Pulmonary Artery Blood Flow Velocity Research Articles

Fetal Thoracic Circumference and Lung Volume and Their Relation to Fetal Size and Pulmonary Artery Blood Flow.

Research on early origins of lung disease suggests the need for studying the relationships of thoracic and lung size with fetal size and pulmonary circulation. The primary aim of this study is therefore to explore the associations between fetal thoracic circumference, lung volume, and fetal size. We also aim to assess if lung volume and thoracic circumference are associated with fetal pulmonary artery blood flow velocity measures. Cross-sectional assessment of singleton pregnancies from the general population (n=447) at 30 gestational weeks (GW) was performed using ultrasound measurement of fetal thoracic circumference, lung volume, head and abdominal circumference, and femur length. We obtained Doppler blood flow velocity measures from the proximal branches of the fetal pulmonary artery. Associations between variables were studied using Pearson's correlation and multiple linear regression analyses. Both thoracic circumference and lung volume correlated with fetal size measures, ranging from r=0.64 between thoracic circumference and abdominal circumference, to r=0.28 between lung volume and femur length. Adjustment for gestational age, maternal nicotine use, pre-pregnancy body mass index, and fetal sex marginally influenced the associations with abdominal circumference. The correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures were weak (r ≤ 0.17). We found moderate to low correlation between thoracic circumference, lung volume, and fetal size at 30 GW. The closest relationship was with the abdominal circumference. We found low correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures.

Evaluation of pulmonary artery blood flow and right heart function using phase-contrast magnetic resonance imaging in elderly patients with chronic obstructive pulmonary disease

Objective To investigate the value of phase-contrast magnetic resonance imaging(PC-MRI)in evaluating pulmonary artery blood flow and right ventricular(RV)function in elderly patients with chronic obstructive pulmonary disease(COPD). Methods Twenty-four elderly patients with COPD admitted to Beijing Anzhen Hospital between February 2016 and June 2017 were enrolled in this retrospective study.Based on pulmonary artery pressure evaluated by right heart catheterization, COPD patients were divided into a pulmonary hypertension group(PH group, n=12)and a non-PH group(n=12). Pulmonary artery blood flow velocity and volume, pulmonary arterial compliance and right heart function parameters including ejection fraction, end-diastolic volume, end-systolic volume and cardiac output, and 6-min walking distance evaluated by PC-MRI were compared between the two groups. Results There were significant differences in peak flow velocity[(88.1±16.0)cm/s vs.(59.8±13.8)cm/s, P=0.005], flow volume[(80.7±22.0)ml/s vs.(53.2±26.7)ml/s, P=0.012], main pulmonary artery compliance[(42.3±14.6)vs.(22.7±10.8), P=0.001], right ventricular ejection fraction[(48.4±13.4)% vs.(37.6±11.1)%, P=0.000], end-diastolic volume[(64.6±22.5)ml vs.(72.5±22.8)ml, P=0.030]and end-systolic volume[(50.6±33.1)ml vs.(41.7±33.1)ml, P=0.040]between the non-PH and PH groups, while there was no significant difference in cardiac output between the non-PH and PH groups[(34.2±10.8)ml vs.(34.4±8.3)ml, P=0.080]. Pearson's correlation analysis showed that 6-minute walking distance had good correlations with right ventricular ejection fraction(r=0.49), forced expiratory volume in 1 s(FEV1)(r=0.60)and main pulmonary artery diameter(r=-0.61). Conclusions PC-MRI is a noninvasive imaging method for quantitative analysis of pulmonary artery dynamics and right heart function for the elderly with COPD, and it can provide information for evaluating therapeutic effects and prognosis. Key words: Magnetic resonance imaging; Pulmonary disease, chronic obstructive; Pulmonary artery; Ventricular function

Abstract 17145: Outcomes of Transcatheter Occlusion of Patent Ductus Ateriouses in Infants ≤ 6 Mouths

Objectives: We sought to analyze the outcomes of transcatheter patent ductus arteriosus (PDA) occlusion using a variety of devices in infants ≤ 6 mouths and discuss the transcatheter occlusion indication of PDA in early infants. Methods and Results: A total of 72 patients underwent successful transcatheter device closure. The mean age at catheterization was 4.9±1.8months (1-6 months) with a mean weight at catheterization of 5.1±1.9kg (1.9-6.7kg), the mean PDA diameter of 3.9±0.8mm (1.8-5.3mm),the mean systolic pulmonary arteriosus pressure of 55.7±8.9 mmHg (46-79mmHg). Among these suffered infants, companied with 72cases of growth retardation, 48 cases of recurrent lower respiratory tract infection, 35 cases associated with congestive heart failure, and 5 cases of respirator-oxygen-dependent. 4/6-8/10 PDA occluder was selected for transcatheter device closure, and intraoperative blood transfusion were performed in 46 cases. All subjects resulted with occluder position in good shape, no residual shunt; whileas 16 cases with aortic blood flow velocity increased slightly, 12 cases with left pulmonary artery blood flow velocity increased slightly just postoperation. And in follow-ups the increased velocity of and pulmonary blood flow gradually returned to normal. Follow-up data showed, all subjects resulted good outcomes with growth significantly improved, congestive heart failure cured and repeated lower respiratory tract infection significantly reduced postoperative. Conclusions: In experienced heart center, percutaneous closure of PDA should be considered even in infants ≤ 6 mouths. The indications include PDA infants with respirator-oxygen-dependent, congestive heart failure, and recurrent lower respiratory tract infection and growth retardation. Children underwent PDA occlusion would result with improved growth and development, recovered heart function and less lower respiratory tract infection.

Emergency and sub-emergency transcatheter closure of patent ductus arteriosus in infants

Objective To explore the effects and follow-up findings of emergency and sub-emergency transcatheter closure of patent ductus arteriosus (PDA) in infants. Methods A retrospective study was performed to analyze the effects, complications, immediate and mid-term follow-up outcomes in 12 infants with PDA from Guangzhou Women and Children's Medical Center between March 2008 and April 2014 in order to evaluate the efficacy and safety of transcatheter closure of PDA in infants.All cases were diagnosed preoperatively as pneumonia, and 10 cases had congestive heart failure.Pulmonary symptoms showed no obvious change after regular internal medicine therapies. Results Twelve devices (100%) were successfully implanted.Echocardiogram was performed 3 days after the procedures and showed no residual shunt in any case.Left ventricular end-diastolic dimension[(31.3±5.4) mm], left atrial diameter[(18.2±3.4) mm], left ventricular ejection fraction(LVEF)[(56.8±8.7)%], pulmonary artery systolic pressure and mitral regurgitation were decreased or alleviated in contrast with those before the procedures(all P 0.05). Left pulmonary artery blood flow velocity was increased in 3 cases.The maximal descending aorta blood flow velocity was 1.9 m/s and 2.4 m/s respectively in 2 cases, blood flow velocity of left pulmonary artery and descending aorta were blow 2.3 m/s, pressure gradient was less than 2.9 kPa in 23-28 months after the procedure and no patient received any other intervention. Conclusions Emergency and sub-emergency transcat-heter closure of PDA in infants is safe and feasible, but long-term follow-up is needed in patients with increased left pulmonary artery blood flow velocity and/or descending aorta blood flow velocity. Key words: Patent ductus arteriosus; Interventional therapy; Emergency and sub-emergency; Infant

Pulmonary Circulatory Effects of Norepinephrine in Newborn Infants with Persistent Pulmonary Hypertension

To evaluate the respiratory and the pulmonary circulatory effects of norepinephrine in newborn infants with persistent pulmonary hypertension (PPHN)-induced cardiac dysfunction. Inclusion criteria were: 1) Newborn infants >35 weeks gestational age; 2) PPHN treated with inhaled nitric oxide; and 3) symptoms of circulatory failure despite adequate fluid resuscitation. Lung function and pulmonary hemodynamic variables assessed with Doppler echocardiography were recorded prospectively before and after starting norepinephrine. Eighteen newborns were included (gestational age: 37 +/- 3 weeks; birth weight: 2800 +/- 700 g). After starting norepinephrine, systemic pressure and left ventricular output increased respectively from 33 +/- 4 mm Hg to 49 +/- 4 mm Hg and from 172 +/- 79 mL/kg/min to 209+/-90 mL/kg/min (P < .05). Although the mechanical ventilatory variables have not been changed, the post-ductal transcutaneous arterial oxygen saturation increased from 89% +/- 1% to 95% +/- 4%, whereas the oxygen need decreased from 51% +/- 24% to 41% +/- 20% (P < .05). The pulmonary/systemic pressure ratio decreased from 0.98 +/- 0.1 to 0.87 +/- 0.1 (P < .05). Mean left pulmonary artery blood flow velocity increased by 20% (P < .05). Norepinephrine may improve lung function in newborn infants with PPHN through a decrease in pulmonary/systemic artery pressure ratio and improved cardiac performance.

Relationship between fetal pulmonary artery blood flow velocity waveform and fetal lung length in pregnancies complicated by oligohydramnios

Objectives: The objective of this study is to evaluate weather there is a correlation between Doppler velocity waveform parameters obtained from fetal pulmonary artery and fetal lung length considered as one of the lung hypoplasia risk parameters in pregnancies complicated by oligohydramnios.Methods: A total of 35 singleton pregnancies between 26 and 39 weeks complicated by oligohydramnios due to premature rupture of the membranes, placental insufficiency or idiopathic etiology and 69 normal pregnancies were examined by real time ultrasonography, color and pulse Doppler. Pulse Doppler signal was obtained from the distal part of right or left pulmonary artery after visualization with color Doppler at the level of four chamber view. The systolic to diastolic ratio, resistance index and pulsatility index were used to quantify velocity waveforms. The right lung of the fetus was measured longitudinally from the apex next to clavicle to the base at the top of diaphragm. The results of fetal lung length measurements were compared with namogram given by Roberts.Results: Statistically significant difference in distal pulmonary artery pulsatility index between normal pregnancies (1.74 ± 0.23) and pregnancies complicated by oligohydramnios (2.72 ± 0.56) with decreased value of fetal lung length (below fifth percentile) was observed. The sensitivity, specificity, positive and negative predictive value of 95, 91, 93, 91%, respectively, were obtained. In the group with oligohydramnios and normal values of fetal lung length, the difference in pulsatility index in comparison with normal pregnancies was not significant. No differences in systolic to diastolic ratio and resistance index between examined groups were found.Conclusions: Strong relationship between increased pulsatility index value obtained from distal part of pulmonary artery and decreased value of fetal lung length measurement in pregnancies complicated by oligohydramnios was observed. The measurement of pulmonary artery pulsatility index enriched with fetal lung length may give additional information useful in predicting pulmonary hypoplasia risk.

Continuous negative extrathoracic pressure and cardiac output —a pilot study

Continuous negative extrathoracic pressure (CNEP) has been recently reintroduced as therapy for respiratory failure. To determine its effects on cardiac output a pilot study was performed in ten patients aged 2 months-3 years (median 4 months). All had chronic respiratory failure (seven with bronchopulmonary dysplasia). Five were breathing spontaneously and five were intubated and undergoing intermittent positive pressure ventilation. Transcutaneous oxygen saturation and PCO2, together with ECG were continuously monitored. Pulmonary artery blood flow velocity was measured non-invasively using pulsed wave Doppler. The 95% confidence intervals for the changes with and without CNEP in spontaneously breathing and ventilated patients showed no statistically significant changes in heart rate, O2 saturation, transcutaneous PCO2 or cardiac output. This study shows that the use of CNEP, administered in a tank respirator, does not lead to large changes in cardiac output.

Measurement of Pulmonary Blood Flow with Transesophageal Two-dimensional and Doppler Echocardiography

Transesophageal echocardiography permits measurement of the pulmonary artery diameter (two-dimensional echocardiography) and pulmonary artery blood flow velocity (pulsed-wave Doppler). These measurements considered with the heart rate allow for the determination of pulmonary artery blood flow, which is equivalent to cardiac output. This study compared the precision of transesophageal Doppler-derived cardiac output (DdCO) with the precision of thermodilution cardiac output (TdCO) and examined the agreement between DdCO and TdCO in 33 cardiac surgical patients. The proximal pulmonary artery diameter was measured in triplicate during systole and end expiration, and the local blood flow velocity was recorded on video tape. The instantaneous pulmonary artery blood flow velocity (centimeters per second) for three random cardiac beats was integrated with respect to time. DdCO was calculated as the product of the flow velocity integral (centimeters per beat), heart rate (beats per min), and the mean cross-sectional area (centimeters squared) of the main pulmonary artery. At the same time that the velocity recordings were made, three serial determinations of TdCO were made by an independent observer. Pulmonary blood flow could be measured in 25 of the 33 patients. The anatomical relationship among the esophagus, the left main stem bronchus, and the pulmonary artery did not allow adequate imaging of the pulmonary artery in 8 (24%) of the patients. A total of 45 sets of triplicate measurements were made. The range of cardiac outputs encountered was 1.7-6.6 l.min-1 by TdCO and 1.5-6.9 l.min-1 by DdCO. The 95% confidence limits for the difference between the two methods (agreement) was 0.030 +/- 0.987 l.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler-echocardiographic findings in a patient with persisting right ventricular sinusoids

The Doppler-echocardiographic features of persisting right ventricular myocardial sinusoids are presented. An 18-year-old patient with persisting right ventricular sinusoids had undergone comissurotomy for critical pulmonary artery stenosis at the age of 12 months. Follow-up catheterization at the age of 17 years revealed no signs of residual pulmonary artery stenosis, outflow tract obstruction or pulmonary hypertension. No shunt could be documented. High systolic velocity jets within the myocardial sinusoids were recorded by means of continuous-wave Doppler. Pulmonary artery blood flow velocity was recorded mainly consequent to atrial contraction and was reduced during right ventricular ejection period, thus reflecting impaired systolic and diastolic right ventricular function.

Haemodynamic effects of atropine during halothane or isoflurane anaesthesia in infants and small children.

In this study, two-dimensional and pulsed Doppler echocardiography were used to measure cardiovascular changes before and after IV atropine in 31 infants and small children during halothane (n = 15) or isoflurane (n = 16) anaesthesia. Prior to induction of anaesthesia heart rate (HR), mean blood pressure (MBP), and two-dimensional echocardiographic dimensions of the left ventricle and pulmonary artery blood flow velocity were measured by pulsed Doppler echocardiography. Cardiovascular measurements were repeated while anaesthesia was maintained at 1.5 MAC halothane (n = 15) or isoflurane (n = 16). Atropine 0.02 mg.kg-1 IV was then administered and two minutes later, a third set of cardiovascular data was obtained. Heart rate decreased during halothane anaesthesia but did not change significantly during isoflurane anaesthesia. Mean blood pressure, cardiac output (CO) and stroke volume (SV) decreased similarly during 1.5 MAC halothane or isoflurane anaesthesia. Ejection fraction (EF) decreased and left ventricular end-diastolic volume (LVEDV) increased significantly in both groups, but decreases in EF (32 +/- 5 per cent vs 18 +/- 5 per cent) and increases in LVEDV (18 +/- 7 per cent vs 7 +/- 5 per cent) were significantly greater during halothane than during isoflurane anaesthesia. Following atropine, HR increased more in the patients maintained with halothane (31 +/- 6 per cent), than during isoflurane anaesthesia (18 +/- 5 per cent). Atropine increased CO in both groups of patients, but SV and EF remained unchanged. When compared with awake values, HR increased similarly and significantly (18 +/- 4 per cent) following atropine in both groups, and CO returned to control levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of blood flow velocity in the hypertensive canine pulmonary artery.

Pulmonary artery blood flow velocity was measured in 15 dogs by a recently developed direct intraluminal pulsed Doppler technique. Changes in velocity characteristics under conditions of experimentally induced hypoxic pulmonary hypertension were observed. Experimental conditions (fractional inspired oxygen concentration = 0.10) produced significant increases in mean pulmonary artery pressure and pulmonary vascular resistance. Overall and maximal negative velocity increased with pulmonary hypertension. Negative velocity occurred predominantly in the posterior half of the pulmonary artery during both control and experimental conditions. With pulmonary hypertension, diastolic negative velocity increased only in the posterior half of the pulmonary artery and systolic negative velocity decreased only in the anterior half. More basic knowledge of pulmonary artery blood flow characteristics may facilitate an informed approach to noninvasive detection of pulmonary hypertension. Direct measurements by this recently developed intraluminal technique will be useful in studying various conditions with altered pulmonary blood flow.

Diastolic forward blood flow in the pulmonary artery detected by doppler echocardiography

The etiology of diastolic motion of the pulmonary valve seen on the M-mode echocardiogram has been the subject of much debate. To further investigate diastolic events in the pulmonary artery, the patterns of diastolic pulmonary artery blood flow velocity were studied using pulsed Doppler echocardiography in patients with a normal heart. Two diastolic waveforms were found, one in early diastole related to passive filling of the right ventricle and one in late diastole related to atrial contraction. These waveforms were also related to the two recognized phases of diastolic pulmonary valve motion detected by M-mode echocardiography. The presence of biphasic diastolic blood flow in the pulmonary artery was confirmed by electromagnetic flow velocimetry in four additional patients with various cardiac diseases and normal right heart pressures. It is concluded that both atrial contraction and passive right ventricular filling produce blood flow in the pulmonary artery.