Association of circulating transcriptomic profiles with mortality in sickle cell disease.

Sickle cell disease (SCD) complications are associated with increased morbidity and risk of mortality. We sought to identify a circulating transcriptomic profile predictive of these poor outcomes in SCD. Training and testing cohorts consisting of adult patients with SCD were recruited and prospectively followed. A pathway-based signature derived from grouping peripheral blood mononuclear cell transcriptomes distinguished 2 patient clusters with differences in survival in the training cohort. These findings were validated in a testing cohort in which the association between cluster 1 molecular profiling and mortality remained significant in a fully adjusted model. In a third cohort of West African children with SCD, cluster 1 differentiated SCD severity using a published scoring index. Finally, a risk score composed of assigning weights to cluster 1 profiling, along with established clinical risk factors using tricuspid regurgitation velocity, white blood cell count, history of acute chest syndrome, and hemoglobin levels, demonstrated a higher hazard ratio for mortality in both the training and testing cohorts compared with clinical risk factors or cluster 1 data alone. Circulating transcriptomic profiles are a powerful method to risk-stratify severity of disease and poor outcomes in both children and adults, respectively, with SCD and highlight potential associated molecular pathways.

Cardiac manifestations in sickle cell disease varies with patient genotype.

Cardiac involvement is well characterized in sickle cell anaemia (SCA) but cardiac features associated with Haemoglobin SC (HbSC) disease are mostly unknown. We compared 60 patients with HbSC disease (median age 31 years, 25 men) to 60 SCA patients and 60 controls matched for age and gender. Left ventricular ejection fraction (LVEF), left ventricle (LV) mass index (LVMi), cardiac index and peak tricuspid regurgitation velocity (TRV) were measured using echocardiography. LV filling pressures were assessed using the ratio of early diastolic transmitral velocity to tissue velocity (E/e' ratio). The LVMi was higher in both genotypes compared to controls. However, whereas LV hypertrophy was observed only in 3(5%) HbSC patients, this condition was diagnosed in 27(45%) SCA patients (P < 0·0001). While cardiac index and TRV were similar in HbSC compared to controls, SCA patients exhibited elevated cardiac output and TRV. LVEF was similar in the 3 groups. However, both genotypes had a higher E/e' ratio compared to controls. Cardiac involvement in SCA was related to anaemia and haemolysis, while LV diastolic dysfunction and TRV in HbSC disease patients were related to arterial hypertension and overweight comorbidities. In summary, cardiac involvement and its determinants are different in HbSC disease and SCA. Patient's genotype should be considered with regard to the echocardiographic indications and findings.

Surgical experience for prolapse of both atrioventricular valves in a patient with filamin A mutation.

A 21-year-old man underwent mitral valve replacement and tricuspid annuloplasty for severe mitral regurgitation and moderate tricuspid regurgitation. Until the operation, he had been treated for hypermobility type Ehlers-Danlos syndrome. Gene examination revealed a mutation in filamin A gene, which is the gene responsible for X-linked myxomatous valvular dystrophy.

Circulating miRNA in functional tricuspid regurgitation. Unveiling novel links to heart failure: A pilot study.

AIM: Severe functional tricuspid regurgitation (FTR) is associated with high risk of cardiovascular events, particularly heart failure (HF) and mortality. MicroRNAs (miRNAs) have been recently identified as novel biomarkers in different cardiovascular conditions, but no studies have focused on FTR. We sought to (1) to identify and validate circulating miRNAs as regulators of FTR and (2) to test association of miRNA with heart failure and mortality in FTR. METHODS AND RESULTS: Consecutive patients with isolated severe FTR (n = 100) evaluated in the outpatient Heart Valve Clinic and age- and gender-matched subjects with no TR (controls, n = 50) were prospectively recruited. The experimental design included (1) a screening phase to identify candidate miRNA differentially expressed in FTR (n = 8) compared with controls (n = 8) through miRNA array profiling of 192 miRNAs using quantitative reverse transcription PCR arrays [qRT-PCR]) and (2) a validation phase in which candidate miRNAs identified in the initial screening were selected for further validation by qRT-PCR in a prospectively recruited cohort of FTR (n = 92) and controls (n = 42). Bioinformatics analysis was used to predict their potential target genes and functional pathways elicited. A combined endpoint of hospital admission due to heart failure (HF) and all-cause mortality was defined. Initial screening identified 16 differentially expressed miRNAs in FTR compared with controls, subsequently confirmed in the validation phase (n = 16 were excluded due to significant haemolysis). miR-186-5p, miR-30e-5p, and miR-152-3p identified FTR with high predictive value [AUC of 0.93 (0.88-0.97), 0.83 (0.75-0.91) and 0.84 (0.76-0.92), respectively]. During a median follow-up of 20.4 months (IQR 8-35 months), 32% of FTR patients reached the combined endpoint. Patients with low relative expression of miR-15a-5p, miR-92a-3p, miR101-3p, and miR-363-3p, miR-324-3p, and miR-22-3p showed significantly higher rates of events (log-rank test for all P < 0.01). Both miR-15a-5p [hazard ratio: 0.21 (0.06-0.649, P = 0.007) and miR-92a-3p (0.27 (0.09-0.76), P = 0.01] were associated with outcomes after adjusting for age, gender, and New York Heart Association functional class. CONCLUSIONS: Circulating miRNAs are novel diagnostic and prognostic biomarkers in severe FTR. The quantification of miR-186-5p, miR-30e-5p, and miR-152-3p held strong diagnostic value, and the quantification of miR-15a-5p and miR-92a-3p are independently associated with outcomes. The recognition of specific miRNAs offers a novel perspective for TR evaluation.

A novel molecular signature for elevated tricuspid regurgitation velocity in sickle cell disease.

RATIONALE: An increased tricuspid regurgitation jet velocity (TRV > 2.5 m/s) and pulmonary hypertension defined by right heart catheterization both independently confer increased mortality in sickle cell disease (SCD). OBJECTIVES: We explored the usefulness of peripheral blood mononuclear cell-derived gene signatures as biomarkers for an elevated TRV in SCD. METHODS: Twenty-seven patients with SCD underwent echocardiography and peripheral blood mononuclear cell isolation for expression profiling and 112 patients with SCD were genotyped for single-nucleotide polymorphisms. MEASUREMENTS AND MAIN RESULTS: Genome-wide gene and miRNA expression profiles were correlated against TRV, yielding 631 transcripts and 12 miRNAs. Support vector machine analysis identified a 10-gene signature including GALNT13 (encoding polypeptide N-acetylgalactosaminyltransferase 13) that discriminates patients with and without increased TRV with 100% accuracy. This finding was then validated in a cohort of patients with SCD without (n = 10) and with pulmonary hypertension (n = 10, 90% accuracy). Increased TRV-related miRNAs revealed strong in silico binding predictions of miR-301a to GALNT13 corroborated by microarray analyses demonstrating an inverse correlation between their expression. A genetic association study comparing patients with an elevated (n = 49) versus normal (n = 63) TRV revealed five significant single-nucleotide polymorphisms within GALNT13 (P < 0.005), four trans-acting (P < 2.1 × 10(-7)) and one cis-acting (P = 0.6 × 10(-4)) expression quantitative trait locus upstream of the adenosine-A2B receptor gene (ADORA2B). CONCLUSIONS: These studies validate the clinical usefulness of genomic signatures as potential biomarkers and highlight ADORA2B and GALNT13 as potential candidate genes in SCD-associated elevated TRV.

Pulmonary artery pressure and iron deficiency in patients with upregulation of hypoxia sensing due to homozygous VHL(R200W) mutation (Chuvash polycythemia).

BACKGROUND: Patients with Chuvash polycythemia, (homozygosity for the R200W mutation in the von Hippel Lindau gene (VHL)), have elevated levels of hypoxia inducible factors HIF-1 and HIF-2, often become iron-deficient secondary to phlebotomy, and have elevated estimated pulmonary artery pressure by echocardiography. The objectives of this study were to provide a comprehensive echocardiographic assessment of cardiovascular physiology and to identify clinical, hematologic and cardiovascular risk factors for elevation of tricuspid regurgitation velocity in children and adults with Chuvash polycythemia. DESIGN AND METHODS: This cross-sectional observational study of 120 adult and pediatric VHL(R200W) homozygotes and 31 controls at outpatient facilities in Chuvashia, Russian Federation included echocardiography assessment of pulmonary artery pressure (tricuspid regurgitation velocity), cardiac volume, and systolic and diastolic function, as well as hematologic and clinical parameters. We determined the prevalence and risk factors for elevation of tricuspid regurgitation velocity in this population and its relationship to phlebotomy. RESULTS: The age-adjusted mean ± SE tricuspid regurgitation velocity was higher in VHL(R200W) homozygotes than controls with normal VHL alleles (2.5±0.03 vs. 2.3±0.05 m/sec, P=0.005). The age-adjusted left ventricular diastolic diameter (4.8±0.05 vs. 4.5±0.09 cm, P=0.005) and left atrial diameter (3.4±0.04 vs. 3.2±0.08 cm, P=0.011) were also greater in the VHL(R200W) homozygotes, consistent with increased blood volume, but the elevation in tricuspid regurgitation velocity persisted after adjustment for these variables. Among VHL(R200W) homozygotes, phlebotomy therapy was associated with lower serum ferritin concentration, and low ferritin independently predicted higher tricuspid regurgitation velocity (standardized beta=0.29; P=0.009). CONCLUSIONS: Children and adults with Chuvash polycythemia have higher estimated right ventricular systolic pressure, even after adjustment for echocardiography estimates of blood volume. Lower ferritin concentration, which is associated with phlebotomy, independently predicts higher tricuspid regurgitation velocity (www.clinicaltrials.gov identifier NCT00495638).

Progression of cardiac disease in patients with lamin A/C mutations.

AIMS: We aimed to study the progression of cardiac dysfunction in patients with lamin A/C mutations and explore markers of adverse cardiac outcome. METHODS AND RESULTS: We followed consecutive lamin A/C genotype-positive patients divided into tertiles according to age. Patients underwent repeated clinical examinations, electrocardiograms (ECGs), and echocardiograms. We followed left ventricular (LV) and right ventricular (RV) size and function, and the severity atrioventricular-valve regurgitations. Outcome was death, LVAD implant, or cardiac transplantation. We included 101 patients [age 44 (29-54) years, 39% probands, 50% female]. We analysed 576 echocardiograms and 258 ECGs during a follow-up of 4.9 (interquartile range 2.5-8.2) years. The PR-interval increased at young age from 204 ± 73 to 212 ± 69 ms (P < 0.001), LV ejection fraction (LVEF) declined from middle age from 50 ± 12% to 47 ± 13% (P < 0.001), while LV volumes remained unchanged. RV function and tricuspid regurgitation worsened from middle age with accelerating rates. Progression of RV dysfunction [odds ratio (OR) 1.3, 95% confidence interval (CI) (1.03-1.65), P = 0.03] and tricuspid regurgitation [OR 4.9, 95% CI (1.64-14.9), P = 0.004] were associated with outcome when adjusted for age, sex, comorbidities, LVEF, and New York Heart Association functional class. CONCLUSION: In patients with lamin A/C genotype, electrical disease started at young age. From middle age, LV function deteriorated progressively, while LV size remained unchanged. Worsening of RV function and tricuspid regurgitation accelerated in older age and were associated with outcome. Our systematic map on cardiac deterioration may help optimal monitoring and prognostication in lamin A/C disease.

Stress Doppler echocardiography in relatives of patients with idiopathic and familial pulmonary arterial hypertension: results of a multicenter European analysis of pulmonary artery pressure response to exercise and hypoxia.

BACKGROUND: This large, prospective, multicentric study was performed to analyze the distribution of tricuspid regurgitation velocity (TRV) values during exercise and hypoxia in relatives of patients with idiopathic and familial pulmonary arterial hypertension (PAH) and in healthy control subjects. We tested the hypothesis that relatives of idiopathic/familial PAH patients display an enhanced frequency of hypertensive TRV response to stress and that this response is associated with mutations in the bone morphogenetic protein receptor II (BMPR2) gene. METHODS AND RESULTS: TRV was estimated by Doppler echocardiography during supine bicycle exercise in normoxia and during 120 minutes of normobaric hypoxia (FIO(2)=12%; approximately 4500 m) in 291 relatives of 109 PAH patients and in 191 age-matched control subjects. Mean maximal TRVs were significantly higher in PAH relatives during both exercise and hypoxia. During exercise, 10% of control subjects but 31.6% of relatives (P<0.0001) exceeded the 90% quantile of mean maximal TRV seen in control subjects. Hypoxia revealed hypertensive TRV in 26% of relatives (P=0.0029). Among control subjects, TRV at rest was not related to age, sex, body mass index, systemic blood pressure, smoking status, or heart rate. Within kindreds identified as harboring deleterious mutations of the BMPR2 gene, a hypertensive TRV response occurred significantly more often compared with those without detected mutations. CONCLUSIONS: Pulmonary hypertensive response to exercise and hypoxia in idiopathic/familial PAH relatives appears as a genetic trait with familial clustering, being correlated to but not caused by a BMPR2 mutation. The suitability of this trait to predict manifest PAH development should be addressed in long-term follow-up studies.

Neonatal Marfan syndrome: unusually large deletion of exons 24-26 of FBN1 associated with poor prognosis.

Neonatal Marfan syndrome is a very rare subset of the classical Marfan syndrome with pronounced phenotypic expression especially of the cardiovascular manifestations. It is associated with a very poor prognosis, with approximately 50% of affected infants dying from cardiac failure during the first year of life. We present a newborn with the classical phenotype of neonatal Marfan syndrome. Within few hours after birth, progressive and refractory heart failure developed. Postmortal molecular study revealed an unusually large deletion of exons 24-26 within the so-called neonatal region of the gene FBN1, which might explain the unfavourable course of the disease in our patient.

Bromocriptine use and the risk of valvular heart disease.

It has been reported that patients on pergolide and carbergoline have an increased risk of developing valvular heart disease. It is uncertain if bromocriptine, an ergot-derived dopamine agonist (DA) with partial 5-HT(2B) activity, is associated with a similar risk. We assessed the frequency of valvular heart disease in Parkinson's disease (PD) patients on bromocriptine compared to pergolide and a control group of PD patients who had not been treated on any DA. Seventy-two PD patients on bromocriptine, 21 patients on pergolide, and 47 control PD patients were recruited. Transthoracic echocardiographic studies were performed and reviewed by a blinded cardiologist. The risk for the bromocriptine group to develop any abnormal valvular regurgitation was 3.32 (adjusted OR, 95% CI: 1.11-9.92, P = 0.03) compared to controls, whereas the risk for the pergolide group was 3.66 (adjusted OR, 95% CI: 1.22-10.97, P = 0.02). When cumulative dose of bromocriptine was analyzed by quartiles, patients with a greater exposure to bromocriptine had significantly higher risk of developing both mild and moderate-severe regurgitations (P for trend, 0.005 and 0.019, respectively). This study demonstrated that bromocriptine use was associated with an increased risk of developing valvular heart disease, which occurred in a cumulative dose-dependent manner.

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.

Specificity of fetal tricuspid regurgitation in prediction of Down syndrome in Thai fetuses at 17-23 weeks of gestation.

OBJECTIVE: To assess the specificity of tricuspid regurgitation (TR) in prediction of Down syndrome in Thai fetuses at 17-23 weeks' gestation and to determine the prevalence of TR among normal chromosome fetuses in a high-risk population. MATERIAL AND METHOD: A prospective study was performed in 395 high-risk pregnant women who underwent amniocentesis or cordocentesis for fetal karyotyping at 17-23 weeks. The presence or absence of TR was determined by pulsed wave Doppler at the time of prenatal diagnosis. TR was diagnosed when the regurgitation flow was observed for at least half of systole or > or = 70 milliseconds with maximum velocity of > or = 100 cm/sec. The diagnostic values of TR for detection of Down syndrome were calculated. RESULTS: The prevalence of TR was 3.8% (14/370) in normal chromosome fetuses and 40% (2/5) in Down syndrome fetuses. Fetuses with TR had a higher chance to be Down syndrome (11.1%) than those without TR (0.8%) (95% CI of the difference, 0.09-32.9, p = 0.036). Specificity, sensitivity, NPV and PPV of TR in prediction of Down syndrome were 95.9%, 40%, 99.2% and 11.1%, respectively. Among normal chromosome fetuses with TR, 14.3% (2/14) had congenital cardiac abnormalities. CONCLUSION: TR is not only a high specificity secondary ultrasound marker at 17-23 weeks to identify fetuses with Down syndrome in high-risk pregnant women but also associates with the risk of cardiac defects in normal chromosome fetuses.

Is genomic screening necessary for fetuses who suffer moderate to severe tricuspid regurgitation?: A case report.

RATIONALE: Tricuspid regurgitation (TR) is a frequent finding during echocardiography screening in fetal or neonatal life, which reveals a weak association between TR and cardiac malformation. Except for structural abnormalities, dilated cardiomyopathy (DCM) ranks as the top reason for early child morbidity and mortality among all kinds of cardiomyopathy. In the early fetal stage, cardiac abnormalities detected by early fetal genetic testing followed by abnormalities on ultrasound would provide more valuable information for parents and physicians to make a better therapeutic schedule. PATIENT CONCERNS: A case of severe TR was found via the fetal ultrasound screening. After birth, this child suffered severe heart dysfunction, and echocardiography confirmed a DCM phenotype within a very short time. DIAGNOSIS AND INTERVENTION: A 40-year-old female received routine fetal echocardiographic screening, which demonstrated that the fetus presented severe TR. Six months after birth, the baby experienced severe heart failure, as the EF dropped to 22% with an extremely large LV chamber. The genomic sequence had been determined, and 3 pathogenic gene mutations located in 2 genes, cardiac troponin T (TNNT2) c.548G>A, desmoplakin (DSP) c.3146C>T, and DSP c.5213G>A, were identified. Finally, the patient was diagnosed with DCM. This child received digoxin, hydrochlorothiazide, spironolactone diuresis, captopril, and L-carnitine, and the symptoms of heart failure had been controlled as the patient waited for heart transplantation. OUTCOMES: During the follow-up, the patient still suffered from poor heart function and an enlarged left ventricle. Concomitantly, the parents placed her on a waiting list for heart transplantation. LESSONS: Fetal TR is a common phenomenon, and many studies have indicated that isolated TR is not an appropriate predictor of chromosomal abnormalities or congenital heart defects. However, according to this case, it is urgent to recommend that the mother should take advantage of free fetal DNA analysis in a maternal blood sample to obtain further molecular evidence once fetal echocardiography reveals moderate to severe TR with any maternal high-risk factors for birth defects.

De novo 18q deletion with mitral valve insufficiency.

We report an 18-year-old Turkish girl with an 18q- deletion and abnormalities of face, mental and growth retardation, mitral deficiency and hypothyroidism. Mitral deficiency has not been reported in 18q deletion syndrome cases previously. We performed cytogenetic and molecular cytogenetic analysis, and brain MRI. Her karyotype was 46,XX,del(18)(q21.2-->qter). This report compares the symptoms and features of the present patient with previously reported cases with 18q syndrome.

Evaluation of first-trimester tricuspid regurgitation for Down syndrome screening.

Screening for Down syndrome has become an integral part of prenatal care. In recent years, there has been significant interest in first-trimester screening methods. Increased nuchal translucency in the first trimester of pregnancy has been identified as a marker for chromosomal anomalies and congenital cardiac disease. In addition, research has identified a correlation between tricuspid regurgitation, diagnosed by pulsed-wave Doppler ultrasonography, in aneuploid fetuses between 11 and 13 + 6 weeks' gestation. This article provides a brief historical overview of screening for aneuploidy and examines the emerging trend and pitfalls of first-trimester screening.

An uncommon cause of tricuspid regurgitation: three-dimensional echocardiographic incremental value, surgical and genetic insights.

Congenital tricuspid valve disease is a rare defect that includes regurgitation, stenosis and Ebstein's anomaly. We report a case of severe tricuspid regurgitation associated with functional mitral regurgitation in a 47-year-old man with congestive heart failure. Transthoracic echocardiography (TTE) ruled out any Ebstein's anomaly. Three-dimensional TTE revealed a 'tricuspid hole' into the anterior leaflet that was only attached to the tricuspid annulus next to both anteroseptal and anteroposterior commissures. There was no sign of leaflet tear or perforation. The surgical repair of the tricuspid and mitral valves was performed with an optimal result. No sign of endocarditis or rheumatic disease was observed during the intervention. Sequence analysis of GATA4, HEY2 and ZFPM2 genes was performed, but no causative mutation was identified.

Influence of angiotensin-converting enzyme gene insertion/deletion polymorphism on rheumatic valve involvement, valve severity and subsequent valve calcification.

BACKGROUND AND AIM OF THE STUDY: The relationship between the severity of chronic rheumatic heart disease (RHD) and predisposing factors is unknown, and genetic predictors for severe scarring and calcification of the mitral valve are not well defined. A high angiotensin-converting enzyme (ACE) activity has been demonstrated in valve tissue. Thus, a case-control study was conducted to investigate any possible relationship between ACE gene polymorphisms and chronic mitral valve disease severity and calcification. METHODS: This case-control study included 82 patients (24 males, 58 females; mean age 40.3 +/- 14.7 years) with chronic rheumatic mitral valve, and 154 control subjects (53 males, 101 females; mean age 43.4 +/- 13.4 years). ACE gene insertion/deletion (I/D) polymorphisms were identified using polymerase chain reaction methods. RESULTS: Among RHD subjects, 31 (30.6%) were D/D, 25 (32.7%) were I/D, and 26 (18.8%) were I/I. Among controls, 57 (57.4%) were D/D, 69 (61.3%) were I/D, and 28 (35.2%) were I/I. The frequency of ACE I/I genotype was higher in RHD subjects than in controls (chi2 = 7.4, df = 2, p < 0.030; D/D versus I/D versus I/I), or (chi2 = 5.5, df = 1, p < 0.019; DD + ID versus II). Predisposition to RHD was significantly less frequent in the D/D genotype. There was no statistically significant difference in the genetic analysis of RHD with respect to mitral valve score, severity of mitral regurgitation and left atrial diameter. Mitral valve calcification was significantly associated with a higher frequency of I/I genotype and I/D genotype than D/D genotype alone (chi2 = 6.2, df = 2, p = 0.043). The ACE I/I genotype was associated with a predisposition to a greater risk of severe calcific valve disease. CONCLUSION: The ACE I/I genotype is more common in patients with rheumatic valve disease than in the normal population. This suggests that the ACE gene polymorphism may be involved in the pathogenesis of rheumatic heart disease.

Giant platelet disorder in the Cavalier King Charles Spaniel.

OBJECTIVE: The aim of this study was to describe the clinical, functional, and morphologic characteristics of platelets in Cavalier King Charles Spaniel dogs (Cavaliers). MATERIALS AND METHODS: Blood from 69 clinically normal Cavaliers was collected and anticoagulated with ethylenediamine-tetraacetic acid (EDTA) and citrate. Automated and manual platelet counts were obtained. Percent platelet aggregation in response to ADP (2, 4, 8, 16, and 32 microM) was determined. Electron microscopy was performed to examine platelet internal morphology and dense granule distribution. A cardiologist recorded the quality of murmurs. RESULTS: Thrombocytopenia (<100,000/microL) was present in 51.43% (36/69) of Cavaliers. Macrothrombocytes (>3 microm) were present in 33.33% (22/69). Mean manual platelet count was 118,770/microL. Manual (EDTA blood) and automated (EDTA and citrated blood) methods of platelet counting were correlated. Prevalence of cardiac murmurs was 38% (26/69). There was no association between affected dogs and murmur, signalment, or coat color. Mean percent platelet aggregation was significantly higher in controls than in Cavaliers (79% vs 38%, p=0.001). Response to ADP was unaffected by thrombocytopenia, macrothrombocytes, murmur, or any combination thereof. Platelet electron microscopy showed normal and giant sized platelets with normal internal morphology. CONCLUSIONS: A benign inherited giant platelet disorder affects approximately 50% of Cavalier King Charles Spaniels. It is characterized by thrombocytopenia, macrothrombocytes, or decreased platelet aggregation in response to ADP. Platelet ultrastructure is normal. Citrated or EDTA blood provides accurate platelet counts. Further studies are indicated to determine platelet glycoprotein structure and any association with mitral endocardiosis. Cavaliers may be useful models of inherited giant platelet disorders.

Leukocyte expression of heme oxygenase-1 [hmox1] varies inversely with severity of tricuspid regurgitation in acute pulmonary embolism.

OBJECTIVE: Pulmonary embolism (PE) can cause intracardiac hemolysis and increased plasma hemoglobin and arginase-1, which can worsen pulmonary vasoconstriction. We test the hypothesis that patients with PE that causes tricuspid regurgitation (TR), indicative of higher pulmonary arterial pressures, have decreased leukocyte expression of hmox-1 compared with patients with PE and no TR and patients without PE. DESIGN: Prospective, noninterventional study. PATIENTS: Normotensive patients with suspected PE (n=87) who underwent CT pulmonary angiography and transthoracic Doppler-echocardiography. MEASUREMENTS: Significant TR was defined as a jet velocity >2.7m/s. Leukocyte expression of hmox-1, haptoglobin, haptoglobin related gene, the haptoglobin receptor, CD163 and cox-2 genes were assessed by quantitative rtPCR, and the hmox-1 promoter was examined for the -413 A→T SNP and GT repeat polymorphisms. RESULTS: Of the 44 (50%) with PE+, 22 had TR+, and their mean pulmonary vascular occlusion (39±32%) did not differ significantly from patients who were TR- (28±26%, P=0.15). Patients with PE+ and TR+ had significantly lower expression of hmox-1 and haptoglobin genes than patients without PE+ and no TR. Expression of hmox-1 varied inversely with TR velocity (r(2)=0.45, P<0.001) for PE+ (n=22) but not patients without PE. Hmox-1 expression did not vary significantly with genotype. Cox-2 did not differ between groups and had no correlation with TR. CONCLUSIONS: Severity of TR varied inversely with hmox-1 expression, suggesting that hmox-1 expression affects pulmonary vascular reactivity after PE.