Intraoperative Anemia Mediates Sex Disparity in Operative Mortality After Coronary Artery Bypass Grafting.

BACKGROUND: Women undergoing coronary artery bypass grafting (CABG) have higher operative mortality than men. OBJECTIVES: The purpose of this study was to evaluate the relationship between intraoperative anemia (nadir intraoperative hematocrit), CABG operative mortality, and sex. METHODS: This was a cohort study of 1,434,225 isolated primary CABG patients (344,357 women) from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (2011-2022). The primary outcome was operative mortality. The attributable risk (AR) (the risk-adjusted strength of the association of female sex with CABG outcomes) for the primary outcome was calculated. Causal mediation analysis derived the total effect of female sex on operative mortality risk and the proportion of that effect mediated by intraoperative anemia. RESULTS: Women had lower median nadir intraoperative hematocrit (22.0% [Q1-Q3: 20.0%-25.0%] vs 27.0% [Q1-Q3: 24.0%-30.0%], standardized mean difference 97.0%) than men. Women had higher operative mortality than men (2.8% vs 1.7%; P < 0.001; adjusted OR: 1.36; 95% CI: 1.30-1.41). The AR of female sex for operative mortality was 1.21 (95% CI: 1.17-1.24). After adjusting for nadir intraoperative hematocrit, AR was reduced by 43% (1.12; 95% CI: 1.09-1.16). Intraoperative anemia mediated 38.5% of the increased mortality risk associated with female sex (95% CI: 32.3%-44.7%). Spline regression showed a stronger association between operative mortality and nadir intraoperative hematocrit at hematocrit values <22.0% (P < 0.001). CONCLUSIONS: The association of female sex with increased CABG operative mortality is mediated to a large extent by intraoperative anemia. Avoiding nadir intraoperative hematocrit values below 22.0% may reduce sex differences in CABG operative mortality.

External Stenting for Saphenous Vein Grafts in Coronary Surgery: A Systematic Review and Meta-Analysis.

The external stenting of saphenous vein grafts (SVGs) during coronary artery bypass grafting (CABG) has been proven to reduce intimal hyperplasia (IH) in animal models, paving the way for human randomized controlled trials (RCTs) to be conducted. Herein, we performed a study-level meta-analysis to assess the impact of the Venous External SupporT (VEST) device, an external stent, on the outcomes of SVGs. A systematic search was conducted to identify all RCTs comparing VEST-stented to non-stented SVGs in patients undergoing CABG. The primary outcome was graft occlusion. The main secondary outcomes were repeat revascularization, SVG IH area, and intimal-medial thickness. Two RCTs totaling 407 patients were included. At a mean follow-up of 1.5 years, there was no difference in graft occlusion between groups (incidence rate ratio: 1.11; 95% confidence interval (CI): 0.80-1.53). The rate of repeat revascularization was also similar (odds ratio: 0.66; 95% CI: 0.27-1.64). The IH area (standardized mean difference (SMD): -0.45; 95% CI: -0.79 to -0.10) and intimal-medial thickness (SMD: -0.50; 95% CI: -0.90 to -0.10) were significantly reduced in the VEST group. Our findings show that significant reductions in the IH area and the intimal-medial thickness in VEST-stented SVGs do not currently translate into a lesser need for repeat revascularization or less graft occlusion events compared to non-stented SVGs at 1.5 years after CABG.

The Effect of Posterior Pericardiotomy on the Incidence of Atrial Fibrillation After Cardiac Surgery-Extended Follow-Up study (PALACS-EF): rationale and design.

Aims: Postoperative atrial fibrillation (POAF) is the most common complication of cardiac surgery and has been associated with increased postoperative morbidity and hospital costs. The Posterior left pericardiotomy for the prevention of AtriaL fibrillation After Cardiac Surgery (PALACS) trial found that posterior pericardiotomy significantly reduced the incidence of POAF (17% vs. 32%, P < 0.001). We present the protocol for The Effect of Posterior Pericardiotomy on the Incidence of Atrial Fibrillation After Cardiac Surgery-Extended Follow-Up study (PALACS-EF): a prospective, extended follow-up of the original PALACS trial. The aim of PALACS-EF is to gain more data regarding the effect of posterior pericardiotomy on postdischarge clinical outcomes. The primary outcome is the time to the first occurrence of the composite of all-cause mortality or hospital cardiovascular readmission. The key secondary outcome is the time to the first occurrence of the composite of all-cause mortality and all-cause hospital readmission. Hospital readmission, myocardial infarction, stroke, transient ischaemic attack, heart failure, systemic embolism, or new arrhythmias with onset since 30-day follow-up will also be recorded. Methods and results: All 420 patients enrolled in the PALACS trial will be included; extended follow-up will be conducted via telephone by blinded research personnel utilizing a standardized script to ensure uniformity and completeness of follow-up. If an event has occurred, documentation will be obtained, and an independent adjudication committee blinded to group assignment will adjudicate outcome events. Results will be reported when a median follow-up of 5 years is achieved. Conclusion: PALACS-EF will provide data to answer the question of whether posterior pericardiotomy improves postdischarge outcomes in patients undergoing cardiac surgery, and it will provide information on the relationship between POAF and adverse postdischarge outcomes including mortality, hospitalization, heart failure, and stroke. Registration: PALACS: NCT02875405, PALACS-EF: NCT05903222.

The VEST External Support for Saphenous Vein Grafts in Coronary Surgery: A Review of Randomized Clinical Trials.

Saphenous vein grafts (SVGs) are the most frequently used conduits in coronary artery bypass grafting (CABG), but their higher rate of occlusion compared to arterial conduits remains a concern. Previous studies have shown that SVG failure is mainly driven by intimal hyperplasia, an adaptative response to higher pressures of the arterial circulation. The VESTTM device (Vascular Graft Solutions, Tel Aviv, Israel), an external support designed to mitigate intimal hyperplasia in SVGs, has been tested in few clinical trials (RCTs). Herein, we descriptively evaluated the randomized evidence on the VEST device.

Sex differences in coronary artery bypass graft surgery outcomes: a narrative review.

Background and Objective: Coronary artery bypass grafting (CABG) is the most commonly performed cardiac surgery globally and in the United States, however, women have worse outcomes than men. We aim to examine the possible drivers of this sex difference in CABG outcomes. Methods: A narrative review using a current search of the most recent literature on this topic. Key Content and Findings: The sex difference in outcomes after CABG has persisted despite advances in the field, with women having well-described worse operative mortality and morbidity than men. Several explanatory mechanisms have been proposed for these differences. These include, but are not limited to, preoperative factors such as the natural history of coronary artery disease in women, older age, and higher prevalence of comorbidities at the time of presentation for CABG surgery. Intraoperative factors have also been proposed to play a role, including the smaller coronary artery size and greater coronary artery reactivity in women, the degree of intraoperative hemodilution anemia, the type of grafting, and the completeness of revascularization. However, no definitive etiology has been identified to date. Conclusions: The sex difference in outcomes after CABG remains present, and despite numerous proposed etiopathologies, the main driver remains unclear. Further research is needed to identify, and address, the root cause of this difference, and greater participation of women in cardiovascular and cardiac surgery trials is crucial.

Differences in Postoperative Atrial Fibrillation Incidence and Outcomes After Cardiac Surgery According to Assessment Method and Definition: A Systematic Review and Meta-Analysis.

BACKGROUND: Postoperative atrial fibrillation (POAF) is the most frequent complication of cardiac surgery. Despite clinical and economic implications, ample variability in POAF assessment method and definition exist across studies. We performed a study-level meta-analysis to evaluate the influence of POAF assessment method and definition on its incidence and association with clinical outcomes. METHODS AND RESULTS: A systematic literature search was conducted to identify studies comparing the outcomes of patients with and without POAF after cardiac surgery that also reported POAF assessment method. The primary outcome was POAF incidence. The secondary outcomes were in-hospital mortality, stroke, intensive care unit length of stay, and postoperative length of stay. Fifty-nine studies totaling 197 774 patients were included. POAF cumulative incidence was 26% (range: 7.3%-53.1%). There were no differences in POAF incidence among assessment methods (27%, [range: 7.3%-53.1%] for continuous telemetry, 27% [range: 7.9%-50%] for telemetry plus daily ECG, and 19% [range: 7.8%-42.4%] for daily ECG only; P>0.05 for all comparisons). No differences in in-hospital mortality, stroke, intensive care unit length of stay, and postoperative length of stay were found between assessment methods. No differences in POAF incidence or any other outcomes were found between POAF definitions. Continuous telemetry and telemetry plus daily ECG were associated with higher POAF incidence compared with daily ECG in studies including only patients undergoing isolated coronary artery bypass grafting. CONCLUSIONS: POAF incidence after cardiac surgery remains high, and detection rates are variable among studies. POAF incidence and its association with adverse outcomes are not influenced by the assessment method and definition used, except in patients undergoing isolated coronary artery bypass grafting.

Graft Failure After Coronary Artery Bypass Grafting and Its Association With Patient Characteristics and Clinical Events: A Pooled Individual Patient Data Analysis of Clinical Trials With Imaging Follow-Up.

BACKGROUND: Graft patency is the postulated mechanism for the benefits of coronary artery bypass grafting (CABG). However, systematic graft imaging assessment after CABG is rare, and there is a lack of contemporary data on the factors associated with graft failure and on the association between graft failure and clinical events after CABG. METHODS: We pooled individual patient data from randomized clinical trials with systematic CABG graft imaging to assess the incidence of graft failure and its association with clinical risk factors. The primary outcome was the composite of myocardial infarction or repeat revascularization occurring after CABG and before imaging. A 2-stage meta-analytic approach was used to evaluate the association between graft failure and the primary outcome. We also assessed the association between graft failure and myocardial infarction, repeat revascularization, or all-cause death occurring after imaging. RESULTS: Seven trials were included comprising 4413 patients (mean age, 64.4±9.1 years; 777 [17.6%] women; 3636 [82.4%] men) and 13 163 grafts (8740 saphenous vein grafts and 4423 arterial grafts). The median time to imaging was 1.02 years (interquartile range [IQR], 1.00-1.03). Graft failure occurred in 1487 (33.7%) patients and in 2190 (16.6%) grafts. Age (adjusted odds ratio [aOR], 1.08 [per 10-year increment] [95% CI, 1.01-1.15]; P=0.03), female sex (aOR, 1.27 [95% CI, 1.08-1.50]; P=0.004), and smoking (aOR, 1.20 [95% CI, 1.04-1.38]; P=0.01) were independently associated with graft failure, whereas statins were associated with a protective effect (aOR, 0.74 [95% CI, 0.63-0.88]; P<0.001). Graft failure was associated with an increased risk of myocardial infarction or repeat revascularization occurring between CABG and imaging assessment (8.0% in patients with graft failure versus 1.7% in patients without graft failure; aOR, 3.98 [95% CI, 3.54-4.47]; P<0.001). Graft failure was also associated with an increased risk of myocardial infarction or repeat revascularization occurring after imaging (7.8% versus 2.0%; aOR, 2.59 [95% CI, 1.86-3.62]; P<0.001). All-cause death after imaging occurred more frequently in patients with graft failure compared with patients without graft failure (11.0% versus 2.1%; aOR, 2.79 [95% CI, 2.01-3.89]; P<0.001). CONCLUSIONS: In contemporary practice, graft failure remains common among patients undergoing CABG and is strongly associated with adverse cardiac events.

Operative Outcomes of Women Undergoing Coronary Artery Bypass Surgery in the US, 2011 to 2020.

Importance: It has been reported that women undergoing coronary artery bypass have higher mortality and morbidity compared with men but it is unclear if the difference has decreased over the last decade. Objective: To evaluate trends in outcomes of women undergoing coronary artery bypass in the US from 2011 to 2020. Design, Setting, and Participants: This retrospective cohort study at hospitals contributing to the Adult Cardiac Surgery Database of the Society of Thoracic Surgeons included 1 297 204 patients who underwent primary isolated coronary artery bypass from 2011 to 2020. Exposure: Coronary artery bypass. Main Outcomes and Measures: The primary outcome was operative mortality. The secondary outcome was the composite of operative mortality and morbidity (including operative mortality, stroke, kidney failure, reoperation, deep sternal wound infection, prolonged mechanical ventilation, and prolonged hospital stay). The attributable risk (the association of female sex with coronary artery bypass grafting outcomes) for the primary and secondary outcomes was calculated. Results: Between 2011 and 2020, 1 297 204 patients underwent primary isolated coronary artery bypass grafting with a mean age of 66.0 years, 317 716 of which were women (24.5%). Women had a higher unadjusted operative mortality (2.8%; 95% CI, 2.8-2.9 vs 1.7%; 95% CI, 1.7-1.7; P < .001) and overall unadjusted incidence of the composite of operative mortality and morbidity compared with men (22.9%; 95% CI, 22.7-23.0 vs 16.7%; 95% CI, 16.6-16.8; P < .001). The attributable risk of female sex for operative mortality varied from 1.28 in 2011 to 1.41 in 2020, with no significant change over the study period (P for trend = 0.38). The attributable risk for the composite of operative mortality and morbidity was 1.08 in both 2011 and 2020 with no significant change over the study period (P for trend = 0.71). Conclusions and Relevance: Women remain at significantly higher risk for adverse outcomes following coronary artery bypass grafting and no significant improvement has been seen over the course of the last decade. Further investigation into the determinants of operative outcomes in women is urgently needed.

Graft thrombosis after coronary artery bypass surgery and current practice for prevention.

Coronary artery bypass grafting (CABG) is the most frequently performed cardiac surgery worldwide. The reported incidence of graft failure ranges between 10% and 50%, depending upon the type of conduit used. Thrombosis is the predominant mechanism of early graft failure, occurring in both arterial and vein grafts. Significant advances have been made in the field of antithrombotic therapy since the introduction of aspirin, which is regarded as the cornerstone of antithrombotic therapy for prevention of graft thrombosis. Convincing evidence now exists that dual antiplatelet therapy (DAPT), consisting of aspirin and a potent oral P2Y12 inhibitor, effectively reduces the incidence of graft failure. However, this is achieved at the expense of an increase in clinically important bleeding, underscoring the importance of balancing thrombotic risk and bleeding risk when considering antithrombotic therapy after CABG. In contrast, anticoagulant therapy has proved ineffective at reducing the occurrence of graft thrombosis, pointing to platelet aggregation as the key driver of graft thrombosis. We provide a comprehensive review of current practice for prevention of graft thrombosis and discuss potential future concepts for antithrombotic therapy including P2Y12 inhibitor monotherapy and short-term DAPT.

Angiographic Outcomes for Arterial and Venous Conduits Used in CABG.

Coronary artery bypass grafting is the most commonly performed cardiac surgical procedure. Conduit selection is crucial to achieving early optimal outcomes, with graft patency being likely the main driver to long-term survival. We present a review of current evidence on the patency of arterial and venous bypass conduits and of differences in angiographic outcomes.

Gender Disparities in Cardiac Surgery Trials: Leadership, Authorship, and Patient Enrollment.

BACKGROUND: Studies have highlighted the paucity of women-led randomized controlled trials (RCTs) in cardiovascular medicine. Whether this finding also applies to cardiac surgery has not been evaluated. In this study, we evaluate women authorship, leadership, and women enrollment in cardiac surgery RCTs. METHODS: A systematic literature search was conducted to identify RCTs comparing 2 or more adult cardiac surgical procedures published from 2000 to 2022. Women-led RCTs were defined as those with a woman as either a first or last author. Linear regression and correlation analyses were used. RESULTS: Of 58 RCTs, 8 (13.8%) were women-led; 17 (29.3%) RCTs had no women authors. Overall, 17.9% of all authors were women, but only 1.2% of all authors were women cardiac surgeons and only 19% of the RCTs had a women cardiac surgeon among the authors. The median proportion of women authors was 14.3% by RCT, which was significantly higher in women-led compared with men-led RCTs (28.6% vs 11.8%; P = .01). No significant change in the proportion of women authors was observed during the study period. North American RCTs had a higher proportion of women authors compared with other geographic regions (28.6% vs 12.5%; P = .01). No correlation was found between the proportion of women authors and the proportion of women participants enrolled in individual RCTs. CONCLUSIONS: During the last 2 decades, only a minority of cardiac surgery RCTs were women-led, and no significant increase in women authorship occurred. There are important geographic differences in women authorship.

Characteristics of Postoperative Atrial Fibrillation and the Effect of Posterior Pericardiotomy.

BACKGROUND: Postoperative atrial fibrillation (POAF) is a frequent complication of cardiac surgery. However, only a few detailed descriptions of the arrhythmia have been reported. We aim to describe the characteristics, outcomes, and variables associated with POAF and to evaluate how posterior pericardiotomy (PP) affects POAF characteristics. METHODS: In this post hoc analysis of the Posterior left pericardiotomy for the prevention of AtriaL fibrillation After Cardiac Surgery (PALACS) trial, we describe POAF characteristics based on continuous in-hospital telemetry data. RESULTS: Of 420 patients, 103 (24.5%) developed POAF. Median time to onset was 50.3 hours; 70.9% of events occurred within 3 days. Hemodynamic instability and rapid ventricular response occurred in 8.7% and 51.5% of cases, respectively. Most POAF patients received antiarrhythmics (97.1%), 22.3% electrical cardioversion, and 40.8% systemic anticoagulation. Median POAF duration was 24.0 hours; 70.9% of cases resolved within 36 hours. Median POAF burden was 15.9%. All patients were in sinus rhythm at follow-up. POAF was associated with longer hospitalization (7 vs 6 days; P < .001), but not increased mortality or morbidity. PP reduced POAF incidence (17.7% vs 31.3%; P = .001), especially after postoperative day 2 (time to POAF onset 41.9 vs 57.1 hours; P = .01). Age was associated with POAF. Female sex, coronary artery bypass grafting, beta blockers, and PP were inversely associated. CONCLUSIONS: POAF remains frequent after cardiac surgery. Hemodynamic instability is rare, although rapid ventricular response and need for electrical cardioversion are frequent. POAF burden is significant, and the arrhythmias resolve within 30 days. PP reduces POAF especially after postoperative day 2.

Deep Sternal Wound Infection and Mortality in Cardiac Surgery: A Meta-analysis.

BACKGROUND: Deep sternal wound infection (DSWI) is a rare but severe complication after cardiac surgical procedures and has been associated with increased early morbidity and mortality. Studies reporting long-term outcomes in patients with DSWI have shown contradictory results. We performed a study-level meta-analysis evaluating the impact of DSWI on short- and long-term clinical outcomes. METHODS: A systematic literature search was conducted to identify studies comparing short- and long-term outcomes of patients submitted to cardiac surgical procedures who developed DSWI and patients who did not. The primary outcome was overall mortality. Secondary outcomes were in-hospital mortality, follow-up mortality, major adverse cardiovascular events, myocardial infarction, and repeat revascularization. Postoperative outcomes were also investigated. RESULTS: Twenty-four studies totaling 407 829 patients were included. Overall, 6437 (1.6%) patients developed DSWI. Mean follow-up was 3.5 years. DSWI was associated with higher overall mortality (incidence rate ratio [IRR], 1.99; 95% CI, 1.66-2.38; P < .001), in-hospital mortality (odds ratio, 3.30; 95% CI, 1.88-5.81; P < .001), follow-up mortality (IRR, 2.02; 95% CI, 1.39-2.94; P = .001), and major adverse cardiovascular events (IRR, 2.04; 95% CI, 1.60-2.59; P < .001). No differences in myocardial infarction and repeat revascularization were found, but limited studies reported those outcomes. DSWI was associated with longer postoperative hospitalization, stroke, myocardial infarction, and respiratory and renal failure. Sensitivity analyses on isolated coronary artery bypass grafting studies and by adjustment method were consistent with the main analysis. CONCLUSIONS: Compared with patients who did not develop DSWI, patients with DSWI after cardiac surgical procedures had increased risk of death as well as short- and long-term adverse clinical outcomes.

Differences Among Clinical Trials and Registries on Surgical and Percutaneous Coronary Interventions.

BACKGROUND: A need exists for systematic evaluation of the differences in baseline characteristics and early outcomes between patients enrolled in randomized controlled trials (RCTs) and clinical practice for coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI). METHODS: Systematic searches were conducted to identify RCTs comparing CABG vs PCI and CABG or PCI registries. Sixteen predefined baseline characteristics and 30-day mortality were extracted from the included studies. Pooled proportion and mean with 95% CI were calculated for binary and continuous outcomes, respectively, by using the random effects model. RESULTS: Fourteen RCTs and 10 registries including more than 2 million patients were included. Registry patients who underwent CABG had a higher prevalence of hypertension, smoking, reduced left ventricular ejection fraction, and prior myocardial infarction, but a lower prevalence of single-vessel disease when compared with CABG-treated patients included in RCTs. Regarding PCI, hypertension, hyperlipidemia, left main coronary artery disease, triple-vessel coronary disease, and NYHA functional class

Sex differences in saphenous vein graft patency: A systematic review and meta-analysis.

BACKGROUND: Saphenous vein grafts (SVG) are the most commonly used conduits in coronary artery bypass grafting (CABG). Graft failure is observed in up to 50% of SVG at 10 years after surgery. Whether a difference in SVG patency rates exists between men and women remains unclear. METHODS: We performed a study-level meta-analysis to evaluate sex-related differences in follow-up patency rates of SVG after CABG. A systematic literature search was conducted to identify studies on CABG that reported follow-up SVG patency rates in men and women. The primary outcome was SVG patency rates by sex at follow-up. RESULTS: Seventeen studies totaling 8235 patients and 14,781 SVG grafts were included. There was no significant difference in follow-up SVG patency rates between men and women (incidence rate ratio 0.96, 95% confidence interval 0.90-1.03, p = .24), with mean angiographic follow-up of 33.5 months (standard deviation 29.2). Leave-one-out and cumulative analysis were consistent with the main analysis. We concluded that follow-up SVG patency rate is similar between men and women undergoing CABG.

Thoracoabdominal aortic aneurysmectomy in the high-risk patient.

OBJECTIVE: The study objective was to provide a review of outcomes and management strategies for high-risk scenarios in the open repair of thoracoabdominal aortic aneurysms. METHODS: Series examining the open repair of thoracoabdominal aortic aneurysms were reviewed to identify well-described high-risk scenarios and summarize expected outcomes and management strategies in the current era. RESULTS: The efforts of many have led to improved outcomes for patients undergoing the inherently challenging open repair of thoracoabdominal aortic pathologies. Several well-described high-risk scenarios include those related to preoperative comorbid conditions (preoperative pulmonary dysfunction, low ejection fraction, and renal dysfunction), anatomically high-risk cases (extent II repairs), and those with acute presentations (rupture, mycotic aneurysms, acute complicated type B aortic dissection). Several operative and perioperative techniques have been developed to mitigate the risk in these formidable cases. CONCLUSIONS: Challenges remain for several high-risk scenarios in thoracoabdominal aortic aneurysm repair. Judicious patient selection, meticulous surgical, and critical care strategies have greatly decreased the risk for many high-risk patients.

Aspiration thrombectomy for inferior vena cava tumor thrombus arising from hepatocellular carcinoma.

Pharmacomechanical therapy and catheter-directed thrombolysis have been shown to be very effective in the treatment of venous thromboembolism; however, there is much less data regarding inferior vena cava thrombi. Tumor thrombi pose an even greater clinical challenge as anti-coagulation and thrombolysis are not effective. We present the case of a 61-year-old male who presented with an inferior vena cava thrombus emanating from an accessory right hepatic vein, treated with aspiration thrombectomy.

Pericardial Effusion Provoking Atrial Fibrillation After Cardiac Surgery: JACC Review Topic of the Week.

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery. Patients who develop POAF are more likely to experience adverse outcomes, including increased rates of death, stroke, heart failure, and hospitalizations, and higher hospital costs. Understanding the mechanisms underlying POAF is important to improve patients' outcome and optimize health systems' efficiency. Beyond classic pathogenic hypotheses, emerging evidence suggests that postoperative pericardial effusion and localized pericardial inflammation may trigger POAF. This hypothesis is supported by data from nonhuman animal models and a growing body of evidence showing that reducing postoperative pericardial effusion might reduce POAF incidence. In this review, we summarize the classic pathophysiology theories of POAF following cardiac surgery and discuss new etiologic mechanisms with a specific focus on the role of pericardial effusion and inflammation.