TREM2 protects from atherosclerosis by limiting necrotic core formation.

Atherosclerosis is a chronic disease of the vascular wall driven by lipid accumulation and inflammation in the intimal layer of arteries, and its main complications, myocardial infarction and stroke, are the leading cause of mortality worldwide [1], [2]. Recent studies have identified Triggering receptor expressed on myeloid cells 2 (TREM2), a lipid-sensing receptor regulating myeloid cell functions [3], to be highly expressed in macrophage foam cells in experimental and human atherosclerosis [4]. However, the role of TREM2 in atherosclerosis is not fully known. Here, we show that hematopoietic or global TREM2 deficiency increased, whereas TREM2 agonism decreased necrotic core formation in early atherosclerosis. We demonstrate that TREM2 is essential for the efferocytosis capacities of macrophages, and to the survival of lipid-laden macrophages, indicating a crucial role of TREM2 in maintaining the balance between foam cell death and clearance of dead cells in atherosclerotic lesions, thereby controlling plaque necrosis.

Combined Effects of Clonal Hematopoiesis and Carotid Stenosis on Cardiovascular Mortality.

BACKGROUND: The expansion of hematopoietic stem cells caused by acquired somatic mutations (clonal hematopoiesis [CH]) is a novel cardiovascular risk factor. The prognostic value of CH in patients with carotid atherosclerosis remains to be evaluated. OBJECTIVES: This study assessed the prognostic significance of CH in patients with atherosclerosis as detected by ultrasound of the carotid artery. METHODS: We applied deep sequencing of selected genomic regions within the genes DNMT3A, TET2, ASXL1, and JAK2 to screen for CH in 968 prospectively collected patients with asymptomatic carotid atherosclerosis evaluated by duplex sonography. RESULTS: We detected clonal markers at variant allele frequency ≥2% in 133 (13.7%) of 968 patients (median age 69.2 years), with increasing prevalence at advanced age. Multivariate analyses including age and established cardiovascular risk factors revealed overall presence of CH to be significantly associated with increased risk of cardiovascular death (HR: 1.50; 95% CI: 1.12-2.00; P = 0.007), reflected also at the single gene level. The effect of CH was more pronounced in older patients and independent of the patients' inflammatory status as measured by high-sensitivity C-reactive protein. Simultaneous assessment of CH and degree of carotid stenosis revealed combined effects on cardiovascular mortality, depicted by a superior risk for patients with >50% stenosis and concomitant CH (adjusted HR: 1.60; 95% CI: 1.08-2.38; P = 0.020). CONCLUSIONS: CH status in combination with the extent of carotid atherosclerosis jointly predict long-term mortality. Determination of CH can provide additional prognostic information in patients with asymptomatic carotid atherosclerosis.

Metabolomics implicate eicosanoids in severe functional mitral regurgitation.

AIMS: Secondary, or functional, mitral regurgitation (FMR) was recently recognized as a separate clinical entity, complicating heart failure with reduced ejection fraction (HFrEF) and entailing particularly poor outcome. Currently, there is a lack of targeted therapies for FMR due to the fact that pathomechanisms leading to FMR progression are incompletely understood. In this study, we sought to perform metabolomic profiling of HFrEF patients with severe FMR, comparing results to patients with no or mild FMR. METHODS AND RESULTS: Targeted plasma metabolomics and untargeted eicosanoid analyses were performed in samples drawn from HFrEF patients (n = 80) on optimal guideline-directed medical therapy. Specifically, 17 eicosanoids and 188 metabolites were analysed. Forty-seven patients (58.8%) had severe FMR, and 33 patients (41.2%) had no or non-severe FMR. Comparison of eicosanoid levels between groups, accounting for age, body mass index, and sex, revealed significant up-regulation of six eicosanoids (11,12-EET, 13(R)-HODE, 12(S)-HETE, 8,9-DiHETrE, metPGJ2, and 20-HDoHE) in severe FMR patients. Metabolites did not differ significantly. In patients with severe FMR, but not in those without severe FMR, levels of 8,9-DiHETrE above a cut-off specified by receiver-operating characteristic analysis independently predicted all-cause mortality after a median follow-up of 43 [interquartile range 38, 48] months [hazard ratio 12.488 (95% confidence interval 3.835-40.666), P < 0.0001]. CONCLUSIONS: We report the up-regulation of various eicosanoids in patients with severe FMR, with 8,9-DiHETrE appearing to predict mortality. Our observations may serve as a nucleus for further investigations into the causes and consequences of metabolic derangements in this important valvular abnormality.

APRIL limits atherosclerosis by binding to heparan sulfate proteoglycans.

Atherosclerotic cardiovascular disease causes heart attacks and strokes, which are the leading causes of mortality worldwide1. The formation of atherosclerotic plaques is initiated when low-density lipoproteins bind to heparan-sulfate proteoglycans (HSPGs)2 and become trapped in the subendothelial space of large and medium size arteries, which leads to chronic inflammation and remodelling of the artery wall2. A proliferation-inducing ligand (APRIL) is a cytokine that binds to HSPGs3, but the physiology of this interaction is largely unknown. Here we show that genetic ablation or antibody-mediated depletion of APRIL aggravates atherosclerosis in mice. Mechanistically, we demonstrate that APRIL confers atheroprotection by binding to heparan sulfate chains of heparan-sulfate proteoglycan 2 (HSPG2), which limits the retention of low-density lipoproteins, accumulation of macrophages and formation of necrotic cores. Indeed, antibody-mediated depletion of APRIL in mice expressing heparan sulfate-deficient HSPG2 had no effect on the development of atherosclerosis. Treatment with a specific anti-APRIL antibody that promotes the binding of APRIL to HSPGs reduced experimental atherosclerosis. Furthermore, the serum levels of a form of human APRIL protein that binds to HSPGs, which we termed non-canonical APRIL (nc-APRIL), are associated independently of traditional risk factors with long-term cardiovascular mortality in patients with atherosclerosis. Our data reveal properties of APRIL that have broad pathophysiological implications for vascular homeostasis.

Von Willebrand factor antigen levels predict major adverse cardiovascular events in patients with carotid stenosis of the ICARAS study.

BACKGROUND AND AIMS: Von Willebrand factor (VWF) plays an important role in thrombogenesis and mediates platelet adhesion particularly under high shear stress. Such conditions are generally found in stenotic arteries and can eventually cause myocardial infarction or stroke. We aimed to study whether levels of VWF antigen (VWF:Ag) predict future major adverse cardiovascular events (MACE) in patients suffering from carotid artery stenosis. METHODS: Patients with atherosclerotic carotid artery disease defined by the presence of nonstenotic plaques or any degree of carotid stenosis were prospectively enrolled. Concentrations of VWF were measured by enzyme immunoassay. RESULTS: VWF:Ag levels were more stable after 4 freeze-thaw cycles, when compared to VWF activity, and we showed similar concentrations of VWF in citrated plasma and serum (±4%). Levels of VWF:Ag predicted future cardiovascular events in 811 patients with carotid stenosis independent of known cardiovascular risk factors. Patients with VWF:Ag concentrations in the 4th quartile had a 44% event rate after an average 3-year follow up and a hazard ratio of 2.15 (95% confidence interval 1.46-3.16; p < 0.001). CONCLUSIONS: High concentrations of VWF:Ag predict major cardiovascular events in patients with carotid stenosis, and given their high event rate may be useful for risk stratification of such patients.

Carotid ultrasound investigation as a prognostic tool for patients with diabetes mellitus.

BACKGROUND: Experimental and clinical data indicate a major influence of diabetes on atherogenesis. We aimed to assess whether the effect of diabetes on long-term mortality in asymptomatic patient with carotid stenosis is contingent upon the degree of the carotid atherosclerotic burden. METHODS: 1065 patients with neurological asymptomatic carotid atherosclerosis as evaluated by duplex sonography were prospectively followed for cause-specific mortality. RESULTS: During a median of 11.8 years, a total of 549 deaths, including 362 cardiovascular deaths, were recorded. Diabetes and glycohemoglobin A1c (Hba1c) levels were significantly associated with mortality. Diabetes displayed an independent risk for all-cause (adjusted HR 1.62; 95% CI 1.35-1.94) and cardiovascular death (adjusted HR 1.75, 95% CI 1.40-2.19). The adjusted hazard ratio per increase of 1% of Hba1c levels was 1.21 (P < 0.01) for all-cause and 1.31 (P < 0.01) for cardiovascular mortality, respectively. Patients with diabetes mellitus and a higher degree of carotid stenosis and were at great risk of adverse outcome. Only 21% of the asymptomatic diabetic patients with carotid narrowing over 50% survived, whereas 62% of the patients without diabetes and with carotid atherosclerosis below 50% were still alive after 12-years of follow-up. The high risk for all-cause and cardiovascular death of these patients remained significant after adjustment for various established cardiovascular risk factors in multivariable regression analysis (adjusted hazard ratio 2.4, P < 0.001; compared to patients without diabetes and < 50% carotid atherosclerosis). CONCLUSION: Diabetic patients with carotid stenosis ≥ 50% are at exceptional high risk for all-cause and cardiovascular death. Thus, routinely ultrasound investigation of the carotid arteries might be a valuable prognostic tool for patients with diabetes mellitus.

The prognostic value of serum amyloid A for long-term mortality among patients with subclinical carotid atherosclerosis.

BACKGROUND AND PURPOSE: Despite extensive research in the last decade, the role of serum amyloid A (SAA) in atherogenesis remains highly controversial. The aim of this study was therefore to assess whether SAA is associated with long-term mortality in patients with subclinical carotid artery disease. METHODS: One thousand sixty-five patients with neurological asymptomatic carotid atherosclerosis as evaluated by duplex sonography were prospectively followed for cause-specific mortality. RESULTS: During a median of 11.8 years, a total of 549 deaths, including 362 cardiovascular deaths, were recorded. Patients who died within the follow-up period had significantly higher baseline SAA serum levels compared to those who survived (12.9 vs 9.5 mg/dL; P < 0.001). In univariable Cox regression analysis, the risk of all-cause and cardiovascular mortality significantly increased in patients with elevated serum levels of SAA (crude hazard ratio for cardiovascular mortality per increase of 1 SD of SAA levels was 1.14, 95% CI 1.08-1.22], P < 0.0001). However, SAA lost its significance after adjusting for high-sensitivity C-reactive protein (hsCRP), suggesting that SAA might not be directly associated with atherogenesis, but rather be a mere reflection of the individual patient's inflammatory status. CONCLUSIONS: Serum amyloid A is not independently associated with (cardiovascular) mortality in patients with subclinical carotid atherosclerosis.

Combined Effects of Inflammatory Status and Carotid Atherosclerosis: A 12-Year Follow-Up Study.

BACKGROUND AND PURPOSE: Inflammatory responses play a key role in atherogenesis. The aim of this study was to assess the prognostic value of hsCRP (high-sensitivity C-reactive protein) and to evaluate whether degree of carotid stenosis and serum levels of hsCRP jointly predict long-term mortality in asymptomatic patients with carotid atherosclerosis. METHODS: One thousand sixty-five patients with neurological asymptomatic carotid atherosclerosis as evaluated by duplex sonography were prospectively followed for cause-specific mortality. RESULTS: During a median of 11.81 years, a total of 549 deaths, including 362 cardiovascular deaths, were recorded. The risk of all-cause and cardiovascular mortality significantly increased in patients with elevated serum levels of hsCRP (the adjusted hazard ratio for cardiovascular mortality per increase of 1 mg/dL of hsCRP levels was 1.47; P<0.001). Patients with a high degree of carotid stenosis and increased hsCRP levels were particularly at risk of adverse outcome. Patients with carotid narrowing over 50% and hsCRP levels >0.29 mg/dL (=median) had nearly twice as high a risk of cardiovascular mortality compared with patients with carotid stenosis of <50% and hsCRP levels <0.29 mg/dL (adjusted hazard ratio 1.89; P<0.001). Improvement in risk stratification with combined assessment of carotid stenosis and hsCRP was confirmed by an improvement of the continuous net reclassification improvement with 18% for all-cause mortality and 15% for cardiovascular mortality compared with the degree of carotid stenosis alone (P<0.01). CONCLUSIONS: Measurement of hsCRP in combination with ultrasound investigations of the carotid arteries at a single time point provides additional prognostic information for patients with asymptomatic carotid atherosclerosis.

Percutaneous instillation of physiological saline solution for the treatment of femoral pseudoaneuryms.

OBJECTIVE: To investigate the efficacy of para-aneurysmal saline injection for closure of postcatheterization pseudo-aneurysm (PA) at the vascular access site. METHODS: Fifty-one consecutive patients with postcatheterization PA at the vascular access site were included to undergo percutaneous para-aneurysmal saline injection. In case of technical failure the day after, PA were treated by bovine thrombin injection. Anatomical properties of the PA were recorded as were details to injection. RESULTS: Initially all patients exhibited success which was reduced to 43 % at day one. A saline volume of median 7 ml (interquartile range 6-8 ml) has been injected. The amount of injected saline was not different in patients with and without treatment success at day one (P = 0.6). Several anatomical properties of the PA exhibited marked differences in patients with or without success. The length (10.3 mm (7.8-12.0) vs. 12.5 mm (10.3-15.0); P = 0.009) and the angulation (110° (100-118) vs. 140° (129-146); P < 0.001) of the fistula/vessel axis was statistically different between groups. The peak systolic velocity failed to show significance with a tendency to higher values in the ineffective study group (P = 0.07). No peripheral complications occurred. CONCLUSION: Para-aneurysmal saline injection may be a therapeutic alternative to percutaneous thrombin injection in patients exhibiting favorable anatomical properties.

Red cell distribution width and mortality in carotid atherosclerosis.

BACKGROUND: Red cell distribution width (RDW) is associated with morbidity and mortality in chronic cardiac disease. The aim of the present study was to investigate the role of RDW as a predictor of adverse outcome in patients with carotid atherosclerosis. MATERIALS AND METHODS: We prospectively studied 1065 of 1286 consecutive patients with neurological asymptomatic carotid artery stenosis as assessed by duplex Doppler sonography. The study end points were all-cause mortality and cardiovascular mortality respectively. RESULTS: During a median follow-up time of 6·2 years (interquartile range 5·9-6·6), corresponding to 5551 overall person-years, 275 patients (25·8%) died. Of them, 182 patients (66·2%) died due to cardiovascular causes. RDW was significantly associated with adverse outcome. In a continuous multivariate Cox regression analysis, the adjusted hazard ratio for each per cent increase in RDW was 1·39 (95% CI 1·27-1·53; P < 0·001) for all-cause and 1·43 (95% CI 1·28-1·60; P < 0·001) for cardiovascular mortality respectively. Kaplan-Meier estimates showed a gradual relationship between increasing quartiles of RDW and death (log rank P < 0·001). Adjusted hazard ratios for all-cause death ranged from 0·89 to 1·94 for the highest vs. the lowest quartile (P < 0·001 for trend) and for cardiovascular death from 1·08 to 2·34 for the highest vs. the lowest quartile (P < 0·001 for trend) respectively. CONCLUSIONS: Red cell distribution width was significantly and independently associated with all-cause and cardiovascular death in patients with asymptomatic carotid atherosclerosis.

The impact of selectins on mortality in stable carotid atherosclerosis.

Cellular adhesion molecules also known as selectins promote recruitment of inflammatory cells into the arterial wall where they interact with lipid particles leading subsequently to plaque formation. The intercellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1) and the endothelial-leukocyte adhesion molecule 1 (ELAM-1) also known as E-selectin mediate the attachment of leukocytes and have been implicated in the destabilisation of atherosclerotic plaques. Therefore, we hypothesised that plasma selectin levels are associated with adverse clinical outcome. We prospectively studied 855 patients with sonographically confirmed carotid atherosclerosis. During a median follow-up of 6.2 years, corresponding to 5,551 overall person-years, 275 patients (26 %) died. We detected a significant association between cardiovascular mortality and ICAM-1 (adjusted hazard ratio [HR]: 3.43, 95 % confidence interval [CI] 2.00-5.88, p< 0.001) as well as VCAM-1 (adjusted HR: 2.51, 95 %CI 1.45-4.34, p=0.001) when comparing the fourth with the first quartile. Comparable results were obtained for all-cause mortality. In contrast, we could not detect a significant association between E-selectin and all-cause or cardiovascular mortality. We identified the selectins ICAM-1 and VCAM-1 as strong and independent predictors of all-cause and cardiovascular mortality in patients with stable carotid atherosclerosis. These molecules are elevated in states of endothelial activation and might assist to monitor anti-atherosclerotic therapy and select those patients with carotid atherosclerosis, who are at higher risk for cardiovascular events.

The impact of uric acid on long-term mortality in patients with asymptomatic carotid atherosclerotic disease.

BACKGROUND: Serum uric acid (SUA) has been discussed to be related to cardiovascular (CV) disease and outcome. We investigated whether levels of SUA predict long-term mortality in neurologically asymptomatic patients with carotid atherosclerotic disease. METHODS: We prospectively studied 959 consecutive patients with carotid atherosclerosis as evaluated by duplex Doppler sonography for all-cause and CV death, respectively. RESULTS: During a median follow-up time of 6.3 years (interquartile range [IQR], 5.4-7.1 years), 246 deaths (25.7%), including 160 CV deaths (16.7%), were recorded. Median baseline SUA levels were 5.9 mg/dL (IQR, 5.0-7.0 mg/dL). SUA was significantly associated with all-cause death and CV death. Adjusted hazard ratios (HRs) for an increase of 1 mg/dL of SUA levels were 1.12 (95% confidence interval [CI], 1.04-1.21; P = .003) and 1.20 (95% CI, 1.11-1.30; P < .001) for all-cause and CV death, respectively. Quartiles of SUA levels showed a significant association with CV mortality (log-rank P = .002). For CV death, adjusted HRs for quartiles of increasing SUA levels were 1.45 (95% CI, .87-2.43), 1.44 (95% CI, .85-2.46), and 2.26 (95% CI, 1.36-3.76; P < .01), compared with the lowest quartile, respectively. Patients with baseline carotid stenosis of more than 50% and/or increased levels of SUA (≥median) had an approximately 2-fold increase in risk of (CV) death, compared with patients with carotid narrowing of less than 50% and/or SUA levels less than the median (P < .001). CONCLUSIONS: Levels of SUA represent independent predictors for CV mortality in a cohort of patients with asymptomatic carotid atherosclerosis.

Dark chocolate and vascular function in patients with peripheral artery disease: a randomized, controlled cross-over trial.

Flavonoid-rich dark chocolate has positive effects on vascular function in healthy subjects and in patients at risk of atherosclerosis. The impact of dark chocolate on endothelial and microvascular function in patients with symptomatic peripheral artery disease (PAD) has not been investigated so far. In an investigator blinded, randomized, controlled, cross-over trial we assessed the effect of flavonoid-rich dark chocolate and cocoa-free control chocolate on flow-mediated dilatation (FMD) of the brachial artery and on microvascular function (assessed by Laser Doppler fluxmetry) in 21 patients with symptomatic (Fontaine stage II) PAD. Measurements were done in each patient on 2 single days, with an interval of 7 days, at baseline and at 2 hours after ingestion of 50 g dark chocolate or 50 g white chocolate, respectively. FMD remained unchanged after intake of dark chocolate (baseline and 2 hours after ingestion, %: 5.1 [IQR 4.4 to 7.3] and 5.5 [IQR 3.9 to 10.4]; p = 0.57, and after intake of white chocolate (baseline and 2 hours after ingestion, %: 6.4 [IQR 4.5 to 11.4] and 4.4 [IQR 2.6 to 8.7]; p = 0.14. Similarly, microcirculatory parameters were not significantly altered after intake of any chocolate compared with the respective baseline values. In conclusion, a single consumption of 50 g dark chocolate has no effect on endothelial and microvascular function in patients with symptomatic PAD.

Mean platelet volume predicts outcome in patients with asymptomatic carotid artery disease.

BACKGROUND AND OBJECTIVE: Platelets play a pivotal role in atherothrombosis and are potentially involved in the pathogenesis of atherosclerosis. We investigated whether mean platelet volume (MPV) predicts clinical outcome and progression of atherosclerosis in patients with asymptomatic carotid artery disease. METHODS: We studied 1006 of 1268 prospectively collected consecutive patients with asymptomatic carotid atherosclerosis who were evaluated by duplex sonography. Patients were followed up clinically for the occurrence of a major adverse cardiovascular event (MACE), a composite of myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft, stroke and death. RESULTS: During a median follow-up of 3.1 years (interquartile range, 2.5-3.5), a total of 316 (31.5%) MACEs were recorded. Increased levels of MPV were significantly associated with increased risk of the occurrence of MACEs (adjusted hazard ratio [HR] for an increase in one standard deviation [SD] of MPV 1.22, confidence interval [CI] 1.05-1.35, P < 0.01). Patients with MPV levels above 11.8 femtolitre (= fifth quintile) had a significantly higher event rate (41.3% vs. 29.3%, P < 0.001) with an adjusted HR for MACEs of 1.65 (95% CI 1.26-2.16, P < 0.001) compared with patients with MPV levels in the first to fourth quintile. No significant association was found between baseline MPV levels with either baseline degree or progression during a 6-month follow-up of carotid stenosis. CONCLUSION: Mean platelet volume was independently and significantly associated with adverse cardiovascular outcome in patients with asymptomatic carotid atherosclerosis.

Prognostic value of neutrophils in patients with asymptomatic carotid artery disease.

BACKGROUND: Inflammation is associated with atherosclerotic disease. In this context, it has been shown that an increased neutrophil count is a risk factor for cardiovascular events in patients with coronary and peripheral artery disease. However, the impact of neutrophils on long-term mortality in patients with carotid atherosclerosis is not yet fully understood. METHODS: We prospectively studied 853 of 1268 consecutive patients with neurologically asymptomatic carotid stenosis for all-cause and cardiovascular death, respectively. RESULTS: During a median follow-up time of 6.3 years (IQR 5.8-6.7 years) a total of 203 deaths (23.8%), including 134 cardiovascular deaths (15.7%), were recorded. An increase of 1 G/L of neutrophil count indicated an increased risk for all-cause mortality of 1.20 (CI [95%] 1.10-1.31, P < 0.001) and of cardiovascular death of 1.30 (CI 1.17-1.45, P < 0.001), respectively. For the second to the fourth quartile of the neutrophil count, adjusted hazard ratios for all-cause mortality were 1.12 (CI, 0.71-1.75), 1.46 (CI, 0.96-2.21), and 1.76 (CI, 1.15-2.69; P = 0.03 for trend); and 1.41 (CI, 0.80-2.49), 1.53 (CI, 0.88-2.68), and 2.54 (CI, 1.49-4.33; P < 0.01 for trend) for cardiovascular mortality, compared to the lowest quartile, respectively. Patients with baseline carotid stenosis of more than 50% and/or increased neutrophil count (≥median), had a 1.9-2.4 fold increase in risk of (CV-) death, compared to patients with carotid narrowing of less than 50% and/or neutrophil count less than the median (P < 0.001). After adjusting for cardiovascular risk factors, only neutrophils, but not eosinophils, basophils, monocytes, lymphocytes, or the total leukocyte count showed a significant association with long-term mortality. No significant association was found between white blood cell subtypes with either baseline degree or progression during a 6 month follow-up of carotid stenosis. CONCLUSION: The baseline neutrophil count was an independent predictor for all-cause and cardiovascular mortality in neurologically asymptomatic patients with carotid stenosis. Thus, the measurement of neutrophils could provide prognostic information on outcome in patients at risk.

Solid phase detection of C4d-fixing HLA antibodies to predict rejection in high immunological risk kidney transplant recipients.

Protocols for recipient desensitization may allow for successful kidney transplantation across major immunological barriers. Desensitized recipients, however, still face a considerable risk of antibody-mediated rejection (AMR), which underscores the need for risk stratification tools to individually tailor treatment. Here, we investigated whether solid phase detection of complement-fixing donor-specific antibodies (DSA) has the potential to improve AMR prediction in high-risk transplants. The study included 68 sensitized recipients of deceased donor kidney allografts who underwent peritransplant immunoadsorption for alloantibody depletion (median cytotoxic panel reactivity: 73%; crossmatch conversion: n = 21). Pre and post-transplant sera were subjected to detection of DSA-triggered C4d deposition ([C4d]DSA) applying single-antigen bead (SAB) technology. While standard crossmatch and [IgG]SAB testing failed to predict outcomes in our desensitized patients, detection of preformed [C4d]DSA (n = 44) was tightly associated with C4d-positive AMR [36% vs. 8%, P = 0.01; binary logistic regression: odds ratio: 10.1 (95% confidence interval: 1.6-64.2), P = 0.01]. Moreover, long-term death-censored graft survival tended to be worse among [C4d]DSA-positive recipients (P = 0.07). There were no associations with C4d-negative AMR or cellular rejection. [C4d]DSA detected 6 months post-transplantation were not related to clinical outcomes. Our data suggest that pretransplant SAB-based detection of complement-fixing DSA may be a valuable tool for risk stratification.