ESC Joint Working Groups on Cardiovascular Surgery and the Cellular Biology of the Heart Position Paper: Perioperative myocardial injury and infarction in patients undergoing coronary artery bypass graft surgery

Symptomatic early coronary graft failure in bypass surgery patients: incidence, predictors and clinical impact

OBJECTIVES

Coronary graft failure (CGF) may occur early after coronary bypass graft surgery (CABG). The study aimed to identify clinical and perioperative risk factors and to evaluate the long-term clinical impact of symptomatic early CGF.

METHODS

Patients who underwent clinically indicated coronary angiography (CAG) prior to post-CABG discharge between 2012 and 2022 were included. Symptomatic early CGF was defined as a dysfunctional coronary graft, evaluated on clinically indicated CAG, caused by stenosis of the proximal or distal anastomosis or bypass conduit, bypass occlusion, thrombosis, reduced flow (TIMI < 1) and kinking/tenting. Patients were divided into symptomatic early CGF and non-early CGF groups. Kaplan-Meier and multivariate analysis estimated cumulative survival free of major adverse cardiovascular events (MACE: death, myocardial infarction and revascularisation) up to 5 years' follow-up and identified predictors of symptomatic early CGF.

RESULTS

A total of 92 patients (79% male, 66.1 ± 10 years old) were included, of whom 55 (59.8%) had symptomatic early CGF. Baseline characteristics, surgical parameters and post-surgical parameters potentially indicative of ischaemia were comparable between groups. Patients with symptomatic early CGF had a significantly lower MACE rate over a median follow-up period of 33 months (p = 0.023). Venous graft integration (p = 0.005), Y‑graft configuration (p = 0.002) and prolonged inotropic support (p = 0.032) were associated with symptomatic early CGF.

CONCLUSIONS

Symptomatic early CGF was observed in the majority of post-CABG patients undergoing clinically indicated CAG prior to discharge. Patients with symptomatic early CGF exhibited higher MACE rates over a median follow-up period of 33 months. Venous graft integration, Y‑graft configuration and prolonged use of inotropic agents were associated with symptomatic early CGF. However, these clinical findings should be interpreted with caution.

The Clinical Significance of PCI-Related Myocardial Infarction in Stable Ischaemic Heart Disease Patients in the Era of hs-Troponin

BACKGROUND & AIM

The definition and clinical relevance of percutaneous coronary intervention (PCI)-related myocardial infarction (MI) has been a topic of significant debate and controversy. It has particularly garnered widespread attention recently due to a contemporary trend of including it as a component of primary end points in major trials. The study aimed to assess the clinical relevance of PCI-related MI (PMI) according to the Fourth Universal Definition of MI using a high-sensitivity troponin (hs-Tn) assay in a real-world setting.

METHODS

This was a single centre, retrospective registry analysis of consecutive patients who underwent elective PCI for stable ischaemic heart disease between January 2014 to December 2018. The primary end point was major adverse cardiovascular events (MACEs)-the composite of death, spontaneous MI, stent thrombosis and the need for repeat revascularisation within 12 months from the index procedure.

RESULTS

We treated 858 patients with a mean age of 67.6 years and 78.3% were men. The incidence of PMI in our cohort was 12.8%. On univariable analysis, contrast volume >150 mL, prior coronary artery bypass graft, final thrombolysis in MI flow 0-2, total stent length and stent length >20 mm were significantly associated with increased risk of PMI. There were 46 (5.4%) MACE in total with seven (6.4%) in the PMI group and 39 (5.2%) in the non-PMI group (p=0.6). Kaplan-Meier survival curves were used to estimate 1-year MACE-free survival for the patients with PMI versus non-PMI and there was no significant difference. On multivariable Cox proportional hazards analysis, contrast volume >150 mL, prior coronary artery bypass graft and estimated glomerular filtration rate <60 (mL/min/1.73 m2) were independent predictors of MACE during 1-year follow-up, whereas PMI was not an independent predictor.

CONCLUSIONS

PMI defined according to the Fourth Universal Definition of MI and using hs-Tn was common, occurring in 12.8% of patients, but not independently predictive of MACE in 1 year. As PMIs are increasingly used as a component of composite primary end points in major, practice-changing trials, establishing a clinically relevant definition of PMI is of utmost importance.

Urgent Coronary Angiography Following Cardiac Surgery: Insights from a High-Volume Cardiac Surgery Center

BACKGROUND

Post-operative myocardial infarction is a possible complication following cardiac surgery. Data on the incidence, predictors and prognosis of urgent coronary angiography (UCA) after cardiac surgery are scarce.

AIMS (OBJECTIVES)

This study aims to report in hospital and 1-year follow-up outcomes of a recent large cohort of patients undergoing UCA after cardiac surgery.

METHODS

This study provides a retrospective analysis of an high volume cardiac center (Maria Cecilia Hospital, Italy), from 2016 to 2021 regarding patients treated with coronary artery bypass grafting (CABG), valve, or aortic root surgery, focusing on those who required UCA within the same hospitalization.

RESULTS

Out of 6505 cardiac surgeries, 119 patients (1.83%) underwent UCA, with a median age of 69 years. The study found that UCA was more frequent post-CABG (2.62%) than non-CABG interventions (1.35%, p < 0.001). A graft failure was detected in 31.1% of the cases, while a native vessel complication in 36.1%. The leading reasons for UCA included ST/T abnormalities, ventricular arrhythmias, and hemodynamic instability, with 92% of UCAs performed within a week post-surgery. The in-hospital mortality rate was 32%, with no significant difference between CABG and non-CABG patients. Predictive factors for in-hospital mortality included Euroscore II, hemodynamic instability and late UCA. One-year follow-up showed a low mortality rate (2.5%) among discharged patients.

CONCLUSION

UCA resulted to have a pivotal role in detecting coronary complications after cardiac surgery, guiding subsequent treatment decisions. Despite the high in-hospital mortality rate, survival showed an overall low mortality at the 1-year mark.

Investigating outcomes of coronary artery bypass graft (CABG) surgery: a single-center retrospective study in Jordan

BACKGROUND

Coronary artery bypass graft (CABG) surgery brings significant cardiac benefits but also risks post-operative complications, including cognitive impairments and infections.

MATERIALS & METHODS

We analyzed 108 patient records between 2011 and 2021 at the Princess Muna Al-Hussein Cardiac Center, Irbid, Jordan. The primary endpoint was the occurrence of postoperative events.

RESULTS

Few patients (8.3%) faced complications like stroke and infections, with age and ICU stay length as significant risk factors. Patients with complications often experienced left ventricular impairments and required inotropic support.

CONCLUSION

The study highlights the need for understanding CABG surgery complications to improve outcomes, emphasizing preventive care and personalized follow-up.

Impact of High-Sensitivity Cardiac Troponin I Elevation After On- and Off-Pump Coronary Artery Bypass Grafting on Long-Term Prognosis

BACKGROUND

Postoperative myocardial injury is correlated with long-term prognosis after coronary artery bypass grafting (CABG) and is diagnosed according to troponin levels, which vary substantially upon surgical strategies. We aimed to explore the troponin I cutoff values for prognostically significant myocardial injury separately in on-pump and off-pump procedures with the use of a high-sensitivity assay (hs-cTnI).

METHODS

Patients who underwent isolated CABG from 2018 to 2020 with available perioperative hs-cTnI measurements were included in this study. We explored the relationships between hs-cTnI levels and different outcomes. To identify hs-cTnI threshold levels indicative of higher risks, restrictive spline regressions were performed for on-pump and off-pump procedures.

RESULTS

A total of 7813 patients were included with a median follow-up of 2.7 years (interquartile range 1.7-3.3 years), 218 (2.8%) of whom died. Adjusting for clinical variables, the study found a significant association between peak hs-cTnI levels within the first 48 hours after surgery and all end points. The spline regressions demonstrated that the hs-cTnI levels measured within 48 hours after surgery that were associated with a hazard ratio of more than 1.00 for all-cause death were 1446 ng/L (55.6 × upper reference limit [URL], 95% confidence interval [CI] 45.0-106.5 × URL) for on-pump and 564 ng/L (21.7 × URL, 95% CI 21.0-30.2 × URL) for off-pump.

CONCLUSIONS

Elevated hs-cTnI levels after CABG were associated with poorer longer-term outcomes. A prognosis-relevant hs-cTnI cutoff value within 48 hours after CABG for on-pump is significantly higher than that for off-pump.

Anti-inflammatory effect of colchicine on organ damage during the perioperative period of cardiac surgery: a study protocol for a multicentre, randomised, double-blind, placebo-controlled clinical trial

INTRODUCTION

The systemic inflammatory response syndrome during the perioperative period of cardiac surgery can lead to serious postoperative complications and significantly increase the hospital mortality rate. Colchicine, a widely used traditional anti-inflammatory drug, has good clinical value in cardiovascular anti-inflammatory therapy. Our preliminary single-centre study had confirmed the protective value of colchicine in patients undergoing cardiac surgery with cardiopulmonary bypass. For this multicentre investigation, we aim to further validate the anti-inflammatory and organ-protective effects of low-dose colchicine during the perioperative period in a low-risk population.

METHODS AND ANALYSIS

This study is a multicentre, randomised, double-blind, placebo-controlled clinical trial. A total of 768 patients undergoing elective cardiac surgery will be enrolled from eight heart centres in China. The participants will be randomly assigned to two groups: the colchicine group will receive low-dose colchicine (0.5 mg once-a-day dosing regimen (QD) orally for 3 days before the surgery and 0.5 mg dosing frequency of every other day (QOD) continuously for 10 days after the surgery), whereas the placebo group will be given starch tablets for the same time and dosage. Primary endpoints are the occurrence of postoperative inflammatory diseases, including postoperative atrial fibrillation, acute respiratory distress syndrome, preoperative myocardial injury and post-pericardiotomy syndrome. Secondary endpoints included laboratory tests on postoperative days 1, 3, 5, 7 and 10, intensive care unit data, APACHE II score, Murray lung injury score, medication-related gastrointestinal reactions, 30-day and 90-day all-cause mortality, surgical data, chest radiograph on postoperative days 1, 2 and 3, and chest CT within 14 days after surgery.

ETHICS AND DISSEMINATION

This research has received approval from the Medical Ethics Committee of Affiliated Nanjing Drum Tower Hospital, Nanjing University Medical College (approval number 2023-366-01). The study findings will be made available by publishing them in an open access journal.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT06118034).

Coronary sodium [18F]fluoride activity predicts outcomes post-CABG: a comparative evaluation with conventional metrics

PURPOSE

The value of preoperative multidisciplinary approach remains inadequately delineated in forecasting postoperative outcomes of patients undergoing coronary artery bypass grafting (CABG). Herein, we aimed to ascertain the efficacy of multi-modality cardiac imaging in predicting post-CABG cardiovascular outcomes.

METHODS

Patients with triple coronary artery disease underwent cardiac sodium [18F]fluoride ([18F]NaF) positron emission tomography/computed tomography (PET/CT), coronary angiography, and CT-based coronary artery calcium scoring before CABG. The maximum coronary [18F]NaF activity (target-to-blood ratio [TBR]max) and the global coronary [18F]NaF activity (TBRglobal) was determined. The primary endpoint was perioperative myocardial infarction (PMI) within 7-day post-CABG. Secondary endpoint included major adverse cardiac and cerebrovascular events (MACCEs) and recurrent angina.

RESULTS

This prospective observational study examined 101 patients for a median of 40 months (interquartile range: 19-47 months). Both TBRmax (odds ratio [OR] = 1.445; p = 0.011) and TBRglobal (OR = 1.797; P = 0.018) were significant predictors of PMI. TBRmax>3.0 (area under the curve [AUC], 0.65; sensitivity, 75.0%; specificity, 56.8%; p = 0.036) increased PMI risk by 3.661-fold, independent of external confounders. Kaplan-Meier test revealed a decrease in MACCE survival rate concomitant with an escalating TBRmax. TBRmax>3.6 (AUC, 0.70; sensitivity, 76.9%; specificity, 73.9%; p = 0.017) increased MACCEs risk by 5.520-fold. Both TBRmax (hazard ratio [HR], 1.298; p = 0.004) and TBRglobal (HR = 1.335; p = 0.011) were significantly correlated with recurrent angina. No significant associations were found between CAC and SYNTAX scores and between PMI occurrence and long-term MACCEs.

CONCLUSION

Quantification of coronary microcalcification activity via [18F]NaF PET displayed a strong ability to predict early and long-term post-CABG cardiovascular outcomes, thereby outperforming conventional metrics of coronary macrocalcification burden and stenosis severity.

TRIAL REGISTRATION

The trial was registered with the Chinese Clinical Trial Committee (number: ChiCTR1900022527; URL: www.chictr.org.cn/showproj.html?proj=37933 ).

Comparison between Off-Pump and On-Pump Beating Heart Coronary Artery Bypass Grafting

BACKGROUND

 Although coronary artery bypass grafting (CABG) is performed via three different techniques, conventional, on-pump beating heart CABG (ONBHCAB), or off-pump CABG (OPCAB), data are limited to compare ONBHCAB with OPCAB.

METHODS

 We retrospectively investigated the postoperative cardiac biomarkers, creatine kinase-MB (CK-MB), and troponin I (cTnI), and early and late outcomes in 806 patients undergoing isolated ONBHCAB or OPCAB between February 2008 and September 2022. To eliminate the bias between different groups, propensity score matching was conducted to validate the findings.

RESULTS

 After matching, the number of each study group totaled 270 patients. In both complete and matched cohorts, early outcomes, including morbidities and mortalities, were similar. However, cTnI and CK-MB levels were significantly higher after ONBHCAB than after OPCAB with median peak cTnI of 9.85 versus 4.60 ng/mL and median peak CK-MB of 48.45 versus 17.10 ng/mL in the matched cohort, which were quite low, below the threshold for values defining perioperative myocardial infarction. At follow-up of 73 ± 45 months, the overall actuarial survival rates were similar between the ONBHCAB and OPCAB patients (86 vs. 87% at 5 years and 64 vs. 68% at 10 years, respectively, in the matched cohort).

CONCLUSION

 ONBHCAB may be a comparable alternative to OPCAB with similar early and late outcomes, despite higher elevation of postoperative cardiac biomarkers. ONBHCAB provides more efficient hemodynamic support, providing a better surgical visual field, than OPCAB while reducing the risk of incomplete revascularization.

Modeling creatine-kinase MB concentrations following coronary artery bypass grafting

BACKGROUND

An increase in cardiac biomarkers is a prerequisite for diagnosing periprocedural myocardial infarction (PMI) after coronary artery bypass grafting (CABG). Early-phase risk detection may be aided by modeling time-dependent serum creatine kinase-MB (CK-MB) concentrations. This study aimed to model the kinetics of CK-MB while identifying its influencing factors.

METHODS

Patients who underwent elective CABG and had CK-MB measurements within 72 hours postoperatively were included. The primary outcome was the modeled post hoc kinetics of CK-MB in patients without potential PMI. These patients were defined as having no potential PMI based on the absence of ischemic electrocardiographic abnormalities, imaging abnormalities, in-hospital cardiac arrest, mortality, or postoperative unplanned catheterization. A web-based application was created using mixed-effect modeling to provide an interactive and individualized result.

RESULTS

A total of 1589 CK-MB measurements from 635 patients who underwent elective isolated CABG were available for analysis. Of these, 609 patients (96%) had no potential PMI and 26 (4%) had potential PMI. Male sex, aortic cross-clamp time, and cardioplegia type significantly impacted CK-MB concentrations. The diagnostic accuracy of the model had an area under the receiver operating characteristic curve of 82.8% (95% confidence interval, 72.6%-90.2%). A threshold of 7 μg/L yielded a sensitivity of 94% and a specificity of 80% (positive predictive value, 17%; negative predictive value, 99%) for excluding potential PMI in our study population.

CONCLUSIONS

CK-MB release after CABG depends on the timing of measurement, patient sex, aortic cross-clamp time, and cardioplegia type. The model (available at https://www.cardiomarker.com/ckmb) can be validated, reproduced, refined, and applied to other biomarkers.

The prognostic impact of unplanned invasive coronary angiography following coronary artery bypass grafting

OBJECTIVES

Myocardial ischaemia following coronary artery bypass grafting (CABG) is a potentially devastating complication. Nevertheless, the incidence, aetiology and prognostic relevance of unplanned coronary angiography (uCAG) remain understudied. We aimed to investigate the prevalence and outcome of patients undergoing urgent, uCAG in the postoperative period following CABG.

METHODS

We screened all patients undergoing isolated elective CABG in an academic referral centre between 2016 and 2021 and identified patients undergoing uCAG within 30 days of surgery. For uCAG patients, a distinction was made between patients undergoing re-revascularization (REV) and patients receiving conservative management (CON). The primary outcomes were 30-day mortality and unadjusted and adjusted long-term survival. Secondary outcomes were the indication for and prevalence of uCAG and urgent revascularization.

RESULTS

Of the 1918 patients undergoing isolated CABG, 78 individuals needed uCAG (4.1%), of whom 45 underwent immediate revascularization (REV group; 2.3% overall, 57% within the uCAG group, median age 69.9 years) and 33 were treated conservatively (CONS group; 1.7% overall, 42% within the uCAG group, median age 69.1 years). Patients undergoing uCAG (n = 78) had a higher 30-day mortality than patients not undergoing uCAG (n = 1840, 30-day mortality: 9.0% vs 0.4%, P < 0.001). Long-term survival was significantly decreased in patients undergoing uCAG in both unadjusted (hazard ratio 2.20, 95% confidence interval 1.30-3.73) and EuroSCORE-, age- and sex-adjusted models (hazard ratio uCAG 2.03, 95% confidence interval 1.16-3.56).

CONCLUSIONS

Unplanned postoperative coronary angiography is performed in 4.1% of isolated CABG procedures, and patients in need of such urgent invasive evaluation are subjected to decreased short- and long-term survival.

Cardioprotection in cardiovascular surgery

Since the invention of cardiopulmonary bypass, cardioprotective strategies have been investigated to mitigate ischemic injury to the heart during aortic cross-clamping and reperfusion injury with cross-clamp release. With advances in cardiac surgical and percutaneous techniques and post-operative management strategies including mechanical circulatory support, cardiac surgeons are able to operate on more complex patients. Therefore, there is a growing need for improved cardioprotective strategies to optimize outcomes in these patients. This review provides an overview of the basic principles of cardioprotection in the setting of cardiac surgery, including mechanisms of cardiac injury in the context of cardiopulmonary bypass, followed by a discussion of the specific approaches to optimizing cardioprotection in cardiac surgery, including refinements in cardiopulmonary bypass and cardioplegia, ischemic conditioning, use of specific anesthetic and pharmaceutical agents, and novel mechanical circulatory support technologies. Finally, translational strategies that investigate cardioprotection in the setting of cardiac surgery will be reviewed, with a focus on promising research in the areas of cell-based and gene therapy. Advances in this area will help cardiologists and cardiac surgeons mitigate myocardial ischemic injury, improve functional post-operative recovery, and optimize clinical outcomes in patients undergoing cardiac surgery.

External stenting for saphenous vein grafts reduces early postoperative graft failure

OBJECTIVES

Multiple studies have shown that external stenting (ExSt) mitigates the progression of vein graft disease years after coronary artery bypass grafting (CABG). We used computed tomography to evaluate the effect of ExSt on perioperative vein graft patency.

METHODS

This study assessed graft patency rates of saphenous vein grafts (SVG) in consecutive patients with isolated coronary artery bypass grafting (CABG) between 2018 and 2021. Logistic regression analyses were conducted to compare the outcomes of supported and non-supported groups at both patient and graft levels, with age, EuroSCORE II, gender, diabetes and arterial grafts as covariates. Subgroup analyses were performed based on different covariates. The goal of the study was to provide valuable insights into the clinical outcomes of SVG in patients having CABG.

RESULTS

The study examined a total of 357 patients who met the inclusion criteria and evaluated 572 vein grafts. Of these, 150 patients (205 SVGs) received ExSt, whereas 207 patients (337 SVGs) did not receive ExSt. The study results indicated that the likelihood of overall SVG patency at discharge was higher in the stented group than in the non-stented group, both at the level of the grafts [93.8% vs 87.8%, odds ratio (OR) 2.1; 95% confidence interval (CI) 1.0-4.5; P = 0.05] and at the patient level (90.1% vs 83.5%, OR 1.8; 95% CI 0.9-3.6; P = 0.1). It is worth noting that the difference between the stented and non-stented groups was most significant in the subgroup that received 2 arterial grafts (96.5% vs 89.6%, OR 3.2; 95% CI 1.2-8.4; P = 0.02) and in the subgroup with a higher EuroSCORE II (median >1.1) (98.6% vs 88.6%, OR 8.8; 95% CI 1.1-72.7; P = 0.04).

CONCLUSIONS

The ExSt is associated with improved perioperative SVG patency at both the graft and the patient levels. Moreover, SVGs to the right territory and high-risk patients appear to have an advantage using ExSt.

Drug-eluting balloon to treat immediate post-coronary artery bypass grafting ST-elevation myocardial infarction: a case report

Background

Coronary artery bypass graft (CABG) surgery represents a major cardiovascular operation and may be associated with post-operative ST-elevation myocardial infarction (STEMI) due to graft failure. This is challenging to diagnose and treat as the implanted grafts may be prone to complications when treated percutaneously with drug-eluting stents.

Case summary

A man in his 60 s underwent CABG and developed new persistent ST elevations of 2 mm in anterior leads with no significant chest pain, although, administered with intravenous opiates post-operatively. Transthoracic echocardiography was non-diagnostic. Invasive angiography performed emergently showed a thrombotic occlusion of the mid-left anterior descending artery at the site of the anastomosis with the left internal mammary artery (LIMA) graft. Intervention via the graft was considered high risk of complications, therefore, native coronary arteries were used to approach the occlusion, which was successfully cleared with a combination balloon angioplasty with a semi-compliant and then a drug-eluting balloon. The LIMA started working again with the resolution of ST elevation and no immediate complications.

Discussion

Early post-operative ST elevations in continuous leads should not be ignored as they often may be the only feature of new-onset STEMI. Drug-eluting balloons represent a feasible and possibly safer option than drug-eluting stents to treat these conditions.

Periprocedural myocardial infarction and injury

Periprocedural myocardial infarction (PMI) and injury, pertinent to both cardiac and non-cardiac procedures, have gained increasing recognition in clinical practice. Over time, diverse definitions for diagnosing PMI have been developed and validated among patient populations undergoing coronary revascularization. However, this variety in definitions presents considerable challenges in clinical settings and complicates both the design and interpretation of clinical trials. The necessity to accurately diagnose PMI has spurred significant interest in establishing universally accepted and prognostically meaningful thresholds for cardiac biomarkers elevation and supportive ancillary criteria. In fact, elevations in cardiac biomarkers in line with the 4th Universal Definition of Myocardial Infarction, have been extensively confirmed to be associated with increased mortality and cardiovascular events. In the context of non-coronary cardiac procedures, such as Transcatheter Aortic Valve Implantation, there is a growing acknowledgment of both the high incidence rates and the adverse impact of PMI on patient outcomes. Similarly, emerging research underscores the significance of PMI and injury in non-cardiac surgery, highlighting the urgent need for effective prevention and risk management strategies in this domain.

Selenoprotein P-1 (SEPP1) as an Early Biomarker of Myocardial Injury in Patients Undergoing Cardiopulmonary Bypass

Background: Biomarkers development for prognostication or prediction of perioperative myocardial disease is critical for the evolution of treatment options in patients undergoing cardiac surgery. The aim of our prospective monocentric study was to investigate the role of selenoprotein 1 (SEEP 1) as a potential biomarker for assessing the risk of myocardial injury after cardiac surgery. Methods: Circulating SEPP1 was measured in the blood of 45 patients before surgery and at 4 h, 8 h and 12 h after CPB by enzyme-linked immunosorbent assay (ELISA); (3) Results: circulating SEPP-1 levels measured 4 h after surgery were strongly correlated with CK-MB levels measured at 48 h (R = 0.598, p < 0.0001) and at 72 h (R = 0.308, p = 0.05). Close correlations were also found between 4 h SEPP-1 and Hs-c troponin values measured at 24 h (R = 0.532, p < 0.0001), 48 h (R = 0.348, p = 0.01) and 72 h (R = 0.377, p = 0.02), as well as with cardiopulmonary bypass (CPB) (R = 0.389, p = 0.008) and cross-clamp time (R = 0.374, p = 0.001); (4) Conclusions: Early SEPP1 measurement after CPB may hold great potential for identifying cardiac surgery patients at risk of developing perioperative myocardial injury.

Evaluation of the Patients with Recurrent Angina After Coronary Artery Bypass Grafting

INTRODUCTION

In this study, we aimed to evaluate the most common causes of recurrent angina after coronary artery bypass grafting (CABG) and our treatment approaches applied in these patients.

METHODS

We included all patients who underwent CABG, with or without percutaneous coronary intervention after CABG, at our hospital from September 2013 to December 2019. Patients were divided into two groups according to the time of onset of anginal pain after CABG. Forty-five patients (58.16 ± 8.78 years) had recurrent angina in the first postoperative year after CABG and were specified as group I (early recurrence). Group II (late recurrence) comprised 82 patients (58.05 ± 8.95 years) with angina after the first year of CABG.

RESULTS

The mean preoperative left ventricular ejection fraction was 53.22 ± 8.87% in group I, and 54.7 ± 8.58% in group II (P=0.38). No significant difference was registered between groups I and II regarding preoperative angiographic findings (P>0.05). Failed grafts were found in 27.7% (n=28/101) of the grafts in group I as compared to 26.8% (n=51/190) in group II (P>0.05). Twenty-four (53.3%) patients were treated medically in group I, compared with 54 (65.8%) patients in group II (P=0.098). There was a need for intervention in 46.6% (n=21) of group I patients, and in 34.1% (n=28) of group II patients.

CONCLUSION

Recurrent angina is a complaint that should not be neglected because most of the patients with recurrent angina are diagnosed with either native coronary or graft pathology in coronary angiography performed.

Right Heart Reverse Remodeling and Prosthetic Valve Function After Transcatheter vs Surgical Pulmonary Valve Replacement

BACKGROUND

There are limited data about postprocedural right heart reverse remodeling and long-term prosthesis durability after transcatheter pulmonary valve replacement (TPVR) and how these compare to surgical pulmonary valve replacement (SPVR).

OBJECTIVES

This study sought to compare right heart reverse remodeling, pulmonary valve gradients, and prosthetic valve dysfunction after TPVR vs SPVR.

METHODS

Patients with TPVR were matched 1:2 to patients with SPVR based on age, sex, body surface area, congenital heart lesion, and procedure year. Right heart indexes (right atrial [RA] reservoir strain, RA volume index, RA pressure, right ventricular [RV] global longitudinal strain, RV end-diastolic area, and RV systolic pressure) were assessed at baseline (preintervention), 1 year postintervention, and 3 years postintervention. Pulmonary valve gradients were assessed at 1, 3, 5, 7, and 9 years postintervention.

RESULTS

There were 64 and 128 patients in the TPVR and SPVR groups, respectively. Among patients with TPVR, 46 (72%) and 18 (28%) received Melody (Medtronic) vs SAPIEN (Edwards Lifesciences) valves, respectively. The TPVR group had greater postprocedural improvement in RA reservoir strain and RV global longitudinal strain at 1 and 3 years. The TPVR group had a higher risk of prosthetic valve dysfunction mostly because of a higher incidence of prosthetic valve endocarditis compared to SPVR but a similar risk of pulmonary valve reintervention because some of the patients with endocarditis received medical therapy only. Both groups had similar pulmonary valve mean gradients at 9 years postintervention.

CONCLUSIONS

These data suggest a more favorable right heart outcome after TPVR. However, the risk of prosthetic valve endocarditis and prosthetic valve dysfunction remains a major concern.

Comparison of Bretschneider HTK and Blood Cardioplegia (4:1): A Prospective Randomized Study

BACKGROUND

We compared the effect of intermittent blood and histidine-tryptophan-ketoglutarate (HTK) solution of Bretschneider on myocardial histopathology and perioperative outcome.

METHODS

Forty adult cardiac surgery patients were grouped into two (n = 20 for each): (1) Intermittent blood cardioplegia (IBC): had repeated cold 4:1 blood cardioplegia and (2) HTK: had a single dose of cold HTK for cardioprotection. Creatine kinase (CK)-MB, Troponin-I (cTn-I), pH, and lactate were studied in coronary sinus blood before and after aortic cross-clamping (AXC) and systemic blood at postoperative 6th, 24th, and 48th hours. Myocardial biopsy was performed before and after AXC for light microscopy. Vacuolation, inflammation, edema, and glycogen were graded semiquantitatively (from 0 to 3). The myocardial apoptotic index was evaluated via the terminal deoxynucleotidyl transferase dUTP nick end labeling.

RESULTS

There were no differences in perioperative clinical outcomes between the groups. The coronary sinus samples after AXC were more acidotic (7.15 ± 0.14 vs. 7.32 ± 0.07, p = 0.001) and revealed higher CK-MB (21.0 ± 12.81 vs. 12.60 ± 11.80, p = 0.008) in HTK compared with IBC. The HTK had significantly a higher amount of erythrocyte suspension intraoperatively compared with IBC (0.21 ± 0.53 vs. 1.68 ± 0.93 U, p = 0.001). Microscopically, myocardial edema was more pronounced in HTK compared with IBC after AXC (2.25 ± 0.91 vs. 1.50 ± 0.04, p = 0.013). While a significant increase in the apoptotic index was seen after AXC in both groups (p = 0.001), no difference was detected between the groups (p = 0.417).

CONCLUSION

IBC and HTK have a similar clinical outcome and protective effect, except for more pronounced myocardial edema and increased need for intraoperative transfusion with HTK.

[Comparative analysis of in-hospital and long-term results of patients with acute dysfunction of coronary bypass grafts depending on treatment tactics]

OBJECTIVE

Comparative analysis of in-hospital and long-term mortality of patients in whom acute dysfunction of coronary bypass grafts was detected in the early postoperative period depending on conservative or surgical tactics.

MATERIAL AND METHODS

The study is a retrospective analysis of data from 8801 patients who underwent elective coronary artery bypass grafting (CABG) between 2011 and 2022 at the Federal Center for Cardiovascular Surgery (Russia, Chelyabinsk). Among them, 196 patients underwent emergency coronary artery bypass grafting due to suspected perioperative myocardial infarction in the early postoperative period. In 119 patients, dysfunction of coronary bypass grafts was detected, in 77 patients no pathological changes were found. The criteria for inclusion in the study were patients with dysfunction of coronary bypass grafts (n=119). The 1st group included patients who underwent conservative therapy (n=33), the 2nd group (n=86) included those who underwent repeated myocardial revascularization. The primary endpoint was hospital mortality, secondary endpoints were long-term mortality and adverse cardiovascular events (myocardial infarction, stroke, repeat myocardial revascularization). Patients were surveyed via telephone.

RESULTS

In-hospital mortality in the group of surgical reintervention was 8.1%, in the group of conservative treatment - 9.1% (p=0.867). According to the results of multivariate analysis, predictors of hospital mortality in patients of both groups were extracorporeal membrane oxygenation (p=0.014), time of artificial circulation (p=0.031), duration of artificial ventilation (p=0.001), number of days in intensive care (p<0.001). When analyzing long-term mortality using the Kaplan-Meier method in group 1 and group 2, no statistically significant differences were found; in the group of conservative therapy - 85±9.6 [66.2-103.7] months versus 108.2±4.8 [98.8-117.6] months in the surgery group (log-rank p=0.06). When analyzing long-term mortality from cardiovascular causes and the occurrence of adverse cardiovascular events, statistically significant differences were determined: in the group of conservative therapy - 92.5±9.3 [74.2-110.7] months versus 117.8±3.3 [111.2-124.3] months in the surgical treatment group (log-rank p=0.007) and 78.1±9.2 [60-96.3] months versus 98.9±3.9 [91.3-106.5] months (log-rank p=0.008), respectively.

CONCLUSION

In-hospital mortality was comparable between groups. Long-term mortality from cardiovascular causes and the number of adverse cardiovascular events were significantly higher in the conservative therapy group. With timely detection of acute dysfunction of coronary bypass grafts, an active surgical approach has an advantage over conservative tactics and can improve the long-term prognosis of patients.

Albumin and Cardioprotection in On-Pump Cardiac Surgery-A Post Hoc Analysis of a Randomized Trial

OBJECTIVES

To study the quantitative potency of plasma albumin on cardioprotection in terms of creatinine kinase-myocardial band mass (CK-MBm) in on-pump cardiac surgery.

DESIGN

Post hoc analysis of a double-blinded randomized clinical trial.

SETTING

Single-center study in the Helsinki University Hospital.

PARTICIPANTS

A total of 1,386 adult on-pump cardiac surgical patients.

INTERVENTION

Administration of 4% albumin (n = 693) or Ringers acetate (n = 693) for cardiopulmonary bypass priming and volume replacement intraoperatively and postoperatively during the first 24 hours.

MEASUREMENTS AND MAIN RESULTS

Albumin concentration was measured preoperatively and intraoperatively (after protamine administration), and CK-MBm on the first postoperative morning. Multivariate linear regression analyses were measured in the whole cohort and the Ringer group. Plasma albumin concentration did not differ between the groups preoperatively (Ringer v albumin: 38.3 ± 5.0 g/L v 38.6 ± 4.5 g/L; p = 0.171) but differed intraoperatively (29.5 ± 5.2 g/L v 41.5 ± 6.0 g/L; p < 0.001). Creatinine kinase-myocardial band mass was higher in the Ringer (32.0 ± 34.8 μg/L) than in the albumin group (24.3 ± 33.0 μg/L) (p < 0.001). Aortic cross-clamping time associated with CK-MBm in the whole cohort (standardized β = 0.376 [95% CI 0.315-0.437], p < 0.001) and the Ringer group (β = 0.363 [0.273-0.452]; p < 0.001). Albumin administration in the whole cohort (β = -0.156 [-0.201 to -0.111]; p < 0.001) and high intraoperative albumin concentration in the Ringer group (β = -0.07 [-0.140 to -0.003]; p = 0.04) associated with reduced CK-MBm. Compared with ischemia-induced increase in CK-MBm, albumin's potency to reduce CK-MBm was 41% in the whole cohort (β-value ratio of -0.156/0.376) and 19% in the Ringer group (β-value ratio of -0.07/0.363).

CONCLUSION

Both endogenous and exogenous albumin appear to be cardioprotective regarding CK-MBm release in on-pump cardiac surgery.

Association of High-Sensitivity Cardiac Troponin T With 30-Day and 5-Year Mortality After Cardiac Surgery

BACKGROUND

The relevance of perioperative myocardial injury (PMI) after cardiac surgery for 30-day mortality and long-term survival remains to be determined.

OBJECTIVES

This study assessed the association of PMI after cardiac surgery, reflected by postoperative troponin release, with 30-day mortality and long-term survival after: 1) coronary artery bypass grafting (CABG); 2) isolated aortic valve replacement (AVR) surgery; and 3) all other cardiac surgeries.

METHODS

A consecutive cohort of 8,292 patients undergoing cardiac surgery with serial perioperative high-sensitivity cardiac troponin T (hs-cTnT) measurements was retrospectively analyzed. The relationship between postoperative hs-cTnT release and 30-day mortality or 5-year mortality was analyzed after adjustment with EuroSCORE II using a Cox proportional hazards model. hs-cTnT thresholds for 30-day and 5-year mortality were determined for isolated CABG (32.3%), AVR (14%), and other cardiac surgery (53.8%).

RESULTS

High postoperative hs-cTnT levels were associated with higher 30-day mortality but not 5-year mortality. In CABG, median peak concentration of postoperative hs-cTnT was 1,044 ng/L, in AVR it was 502 ng/L, and in other cardiac surgery it was 1,110 ng/L. hs-cTnT thresholds defining mortality-associated PMI were as follows: for CABG, 2,385 ng/L (170× the upper reference limit of normal in a seemingly healthy population [URL]); for AVR, 568 ng/L (41× URL); and for other cardiac procedures, 1,873 ng/L (134× URL). hs-cTnT levels above the cutoffs resulted in an HR for 30-day mortality for CABG of 12.56 (P < 0.001), for AVR of 4.44 (P = 0.004), and for other cardiac surgery of 3.97 (P < 0.001).

CONCLUSIONS

PMI reflected by perioperative hs-cTnT release is associated with the expected 30-day mortality but not 5-year mortality. Postoperative hs-cTnT cutoffs to identify survival-relevant PMI are higher than suggested in current definitions.

Vitamin C may reduce troponin and CKMB levels after PCI and CABG: a meta-analysis

BACKGROUND

Ischemia/reperfusion injury contributes to periprocedural myocardial injury (PMI) in patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). PMI can be estimated by the elevation of troponin (Tn) and creatine kinase-MB (CKMB) plasma levels, and it is associated with increased risk of cardiovascular events and mortality. Vitamin C might have a beneficial effect on PMI by improving endothelial function, improving myocardial perfusion, and by reducing oxidative stress generated during/after reperfusion. In several small animal models of cardiac stress, vitamin C reduced the increase in Tn and CKMB levels. The aim of this meta-analysis was to investigate whether vitamin C administration may have an effect on Tn and CKMB levels in patients undergoing PCI or CABG.

METHODS

We searched PubMed, Cochrane, Embase and Scopus databases for controlled clinical trials reporting on Tn and CKMB levels in adult patients who underwent PCI or CABG and received vitamin C. As secondary outcomes we collected data on biomarkers of oxidative stress in the included trials. In our meta-analysis, we used the relative scale and estimated the effect as the ratio of means.

RESULTS

We found seven controlled trials which included 872 patients. All included trials administered vitamin C intravenously, with a range from 1 to 16 g/day, and all initiated vitamin administration prior to the procedure. Vitamin C decreased peak Tn plasma levels in four trials on average by 43% (95% CI: 13 to 63%, p = 0.01) and peak CKMB plasma levels in five trials by 14% (95% CI: 8 to 21%, p < 0.001). Vitamin C also significantly decreased the biomarkers of oxidative stress.

CONCLUSIONS

Vitamin C may decrease cardiac enzyme levels in patients undergoing elective PCI or CABG. This may be explained partially by its antioxidant effects. Our findings encourage further research on vitamin C administration during cardiac procedures and in other clinical contexts that increase the level of cardiac enzymes. Future studies should search for an optimal dosing regimen, taking baseline and follow-up plasma vitamin C levels into account.

Dexmedetomidine Pretreatment Protects Against Myocardial Ischemia/Reperfusion Injury by Activating STAT3 Signaling

BACKGROUND

Myocardial infarction is a common perioperative complication, and blood flow restoration causes ischemia/reperfusion injury (IRI). Dexmedetomidine (DEX) pretreatment can protect against cardiac IRI, but the mechanism is still insufficiently understood.

METHODS

In vivo, myocardial ischemia/reperfusion (30 minutes/120 minutes) was induced via ligation and then reperfusion of the left anterior descending coronary artery (LAD) in mice. Intravenous infusion of 10 μg/kg DEX was performed 20 minutes before ligation. Moreover, the α2-adrenoreceptor antagonist Yohimbine and STAT3 inhibitor Stattic were applied 30 minutes ahead of DEX infusion. In vitro, hypoxia/reoxygenation (H/R) with DEX pretreatment for 1 hour was performed in isolated neonatal rat cardiomyocytes. In addition, Stattic was applied before DEX pretreatment.

RESULTS

In the mouse cardiac ischemia/reperfusion model, DEX pretreatment lowered the serum creatine kinase-MB isoenzyme (CK-MB) levels (2.47 ± 0.165 vs 1.55 ± 0.183; P < .0001), downregulated the inflammatory response ( P ≤ .0303), decreased 4-hydroxynonenal (4-HNE) production and cell apoptosis ( P = .0074), and promoted the phosphorylation of STAT3 (4.94 ± 0.690 vs 6.68 ± 0.710, P = .0001), which could be blunted by Yohimbine and Stattic. The bioinformatic analysis of differentially expressed mRNAs further confirmed that STAT3 signaling might be involved in the cardioprotection of DEX. Upon H/R treatment in isolated neonatal rat cardiomyocytes, 5 μM DEX pretreatment improved cell viability ( P = .0005), inhibited reactive oxygen species (ROS) production and calcium overload (both P ≤ .0040), decreased cell apoptosis ( P = .0470), and promoted STAT3 phosphorylation at Tyr705 (0.102 ± 0.0224 vs 0.297 ± 0.0937; P < .0001) and Ser727 (0.586 ± 0.177 vs 0.886 ± 0.0546; P = .0157), which could be abolished by Stattic.

CONCLUSIONS

DEX pretreatment protects against myocardial IRI, presumably by promoting STAT3 phosphorylation via the α2-adrenoreceptor in vivo and in vitro.

Considerations on the Management of Acute Postoperative Ischemia After Cardiac Surgery: A Scientific Statement From the American Heart Association

Acute postoperative myocardial ischemia (PMI) after cardiac surgery is an infrequent event that can evolve rapidly and become a potentially life-threatening complication. Multiple factors are associated with acute PMI after cardiac surgery and may vary by the type of surgical procedure performed. Although the criteria defining nonprocedural myocardial ischemia are well established, there are no universally accepted criteria for the diagnosis of acute PMI. In addition, current evidence on the management of acute PMI after cardiac surgery is sparse and generally of low methodological quality. Once acute PMI is suspected, prompt diagnosis and treatment are imperative, and options range from conservative strategies to percutaneous coronary intervention and redo coronary artery bypass grafting. In this document, a multidisciplinary group including experts in cardiac surgery, cardiology, anesthesiology, and postoperative care summarizes the existing evidence on diagnosis and treatment of acute PMI and provides clinical guidance.

High sensitivity troponin-I threshold to predict perioperative myocardial infarction

BACKGROUND

High-sensitivity Troponin I (hs-cTnI) has largely replaced conventional troponin assays in an effort to improve detection of myocardial infarction. However, the mean displacement of hs-cTnI following coronary artery bypass graft (CABG) and the optimal threshold to detect perioperative myocardial infarction (MI) is unclear. Our objective is to describe mean hs-cTnI values at 6-12 h post-CABG and to determine the highest specificity while maintaining 100% sensitivity hs-cTnI cut-off values for diagnosis of perioperative or type-5 MI.

METHODS

Between 2016 and 2018, 374 patients underwent non-emergent, isolated CABG. Pre-operative and 6 h post-operative hs-cTnI values were recorded as well as ECG, echocardiographic and angiographic data.

RESULTS

Of 374 patients, 151 (40.3%) had normal and 224 (59.7%) had elevated preoperative hs-cTnI. Patients with normal preoperative hs-cTnI had a mean 6 h hs-cTnI of 9193 ng/l or 270X the upper normal value. Eleven patients (7.3%) presented with post-operative MI with a mean 6 h hs-cTnI of 50,218 ng/l or 1477X the upper normal value. Patients with elevated preoperative hs-cTnI had a mean 6 h hs-cTnI of 9449 ng/l or 292X the upper normal value. Eleven patients (4.9%) who presented with post-operative MI had a mean 6 h hs-cTnI of 26,823 ng/l or 789X the upper normal value.

CONCLUSIONS

We suggest hs-cTnI threshold of 80-fold in patients with normal pre-operative hs-cTnI and 2.7-fold in patients with elevated pre-operative hs-cTnI. These results have important implications for perioperative care and for surgical trial reporting.

Defining Peri-Operative Myocardial Injury during Cardiac Surgery Using High-Sensitivity Troponin T

OBJECTIVE

Cut-offs for high-sensitivity troponin (hs-Tn) elevations to define prognostically significant peri-operative myocardial injury (PMI) in cardiac surgery is not well-established. We evaluated the associations between peri-operative high-sensitivity troponin T (hs-TnT) elevations and 1-year all-cause mortality in patients undergoing cardiac surgery.

METHODS

The prognostic significance of baseline hs-TnT and various thresholds for post-operative hs-TnT elevation at different time-points on 1-year all-cause mortality following cardiac surgery were assessed after adjusting for baseline hs-TnT and EuroSCORE in a post-hoc analysis of the ERICCA trial.

RESULTS

1206 patients met the inclusion criteria. Baseline elevation in hs-TnT >x1 99th percentile upper reference limit (URL) was significantly associated with 1-year all-cause mortality (adjusted hazard ratio 1.90, 95% confidence interval 1.15-3.13). In the subgroup with normal baseline hs-TnT (n = 517), elevation in hs-TnT at all post-operative time points was associated with higher 1-year mortality, reaching statistical significance for elevations above: ≥100 × URL at 6 h; ≥50 × URL at 12 and 24 h; ≥35 × URL at 48 h; and ≥30 × URL at 72 h post-surgery. Elevation in hs-TnT at 24 h ≥ 50 × URL had the optimal sensitivity and specificity (73% and 75% respectively). When the whole cohort of patients was analysed, including those with abnormal baseline hs-TnT (up to 10 × URL), the same threshold had optimal sensitivity and specificity (66% and 70%).

CONCLUSIONS

Both baseline and post-operative hs-TnT elevations are independently associated with 1-year all-cause mortality in patients undergoing cardiac surgery. The optimal threshold to define a prognostically significant PMI in our study was ≥50 × URL elevation in hs-TnT at 24 h.

Endothelial Function and Hypoxic–Hyperoxic Preconditioning in Coronary Surgery with a Cardiopulmonary Bypass: Randomized Clinical Trial

A hypoxic–hyperoxic preconditioning (HHP) may be associated with cardioprotection by reducing endothelial damage and a beneficial effect on postoperative outcome in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Patients (n = 120) were randomly assigned to an HHP and a control group. A safe, inhaled oxygen fraction for the hypoxic preconditioning phase (10–14% oxygen for 10 min) was determined by measuring the anaerobic threshold. At the hyperoxic phase, a 75–80% oxygen fraction was used for 30 min. The cumulative frequency of postoperative complications was 14 (23.3%) in the HHP vs. 23 (41.1%), p = 0.041. The nitrate decreased after surgery by up to 20% in the HHP group and up to 38% in the control group. Endothelin-1 and nitric oxide metabolites were stable in HHP but remained low for more than 24 h in the control group. The endothelial damage markers appeared to be predictors of postoperative complications. The HHP with individual parameters based on the anaerobic threshold is a safe procedure, and it can reduce the frequency of postoperative complications. The endothelial damage markers appeared to be predictors of postoperative complications.

Tranexamic acid is associated with improved hemostasis in elderly patients undergoing coronary-artery surgeries in a retrospective cohort study

Background

More elderly patients undergo coronary artery bypass surgery (CABG) than younger patients. Whether tranexamic acid (TA) is still effective and safe in elderly patients undergoing CABG surgeries is still unclear.

Methods

In this study, a cohort of 7,224 patients ≥70 years undergoing CABG surgery were included. Patients were categorized into the no TA group, TA group, high-dose group, and low-dose group according whether TA was administered and the dose administered. The primary endpoint was blood loss and blood transfusion after CABG. The secondary endpoints were thromboembolic events and in-hospital death.

Results

The blood loss at 24 and 48 h and the total blood loss after surgery in patients in the TA group were 90, 90, and 190 ml less than those in the no-TA group, respectively (p < 0.0001). The total blood transfusion was reduced 0.38-fold with TA administration compared to that without TA (OR = 0.62, 95% CI 0.56-0.68, p < 0.0001). Blood component transfusion was also reduced. High-dose TA administration reduced the blood loss by 20 ml 24 h after surgery (p = 0.032) but had no relationship with the blood transfusion. TA increased the risk of perioperative myocardial infarction (PMI) by 1.62-fold [p = 0.003, OR = 1.62, 95% CI (1.18-2.22)] but reduced the hospital stay time in patients who were administered TA compared to that of patients who did not receive TA (p = 0.026).

Conclusion

We revealed that elderly patients undergoing CABG surgeries had better hemostasis after TA administration but increased the risk of PMI. High-dose TA was effective and safe compared with low-dose TA administration in elderly patients undergoing CABG surgery.

Cardiac troponin release following coronary artery bypass grafting: mechanisms and clinical implications

The use of biomarkers is undisputed in the diagnosis of primary myocardial infarction (MI), but their value for identifying MI is less well studied in the postoperative phase following coronary artery bypass grafting (CABG). To identify patients with periprocedural MI (PMI), several conflicting definitions of PMI have been proposed, relying either on cardiac troponin (cTn) or the MB isoenzyme of creatine kinase, with or without supporting evidence of ischaemia. However, CABG inherently induces the release of cardiac biomarkers, as reflected by significant cTn concentrations in patients with uncomplicated postoperative courses. Still, the underlying (patho)physiological release mechanisms of cTn are incompletely understood, complicating adequate interpretation of postoperative increases in cTn concentrations. Therefore, the aim of the current review is to present these potential underlying mechanisms of cTn release in general, and following CABG in particular (Graphical Abstract). Based on these mechanisms, dissimilarities in the release of cTnI and cTnT are discussed, with potentially important implications for clinical practice. Consequently, currently proposed cTn biomarker cut-offs by the prevailing definitions of PMI might warrant re-assessment, with differentiation in cut-offs for the separate available assays and surgical strategies. To resolve these issues, future prospective studies are warranted to determine the prognostic influence of biomarker release in general and PMI in particular.

High-Sensitivity Cardiac Troponin I and T Kinetics Differ following Coronary Bypass Surgery: A Systematic Review and Meta-Analysis

Background

Cardiac troponin I and T are both used for diagnosing myocardial infarction (MI) after coronary artery bypass grafting (CABG), also known as type 5 MI (MI-5). Different MI-5 definitions have been formulated, using multiples of the 99th percentile upper reference limit (10×, 35×, or 70× URL), with or without supporting evidence. These definitions are arbitrarily chosen based on conventional assays and do not differentiate between troponin I and T. We therefore investigated the kinetics of high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) following CABG.

Methods

A systematic search was applied to MEDLINE and EMBASE databases including the search terms “coronary artery bypass grafting” AND “high-sensitivity cardiac troponin.” Studies reporting hs-cTnI or hs-cTnT on at least 2 different time points were included. Troponin concentrations were extracted and normalized to the assay-specific URL.

Results

For hs-cTnI and hs-cTnT, 17 (n = 1661 patients) and 15 studies (n = 2646 patients) were included, respectively. Preoperative hs-cTnI was 6.1× URL (95% confidence intervals: 4.9–7.2) and hs-cTnT 1.2× URL (0.9–1.4). Mean peak was reached 6–8 h postoperatively (126× URL, 99–153 and 45× URL, 29–61, respectively). Subanalysis of hs-cTnI illustrated assay-specific peak heights and kinetics, while subanalysis of surgical strategies revealed 3-fold higher hs-cTnI than hs-cTnT for on-pump CABG and 5-fold for off-pump CABG.

Conclusion

Postoperative hs-cTnI and hs-cTnT following CABG surpass most current diagnostic cutoff values. hs-cTnI was almost 3-fold higher than hs-cTnT, and appeared to be highly dependent on the assay used and surgical strategy. There is a need for assay-specific hs-cTnI and hs-cTnT cutoff values for accurate, timely identification of MI-5.

Prognostic value of high-sensitivity cardiac troponin I early after coronary artery bypass graft surgery

BACKGROUND

The diagnosis of periprocedural myocardial infarction (PMI) after coronary artery bypass graft (CABG) is based on biochemical markers along with clinical and instrumental findings. However, there is not a clear cutoff value of high-sensitivity cardiac troponin (hs-cTn) to identify PMI. We hypothesized that isolated hs-cTn concentrations in the first 24 h following CABG could predict cardiac adverse events (in-hospital death and PMI) and/or left ventricular ejection fraction (LVEF) decrease.

METHODS

We retrospectively enrolled all consecutive adult patients undergoing CABG, alone or in association with other cardiac surgery procedures, over 1 year. Hs-cTn I concentrations (Access, Beckman Coulter) were serially measured in the post-operative period and analyzed according to post-operative outcomes.

RESULTS

300 patients were enrolled; 71.3% underwent CABG alone, 33.7% for acute coronary syndrome. Most patients showed hs-cTn I values superior to the limit required by the latest guidelines for the diagnosis of PMI. Five patients (1.7%) died, 8% developed a PMI, 10.6% showed a LVEF decrease ≥ 10%. Hs-cTn I concentrations did not significantly differ with respect to death and/or PMI whereas they were associated with LVEF decrease ≥ 10% (p value < 0.005 at any time interval), in particular hs-cTn I values at 9-12 h post-operatively. A hs-cTn I cutoff of 5556 ng/L, a value 281 (for males) and 479 (for females) times higher than the URL, at 9-12 h post-operatively was identified, representing the best balance between sensitivity (55%) and specificity (79%) in predicting LVEF decrease ≥ 10%.

CONCLUSIONS

Hs-cTn I at 9-12 h post-CABG may be useful to early identify patients at risk for LVEF decrease and to guide early investigation and management of possible post-operative complications.

No Association of Early Postoperative Heart Rate With Outcomes After Coronary Artery Bypass Grafting

BACKGROUND

Elevated perioperative heart rate potentially causes perioperative myocardial injury because of imbalance in oxygen supply and demand. However, large multicenter studies evaluating early postoperative heart rate and major adverse cardiac and cerebrovascular events (MACCEs) are lacking.

OBJECTIVE

To assess the associations of 4 postoperative heart rate assessment methods with in-hospital MACCEs after elective coronary artery bypass grafting (CABG).

METHODS

Using data from the eICU Collaborative Research Database in the United States from 2014 to 2015, the study evaluated postoperative heart rate measured during hospitalization within 24 hours after intensive care unit admission. Four heart rate assessment methods were evaluated: maximum heart rate, duration above heart rate 100/min, area above heart rate 100/min, and time-weighted average heart rate. The outcome was in-hospital MACCEs, defined as a composite of in-hospital death, myocardial infarction, angina, arrhythmia, heart failure, stroke, cardiac arrest, or repeat revascularization.

RESULTS

Among 2585 patients, the crude rate of in-hospital MACCEs was 6.2%. In multivariable logistic regression analysis, the adjusted odds ratios (95% CI) for in-hospital MAC-CEs assessed by maximum heart rate in each heart rate category (beats per minute: >100-110, >110-120, >120-130, and >130) were 1.43 (0.95-2.15), 0.98 (0.56-1.64), 1.47 (0.76-2.69), and 1.71 (0.80-3.35), respectively. Similarly, none of the other 3 methods were associated with MACCEs.

CONCLUSIONS

More research is needed to assess the usefulness of heart rate measurement in patients after CABG.

Myocardial Injury, Troponin Release and Cardiomyocyte Death in Brief Ischemia, Failure and Ventricular Remodeling

Troponin released from irreversibly injured myocytes is the gold standard biomarker for the rapid identification of an acute coronary syndrome. In acute myocardial infarction, necrotic cell death is characterized by sarcolemmal disruption in response to a critical level of energy depletion after more than 15-minutes of ischemia. While troponin I and T are highly specific for cardiomyocyte death, high-sensitivity assays have demonstrated that measurable circulating levels of troponin are present in the majority of normal subjects. In addition, transient as well as chronic elevations have been demonstrated in many disease states not clearly associated with myocardial ischemia. The latter observations have given rise to the clinical concept of myocardial injury. This review will summarize evidence supporting the notion that circulating troponin levels parallel the extent of myocyte apoptosis in normal ventricular remodeling and in pathophysiological conditions not associated with infarction or necrosis. It will review the evidence that myocyte apoptosis can be accelerated by both diastolic strain from elevated ventricular preload as well as systolic strain from dyskinesis after brief episodes of ischemia too short to cause a critical level of myocyte energy depletion. We then show how chronic, low rates of myocyte apoptosis from endogenous myocyte turnover, repetitive ischemia or repetitive elevations in LV diastolic pressure can lead to significant myocyte loss in the absence of neurohormonal stimulation. Finally, we posit that the differential response to strain-induced injury in heart failure may determine whether progressive myocyte loss and HFrEF or interstitial fibrosis and HFpEF become the heart failure phenotype.

Blunting TRPML1 channels protects myocardial ischemia/reperfusion injury by restoring impaired cardiomyocyte autophagy

Accumulating evidence suggests that autophagy dysfunction plays a critical role in myocardial ischemia/reperfusion (I/R) injury. However, the underling mechanism of malfunctional autophagy in the cardiomyocytes subjected to I/R has not been well defined. As a result, there is no effective therapeutic option by targeting autophagy to prevent myocardial I/R injury. Here, we used both an in vitro and an in vivo I/R model to monitor autophagic flux in the cardiomyocytes, by exposing neonatal rat ventricular myocytes to hypoxia/reoxygenation and by subjecting mice to I/R, respectively. We observed that the autophagic flux in the cardiomyocytes subjected to I/R was blocked in both in vitro and in vivo models. Down-regulating a lysosomal cationic channel, TRPML1, markedly restored the blocked myocardial autophagic flux induced by I/R, demonstrating that TRPML1 directly contributes to the blocked autophagic flux in the cardiomyocytes subjected to I/R. Mechanistically, TRPML1 is activated secondary to ROS elevation following ischemia/reperfusion, which in turn induces the release of lysosomal zinc into the cytosol and ultimately blocks the autophagic flux in cardiomyocytes, presumably by disrupting the fusion between autophagosomes and lysosomes. As a result, the inhibited myocardial autophagic flux induced by TRPML1 disrupted mitochondria turnover and resulted in mass accumulation of damaged mitochondria and further ROS release, which directly led to cardiomyocyte death. More importantly, pharmacological and genetic inhibition of TRPML1 channels greatly reduced infarct size and rescued heart function in mice subjected to I/R in vivo by restoring impaired myocardial autophagy. In summary, our study demonstrates that secondary to ROS elevation, activation of TRPML1 results in autophagy inhibition in the cardiomyocytes subjected to I/R, which directly leads to cardiomyocyte death by disrupting mitochondria turnover. Therefore, targeting TRPML1 represents a novel therapeutic strategy to protect against myocardial I/R injury.

Serum FGF21 Levels Predict the MACE in Patients With Myocardial Infarction After Coronary Artery Bypass Graft Surgery

Objectives

Prognosis evaluation in myocardial infarction (MI) patients with major adverse clinical events (MACE) who have undergone coronary artery bypass graft (CABG) is greatly important to identify high-risk patients. Elevated metabolic hormone fibroblast growth factor 21 (FGF21) is associated with the risk of MI. The aim of this study is to assess the relationship between FGF21 and the incidence of MACE in patients with MI after CABG surgery.

Methods

Patients with three-vessel disease who were scheduled for first-time isolated CABG were enrolled in this project and underwent to evaluate the incidence of MACE during 48 h after CABG surgery, as well as to collect serum samples for FGF21 levels in both preoperative- and postoperative-CABG (pre-CABG and post-CABG).

Results

A total of 265 patients with MI undergoing CABG were enrolled in this study, 21 patients experienced MACE during the 48 h after CAGB surgery. Serum FGF21 levels of patients with MACE at post-CABG were significantly higher than that in patients without MACE [553.7 (433.6) vs. 291.7 (334.4), p &lt; 0.001]. Furthermore, among 81 individuals of these 265 patients, a lower level of FGF21 in preoperative-CABG (pre-CABG) and a higher level of FGF21 at postoperative-CABG (post-CABG) were observed in MI patients with MACE as compared to those without MACE respectively [ (275.0 (260.4) vs. 410.3 (420.7), p = 0.049; 550.7 (519.9) vs. 370.6 (441.2), p = 0.031]. In addition, serum FGF21 levels of MI patients with MACE at post-CABG were significantly increased compared with the baseline levels in pre-CABG [550.7 (519.9) vs.275.0 (260.4) p &lt; 0.001]. However, these profiles were not observed in patients without MACE [410.3 (420.7) vs. 370.6 (441.2), p=0.2137]. Logistic regression analysis demonstrated that both serum FGF21 and CK-MB levels at post-CABG were independently associated with the incidence of MACE in patients with MI after CABG surgery. Finally, ROC analysis for FGF21 levels of 265 MI patients at post-CABG identified 455.4 pg/ml as an optimal cut-off value to predict MACE, with a sensitivity and specificity of 91.7 and 68.4% respectively.

Conclusion

Serum FGF21 levels at post-CABG are independently associated with the incidence of MACE in patients with MI who have undergone CABG. Measurement of FGF21 may help distinguish patients with MI at a high risk of MACE after CABG surgery.

Contemporary coronary artery bypass graft surgery and subsequent percutaneous revascularization

Patients who have undergone coronary artery bypass graft (CABG) surgery are susceptible to bypass graft failure and progression of native coronary artery disease. Although the saphenous vein graft (SVG) was traditionally the most-used conduit, arterial grafts (including the left and right internal thoracic arteries and the radial artery) have improved patency rates. However, the need for secondary revascularization remains common, and percutaneous coronary intervention (PCI) has become the most common modality of secondary revascularization after CABG surgery. Procedural characteristics and clinical outcomes differ considerably from those associated with PCI in patients without previous CABG surgery, owing to altered coronary anatomy and differences in conduit pathophysiology. In particular, SVG PCI carries an increased risk of complications, and operators are shifting their focus towards embolic protection strategies and complex native-vessel interventions, increasingly using SVGs as conduits to facilitate native-vessel PCI rather than pursuing SVG PCI. In this Review, we discuss the differences in conduit pathophysiology, changes in CABG surgery techniques, and the latest evidence in terms of PCI in patients with previous CABG surgery, with a particular emphasis on safety and long-term efficacy. We explore the subject of contemporary CABG surgery and subsequent percutaneous revascularization in this complex patient population.

High-sensitivity cardiac troponin I after coronary artery bypass grafting for post-operative decision-making

AIMS

Current troponin cut-offs suggested for the post-operative workup of patients following coronary artery bypass graft (CABG) surgery are based on studies using non-high-sensitive troponin assays or are arbitrarily chosen. We aimed to identify an optimal cut-off and timing for a proprietary high-sensitivity cardiac troponin I (hs-cTnI) assay to facilitate post-operative clinical decision-making.

METHODS AND RESULTS

We performed a retrospective analysis of all patients undergoing elective isolated CABG at our centre between January 2013 and May 2019. Of 4684 consecutive patients, 161 patients (3.48%) underwent invasive coronary angiography after surgery, of whom 86 patients (53.4%) underwent repeat revascularization. We found an optimal cut-off value for peak hs-cTnI of >13 000 ng/L [>500× the upper reference limit (URL)] to be significantly associated with repeat revascularization within 48 h after surgery, which was internally validated through random repeated sampling with 1000 iterations. The same cut-off also predicted 30-day major adverse cardiovascular events and all-cause mortality after a median follow-up of 3.1 years, which was validated in an external cohort. A decision tree analysis of serial hs-cTnI measurements showed no added benefit of hs-cTnI measurements in patients with electrocardiographic or echocardiographic abnormalities or haemodynamic instability. Likewise, early post-operative hs-cTnI elevations had a low yield for clinical decision-making and only later elevations (at 12-16 h post-operatively) using a threshold of 8000 ng/L (307× URL) were significantly associated with repeat revascularization with an area under the curve of 0.92 (95% confidence interval 0.88-0.95).

CONCLUSION

Our data suggest that for hs-cTnI, higher cut-offs than currently recommended should be used in the post-operative management of patients following CABG.

Tranexamic Acid Administered During Off-Pump Coronary Artery Bypass Graft Surgeries Achieves Good Safety Effects and Hemostasis

BACKGROUND

Tranexamic acid (TXA) administered during off-pump coronary artery bypass (OPCAB) surgeries has achieved good blood control in small cohorts. We aimed to investigate the safety issues and hemostasis associated with TXA administration during OPCAB in a large retrospective cohort study.

METHODS

This study included 19,687 patients with OPCAB from 2009 to 2019. A total of 1,307 patients were excluded because they were younger than 18 years or certain values were missing. Among the remaining 18,380 patients, 10,969 were in the TXA group and 7,411 patients were in the no-TXA group. There were 4,889 patients whose TXA dose was ≥50 mg/kg, and the remaining 6,080 patients had a TXA dose of <50 mg/kg. Propensity score matching (PSM) was performed between the TXA and no-TXA groups and between the high-dose and low-dose groups, and statistical analysis was performed.

RESULTS

Tranexamic acid administration did not increase the risk of hospital death or thromboembolic events. Patients who administered TXA had less blood loss at 24 h (478.32 ± 276.41 vs. 641.28 ± 295.09, p < 0.001) and 48 h (730.59 ± 358.55 vs. 915.24 ± 390.13, p < 0.001) and total blood loss (989.00 ± 680.43 vs. 1,220.01 ± 720.68, p < 0.001) after OPCAB than the patients with non-TXA. Therefore, the risk of total blood exposure [odds ratio (OR) = 0.50, 95% CI 0.47-0.54, p < 0.001] or blood component exposure (p < 0.001) was decreased significantly in the patients who administered TXA. The TXA dosage did not impact the patient survival, thromboembolic events, or blood management.

CONCLUSIONS

The application of TXA was safe and provided blood control in patients with OPCAB, and the dosage did not affect these parameters.

Meta-Analysis Evaluating High-Sensitivity Cardiac Troponin T Kinetics after Coronary Artery Bypass Grafting in Relation to the Current Definitions of Myocardial Infarction

Various definitions of myocardial infarction type 5 after coronary artery bypass grafting (CABG) have been proposed (myocardial infarction [MI-5], also known as peri-procedural MI), using different biomarkers and different and arbitrary cut-off values. This meta-analysis aims to determine the expected release of high-sensitivity cardiac troponin T (hs-cTnT) after CABG in general and after uncomplicated surgery and off-pump CABG in particular. A systematic search was applied to 3 databases. Studies on CABG as a single intervention and reporting on postoperative hs-cTnT concentrations on at least 2 different time points were included. All data on hs-cTnT concentrations were extracted, and mean concentrations at various points in time were stratified. Eventually, 15 studies were included, encompassing 2,646 patients. Preoperative hs-cTnT was 17 ng/L (95% confidence interval [CI] 13 to 20 ng/L). Hs-cTnT peaked at 6 to 8 hours postoperatively (628 ng/L, 95% CI 400 to 856 ng/L; 45x upper reference limit [URL]) and was still increased after 48 hours. In addition, peak hs-cTnT concentration was 614 ng/L (95% CI 282 to 947 ng/L) in patients with a definite uncomplicated postoperative course (i.e., without MI). For patients after off-pump CABG compared to on-pump CABG, the mean peak hs-cTnT concentration was 186 ng/L (95% CI 172 to 200 ng/L, 13 × URL) versus 629 ng/L (95% CI 529 to 726 ng/L, 45 × URL), respectively. In conclusion, postoperative hs-cTnT concentrations surpass most of the currently defined cut-off values for MI-5, even in perceived uncomplicated surgery, suggesting thorough reassessment. Hs-cTnT release differences following on-pump CABG versus off-pump CABG were observed, implying the need for different cut-off values for different surgical strategies.

Non-invasive Ischaemia Testing in Patients With Prior Coronary Artery Bypass Graft Surgery: Technical Challenges, Limitations, and Future Directions

Coronary artery bypass graft (CABG) surgery effectively relieves symptoms and improves outcomes. However, patients undergoing CABG surgery typically have advanced coronary atherosclerotic disease and remain at high risk for symptom recurrence and adverse events. Functional non-invasive testing for ischaemia is commonly used as a gatekeeper for invasive coronary and graft angiography, and for guiding subsequent revascularisation decisions. However, performing and interpreting non-invasive ischaemia testing in patients post CABG is challenging, irrespective of the imaging modality used. Multiple factors including advanced multi-vessel native vessel disease, variability in coronary hemodynamics post-surgery, differences in graft lengths and vasomotor properties, and complex myocardial scar morphology are only some of the pathophysiological mechanisms that complicate ischaemia evaluation in this patient population. Systematic assessment of the impact of these challenges in relation to each imaging modality may help optimize diagnostic test selection by incorporating clinical information and individual patient characteristics. At the same time, recent technological advances in cardiac imaging including improvements in image quality, wider availability of quantitative techniques for measuring myocardial blood flow and the introduction of artificial intelligence-based approaches for image analysis offer the opportunity to re-evaluate the value of ischaemia testing, providing new insights into the pathophysiological processes that determine outcomes in this patient population.