Patient characteristics and outcomes of carotid endarterectomy and carotid artery stenting: analysis of the German mandatory national quality assurance registry - 2003 to 2014.

AIM: In Germany, every surgical or endovascular procedure on the extracranial carotid artery is documented in a mandatory quality assurance registry. The purpose of this study is to describe the patient characteristics, the indications for treatment, and the short-term outcomes as well as to analyse the corresponding trends from 2003 to 2014. METHODS: Data on demographics, peri-procedural measures, and outcomes were extracted from the annual quality reports published by the Federal Agency for Quality Assurance and the Institute for Applied Quality Improvement and Research in Health Care. Data were available from 2003 to 2014 for carotid endarterectomy (CEA) and from 2012 to 2014 for carotid artery stenting (CAS). The primary outcome event of this study is any stroke or death until discharge from hospital. Temporal trends of categorical variables were statistically analysed using the Cochran-Armitage test for trend. RESULTS: Between 2003 and 2014, 309,405 CEAs and 18,047 CAS procedures were documented in the database; 68.1% of all patients were male. The mean age of patients treated with CEA increased from 68.9 years in 2003 to 70.9 years in 2014. The proportion of patients with ASA stages III to V increased from 65% to 71% in CEA, whereas it decreased from 44% to 41% in CAS patients. 53.1% of all CEAs were performed for asymptomatic patients (group A), 34.4% for symptomatic patients treated electively (group B), and 11.2% a in a collective group including other indications for CEA or CAS (such as recurrent stenosis, carotid aneurysms, emergency treatment due to stroke-in-evolution). The corresponding data for CAS are 49.3%, 26.1% and 26.3% respectively. In group B, the interval between the neurological index event and CEA decreased from 28 to 8 days (P<0.001). In patients treated with CAS, this interval was 9 days in 2012 (no further data available). On average, 67.1% and 48.2% of surgically treated patients as well as 77.8% and 69.8% of CAS patients were neurologically assessed before and after the procedure, respectively. From 2003 to 2014, CEA procedures were performed more frequently in locoregional anesthesia (10.1% to 29.1%, P<0.001). The same trend was observed for the application of the eversion technique (37.0% to 41.6%, P<0.001), the neurophysiological monitoring (49.8% to 61.8%, P<0.001), and the intra-procedural assessment of the treated artery (44.5% to 69.7%, P<0.001). In contrast, shunting was used less frequently (48.1% to 43.0%, P<0.001). Averagely 95.7% of all endovascular procedures were performed using stent-angioplasty. In 54.2% a protection device was used. Nitinol and bare metal stents were used in 74.1% and 21.4% of cases, respectively. The in-hospital rate of any stroke or death decreased from 2.0% to 1.1% in asymptomatic patients treated with CEA without a contralateral stenosis ≥75% or occlusion, P<0.001). In patients treated with CAS this rate did not increase (1.7% to 1.8%, p=0.909). The corresponding rates in CEA and CAS patients with severe contralateral stenosis or occlusion varied between 1.9%-3.1% and 2.2%-2.6%, respectively. In symptomatic patients (group B) with a stenosis of 50 percent or more, the rate of any stroke or death decreased significantly after CEA from 4.2% to 2.4% (P<0.001) and remained stable after CAS (3.9% to 3.5%, P=0.577). CONCLUSION: This report on 327,452 carotid procedures analysed one of the largest quality registries on CEA and CAS worldwide. Data indicate that treated patients became older and sicker, whereas in contrast, the in-hospital rates of stroke or death are decreasing over time.

FR167653 Ameliorates expression of proinflammatory mediators in human umbilical venous endothelial cells and human monocytes.

p38MAP kinase plays a crucial role in intracellular signal transduction of inflammation. The inhibitor of p38 MAP kinase, FR167653, has been proven to be effective to suppress proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in various animal models. The aim of our study was to investigate p38MAP kinase inhibition by FR167653 on the inflammatory profile of cells involved in vascular injury. HUVEC incubated with FR167653 in concentrations of 0.1 to 20 mumol for 24 hours were stimulated with TNF-alpha (20 ng/mL). Human monocytes were incubated with equal concentrations of FR167653 and stimulated with lipopolysaccharides (LPS; 10 microg/mL). In monocytes, p38 MAP kinase could be inhibited by FR167653 (Western blot). The cytokines IL-6 and IL-8 were dose dependently downregulated by FR167653 (enzyme-linked immunosorbent assay) [ELISA]. These results were confirmed at a transcriptional level by real-time polymerase chain reaction (PCR). Gene expression of IL-6 and IL-8 was dose dependently downregulated. The expression pattern of ICAM-1 and VCAM-1 was not altered by FR167653 (ELISA). In HUVEC, the cytokines IL-6 and IL-8 were dose dependently downregulated by FR167653 (ELISA). These results were confirmed on a transcriptional level by real-time PCR. Gene expression of IL-6 and IL-8 were also dose dependently suppressed by FR167653. In addition FR167653 downregulated the expression of the adhesion molecules ICAM-1 and VCAM-1 (ELISA). FR167653 suppressed the development of a proinflamatory profile of HUVEC and human monocytes after stimulation with TNF-alpha or LPS, respectively. These results indicated anti-inflammatory properties of FR167653 on endothelial and inflammatory cells, which may be therapeutically useful to ameliorate vascular injury.

Apoptotic cell death during accelerated rejection in sensitized rat recipients of cardiac allografts.

Accelerated rejection due to host sensitization to major histocompatibility complex antigens is a critical problem in clinical organ transplantation in patients who have previously received an organ transplant, experienced acute rejection episodes, received blood transfusions, or been pregnant. The precise pathologic mechanisms underlying accelerated rejection have not been characterized. Herein, we describe apoptosis during T- and B-cell-driven accelerated rejection of cardiac allografts in presensitized recipients. In an established accelerated rejection model, Lewis rats were sensitized to skin grafts from Wistar-Furth rats; after 7 days, they received Wistar-Furth hearts. These grafts were rejected within 24 hours posttransplantation compared with 10 days in nonsensitized recipients (acute rejection, n = 5). Apoptosis was observed during accelerated rejection of cardiac allografts but not in naïve recipients of hearts, as demonstrated at DNA laddering and TUNEL (terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling) assay. Apoptosis was discovered as a thus far unknown effector mechanism in accelerated cardiac transplant rejection that accompanies combined cellular and humoral immune alloreactivity. Apoptotic cell death in accelerated rejection and the cascade of upstream and downstream events leading to or resulting from this process should be considered critical steps in the pathogenesis of accelerated rejection.

The influence of antigen-dependent and antigen-independent factors on the development of graft vasculopathy in a fully allogeneic cardiac allograft model in the rat.

Graft vasculopathy (GVP) is one of the major obstacles to long-term graft and patient survival after cardiac transplantation and a major reason for morbidity and mortality. Antigen-dependent and antigen-independent factors play causal roles in the development of GVP. The aim of this study was to evaluate antigen-dependent and -independent factors in the development of GVR in a clinically relevant fully allogeneic rat cardiac model under immunosuppression with cyclosporine (CyA). Lewis rats were challenged with Wistar-Furth cardiac allografts. Acute rejection occurred within 10 days after engraftment (n = 6). Daily SC administration of CyA (2.5 mg/kg body weight, n = 12) led to long-term graft survival (>100 days) but did not prevent GVP (Adams Score: 1.7 +/- 1.9, n = 4). Isografts did not develop GVP. In allografts, the dose modification of CyA to 5 mg or 1.25 mg/kg body weight as well as the prolongation of ischemia from 45 minutes to 4 hours did not increase the development of GVP. In isografts, the prolongation of ischemic time from 45 minutes to 4 hours significantly increased the development of GVP (Adams score, 0.3 +/- 0.8 [n = 7] vs 1.2 +/- 1.9 [n = 6]; P < .05). In this fully allogeneic cardiac allograft model with clinically relevant immunosuppressive therapy, GVP was induced independent of the applied CyA dose. In addition, the prolongation of ischemic time did not increase the development of GVP. Isografts only developed significant GVP with long ischemia times. Therefore, an initial injury, either prolonged ischemia time or an allogeneic immune response, predispressed to the development of GVP.

Deazaadenosine prevents leukozyte evasion during acute cardiac allograft rejection by suppression of adhesion molecule expression.

BACKGROUND: In the initial phase after cardiac transplantation, mononuclear cells infiltrate the graft initiating a relevant impulse for rejection. 3-Deazaadenosin (c3Ado), an analog of adenosine, has demonstrated in vitro anti-inflammatory properties. Furthermore, in vivo studies on arteriosclerosis development and septic myocardial dysfunction c3Ado revealed reduced cellular infiltration. In addition ischemia and reperfusion injury could be diminished in a pulmonary animal model. The aim of our study was to investigate the properties of c3Ado to reduce adhesion molecule expression and cellular infiltration in a fully allogeneic cardiac transplant model. METHODS AND RESULTS: Lewis rats were challenged with Wistar-Furth cardiac allografts. Untreated grafts were rejected within 7 days (group 1). In group 2, animals received 2 x 5 mg c3Ado SC per day. Grafts were harvested on days 1, 3, and 6 after transplantation for further examination (n = 4 per group and time point). Immunohistochemical examination revealed significant reduction of graft-infiltrating MHC II positive cells, T-cell receptor positive cells (R73), as well as ED1-positive monocytes and macrophages (P < .01) at days 3 and 6 after transplantation. Adhesion molecule (ICAM-1, VCAM-1) expression on days 1 and 3 after transplantation was almost completely diminished in c3Ado-treated grafts. CONCLUSION: Thus, c3Ado is able to reduce graft infiltration by preventing leukocyte evasion through the suppression of adhesion molecule expression. This may be a novel strategy to protect transplanted organs from early damage after transplantation and extend organ survival after transplantation.

Beneficial effects of intravenously administered N-3 fatty acids for the prevention of atrial fibrillation after coronary artery bypass surgery: a prospective randomized study.

BACKGROUND: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting operation (CABG). Experimental data have shown antiarrhythmic effects of n-3 polyunsaturated fatty acids (PUFA) on myocardial cells. Orally administered PUFA could significantly reduce the rate of postoperative AF. We assessed the efficacy of PUFA for the prevention of AF after CABG. PUFA were given intravenously to prevent variation in bioavailability. METHODS AND RESULTS: 52 patients were randomized to the interventional group, 50 served as controls. In the control group free fatty acids (100 mg soya oil/kg body weight/day) were infused via perfusion pump, starting on admission to hospital and ending at discharge from intensive care. In the interventional group PUFA were given at a dosage of 100 mg fish oil/kg body weight/day. Primary end point was the postoperative development of AF, documented by surface ECG. Secondary end point was the length of stay in the ICU. The demographic, clinical and surgical characteristics of the patients in the two groups were similar. Postoperative AF occurred in 15 patients (30.6 %) in the control and in 9 (17.3 %) in the PUFA group ( P < 0.05). After CABG, the PUFA patients had to be treated in the ICU for a shorter time than the control patients. No adverse effects were observed. CONCLUSIONS: Perioperative intravenous infusion of PUFA reduces the incidence of AF after CABG and leads to a shorter stay in the ICU and in hospital. Our data suggest that perioperative intravenous infusion of PUFA should be recommended for patients undergoing CABG.

Measurement of myocardial oxygen tension: a valid and sensitive method in the investigation of transmyocardial laser revascularization in an acute ischemia model.

BACKGROUND: The effect of transmyocardial laser revascularization (TMLR) on microperfusion and oxygen supply was studied in an acute ischemia model, using 35 pigs, with 13 serving as controls. METHODS: Measurement of tissue oxygen tension was compared with the semiquantitative measurement of microperfusion using contrast echocardiography and infrared laser Doppler. All methods were used before and after coronary occlusion and after TMLR. Effects were measured in the ischemic area and in two ischemia independent areas. RESULTS: At baseline, oxygen partial pressure was 54.2 +/- 15.7 mmHg and decreased to 2.8 +/- 1.4 mmHg ( P < 0.05) after occlusion. After TMLR, oxygen tension increased to 27.3 +/- 8.5 mmHg ( P < 0.05) in the ischemic area, indicating a significant effect of TMLR on microperfusion and oxygen tension. Changes in regional oxygen tension corresponded to Levovist density changes in contrast echocardiography and changes in microperfusion measured by infrared laser Doppler. CONCLUSIONS: Our data indicate that measurement of tissue oxygen tension is a suitable experimental tool to assess the effect of TMLR on myocardial perfusion, which cannot be discriminated using clinical imaging methods.

Preconditioning with ozone abrogates acute rejection and prolongs cardiac allograft survival in rats.

Acute cardiac allograft rejection remains a major cause of morbidity and mortality after heart transplantation and predisposes for the development of graft vasculopathy. The aim of this study was to investigate the immunomodulatory effect of preconditioning of the donor and recipient with medical ozone (O(3)/O(2)) on acute allograft rejection. Minimizing the initial ischemia-reperfusion injury may result in a reduction of graft vasculopathy and ameliorate long-term outcomes after cardiac transplantation. Lewis rats were challenged with Wistar-Furth cardiac allograft. In donor and recipient animals a medical ozone (O(3)/O(2))-pneumoperitoneum was induced by single (1x) or repetitive (5x) insufflation (concentration: 50 microg/mL, 80 mL/kg body weight) of medical ozone intraperitoneally. Without immunomodulatory therapy (n = 11) cardiac allograft survival was 5.9 +/- 0.9 days. Preconditioning with medical ozone alone (single bolus as well as repetitive administration, n = 7) of the donor and recipient animals prolonged cardiac allograft survival significantly to 7.6 +/- 1.4 days (P < .05), without any adjunctive immunosuppressive therapy. In this pilot study, the intraperitoneal administration of ozone in donor and recipient animals protected from ischemia-reperfusion injury, reduced the immunogenicity of the graft, and prolonged cardiac allograft survival. Further studies are warranted to elucidate the underlying mechanisms and--more important--to investigate the effect on the development of graft vasculopathy, the major obstacle to long-term graft and patient survivals.

Sanglifehrin a blocks key dendritic cell functions in vivo and promotes long-term allograft survival together with low-dose CsA.

Sanglifehrin A (SFA) is a novel compound with unsurpassed cyclophilin-binding affinity, but relatively low direct antilymphocytic activity. Here, we report the capacity of SFA to selectively inhibit key dendritic cell (DC) functions in vivo and to suppress acute and chronic heart allograft rejection. We show that in vivo, SFA profoundly decreases DC receptor-mediated endocytosis and macropinocytosis and DC-T-cell allostimulatory activity. Furthermore, SFA abrogates >90% of IL-12p70 production in vivo while having no significant effect on IL-10 and TNF-alpha production. In a rat vascularized heart transplant model, SFA alone did not prevent graft rejection and rejection occurred within 23 days after low-dose CsA, whereas addition of SFA to low-dose CsA promoted long-term graft survival (median survival time >100 days; p = 0.0007). With respect to chronic rejection, SFA + CsA almost completely prevented graft arteriosclerosis compared to animals treated with CsA alone and controls. We propose that SFA represents a novel class of immunophilin-binding immunosuppressants with high activity against DCs and the development of graft vasculopathy in CsA-treated recipients.

Intrathymic immunomodulation in sensitized rat recipients of cardiac allografts: requirements for allorecognition pathways.

BACKGROUND: Intrathymic injection of alloantigen in the form of donor cells, soluble major histocompatibility complex (MHC) molecules, or MHC allopeptides induces donor-specific tolerance in a variety of acute allograft rejection models. We have previously shown that a single intrathymic injection of donor spleen cells into pre-sensitized rats abrogates accelerated (circa 24-hour) rejection and prolongs the survival of cardiac allografts to about 7 days. The present study was designed to investigate the mechanisms by which intrathymic administration of donor cells modifies the course of accelerated rejection. METHODS: Lewis RT1(1) (LEW) rats sensitized by transplantation with Wistar-Furth RT1(u) (WF) skin grafts received WF cardiac allografts 7 days later-a classic model of accelerated rejection. At the time of skin challenge, however, certain animals received intrathymic cell suspensions (either allogeneic or syngeneic) or donor-derived class I and/or class II MHC peptides. RESULTS: Control animals (sensitized by skin grafts but receiving no other treatment) rejected cardiac allografts within 24 hours. Intrathymic injection of WF splenocytes at the time of skin transplantation abrogated rejection at 24 hours and prolonged cardiac allograft survival to 6.6+/-0.6 days (p<0.001), whereas intrathymic administration of syngeneic (LEW) or allogeneic third party Brown Norway RT1(n) cells was ineffective in this regard. Intrathymic injection of gamma-irradiated donor cells marginally extended cardiac allograft survival to 3.0+/-0.9 days (p< 0.001), but the grafts were still rejected in an accelerated fashion. Intrathymic injection of donor-derived class I and/or class II MHC allopeptides at the same time period also failed to prolong cardiac allograft survival beyond 3 days. In the group receiving unmodified donor cells, elevated immunoglobulin M (IgM) and immunoglobulin G (IgG) allo-antibodies were found at the time of cardiac transplantation; this pattern was not observed with any other treatment. CONCLUSION: The superiority of non-modified donor spleen cells over gamma-irradiated donor cells or donor specific allopeptides in modifying the course of accelerated cardiac rejection suggests that direct allorecognition is the dominant pathway initiating rejection in sensitized transplant recipients. Marked alterations in the antidonor IgM and IgG responses are associated with successful abrogation of accelerated rejection by thymic immunomodulatory mechanisms.

Costimulatory signal blockade in murine relapsing experimental autoimmune encephalomyelitis.

Blockade of the CD28-B7 or CD40L-CD40 T cell costimulatory signals prevents induction of experimental autoimmune encephalomyelitis (EAE). However, the effect of simultaneous blockade of these signals in EAE is unknown. We show that administration of either MR1 (to block CD40L) or CTLA4Ig (to block B7) after immunization or after the first attack protects from EAE. Treatment with a combination of CTLA4Ig and MR1 provides additive protection, and is associated with complete absence of mononuclear cell infiltrates in the central nervous system, and marked suppression of proliferation of primed T cells in the periphery. Selective B7-1 blockade did not protect from EAE. These observations have implications for therapy of autoimmune diseases.

Comparative strategies to induce long-term graft acceptance in fully allogeneic renal versus cardiac allograft models by CD28-B7 T cell costimulatory blockade: role of thymus and spleen.

Blocking CD28-B7 T cell costimulatory activation by the fusion protein CTLA4Ig prevents rejection and induces long-term graft acceptance in various experimental transplant models. There are reported differences in the efficacy of CTLA4Ig in renal and cardiac rodent allograft models, but it is not clear whether these are due to the strain or species differences investigated in the different studies reported. This study investigates the effect of blocking CD28-B7 T cell costimulation with murine CTLA4Ig in rat models of acute renal and cardiac allograft rejection models, using the same complete major histocompatibility complex-incompatible strain combination. A single injection of murine CTLA4Ig 2 d after engraftment was able to induce long-term graft acceptance (> 100 d) in 54% of Lewis rat recipients of Wistar-Furth kidneys. Transferring this protocol into the acute Wistar-Furth to Lewis heart allograft model resulted in a mean graft survival time of 24.7+/-16.9 d, and all grafts were ultimately rejected. Only concomitant injection of donor cells (4 x 10(7) splenocytes) plus a single injection of CTLA4Ig on the day of transplant could induce long-term graft acceptance in 50% of animals. In both the cardiac and renal transplant models, the thymus and spleen were required for induction of tolerance. The maintenance phase of tolerance, however, did not require an intact thymus but did require the presence of a spleen. These data have important clinical applicability because human studies with T cell costimulatory blockade are being planned.

CD28-B7 T cell costimulatory blockade by CTLA4Ig in sensitized rat recipients: induction of transplantation tolerance in association with depressed cell-mediated and humoral immune responses.

We tested the effects of blocking CD28-B7 T cell costimulation by using CTLA4Ig in an established transplantation model in which LBNF1 cardiac allografts are rejected in an accelerated manner (<36 h) by LEW rats presensitized with Brown-Norway skin grafts. Treatment with CTLA4Ig with or without donor alloantigen in the sensitization phase (between skin and cardiac engraftment) minimally delayed accelerated rejection. However, adjunctive infusion of CTLA4Ig and donor alloantigen in the effector phase (after cardiac engraftment) resulted in long term graft survival and donor-specific tolerance in 30 to 50% of the recipients. The mutant form of CTLA4Ig, which blocks B7-1 but not B7-2, was ineffective. The tolerant state was accompanied by reduction of cell-mediated (MLR/CTL) responses and depression of humoral (circulating IgM/IgG allo-Abs) alloreactivity in vivo. Hence, the binding of CD28 on T cells to both CD80 and CD86 ligands represents a crucial initial costimulatory step leading to accelerated graft rejection. CTLA4Ig-mediated early blockade of the CD28 signaling pathway combined with transfusion of donor cells in the perioperative period interrupts sensitization and may produce transplantation tolerance. This regimen inhibits T cell costimulation and activation to provide help to CD8+ cytotoxic T and B cells, perhaps, via CTLA4Ig-induced clonal anergy or deletion.

Inhibition of CD26/dipeptidyl peptidase IV activity in vivo prolongs cardiac allograft survival in rat recipients.

The CD26 antigen, one of the major costimulatory molecules in T cell activation, was shown to possess dipeptidyl peptidase IV (DPP IV) activity. Previously, we demonstrated that immunosuppressed kidney transplant patients exhibit lower DPP IV serum activity as compared with healthy individuals. In the present study, we analyzed the role of CD26/DPP IV in the immune cascade triggered by organ transplantation and leading to acute rejection of cardiac allografts in rat recipients. Transplantation of hearts from (Lewis x Brown Norway)F1 donors into Lewis hosts resulted in an early (24 hr) increase in cellular CD26 expression, followed by a rise in DPP IV serum activity, which peaked at day 6, i.e., before the time of actual graft loss. Specific targeting of DPP IV activity with a novel, low-molecular-weight inhibitor of the diphenyl-phosphonate group (prodipine) abrogated acute rejection and prolonged cardiac allograft survival to 14.0+/-0.9 days (P<0.0001). Prodipine treatment prevented the early peak of cellular CD26 expression and thoroughly suppressed systemic DPP IV activity. The inhibition of DPP IV was associated with severely impaired host cytotoxic T lymphocyte responses in vitro. These results demonstrate the role of CD26/DPP IV in alloantigen-mediated immune regulation in vivo and provide the first direct evidence that CD26/DPP IV plays an important role in the mechanism of allograft rejection. The model of targeting CD26/DPP IV may reveal essential interactions on the level of costimulatory alternate T cell activation pathways, allowing a more subtle approach for more selective immunosuppression in transplant recipients.