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.

An optimized flow cytometry protocol for analysis of angiogenic monocytes and endothelial progenitor cells in peripheral blood.

Circulating adult CD34(+)VEGFR2(+) endothelial progenitor cells (EPCs) have been shown to differentiate into endothelial cells, thus contributing to vascular homeostasis. Furthermore, a subset of circulating CD14(+) monocytes coexpresses CD16 together with the angiopoietin receptor Tie2 and has been functionally implicated in tumor angiogenesis. However, clinically applicable protocols for flow cytometric quantification of EPCs and Tie2(+) monocytes in peripheral blood and a consensus on reference values remain elusive. The number of Tie2(+)CD14(+)CD16(mid) angiogenic monocytes and CD34(+)VEGFR2(+)CD45(low/-) EPCs was assessed in the peripheral venous blood of patients with stable coronary artery disease by three-color flow cytometry using specific monoclonal antibodies conjugated to PerCP, PE, PE-Cy7, APC, and APC-Cy7. Scatter multigating with exclusion of dead cells was performed to dissect complex mononuclear cell populations. This analysis was further refined by matching bright fluorochromes (PE-Cy7, PE, APC) with dimly expressed markers (CD34, VEGFR2, Tie2), by automatic compensation for minimizing fluorescence spillover and by using fluorescence-minus-one (FMO) controls to determine positive/negative boundaries. Presuming a Gaussian distribution, we obtained average values (mean +/- SD) of 1.45 +/- 1.29% for Tie2(+)CD14(+)CD16(mid) monocytes (n = 11, range: 0.12-3.64%) and 0.019 +/- 0.013% for CD34(+)VEGFR2(+)CD45(low/-) EPCs (n = 17, range: 0.003-0.042%). The intra- and inter-assay variability was 1.6% and 4.5%, respectively. We have optimized a fast and sensitive assay for the flow cytometric quantification of circulating angiogenic monocytes and EPCs in cardiovascular medicine. This protocol may represent a basis for standardized analysis and monitoring of these cell subsets to define their normal range and prognostic/diagnostic value in clinical use.

Effect of Acute Altitude Exposure on Serum Markers of Platelet Activation.

Background: Platelets are the key factor in primary hemostasis. It has been shown that chronic altitude exposure increases platelets' aggregability. Nevertheless, data about acute effects and the underlying mechanisms are sparse. Methods: Sixteen healthy volunteers were examined in our hospital (519 m alt.) and 30 minutes after arrival in the environmental research station on the Zugspitze Mountain (2656 m alt.). Serum levels of soluble p-selectin were examined to elucidate platelet activation. In addition, serum levels of chromogranin A (CGA) as a measure of adrenergic activation, endothelin 1 (ET-1) representing pulmonary vascular tone and monocyte chemoattractant protein-1 (MCP-1) as a measure of inflammatory response were examined. Results: Acute altitude exposure induced a significant increase of p-selectin (116 ± 4.8 pg/mL vs. 132 ± 6.2 pg/mL; p < 0.01). Whereas MCP-1 was significantly lowered (538 ± 50.6 pg/mL to 470 ± 41.1 pg/mL; p = 0.02) and CGA was not altered significantly (88 ± 47.4 ng/mL vs. 79 ± 44 ng/mL; p = 0.22), ET1 was increased significantly from 0.8 ± 0.07 pg/mL to 1.15 ± 0.09 pg/mL (p < 0.01). Conclusion: Our study could demonstrate relevant platelet activation that was accompanied by a 44% increase of ET-1. This activation might obtain clinical relevance in patients with pre-existing cardiovascular disease as a trigger for acute events.

Impairment of Quality of Life among Patients with Wearable Cardioverter Defibrillator Therapy (LifeVest®): A Preliminary Study.

BACKGROUND: Wearable cardioverter defibrillator (WCD) therapy is feasible and safe in patients as a transient protection against sudden cardiac death (SCD). However, the impact of WCD therapy on quality of life (QoL) has not been studied. METHODS: In our single-centre study, 109 consecutive patients with a prescription of WCD were retrospectively analysed. Quality of life has been assessed by a standardized questionnaire (EQ-5D-3L, modified). Additionally, clinical baseline and follow-up data and recorded arrhythmic episodes were evaluated. RESULTS: Mean WCD therapy time was 56.2 (± 42.4) days, with a daily wear time of 19.7 (± 5) hours. A total of 3441 arrhythmia episodes were detected. Of these, 27 (1%) were adequate but did not require shock therapy. Likewise, no inadequate shock therapy occurred. WCD therapy negatively affected quality of life: 43% of patients reported mental health issues. 37% reported pain or discomfort. Self-care, usual activities, and mobility were restricted in 17%, 48%, and 36%, respectively. 29% were afraid of receiving shock therapy, and 48% suffered from sleep disturbance. However, 64% indicated having felt safe during WCD therapy. Accordingly, average quality of life was rated 70/100 points. CONCLUSION: In our cohort, no SCD was prevented by WCD therapy. In contrast, in this preliminary study quality of life was reduced. Thus, careful recommendation of WCD therapy for high risk patients should be considered.

Effects of peripheral vascular intervention on ischemia-modified albumin.

Ischemia -modified albumin was regarded as an early marker of cardiac ischemia. On the other hand, it has been reported that increased ischemia-modified albumin levels are associated with unstable plaque processes like percutaneous coronary intervention, acute coronary syndrome or myocardial infarction. This prospective study aimed to investigate the role of ischemia-modified albumin in patients with peripheral vascular disease undergoing peripheral vascular intervention, a plaque-altering procedure without evidence of tissue ischemia. Peripheral vascular intervention was performed in 21 consecutive patients (68.2+/-13.3 years) with typical leg claudication and documented peripheral vascular disease. Additionally, 96 consecutive patients (66+/-12.0 years) undergoing routine exercise stress test for the exclusion of functionally relevant coronary artery disease were defined as controls. It was assumed that in the latter patients no unstable plaque-altering processes were present. Blood samples were drawn before, and 30 min and 3 h after, revascularization in the peripheral vascular intervention group, as well as before, and 30 min and 3 h after, maximum stress testing in the control group, respectively. Ischemia-modified albumin levels were analyzed using the albumin cobalt-binding test. In patients undergoing peripheral vascular intervention, ischemia-modified albumin increased from 116.6+/-19.1 U/ml at baseline to 132.0+/-19.3 U/ml 30 min after intervention (+14.4+/-15.7%, P<0.001) and decreased to 123.5+/-17.8 U/ml 3 h later (-5.7+/-10.5%, P<0.001 compared with postintervention, P<0.001 compared with baseline). The control group showed a slight but significant decrease in ischemia-modified albumin from 103.0+/-11.0 to 100.2+/-11.6 U/ml poststress (-2.2+/-11.5%, P<0.05) and returned close to baseline 3 h later (101.8+/-10.3 U/ml, +2.4+/-10.9%, P=NS, compared with poststress and with baseline). For both groups, ischemia-modified albumin showed no correlation with albumin (at baseline P=0.62) and total protein (P=0.67), but significant correlation with creatinine (P=0.04) and C-reactive protein (P=0.02). In addition, ischemia-modified albumin was independent of age, sex, alanine aminotransferase, aspartate aminotransferase, creatine kinase, creatine kinase-MB, cholesterol, and triglycerides. This study showed an increased basal ischemia-modified albumin level in patients with peripheral vascular disease undergoing peripheral vascular intervention. Ischemia-modified albumin levels transiently increased shortly after peripheral vascular intervention, indicating a strong correlation between serum concentration of ischemia-modified albumin and processes associated with acute plaque disruption/rupture.

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.

Mycophenolate acid inhibits endothelial NAD(P)H oxidase activity and superoxide formation by a Rac1-dependent mechanism.

Endothelial dysfunction precedes hypertension and atherosclerosis and predicts cardiac allograft vasculopathy and death in heart transplant recipients. Endothelial overproduction of reactive oxygen species, such as superoxide anions produced by NAD(P)H oxidase, induces endothelial dysfunction. Because immunosuppressive drugs have been associated with increased reactive oxygen species production and endothelial dysfunction, we sought to elucidate the underlying mechanisms. Reactive oxygen species, release of superoxide anions, and NAD(P)H oxidase activity were studied in human umbilical vein endothelial cells and in polymorphonuclear neutrophils. Gp91ds-tat was used to specifically block NAD(P)H oxidase. Transcriptional activation of different subunits of NAD(P)H oxidase was assessed by real-time RT-PCR. Rac1 subunit translocation and activation were studied by membrane fractionation and pull-down assays. Calcineurin inhibitors significantly increased endothelial superoxide anions production because of NAD(P)H oxidase, whereas mycophenolate acid (MPA) blocked it. MPA also attenuated the respiratory burst induced by neutrophil NAD(P)H oxidase. Because transcriptional activation of NAD(P)H oxidase was not affected, but addition of guanosine restored endothelial superoxide anions formation after MPA treatment, we speculate that the inhibitory effect of MPA was mediated by depletion of cellular guanosine triphosphate content. This prevented activation of Rac1 and, thus, of endothelial NAD(P)H oxidase. Because all heart transplant recipients are at risk for cardiac allograft vasculopathy development, these differential effects of immunosuppressants on endothelial oxidative stress should be considered in the choice of immunosuppressive drugs.