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Main Pulmonary Artery (main + pulmonary_artery)
Selected AbstractsA case of pulmonary arteritis with stenosis of the main pulmonary arteries with positive myeloperoxidase-antineutrophil cytoplasmic autoantibodiesRESPIROLOGY, Issue 4 2000Hiroyuki Nakayama A 53-year-old woman was referred to our hospital with the main symptoms of productive cough, fever and exertional dyspnoea. Chest X-ray revealed enlargement of the left hilar shadow and cavitary infiltration in the right upper lobe. 99mTechnetium-macroaggregated albumin (99mTc-MAA) perfusion scintigram showed complete hypoperfusion through the entire right lung. A pulmonary angiogram revealed stenotic lesions in the right and left main pulmonary arteries. Right cardiac catheterization showed an elevated right ventricular systolic pressure. There was no evidence of systemic arterial lesions nor vasculitis. The patient was positive for myeloperoxidase (MPO)antineutrophil cytoplasmic autoantibodies (ANCA) (168 EU). The Mycobacterium avium complex sputum culture was positive. The pulmonary stenotic lesions were surgically resected. The resected pulmonary arterial lesions were pathologically diagnosed as non-specific vasculitis. The cavitary lesion disappeared 6 months after the surgery. Two years after the surgery, although the MPO-ANCA level had decreased to 12 EU, stenosis of the pulmonary arteries reappeared. It is suggested that the patient became positive for MPO-ANCA in association with the Mycobacterium avium complex infection, and that the presence of MPO-ANCA may not be related to the development of pulmonary stenosis of the main pulmonary arteries. [source] Attenuated endothelin-1 mRNA expression with endothelin-1 receptor blockade during hypoxaemia and reoxygenation in newborn pigletsACTA PAEDIATRICA, Issue 6 2000S Medbø We investigated the cause of decreased plasma endothelin-1 (ET-1) during hypoxaemia and reoxygenation in newborn piglets subjected to simultaneous blocking of the ET-1 receptors. Changes in plasma ET-1 and prepro-ET-1 mRNA expression in the main pulmonary artery and the left lower lobe in the lung were studied in 1-2-d-old piglets. Ten minutes prior to hypoxaemia, the hypoxaemia group (n = 10) was given saline, two groups (both n = 9) were given 1 and 5 mg/kg i.v. SB 217242 (an ET-1 receptor antagonist). Two groups served as normoxic controls, with and without SB 217242 5 mg/kg i.v. Hypoxaemia was induced by ventilating with 8% O2 until base excess was 20mmol/l or mean arterial blood pressure was < 20mmHg. Reoxygenation was performed for 2h with room air. During hypoxaemia, plasma ET-1 decreased in the hypoxaemia group, remained unchanged in the 1-mg group and increased in the 5-mg group. At the end of reoxygenation, plasma ET-1 was above baseline in the 1-mg and 5-mg groups. In the pulmonary artery, the hypoxaemia group showed 2- to 5-fold higher prepro-ET-1 mRNA expression compared to all the other groups (p < 0.05). There were trends for higher prepro-ET-1 mRNA expression in pulmonary tissue in the hypoxaemia group compared to the two receptor-blocking groups (p < 0.07). Conclusions: We conclude that hypoxaemia and reoxygenation increase prepro-ET-1 mRNA expression in the pulmonary artery in newborn piglets. These observations suggest that the half-life of ET-1 is decreased during hypoxaemia and reoxygenation in newborn piglets. [source] Balloon Debanding the Pulmonary Artery: In Vitro Studies and Early Clinical ExperienceCONGENITAL HEART DISEASE, Issue 4 2009Gareth J. Morgan MPhil ABSTRACT Despite increasing corrective procedures for children with congenital heart disease, there remains a place for surgical banding of the main pulmonary artery (PA). In the vast majority of cases, these bands eventually need to be removed. We examined three cases of percutaneous disruption of PA bands using balloon catheters at our institution. We also performed an in vitro study of PA band disruption mechanism and disruption pressure. Our in vitro study suggested a predictable burst pressure for PA bands over the range of diameters routinely used in pediatric practice. Of three patients who underwent interventional debanding, two patients had successful disruption of their PA bands with no reintervention at 19 months and 23 months follow up. Balloon disruption of surgical PA bands may offer a less invasive alternative to surgical band removal. In vitro analysis suggests that the burst pressure required and mechanism of disruption are predictable. [source] Late Presentation of Pulmonary Valve Stenosis Confirmed by Cardiovascular Magnetic ResonanceCONGENITAL HEART DISEASE, Issue 3 2008Didier Locca MD ABSTRACT We describe the case of a 70-year-old man who presented with increasing exertional dyspnea. He was found to have an ejection systolic murmur and evidence of right ventricular outflow tract obstruction, with a peak velocity of 4.5 m/s recorded by transthoracic Doppler echocardiography. Cardiovascular magnetic resonance showed right ventricular hypertrophy, pulmonary valve stenosis, peak recorded velocity 4.2 m/s, with thickened pulmonary valve leaflets of reduced mobility, and poststenotic dilatation of the main pulmonary artery. The case illustrates that severe pulmonary valve stenosis can present late in life and that cardiovascular magnetic resonance can be useful in clarifying nature and level of right ventricular outflow tract obstruction in an adult. [source] Reliability of Intraoperative Transesophageal Echocardiography During Tetralogy of Fallot RepairECHOCARDIOGRAPHY, Issue 4 2000JAMES J. JOYCE M.D. There is limited information available concerning the accuracy of intraoperative transesophageal echocardiography (TEE) in predicting the extent of residual abnormalities after recovery from surgical repair of tetralogy of Fallot. Therefore, we investigated differences between the results of final postbypass TEE and those of postrecovery (mean, 6 days after surgery) transthoracic echocardiography in a total of 28 consecutive pediatric patients who underwent repair of tetralogy of Fallot with biplane or multiplane TEE. Both postbypass and postrecovery echocardiographic examinations included measurements of the right ventricle (RV)-main pulmonary artery (PA) and the main PA-branch PA peak instantaneous gradients, the degree of pulmonary valvar insufficiency, and color Doppler interrogation of the ventricular septum for residual defects. The RV-main PA gradient did not change significantly: 15 ± 13 vs 18 ± 14 mmHg (postbypass versus postrecovery, mean ± SD). None of the patients had a decrease of , 10 mmHg; and only one patient had an increase of ,: 15 mmHg. There also was no change in the degree of pulmonary insufficiency (3.0 ±1.2 versus 3.1 ± 1.1, using a scale of 0 to 4). Only one of the seven very small (, 2 mm) residual ventricular septal defects was not discovered during postbypass TEE. However, postrecovery transthoracic echocardiography detected significant branch PA stenosis (peak gradient, , 15 mmHg) in five patients (18%) that was not detected during postbypass TEE (P < 0.03). Of the branch PA stenoses that were not detected during TEE, four were left and one was right. Conclusions: Postbypass TEE after tetralogy of Fallot repair reliably predicts residual postrecovery hemodynamic abnormalities, except for branch PA stenosis. [source] Estimation of pulse wave velocity in main pulmonary artery with phase contrast MRI: Preliminary investigationJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2006Hsu-Hsia Peng MS Abstract Purpose To assess the feasibility and reproducibility of a noninvasive MRI method to measure pulse wave velocity (PWV) in the main pulmonary artery (MPA). Materials and Methods A total of 17 subjects without history of pulmonary diseases (38.2 ± 18.4 years) participated in this study. Series of MR velocity maps of the MPA were acquired at 2 cm above the pulmonary valves using a two-dimensional phase-contrast sequence. Effective temporal resolution was 11 msec after interleaving two dynamic series with different values of electrocardiograph (ECG) trigger delay. PWV was derived as the rate of MPA flow variations per unit change in MPA cross-sectional area, during early systole. Seven healthy subjects underwent three repetitive examinations to investigate intrascan and interscan reproducibility. Results Flow vs. area was highly linear in the MPA during early systole, with Pearson's coefficients ranging from 0.982 to 0.999, rendering derivation of PWV with little difficulty. Average value of PWV in MPA was 1.96 ± 0.27 m/second, in good agreement with literature values measured using invasive means. The percentage intra- and interscan differences were 5.46% and ,10.86%, respectively. Conclusion Phase-contrast MRI to noninvasively measure PWV in the MPA is feasible with good reproducibility. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc. [source] Management of a cadaveric orthotopic liver transplantation in a pediatric patient with complex congenital heart diseasePEDIATRIC ANESTHESIA, Issue 6 2006DENNIS E. FEIERMAN MD PhD Summary Pediatric orthotopic liver transplantations (OLT) are commonly performed nowadays. Two primary reasons for OLT in children are complications from either extrahepatic biliary atresia (EHBA) or inborn errors of metabolism. However, congenital liver disease may be associated with significant other congenital abnormalities. We present a case of a successful OLT in a pediatric patient with a history of EHBA, situs inversus, and complex congenital heart disease. The cardiac anomalies include dextrocardia, absence of the atrial septum (single atrium), single atrioventricular valve (a-v canal), and an incomplete ventricular septum. Prior surgery include a Kasai procedure for EHBA, banding of the proximal main pulmonary artery, and Broviac catheter placement. We present the anesthesia concerns and management for this complicated case. [source] Cardiac air transit following venous air embolism and right ventricular air aspiration,ANAESTHESIA, Issue 7 2009S. T. Schäfer Summary Using intra-cardiac echocardiography in anaesthetised swine we tested the hypotheses that embolised air (i) passes immediately through the right atrium into the ventricle; (ii) persists in the right ventricle for a long time; (iii) is detectable for longer within the right ventricle or main pulmonary artery than the right atrium, and (iv) right ventricular aspiration recovers more air than right atrial aspiration. Following intravenous injection of different air volumes the air appeared in the right atrium in a mean (95% CI) of 3 s (2.5,3.5 s) and almost simultaneously in the right ventricle after 5 s (3.9,6.0 s), but air persisted for longer in the right ventricle (420 s; (367,473 s)) and pulmonary artery (541 s; (475,606 s)) than in the right atrium (404 s (353,457 s)), particularly with larger air volumes and in the semi-upright position. More air was recovered via a right ventricular catheter than an atrial catheter (52% vs 25%, p < 0.01). [source] Development of the Baylor Gyro Permanently Implantable Centrifugal Blood Pump as a Biventricular Assist DeviceARTIFICIAL ORGANS, Issue 9 2001Kenji Nonaka Abstract: The Baylor Gyro permanently implantable centrifugal blood pump (Gyro PI pump) has been under development since 1995 at Baylor College of Medicine. Excellent results were achieved as a left ventricular assist device (LVAD) with survival up to 284 days. Based on these results, we are now focusing on the development of a biventricular assist device (BVAD) system, which requires 2 pumps to be implanted simultaneously in the preperitoneal space. Our hypothesis was that the Gyro PI pump would be an appropriate device for an implantable BVAD system. The Gyro PI 700 pump is fabricated from titanium alloy and has a 25 ml priming volume, pump weight of 204 g, height of 45 mm, and pump diameter of 65 mm. This pump can provide 5 L/min against 100 mm Hg at 2,000 rpm. In this study, 6 half-Dexter healthy calves have been used as the experimental model. The right pump was applied between the infundibular of the right ventricle and the main pulmonary artery. The left pump was applied between the apex of the left ventricle and the thoracic descending aorta. As for anticoagulation, heparin was administered at the first postoperative week and then converted to warfarin sodium from the second week after surgery. Both pump flow rates were controlled maintaining a pulmonary arterial flow of less than 160 ml/kg/min for the sake of avoidance of pulmonary congestion. Blood sampling was done to assess visceral organ function, and the data regarding pump performance were collected. After encountering the endpoint, which the study could not keep for any reasons, necropsy and histopathological examinations were performed. The first 2 cases were terminated within 1 week. Deterioration of the pump flow due to suction phenomenon was recognized in both cases. To avoid the suction phenomenon, a flexible conduit attached on the inlet conduit was designed and implanted. After using the flexible inflow conduit, the required power and the rotational speed were reduced. Furthermore, the suction phenomenon was not observed except for 1 case. There was no deterioration regarding visceral organ function, and pulmonary function was maintained within normal range except for 1 case. Even though the experimental animal survived up to 45 days with the flexible inflow conduit, an increase in power consumption due to thrombus formation behind the impeller became a problem. Lower rotational speed, which was probably produced by the effectiveness of the flexible inflow conduit, was speculated to be one of the reasons. And the minimum range of rotational speed was 1,950 rpm in these 6 BVAD cases and the previous 3 cases of LVAD. In conclusion, 6 cases of BVAD implantation were performed as in vivo animal studies and were observed up to 45 days. The flexible inflow conduit was applied in 4 of 6 cases, and it was effective in avoiding a suction phenomenon. The proper rotational speed of the Gyro PI 700 pump was detected from the viewpoint of antithrombogenicity, which is more than 1,950 rpm. [source] Development of the NEDO Implantable Ventricular Assist Device with Gyro Centrifugal PumpARTIFICIAL ORGANS, Issue 6 2000Masaharu Yoshikawa Abstract: The Gyro centrifugal pump, PI (permanently implantable) series, is being developed as a totally implantable artificial heart. Our final goal is to establish a "functional TAH," a totally implantable biventricular assist system (BiVAS) with centrifugal pumps. A plastic prototype pump, Gyro PI 601, was evaluated through in vitro and in vivo studies as a single ventricular assist device (VAD). Based upon these results, the pump head material was converted to a titanium alloy, and the actuator was modified. These titanium Gyro pumps, PI 700 series, also were subjected to in vitro and in vivo studies. The Gyro PI 601 and PI 700 series have the same inner dimensions and characteristics, such as the eccentric inlet port, double pivot bearing system, secondary vane, and magnet coupling system; however, the material of the PI 700 is different from the PI 601. The Gyro PI series is driven by the Vienna DC brushless motor actuator. The inlet cannula of the right ventricular assist system (RVAS) specially made for this system consists of 2 parts: a hat-shaped silicone tip biolized with gelatin and an angled wire reinforced tube made of polyvinylchloride. The pump-actuator package was implanted into 8 calves in the preperitoneal space, bypassing from the left ventricle apex to the descending aorta for the left ventricular assist system (LVAS) and bypassing the right ventricle to the main pulmonary artery for the RVAS. According to the PI 601 feasibility protocol, 2 LVAS cases were terminated after 2 weeks, and 1 LVAS case and 1 RVAS were terminated after 1 month. The PI 700 series was implanted into 4 cases: 3 LVAS cases survived for a long term, 2 of them over 200 days (72,283 days), and 1 RVAS case survived for 1 month and was terminated according to the protocol for a short-term antithrombogenic screening and system feasibility study. Regarding power consumption, the plastic pump cases demonstrated from 6.2 to 12.1 W as LVAS and 7.3 W as RVAS, the titanium pump cases showed from 10.4 to 14.2 W as LVAS and 15.8 W as RVAS. All cases exhibited low hemolysis. The renal function and the liver function were maintained normally in all cases throughout these experimental periods. In the 2 RVAS cases, pulmonary function was normally maintained. No calves demonstrated thromboembolic signs or symptoms throughout the experiments except Case 1 with the plastic pump. However, in the plastic pump cases, bilateral renal infarction was suspected in 2 cases during necropsy whereas no abnormal findings were revealed in the titanium pump cases. There were also no blood clots inside the PI 700 series. As for the 601, the explanted pumps demonstrated slight thrombus formations at the top and bottom pivots except in 1 case. The Gyro PI series, especially the PI 700 series, demonstrated superior performance, biocompatibility, antithrombogenicity and low hemolysis. Also, the durability of the actuator was demonstrated. Based on these results, this titanium centrifugal pump is suitable as an implantable LVAS and RVAS. It is likely that the Gyro PI series is a feasible component of the BiVAS functional TAH. [source] Thrombin activation of proteinase-activated receptor 1 potentiates the myofilament Ca2+ sensitivity and induces vasoconstriction in porcine pulmonary arteriesBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2010Jun Maki Background and purpose:, Thrombus formation is commonly associated with pulmonary arterial hypertension (PAH). Thrombin may thus play an important role in the pathogenesis and pathophysiology of PAH. Hence, we investigated the contractile effects of thrombin and its mechanism in pulmonary artery. Experimental approach:, The cytosolic Ca2+ concentrations ([Ca2+]i), 20 kDa myosin light chain (MLC20) phosphorylation and tension development were evaluated using the isolated porcine pulmonary artery. Key results:, Thrombin induced a sustained contraction in endothelium-denuded strips obtained from different sites of a pulmonary artery, ranging from the main pulmonary artery to the intrapulmonary artery. In the presence of endothelium, thrombin induced a transient relaxation. The contractile effect of thrombin was abolished by either a protease inhibitor or a proteinase-activated receptor 1 (PAR1) antagonist, while it was mimicked by PAR1 -activating peptide (PAR1AP), but not PAR4AP. The thrombin-induced contraction was associated with a small elevation of [Ca2+]i and an increase in MLC20 phosphorylation. Thrombin and PAR1AP induced a greater increase in tension for a given [Ca2+]i elevation than that obtained with high K+ -depolarization. They also induced a contraction at a fixed Ca2+ concentration in ,-toxin-permeabilized preparations. Conclusions and implications:, The present study revealed a unique property of the pulmonary artery. In contrast to normal arteries of the systemic circulation, thrombin induces a sustained contraction in the normal pulmonary artery, by activating PAR1 and thereby increasing the sensitivity of the myofilament to Ca2+. This responsiveness of the pulmonary artery to thrombin may therefore contribute to the pathogenesis and pathophysiology of PAH. [source] | ||||||||||||||||||||||