Multicenter comparison of transcatheter aortic valve implantation with the self-expanding ACURATE neo2 versus Evolut PRO transcatheter heart valves.

BACKGROUND: New-generation self-expanding transcatheter aortic heart valves (THV) were designed to overcome technical constraints of their preceding generations. We sought to compare the efficacy and safety of the self-expanding ACURATE neo2 (Neo2) versus Evolut PRO (PRO) devices. METHODS: Seven hundred nine patients undergoing transfemoral transcatheter aortic valve implantation (TAVI) with either Neo2 (n = 496) or PRO (n = 213) were included. Propensity score matching (PSM) was performed to account for differences in baseline characteristics. In-hospital and 30-day clinical outcomes were evaluated according to Valve Academic Research Consortium-3 criteria. RESULTS: Baseline characteristics were comparable between both groups after PSM (Neo2: n = 155, Evolut Pro: n = 155). Technical success rates were high in both groups (Neo2: 94.8% vs PRO: 97.4%; p = 0.239). Need for permanent pacemaker implantation was less frequent with Neo2 compared with PRO (7.5% vs 20.6%; p = 0.002), whereas major vascular complications were more frequent with Neo2 (Neo2: 11.6% vs PRO: 4.5%; p = 0.022). Intended valve performance at discharge was high in both groups without relevant differences among groups (Neo2: 97.4% vs. 95.3%; p = 0.328). CONCLUSIONS: Short-term outcomes after TAVI using latest-generation self-expanding THV were excellent, with overall low rates of adverse events. However, Neo2 was associated with lower pacemaker rates and reduced the prevalence of moderate-severe paravalvular leakage. Transprosthetic gradients after TAVI were higher with Neo2 compared with PRO.

Molecular Imaging of Myocardial Fibroblast Activation in Patients with Advanced Aortic Stenosis Before Transcatheter Aortic Valve Replacement: A Pilot Study.

Using multimodal imaging, we investigated the extent and functional correlates of myocardial fibroblast activation in patients with aortic stenosis (AS) scheduled for transcatheter aortic valve replacement (TAVR). AS may cause myocardial fibrosis, which is associated with disease progression and may limit response to TAVR. Novel radiopharmaceuticals identify upregulation of fibroblast activation protein (FAP) as a cellular substrate of cardiac profibrotic activity. Methods: Twenty-three AS patients underwent 68Ga-FAP inhibitor 46 (68Ga-FAPI) PET, cardiac MRI, and echocardiography within 1-3 d before TAVR. Imaging parameters were correlated and then were integrated with clinical and blood biomarkers. Control cohorts of subjects without a history of cardiac disease and with (n = 5) and without (n = 9) arterial hypertension were compared with matched AS subgroups. Results: Myocardial FAP volume varied significantly among AS subjects (range, 1.54-138 cm3, mean ± SD, 42.2 ± 35.6 cm3) and was significantly higher than in controls with (7.42 ± 8.56 cm3, P = 0.007) and without (2.90 ± 6.67 cm3; P < 0.001) hypertension. FAP volume correlated with N-terminal prohormone of brain natriuretic peptide (r = 0.58, P = 0.005), left ventricular ejection fraction (r = -0.58, P = 0.02), mass (r = 0.47, P = 0.03), and global longitudinal strain (r = 0.55, P = 0.01) but not with cardiac MRI T1 (spin-lattice relaxation time) and extracellular volume (P = not statistically significant). In-hospital improvement in left ventricular ejection fraction after TAVR correlated with pre-TAVR FAP volume (r = 0.440, P = 0.035), N-terminal prohormone of brain natriuretic peptide, and strain but not with other imaging parameters. Conclusion: FAP-targeted PET identifies varying degrees of left ventricular fibroblast activation in TAVR candidates with advanced AS. 68Ga-FAPI signal does not match other imaging parameters, generating the hypothesis that it may become useful as a tool for personalized selection of optimal TAVR candidates.

Acute echocardiographic and electrocardiographic effects of triggered left ventricular pacing.

Cardiac resynchronization therapy (CRT) is an essential pillar in the therapy of heart failure patients with reduced ejection fraction (HFrEF) presenting with broad left bundle branch block (LBBB) or pacemaker dependency. To achieve beneficial effects, CRT requires high bi-ventricular (BiV) pacing rates. Therefore, device-manufacturers designed pacing algorithms which maintain high BiV pacing rates by a left ventricular (LV) pacing stimulus immediately following a right ventricular sensed beat. However, data on clinical impact of these algorithms are sparse. We studied 17 patients implanted with a CRT device providing triggered left ventricular pacing (tLVp) in case of atrioventricular nodal conduction. Assessment of LV dyssynchrony was performed using echocardiographic and electrocardiographic examination while CRT-devices were set to three different settings: 1. Optimized bi-ventricular-stimulation (BiV); 2. Physiological AV nodal conduction (tLVp-off); 3. Physiological AV nodal conduction and tLVp-algorithm turned on (tLVp-on). QRS duration increased when the CRT-device was set to tLVp-off compared to BiV-Stim, while QRS duration was comparable to BiV-Stim with the tLVp-on setting. Echocardiographic analysis revealed higher dyssynchrony during tLVp-off compared to BiV-Stim. TLVp-on did not improve LV dyssynchrony compared to tLVp-off. QRS duration significantly decreased using tLVp-algorithms compared to physiological AV nodal conduction. However, echocardiographic examination could not show functional benefit from tLVp-algorithms, suggesting that these algorithms are inferior to regular biventricular pacing regarding cardiac resynchronization. Therefore, medical treatment and ablation procedures should be preferred, when biventricular pacing rates have to be increased. TLVp-algorithms can be used in addition to these treatment options.

Right Ventricular Function Improves Early After Percutaneous Mitral Valve Repair in Patients Suffering From Severe Mitral Regurgitation.

Background: Percutaneous mitral valve edge-to-edge procedure (PMVR) using the MitraClip® system (Abbot Vascular, CA) is an established therapy for severe mitral regurgitation (MR) in patients judged inoperable or at high surgical risk. Besides determining exercise capacity, right ventricular (RV) function has prognostic value in heart failure and after cardiac surgery. We therefore investigated the impact of PMVR on RV function in patients with severe MR. Methods and Results: Sixty-three patients undergoing PMVR at our department were prospectively enrolled. Transthoracic echocardiography was performed before, early (2-12d) after PMVR and after 3 months, including advanced echocardiographic analyses such as 3D imaging and strain analyses. At baseline, all patients presented with advanced heart failure symptoms. Etiology of MR was more often secondary and, if present, left ventricular (LV) dysfunction was predominantly caused by ischemic cardiomyopathy. PMVR substantially reduced MR to a grade ≤ 2 in most patients. Echocardiographic assessment revealed a largely unchanged LV systolic function early after PMVR, while in contrast RV function substantially improved after PMVR [3D RV EF (%): pre 33.7% [27.4; 39.6], post 40.0% [34.5; 46.0] (p < 0.01 vs. pre), 3 months 42.8% [38.3; 48.1] (p < 0.01 vs. pre); 2D RV GLS (%): pre -12.9% [-14.5; -10.5], post -16.0% [-17.9; -12.6] (p < 0.01 vs. pre), 3 months -17.2% [-21.7; -14.9] (p < 0.01 vs. pre)]. Factors that attenuated RV improvement were larger ventricular volumes, lower LV function, secondary MR, and a higher STS score (all p < 0.05). Conclusion: By using advanced echocardiographic parameters, we discovered an early improvement of RV function after PMVR that is preserved for months, independent from changes in LV function. Improvement of RV function was less pronounced in patients presenting with an advanced stage of heart failure and a higher burden of comorbidities reflected by the STS score.

Echocardiographic Parameters to Predict Atrial Fibrillation in Clinical Routine-The EAHsy-AF Risk Score.

Background: Echocardiographic parameters representing impaired left atrial (LA) function and remodeling are of high value to predict atrial fibrillation (AF). This study aimed to develop a prediction model for AF easily to apply in clinical routine containing echocardiographic parameters associated with LA remodeling and-function. Methods and Results: This monocentric, semi-blinded, controlled analysis included 235 patients to derive a prediction model. This prediction model was tested in a validation cohort encompassing 290 cardiovascular inpatients. The derivation and validation cohort included 54 (23%) and 66 (23%) patients with AF, respectively. Transthoracic echocardiography, comprising parameters indicating left atrial remodeling [septal/lateral total atrial conduction time (s/l PA-TDI)] and left atrial volume indexed to a' (LAVI/a') was performed in each patient. Based on multivariable regressions analysis, four variables were enclosed into the EAHsy (Echocardiography, Age, Hypertension)-AF risk score for AF prediction: Hypertension, Age, LAVI/a' and septal PA-TDI. In the validation cohort discrimination was strong (C-statistic 0.987, 95%CI 0.974-0.991) with an adequately performed calibration. The EAHsy-AF risk score was associated with a more precise prediction of AF in comparison to commonly used AF-scores (CHADS2-, ATLAS-, ARIC-, CHARGE-AF score). Conclusion: The EAHsy-AF-Score containing age, hypertension and echocardiographic parameters of atrial dysfunction and remodeling precisely predicts the incidence of AF in a general population of patients with cardiovascular disease. The EAHsy-AF risk score may enable more selective rhythm monitoring in specific patients at high risk for AF.

Multicenter comparison of latest-generation balloon-expandable versus self-expanding transcatheter heart valves: Ultra versus Evolut.

BACKGROUND: Direct comparisons of latest-generation balloon-expandable versus self-expanding transcatheter heart valves (THV) are scarce. To compare outcomes after transcatheter aortic valve replacement (TAVR) with SAPIEN 3 Ultra (Ultra) versus Evolut R or Pro (Evolut) THVs. METHODS: 1612 consecutive patients undergoing TAVR with either Ultra (n = 616) or Evolut (n = 996) were included. After propensity score matching (PSM), 467 and 205 matched pairs were identified in the entire cohort and with latest-generation THVs, respectively. Outcomes were investigated up to 30 days after TAVR. RESULTS: After PSM, baseline characteristics were comparable in the entire cohort (n = 934). Device success (92.7% vs. 87.6%; p = 0.011) and need for permanent pacemaker implantation (PPI) (15.2% vs. 8.4%; p = 0.002) were higher for Evolut compared with Ultra. Elevated gradients (≥20 mm Hg) were less frequent (1.6% vs. 10.4%; p < 0.001), whereas rates of ≥ moderate paravalvular leakage (PVL II+) were more frequent for Evolut compared with Ultra (3.7% vs. 1.3%; p = 0.019). With latest-generation THVs (n = 410), device success was comparable (93.2% vs. 89.8%; p = 0.216), whereas the need for PPI was higher for Evolut Pro compared with Ultra (15.6% vs. 9.8%; p = 0.075). Elevated gradients were less frequent (0% vs. 8%; p < 0.001), whereas rates of PVL II+ were more frequent for Evolut compared with Ultra (5.4% vs. 1.5%; p = 0.028). CONCLUSIONS: Device success rates were high with both THV platforms with low rates of adverse events up to 30 days after TAVR. Compared with Ultra, Evolut was associated with higher pacemaker rates as well as PVL II+, but with less elevated gradients.

Cardiac Fibroblast Activation in Patients Early After Acute Myocardial Infarction: Integration with MR Tissue Characterization and Subsequent Functional Outcome.

After acute myocardial infarction (AMI), fibroblast activation protein (FAP) upregulation exceeds the infarct region. We sought further insights into the physiologic relevance by correlating FAP-targeted PET with tissue characteristics from cardiac MRI (CMR) and functional outcome. Methods: Thirty-five patients underwent CMR, perfusion SPECT, and 68Ga-FAP inhibitor (FAPI)-46 PET/CT within 11 d after AMI. Infarct size was determined from SPECT by comparison to a reference database. For PET, regional SUVs and isocontour volumes of interest determined the extent of cardiac FAP upregulation (FAP volume). CMR yielded functional parameters, area of injury (late gadolinium enhancement [LGE]) and T1/T2 mapping. Follow-up was available from echocardiography or CMR after 139.5 d (interquartile range, 80.5-188.25 d) (n = 14). Results: The area of FAP upregulation was significantly larger than the SPECT perfusion defect size (58% ± 15% vs. 23% ± 17%, P < 0.001) and infarct area by LGE (28% ± 11%, P < 0.001). FAP volume significantly correlated with CMR parameters at baseline (all P < 0.001): infarct area (r = 0.58), left ventricle (LV) mass (r = 0.69), end-systolic volume (r = 0.62), and end-diastolic volume (r = 0.57). Segmental analysis revealed FAP upregulation in 308 of 496 myocardial segments (62%). Significant LGE was found in only 56% of FAP-positive segments, elevated T1 in 74%, and elevated T2 in 68%. Fourteen percent (44/308) of FAP-positive segments exhibited neither prolonged T1 or T2 nor significant LGE. Of note, FAP volume correlated only weakly with simultaneously measured LV ejection fraction at baseline (r = -0.32, P = 0.07), whereas there was a significant inverse correlation with LV ejection fraction obtained at later follow-up (r = -0.58, P = 0.007). Conclusion: Early after AMI and reperfusion therapy, activation of fibroblasts markedly exceeds the hypoperfused infarct region and involves noninfarcted myocardium. The 68Ga-FAPI PET signal does not match regional myocardial tissue characteristics as defined by CMR but is predictive of the evolution of ventricular dysfunction. FAP-targeted imaging may provide a novel biomarker of LV remodeling that is complementary to existing techniques.

Novel self-expanding ALLEGRA transcatheter aortic valve for native aortic stenosis and degenerated bioprosthesis.

OBJECTIVES: To investigate the safety and efficacy of the ALLEGRA valve in routine use. BACKGROUND: The ALLEGRA aortic valve is a self-expanding transcatheter heart valve (THV) with bovine pericardial tissue and was CE approved in March 2017. Its unique design was developed to provide low prosthesis gradients. METHODS: We analyzed patients receiving an ALLEGRA THV between May 2017 and March 2021 at our center for treatment of aortic valve stenosis or degenerated valve prosthesis. Hemodynamic results and clinical outcome according to the Valve Academic Research Consortium-2 consensus criteria were evaluated at discharge and three months post transcatheter aortic valve replacement (TAVR) procedure. 93 patients with a mean age of 82.5 ± 4.8 years and a median EuroScore II of 4.7 ± 3.4 were treated, 15 of them were valve-in-valve procedures. RESULTS: Implantation was successful in 97.8% (91/93) and VARC-2 defined device success was achieved in 94.6% (88/93). In-hospital all-cause mortality was 2.2% (2/93). Life-threatening bleeding, major vascular complications and strokes were 3.2% (3/93), 2.2% (2/93) and 3.2% (3/93), respectively. Paravalvular leakage was none to trace in 60.4%, mild in 38.5% and moderate in 1.1%. Permanent pacemaker implantation in pacemaker naive patients was necessary in 9.5% (8/84). Mean gradient at discharge was 8.2 ± 4.3 mmHg for all patients; 7.1 ± 2.6 mmHg in patients treated for stenosis of the native aortic valve and 13.8 ± 6.3 mmHg in patients treated valve-in-valve. CONCLUSIONS: The ALLEGRA THV provides excellent hemodynamic results and a good safety profile with a low complication rate.

Expansion of CD10neg neutrophils and CD14+HLA-DRneg/low monocytes driving proinflammatory responses in patients with acute myocardial infarction.

Immature neutrophils and HLA-DRneg/low monocytes expand in cancer, autoimmune diseases and viral infections, but their appearance and immunoregulatory effects on T-cells after acute myocardial infarction (AMI) remain underexplored. We found an expansion of circulating immature CD16+CD66b+CD10neg neutrophils and CD14+HLA-DRneg/low monocytes in AMI patients, correlating with cardiac damage, function and levels of immune-inflammation markers. Immature CD10neg neutrophils expressed high amounts of MMP-9 and S100A9, and displayed resistance to apoptosis. Moreover, we found that increased frequency of CD10neg neutrophils and elevated circulating IFN-γ levels were linked, mainly in patients with expanded CD4+CD28null T-cells. Notably, the expansion of circulating CD4+CD28null T-cells was associated with cytomegalovirus (CMV) seropositivity. Using bioinformatic tools, we identified a tight relationship among the peripheral expansion of immature CD10neg neutrophils, CMV IgG titers, and circulating levels of IFN-γ and IL-12 in patients with AMI. At a mechanistic level, CD10neg neutrophils enhanced IFN-γ production by CD4+ T-cells through a contact-independent mechanism involving IL-12. In vitro experiments also highlighted that HLA-DRneg/low monocytes do not suppress T-cell proliferation but secrete high levels of pro-inflammatory cytokines after differentiation to macrophages and IFN-γ stimulation. Lastly, using a mouse model of AMI, we showed that immature neutrophils (CD11bposLy6GposCD101neg cells) are recruited to the injured myocardium and migrate to mediastinal lymph nodes shortly after reperfusion. In conclusion, immunoregulatory functions of CD10neg neutrophils play a dynamic role in mechanisms linking myeloid cell compartment dysregulation, Th1-type immune responses and inflammation after AMI.

Intermediate CD14++CD16+ monocytes decline after transcatheter aortic valve replacement and correlate with functional capacity and left ventricular systolic function.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is the method of choice for patients with severe aortic valve stenosis, who are ineligible or at high risk for surgery. Though TAVR leads to a significant reduction in mortality, a notable amount of patients are re-hospitalized early after TAVR. Parameters or biomarkers predicting outcome are therefore needed to identify patients who benefit most. Specific monocyte subsets have been associated with cardiovascular diseases and were shown to possess prognostic value. METHODS: Peripheral blood was drawn before and after transfemoral TAVR with the self-expanding CoreValve, Boston Lotus or the balloon-expanding Edwards Sapien prosthesis. Classical (CD14++CD16-), intermediate (CD14++CD16+) and non-classical (CD14+CD16++) monocyte subsets were determined by flow cytometry. Transthoracic echocardiography was performed before, early after as well as 3 months after the TAVR procedure. RESULTS: No significant differences in the absolute monocyte counts were found after TAVR. A significant decline in the intermediate monocyte population was though observed early after TAVR (pre 4.01±0.38%, post 2.803±0.34%, p≤0.05). Creatinine levels stayed stable after TAVR procedure and intermediate monocytes were associated with worse renal function. Monocyte decline was not related to changes in CRP-, noradrenaline, cortisol or aldosterone-levels. The amount of intermediate monocytes correlated with worse cardiac function and predicted the possibility to reach an improvement in NYHA functional class at 3 months after TAVR. CONCLUSIONS: A significant decline of intermediate monocytes occurs shortly after TAVR. High levels of intermediate monocytes were associated with worse cardiac function and predicted poor functional capacity, hinting at a possible prognostic value.

Mid-term results of interventional closure of patent foramen ovale with the Occlutech Figulla® Flex II Occluder.

BACKGROUND: Patients with a patent foramen ovale (PFO) who suffered from stroke, TIA or peripheral paradoxical embolism are at substantial risk for recurrent neurologic events and in need for secondary prevention. Interventional closure of PFO has been performed for over 20 years. Numerous devices have been developed and used for treatment. We investigated PFO closure with the third generation Occlutech Figulla® Flex II Occluder device. METHODS: Between 2012 and 2015 57 patients (mean age 47.3 ± 1.5 years) who had suffered from a thromboembolic event of unknown cause underwent transcatheter PFO closure with the Occlutech Figulla® Flex II Occluder at our department. 68.4 % of all patients had suffered from cryptogenic stroke, while TIA had occurred in 28.1 %. Almost all patients were diagnosed with an atrial septum aneurysm (90.9 %) and a severe right-to-left shunt grade 3: >20 microbubbles (92.0 %). Follow-up was done 6 months post intervention by clinical examination and transesophageal contrast echocardiography. RESULTS: No major periprocedural or in-hospital complication occurred. Closure was sufficient with no residual right-to-left shunt in 94.4 % of all patients at 6 months post implantation and only minimal residual shunt in three cases. There were no thrombotic formations associated to the occluder device. Atrial fibrillation occurred in one patient and a recurrent cerebral ischemic event was seen in one patient, who suffered from another TIA. CONCLUSIONS: The Occlutech Figulla® Flex II Occluder device and its delivery system is safe and provides sufficient closure of PFO in patients who suffered from cryptogenic stroke, TIA or paradoxical peripheral embolism.

Multidrug resistance associated protein-1 (MRP1) deficiency attenuates endothelial dysfunction in diabetes.

AIM: The multidrug resistance associated protein-1 (MRP1) is the main transporter of oxidized glutathione in endothelial cells, and blockade of MRP1 improves endothelial cell dysfunction induced by reactive oxygen species. We therefore investigated the role of MRP1 in hyperglycemia-induced endothelial dysfunction and ROS production. METHODS AND RESULTS: Diabetes was induced in 12 week old male MRP1(-/-)- or corresponding FVB wild-type (wt) mice by injection of streptozotocin (50mg/kg for 5 days). Eight weeks thereafter acetylcholine-induced endothelium-dependent vasorelaxation was blunted in aortic rings from diabetic wt mice (blood glucose levels >250 mg/dl) compared with nondiabetic animals (Rmax 74 ± 2% vs. 94 ± 2%, p<0.001). However in aortae from diabetic mice lacking MRP1, endothelium-dependent vasorelaxation was only mildly impaired (Rmax 87 ± 3%, p<0.001 vs. wt). Endothelium-independent relaxation induced by DEA-NONOate was not different among the groups. Streptozotocin-induced diabetes significantly increased aortic superoxide anion and hydrogen peroxide production in wild-type but not in MRP1(-/-) mice. Aortic levels of glutathione were significantly diminished in STZ-treated FVB mice, while preserved in MRP1(-/-) mice. Further, in cultured human aortic endothelial cells, high glucose levels (30 mmol/l) over 5 days significantly increased superoxide production which was inhibited by downregulation of MRP1 via siRNA. CONCLUSIONS: These data indicate that MRP1 plays an important role for endothelial dysfunction and reactive oxygen species production in diabetes and under conditions of hyperglycemia. MRP1 therefore may represent a therapeutic target in treatment of diabetes induced vascular dysfunction.

Pentaerythritol Tetranitrate Targeting Myocardial Reactive Oxygen Species Production Improves Left Ventricular Remodeling and Function in Rats With Ischemic Heart Failure.

Reduced nitric oxide bioavailability contributes to progression of cardiac dysfunction and remodeling in ischemic heart failure. Clinical use of organic nitrates as nitric oxide donors is limited by development of nitrate tolerance and reactive oxygen species formation. We investigated the effects of long-term therapy with pentaerythritol tetranitrate (PETN), an organic nitrate devoid of tolerance, in rats with congestive heart failure after extensive myocardial infarction. Seven days after coronary artery ligation, rats were randomly allocated to treatment with PETN (80 mg/kg BID) or placebo for 9 weeks. Long-term PETN therapy prevented the progressive left ventricular dilatation and improved left ventricular contractile function and relaxation in rats with congestive heart failure. Mitochondrial superoxide anion production was markedly increased in the failing left ventricular myocardium and nearly normalized by PETN treatment. Gene set enrichment analysis revealed that PETN beneficially modulated the dysregulation of mitochondrial genes involved in energy metabolism, paralleled by prevention of uncoupling protein-3, thioredoxin-2, and superoxide dismutase-2 downregulation. Moreover, PETN provided a remarkable protective effect against reactive fibrosis in chronically failing hearts. Mechanistically, induction of heme oxygenase-1 by PETN prevented mitochondrial superoxide generation, NOX4 upregulation, and ensuing formation of extracellular matrix proteins in fibroblasts from failing hearts. In summary, PETN targeting reactive oxygen species generation prevented the changes of mitochondrial antioxidant enzymes and progressive fibrotic remodeling, leading to amelioration of cardiac functional performance. Therefore, PETN might be a promising therapeutic option in the treatment of ischemic heart diseases involving oxidative stress and impairment in nitric oxide bioactivity.

The nitric oxide donor pentaerythritol tetranitrate reduces platelet activation in congestive heart failure.

BACKGROUND: Platelet activation associated with endothelial dysfunction and impaired endogenous platelet inhibition is part of the cardiovascular phenotype of congestive heart failure (CHF) and contributes to the increased risk for thromboembolic complications. Pentaerythritol tetranitrate (PETN) has been shown to release nitric oxide without development of nitrate tolerance. We investigated the effect of chronic PETN treatment on platelet activation and aggregation in an experimental CHF model. METHODS AND RESULTS: Chronic ischemic heart failure was induced in male Wistar rats by coronary artery ligation. Starting 7 days thereafter, rats were randomised to placebo or PETN (80 mg/kg twice daily). After 9 weeks, activation of circulating platelets was determined measuring platelet bound fibrinogen, which requires activated glycoprotein IIb/IIIa on the platelet surface. Binding was quantified by flow-cytometry using a FITC-labelled anti-fibrinogen antibody. Platelet-bound fibrinogen was significantly increased in CHF-Placebo (mean fluorescence intensity: Sham 88±4, CHF-Placebo 104±6, p<0.05) and reduced following treatment with PETN (89±7, p<0.05 vs. CHF-Placebo). Maximal and final ADP-induced aggregation was significantly enhanced in CHF-Placebo vs. Sham-operated animals and normalized / decreased following chronic PETN treatment. Moreover, platelet adhesion was significantly reduced (number of adherent platelets: control: 85.6±5.5, PETN: 40±3.3; p<0.001) and VASP phosphorylation significantly enhanced following in vitro PETN treatment. CONCLUSION: Chronic NO supplementation using PETN reduces platelet activation in CHF rats. Thus, PETN may constitute a useful approach to prevent thromboembolic complications in CHF.

Clopidogrel improves endothelial function and NO bioavailability by sensitizing adenylyl cyclase in rats with congestive heart failure.

Clopidogrel treatment in patients with coronary artery disease not only inhibits platelet activation but also improves endothelial function and nitric oxide (NO) bioavailability. Congestive heart failure (CHF) is associated with endothelial dysfunction and increased platelet activation. In rats with CHF following myocardial infarction (MI), we investigated whether treatment with clopidogrel modifies endothelial function. Eight weeks after coronary artery ligation, rats with CHF were randomized to placebo or the P2Y(12) receptor antagonist clopidogrel (5 mg/kg twice daily, given by gavage) for another 2 weeks. Afterwards, endothelial function was assessed in isolated aortic rings in organ bath experiments. Acetylcholine-induced, endothelium-dependent, nitric oxide-mediated vasorelaxation was significantly attenuated in CHF rats compared to sham-operated animals, and was significantly improved by treatment with clopidogrel. Adenosine-induced vasorelaxation via adenylyl cyclase stimulation was attenuated in CHF and significantly improved by clopidogrel. Increased vasoconstriction to phenylephrine was observed in CHF, particularly evident under cyclooxygenase inhibition, but prevented by clopidogrel treatment. Vasoconstriction by the P2Y(12) activator 2MeS-ADP was increased in CHF. Clopidogrel-treated CHF animals displayed enhanced phosphorylation of AKT and eNOS. In conclusion, clopidogrel improved endothelial function and NO bioavailability in heart failure. During CHF, sensitivity to P2Y(12) signaling was increased leading to impaired adenylyl cyclase-mediated signaling. Chronic P2Y(12)-blockade with clopidogrel improved adenylyl cyclase-mediated signaling including increased AKT- and eNOS-phosphorylation contributing to improved NO-mediated vasorelaxation.