Respiratory viruses and postoperative hemodynamics in patients with unrestrictive congenital cardiac communications: a prospective cohort study.

BACKGROUND: Pulmonary vascular abnormalities pose a risk for severe life-threatening hemodynamic disturbances following surgical repair of congenital cardiac communications (CCCs). In the distal lung, small airways and vessels share a common microenvironment, where biological crosstalks take place. Because respiratory cells infected by viruses express a number of molecules with potential impact on airway and vascular remodeling, we decided to test the hypothesis that CCC patients carrying viral genomes in the airways might be at a higher risk for pulmonary (and systemic) hemodynamic disturbances postoperatively. METHODS: Sixty patients were prospectively enrolled (age 11 [7-16] months, median with interquartile range). Preoperative pulmonary/systemic mean arterial pressure ratio (PAP/SAP) was 0.78 (0.63-0.88). The presence or absence of genetic material for respiratory viruses in nasopharyngeal and tracheal aspirates was investigated preoperatively in the absence of respiratory symptoms using real-time polymerase chain reaction (kit for detection of 19 pathogens). Post-cardiopulmonary bypass (CPB) inflammatory reaction was analyzed by measuring serum levels of 36 inflammatory proteins (immunoblotting) 4 h after its termination. Postoperative hemodynamics was assessed using continuous recording of PAP and SAP with calculation of PAP/SAP ratio. RESULTS: Viral genomes were detected in nasopharynx and the trachea in 64% and 38% of patients, respectively. Rhinovirus was the most prevalent agent. The presence of viral genomes in the trachea was associated with an upward shift of postoperative PAP curve (p = 0.011) with a PAP/SAP of 0.44 (0.36-0.50) in patients who were positive versus 0.34 (0.30-0.45) in those who were negative (p = 0.008). The presence or absence of viral genomes in nasopharynx did not help predict postoperative hemodynamics. Postoperative PAP/SAP was positively correlated with post-CPB levels of interleukin-1 receptor antagonist (p = 0.026), macrophage migration inhibitory factor (p = 0.019) and monocyte chemoattractant protein-1 (p = 0.031), particularly in patients with virus-positive tracheal aspirates. CONCLUSIONS: Patients with CCCs carrying respiratory viral genomes in lower airways are at a higher risk for postoperative pulmonary hypertension, thus deserving special attention and care. Preoperative exposure to respiratory viruses and post-CPB inflammatory reaction seem to play a combined role in determining the postoperative behavior of the pulmonary circulation.

Postoperative Pulmonary Hemodynamics and Systemic Inflammatory Response in Pediatric Patients Undergoing Surgery for Congenital Heart Defects.

There is scarce information about the relationships between postoperative pulmonary hemodynamics, inflammation, and outcomes in pediatric patients with congenital cardiac communications undergoing surgery. We prospectively studied 40 patients aged 11 (8-17) months (median with interquartile range) with a preoperative mean pulmonary arterial pressure of 48 (34-54) mmHg who were considered to be at risk for postoperative pulmonary hypertension. The immediate postoperative pulmonary/systemic mean arterial pressure ratio (PAP/SAPIPO, mean of first 4 values obtained in the intensive care unit, readings at 2-hour intervals) was correlated directly with PAP/SAP registered in the surgical room just after cardiopulmonary bypass (r = 0.68, p < 0.001). For the entire cohort, circulating levels of 15 inflammatory markers changed after surgery. Compared with patients with PAP/SAPIPO ≤ 0.40 (n = 22), those above this level (n = 18) had increased pre- and postoperative serum levels of granulocyte colony-stimulating factor (p = 0.040), interleukin-1 receptor antagonist (p = 0.020), interleukin-6 (p = 0.003), and interleukin-21 (p = 0.047) (panel for 36 human cytokines) and increased mean platelet volume (p = 0.018). Using logistic regression analysis, a PAP/SAPIPO > 0.40 and a heightened immediate postoperative serum level of macrophage migration inhibitory factor (quartile analysis) were shown to be predictive of significant postoperative cardiopulmonary events (respective hazard ratios with 95% CIs, 5.07 (1.10-23.45), and 3.29 (1.38-7.88)). Thus, the early postoperative behavior of the pulmonary circulation and systemic inflammatory response are closely related and can be used to predict outcomes in this population.

Macrophage migration inhibitory factor and chemokine RANTES in young pediatric patients with congenital cardiac communications: Relation to hemodynamic parameters and the presence of Down syndrome.

Inflammation and immunity are central in the pathobiology of pulmonary vascular disorders. Preliminary headway has been made in understanding the relationships between inflammatory proteins and clinical parameters in pediatric congenital heart disease. In this study, we analyzed serum levels of macrophage migration inhibitory factor (MIF) and regulated on activation normal T cell expressed and secreted chemokine (RANTES) in 87 patients with unrestrictive congenital cardiac communications and signs of pulmonary hypertension (age 2-36 months) and 50 pediatric controls. They were investigated in relation to clinical and hemodynamic parameters and the presence of Down syndrome. Hemodynamics was assessed by transthoracic Doppler echocardiography and cardiac catheterization. Chemokines were analyzed in serum using a chemiluminescence assay. The highest MIF levels were observed in very young subjects with heightened pulmonary vascular resistance but who presented a positive response to vasodilator challenge with inhaled nitric oxide. In contrast, RANTES levels were higher in patients with pulmonary overcirculation and congestion, correlating nonlinearly with pulmonary blood flow. Levels of both chemokines were higher in subjects with Down syndrome than in nonsyndromic individuals, but the difference was observed only in patients, not in the control group. In patients with Down syndrome, there was a direct relationship between preoperative serum MIF and the level of pulmonary artery pressure observed 6 months after surgical repair of cardiac anomalies. Thus, it was interesting to observe that MIF, which is key in the innate immune response and chemokine RANTES, which is highly expressed in respiratory viral infections were related to clinical and hemodynamic abnormalities associated with pediatric congenital heart disease.

Relation of Macrophage Migration Inhibitory Factor to Pulmonary Hemodynamics and Vascular Structure and Carbamyl-Phosphate Synthetase I Genetic Variations in Pediatric Patients with Congenital Cardiac Shunts.

Macrophage migration inhibitory factor (MIF) plays an important pathophysiological role in pulmonary hypertension (PHT). Previously, we demonstrated that serum MIF is increased in pediatric PHT associated with congenital heart disease (CHD). In the present study, we determined possible associations between MIF levels, hemodynamic and histological parameters, and mitochondrial carbamyl-phosphate synthetase I (CPSI) T1405N polymorphism in a similar population. The asparagine 1405 variant (related to A alleles in the C-to-A transversion) has been shown to be advantageous in pediatric PHT compared to the threonine 1405 variant (C alleles). Forty-one patients were enrolled (aged 2-36 months) and subsequently divided into 2 groups after diagnostic evaluation: the high-pulmonary blood flow (high PBF) group (pulmonary-to-systemic blood flow ratio 2.58 (2.21-3.01), geometric mean with 95% CI) and the high-pulmonary vascular resistance (high PVR) group (pulmonary vascular resistance 6.12 (4.78-7.89) Wood units × m2). Serum MIF was measured using a chemiluminescence assay. The CPSI polymorphism was analyzed by polymerase chain reaction followed by high-resolution melting analysis. Medial hypertrophy of pulmonary arteries was assessed by the histological examination of biopsy specimens. Serum MIF was elevated in patients compared to controls (p = 0.045), particularly in the high-PVR group (n = 16) (p = 0.022) and in subjects with the AC CPSI T1405N genotype (n = 16) compared to those with the CC genotype (n = 25) (p = 0.017). Patients with high-PVR/AC-genotype profile (n = 9) had the highest MIF levels (p = 0.030 compared with the high-PBF/CC-genotype subgroup, n = 18). In high-PVR/AC-genotype patients, the medial wall thickness of intra-acinar pulmonary arteries was directly related to MIF levels (p = 0.033). There were no patients with the relatively rare AA genotype in the study population. Thus, in the advantageous scenario of the asparagine 1405 variant (AC heterozygosity in this study), heightened pulmonary vascular resistance in CHD-PHT is associated with medial hypertrophy of pulmonary arteries where MIF chemokine very likely plays a biological role.

Phosphodiesterase type 5 inhibitors improve microvascular dysfunction markers in pulmonary arterial hypertension associated with congenital heart disease.

BACKGROUND: Ideally, vasodilator therapies for pulmonary arterial hypertension (PAH) should have a favorable impact on markers of vascular dysfunction, in addition to their known effects on hemodynamics, cardiac function, and patient's physical capacity. METHODS: We analyzed circulating (plasma) markers of endothelial and platelet activation/dysfunction (enzyme-linked immunoassays) in the specific setting of advanced PAH associated with congenital heart disease, during the course of sildenafil and tadalafil therapies. Thirty-one patients were enrolled (age 10-54 years), most of them with chronic hypoxemia and elevated hematocrit. Drugs were administered orally for 6 months (sildenafil [n = 16], 20 mg t.i.d.; tadalafil [n = 15], single daily dose of 40 mg). Measurements were performed at baseline, and 90 and 180 days. RESULTS: Compared to controls, patients had elevated baseline ß-thromboglobulin (ß-TG, P = .002), P-selectin (P = .027), tissue-type plasminogen activator (t-PA, P = .009), and von Willebrand factor antigen (VWF:Ag, P = .010). Thrombomodulin was importantly reduced (TM, P < .001), while soluble CD40 Ligand was not changed (P = .320). Tadalafil administration was associated with improvement of ß-TG (P = .004), t-PA (P = .003) and TM (P = .046) levels, while P-selectin was improved by sildenafil treatment only (P = .034). VWF:Ag improved transiently in the sildenafil group (P = .019). Both therapies were associated with improvement of the physical capacity (functional class and distance walked during the 6-minute test, P < .05), hematocrit and hemoglobin level (P < .05), and health-related quality of life (physical and mental components, P < .05). CONCLUSION: In PAH associated with congenital heart disease, phosphodiesterase 5 inhibitors seem to have beneficial actions at microcirculatory level, beyond the proposed effects as vasodilators.

Factors influencing outcomes in patients with Eisenmenger syndrome: a nine-year follow-up study.

In patients with Eisenmenger syndrome, life expectancy is usually longer than in patients with other forms of pulmonary arterial hypertension (PAH). We conducted a cohort study in which patients were followed over a long period of time in an attempt to identify potential predictors of clinical outcomes. Sixty-seven treatment-naïve patients were enrolled (age range = 12-60 years; median age = 33 years). Baseline demographic, diagnostic, and functional parameters, plasma levels of endothelial dysfunction markers, and treatment-related data were tested for possible correlations with event-free survival. Patients were started on oral PAH drugs at the beginning of follow-up (n = 23), during follow-up (n = 33), or remained untreated (n = 11). The duration of follow-up was 0.54-9.89 years (median = 7.13 years), with an overall survival rate of 82% and an event-free survival rate of 70%. The estimated mean for event-free survival time was 7.71 years (95% confidence interval [CI] = 6.86-8.55 years). Of the 16 variables that were analyzed, the duration of exposure to PAH drugs was identified as an independent protective factor (hazard ratio [HR] = 0.25 for quartiles, 95% CI = 0.14-0.47, P < 0.001). The initial functional class (HR = 3.07; 95% CI = 1.01-9.34; P = 0.048), the severity of right ventricular dysfunction (HR = 2.51 [mild, moderate or severe dysfunction]; 95% CI = 1.22-5.19; P = 0.013) and plasma von Willebrand factor concentration (HR = 1.74 for quartiles; 95% CI = 1.07-2.83; P = 0.026) were identified as risk factors. The length of exposure to oral PAH therapies influences survival favorably in Eisenmenger patients. This may be of interest for communities where access to medications is restricted.

Outside-in, inside-out: Proteomic analysis of endothelial stress mediated by 7-ketocholesterol.

Oxysterols are cholesterol oxidation products formed through enzymatic or autoxidation mechanisms. 7-ketocholeterol (7KC) is one of most abundant oxysterols found in atherosclerotic lesions. Its role in atherosclerosis pathogenesis has been broadly studied in a variety of models. The arterial microenvironment is a multicellular dynamic compartment that, among other systemic factors, is continuously stimulated by 7KC. Endothelial cells have a key role on that environment, being in intimate contact with both the blood stream and the vessel wall, the site of disease origin. 7KC has been shown to promote endothelial cell death and/or dysfunction, depending on its concentration. However, its contribution to the cell microenvironment through cell stimulation has not received much attention. Here we applied mass spectrometry-based proteomics followed by bioinformatics workflow to analyze the effect of a non-toxic 7KC concentration on endothelial cell protein expression and secretion in vitro. Trypsin digests were prepared from the secretome of the endothelial cells and from the total cell pellet after 24h exposure to 7KC. All samples were analyzed by high resolution and accurate mass nano-LC MS/MS. After database search and statistical analysis, differentially expressed proteins were selected for further studies. Our workflow identified 1805 secreted proteins and 2203 intracellular proteins, and of these, 48 and 53, respectively, were regulated. Regulated proteins upon 7KC exposure are involved in unfolded protein response, vascular homeostasis, and reduced control of angiogenesis. Moreover, blood coagulation was another main pathway regulated through Tissue Factor Pathway Inhibitor (TFPI), an antithrombotic agent associated with coronary disease that we found to be more than 2 times downregulated. Taken together, these data show differential endothelial protein regulation and secretion upon 7KC exposure for short time periods under non-toxic conditions. Herewith, these data support the role of 7KC in atherosclerosis pathophysiology and thus reinforce the deleterious effect of endothelial cells stress in the arterial microenvironment.

Platelet protease-activated receptor 1 and membrane expression of P-selectin in pulmonary arterial hypertension.

INTRODUCTION: Pulmonary arterial hypertension (PAH) is frequently associated with thrombotic events, particularly involving the pulmonary microcirculation at sites of vascular injury. We therefore decided to analyse protease-activated receptor 1 (PAR1), a key element in the activation of human platelets by thrombin, in PAH patients in stable clinical condition. METHODS: Using flow cytometry, we analyzed platelet PAR1 density, PAR1-mediated exposure of P-selectin and the formation of platelet-leukocyte aggregates in 30 PAH patients aged 11 to 78 years (median 50.5 years). The control group consisted of 25 healthy subjects with the same age range as patients. RESULTS: In patients, total platelet PAR1 density and uncleaved PAR1 density correlated negatively with platelet count (r(2)=0.33 and r(2)=0.34 respectively, p<0.0015). In patients with a low platelet count (<150x10(9) platelets/L), both densities were increased relative to controls (82% and 33% respectively, p<0.05). Thrombin peptide-induced platelet exposure of P-selectin was directly related to total and uncleaved PAR1 density (respectively, r(2)=0.33 and r(2)=0.29, p<0.0025) and increased in subjects with low platelet count (46% versus those with normal platelet count, p<0.05). Patients with low platelet count had decreased in vitro thrombin-induced formation of platelet-leukocyte aggregates (57% decrease versus controls, p<0.05). CONCLUSIONS: There seems to be a subpopulation of PAH patients with increased propensity to thrombotic events as suggested by increased platelet PAR1 expression and PAR-mediated surface exposure of P-selectin associated with decreased platelet count.

Altered endothelial function following the Fontan procedure.

OBJECTIVE: Thrombosis has been widely described after the Fontan procedure. The vascular endothelium plays a central role in the control of coagulation and fibrinolysis. The aim of this study was to investigate if patients undergoing a modified Fontan procedure have impaired endothelial function and fibrinolysis in the late postoperative course. PATIENTS AND METHODS: We compared 23 patients aged from 7 to 26 years with age-matched healthy volunteers, collecting blood samples prior to and following standardized venous occlusion testing. Plasma levels of von Willebrand factor antigen, tissue-type plasminogen activator antigen, plasminogen activator inhibitor-1, and D-dimer were measured with enzyme-linked immunosorbent assay. RESULTS: We found increased plasma levels of von Willebrand factor antigen in patients when compared to controls (p = 0.003). At the basal condition, concentrations of tissue-type plasminogen activator antigen and plasminogen activator inhibitor-1 antigen in the plasma, as well as their activity, were not significantly different between patients and controls. Following venous occlusion, concentrations of tissue-type plasminogen activator antigen in the plasma were significantly increased both in patients and controls, compared to pre-occlusion values. D-dimer was within the reference range. Multivariate discriminant analysis differentiated patients and their controls on the basis of differences for plasminogen activator inhibitor-1 and von Willebrand factor antigen (p = 0.0016). CONCLUSIONS: Our data suggest that patients with the Fontan circulation may have endothelial dysfunction, as indicated by raised levels of von Willebrand factor. Fibrinolysis seems to be relatively preserved, as suggested by appropriate response to venous occlusion.

Increased tyrosine phosphorylation of platelet proteins including pp125(FAK) suggests endogenous activation and aggregation in pulmonary hypertension.

Despite of several lines of evidence indicating a pathophysiologic role of platelets in pulmonary hypertension, the occurrence of chronic endogenous platelet activation has been a matter of debate. It was hypothesized that the pattern of tyrosine phosphorylation of platelet proteins examined ex vivo could provide information on the state of platelet activation. This was examined in 10 patients with pulmonary arterial hypertension aged 18 to 53 years. Phosphotyrosine density and the amounts of specific proteins were analyzed in resting platelets after reaction with anti-phosphotyrosine, anti-pp60(s-src), anti-pp125(FAK), and anti-alphaIIbbeta3 antibodies. There was a 79% increase in protein-associated phosphotyrosine in patients in comparison to levels in controls (p<0.05). In particular, phosphorylation on tyrosine residues of pp120 and pp125(FAK) increased 24% and 57%, respectively (p<0.05). Although pp60(s-src)-associated phosphotyrosine was not altered in the patient group as a whole, it was clearly decreased in three subjects. Platelet content of beta3 integrin, pp60(s-src), and pp125(FAK), was not altered. This pattern of phosphorylation suggests an ongoing process of platelet activation. Because phosphorylation of pp125(FAK) is a late, integrin-dependent event, results suggest that platelet activation and aggregation occur in vivo in these patients.

Markers of endothelial dysfunction and severity of hypoxaemia in the Eisenmenger syndrome.

Endothelial dysfunction has been reported in hypoxaemic patients with the Eisenmenger syndrome, but a direct correlation between levels of endothelial markers and the severity of hypoxaemia has not been explored. With this in mind, we compared the levels in the plasma of tissue-type plasminogen activator, thrombomodulin, and von Willebrand factor in 25 patients with the Eisenmenger syndrome. They had a median age of 31 years, and were divided into 2 groups according to their recent clinical history. Thus, 18 patients were stable, being in functional class II or III, seen as outpatients, and having peripheral saturations of oxygen of 89 plus or minus 5 percent. In contrast, 7 patients were unstable, showing episodes of symptoms placing them in functional class IV, requiring care in hospital, and manifesting saturations of oxygen of 77 plus or minus 5 percent. We were able to follow 12 patients, 8 who were stable and 4 unstable, for 24 months. At baseline, levels of von Willebrand factor were higher in the unstable patients when compared to those who were stable, at 142 plus or minus 29 and 110 plus or minus 25 units per decilitre, respectively (p equal to 0.013). This correlated positively with oxygen desaturation (p less than 0.020). The structural abnormalities also correlated positively with the magnitude of hypoxaemia (p less than 0.020). Levels remained higher in the unstable patients throughout the period of follow-up (p equal to 0.006). Tissue-type plasminogen activator was also increased, at 14.3 plus or minus 8.4 versus 6.5 plus or minus 2.7 nanograms per millilitre in controls (p less than 0.001), whereas thrombomodulin was decreased, with values of 14.4 versus 34.6 nanograms per millilitre in controls (p for median values of less than 0.001). There was no correlation with saturations of oxygen. We conclude that measurement of von Willebrand factor, as compared with tissue-type plasminogen activator and thrombomodulin, will prove a better marker of endothelial response to hypoxaemia in patients with the Eisenmenger syndrome.

Evidence of endothelial dysfunction in patients with functionally univentricular physiology before completion of the Fontan operation.

INTRODUCTION: Postoperative thrombosis after a cavopulmonary connection has been widely described. Abnormalities in coagulation seem to occur early in the course of patients with functionally univentricular physiology, and may precede surgery. Endothelial abnormalities due to chronic hypoxia, and hyperviscosity, may contribute to this scene. The purpose of our study was to investigate if patients with a superior cavopulmonary connection have altered levels of endothelial and coagulative markers in the plasma. METHODS: We compared findings in 10 patients, aged from 4 to 19 years, with 6 age-matched normal controls. We measured levels of von Willebrand factor antigen, thrombomodulin, tissue-type plasminogen activator, plasminogen activator inhibitor-1 and d-dimer in the plasma using enzyme-linked immunosorbent assay. RESULTS: We found increased levels of von Willebrand factor antigen (p = 0.01), tissue-type plasminogen activator (p = 0.01), and decreased levels of thrombomodulin (p = 0.008) in the patients when compared to controls, while levels of plasminogen activator inhibitor-1 were not different. Values of d-dimer were within the reference range. Levels of tissue-type plasminogen activator had a positive correlation with von Willebrand factor antigen (r = 0.66, p = 0.008). CONCLUSIONS: Altered levels of endothelial markers in the plasma, in the presence of normal levels of d-dimer, suggest that endothelial dysfunction may precede the occurrence of intravascular coagulation and thrombosis in patients with functionally univentricular physiology. These observations may have therapeutical implications.

Age-dependent likelihood of in situ thrombosis in secondary pulmonary hypertension.

Pulmonary arterial thrombosis (PAT) may complicate the clinical course of pulmonary hypertension associated with congenital heart disease (so-called Eisenmenger syndrome, ES). In this study, variables were sought that could represent risk factors for the occurrence of this complication. Twenty patients aged 11 to 53 (median, 33) years were studied. The presence of PAT (spiral computed tomography angiography) was correlated with age, gender group, PAP, hematocrit, peripheral oxygen saturation (SpO(2)), and plasma levels of endothelial and coagulation dysfunction markers: von Willebrand factor antigen (vWF:Ag), tissue plasminogen activator (t-PA), and D-dimer (enzyme immunoassay). Patients were classified according to the presence (group 1, N=7), or absence (group 2, N=13) of PAT. Group 1 patients were older (42+/-8 vs. 27+/-10 years in group 2, p=0.0051), had lower SpO(2) (82+/-7% vs. 89+/-6% in group 2, p=0.0462) and increased D-dimer levels (637 vs. 149 ng/mL in group 2, median values, p=0.0235). A trend was observed toward an increase in vWF:Ag (125+/-29 vs. 103+/-18 U/dL in group 2, p=0.0789) and t-PA (15.7 vs. 9.4 ng/mL in group 2, median values, p=0.0689). Age was the main variable influencing the occurrence of PAT in multivariate analysis (p=0.0026), with odds ratio of 1.204 per year. The age of 35 years was 86% sensitive and 85% specific for occurrence of PAT. Age correlated positively with t-PA (r=0.57, p=0.0111). Thus, PAT is highly prevalent in ES as an age-dependent event, probably associated with endothelial dysfunction. Prophylactic anticoagulation should be considered before the age of 30 years, in particular in subjects with low SpO(2) and increased D-dimer levels.