The proteasome regulates collagen-induced platelet aggregation via nuclear-factor-kappa-B (NFĸB) activation.

INTRODUCTION: Platelets possess critical hemostatic functions in the system of thrombosis and hemostasis, which can be affected by a multitude of external factors. Previous research has shown that platelets have the capacity to synthesize proteins de novo and more recently a multicatalytic protein complex, the proteasome, has been discovered in platelets. Due to its vital function for cellular integrity, the proteasome has become a therapeutic target for anti-proliferative drug therapies in cancer. Clinically thrombocytopenia is a frequent side-effect, but the aggregatory function of platelets also appears to be affected. Little is known however about underlying regulatory mechanisms and functional aspects of proteasome inhibition on platelets. Our study aims to investigate the role of the proteasome in regulating collagen-induced platelet aggregation and its interaction with NFkB in this context. MATERIAL AND METHODS: Using fluorescence activity assays, platelet aggregometry and immunoblotting, we investigate regulatory interactions of the proteasome and Nuclear-factor-kappa-B (NFkB) in collagen-induced platelet aggregation. RESULTS: We show that collagen induces proteasome activation in platelets and collagen-induced platelet aggregation can be reduced with proteasome inhibition by the specific inhibitor epoxomicin. This effect does not depend on Rho-kinase/ROCK activation or thromboxane release, but rather depends on NFkB activation. Inhibition of the proteasome prevented cleavage of NFκB-inhibitor protein IκBα and decreased NFκB activity after collagen stimulation. Inhibition of the NFκB-pathway in return reduced collagen-induced platelet proteasome activity and cleavage of proteasome substrates. CONCLUSIONS: This work offers novel explanations how the proteasome influences collagen-dependent platelet aggregation by involving non-genomic functions of NFkB.

Five-year outcomes of chronic total occlusion treatment with a biolimus A9-eluting biodegradable polymer stent versus a sirolimus-eluting permanent polymer stent in the LEADERS all-comers trial.

BACKGROUND: Few data are available on long-term follow-up of drug-eluting stents in the treatment of chronic total occlusion (CTO). The LEADERS CTO sub-study compared the long-term results in CTO and non-CTO lesions of a Biolimus A9™-eluting stent (BES) with a sirolimus-eluting stent (SES). METHODS: Among 1,707 patients enrolled in the prospective, multi-center, all-comers LEADERS trial, 81 with CTOs were treated with either a BES (n = 45) or a SES (n = 36). The primary endpoint was the occurrence of major adverse cardiac events (MACE): cardiac death, myocardial infarction (MI) and clinically-indicated target vessel revascularization (TVR). RESULTS: At 5 years, the rate of MACE was numerically higher in the CTO group than in the non-CTO group (29.6% vs. 23.3%; p = 0.173), with a significant increase in the incidence of target lesion revascularization (TLR) (21.0 vs. 12.6; p = 0.033), but no difference in stent thrombosis (ST). Patients with CTO receiving a BES demonstrated a lower incidence of MACE (22.2% vs. 38.9%; p = 0.147) with a significant reduction in TLR compared to patients receiving a SES (11.1% vs. 33.3%, p = 0.0214) with an incidence similar to that observed in the non-CTO group treated with BES (11.6%). Definite ST at 5 years nearly halved in the BES group (4.4% vs. 8.3%, p = 0.478) with no ST in the BES group after the first year (0% vs. 8.3%, p for interaction = 0.009). CONCLUSIONS: The use of a BES showed a reduction in MACE, TVR, TLR, and ST over time in the CTO subset with similar outcome as for non-CTO lesions.

Combined therapy with sitagliptin plus granulocyte-colony stimulating factor in patients with acute myocardial infarction - Long-term results of the SITAGRAMI trial.

BACKGROUND: Autologous progenitor cell therapy comprising granulocyte-colony stimulating factor (G-CSF) for mobilization of bone-marrow derived progenitor cells (BMPCs) into peripheral blood and inhibition of dipeptidylpeptidase-IV by sitagliptin for enhanced myocardial recruitment of circulating BMPCs has been shown to improve survival after acute myocardial infarction (MI) in preclinical studies. In the SITAGRAMI trial we found that during short-term follow-up G-CSF plus sitagliptin (GS) failed to show a beneficial effect on cardiac function and clinical events in patients with acute MI that underwent successful PCI. The objective of the present analysis was to assess the impact of GS versus placebo treatment on long-term clinical outcomes of the SITAGRAMI trial patient population. METHODS: In the randomized, prospective, double-blind, placebo-controlled SITAGRAMI trial, 174 patients with acute MI were assigned to GS or placebo in a 1:1 ratio. The primary outcome for the present long-term analysis was the composite of death, MI or stroke on long-term follow-up. RESULTS: The median [IQR] follow-up duration was 4.50 [3.56-5.95] years. The primary outcome occurred in 12.8% of patients assigned to placebo and 9.2% assigned to GS (HR 0.69, 95% CI 0.28-1.69; p=0.42). The incidence of the combined cardiovascular outcome was 47.7% in the placebo- and 41.4% in the GS-group (HR 0.75, 95% CI 0.48-1.18; p=0.21). Overall, there was no significant difference in MACCE rates between both treatment groups (p=0.41). CONCLUSION: These long-term follow-up data indicate that GS therapy does not improve clinical outcomes of patients with acute MI.

Sitagliptin plus granulocyte colony-stimulating factor in patients suffering from acute myocardial infarction: A double-blind, randomized placebo-controlled trial of efficacy and safety (SITAGRAMI trial).

OBJECTIVE: In animal models, G-CSF based progenitor cell mobilization combined with a DPP4 inhibitor leads to increased homing of bone marrow derived progenitor cells to the injured myocardium via the SDF1/CXCR4 axis resulting in improved ejection fraction and survival after acute myocardial infarction (AMI). RESEARCH DESIGN AND METHODS: After successful revascularization in AMI, 174 patients were randomized 1:1 in a multi-centre, prospective, placebo-controlled, parallel group, double blind, phase III efficacy and safety trial to treatment with G-CSF and Sitagliptin (GS) or placebo. Diabetic and non-diabetic patients were included in our trial. The primary efficacy endpoint hierarchically combined global left and right ventricular ejection fraction changes from baseline to 6 months of follow-up (ΔLVEF, ΔRVEF), as determined by cardiac MRI. RESULTS: At follow-up ΔLVEF as well as ΔRVEF did not differ between the GS and placebo group. Patients in the placebo group had a similar risk for a major adverse cardiac event within 12 months of follow-up as compared to patients under GS. CONCLUSION: Progenitor cell therapy comprising the use of G-CSF and Sitagliptin after successfully revascularized acute myocardial infarction fails to show a beneficial effect on cardiac function and clinical events after 12 months. (EudraCT: 2007-003,941-34; ClinicalTrials.gov: NCT00650143, funding: Heinz-Nixdorf foundation).

Biolimus-eluting stent with biodegradable polymer improves clinical outcomes in patients with acute myocardial infarction.

OBJECTIVE: To investigate clinical outcomes of coronary intervention using a biolimus-eluting stent (BES) compared with a sirolimus-eluting stent (SES) in patients with acute myocardial infarction (AMI) in the Limus Eluted from A Durable versus ERodable Stent (LEADERS) coating trial at the final 5-year follow-up. METHODS: The LEADERS trial is a multicentre all-comer study, where patients (n=1707) were randomised to percutaneous intervention with either BES containing biodegradable polymer or SES containing durable polymer. Out of 1707 patients enrolled in this trial, 573 patients had percutaneous coronary intervention for AMI (BES=280, SES=293) and were included in the current analysis. Patient-oriented composite endpoint (POCE, including all death, all myocardial infarction (MI) and all revascularisations), major adverse cardiac events (MACE, including cardiac death, MI and clinically indicated target vessel revascularisation) and stent thrombosis were assessed at 5-year follow-up. RESULTS: The baseline clinical, angiographic and procedural characteristics were well matched between BES and SES groups. In all patients with AMI, coronary intervention with a BES, compared with SES, significantly reduced POCE (28.9% vs 42.3%; relative risk (RR) 0.61, 95% CI 0.47 to 0.82, p=0.001) at 5-year follow-up. There was also a reduction in MACE rate in the BES group (18.2% vs 25.9%; RR 0.67, 95% CI 0.47 to 0.95, p=0.025); however, there was no difference in cardiac death and stent thrombosis. In patients with ST-elevation MI (STEMI), coronary intervention with BES significantly reduced POCE (24.4% vs 39.3%; RR 0.55, 95% CI 0.36 to 0.85, p=0.006), MACE (12.6% vs 25.0%; RR 0.47, 95% CI 0.26 to 0.83, p=0.008) and cardiac death (3.0% vs 11.4%; RR 0.25, 95% CI 0.08 to 0.75, p=0.007), along with a trend towards reduction in definite stent thrombosis (3.7% vs 8.6%; RR 0.41, 95% CI 0.15 to 1.18, p=0.088), compared with SES. CONCLUSIONS: BES, compared with SES, significantly improved safety and efficacy outcomes in patients with AMI, especially those with STEMI, at 5-year follow-up. TRIAL REGISTRATION NUMBER: NCT 00389220.

Platelet mitochondrial membrane depolarization reflects disease severity in patients with sepsis and correlates with clinical outcome.

INTRODUCTION: Sepsis is still a leading cause of morbidity and mortality, even in modern times, and thrombocytopenia has been closely associated with unfavorable disease outcome. Decreases in mitochondrial membrane potential (depolarization) were found in different tissues during sepsis. Previous work suggests that mitochondrial dysfunction of platelets correlates with clinical disease activity in sepsis. However, platelet mitochondrial membrane potential (Mmp) has not been investigated in a clinical follow-up design and not with regard to disease outcome. METHODS: In this study, platelet mitochondrial membrane depolarization was assessed by means of a fluorescent Mmp-Index with flow cytometry in 26 patients with sepsis compared with control patients. Platelet Mmp-Index on admission was correlated with the clinical disease scores Acute Physiology and Chronic Health Evaluation Score II (APACHE II), Sequential Organ Failure Score (SOFA), and Simplified Acute Physiology Score II (SAPS II). Finally, platelet Mmp-Index on admission and follow-up were compared in the group of sepsis survivors and nonsurvivors. Expression of the prosurvival protein Bcl-xL in platelets was quantified by immunoblotting. RESULTS: Platelet mitochondrial membrane depolarization correlated significantly with the simultaneously assessed clinical disease severity by APACHE II (r = -0.867; P < 0.0001), SOFA (r = -0.857; P <0.0001), and SAPS II score (r = -0.839; P < 0.0001). Patients with severe sepsis showed a significant reduction in platelet Mmp-Index compared with sepsis without organ failure (0.18 (0.12 to 0.25) versus 0.79 (0.49 to 0.85), P < 0.0006) or with the control group (0.18 (0.12 to 0.25) versus 0.89 (0.68 to 1.00), P < 0.0001). Platelet Mmp-Index remained persistently low in sepsis nonsurvivors (0.269 (0.230 to 0.305)), whereas we observed recovery of platelet Mmp-Index in the survivor group (0.9 (0.713 to 1.017)). Furthermore, the level of prosurvival protein Bcl-xL decreased in platelets during severe sepsis. CONCLUSION: In this study, we demonstrated that mitochondrial membrane depolarization in platelets correlates with clinical disease severity in patients with sepsis during the disease course and may be a valuable adjunct parameter to aid in the assessment of disease severity, risk stratification, and clinical outcome.

Myeloperoxidase is not useful for detecting stress inducible myocardial ischemia but may be indicative of the severity of coronary artery disease.

BACKGROUND AND OBJECTIVES: Elevated levels of myeloperoxidase (MPO) have been found in patients in different stages of coronary artery disease (CAD). The aim of this study was to assess whether the MPO liberation is increased by stress inducible myocardial ischemia and could be used to improve the diagnostic accuracy of non-invasive evaluation for myocardial ischemia. SUBJECTS AND METHODS: Seventy-six patients with suspected myocardial ischemia who underwent stress myocardial perfusion scintigraphy (MPS) were enrolled. 59 patients with an acute coronary syndrome (ACS) who received a percutaneous coronary intervention along with 12 healthy volunteers were also included in the study. In every subject the MPO plasma levels were assessed by enzyme linked immunosorbent assay. In patients undergoing MPS, the MPO levels were measured serially before and after the stress testing. RESULTS: Of the 76 patients undergoing MPS, 38 were diagnosed with a stress inducible myocardial ischemia. The patients with a stress induced ischemia had significantly higher basal MPO levels than those without it (32±3 ng/mL vs. 24±4 ng/mL, p=0.03). However, there was no relevant change in the MPO levels after the stress test compared to the baseline. The patients with ACS showed significantly higher MPO levels than the patients undergoing MPS (131±14 ng/mL vs. 28±2 ng/mL, p<0.01) and the healthy subjects (131±14 ng/mL vs. 26±2 ng/mL, p<0.01). CONCLUSION: Since the MPO plasma levels did not increase after the stress MPS, MPO appears not to be a useful biomarker for detecting a stress inducible myocardial ischemia. Yet, the MPO levels correlate with the different stages of CAD and may hold significance as an indicator for its clinical severity.

The amount of dysfunctional but viable myocardium predicts long-term survival in patients with ischemic cardiomyopathy and left ventricular dysfunction.

To evaluate the prognostic significance of combined myocardial perfusion SPECT and [18F]FDG PET viability scanning for the prediction of survival in patients with ischemic cardiomyopathy (iCMP) and left ventricular dysfunction. 244 patients (64.0 ± 10.6 years, 86 % men) with iCMP and LVEF ≤ 45 % underwent SPECT/PET. Percent scar tissue and SPECT/PET-mismatch (%-mismatch) were calculated and correlated with event-free survival according to the type of therapy (medical therapy with/out revascularization) provided after imaging. Death from any cause was defined as the primary endpoint. Early revascularization (ER) was performed in 113/244 (46 %) patients within 32 ± 52 days (26 bypass surgeries and 87 percutaneous coronary interventions). 65 patients died during follow-up for a median of 33 months. Kaplan-Meier analysis showed that those patients with ≥ 5 % mismatch not undergoing ER had significantly higher mortality than did the group with similar mismatch who did receive ER. Cox analysis identified both SPECT/PET-mismatch and the interaction of SPECT/PET-mismatch with ER as independent predictors for death due to all causes. A threshold of ≥ 5 % SPECT/PET-mismatch predicted best which patients with iCMP and LV dysfunction would benefit from ER in terms of long-term survival.

Contrast enhanced transesophageal echocardiography in patients with atrial fibrillation referred to electrical cardioversion improves atrial thrombus detection and may reduce associated thromboembolic events.

AIMS: Transesophageal echocardiography (TEE) is the gold standard for the detection of thrombi in patients with atrial fibrillation (AF) before undergoing early electrical cardioversion (CV). However, TEE generates inconclusive results in a considerable number of patients. This study investigated the influence of contrast enhancement on interpretability of TEE for the detection of left atrial (LA) thrombi compared to conventional TEE and assessed, whether there are differences in the rate of thromboembolic events after electrical cardioversion. METHODS: Of 180 patients with AF (51 females, 65.2±13 years) who were referred to CV, 90 were examined with native imaging and contrast enhancement within the same examination (group 1), and 90 were examined with native TEE alone and served as control (group 2). Cineloops of the multiplane examination of the LA and LA appendage (LAA) were stored digitally before and, in group 1, after intravenous bolus application of a transpulmonary contrast agent. Images of group 1 were assessed offline and the diagnosis of LA thrombi was made semi-quantitatively: 1= thrombus present; 2=inconclusive result; 3=no thrombus. The presence of spontaneous echocontrast (SEC) was registered and flow velocity in the LA appendage (LAA-flow) was measured. All patients in whom CV was performed were followed up for 1 year or until relapse of AF. CV related adverse events were defined as any thromboembolic event within 1 week after CV. RESULTS: No serious adverse events occurred during TEE and contrast enhanced imaging. In group 1 atrial thrombi were diagnosed in 14 (15.6%) during native and in 10 (11.1%) patients during contrast enhanced imaging (p<0.001). Of the 10 patients with thrombi in the contrast TEE group, 7 revealed a decreased LAA-flow (≤0,3m/s) and 8 showed moderate or marked SEC. Uncertain results were significantly more common during native imaging than with contrast enhanced TEE (16 vs. 5 patients, p<0.01). Thrombi could definitely be excluded in 60 (66.7%) during conventional and in 75 patients (83.3%) during contrast enhanced TEE (p<0.01). CV was performed subsequently after exclusion of thrombi and at the discretion of the investigator. In group 1, 74 patients (82.2%) were cardioverted and no patient suffered a CV related complication (p=0.084). In group 2, 76 patients (84.4%) underwent CV, of whom 3 suffered a thromboembolic complication after CV (2 strokes, 1 peripheral embolism). CONCLUSION: In patients with AF planned for CV contrast enhancement renders TEE images more interpretable, facilitates the exclusion of atrial thrombi and may reduce the rate of embolic adverse events.

Diagnostic role of whole-body [18F]-FDG positron emission tomography in patients with symptoms suspicious for malignancy after heart transplantation.

BACKGROUND: Increased rates of malignancies and infections occur in transplant patients under immunosuppression, but the resultant clinical symptoms, and results of physical examination, chest X-ray, abdominal ultrasonography and laboratory findings are frequently difficult to interpret or inconclusive. The aim of the present study was to investigate the usefulness of whole-body [(18)F]-FDG PET for investigation of heart transplant patients suffering from suspicious symptoms, with a previously ambiguous diagnosis. METHODS: Seventeen consecutive patients (8 women; 48 ± 22 years) with non-specific symptoms (lymphadenopathy, fever of unknown origin or recurrent febrile temperatures, weight loss, abdominal pain, night sweating, cough or generally reduced physical condition) were evaluated retrospectively. All patients underwent whole-body [(18)F]-FDG examinations by PET (7 patients) or PET/CT (10 patients) at 8 ± 6 (range 0.1 to 21) years after orthotopic heart transplantation (OHT). During a follow-up of 28 ± 25 months, results of bone marrow biopsies, and histologic and/or microbiologic findings were registered and retrospectively compared with the PET results. RESULTS: PET revealed the cause of non-specific symptoms in 9 of 17 patients; there were 5 cases of lymphoproliferative disease (PTLD), 2 carcinomas and 2 cases of infection. Four patients were rated false positive, 1 patient false negative and 3 patients were correctly rated as negative. Sensitivity, specificity and positive and negative predictive values were 0.90, 0.43, 0.69 and 0.75, respectively, giving an overall diagnostic accuracy of 0.71. CONCLUSIONS: A non-invasive strategy of using whole-body [(18)F]-FDG PET or PET/CT in heart transplant recipients with non-specific unexplained symptoms may offer diagnostic stratification for malignancy and infections with a high sensitivity and modest diagnostic accuracy. These findings require prospective confirmation.

Left ventricular dyssynchrony assessed by gated SPECT phase analysis is an independent predictor of death in patients with advanced coronary artery disease and reduced left ventricular function not undergoing cardiac resynchronization therapy.

PURPOSE: Left ventricular (LV) mechanical dyssynchrony (LVMD) was assessed by gated single-photon emission CT myocardial perfusion imaging (MPI) as an independent predictor of death from any cause in patients with known coronary artery disease (CAD) and reduced LV function. METHODS: Between 2001 and 2010, 135 patients (64 ± 11 years of age, 84 % men) with known CAD, reduced LV ejection fraction (LVEF, 38 ± 15 %) and without an implanted cardiac resynchronization therapy device underwent gated MPI at rest. LV functional evaluation, which included phase analysis, was conducted to identify patients with LVMD. Kaplan-Meier survival curves were calculated for death of any cause during a mean follow-up of 2.0 ± 1.7 years. Uni- and multivariate Cox proportional hazards regression models were calculated to identify independent predictors of death from any cause. RESULTS: Of the 135 patients, 30 (22 %) died during follow-up (18 cardiac deaths and 12 deaths from other causes). Kaplan-Meier curves showed a significantly shorter survival time in the patients with severely reduced LVEF (<30 %, n = 45) or with LVMD (n = 81, log-rank test P <0.005). Cox models identified LVMD, LVEF < 30 % and a total perfusion deficit at rest of ≥ 20 % as independent predictors of death from any cause. While patients with LVEF <30 % in conjunction with LVMD had similar survival times irrespective of whether they had early revascularization or medical therapy, those patients with LVEF ≥ 30% and LVMD who underwent revascularization had significantly longer survival. CONCLUSION: In patients with known CAD and reduced LV function, dyssynchrony of the LV is an independent predictor of death from any cause.

Five-year clinical follow-up after sirolimus-eluting stent implantation for the treatment of coronary in-stent restenosis.

BACKGROUND: Late vessel failure by restenosis or thrombosis is a potential limitation of drug-eluting stent implantation. METHODS: We conducted a prospective 5-year clinical evaluation following implantation of sirolimus-eluting Cypher stents for in-stent restenosis regardless of the patient's symptomatic status. A complete 5-year follow-up is reported for 192 consecutive patients. RESULTS: The cumulative rate of death was 5.2%, of cardiac death was 4.2%, of nonfatal myocardial infarction was 4.2%, of definite stent thrombosis was 1.0%, of probable stent thrombosis was 1.0%, of possible stent thrombosis was 2.1%, of target lesion revascularization was 9.4%, of target vessel revascularization was 13.5%, and of major adverse cardiovascular events (death of all causes, nonfatal myocardial infarction, and repeat revascularization; major adverse cardiovascular event) was 22.9%, respectively. CONCLUSION: These results, of a comparably large series, indicate that the implantation of sirolimus-eluting Cypher stents for the treatment of coronary in-stent restenosis is effective and safe and associated with a stable clinical course in the very long term.

The proton pump inhibitor pantoprazole and its interaction with enteric-coated mycophenolate sodium in transplant recipients.

BACKGROUND: In this prospective study we investigated the impact of the proton pump inhibitor (PPI) pantoprazole on the bioavailability of mycophenolic acid (MPA) after oral administration of enteric-coated mycophenolate sodium (EC-MPS; Myfortic) in heart or lung transplant recipients. Previously we demonstrated that pantoprazole reduces the MPA exposure of mycophenolate mofetil (MMF; CellCept) by 34% in area under the concentration-time curve (AUC). Because gastrointestinal side-effects are common after organ transplantation, we investigated the effect of PPI on MPA levels in patients receiving EC-MPS. METHODS: MPA plasma concentrations and inosine monophosphate dehydrogenase (IMPDH) activity at baseline, 30 minutes and 1, 2, 3 and 4 hours were obtained from 21 patients. These patients were treated with pantoprazole 40 mg once daily and EC-MPS twice daily at a mean dose of 960 mg. Measurements were repeated after pantoprazole withdrawal. RESULTS: MPA concentrations and IMPDH activities did not reveal any significant difference during PPI treatment and after withdrawal. MPA AUC, MPA C(max) (maximal MPA concentration), the time until C(max) was reached (T(max)) and IMPDH activity AUC all showed no significant difference. CONCLUSION: We did not find an influence of pantoprazole on EC-MPS pharmacokinetics such as we did for MMF in our previous investigation. A further prospective, large, cross-over study is planned to support these preliminary results. Given that MPA exposure by AUC correlates with the incidence of acute rejection episodes and transplant vasculopathy, the present findings may have clinical implications.

Sirolimus-eluting stent implantation versus beta-irradiation for the treatment of in-stent restenotic lesions: clinical and ultrasound results from a randomised trial.

AIMS: Recent trials with different designs indicated that drug-eluting stents may be superior to vascular brachytherapy (VBT) for the treatment of in-stent restenosis (ISR). We performed a randomised, double-centre, clinical, quantitative coronary angiographic (QCA) and intravascular ultrasound (IVUS) acute and 3-years comparison of 90Sr/90Y-VBT and sirolimus-eluting stent implantation (SES) for ISR. METHODS AND RESULTS: Ninety-one (91) consecutive patients were included. By QCA, SES led to a higher acute gain (2.08 ± 0.41 mm vs. 1.54 ± 0.70 mm, p < 0.0001), higher postprocedural minimum lumen diameter (2.76 ± 0.39 mm vs. 2.39 ± 0.52 mm; p < 0.0001), lower late lumen loss at follow-up (0.09 ± 0.29 vs. 0.39 ± 0.79 mm, p = 0.042), and a higher net lumen gain of the target lesion (2.05 ± 0.51 vs 1.18 ± 1.08 mm, p < 0.0001). By IVUS, the smaller acute gain following VBT was the result of residual intima hyperplasia, the intima hyperplasia formation following SES was extremely low, and the edge-effect was virtually absent after SES, respectively. At 6-month follow-up, both the angiographic restenosis rate (4.7 vs. 22.7%; p < 0.0001) and target lesion revascularisation rate (2.3 vs. 10.4%; p = 0.025) were lower in SES. Importantly, SES showed a stable clinical course at 3-year follow-up while VBT was associated with a sustained incidence of target vessel failure (11.6 vs. 46.7%; p < 0.0001). CONCLUSIONS: SES for ISR is associated with superior QCA, IVUS and clinical results at 6-month and 3-year of follow-up when compared with VBT.

Late and very late catch-up after 90Sr/90Y beta-irradiation for the treatment of coronary in-stent restenosis.

Since late vessel failure has been speculated as a significant limitation of vascular brachytherapy (VBT), we conducted a prospective clinical evaluation at 6, 12, 24, 36 and 60 months follow-up after irradiation with (90)Sr/(90)Y for in-stent restenosis (ISR) regardless of the patient's symptomatic status. Complete five-year follow-up is reported for 104 consecutive patients. The cumulative rate of death was 13.5% (6 months: 0.96%; 12 months: 2.88%; 24 months: 4.81%; 36 months: 7.69%), of acute myocardial infarction 4.81% (2.88%; 4.81%; 4.81%; 4.81%), of late thrombotic occlusion 4.81% (3.85%; 4.81%; 4.81%; 4.81%), of target lesion revascularization (TLR) 27.9% (8.65%; 12.5%; 17.3%; 21.2%), of target vessel revascularization (TVR) 43.3% (12.5%; 19.2%; 22.1%; 29.8%), and of all major adverse cardiovascular events (MACE) 61.5% (16.3%; 26.9%; 31.7%; 42.3%), respectively. Considered that the annual incidence of TVR after the first year following drug-eluting stenting for in-stent restenosis has been reported as approximately 3% per year, an incidence of 5.8% per year following VBT of our study population clearly indicates a more pronounced, delayed and, even in the fifth year after the index procedure, ongoing restenotic process following beta-irradiation of in-stent restenotic lesions associated with clinically relevant adverse cardiovascular events.

CD34+CD140b+ cells and circulating CXCL12 correlate with the angiographically assessed severity of cardiac allograft vasculopathy.

AIMS: We sought to determine whether circulating vascular progenitor cells, such as endothelial progenitor cells (EPCs) or smooth muscle progenitor cells (SPCs), were associated with the severity of cardiac allograft vasculopathy (CAV). METHODS AND RESULTS: CD34(+)CD140b(+) SPCs and CD34(+)KDR(+) EPCs were measured in the peripheral circulation of 187 adult heart transplant recipients by flow cytometry. Cardiac allograft vasculopathy was quantified by angiography using a CAV-specific scoring system. Cardiac allograft vasculopathy was present in 84 patients (44.7%) and was classified as mild in 59 and severe in 25 cases. Circulating SPCs were more frequently detectable in CAV patients than in patients without CAV. The number of CD34(+)CD140b(+) cells showed a stepwise increase in patients with moderate and severe CAV. Smooth muscle progenitor cell counts were higher in patients with coronary stent implant compared with unstented patients with CAV. In contrast, peripheral CD34(+)KDR(+) EPC counts were not changed in CAV patients. Plasma CXCL12 levels correlated with the degree of CAV and SPC counts. None of the different immunosuppressive drug regimes was related to the SPC count or the CXCL12 levels. A multivariate regression analysis revealed that the SPC count was independently associated with the presence of CAV. CONCLUSION: Circulating SPCs, but not EPCs, and plasma CXCL12 concentrations are elevated in CAV patients, indicating that they play prominent roles in transplant arteriosclerosis.

Angiographic assessment of cardiac allograft vasculopathy: results of a Consensus Conference of the Task Force for Thoracic Organ Transplantation of the German Cardiac Society.

Angiograms of cardiac transplant (HTx) recipients were to be evaluated in a ring experiment and a joint consensus on criteria of angiographic evaluation of coronary arteries of HTx patients was to be reached. Twenty-four coronary angiograms from 11 hospitals were circulated. One hundred eighty-eight blinded evaluations were returned. A joint evaluation by six experienced cardiologists was used as reference standard and a consensus evaluation form was developed. Significant lesions (stenosis 75%, 50% in the left main coronary artery) were diagnosed in 10/23 abnormal coronary angiograms (41.7%). Interventional revascularization was recommended in 8/10 (80%). In 21 coronary angiograms distal pruning was found and in 11/21 (52.4%) cases with distal pruning occlusion of at least one peripheral vessel was detected. The best kappa value (0.7) was found for the presence of at least one clinically significant stenosis. Agreement on the site and grade of local stenosis was much less. Some agreement on remodeling was found in assessing diffuse narrowing in the LCA (kappa=0.371, P<0.001). The kappa value for peripheral obliteration was 0.331 (P=0.001). Angiographic evaluation of cardiac allograft vasculopathy, particularly of diffuse and peripheral disease and remodeling, needs standardization. This should be performed in a downward compatible improvement process.

A sulfaphenazole-sensitive EDHF opposes platelet-endothelium interactions in vitro and in the hamster microcirculation in vivo.

AIMS: A CYP2C9-dependent endothelium-derived hyperpolarizing factor (EDHF) controls blood flow in many microvascular beds of various species by targeting vascular smooth muscle potassium channels. Since platelets express the same channels, we tested whether EDHF hyperpolarizes platelets and exerts an antithrombotic function in vivo. METHODS AND RESULTS: Interaction of injected human platelets with the arteriolar wall (platelet-vessel wall interaction, PVWI) was assessed by intravital microscopy in skin muscle of awake hamsters. To understand the mechanisms of EDHF-induced platelet inhibition, we studied whether cultured human umbilical vein endothelial cells overexpressing CYP2C9-mRNA in vitro released a factor that could hyperpolarize human platelets. Under control conditions, there was no firm adhesion of platelets to the arteriolar wall, but temporary PVWI occurred. Local superfusion of the CYP2C9 inhibitor sulfaphenazole, at doses known to block EDHF-dependent dilations, significantly augmented PVWI, as did inhibition of NO synthase. Inhibition of both factors exerted additive effects on PVWI. Likewise, firm adhesion of a small fraction of platelets was observed. The prothrombotic effects of CYP2C9 inhibition in vivo were reversed by exogenous superfusion with 11,12-epoxyeicosatrienoic acids. Hyperpolarization reduced platelet adhesion to endothelial cells under static conditions in vitro and was dependent on calcium-activated potassium channels. The factor also reduced ADP-induced expression of platelet P-selectin, indicating reduction of platelet activity. CONCLUSION: The arteriolar endothelium in vivo continuously releases a CYP2C9-derived EDHF. This EDHF exerts its effects by hyperpolarization of platelets through activation of K(Ca) channels and reduction of platelet adhesion molecule expression, indicating that hyperpolarization reduces platelet activation. This demonstrates that EDHF is part of the antithrombotic properties of healthy endothelium in vivo.

Intravascular ultrasound radiofrequency analysis of the lesion segment profile in ACS patients.

BACKGROUND: Intravascular ultrasound radiofrequency analysis (IVUS-RF) characterizes plaque components as necrotic core (NC) and dense calcium (DC). The aim of this study was to perform an IVUS-RF derived analysis of the lesion segment profile in acute coronary syndrome (ACS) patients. Therefore, we compared the site of the minimum lumen area--cross sectional area (mla-CSA) with the worst lesion site--CSA (ws-CSA) defined by the maximum NC site. METHODS: We performed IVUS-RF derived plaque composition and plaque-type classification analysis in 48 ACS patients with 48 culprit (CL) and 69 non-culprit lesions (NCL). RESULTS: The plaque dimension of the mla- and ws-CSA was significantly different regarding the lumen area (5.18 +/- 2.09 mm2 vs. 6.72 +/- 2.73 mm2, p = 0.0013) and the vessel area (14.80 +/- 5.86 mm2 vs. 17.15 +/- 4.94 mm2, p = 0.0142). The absolute plaque composition was also significantly different regarding the DC tissue (0.71 +/- 0.57 mm2 vs. 0.98 +/- 0.54 mm2, p = 0.0102) and the NC tissue (1.41 +/- 1.28 mm2 vs. 1.85 +/- 1.37 mm2, p = 0.0469). The plaque-type classification revealed significantly more thin cap fibroatheroma (TCFA) lesions at the ws-CSA compared to the mla-CSA (n = 53/89.8% vs. n = 26/44.1%, p < 0.0001). In the majority of the CL and NCL lesion segments the ws-CSA was located proximal to the mla-CSA compared to the distal location (n = 65/55.6% vs. n = 23/19.7%). CONCLUSIONS: In the majority of the lesion segments in ACS patients the ws-CSA is not identical with the mla-CSA. The ws-CSA compared to mla-CSA presented with significantly more NC and DC tissue resulting in a higher amount of TCFA lesions.