Indicator Of Pulmonary Hypertension Research Articles

343 The relationship between pulmonary arterial pressure phenotypes and oxygen consumption in beef cattle

Abstract The objective of this study was to determine if a phenotypic relationship between pulmonary arterial pressure (PAP) and oxygen consumption exists in beef cattle. Pulmonary arterial pressure is used as an indicator of pulmonary hypertension in cattle which is indicative of the susceptibility to both high-altitude disease and feedlot heart failure of an individual. Cattle with greater PAP are typically hypoxic and have initiated expression of compensatory mechanisms their cardio-pulmonary systems employ to combat this alveolar hypoxia. In turn, this causes an increase in PAP and, ultimately, right-sided heart failure. If hypoxic individuals consume more oxygen as a compensation mechanism, oxygen consumption as a trait could be used as an indicator of the prediction of PAP and feedlot heart failure and would be especially useful for cattle in deep phenotyping systems. Data used in the study included cattle with PAP measures on a total of 132 individuals. The data consisted of both steers (n = 99) and heifers (n = 33) from a ranch located in southern Wyoming at an elevation of approximately 2,195 m. After weaning on the ranch, cattle were transported to Colorado State University’s Agriculture Research, Development and Education Center located in Fort Collins, CO (elevation: 1,558 m). Oxygen consumption was measured using a Greenfeed system (C-Lock, Rapid City, South Dakota). To determine if a relationship exists between oxygen consumption and PAP, a simple linear regression model was used to regress PAP on average daily oxygen consumption. Effects included in the model were sex and phenotypic PAP. Average daily oxygen consumption was measured in kilograms per day and averaged 6.6 ± 1.66 kg with a range of 2.3 to 10.45 kg. Pulmonary arterial pressure averaged 42.6 ± 7.96 mm Hg and ranged from 33 to 81 mm Hg. In this data, sex did not account for a significant amount of variability in phenotypic PAP (P > 0.05). Oxygen consumption did account for a significant amount of variability in PAP (P < 0.05), and it was found that with every 1 kg increase of oxygen consumption, PAP is estimated to increase 1.02 mm Hg. These results indicate that a statistical relationship between oxygen consumption and PAP exists. Although these findings suggest that greater oxygen consumption leads to greater PAP, further research is required to fully comprehend the relationship between beef cattle PAP and oxygen consumption.

Association between Thoracic Radiographic Changes and Indicators of Pulmonary Hypertension in Dogs with Heartworm Disease.

Pulmonary hypertension (PH) is a consequence of pulmonary endarteritis during infection with Dirofilaria immitis in dogs. Echocardiography is the technique of choice but is not always accessible to all clinicians. This study aimed to evaluate the association of the radiological findings in dogs with heartworm disease and the presence or absence of echocardiographically characterised PH. The study included 62 heartworm-infected dogs that underwent thoracic radiographs and echocardiography. The studied dogs showed moderate to severe PH when the Right Pulmonary Artery Distensibility (RPAD) Index was <29.5%. The RPAD Index was used for comparison with thoracic radiographs. The Vertebral Heart Size (VHS), right cranial pulmonary artery passing through the fourth rib in the laterolateral projection (CrPA/R4) ratio, and right caudal pulmonary artery to the ninth rib in the dorsoventral projection (CdPA/R9) ratio showed significant differences between dogs with/without PH (p < 0.001). Sensitivity (sen) and specificity (sp) cut-off values were obtained: VHS ≥ 9.53 (sen 93.75%, sp 63.33%); CrPA/R4 ≥ 1.08 (sen 87.5%, sp 70%); and CdPA/R9 ≥ 1.10 (sen 96.88%, sp 76.66%). The CrPA/R4 and CdPA/R9 ratios showed potential as a preliminary screening tool for PH in heartworm-infected dogs, suggesting that they may reliably indicate the presence of PH and guide the decision for further diagnostic testing.

Role of CT attenuation correction gated SPECT MPI in prediction of pulmonary hypertension

ObjectiveTo elucidate the value of gated SPECT-MPI using CT attenuation correction (AC) for prediction of pulmonary hypertension (PHT) in coronary patients by estimation of reliability of non-contrast CT in measurement of main pulmonary artery diameter (MPAd) as well as by assessment of potential predictive role of gated parameters as beneficial accessory findings. BackgroundContrast-enhanced CT is known as an accurate tool for assessment of MPAd to predict PHT. [1] The low-dose non-contrast CT which is used for AC in MPI study, however, has an unclear value in precise vascular diameter measurement; it is also uncertain whether gated parameters could help to predict PHT. Methods and patientsA total of 207 patients, who had a transthoracic echocardiography and MPI with an interval of maximum one month, underwent this retrospective study. PHT was defined as a RVSP ≥36 mmHg by echocardiography; peak tricuspid regurgitation velocity (PTRV) was also calculated to use as a criterion for PHT. Of all subjects, 120 had RVSP ≥ 36 and 87 showed RVSP < 36; there also were 191 and 16 patients with PTRV ≤ 3.4 m/s and >3.4 m/s, respectively. Comparison was made unconnectedly between each group regarding the echocardiography results with the MPI parameters, with and without CT-AC, including MPAd derived from CT as well as RV/LV uptake ratio, shape index and septal wall motion and thickening scores to define the best indicators of PHT. ResultsThere was a significant association between established benchmark of PHT in echocardiography (RVSP), with MPAd derived from non-contrast CT as well as with LV shape index from gated study and RV/LV uptake ratio acquired from non-AC SPECT-MPI. Also, stress and rest RV/LV uptake ratio, MPAd, LV end-systolic and LV end-diastolic shape indexes are significantly higher in patients with RVSP ≥ 36 mmHg compare to patients with RVSP < 36 mmHg. ConclusionsGated-SPECT-MPI using CT-AC can predict PHT by reliable estimation of MPAd as well as by defining RV/LV uptake ratio and shape index, providing an added clinical value for this invaluable modality in cardiac patients.

127 Genetic Correlations Between Systolic and Diastolic Pulmonary Arterial Pressure in Beef Cattle

Abstract Pulmonary hypertension is a historical issue in high elevation beef production and is increasingly occurring in moderate elevation beef finishing systems (i.e., feedlots). Pulmonary arterial pressure (PAP) is the mean pressure (mmHg) measure in the pulmonary artery and is an indicator of pulmonary hypertension. To measure PAP, a certified veterinarian threads a catheter through the jugular vein to the heart and into the pulmonary artery. A total of 3 measures are recorded, including mean pulmonary arterial pressure (mPAP), systolic pulmonary arterial pressure (sPAP), and diastolic pulmonary arterial pressure. Systolic pressure is the pressure in the pulmonary artery during the contraction of the heart, whereas diastolic pressure is the pressure in the pulmonary artery during relaxation of the heart. For cattle living in high elevations, the Beef Improvement Federation Guidelines outline the risk of an individual by accounting for the elevation of the test and range of elevations at which that animal is expected to survive based on mPAP. The objective of this study was to estimate the genetic correlations between systolic and diastolic PAP. The data consisted of 1,352 animals with a mPAP, sPAP, and dPAP measured from 2011 to 2015. The systolic pulmonary arterial pressure has a mean of 65.4 ± 15.95 mmHg. The diastolic pulmonary arterial pressure has a mean of 18.2 ± 11.22 mmHg. Data were analyzed using a multiple trait, mixed effect animal model using the statistical software package ASReml 3.0. Fixed effects in the model included sex, birth year, wean date, and yearling date. Individual animal was included as the random effect. The respective heritabilities from the model were mPAP at 0.13 ± 0.05, sPAP at 0.9 ± 0.05 and dPAP at 0.09 ± 0.05. The phenotypic correlation between systolic and diastolic PAP was 0.18 ± 0.03, and the genetic correlation was 0.46 ± 0.32. The phenotypic correlation between sPAP and mPAP was 0.49 ± 0.02, and the genetic correlation was 0.69 ± 0.21. The phenotypic correlation between dPAP and mPAP was 0.83 ± 0.01, and the genetic correlation was 0.93 ± 0.07. Previous research with sPAP and dPAP has been conducted in humans, investigating methods to predict the likelihood of a person of developing pulmonary hypertension. These results provide a foundation to focus on how sPAP and dPAP impact the mPAP and current selection tools for a PAP measure and if the additional information could be useful for selection.

Oxygenation index and NT-proBNP as predictors of pulmonary hypertension and ventilation/perfusion mismatch in acute pulmonary embolism.

The magnitude of pulmonary artery pressure (PAP) and the extent of ventilation/perfusion (V/Q) mismatch are essential for assessing the prognosis of acute pulmonary embolism (APE). We aimed to develop a model for predicting the status of the pulmonary circulation and arterial gas exchange functions using serum levels of cardiac biomarkers and arterial oxygenation index (OI) values. This single-center, retrospective observational cohort study included 224 patients with APE. Multivariate linear regression and Poisson regression were used to test the statistical association between cardiac biomarkers, OI, PAP, and V/Q mismatch. Diagnostic efficiency was calculated from a receiver operating characteristic (ROC) curve. Serum levels of troponin I (TNI), N-terminal pro-brain natriuretic peptide (NT-proBNP), and arterial OI magnitude significantly correlated with PAP and V/Q mismatches (P < 0.05). Multivariate linear regression showed that NT-proBNP serum levels (β = 0.002, P < 0.001) and OI values (β = -0.022, P = 0.001) significantly influenced PAP. Arterial OI (β = -0.039, P < 0.001) had a significant influence on the percentage of pulmonary vascular obstruction (PVO) as determined by perfusion scanning. Poisson regression showed that OI (odds ratio: 0.995, p < 0.001) was a predictor of the number of lung segments with V/Q mismatches. ROC area under the curve (AUC) values of NT-proBNP and OI predicting pulmonary hypertension were 0.716 and 0.730, respectively, and for V/Q mismatch scanning, the results were 0.601 and 0.634, respectively. Arterial OI and serum levels of cardiac biomarkers may be used as indicators of pulmonary hypertension and V/Q mismatch.

Computed tomography measurement of pulmonary artery size in interstitial lung disease to evaluate pulmonary hypertension

Aim: To evaluate whether pulmonary artery size is indicator of pulmonary hypertension in patients with interstitial lung disease.Objective: To measure main pulmonary artery size in interstitial lung disease on CT. To compare these measurements with 2Decho findings in diagnosing the pulmonary hypertension.Materials and Methods Type of study: Prospective studyDuration of study: 1st June 2021 to 1st September 2022 Results and Conclusion: 30 patients with interstitial lung disease with suspicion of pulmonary hypertension were subjected to CT scan Among the 22 patients with dilated pulmonary artery, 64% were found to show signs of probable pulmonary hypertension on 2DEcho and remaining 36% patients were found to be negative.In the remaining 8 patients who were not having dilated pulmonary artery, only one patient showed signs of pulmonary hypertension on 2 Decho. Dilated pulmonary artery was correlated positively with 2Decho findings in pearson correlation of coefficient.Thus, dilated pulmonary artery can raise a suspicion of pulmonary hypertension in interstitial lung diseases. Therefore, pulmonary artery diameter is key for screening of suspected pulmonary hypertension

Clinical significance of dynamics between oxidative stress levels during mechanical lung ventilation in premature infants with persistent pulmonary hypertension

The aim of this study was to determine the clinical significance of the levels and dynamics of the urinary 8-hydroxy-2-deoxyguanosine, degree of pulmonary hypertension on choosing the duration and form of respiratory support in premature infants with respiratory distress syndrome in combination with perinatal asphyxia.&#x0D; Materials and methods. The levels of the urinary 8-hydroxy-2-deoxyguanosine (8-OHdG), ng/ml were determined by enzyme immunoassay (ELISA) method and the degree of pulmonary hypertension (PH) - by echocardiography in 60 premature new-borns at 26-32 weeks of gestation on the 1st and the 3rd–5th days of life. A comparative analysis of indicators was carried out in 2 groups: I – 32 children with respiratory distress syndrome (RDS); II – 28 children with RDS combined with perinatal asphyxia. All infants received a respiratory support, depending on the clinical condition, blood gas analyses, and the chest X-ray.&#x0D; Results. The level and dynamics of the urinary 8-OHdG correlated to degree of PH, form, and duration of respiratory support. Children of the group II on the 1st day of life had echocardiogram indicators of mild PH and indicators of the urinary 8-OHdG 2.27±0.39 ng/ml; by 3rd–5th days of life – level of the urinary 8-OHdG increased to 4.10±0.42 ng/ml and the level of PH – to moderate, required 76.2 % longer respiratory support compared to children of the group I.&#x0D; Conclusions. Prematurely born infants with RDS in combination with perinatal asphyxia have a higher oxidative stress (OS) levels and more significant pulmonary hypertension, which requires a longer respiratory support by 76.2 % and more often use of high frequency oscillatory ventilation (HFOV) by 9.3 %

Preoperative evaluation of pulmonary hypertension in lung transplant candidates: echocardiography versus right heart catheterization

BackgroundRight heart catheterization (RHC) and echocardiography are both routinely used for pulmonary artery systolic pressure (PASP) assessment in lung transplantation (LT) candidates, although this is not mandated by current guidelines. We aimed to explore the performance of echocardiographic PASP as an indicator of pulmonary hypertension in LT candidates, in order to assess the necessity of RHC.MethodsFrom a retrospective registry of 393 LT candidates undergoing RHC and echocardiography during 2015–2019, patients were assessed for the presence of pulmonary hypertension (PH), defined as mean pulmonary artery pressure (mPAP) above 20 mmHg, according to two methods—echocardiography and RHC. The primary outcome was the correlation between the PASP estimated by echocardiography to that measured by RHC. Secondary outcomes were the prediction value of the echocardiographic evaluation and its accuracy.ResultsThe mean value of PASP estimated by echocardiography was 49.5 ± 20.0 mmHg, compared to 42.5 ± 18.0 mmHg measured by RHC. The correlation between the two measurements was moderate (Pearson’s correlation: r = 0.609, p < 0.01). Echocardiography PASP measurements were moderately discriminative to diagnose PH, with an area under the curve (AUC) of 0.72 (95% CI 0.66–0.77). Echocardiographic overestimation of PASP of more than 10 mmHg was found in 35.0% of the patients, and underestimation was found in 11.6% of the patients.ConclusionIn the pre-surgical evaluation of LT candidates, echocardiographic estimation of PASP had moderate correlation and limited accuracy compared to the PASP measured by RHC. We thus recommend performing routine RHC to all LT candidates, regardless of the echocardiographic estimation of PASP.

Induction of Mucosal Tolerance to Collagen Type V Attenuates Hypoxic Pulmonary Hypertension

Hypoxic pulmonary hypertension (PH) can be caused by lung disease, injury, and chronic hypoxia (CH) exposure. Hallmarks for PH include recruitment of immune cells to the perivascular region of the lungs, thickening of the pulmonary arterial walls, elevated pulmonary vascular resistance and pressure, and right ventricular remodeling. These signature signs of PH are what lead to right heart failure and ultimately death. We have previously reported that 21 days of CH leads to both an upregulation of collagen type V (Col V) as well as natural T helper 17 (nTh17) cell-reactivity towards Col V in mouse pulmonary arteries without affecting the number of T regulatory cells (Tregs) in the lungs. However, it is unknown if Treg suppressive capacity and/or peripheral tolerance to autoantigens is affected by CH. Col V-specific Tregs, e.g. peripheral tolerance, can be induced by nasal instillation of Col V without adjuvant. Using right ventricular systolic pressure (RVSP) and pulmonary arterial wall thickening as indicators of PH, we hypothesized that induction of mucosal tolerance to Col V attenuates hypoxic PH in mice. Our data support this hypothesis, as both RVSP and wall thickening are lower in CH-exposed Col V-inoculated vs. vehicle-inoculated mice (Figure). Future studies will characterize the effect of CH on Treg suppressive activity, nTh17 perivascular infiltration, and nTh17-mediated Col V reactivity. In conclusion, our study suggests that induction of mucosal tolerance to Col V attenuates chronic hypoxia-induced PH.

PSI-32 Effect of pulmonary arterial pressure on reproductive performance in Angus heifers located in south central Wyoming

Abstract Pulmonary hypertension (i.e., high altitude disease) occurs in locations above 1,600 m in elevation and causes heart failure and death. Pulmonary arterial pressure scoring is an effective indicator of pulmonary hypertension and high-altitude disease. The objective of this study was to look at the effect of pulmonary arterial pressure (PAP) scoring on reproductive performance in Angus heifers. First service conception (FSC), pregnancy rate, and pulmonary arterial pressure scores were obtained from the Colorado State University Beef Improvement Center for 2,503 Angus heifers between 1995 and 2016. All spring-calving females were exposed to estrous synchronization and one-round of artificial insemination. After a 10-d holding period heifers were exposed to natural service sires for 60 days. First service conception and pregnancy rate traits were determined using ultrasonography via rectal palpation at 30 and 60 days post artificial insemination. Pulmonary arterial pressure scores were collected at ~12 mos of age. Data were analyzed with ANOVA as a completely randomized block design, blocking by birth year. Fixed effect was pulmonary arterial pressure group [high (&amp;gt;42mm Hg) vs. low (&amp;lt;42 mmHg)]. Logistic regression was used to further investigate fertility traits with PAP scores. Nodifferences were detected among pulmonary arterial pressure group for first service conception (P &amp;gt; 0.05); however, high pulmonary arterial pressure heifers had lower pregnancy rates compared to low PAP heifers (0.86 vs. 0.91 ± 0.01; P = 0.03). Logistic regression supported these findings, identifying PAP score as a significant predictor of breeding season pregnancy rate (P &amp;lt; 0.05), indicating an inverse relationship between PAP score and pregnancy rate. Cumulatively, results show an unfavorable relationship between heifers with high pulmonary arterial pressure scores and overall pregnancy rate.

Pulmonary artery enlargement is associated with pulmonary hypertension and decreased survival in severe cystic fibrosis: A cohort study.

BackgroundPulmonary artery (PA) enlargement, defined as pulmonary artery to ascending aorta diameter ratio (PA:A)>1 on computed tomography (CT), is a marker of pulmonary vascular disease in chronic lung diseases. PA enlargement is prevalent in cystic fibrosis (CF), but its relationship to hemodynamics and prognostic utility in severe CF are unknown. We hypothesized that the PA:A would have utility in identifying pulmonary hypertension (PH) in severe CF and that PA enlargement would be associated with reduced transplant-free survival.MethodsWe conducted a retrospective study of adults with CF undergoing lung transplant evaluation at a single center between 2000 and 2015. CT, right heart catheterization (RHC), and clinical data were collected. The PA:A was measured from a single CT slice. We measured associations between PA:A and invasive hemodynamic parameters including PH defined as a mPAP ≥25mmHg using adjusted linear and logistic regression models. Kaplan-Meier and adjusted Cox regression models were used to measure associations between PA:A>1, RHC-defined PH, and transplant-free survival in severe CF.ResultsWe analyzed 78 adults with CF that had CT scans available for review, including 44 that also had RHC. RHC-defined PH defined as a mPAP ≥25mmHg was present in 36% of patients with CF undergoing transplant evaluation. The PA:A correlated with mPAP (r = 0.73; 95% CI 3.87–7.80; p<0.001) and PVR (r = 0.42, p = 0.005) and the PA:A>1 was an independent predictor of PH (aOR 4.50; 95% CI 1.05–19.2; p = 0.042). PA:A>1 was independently associated with increased hazards for death or transplant (aHR 2.69; 95% CI 1.41–5.14; P = 0.003). The presence of mPAP ≥25mmHg was independently associated with decreased survival in this cohort.ConclusionsPA enlargement is associated with pulmonary hemodynamics and PH in severe CF. PA enlargement is an independent prognostic indicator of PH and decreased survival in this population.

Left Atrial Volume Index (LAVI) as an Indicator of Severity and Pulmonary Hypertension in Mitral Stenosis

Left Atrial (LA) pressure and the trans-mitral pressure gradient chronically increases in Mitral Stenosis (MS), which results in LA enlargement and Pulmonary Hypertension (PH). We investigate the Left Atrial Volume Index (LAVI) as an indicator of severity and PH in MS. Fifty-nine subjects with MS (27 men and 32 women) mean ages 41.3±9.51 y.o were included in this study. We examined the correlation of LAVI and parameters of MS severity, and PH (Planimetry, MVA-PHT, MVA-VTI, MV-PHT, MV meanPG, TRmaxPG, and EstPASP). Most of the subjects had severe MS (77%), mild PH (40%) and AF (80%). LAVI value markedly increased in this study (Mean: 83.79 ± 38.32 ml/m2). In subjects with severe MS, LAVI was significantly higher than that in moderate MS (91.88±38.41 vs 54.83±19.28, p<0.05). LAVI was significantly correlated with Planimetry, MVA-PHT, MVA-VTI, MV-PHT, MV MeanPG, and EstPASP (-0.40; -0.42; -0.29; 0.42; 0.27 and 0.29, p<0.05, respectively). LAVI cut-off value as an indicator for severe MS was 59.72 ml/m2, with the sensitivity and specificity was 75.3% and 66%, respectively. LAVI was correlated well with severity and PH parameters in MS. LAVI also can be used as an indicator for severe MS.

Clinical Retrospective Analysis of Interstitial Lung Disease Patients Associated with Pulmonary Hypertension.

BackgroundPulmonary hypertension is a common complication of interstitial lung disease. This study was conducted to retrospectively analyze the incidence of pulmonary hypertension among interstitial lung disease patients and the correlation between systolic pulmonary artery pressure (PASP) and pulmonary functions. We also intended to investigate whether antinuclear antibody (ANA) could be an effective indicator of pulmonary hypertension.Material/MethodsThere were 182 patients diagnosed with interstitial lung disease through high-resolution computed tomography (HRCT). Pulmonary hypertension was defined as an increase of mean pulmonary arterial pressure (PAPm) ≥25 mmHg (~PASP ≥40 mmHg) at rest. Severe pulmonary hypertension was defined as PAPm ≥35 mmHg. There were 104 cases including in this study. There were 67 cases from the ANA positive (ANA+) group and 37 cases from the ANA negative (ANA−) group. All study patients had pulmonary function tests, which included the measurements of maximal voluntary ventilation (MVV), residual volume (RV), total lung capacity (TLC), forced expiratory volume (FVC), vital capacity (VC), and diffusing capacity of the lungs for carbon monoxide (DLCO).ResultsThe pulmonary hypertension incidence in the study cohort was 25%, and the severe pulmonary hypertension incidence was 6.48%. The incidence of pulmonary hypertension in ANA+ cases was 22.22%. The incidence of pulmonary hypertension in the ANA− cases was 32.14%. The lung function test results showed moderate relationships between DLCO, FVC%, VC%, and PASP; no relationship between MVV, FEV1/FVC%, RV/TLC, and PASP; minimum relationship between FVC%, VC%, and PASP in the ANA+ group; and moderate relationship between FVC%, VC%, and PASP in the ANA− group.ConclusionsPulmonary hypertension occurred in 25% of the 182 interstitial lung disease patients and was negatively associated with deteriorated lung functions (specifically VC%, FVC%, and DLCO parameters). ANA level was not associated with the prognosis of pulmonary hypertension of patients with interstitial lung disease, and it did not significantly affect the correlation between PASP and pulmonary functions. Thus, ANA level did not seem to be a necessary indicator of pulmonary hypertension, and a more effective treatment method for pulmonary hypertension of patients with interstitial lung disease is urgently needed.

The maximum dimension of the inferior vena cava is a significant predictor of postoperative mortality in lung cancer patients with idiopathic interstitial pneumonia.

Several vascular measurements in computed tomography (CT) were reported to be indicators of pulmonary hypertension in chronic obstructive pulmonary disease (COPD) patients. We evaluated the usefulness of these parameters as predictors of postoperative mortality in lung cancer patients with IIP. This retrospective study was performed on 1888 patients. The following CT findings were evaluated: diameter of the main pulmonary artery, ascending aorta, and the short axis of the inferior vena cava (IVC). Univariate and multivariate analyses were conducted to determine predictors of surgical mortality. In the IIP patients, the 90-day mortality was 0.8%, and the 2-year mortality was 5.8%. Regarding the 90-day mortality in patients with IIP, a multivariate analysis revealed a short axis of IVC > 21mm [odds ratio (OR) 6.4, p < 0.01) and the risk score reported by Japanese Association for Chest Surgery (JACS) (OR 1.4, p = 0.01) as independent predictors. Regarding the 2-year mortality in patients with IIP, a multivariate analysis revealed IVC > 21mm (OR 2.3, p < 0.04), %VC < 80% (OR 2.4, p = 0.02), and pathological cancer stages II and III vs. I (OR 7.2, p < 0.001) as independent predictors. Enlargement of the IVC as measured by CT was a significant predictor of mortality after surgery for lung cancer with IIP patients.

Clinical and prognostic relationships of pulmonary artery to aorta diameter ratio in patients with heart failure: a cardiac magnetic resonance imaging study

The pulmonary artery (PA) distends as pressure increases. The ratio of PA to aortic (Ao) diameter may be an indicator of pulmonary hypertension and consequently carry prognostic information in patients with chronic heart failure (HF). Patients with chronic HF and control subjects undergoing cardiac magnetic resonance imaging were evaluated. The main PA diameter and the transverse axial Ao diameter at the level of bifurcation of the main PA were measured. The maximum diameter of both vessels was measured throughout the cardiac cycle and the PA/Ao ratio was calculated. A total of 384 patients (mean age, 69 years; mean left ventricular ejection fraction, 40%; median NT-proBNP, 1010 ng/L [interquartile range, 448-2262 ng/L]) and 38 controls were included. Controls and patients with chronic HF had similar maximum Ao and PA diameters and PA/Ao ratio. During a median follow-up of 1759 days (interquartile range, 998-2269 days), 181 patients with HF were hospitalized for HF or died. Neither PA diameter nor PA/Ao ratio predicted outcome in univariable analysis. In a multivariable model, only age and NT-proBNP were independent predictors of adverse events. The PA/Ao ratio is not a useful method to stratify prognosis in patients with HF.

Clinical significance of right ventricular activity on treadmill thallium-201 myocardial single-photon emission computerized tomography using cadmium-zinc-telluride cameras.

Identification of right ventricular (RV) abnormalities is important in patients with suspected coronary artery disease (CAD). RV activity can be better visualized on myocardial single-photon emission computerized tomography (SPECT) using a higher sensitivity cadmium-zinc-telluride (CZT) detector. The aim of this study was to investigate the clinical significance of RV/left ventricular (LV) uptake ratios during exercise thallium-201 SPECT using CZT detectors. A total of 102 patients underwent treadmill ECG-gated SPECT, coronary angiography, and echocardiography. SPECT myocardial perfusion was interpreted using a 17-segment model and a 0-4-point scale. RV/LV uptake ratios were calculated on the basis of maximum counts per pixel within the entire RV and LV walls. The relationships between RV/LV uptake ratio and gated SPECT, presence of CAD (≥50% stenosis in the left main or ≥70% in the main branches), demographics, and echocardiographic parameters were analyzed. Stress RV/LV ratios correlated positively with the presence of left main or multivessel disease, and tricuspid regurgitation maximum pressure gradient. After multivariate regression, stress/rest RV/LV ratios correlated positively with mitral flow deceleration time, age, female sex, and use of β-blockers. RV/LV uptake ratios on the basis of exercise myocardial perfusion SPECT imaging using CZT cameras are useful for the detection of severe CAD and could serve as an indicator of pulmonary hypertension and LV diastolic dysfunction.

Folic Acid Promotes Recycling of Tetrahydrobiopterin and Protects Against Hypoxia-Induced Pulmonary Hypertension by Recoupling Endothelial Nitric Oxide Synthase.

Nitric oxide (NO) derived from endothelial NO synthase (eNOS) has been implicated in the adaptive response to hypoxia. An imbalance between 5,6,7,8-tetrahydrobiopterin (BH4) and 7,8-dihydrobiopterin (BH2) can result in eNOS uncoupling and the generation of superoxide instead of NO. Dihydrofolate reductase (DHFR) can recycle BH2 to BH4, leading to eNOS recoupling. However, the role of DHFR and eNOS recoupling in the response to hypoxia is not well understood. We hypothesized that increasing the capacity to recycle BH4 from BH2 would improve NO bioavailability as well as pulmonary vascular remodeling (PVR) and right ventricular hypertrophy (RVH) as indicators of pulmonary hypertension (PH) under hypoxic conditions. In human pulmonary artery endothelial cells and murine pulmonary arteries exposed to hypoxia, eNOS was uncoupled as indicated by reduced superoxide production in the presence of the nitric oxide synthase inhibitor, L-(G)-nitro-L-arginine methyl ester (L-NAME). Concomitantly, NO levels, BH4 availability, and expression of DHFR were diminished under hypoxia. Application of folic acid (FA) restored DHFR levels, NO bioavailability, and BH4 levels under hypoxia. Importantly, FA prevented the development of hypoxia-induced PVR, right ventricular pressure increase, and RVH. FA-induced upregulation of DHFR recouples eNOS under hypoxia by improving BH4 recycling, thus preventing hypoxia-induced PH. FA might serve as a novel therapeutic option combating PH.

Differential gene expression of three nitric oxide synthases is consistent with increased nitric oxide in the hindbrain of broilers with cold-induced pulmonary hypertension

Quantitative real-time PCR and Griess reaction were conducted to evaluate gene expression of nitric oxide synthases (eNOS, nNOS and iNOS) and nitric oxide (NO) production in the hindbrain, midbrain, forebrain of chickens with cold-induced pulmonary hypertension.The ratio of the right to total ventricular weight of heart as an indication of pulmonary hypertension was increased in the cold stress groups of chickens at 42 d of age.In the pulmonary hypertensive chickens, production of NO was increased in the hindbrain but was unchanged in the forebrain and midbrain. Relative gene expression of eNOS and nNOS was upregulated in the three segments of brain, whereas the iNOS transcript was downregulated in the forebrain and midbrain of the cold-induced pulmonary hypertensive chickens.It is concluded that in the chickens with cold-induced pulmonary hypertension, variations of nNOS, eNOS and iNOS gene expression would lead to overproduction of NO in the hindbrain, whereas the variations in the expression of these genes did not result in an elevation of NO in the forebrain and midbrain. It is suggested that high levels of NO in the hindbrain excites neural mechanisms involved in pulmonary hypertension.

Abstract 15125: Percutaneous Transluminal Pulmonary Angioplasty Improves Hemodynamics and Right Ventricular Function in Patients with Chronic Thromboembolic Pulmonary Hypertension -One Year Follow-up Study

Objectives: Right ventricular function (RV) is an important prognostic indicator of pulmonary hypertension. Recent studies have demonstrated that percutaneous transluminal pulmonary angioplasty (PTPA) improves pulmonary hemodynamics in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). In this study, we examined whether PTPA also improves right ventricular dysfunction in those patients. Methods: We performed a total of 252 PTPA procedures (median 4 procedures per patient) for 56 consecutive patients with inoperable CTEPH, after stabilizing their condition using conventional pulmonary vasodilators. Among them, we enrolled 33 patients who had finished 1-year follow-up after final PTPA in the present study (female 81.8%, median age 60 yrs.). RV function was evaluated by tricuspid annular plane systolic excursion (TAPSE) on echocardiogram (42.4%, n=14) and RV ejection fraction (RVEF) on cardiac magnetic resonance imaging (39.4%, n=13) before and after PTPA. Results: No patient died during the PTPA procedure or during the 1-year follow-up period. Comparisons before and after PTPA showed marked improvement of WHO functional class III/IV (75.7 to 0%, P&lt;0.001), 6-min walking distance (316 to 480 m, P&lt;0.001), and brain natriuretic peptide level (93 to 23 pg/ml, P&lt;0.001) and significant hemodynamic improvements for mean pulmonary artery pressure (42.3±10.7 to 24.4±5.7mmHg, P&lt;0.001), cardiac index (2.2±0.6 to 2.7±0.6 L/min•m2, P&lt;0.001) and pulmonary vascular resistance (786±384 to 265±93 dyn•sec•cm5, P&lt;0.001). Furthermore, RV function was also significantly improved for both TAPSE (18.0±4.0 to 23.4±4.3mm, P&lt;0.001) and RVEF (37.9±11.0 to 52.4±7.1%, P&lt;0.001) (Figure). Conclusions: PTPA improves not only pulmonary hemodynamics but also RV function in patients with inoperable CTEPH.

Pulmonary Vascular Dimensions as an Indicator of Pulmonary Hypertension in Scleroderma

Pulmonary Vascular Dimensions as an Indicator of Pulmonary Hypertension in Scleroderma