Archive for the ‘Lung Transplantation’ Category


In addition, areas of SLTX arteries were larger than those of the native pulmonary arteries, both in peak systole and end diastole. Thus, increased flow to the LTX compared with the native lung is accompanied by both higher flow velocities and larger vessel area, but without changes in DI.
One drawback of our study might be the fact that volunteers differed from patients with regard to gender and age distribution. However, Davidson and Fee have shown that there are no differences in pulmonary hemodynamics and cardiac output between men and women. In the same study, the authors nevertheless found an increase of pulmonary artery pressure and resistance with aging. Still, these differences were only significant when comparing a population >60 years with much younger individuals and the overall values were within the normal range. (more…)

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  • Pulmonary and Aortic Blood Flow Measurements in Normal Subjects and Patients After Single Lung Transplantation: OutcomeHowever, significantly higher RI values in the patient’s native pulmonary arteries compared with the SLTX arteries possibly reflect the elevated resistance in the vascular bed of the diseased lung. One of the drawbacks of this study is the lack of comparison of the RI to invasively assessed values of different PVR and pressure. It has been demonstrated in animals that the RI as measured by duplex Doppler sonography in renal arteries reflects renal vascular resistance. However, good correlation was demonstrated between the RI and the amount of diastolic backflow from the native pulmonary arteries itat on canadian pharmacy levitra. Thus, both parameters might reflect increased PVR. Although future studies on the value of RI measurements with invasive hemodynamic parameter correlation are mandatory, we believe that the RI might provide important noninvasive information about pulmonary hemodynamics. (more…)

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  • With regard to differential lung perfusion, in this study 5.1 ±1.3 L/min of right cardiac output is ejected into the transplanted lung and only 1.1 ±0.8 L/min into the native lung (SLTX to native lung=81 to 19%), whereas volunteers showed almost equal perfusion of both vascular beds (right to left lung=55 to 45%), as has been shown by others. The ratio of blood flow to the transplanted and the native lungs in this study is similar to that reported for perfusion scintigraphy by others, but higher than that reported for VEC-MRI (approximately three to one) by Mohiaddin et al, probably again due to different preoperative pulmonary pressures and vascular resistances in the study populations. However, radionuclide scanning provides only semiquantitative data and does not give absolute values of blood flow. (more…)

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  • Pulmonary and Aortic Blood Flow Measurements in Normal Subjects and Patients After Single Lung Transplantation: DiscussionVEC-MRI provides a powerful noninvasive tool for assessing blood flow velocities and volumes in the proximal pulmonary artery system as well as in the ascending and descending aorta and its major branches.
    In this study, the flow patterns observed in the AAO, MPA, RPA, and LPA of volunteers were similar to those reported in the literature. Canadian family pharmacy online fully The slight amount of early diastolic retrograde blood flow in the AAO has been reported to be due to coronary filling. However, no retrograde flow was observed in the MPA of volunteers and flow profiles of the RPA and LPA were almost identical. These observations are sharply contrasted by the findings in our patient group. Whereas flow profiles in the AAO of patients were not significantly different from those of volunteers, blood flow in the MPA demonstrated a retrograde peak in early diastole in six of nine patients, indicating mild to midgrade pulmonary insufficiency. (more…)

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  • Distensibility Index: Results are shown in Figure 5 and Table 2. DI of the AAO and MPA was not significantly different either in or between volunteers and patients and there was also no significant difference in the DI of RPA and LPA in volunteers. Compared with patients, DI of the RPA in the control group was significantly higher than DI of LTX and native lung arteries (p<0.05), whereas DI of the LPA was not significantly different from the DI of the patient’s pulmonary vessels; however, overall DI showed higher values in the control group. Changes in vessel area of RPA and LPA as well as LTX and native pulmonary artery over the cardiac cycle in one volunteer and one patient are demonstrated in Figure 6. (more…)

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  • Pulmonary and Aortic Blood Flow Measurements in Normal Subjects and Patients After Single Lung Transplantation: ResultsIn SLTX patients, blood flow patterns in the AAO did not differ significantly from those obtained in volunteers. In the MPA, a slight amount of retrograde flow was demonstrated during early diastole in six of nine patients. Buy proventil fully Flow profiles in the transplant pulmonary artery and the native lung pulmonary artery were significantly different from those assessed in the RPA and LPA of volunteers. The transplant lung artery showed a large systolic peak, followed by a second small flow peak in early diastole and no retrograde blood flow. In the native lung arteries, a small systolic peak and retrograde blood flow during the whole diastole was demonstrated in all cases (Fig 3). (more…)

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  • In the flow phantom study, correlations between absolute values of true and MRI-derived velocities and flow volumes were assessed by means of linear regression analysis. Correlations between left and right cardiac output both in volunteers and in patients and correlations of the sum of LPA and RPA flow with MPA flow, and net retrograde flow in the native lung pulmonary artery with RI were assessed by linear regression analysis itat on buy birth control. Wilcoxon’s signed-ranked test was used to compare differences in peak average systolic velocities, flow volumes, RI, and DI. These comparisons were done in volunteers and in patients, in right and left, and in native and transplanted lung pulmonary arteries, and tested for statistical significance. A p value <0.05 was considered statistically significant. Results are expressed as the mean of each group ±1 SD. (more…)

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  • Pulmonary and Aortic Blood Flow Measurements in Normal Subjects and Patients After Single Lung Transplantation: In Vitro StudyIn Vitro Study
    Accuracy of the VEC-MRI sequence was evaluated using a flow phantom consisting of a straight glass tube with an inner diameter of 1 cm. This glass tube was aligned along the z-axis of the magnetic field. Continuous flow of water was created by a roller pump with velocities ranging from 10 to 80 cm/s. Canadian pharmacy mall True flow was measured using a scaled collecting bowl and a stop watch. An untriggered VEC-MRI sequence using scan parameters listed above was employed to obtain images perpendicular to the glass tube and thus perpendicular to the flow direction. The velocity encoding value was set to 100 cm/s and a body wrap-around receiving coil was used. (more…)

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