Long-term antithrombotic therapy after coronary artery bypass grafting in patients with preoperative atrial fibrillation. A nationwide observational study from the SWEDEHEART registry

AIMS

To provide data guiding long-term antithrombotic therapy after coronary artery by-pass grafting (CABG) in patients with preoperative atrial fibrillation (AF).

METHODS AND RESULTS

From the SWEDEHEART registry, we included all patients, between January 2006 and September 2016, with preoperative AF and CHA₂DS₂-VASC score ≥2, undergoing CABG. Based on dispensed prescriptions 12 to 18 months after CABG, patients were divided in 3 groups: use of platelet inhibitors (PI) only, oral anticoagulant (OAC) only or a combination of OAC + PI. Outcomes were: Major adverse cardiac and cerebrovascular events (MACCE, [all-cause death, myocardial infarction, or stroke]), net adverse clinical events (NACE, [MACCE or bleeding]) and the individual components of NACE. Inverse probability of treatment weighting was used to adjust for the non-randomized study design. Among 2,564 patients, 1,040 (41%) were treated with PI alone, 1,064 (41%) with OAC alone, and 460 (18%) with PI + OAC. Treatment with PI alone was associated with higher risk for MACCE (adjusted HR 1.43, 95% CI 1.09-1.88), driven by higher risk for stroke and MI, compared with OAC alone. Treatment with PI + OAC, was associated with higher risk for NACE (adjusted HR 1.40, 95% CI 1.06-1.85), driven by higher risk for bleeds, compared with OAC alone.

CONCLUSION

In this real-world observational study, a high proportion of patients with AF, undergoing CABG, did not receive a long-term OAC therapy. Treatment with OAC alone was associated with a net clinical benefit, compared with PI alone or PI + OAC.

Medical therapy after surgical aortic valve replacement for aortic regurgitation

OBJECTIVE

Current clinical guidelines have no specific recommendations regarding medical therapy after surgical aortic valve replacement in patients with aortic regurgitation. We studied the association between medical therapy with RAS inhibitors, statins and beta-blockers, and long-term major adverse cardiovascular events.

METHODS

All patients undergoing valve replacement due to aortic regurgitation between 2006-2017 in Sweden and alive six months after discharge were included. Time-dependent multivariable Cox regression models adjusted for age, sex, patient characteristics, comorbidities, other medications, and year of SAVR were used. Primary outcome was a composite of all-cause mortality, myocardial infarction, and stroke. Subgroup analyses based on age, sex, heart failure, low ejection fraction, hyperlipidaemia, and hypertension were performed.

RESULTS

A total of 2,204 patients were included (median follow-up 5.0 years (range 0.0-11.5)). At baseline, 68% of the patients were dispensed RAS inhibitors, 80% beta-blockers, and 35% statins. Dispense of RAS inhibitors and beta-blockers declined over time, especially during the first year after baseline, while dispense of statins remained stable. Treatment with RAS inhibitors or statins was associated with a reduced risk of the primary outcome (aHR 0.71, 95%CI 0.57-0.87 and aHR 0.78, 95%CI 0.62-0.99, respectively). The results were consistent in subgroups based on age, sex, and comorbidities. Beta-blocker treatment was associated with an increased risk for the primary outcome (aHR 1.35, 95%CI 1.07-1.70).

CONCLUSIONS

The results indicate a potential beneficial association of RAS inhibitors and statins as part of a secondary preventive treatment regime after aortic valve replacement in patients with aortic regurgitation. The role of beta-blockers needs to be further investigated.

Risk factors and treatment of oxygenator high-pressure excursions during cardiopulmonary bypass

INTRODUCTION

A high-pressure excursion (HPE) is a sudden increase in oxygenator inlet pressure during cardiopulmonary bypass (CPB). The aims of this study were to identify factors associated with HPE, to describe a treatment protocol utilizing epoprostenol in severe cases, and to assess early outcome in HPE patients.

METHODS

Patients who underwent cardiac surgery with cardiopulmonary bypass at Sahlgrenska University Hospital 2016-2018 were included in a retrospective observational study. Pre- and post-operative data collected from electronic health records, local databases, and registries were compared between HPE and non-HPE patients. Factors associated with HPE were identified with logistic regression models.

RESULTS

In total, 2024 patients were analyzed, and 37 (1.8%) developed HPE. Large body surface area (adjusted Odds Ratio (aOR): 1.43 per 0.1 m²; 95% confidence interval (CI): 1.16-1.76, p < 0.001), higher hematocrit during CPB (aOR: 1.20 per 1%; (1.09-1.33), p < 0.001), acute surgery (aOR: 2.98; (1.26-6.62), p = 0.018), and previous stroke (aOR: 2.93; (1.03-7.20), p = 0.027) were independently associated with HPE. HPE was treated with hemodilution (n = 29, 78.4%), and/or extra heparin (n = 23, 62.2%), and/or epoprostenol (n = 12, 32.4%). No oxygenator change-out was necessary. While there was no significant difference in 30-day mortality (2.7% vs 3.2%, p = 1.0), HPE was associated with a higher perioperative stroke rate (8.1% vs 1.8%, aOR 5.09 (1.17-15.57), p = 0.011).

CONCLUSIONS

Large body surface area, high hematocrit during CPB, previous stroke and acute surgery were independently associated with HPE. A treatment protocol including epoprostenol appears to be a safe option. Perioperative stroke rate was increased in HPE patients.

Patients' motivation to undergo transcatheter aortic valve replacement. A phenomenological hermeneutic study

BACKGROUND

Aortic stenosis is the most common valvular disease, and its prevalence is increasing due to the ageing population. Transcatheter aortic valve replacement (TAVR) is the recommended method when treating frail, older patients. Knowledge of what motivates older patients to undergo TAVR is important, in order to meet patients' expectations.

OBJECTIVE

The study aimed to explore the meaning of older patients' motivation to undergo TAVR.

DESIGN AND METHODS

The design was a qualitative study, analysed using a phenomenological hermeneutic approach. In-depth, semi-structured interviews with open-ended questions were conducted. Participants were selected from a specialist cardiology clinic in Sweden. Eighteen patients, six women and twelve men, aged 66-92, were recruited.

RESULTS

The analysis showed that patients who had agreed to undergo TAVR were deeply affected by their body's failure. Before the TAVR procedure, the participants were limited in their daily activities and experienced that their life was on hold. They experienced that they were barely existing. They were aware of their life-threatening condition and were forced to confront death. Yet despite an advanced age, they still had considerable zest for life. It was very important to them to remain independent in everyday life, and fear of becoming dependent had a strong impact on their motivations for undergoing TAVR.

CONCLUSION

Older patients' motivations to undergo TAVR are strongly influenced by their fear of being dependent on others and their zest for life. Health care professionals need to support these patients in setting realistic and personalised goals.

IMPLICATION FOR PRACTICE

Person-centered care actions could facilitate patients' involvement in the decision about TAVR and strenghten patients' beliefs in their own capabilities, before and after TAVR.

Temperature effects on incidence of surgery for acute type A aortic dissection in the Nordics

We aimed to investigate a hypothesised association between daily mean temperature and the risk of surgery for acute type A aortic dissection (ATAAD). For the period of 1 January 2005 until 31 December 2019, we collected daily data on mean temperatures and date of 2995 operations for ATAAD at 10 Nordic cities included in the Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) collaboration. Using a two-stage time-series approach, we investigated the association between hot and cold temperatures relative to the optimal temperature and the rate of ATAAD repair in the selected cities. The relative risks (RRs) of cold temperatures (≤-5°C) and hot temperatures (≥21°C) compared to optimal temperature were 1.47 (95% CI: 0.72-2.99) and 1.43 (95% CI: 0.67-3.08), respectively. In line with previous studies, we observed increased risk at cold and hot temperatures. However, the observed associations were not statistically significant, thus only providing weak evidence of an association.

Impact of national holidays and weekends on incidence of acute type A aortic dissection repair

Previous studies have demonstrated that environmental and temporal factors may affect the incidence of acute type A aortic dissection (ATAAD). Here, we aimed to investigate the hypothesis that national holidays and weekends influence the incidence of surgery for ATAAD. For the period 1st of January 2005 until 31st of December 2019, we investigated a hypothesised effect of (country-specific) national holidays and weekends on the frequency of 2995 surgical repairs for ATAAD at 10 Nordic cities included in the Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) collaboration. Compared to other days, the number of ATAAD repairs were 29% (RR 0.71; 95% CI 0.54-0.94) lower on national holidays and 26% (RR 0.74; 95% CI 0.68-0.82) lower on weekends. As day of week patterns of symptom duration were assessed and the primary analyses were adjusted for period of year, our findings suggest that the reduced surgical incidence on national holidays and weekends does not seem to correspond to seasonal effects or surgery being delayed and performed on regular working days.

Perioperative stroke and survival in coronary artery bypass grafting patients: a SWEDEHEART study

OBJECTIVES

Perioperative stroke is a severe complication of cardiac surgery. We assessed the incidence of stroke over time, the association between stroke and mortality and identified preoperative factors independently associated with perioperative stroke, in a large nationwide cardiac surgery population.

METHODS

All patients who underwent coronary artery bypass grafting in Sweden 2006-2017 were included in a registry-based observational cohort study based on prospectively collected data. Multivariable logistic and Cox regression models were used to assess associations between perioperative stroke and mortality and to identify factors associated with stroke. The median follow-up was 6 years (range 0-12).

RESULTS

There were 441 perioperative strokes in 36 898 patients. The mean incidence was 1.2% and decreased marginally over time [adjusted odds ratio (OR) 0.97 per year (95% confidence interval 0.94-1.00), P = 0.035]. Stroke patients had a higher overall mortality risk during follow-up [adjusted hazard ratio 2.30 (2.00-2.64), P < 0.001], with the highest risk during the first 30 postoperative days [adjusted hazard ratio (7.29 (5.58-9.54), P < 0.001]. The strongest independent preoperative factors associated with stroke were prior cardiac surgery [adjusted OR 2.89 (1.40-5.96)], critical preoperative condition [adjusted OR 2.55 (1.73-3.76)], previous stroke [adjusted OR 1.77 (1.35-2.33)], preoperative angina requiring intravenous nitrates [adjusted OR 1.67 (1.28-2.17)], peripheral vascular disease [OR 1.63 (1.25-2.13)] and advanced age [OR 1.05 (1.03-1.06) per year].

CONCLUSIONS

The incidence of perioperative stroke after coronary artery bypass grafting has remained stable. Patients with perioperative stroke had a markedly higher adjusted risk of death early after surgery. The risk declined over time but remained higher during the entire follow-up period.

Beta blockers and long-term outcome after coronary artery bypass grafting: a nationwide observational study

Aims

Beta blockers are associated with improved outcomes for selected patients with cardiovascular disease. We assessed long-term utilization of beta blockers after coronary artery bypass grafting (CABG) and its association with outcome.

Methods and results

All 35 184 patients in Sweden who underwent first-time isolated CABG between 1 January 2006 and 31 December 2017 and were followed for at least 6 months were included in a nationwide observational study. Multivariable Cox regression models using time-updated data on dispensed prescriptions were used to assess associations between different types of beta blockers and outcomes. The primary outcome was major adverse cardiovascular events (MACEs), a composite of all-cause mortality, stroke, and myocardial infarction (MI). Subgroup analyses were performed in patients with and without previous MI, heart failure, and reduced left ventricular ejection fraction (LVEF). Median follow-up was 5.2 years (range 0–11). At baseline, 33 159 (94.2%) patients were dispensed beta blockers, 30 563 (92.2%) of which were cardioselective beta blockers. After 10 years, the dispensing of cardioselective beta blockers had declined to 73.7% of all patients. Ongoing treatment with cardioselective beta blockers was associated with a slight reduction in MACEs [hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.89–0.98, P = 0.0063]. The reduction was largely driven by a reduced risk of MI (HR 0.83, 95% CI 0.75–0.92, P = 0.0003), while there was no significant reduction in all-cause mortality (HR 0.99, 95% CI 0.93–1.05) and stroke (HR 0.96, 95% CI 0.87–1.05). The reduced risk for MI was consistent in all the investigated subgroups.

Conclusion

Ongoing treatment with cardioselective beta blockers after CABG is associated with a reduction in MACEs, mainly because of reduced long-term risk for MI. The association between cardioselective beta blockers and MI was consistent in patients with and patients without previous MI, heart failure, atrial fibrillation, or reduced LVEF.

Human intracardiac SSEA4+CD34 cells show features of cycling, immature cardiomyocytes and are distinct from Side Population and C-kit+CD45- cells

Cardiomyocyte proliferation has emerged as the main source of new cardiomyocytes in the adult. Progenitor cell populations may on the other hand contribute to the renewal of other cell types, including endothelial and smooth muscle cells. The phenotypes of immature cell populations in the adult human heart have not been extensively explored. We therefore investigated whether SSEA4+CD34- cells might constitute immature cycling cardiomyocytes in the adult failing and non-failing human heart. The phenotypes of Side Population (SP) and C-kit+CD45- progenitor cells were also analyzed. Biopsies from the four heart chambers were obtained from patients with end-stage heart failure as well as organ donors without chronic heart failure. Freshly dissociated cells underwent flow cytometric analysis and sorting. SSEA4+CD34- cells expressed high levels of cardiomyocyte, stem cell and proliferation markers. This pattern resembles that of cycling, immature, cardiomyocytes, which may be important in endogenous cardiac regeneration. SSEA4+CD34- cells isolated from failing hearts tended to express lower levels of cardiomyocyte markers as well as higher levels of stem cell markers. C-kit+CD45- and SP CD45- cells expressed high levels of endothelial and stem cell markers–corresponding to endothelial progenitor cells involved in endothelial renewal.

pH-Dependent Protonation of Histidine Residues Is Critical for Electrostatic LDL (Low-Density Lipoprotein) Binding to Human Coronary Arteries

BACKGROUND

The initiating step in atherogenesis is the electrostatic binding of LDL (low-density lipoprotein) to proteoglycan glycosaminoglycans in the arterial intima. However, although proteoglycans are widespread throughout the intima of most coronary artery segments, LDL is not evenly distributed, indicating that LDL retention is not merely dependent on the presence of proteoglycans. We aim to identify factors that promote the interaction between LDL and the vessel wall of human coronary arteries.

METHODS

We developed an ex vivo model to investigate binding of human-labeled LDL to human coronary artery sections without the interference of cellular processes.

RESULTS

By staining consecutive sections of human coronary arteries, we found strong staining of sulfated glycosaminoglycans throughout the arterial intima, whereas endogenous LDL deposits were focally distributed. Ex vivo binding of LDL was uniform in all intimal areas with sulfated glycosaminoglycans. However, lowering the pH from 7.4 to 6.5 triggered a 35-fold increase in LDL binding. The pH-dependent binding was abolished by pretreating LDL with diethyl-pyrocarbonate, which blocks the protonation of histidine residues, or cyclohexanedione, which inhibits the positive charge of site B on LDL. Thus, both histidine protonation and site B are required for strong electrostatic LDL binding to the intima.

CONCLUSIONS

This study identifies histidine protonation as an important component for electrostatic LDL binding to human coronary arteries. Our findings show that the local pH will have a profound impact on LDL's affinity for sulfated glycosaminoglycans, which may influence the retention and accumulation pattern of LDL in the arterial vasculature.

Associations between medical therapy after surgical aortic valve replacement for aortic stenosis and long-term mortality: a report from the SWEDEHEART registry

AIMS

The association between the use of statins, renin-angiotensin system (RAS) inhibitors, and/or β-blockers and long-term mortality in patients with aortic stenosis (AS) who underwent surgical aortic valve replacement (SAVR) is unknown.

METHODS AND RESULTS

All patients with AS who underwent isolated first-time SAVR in Sweden from 2006 to 2017 and survived 6 months after discharge were included. Individual patient data from four mandatory nationwide registries were merged. Cox proportional hazards models, with time-updated data on medication status and adjusted for age, sex, comorbidities, type of prosthesis, and year of surgery, were used to investigate associations between dispensed statins, RAS inhibitors, and β-blockers and all-cause mortality. In total, 9553 patients were included, and the median follow-up time was 4.9 years (range 0-11); 1738 patients (18.2%) died during follow-up. Statins were dispensed to 49.1% and 49.0% of the patients within 6 months of discharge from the hospital and after 10 years, respectively. Corresponding figures were 51.4% and 53.9% for RAS inhibitors and 79.3% and 60.7% for β-blockers. Ongoing treatment was associated with lower mortality risk for statins {adjusted hazard ratio (aHR) 0.67 [95% confidence interval (95% CI) 0.60-0.74]; P < 0.001} and RAS inhibitors [aHR 0.84 (0.76-0.93); P < 0.001] but not for β-blockers [aHR 1.17 (1.05-1.30); P = 0.004]. The associations were robust in subgroups based on age, sex, and comorbidities (P for interactions >0.05).

CONCLUSIONS

The results of this large population-based real-world study support the use of statins and RAS inhibitors for patients who underwent SAVR due to AS.

Stroke Risk Stratification in Patients With Postoperative Atrial Fibrillation After Coronary Artery Bypass Grafting

Background

The CHA₂DS₂‐VASc (congestive heart failure, hypertension, age ≥75 years, diabetes, previous stroke or TIA [transient ischemic attack], vascular disease, age 65 to 74 years, sex category female; 2 indicates 2 points, otherwise 1 point) scoring system is recommended to guide decisions on oral anticoagulation therapy for stroke prevention in patients with nonsurgery atrial fibrillation. A score ≥1 in men and ≥2 in women, corresponding to an annual stroke risk exceeding 1%, warrants long‐term oral anticoagulation provided the bleeding risk is acceptable. However, in patients with new‐onset postoperative atrial fibrillation, the optimal risk stratification method is unknown. The aim of this study was therefore to evaluate the CHA₂DS₂‐VASc scoring system for estimating the 1‐year ischemic stroke risk in patients with new‐onset postoperative atrial fibrillation after coronary artery bypass grafting.

Methods and Results

All patients with new‐onset postoperative atrial fibrillation and without oral anticoagulation after first‐time isolated coronary artery bypass grafting performed in Sweden during 2007 to 2017 were eligible for this registry‐based observational cohort study. The 1‐year ischemic stroke rate at each step of the CHA₂DS₂‐VASc score was estimated using a Kaplan‐Meier estimator. Of the 6368 patients included (mean age, 69.9 years; 81% men), >97% were treated with antiplatelet drugs. There were 147 ischemic strokes during the first year of follow‐up. The ischemic stroke rate at 1 year was 0.3%, 0.7%, and 1.5% in patients with CHA₂DS₂‐VASc scores of 1, 2, and 3, respectively, and ≥2.3% in patients with a score ≥4. A sensitivity analysis, with the inclusion of patients on anticoagulants, was performed and supported the primary results.

Conclusions

Patients with new‐onset atrial fibrillation after coronary artery bypass grafting and a CHA₂DS₂‐VASc score <3 have such a low 1‐year risk for ischemic stroke that oral anticoagulation therapy should probably be avoided.

Data Mining Identifies CCN2 and THBS1 as Biomarker Candidates for Cardiac Hypertrophy

Cardiac hypertrophy is a condition that may contribute to the development of heart failure. In this study, we compare the gene-expression patterns of our in vitro stem-cell-based cardiac hypertrophy model with the gene expression of biopsies collected from hypertrophic human hearts. Twenty-five differentially expressed genes (DEGs) from both groups were identified and the expression of selected corresponding secreted proteins were validated using ELISA and Western blot. Several biomarkers, including CCN2, THBS1, NPPA, and NPPB, were identified, which showed significant overexpressions in the hypertrophic samples in both the cardiac biopsies and in the endothelin-1-treated cells, both at gene and protein levels. The protein-interaction network analysis revealed CCN2 as a central node among the 25 overlapping DEGs, suggesting that this gene might play an important role in the development of cardiac hypertrophy. GO-enrichment analysis of the 25 DEGs revealed many biological processes associated with cardiac function and the development of cardiac hypertrophy. In conclusion, we identified important similarities between ET-1-stimulated human-stem-cell-derived cardiomyocytes and human hypertrophic cardiac tissue. Novel putative cardiac hypertrophy biomarkers were identified and validated on the protein level, lending support for further investigations to assess their potential for future clinical applications.

Serum biomarkers of brain injury after uncomplicated cardiac surgery: Secondary analysis from a randomized trial

Background

Postoperative cognitive dysfunction is common after cardiac surgery. Postoperative measurements of brain injury biomarkers may identify brain damage and predict cognitive dysfunction. We describe the release patterns of five brain injury markers in serum and plasma after uncomplicated cardiac surgery.

Methods

Sixty‐one elective cardiac surgery patients were randomized to undergo surgery with either a dextran‐based prime or a crystalloid prime. Blood samples were taken immediately before surgery, and 2 and 24 h after surgery. Concentrations of the brain injury biomarkers S100B, glial fibrillary acidic protein (GFAP), tau, neurofilament light (NfL) and neuron‐specific enolase (NSE)) and the blood–brain barrier injury marker β‐trace protein were analyzed. Concentrations of brain injury biomarkers were correlated to patients’ age, operation time, and degree of hemolysis.

Results

No significant difference in brain injury biomarkers was observed between the prime groups. All brain injury biomarkers increased significantly after surgery (tau +456% (25th–75th percentile 327%−702%), NfL +57% (28%−87%), S100B +1145% (783%−2158%), GFAP +17% (−3%−43%), NSE +168% (106%−228%), while β‐trace protein was reduced (−11% (−17−3%). Tau, S100B, and NSE peaked at 2h, NfL and GFAP at 24 h. Postoperative concentrations of brain injury markers correlated to age, operation time, and/or hemolysis.

Conclusion

Uncomplicated cardiac surgery with cardiopulmonary bypass is associated with an increase in serum/plasma levels of all the studied injury markers, without signs of blood–brain barrier injury. The biomarkers differ markedly in their levels of release and time course. Further investigations are required to study associations between perioperative release of biomarkers, postoperative cognitive function and clinical outcome.

Risk of depression after coronary artery bypass grafting: a SWEDEHEART population-based cohort study

Aims

A diagnosis of depression in patients with coronary heart disease is associated with worse outcomes. This study examined the long-term risk for new onset of depression after coronary artery bypass grafting (CABG) compared to an age- and sex-matched control group from the general population.

Methods and results

In total, 125 418 primary isolated CABG patients and 495 371 matched controls were included from 1992 to 2017. The SWEDEHEART registry and three other national registers were used to acquire information about baseline characteristics and depression. The adjusted risk of depression was estimated by using Cox regression models adjusted for patient characteristics, and socioeconomic variables, described by hazard ratios (HR) and 95% confidence intervals (CI). In total, 6202 (4.9%) CABG patients and 17 854 (3.6%) controls developed depression. The cumulative incidence of depression was higher in CABG patients than in the control population [6.1%, 95% CI 6.0–6.3 vs. 4.7% (4.7–4.8), P < 0.0001]. Overall, the CABG group had a marginally increased adjusted risk of depression compared to controls [adjusted HR (aHR): 1.05 (1.01–1.09), P = 0.0091]. In age-specific analyses, the increased risk compared to controls was only present in patients <65 years [aHR: 1.19 (1.11–1.27), P <0.0001] and was only evident during the first 5 years after surgery.

Conclusion

Patients who underwent CABG had a higher risk of new onset of depression compared to sex- and age-matched controls in the general population. The risk of depression was especially pronounced in younger patients during the first 5 years after surgery.