which included both sociodemographic and clinical characteristics of patients. The primary outcome of the study was quantitative measurement of postoperative HRQoL at 3-month follow-up.

RESULTS

Both groups were balanced in terms of demographic, socio-economic and operative characteristics. At 3-month follow-up, mean SF-36 component and summary scores in each group were higher in absolute values than the respective mean baseline scores, apart from role-physical score in patients operated with cCPB. Patients operated on MiECC showed uniformly significantly higher values in all individual and summary domains, whereas patients operated on cCPB showed significant improvement in 6/8 individual domains. Patients operated on MiECC showed a more pronounced increase in SF-36 individual domain scores from the first to the third postoperative month when compared with cCPB, which was statistically significant regarding physical functioning (P = 0.001), role-physical (P < 0.001), vitality (P = 0.01) and role-emotional (P = 0.004). This resulted in a significant improvement in physical (P = 0.002) and mental (P = 0.01) summary scores.

CONCLUSIONS

The current study proves that MiECC significantly improves HRQoL after coronary surgery compared with cCPB. This finding, combined with results from large-scale studies showing superior clinical outcomes from its use, enhances the role of MiECC as a dominant technique in coronary revascularization surgery.

Myocardial Oxidative Stress in Infants Undergoing Cardiac Surgery

Cardiac surgery for congenital heart disease often necessitates a period of myocardial ischemia during cardiopulmonary bypass and cardioplegic arrest, followed by reperfusion after aortic cross-clamp removal. In experimental models, myocardial ischemia-reperfusion is associated with significant oxidative stress and ventricular dysfunction. A prospective observational study was conducted in infants (<1 year) who underwent elective surgical repair of a ventricular septal defect (VSD) or tetralogy of Fallot (TOF). Blood samples were drawn following anesthetic induction (baseline) and directly from the coronary sinus at 1, 3, 5, and 10 min following aortic cross-clamp removal. Samples were analyzed for oxidant stress using assays for thiobarbituric acid-reactive substances, protein carbonyl, 8-isoprostane, and total antioxidant capacity. For each subject, raw assay data were normalized to individual baseline samples and expressed as fold-change from baseline. Results were compared using a one-sample t test with Bonferroni correction for multiple comparisons. Sixteen patients (ten with TOF and six with VSD) were enrolled in the study, and there were no major postoperative complications observed. For the entire cohort, there was an immediate, rapid increase in myocardial oxidative stress that was sustained for 10 min following aortic cross-clamp removal in all biomarker assays (all P < 0.01), except total antioxidant capacity. Infant cardiac surgery is associated with a rapid, robust, and time-dependent increase in myocardial oxidant stress as measured from the coronary sinus in vivo. Future studies with larger enrollment are necessary to assess any association between myocardial oxidative stress and early postoperative outcomes.

Use of minimal invasive extracorporeal circulation in cardiac surgery: principles, definitions and potential benefits. A position paper from the Minimal invasive Extra-Corporeal Technologies international Society (MiECTiS)

Minimal invasive extracorporeal circulation (MiECC) systems have initiated important efforts within science and technology to further improve the biocompatibility of cardiopulmonary bypass components to minimize the adverse effects and improve end-organ protection. The Minimal invasive Extra-Corporeal Technologies international Society was founded to create an international forum for the exchange of ideas on clinical application and research of minimal invasive extracorporeal circulation technology. The present work is a consensus document developed to standardize the terminology and the definition of minimal invasive extracorporeal circulation technology as well as to provide recommendations for the clinical practice. The goal of this manuscript is to promote the use of MiECC systems into clinical practice as a multidisciplinary strategy involving cardiac surgeons, anaesthesiologists and perfusionists.

Prognostic indicators after cardiac surgery in children and their relationship with the oxidative stress response

OBJECTIVES

To analyse the trend in lipid peroxidation and antioxidant response as key markers of oxidative stress after paediatric cardiovascular surgery, and compare them with other internationally accepted clinical prognostic indicators.

PATIENTS AND METHODS

A prospective study was conducted on 30 children aged one month to 14 years, weight>5 kg, undergoing cardiopulmonary bypass surgery. Blood samples were taken just before the intervention, immediately after surgery, and after 18-20 h. Cell membrane lipid peroxidation was analysed by quantifying malondialdehyde, as well as measuring total glutathione (oxidized and reduced), as representatives of antioxidant response. An analysis was also performed on clinical variables for establishing a score for the systemic inflammatory response syndrome associated with cardiopulmonary bypass.

RESULTS

The study included 30 children with a mean age of 4.1 years old (interquartile range [IQR]: 2.7; 8.0). Of these, 62.1% were girls. The standard deviation of the median weight was -0.39 (IQR: -0.76; 0.24), the median height was -0.22 (IQR: -0.74; 0.27), and the median BMI was -0.43 (IQR: -1; 0.45). The final surgery times were divided into 2 parts: total time of extracorporeal circulation, with a mean of 79 min (IQR: 52.5; 125.5), and the clamping time, a measurement included in the previous figure with a mean value of 38.5 min (IQR: 22; 59). Malondialdehyde increased and glutathione decreased in postoperative time, with clear, statistically significant direct correlation between time of extracorporeal circulation and percentage decrease in total glutathione between preoperative and immediate postoperative time, and a decline between the preoperative and late postoperative. There was a statistical correlation between total glutathione levels at 18-20 h postoperatively and the duration of mechanical ventilation and inflammatory systemic response syndrome.

CONCLUSIONS

Surgery with extracorporeal circulation performed in children activates inflammatory mediators, being maximum after aortic clamping, and improving after the first 24h. The level of oxidative stress activation depends on surgical times. The development of systemic inflammatory response syndrome is associated with longer duration of mechanical ventilation, longer stay in intensive care, higher scores in the Aristotle model and longer surgical times. Those who do not meet criteria for inflammatory response have higher levels of glutathione in first 24h.

Is there any difference between blood and crystalloid cardioplegia for myocardial protection during cardiac surgery? A meta-analysis of 5576 patients from 36 randomized trials

Objective:

To compare the efficacy of blood versus crystalloid cardioplegia for myocardial protection in patients undergoing cardiac surgery.

Methods:

MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar and reference lists of relevant articles were searched for clinical studies that reported in-hospital outcomes after blood or crystalloid cardioplegia for myocardial protection during cardiac surgery procedures from 1966 to 2011. The principal summary measures were risk ratio (RR) for blood compared to crystalloid cardioplegia with 95% Confidence Interval (CI) and P values (considered statistically significant when <0.05). The RRs were combined across studies using the DerSimonian-Laird random effects model and fixed effects model using the Mantel-Haenszel model - both models were weighted. The meta-analysis was completed using the software Comprehensive Meta-Analysis version 2 (Biostat Inc., Englewood, New Jersey).

Results:

Thirty-six studies (randomized trials) were identified and included a total of 5576 patients (2834 for blood and 2742 for crystalloid). There was no significant difference between the blood and crystalloid groups in the risk for death (risk ratio [RR] 0.951, 95% CI 0.598 to 1.514, P=0.828, for both effect models) or myocardial infarction (RR 0.795, 95% CI 0.547 to 1.118, P=0.164, for both effect models) or low cardiac output syndrome (RR 0.765, 95% CI 0.580 to 1.142, P=0.094, for the fixed effect model; RR 0.690, 95% CI 0.480 to 1.042, P=0.072, for the random effect model). It was observed that there was no publication bias or heterogeneity of effects about any outcome.

Conclusion:

We found evidence that argues against any superiority in terms of hard outcomes between blood or crystalloid cardioplegia for myocardial protection during cardiac surgery.

Does on-pump normothermic beating-heart valve surgery with low tidal volume ventilation protect the lungs?

BACKGROUND

Postoperative pulmonary dysfunction following cardiopulmonary bypass (CPB) usually develops secondary to the inflammatory process with contact activation, hypothermia, operative trauma, general anesthesia, atelectasis, pain, and pulmonary ischemia/reperfusion due to cross-clamping. The aim of the present study was to evaluate the effects of an on-pump, normothermic, and beating-heart technique and of low-volume ventilation on lung injury.

METHODS

We compared the results for 20 patients who underwent operations with an on-pump, normothermic, and beating-heart technique of mitral valve surgery with low-volume ventilation (group 1) with the results for 23 patients who underwent their operations with an on-pump, hypothermic cardiac-arrest technique (group 2). In both groups, blood samples were collected from the right superior pulmonary vein, and inflammation and oxidative stress markers (malondialdehyde, lactic acid, platelet-activating factor, and myeloperoxidase) were studied.

RESULTS

Malondialdehyde, myeloperoxidase, and lactate values were significantly lower in group 1 than in group 2 just before the termination of CPB (P < .05). We observed no differences between the 2 groups with regard to values for platelet-activating factor.

CONCLUSIONS

Inflammation and oxidative stress markers were lower in the group of patients who underwent beating-heart valve surgery with low-volume ventilation. These results reflect less of an ischemic insult and lower inflammation compared with the results for the patients who underwent conventional operations.

The effect of remote ischaemic preconditioning on myocardial injury in patients undergoing off-pump coronary artery bypass graft surgery

In several recent clinical trials on cardiac surgery patients, remote ischaemic preconditioning (RIPC) showed a powerful myocardial protective effect. However the effect of RIPC has not been studied in patients undergoing off-pump coronary artery bypass graft surgery. We evaluated whether RIPC could induce myocardial protection in off-pump coronary artery bypass graft surgery patients. Patients undergoing elective off-pump coronary artery bypass graft surgery were randomly allocated to the RIPC (n = 65) or control group (n = 65). After induction of anaesthesia, RIPC was induced by four cycles of five-minute ischaemia and reperfusion on the upper limb using a pneumatic cuff. Anaesthesia was maintained with sevoflurane, remifentanil and vecuronium. Myocardial injury was assessed by troponin I before surgery and 1, 6, 12, 24, 48 and 72 hours after surgery. There were no statistical differences in troponin I levels between RIPC and control groups (P = 0.172). Although RIPC reduced the total amount of troponin I (area under the curve of troponin increase) by 26%, it did not reach statistical significance (RIPC group 53.2 +/- 72.9 hours x ng/ml vs control group 67.4 +/- 97.7 hours x ng/ml, P = 0.281). In this study, RIPC by upper limb ischaemia reduced the postoperative myocardial enzyme elevation in off-pump coronary artery bypass graft surgery patients, but this did not reach statistical significance. Further study with a larger number of patients may be needed to fully evaluate the clinical effect of RIPC in off-pump coronary artery bypass graft surgery patients.