Background: The NO--cGMP system plays a key role in the regulation of sinusoidal tonus and liver blood flow with phosphodiesterase-5 (PDE-5) terminating the dilatory action of cGMP. We, therefore, investigated the effects of PDE-5 inhibitors on hepatic and systemic hemodynamics in rats.
Methods: Hemodynamic parameters were monitored for 60 min. after intravenous injection of sildenafil and vardenafil [1, 10 and 100 microg/kg (sil1, sil10, sil100, var1, var10, var100)] in anesthetized rats.
Results: Cardiac output and heart rate remained constant. After a short dip, mean arterial blood pressure again increased. Systemic vascular resistance transiently decreased slightly. Changes in hepatic hemodynamic parameters started after few minutes and continued for at least 60 min. Portal (var10 -31%, sil10 -34%) and hepatic arterial resistance (var10 -30%, sil10 -32%) decreased significantly (p < 0.05). At the same time portal venous (var10 +29%, sil10 +24%), hepatic arterial (var10 +34%, sil10 +48%), and hepatic parenchymal blood flow (var10 +15%, sil10 +15%) increased significantly (p < 0.05). The fractional liver blood flow (total liver flow/cardiac output) increased significantly (var10 26%, sil10 23%). Portal pressure remained constant or tended to decrease. 10 microg/kg was the most effective dose for both PDE-5 inhibitors.
Conclusion: Low doses of phosphodiesterase-5 inhibitors have distinct effects on hepatic hemodynamic parameters. Their therapeutic use in portal hypertension should therefore be evaluated.
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http://dx.doi.org/10.1186/1471-230X-9-69 | DOI Listing |
J Cereb Blood Flow Metab
January 2025
Neuronal Mass Dynamics Lab, Department of Biomedical Engineering, Florida International, University, Miami, FL, USA.
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University of Maryland School of Medicine, Department of Diagnostic Radiology and Nuclear Medicine, Division of Vascular and Interventional Radiology, Baltimore, MD, USA.
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December 2023
Department of Pediatric Cardiovascular Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
To improve the suboptimal outcomes of the cutback technique for cardiac total anomalous pulmonary venous return, we devised a novel modification for this conventional method that consists of an L-shaped incision of the roof of the coronary sinus into the pulmonary venous confluence, followed by turning over the flap and anchoring it to the endocardium of the left atrium. Our modification provides a large, oval communication between the pulmonary vein confluence and the left atrium and resultant smooth drainage of the pulmonary venous blood, which may prevent turbulent blood flow and the subsequent development of intimal hyperplasia.
View Article and Find Full Text PDFAnn Thorac Surg Short Rep
December 2023
Department of Pediatric Cardiac Surgery, Stanford University, Palo Alto, California.
The Norwood procedure with the right ventricle-to-pulmonary artery (RV-PA) conduit has been the standard procedure for hypoplastic left heart syndrome. However, postoperative management can be challenging related to finding the correct balance between pulmonary and systemic blood flow. One can use hemostatic clips on the RV-PA conduit to temporarily restrict pulmonary blood flow.
View Article and Find Full Text PDFAnn Thorac Surg Short Rep
December 2024
Duke University Medical Center, Durham, North Carolina.
Background: Direct mechanical ventricular actuation (DMVA) with the Anstadt cup is effective for non-blood-contacting biventricular support. Pneumatic regulation of a silicone device augments ventricular pump function. Vacuum attachment facilitates diastolic augmentation critical for biventricular support.
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