2021: The American Association for Thoracic Surgery Expert Consensus Document: Coronary artery bypass grafting in patients with ischemic cardiomyopathy and heart failure

Mechanical Circulatory Support During Surgical Revascularization for Ischemic Cardiomyopathy

BACKGROUND

This study aimed to describe the use of perioperative mechanical circulatory support (MCS) and its impact on outcomes in patients with ischemic cardiomyopathy who were undergoing surgical revascularization.

METHODS

Patients with an ejection fraction <35% who underwent isolated coronary artery bypass grafting (CABG) from 2015 to 2021 were identified (N = 378). Patients were divided into no MCS, preoperative MCS, and postoperative MCS groups on the basis of timing of MCS initiation, which included intraaortic balloon pump, extracorporeal membrane oxygenation, or Impella device (Abiomed) use. The primary outcome of interest was operative mortality.

RESULTS

The median Society of Thoracic Surgeons Predicted Risk of Mortality was 2.4%. Sixty-six percent (n = 246) of patients had a previous myocardial infarction, and 61.8% of these patients were within 21 days of CABG. Twenty-one patients (5.6%) presented in cardiogenic shock. The preoperative MCS cohort consisted of 31 patients (8.2%) who underwent CABG a median of 2 days after MCS initiation. Thirty (7.9%) patients required postoperative MCS. Independent risk factors for requiring postoperative MCS included the preoperative ejection fraction (odds ratio, 0.93; P = .01 and the presence of preoperative MCS (odds ratio, 3.06; P = .02). Overall, operative mortality was 3.4%, and 3-year survival was 87.0%. Operative mortality in patients who did and did not receive preoperative MCS was 7.7% and 2.9% (P = .12) with no difference in long-term survival (P = .80), whereas patients requiring postoperative MCS had significantly increased operative (16.7%) and late mortality (63%; P <.01).

CONCLUSIONS

CABG can be performed safely in patients with ischemic cardiomyopathy with selective use of perioperative MCS. Despite advanced disease severity, patients requiring preoperative MCS demonstrate acceptable short- and long-term survival. Patients requiring postoperative MCS have increased postoperative morbidity and mortality.

Plasma SMOC2 Predicts Prognosis in Patients with Heart Failure: A Prospective Cohort

Background

Heart failure (HF) is a chronic disease with a poor prognosis, making it extremely important to assess the prognosis of patients with HF for accurate treatment. Secreted modular calcium-binding protein 2 (SMOC2) is a cysteine-rich acidic secreted protein that plays a pathophysiological role in many diseases, including regulation of vascular growth factor activity. It has previously been found that SMOC2 plays an essential role in cardiac fibrosis in our previous preclinical study, but whether it can be used as a clinical marker in heart failure patients remains unclear. The purpose of this research was to evaluate the correlation between plasma levels of SMOC2 and the prognosis for individuals with HF.

Methods

HF patients diagnosed with ischemic cardiomyopathy were enrolled from January to December 2021. Baseline plasma levels of SMOC2 were measured after demographic and clinical features were collected. Linear and nonlinear multivariate Cox regression models were used to determine the association between plasma SMOC2 and patient outcomes during follow-up. All analysis was performed using SPSS, EmpowerStats, and R software.

Results

The study included 188 patients, and the average follow-up time was 489.5±88.3 days. The plasma SMOC2 concentrations were positively correlated with N-terminal pro-B-type Natriuretic Peptide (NT-proBNP), left ventricular end-diastolic diameter (LVEDd), and length of hospital stay and were negatively correlated with left ventricular ejection fraction (LVEF) at baseline. A total of 53 patients (28.2%) were rehospitalized due to cardiac deterioration, 14 (7.4%) died, and 37 (19.7%) developed malignant arrhythmias. A fully adjusted multivariate COX regression model showed that SMOC2 is associated with readmission (HR = 1.02, 95% CI:1.012-1.655). A significant increase in rehospitalization risk was observed in group Q2 (HR =1.064, 95% CI: 1.037, 3.662, p=0.005) and group Q3 (HR =1.085, 95% CI:1.086, 3.792, p=0.009) in comparison with group Q1. The p for trend also shows a linear correlation across the three models (P < 0.001). SMOC2 was associated with the severity of HF in patients, but not with all-cause deaths and arrhythmias during follow-up.

Conclusion

Plasma SMOC2 is associated with the severity of HF and readmission rate, and is a good predictor of the risk of readmission in patients.

Choice of revascularization strategy for ischemic cardiomyopathy due to multivessel coronary disease

OBJECTIVE

Limited comparative data guide the decision between coronary artery bypass grafting and percutaneous coronary intervention for multivessel revascularization in ischemic cardiomyopathy. The study objective was to compare the long-term outcomes of coronary artery bypass grafting and percutaneous coronary intervention for ischemic cardiomyopathy.

METHODS

Clinical registries from the New Jersey Department of Health linked to administrative databases were used to compare all-cause mortality, repeat revascularization, heart failure readmissions, myocardial infarction, and stroke using Cox proportional hazards and propensity matching with competing risk analysis in 5988 patients with ejection fraction 35% or less who underwent coronary artery bypass grafting (3673, 61.3%) or percutaneous coronary intervention (2315, 38.6%) for multivessel coronary disease between 2007 and 2018. Median follow-up time was 5.2 years (range, 0-13 years); the last follow-up date was December 31, 2020.

RESULTS

After controlling for completeness of revascularization, at 13 years, mortality was 57% (95% CI, 51-63) after percutaneous coronary intervention and 60% (95% CI, 53-66) after coronary artery bypass grafting (hazard ratio [HR], 1.10; 95% CI, 0.93-1.31; P = .28); risk of repeat revascularization was 18% for percutaneous coronary intervention versus 14% for coronary artery bypass grafting (HR, 1.62; 95% CI, 1.17-2.25; P = .003); risk of readmission for heart failure was 16% after percutaneous coronary intervention and coronary artery bypass grafting (HR, 1.13,95% CI, 0.84-1.51, weighted P = .10); risk of myocardial infarction was 10% versus 6%, respectively (HR, 1.91; 95% CI, 1.18-3.09; P = .007); and stroke risk was 3% versus 4%, respectively (HR, 0.79; 95% CI, 0.41-1.53; P = .52). Rate of complete revascularization was lower after percutaneous coronary intervention than after coronary artery bypass grafting and associated with higher mortality after percutaneous coronary intervention (HR, 1.35; 95% CI, 1.20-1.52; P < .001).

CONCLUSIONS

Coronary bypass was associated with similar mortality, stroke, and heart failure readmissions, and reduced repeat revascularization compared with percutaneous coronary intervention in patients with ischemic cardiomyopathy if similar rates of complete revascularization were achieved. These findings support consensus recommendations for coronary artery bypass grafting and medical therapy in patients with multivessel coronary disease and left ventricular dysfunction.

Long-term results of surgical ventricular reconstruction and comparison with the Surgical Treatment for Ischemic Heart Failure trial

OBJECTIVE

The role of surgical ventricular reconstruction (SVR) in patients with ischemic cardiomyopathy is controversial. Observational series and the Surgical Treatment of IsChemic Heart failure (STICH) trial reported contradictory results. SVR is highly dependent on operator experience. The aim of this study is to compare the long-term results of SVR between a high-volume SVR institution and the STICH trial using individual patient data.

METHODS

Patients undergoing SVR at San Donato Hospital (Milan) were compared with patients undergoing SVR in STICH (as-treated principle) by inverse probability treatment-weighted Cox regression. The primary outcome was all-cause mortality.

RESULTS

The San Donato cohort included 725 patients, whereas the STICH cohort included 501. Compared with the STICH-SVR cohort, San Donato patients were older (66.0, lower quartile, upper quartile [Q1, Q3: 58.0, 72.0] vs 61.9 [Q1, Q3: 55.1, 68.8], P < .001) and with lower left ventricular end-systolic volume index at baseline (LVESVI: 77.0 [Q1, Q3: 59.0, 97.0] vs 80.8 [Q1, Q3: 58.5, 106.8], P = .02). Propensity score weighting yielded 2 similar cohorts. At 4-year follow-up, mortality was significantly lower in the San Donato cohort compared with the STICH-SVR cohort (adjusted hazard ratio, 0.71; 95% confidence interval, 0.53-0.95; P = .001). Greater postoperative LVESVI was independently associated with mortality (hazard ratio, 1.02; 95% confidence interval, 1.01-1.03). At 4 to 6 months of follow-up, the mean reduction of LVESVI in the San Donato cohort was 39.6%, versus 10.7% in the STICH-SVR cohort (P < .001).

CONCLUSIONS

Patients with postinfarction LV remodeling undergoing SVR at a high-volume SVR institution had better long-term results than those reported in the STICH trial, suggesting that a new trial testing the SVR hypothesis may be warranted.

Temporary mechanical circulatory support & enhancing recovery after cardiac surgery

PURPOSE OF REVIEW

This review highlights the integration of enhanced recovery principles with temporary mechanical circulatory support associated with adult cardiac surgery.

RECENT FINDINGS

Enhanced recovery elements and efforts have been associated with improvements in quality and value. Temporary mechanical circulatory support technologies have been successfully employed, improved, and the value of their proactive use to maintain hemodynamic goals and preserve long-term myocardial function is accruing.

SUMMARY

Temporary mechanical circulatory support devices promise to enhance recovery by mitigating the risk of complications, such as postcardiotomy cardiogenic shock, organ dysfunction, and death, associated with adult cardiac surgery.

Ischemic cardiomyopathy: epidemiology, pathophysiology, outcomes, and therapeutic options

Ischemic cardiomyopathy (ICM) is the most prevalent cause of heart failure (HF) in developed countries, with significant morbidity and mortality, despite constant improvements in the management of coronary artery disease. Current literature on this topic remains fragmented. Therefore, this review aimed to summarize the most recent data on ICM, focusing on its definition, epidemiology, outcomes, and therapeutic options. The most widely accepted definition is represented by a left ventricular dysfunction in the presence of significant coronary artery disease. The prevalence of ICM is largely influenced by age and sex, with older individuals and males being more affected. Its pathophysiology is characterized by plaque buildup, thrombus formation, hypoperfusion, ischemic cell death, and left ventricular remodeling. Despite improvements in therapy, ICM still represents a public health burden, with a 1-year mortality rate of 16% and a 5-year mortality rate of approximately 40% in the USA and Europe. Therefore, optimization of cardiovascular function, prevention of progressive remodeling, reduction of HF symptoms, and improved survival are the main goals of treatment. Therapeutic options for ICM include lifestyle changes, optimal medical therapy, revascularization, device therapy, mechanical circulatory support, and cardiac transplantation. Personalized management strategies and tailored patient care are needed to improve the outcomes of patients with ICM.

Programmatic approach to patients with advanced ischemic cardiomyopathy: Integrating microaxial support into strategies for the modern era

Patients with advanced ischemic cardiomyopathy manifesting as left ventricular dysfunction exist along a spectrum of severity and risk, and thus decision-making surrounding optimal management is challenging. Treatment pathways can include medical therapy as well as revascularization through percutaneous coronary intervention or coronary artery bypass grafting. Additionally, temporary and durable mechanical circulatory support, as well as heart transplantation, may be optimal for select patients. Given this spectrum of risk and the complexity of treatment pathways, patients may not receive appropriate therapy given their perceived risk, which can lead to sub-satisfactory outcomes. In this review, we discuss the identification of high-risk ischemic cardiomyopathy patients, along with our programmatic approach to patient evaluation and perioperative optimization. We also discuss our strategies for therapeutic decision-making designed to optimize both short- and long-term patient outcomes.

Long-term survival of ischemic cardiomyopathy patients with severe left ventricular dysfunction after CABG vs heart transplantation: A single center retrospective analysis

BACKGROUND

There are no guidelines on the surgical management for ischemic cardiomyopathy (ICM) patients with severe left ventricular dysfunction. The present study aims to assess the long-term survival of these patients treated with two different surgical techniques, coronary artery bypass grafting (CABG) and heart transplantation (HTx).

METHODS

This retrospective study included 218 ICM patients with left ventricular ejection fraction (LVEF) ≤35% who underwent CABG (n = 106) and HTx (n = 112) from 2011 to 2021 in a single center. After propensity adjustment analysis each group consisted of 51 patients. Clinical characteristics were evaluated for all-cause follow-up mortality by the Cox proportional hazards regression model. A risk prediction model was generated from multivariable-adjusted Cox regression analysis and applied to stratify patients with different clinical risks. The long-term survival was estimated by Kaplan-Meier analysis for different surgery groups.

RESULTS

Long-term survival was comparable between CABG and HTx groups. After being stratified into different risk subgroups according to risk predictors, the HTx group exhibited superior survival outcomes compared to the CABG group among the high-risk patients (67.8% vs 44.4%, 64.1% vs 38.9%, and 64.1% vs 33.3%, p = 0.047) at 12, 36, and 60 months respectively, while the survival was comparable between HTx and CABG groups among low-risk patients (87.0% vs 97.0%, 82.4% vs 97.0%, and 70.2% vs 91.6%, p = 0.11) at 12, 36, and 60 months respectively in the PSM cohort.

CONCLUSION

Long-term survival in ICM patients with severe left ventricular dysfunction who received CABG or HTx was comparable in general. Nonetheless, a favorable outcome of HTx surgery compared to CABG was observed among high-risk patients.

Coronary artery bypass grafting in left ventricular dysfunction: when and how

PURPOSE OF REVIEW

The surgical management of patients undergoing coronary artery bypass grafting (CABG) with low ejection fraction presents unique challenges that require meticulous attention to details and good surgical technique and judgement. This review details the latest evidence and best practices in the care of such patients.

RECENT FINDINGS

CABG in patients with low ejection fraction carries a significant risk of perioperative mortality and morbidity related to the development of postcardiotomy shock. Preoperative optimization with pharmacological or mechanical support is required, especially in patients with cardiogenic shock. Rapid and complete revascularization is what CABG surgeons aim to achieve. Multiple arterial revascularization should be reserved to selected patients. Off-pump CABG, on-pump breathing heart CABG, and new cardioplegic solutions remain of uncertain benefit compared with traditional CABG.

SUMMARY

Tremendous advancements in CABG allowed surgeons to offer revascularization to patients with severe left ventricular dysfunction and multivessel disease with acceptable risk. Despite that, there is a lack of comprehensive and robust studies particularly on long-term outcomes. Individualized patient assessment and a heart team approach should be used to determine the optimal surgical strategy for each patient.

Expert systematic review on the choice of conduits for coronary artery bypass grafting: endorsed by the European Association for Cardio-Thoracic Surgery (EACTS) and The Society of Thoracic Surgeons (STS)

PREAMBLE

The finalized document was endorsed by the EACTS Council and STS Executive Committee before being simultaneously published in the European Journal of Cardio-thoracic Surgery (EJCTS) and The Annals of Thoracic Surgery (The Annals) and the Journal of Thoracic and Cardiovascular Surgery (JTCVS).

STICH3C: Rationale and Study Protocol

BACKGROUND

Coronary artery bypass grafting (CABG) is the recommended mode of revascularization in patients with ischemic left ventricular dysfunction (iLVSD) and multivessel disease. However, contemporary percutaneous coronary intervention (PCI) outcomes have improved with the integration of novel technologies and refinement of revascularization strategies, and PCI is often used in clinical practice in this population. There is a lack of evidence from randomized trials comparing contemporary state-of-the-art PCI versus CABG for the treatment of iLVSD and multivessel disease. This was the impetus for the STICH3C trial (Canadian CABG or PCI in Patients With Ischemic Cardiomyopathy), described here.

METHODS

The STICH3C trial is a prospective, unblinded, international, multicenter trial with an expected sample size of 754 participants from ≈45 centers. Patients with multivessel/left main coronary artery disease and iLVSD with left ventricular ejection fraction ≤40% considered by the local Heart Team appropriate for and amenable to revascularization by both modes of revascularization will be randomized in a 1:1 ratio to state-of-the-art PCI or CABG.

RESULTS

The primary end point is the composite of death from any cause, stroke, spontaneous myocardial infarction, urgent repeat revascularization, or heart failure readmission, summarized as a time-to-event outcome. The key hierarchical end point is time to death and frequency of hospitalizations for heart failure. The key safety outcome is a composite of major adverse events. Disease-specific quality-of-life and health economics measures will be compared between groups. Participants will be followed for a median of 5 years, with a minimum follow-up of 4 years.

CONCLUSIONS

STICH3C will directly inform patients, clinicians, and international practice guidelines about the efficacy and safety of CABG versus PCI in patients with iLVSD. The results will provide novel and broad evidence, including clinical events, health status, and economic assessments, to guide care for patients with iLVSD and severe coronary artery disease.

REGISTRATION

URL: https://clinicaltrials.gov/; Unique identifier: NCT05427370.

Mitral Interventions in Heart Failure

Patients with heart failure with reduced ejection fraction who have secondary mitral regurgitation (SMR) have poorer outcomes and quality of life than those without SMR. Guideline-directed medical therapy is the cornerstone of SMR treatment. Careful evaluation of landmark trials using mitral transcatheter edge-to-edge repair in SMR has led to an improved understanding of who will benefit from percutaneous interventions with emphasis on a multidisciplinary approach. The success with mitral transcatheter edge-to-edge repair in SMR has also spurred the evaluation of its role in populations that were not initially studied, such as end-stage heart failure and cardiogenic shock. A spectrum of transcatheter devices in development and clinical trials promise to further provide a growing array of management options for heart failure with reduced ejection fraction patients with symptomatic SMR.

[Myocardial revascularization in chronic coronary artery disease. State of art]

The review addresses debatable issues of myocardial revascularization in chronic forms of ischemic heart disease, shows major differences between percutaneous coronary intervention and coronary artery bypass grafting in terms of long-term prognosis, and the dependence of the results on the clinical profile of the disease. The review of current publications demonstrates advantages of open surgery in long-term survival and prevention of adverse outcomes in target groups of patients.

Myocardial Revascularization in Patients With Ischemic Cardiomyopathy: For Whom and How

Background Myocardial revascularization has been advocated to improve myocardial function and prognosis in ischemic cardiomyopathy (ICM). We discuss the evidence for revascularization in patients with ICM and the role of ischemia and viability detection in guiding treatment. Methods and Results We searched for randomized controlled trials evaluating the prognostic impact of revascularization in ICM and the value of viability imaging for patient management. Out of 1397 publications, 4 randomized controlled trials were included, enrolling 2480 patients. Three trials (HEART [Heart Failure Revascularisation Trial], STICH [Surgical Treatment for Ischemic Heart Failure], and REVIVED [REVascularization for Ischemic VEntricular Dysfunction]-BCIS2) randomized patients to revascularization or optimal medical therapy. HEART was stopped prematurely without showing any significant difference between treatment strategies. STICH showed a 16% lower mortality with bypass surgery compared with optimal medical therapy at a median follow-up of 9.8 years. However, neither the presence/extent of left ventricle viability nor ischemia interacted with treatment outcomes. REVIVED-BCIS2 showed no difference in the primary end point between percutaneous revascularization or optimal medical therapy. PARR-2 (Positron Emission Tomography and Recovery Following Revascularization) randomized patients to imaging-guided revascularization versus standard care, with neutral results overall. Information regarding the consistency of patient management with viability testing results was available in ≈65% of patients (n=1623). No difference in survival was revealed according to adherence or no adherence to viability imaging. Conclusions In ICM, the largest randomized controlled trial, STICH, suggests that surgical revascularization improves patients' prognosis at long-term follow-up, whereas evidence supports no benefit of percutaneous coronary intervention. Data from randomized controlled trials do not support myocardial ischemia or viability testing for treatment guidance. We propose an algorithm for the workup of patients with ICM considering clinical presentation, imaging results, and surgical risk.

[Cardioanaesthesiology - What's new?]

The still unchanged high morbidity and mortality of patients undergoing complex cardiac surgical procedures as well as developments in minimally invasive cardiac surgery are not only an ongoing challenge for all working in cardiac anaesthesia but also a chance for further developing this anaesthetic subdiscipline. Alongside the presentation of a case report, the present article gives an overview about recent developments in inotropic therapy, monitoring, the rational use of mechanical circulatory support, volume therapy, sedation, analgesia, and point-of-care coagulation monitoring in cardiac anaesthesia.

Association of serum anion gap and risk of long-term mortality in patients following coronary artery bypass grafting: A propensity score matching study

BACKGROUND

The present study aimed to explore the relationship between serum anion gap (AG) and long-term mortality in patients undergoing coronary artery bypass grafting (CABG).

METHODS

Clinical variables were extracted among patients undergoing CABG from Medical Information Mart for Intensive Care III (MIMIC III) database. The primary outcome was 4-year mortality following CABG. An optimal cut-off value of AG was determined by the receiver operating characteristic (ROC) curve. The Kaplan-Meier (K-M) analysis and multivariate Cox hazard analysis were performed to investigate the prognostic value of AG in long-term mortality after CABG. To eliminate the bias between different groups, propensity score matching (PSM) was conducted to validate the findings.

RESULTS

The optimal cut-off value of AG was 17.00 mmol/L. Then a total of 3162 eligible patients enrolled in this study were divided into a high AG group (≥17.00, n = 1022) and a low AG group (<17.00, n = 2,140). A lower survival rate was identified in the high AG group based on the K-M curve (p < .001). Compared with patients in the low AG group, patients in the high AG group had an increased risk of long-term mortality [1-year mortality: hazard ratio, HR: 2.309, 95% CI (1.672-3.187), p < .001; 2-year mortality: HR: 1.813, 95% CI (1.401-2.346), p < .001; 3- year mortality: HR: 1.667, 95% CI (1.341-2.097), p < .001; 4-year mortality: HR: 1.710, 95% CI (1.401-2.087), p < .001] according to multivariate Cox hazard analysis. And further validation of above results was consistent in the matched cohort after PSM.

CONCLUSIONS

The AG is an independent predictive factor for long-term all-cause mortality in patients following CABG, where a high AG value is associated with an increased mortality.

Retrospective, observational analysis of cardiac function associated with global preoperative myocardial scar in patients with ischemic cardiomyopathy after coronary artery bypass grafting

BACKGROUND

Drawing on accumulated patient data from a hospital database, the goal of this retrospective study was to analyze cardiac function associated with global preoperative myocardial scarring assessed by cardiac magnetic resonance with late gadolinium enhancement (CMR-LGE) in patients with ischemic cardiomyopathy (ICM) after coronary artery bypass grafting (CABG).

METHODS

A total of 57 patients diagnosed with ICM who underwent isolated CABG at Beijing Anzhen Hospital between September 2017 and September 2019 were enrolled in this retrospective study. All these patients underwent a preoperative CMR-LGE examination. Based on postoperative echocardiography results at 6 months, cases were divided into the following 2 groups: improved cardiac function [a difference of left ventricular ejection fraction (LVEF) greater than or equal to 5%] and unimproved cardiac function. The factors contributing to these patients' unimproved cardiac function were investigated.

RESULTS

At 6 months after surgery, 64.9% (37/57) of cases had improved cardiac function, and 35.1% (20/57) had no improvement. There was no statistical difference between the 2 groups in the Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) score (41.7±7.6 vs. 42.8±8.3; P=0.603), but compared to the improved group, preoperative myocardial scarring was significantly enlarged in the unimproved group (41.9%±6.4% vs. 27.8%±8.5%; P<0.001). In regression analysis, only preoperative myocardial scarring [odds ratio (OR) =1.44; 95% confidence interval (CI): 1.13-1.83; P=0.003] was associated with no change in cardiac function evaluated by echocardiography after CABG. The median follow-up of 1.6 years (range, 0.6-4.1 years) found that the unimproved group had a higher incidence of major adverse cardiovascular and cerebrovascular events (MACCEs) (8.1% vs. 25.0%; P=0.044), and that the New York Heart Association (NYHA) classification of the unimproved group was higher than that of the improved group (P=0.018).

CONCLUSIONS

In ICM patients, a greater amount of preoperative myocardial scarring is associated with unimproved cardiac function after CABG. The measurement of preoperative myocardial scarring may aid clinicians in identifying patients who would benefit from CABG.

The Relationship Between Plasma Selenium, Antioxidant Status, Inflammatory Responses and Ischemic Cardiomyopathy: A Case-Control Study Based on Matched Propensity Scores

Background

Ischemic cardiomyopathy (ICM) with high morbidity and mortality is closely associated with an abnormal equilibrium of circulation selenium levels. The oxidative stress theory is the most accepted theory of selenium causing ischemic cardiomyopathy. However, the role of inflammatory responses in ICM has received limited attention.

Methods

This study included 119 subjects, 43 of whom were patients with ICM, and 76 were healthy controls. Blood specimens were collected from subjects and serum levels of inflammatory and oxidative stress indicators and plasma levels of selenium were measured.

Results

When plasma selenium and indicators of inflammation and oxidative stress were compared between groups, plasma selenium levels were significantly lower in the ICM group than in the control group (68.83874 vs 104.39775, p=0.02032), while indicators of inflammation such as tumour necrosis factor-alpha (TNF-α) (79.09773 vs 46.15634, p<0.001), interleukin-6 (IL-6) (49.41484 vs 38.46923, p<0.01) and neutrophil/lymphocyte ratio (3.696574 vs 2.383658, p<0.001) were significantly higher in the ICM group than in the control group (all of these results were statistically different). Additionally, malondialdehyde (MDA), a marker of oxidative stress, was considerably higher in the ICM group than in the control group (61.63078 vs 39.0609, p<0.01). In contrast, there were no significant differences in superoxide dismutase (SOD) levels between groups (p>0.05). The Poisson regression analysis revealed a significant association between selenium and high levels of MDA, IL-6 and TNF-α (p<0.05). Additionally, selenium was negatively connected with SOD levels and the neutrophil/lymphocyte ratio, but this relationship was not statistically significant (p=0.96, 0.15, respectively).

Conclusion

Selenium deficiency is strongly associated with the development of ICM, and with levels of inflammation and oxidative stress in patients with ICM. Selenium can prevent the development and delay the progression of ICM by alleviating inflammatory responses.

Friction in Myocardial Anoxia Leads to Negative Excess Entropy Production, Self-Organization, and Dissipative Structures

Contraction of the heart is caused by actin filaments sliding along myosin filaments. This generates a frictional force inducing wear of the contractile apparatus. We postulated that this process could be exacerbated when the heart was submitted to severe anoxia. Anoxia induced dramatic abnormalities in the molecular properties of actin-myosin crossbridges. We applied the formalism of far-from-equilibrium thermodynamics to the left ventricular papillary muscles (LVPMs) of mammalian rat hearts which had been subjected to a prolonged anoxia (3 h). We showed that when subjected to prolonged anoxia, the heart operated far-from-equilibrium as evidenced by the non-linearity between thermodynamic force (F/T: Frictional force/Kelvin temperature) and thermodynamic flow (v0: myofilament sliding velocity). The rate of entropy production (EPR) was the product of (F/T) and v0. The excess entropy production (EEP) was equal to ∂δ2S∂t = ∂FTδvo; (S: entropy). The tribological system remained stable when EEP was positive and became unstable when EEP became negative, thus characterizing instability of the system and reflecting the occurrence of self-organization and possibly dissipative structures. After 3 h anoxia, re-oxygenation induced significant reversibility. About 20% of the myosin heads did not recover despite re-oxygenation. These results may be of importance in the context of heart transplantation where the delay between the time of sampling from the donor and the time of the graft installation in the recipient should be as short as possible.