Tricuspid regurgitation velocity and other biomarkers of mortality in children, adolescents and young adults with sickle cell disease in the United States: The PUSH study.

In the US, mortality in sickle cell disease (SCD) increases after age 18-20 years. Biomarkers of mortality risk can identify patients who need intensive follow-up and early or novel interventions. We prospectively enrolled 510 SCD patients aged 3-20 years into an observational study in 2006-2010 and followed 497 patients for a median of 88 months (range 1-105). We hypothesized that elevated pulmonary artery systolic pressure as reflected in tricuspid regurgitation velocity (TRV) would be associated with mortality. Estimated survival to 18 years was 99% and to 25 years, 94%. Causes of death were known in seven of 10 patients: stroke in four (hemorrhagic two, infarctive one, unspecified one), multiorgan failure one, parvovirus B19 infection one, sudden death one. Baseline TRV ≥2.7 m/second (>2 SD above the mean in age-matched and gender-matched non-SCD controls) was observed in 20.0% of patients who died vs 4.6% of those who survived (P = .012 by the log rank test for equality of survival). The baseline variable most strongly associated with an elevated TRV was a high hemolytic rate. Additional biomarkers associated with mortality were ferritin ≥2000 µg/L (observed in 60% of patients who died vs 7.8% of survivors, P < .001), forced expiratory volume in 1 minute to forced vital capacity ratio (FEV1/FVC) <0.80 (71.4% of patients who died vs 18.8% of survivors, P < .001), and neutrophil count ≥10x109 /L (30.0% of patients who died vs 7.9% of survivors, P = .018). In SCD children, adolescents and young adults, steady-state elevations of TRV, ferritin and neutrophils and a low FEV1/FVC ratio may be biomarkers associated with increased risk of death.

Chronic transfusion therapy improves but does not normalize systemic and pulmonary vasculopathy in sickle cell disease.

Tricuspid regurgitant (TR) jet velocity and its relationship to pulmonary hypertension has been controversial in sickle cell disease (SCD). Plasma free hemoglobin is elevated in SCD patients and acutely impairs systemic vascular reactivity. We postulated that plasma free hemoglobin would be negatively associated with both systemic and pulmonary endothelial function, assessed by flow-mediated dilation (FMD) of the brachial artery and TR jet velocity, respectively. Whole blood viscosity, plasma free hemoglobin, TR jet, and FMD were measured in chronically transfused SCD pre- and posttransfusion (N = 25), in nontransfused SCD (N = 26), and in ethnicity-matched control subjects (N = 10). We found increased TR jet velocity and decreased FMD in nontransfused SCD patients compared with the other 2 groups. TR jet velocity was inversely correlated with FMD. There was a striking nonlinear relationship between plasma free hemoglobin and both TR jet velocity and FMD. A single transfusion in the chronically transfused cohort improved FMD. In our patient sample, TR jet velocity and FMD were most strongly associated with plasma free hemoglobin and transfusion status (transfusions being protective), and thus consistent with the hypothesis that intravascular hemolysis and increased endogenous erythropoiesis damage vascular endothelia.

Troponin I and echocardiography in patients with systemic sclerosis and matched population controls.

OBJECTIVES: Cardiac manifestations in systemic sclerosis (SSc) are associated with poor prognosis. Few studies have investigated cardiac troponins in SSc. We studied the relationships between echocardiographic abnormalities, cardiac biomarkers, and disease manifestations in a population-based cohort of patients with SSc and controls. METHOD: The study comprised 110 patients with SSc and 105 age- and sex-matched population-based controls. We examined ventricular function, heart valves, and estimated pulmonary arterial pressure (ePAP) by echocardiography in all participants. Disease characteristics, manifest ischaemic heart disease (IHD), and measurements of N-terminal prohormone brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin I (hs-cTnI) were tabulated. RESULTS: NT-proBNP and hs-cTnI levels were higher in SSc patients than controls. Both NT-proBNP and hs-cTnI were associated with the presence of echocardiographic abnormalities. Forty-four SSc patients and 23 control subjects had abnormal echocardiograms (p = 0.002). As a group, SSc patients had lower (but normal) left ventricular ejection fraction (LVEF, p = 0.02), more regional hypokinesia (p = 0.02), and more valve regurgitations (p = 0.01) than controls. Thirteen patients and four controls had manifest IHD. Decreased right ventricular (RV) function (n = 7) and elevated ePAP (n = 15) were exclusively detected among SSc patients. CONCLUSIONS: Both NTproBNP and hs-cTnI were associated with echocardiographic abnormalities, which were more prevalent in SSc patients than in controls. Our results thus suggest that hs-cTnI could be a potential cardiac biomarker in SSc. Low RV function and signs of pulmonary hypertension (PH) were uniquely found in the SSc group. SSc patients had more valve regurgitation than controls, an observation that warrants more clinical attention.

Pulmonary Hypertension in Children With ß Thalassemia Major, Are Splenectomy and High-Ferritin Levels Related or Not?

We evaluated the risk of pulmonary hypertension (PH) by measuring the velocity of the tricuspid regurgitation jet velocity (TRV) on echocardiography and the associations among the TRV, ferritin, and history of splenectomy in children with ß thalassemia major (TM). In total, 85 children with TM were examined with continuous Doppler flow. Patients with an abnormal TRV (>2.5 m/s) were grouped into those with a TRV of 2.5 to 2.9 m/s and TRV>2.9 m/s. A TRV of >2.5 m/s was identified in 72; 31 (36%) of these patients had a TRV of >2.9 m/s, suggesting a risk for significant PH. The ferritin concentration was significantly higher in patients with a TRV of >2.9 m/s and showed a positive correlation with a TRV. The TRV was significantly correlated with markers of diastolic function: the tricuspid peak early diastolic wave (E) was higher in patients with a TRV of >2.9 m/s and showed a significant correlation with the TRV (R=0.315). The ratio of the TRV over the velocity-time integral (VTI) at the right ventricular outflow tract (TRV/VTI RVOT), which is correlated with the pulmonary vascular resistance, was higher in patients with a TRV of >2.9 m/s. In total, 27 patients had splenectomy. Splenectomized patients had a higher TRV and splenectomy was correlated with the TRV (R=-0.221). A risk of PH as defined by a TRV of >2.9 m/s was common in our patients with TM. Screening with Doppler flow indices on echocardiography can detect PH in early stages.

Haematological determinants of cardiac involvement in adults with sickle cell disease.

AIMS: Cardiac involvement is common in sickle cell disease (SCD). Studies are needed to establish haematological determinants of this involvement and prognostic markers. The aim of the study was to identify haematological factors associated with cardiac involvement in SCD and their impact on prognosis. METHODS AND RESULTS: This longitudinal observational study was performed on 1780 SCD patients with SS or S-ß(0)-thalassemia referred to our centre. Six hundred fifty-six met our inclusion criteria (availability of a blood-workup and echocardiogram obtained <1 year apart, no heart valve surgery and no current pregnancy). Median age was 31 (interquartile range, 25-40) years, and median haemoglobin (Hb) was 87 (80-95)g/L. Left ventricular (LV) dilation, left atrial dilation, cardiac index (CI) >4 L/min/m(2), LV ejection fraction <55%, and tricuspid regurgitant velocity (TRV) ≥2.5 m/s were found in 35, 78, 23, 8.5, and 17% of patients, respectively. Compared with other patients, those in the fourth quartiles (Q4) of LV end-diastolic dimension index (LVEDDind) and left atrial dimension index (LADind) and those with high CI had significantly lower Hb, % foetal Hb (HbF), and red blood cell (RBC) counts; and significantly higher lactate dehydrogenase, bilirubin, and %dense RBCs. Independent haematologic determinants of Q4 LVEDDind and LADind were low RBC count and %HbF; high %dense RBCs were associated with LADind. Low %HbF and RBC count were associated with high CI. High %dense RBCs or no α-thalassemia gene deletion was associated with greater severity of anaemia and cardiac dilation and with higher CI. During the median follow-up of 48 (32-59) months, 50 (7.6%) patients died. Tricuspid regurgitant velocity ≥ 2.5 m/s was a predictor of mortality. The risk of death increased four-fold when left ventricular ejection fraction <55% was present also (P = 0.0001). CONCLUSION: Cardiac dilation and CI elevation in patients with SCD are associated with haematologic variables reflecting haemolysis, RBC rigidity, and blood viscosity. Tricuspid regurgitant velocity ≥ 2.5 and LV dysfunction (even mild) predict mortality.

Serum apelin as a novel non-invasive marker for subclinical cardiopulmonary complications in children and adolescents with sickle cell disease.

BACKGROUND: Cardiovascular involvement represents a leading cause of mortality and morbidity in sickle cell disease (SCD). Apelin is a peptide involved in the regulation of cardiovascular function. AIM: To determine serum apelin among 40 children and adolescents with SCD compared with 40 healthy controls and assess its relation to markers of hemolysis, iron overload as well as cardiopulmonary complications. METHODS: SCD patients, in steady state and asymptomatic for heart disease, were studied stressing on hydroxyurea/chelation therapy, hematological profile, serum ferritin and apelin levels. Full echocardiographic study including assessment of biventricular systolic function and pulmonary artery pressure was done. RESULTS: Apelin levels were significantly lower in SCD patients compared with controls (P<0.001). Cardiopulmonary complications were encountered in 30% of patients. Apelin was significantly decreased among patients with cardiopulmonary disease (P=0.006) whether those at risk of pulmonary hypertension (P=0.018) or patients with heart disease (P=0.043). Hydroxyurea-treated patients had higher apelin levels than untreated ones (P=0.001). Apelin was negatively correlated to lactate dehydrogenase, indirect bilirubin, serum ferritin, end systolic diameter, tricuspid regurgitant jet velocity, right ventricle systolic pressure, pulmonary vascular resistance and tissue Doppler imaging S wave. Apelin cutoff value of 1650ng/L could significantly detect the presence of cardiopulmonary complications in SCD with 90.9% sensitivity and 72.4% specificity. CONCLUSION: Apelin is a promising marker for screening of SCD patients at risk of cardiopulmonary disease because it is altered during the early subclinical stage of cardiac affection. A combination of apelin and echocardiography provides a reliable method to assess cardiopulmonary affection in young SCD patients.

Pulmonary hypertension in well-transfused thalassemia major patients.

The risk for pulmonary hypertension (PH) in thalassemia major (TM) patients remains controversial. We report echocardiography results from 60 TM patients: we evaluated the association between tricuspid regurgitation velocities (TRV), iron stores, and serologic markers of hemolysis and arginine dysregulation. Patients were enrolled from August 2004 until May 2009. All parameters were inversely weighted by the number of exams. TRV was comparable between sexes and it was uncorrelated with age. At the first exam, TR velocities at the upper limits of normal (2.5-2.7m/s) were observed in 8 patients. An abnormal TRV (2.9m/s) was found in 1 patient. Borderline increases in TRV were associated with a reduced global arginine bioavailability (R=-0.399 P=0.005), increased anemia (hemoglobin: R=-0.219 P=0.0461), cardiac index (R=0.223 P=0.0481), and diastolic dysfunction (E/A: R=0.289 P=0.0088; E/E': R=0.223 P=0.0453), but not hemolysis, iron overload and systolic function evaluated by Magnetic Resonance Imaging, and splenectomy. Well-transfused TM patients have a lower risk for PH than thalassemia intermedia patients. However, they do have vascular stressors that raise their lifetime PH risk to levels higher than for the general population. Consequently, we support recommendations for annual echocardiographic screening and cardiac catheterization for persistent TRV above 3m/s.

Elevated tricuspid regurgitant jet velocity in subgroups of thalassemia patients: insight into pathophysiology and the effect of splenectomy.

A high tricuspid regurgitant jet velocity (TRV) signifies a risk for or established pulmonary hypertension (PH), which is a serious complication in thalassemia patients. The underlying pathophysiology in thalassemia subgroups and potential biomarkers for early detection and monitoring are not well defined, in particular as they relate to spleen removal. To better understand some of these unresolved aspects, we examined 76 thalassemia patients (35 non-transfused), 25 splenectomized non-thalassemia patients (15 with hereditary spherocytosis), and 12 healthy controls. An elevated TRV (>2.5 m/s) was found in 25/76 (33 %) of the patients, confined to non-transfused or those with a late start of transfusions, including patients with hemoglobin H-constant spring, a finding not previously described. These non or late-transfused patients (76 % splenectomized) had significantly increased platelet activation (sCD40L), high platelet count, endothelial activation (endothelin-1), and hemolysis (LDH, plasma-free Hb), while hypercoagulable and inflammatory markers were not significantly increased. The same markers were increased in the seven patients with confirmed PH on cardiac catheterization, suggesting their possible role for screening patients at risk for PH. A combination of hemolysis and absence of spleen is necessary for developing a high TRV, as neither chronic hemolysis in the non-splenectomized thalassemia patients nor splenectomy without hemolysis, in the non-thalassemia patients, resulted in an increase in TRV.

Asymmetric dimethylarginine levels in children with ß-thalassemia and their correlations to tricuspid regurgitant jet velocity.

BACKGROUND: Pulmonary hypertension (PHT) may be the leading cause of death in ß-thalassemia patients; however, its pathophysiologic mechanisms are still unclear. Recent studies indicate that asymmetric dimethylarginine (ADMA) plays a role in the initiation and progression of a variety of diseases, especially the cardiovascular system. The aim of this study is to assess the levels of ADMA in children with ß-thalassemia and their correlations with tricuspid regurgitant jet velocity. PROCEDURES: This study was carried out on 30 children with ß-thalassemia major and 30 healthy children served as a control group. Both groups underwent the following investigations: Blood sampling for CBC, LDH, serum ferritin, reticulocytic count, serum bilirubin, AST, ALT, in addition to plasma levels of ADMA. Doppler echocardiography was done for thalassemic group. Patients with tricuspid regurgitant jet velocity (TRV ≥ 2.5 m/sec) were considered risky for PHT. RESULTS: Plasma ADMA levels were significantly higher in patients with ß-thalassemia than control group with a mean value 0.91 ± 0.14 and 0.62 ± 0.10 µmol/L respectively (P = 0.001). There was a significant positive correlation between plasma ADMA levels and tricuspid regurgitant jet velocity. The prevalence of elevated tricuspid regurgitant jet velocity (TRV ≥ 2.5 m/sec) in patients with thalassemia was 33.3%, with a significant increase of elevated TVR (≥ 2.5 m/sec) in patients with thalassemia with splenectomy than in patients without splenectomy. CONCLUSION: High plasma ADMA levels may be implicated in the pathogenesis of PHT in children with ß-thalassemia.

Longitudinal study of echocardiography-derived tricuspid regurgitant jet velocity in sickle cell disease.

Although echocardiography-derived tricuspid regurgitant jet velocity (TRV) is associated with increased mortality in sickle cell disease (SCD), its rate of increase and predictive markers of its progression are unknown. We evaluated 55 subjects (median age: 38 years, range: 20-65 years) with at least two measurable TRVs, followed for a median of 4·5 years (range: 1·0-10·5 years) in a single-centre, prospective study. Thirty-one subjects (56%) showed an increase in TRV, while 24 subjects (44%) showed no change or a decrease in TRV. A linear mixed effects model indicated an overall rate of increase in the TRV of 0·02 m/s per year (P = 0·023). The model showed that treatment with hydroxycarbamide was associated with an initial TRV that was 0·20 m/s lower than no such treatment (P = 0·033), while treatment with angiotensin converting enzyme inhibitors and angiotensin receptor blockers was associated with an increase in the TRV (P = 0·006). In summary, although some patients have clinically meaningful increases, the overall rate of TRV increase is slow. Treatment with hydroxycarbamide may decrease the progression of TRV. Additional studies are required to determine the optimal frequency of screening echocardiography and the effect of therapeutic interventions on the progression of TRV in SCD.

NT-proBNP as a marker of cardiopulmonary status in sickle cell anaemia in Africa.

N-terminal (NT) pro-brain natriuretic peptide (proBNP) > or =160 ng/l has a 78% positive predictive value for pulmonary hypertension and is associated with increased mortality in US sickle cell disease patients, but the importance in sickle cell disease patients in Africa is not known. In a cross-sectional study at Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria, we studied 133 hydroxycarbamide-naïve Nigerian sickle cell anaemia patients aged 18-52 years at steady-state and 65 healthy controls. Twenty-six percent of patients versus 5% of controls had NT-proBNP > or =160 ng/l (P = 0.0006). By logistic regression among the patients, human immunodeficiency virus seropositivity, higher serum ferritin and lower haemoglobin or higher lactate dehydrogenase independently predicted elevated NT-proBNP. After adjustment for haemoglobin concentration, elevated NT-proBNP concentration was associated with an estimated 7.8-fold increase in the odds of severe functional impairment, defined as an inability to walk more than 300 m in 6 min (95% confidence interval 1.5-32.6; P = 0.005). Similarly, elevated tricuspid regurgitation velocity was associated with an estimated 5.6-fold increase in the odds of functional impairment (95% confidence interval 1.5-21.0; P = 0.011). In conclusion, NT-proBNP elevation is common and is associated with markers of anaemia, inflammation and iron status and with severe functional impairment among sickle cell anaemia patients in Nigeria.

Elevated tricuspid regurgitant jet velocity in children and adolescents with sickle cell disease: association with hemolysis and hemoglobin oxygen desaturation.

BACKGROUND: Elevation of echocardiography-determined tricuspid regurgitant jet velocity predicts high systolic pulmonary artery pressure and early mortality in adults with sickle cell disease. The definition, prevalence and clinical correlates of elevated jet velocity have not been established in pediatric patients. The present study tested the hypotheses that elevated jet velocity affects 10% of pediatric patients, is associated with both hemolysis and hypoxia, and has clinical correlates with acute chest syndrome, stroke, transfusion requirement and abnormal 6-minute walk test results. DESIGN AND METHODS: A prospective multicenter study of 310 patients aged 3-20 years old with sickle cell disease under basal conditions and 54 matched controls was conducted. A hemolytic index was generated by principal component analysis of the levels of lactate dehydrogenase, aspartate aminotransferase and bilirubin and reticulocyte count. RESULTS: Elevated jet velocity (defined as > or =2.60 m/sec based on the mean+/-2 SD in controls) occurred in 32 patients (11.0%) including one child of 3 years old. After adjustment for hemoglobin concentration, systolic blood pressure and left ventricular diastolic function, a 2 SD increase in the hemolytic index was associated with a 4.5-fold increase in the odds of elevated jet velocity (p=0.009) and oxygen saturation < or =98% with a 3.2-fold increase (p=0.028). Two or more episodes of acute chest syndrome had occurred in 28% of children with elevated jet velocity compared to in 13% of other children (p=0.012), more than ten units of blood had been transfused in 39% versus 18% (p=0.017) and stroke had occurred in 19% versus 11% (p=0.2). The distance walked in 6-minute walk tests did not differ significantly, but oxygen saturation declined during the tests in 68% of children with elevated jet velocity compared to in 32% of other children (p=0.0002). CONCLUSIONS: According to a pediatric-specific definition the prevalence of elevated jet velocity in this population of young patients with sickle cell disease was 11%. The study provides evidence for independent associations of elevated jet velocity with hemolysis and oxygen desaturation. Further investigations should address whether elevated jet velocity may indicate future complications and whether early intervention is beneficial.

Tricuspid regurgitation in screening for trisomies 21, 18 and 13 and Turner syndrome at 11+0 to 13+6 weeks of gestation.

OBJECTIVE: To investigate the performance of first-trimester screening for aneuploidies by including assessment of tricuspid blood flow in the combined test of maternal age, fetal nuchal translucency (NT) thickness, fetal heart rate (FHR) and serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein A (PAPP-A). METHOD: Screening by the combined test was performed in singleton pregnancies, including 19 614 with chromosomally normal fetuses or the delivery of a phenotypically normal baby (euploid group), 122 with trisomy 21, 36 with trisomy 18, 20 with trisomy 13 and eight with Turner syndrome. In all cases tricuspid flow was assessed to determine if there was tricuspid regurgitation. We examined the performance of two screening strategies: firstly, assessment of tricuspid flow in all patients and secondly, first-stage screening using the combined test in all patients followed by second-stage assessment of tricuspid flow only in those with an intermediate risk of 1 in 51 to 1 in 1000 after the first stage. RESULTS: Tricuspid regurgitation was observed in 0.9% of the euploid fetuses and 55.7%, 33.3% and 30% of the fetuses with trisomies 21, 18 and 13, respectively, and in 37.5% of those with Turner syndrome. In a screening policy based on maternal age, fetal NT, FHR, serum free beta-hCG and PAPP-A, for a fixed false positive rate of 3% the standardized detection rates were 91% for trisomy 21 and 100% for trisomy 18, trisomy 13 and Turner syndrome. Assessment of tricuspid flow in all pregnancies would increase the detection rate of trisomy 21 to 96%, and the detection rates of trisomy 18, trisomy 13 and Turner syndrome would be 92%, 100% and 100%, respectively. The same detection rates were achieved with the two-stage strategy-in which it was necessary to assess tricuspid flow in only 15% of the total population-at a false positive rate of 2.4%. CONCLUSIONS: Assessment of tricuspid flow improves the performance of first-trimester screening for trisomy 21.

Plasma urotensin II as a marker for severity of rheumatic valve disease.

In developing countries, rheumatic valve disease (RVD) is still prevalent. Management of RVD depends on symptomatology, physical examination and echocardiographic evaluation, all of which, however, might be inadequate. Reliable biomarkers to establish severity of RVD and predict complications would be highly beneficial. Urotensin II is regarded as a cardiovascular autacoid/hormone, and its role in cardiovascular diseases is emerging. We hypothesized urotensin II might have pathophysiological roles in RVD. We investigated 71 patients with RVD (mean age 40 +/- 12 years, 17 female patients) and 25 normal subjects (mean age 40 +/- 7 years, 8 female patients). We assessed their New York Heart Association (NYHA) functional class, RVD severity and pulmonary artery pressure (PAP), and measured plasma urotensin II levels. Mitral regurgitation (r = 0.226, p = 0.02), tricuspid regurgitation (r = 0.238, p = 0.02), PAP (r = 0.320, p = 0.01), and NYHA class (r = 0.213, p = 0.03) correlated positively with urotensin II levels. There was positive correlation between urotensin II levels and severity of mitral regurgitation (r = 0.248, p = 0.01) and tricuspid regurgitation (r = 0.326, p = 0.001). In linear regression analysis, only PAP was predictive of urotensin II (beta = 0.3; p = 0.02). In conclusion, this is the first study showing that plasma urotensin II is elevated in chronic RVD, associated with severe mitral and tricuspid valve regurgitation. Furthermore, urotensin II level is correlated with NYHA functional class, and the increase in PAP is predictive of plasma urotensin II.

Independent prognostic value of echocardiography and N-terminal pro-B-type natriuretic peptide in patients with heart failure.

BACKGROUND: Echocardiographic indices of cardiac structure and function and natriuretic peptide levels are strong predictors of mortality in patients with heart failure. Whether cardiac ultrasound and natriuretic peptides provide independent prognostic information is uncertain. METHODS: Echocardiograms and measurements of N-terminal pro-brain natriuretic peptide (NT-proBNP) were prospectively performed in 211 patients with left ventricular systolic dysfunction who were followed for a median of 4 years. Echocardiographic variables and NT-proBNP were examined as predictors of all-cause mortality in univariable and multivariable proportional hazards models. RESULTS: Participants averaged 57 years old (SD 12 years) and had a mean left ventricular ejection fraction of 32% (SD 11%). A total of 71 patients (34%) died during the follow-up period. N-terminal pro-brain natriuretic peptide was a strong predictor of mortality (P < .001) as were multiple echocardiographic measures. In models that included age and NT-proBNP, with other clinical variables eligible for entry by stepwise selection, significant predictors of death included left ventricular ejection fraction (P = .013) and end-diastolic volume (P < .001), left atrial volume index (P = .005), right atrial volume index (P = .003), and tricuspid regurgitation area (P = .015). In models that also included left ventricular ejection fraction, end-diastolic volume of the left ventricle (P = .019), left atrial volume (P = .026), and right atrial volume (P = .020) remained significant predictors of mortality. CONCLUSIONS: Left ventricular size and function and left atrial and right atrial sizes are significant predictors of all-cause mortality in patients with heart failure, independent of NT-proBNP levels and other clinical variables.

Experimental Study of Right Ventricular Hemodynamics After Tricuspid Valve Replacement Therapies to Treat Tricuspid Regurgitation.

The increased understanding of right heart diseases has led to more aggressive interventions to manage functional tricuspid regurgitation (FTR). In some cases of FTR, prosthetic valve replacement is typically considered when concomitant organic components or significant geometrical distortions are involved in the pathology of the tricuspid valve. However, little is known of the performance of current devices in the right heart circulation. In this study, a novel in vitro mock circulatory system that incorporated a realistic tricuspid valve apparatus in a patient-specific silicon right ventricle (RV) was designed and fabricated. The system was calibrated to emulate severe FTR, enabling the investigation of RV hemodynamics in pre- and post-implantation of tri-leaflet tissue implant and bi-leaflet mechanical implant. 2D particle imaging velocimetry was performed to visualize flow and quantify relevant hemodynamic parameters. While our results showed all prosthetic implants improved cardiac output, these implants also subjected the RV to increased turbulence level. Our study also revealed that the implants did not create the optimal behavior of fluid transfer in the RV as we expected. Among the implants tested, tissue implant created the most dominant vortices, which persisted throughout diastole; its observed strong negative vortex could lead to increase energy expenditure due to undesired fluid direction. In contrast, both native valve and mechanical implant had both weaker vortex formation as well as more significant vortex dissipation. Interestingly, the vortex dissipation of native valve was associated with streamlined flow pattern that tended towards the pulmonary outlet, while the mechanical implant generated more regions of flow stagnation within the RV. These findings heighten the imperative to improve designs of current heart valves to be used in the right circulation.

[Polycythemia vera and D-dimer-negative thromboembolism]. / D-Dimer-negative Thromboembolien bei Polycythaemia vera.

CASE REPORT: A 65-year-old patient with polycythemia vera (PV) was admitted with a painful edema of the right arm lasting for 24 h. The D-dimer assay was negative. By phlebography the patient was diagnosed with a fresh thrombosis of the right subclavian vein. 1 week later she developed a D-dimer-negative symptomatic pulmonary embolism. CONCLUSION: If clinical signs of a thromboembolic event are present, the negative predictive value of the D-dimer assay is not sufficient to abandon further definitive diagnosis. Since thromboembolic events are frequent in PV patients, a prophylactic treatment with low-dose acetylsalicylic acid is recommended.