AS REPORTED by various authors,'-! surgical closure of a patent ductus arteriosus with pulmonary hypertension presents a considerable operative risk. In fact, in these cases the patent ductus may constitute a safety valve for the hypertensive lesser circulation and its surgical closure may therefore suddenly increase the pulmonary hypertension with resultant acute right ventricular strain.3 The...

The cardiovascular system, comprised of the heart and blood vessels, is the first functional organ formed during embryogenesis in higher vertebrates. In the mouse, the heart and first vessels become functional as early as 8 days following fertilization, while in humans the cardiovascular system forms after approximately 3 weeks of development. Cardiovascular function is essential to the surviva...

Aortopulmonary (AP) window is exactly a rare natural anomaly that represents roughly 0.2 and 0.5 of all heart abnormalities. It consists communication between the aorta pulmonary roadway or its branches. occurs due to abnormal development heart’s major blood vessels during early fetal growth. In utmost cases, this disfigurement by chance, with no clear reason. This condition can do on own other...

The mechanical properties of the walls of blood vessels have an important influence on the flow of blood and passage of pulse waves along them. Though a certain amount of information is available concerning the mechanical properties of the aorta and its main branches (Burton, 1954), we have been unable to find any observations on the pulmonary circulation. Hence, in view of the increasing inter...

A new method for relating regional intravascular resistance to pulmonary arterial, capillary, and venous pressure and volume was used to evaluate local differences of reactivity in the pulmonary blood vessels in the isolated lung lobe of the dog. Intravascular infusion of isoproterenol caused active dilatation of pulmonary arteries and veins. Capillary conductance (1/resistance) and volume incr...

The inducible isoform of nitric-oxide synthase (iNOS) is highly expressed after induction of endotoxemia and contributes to vascular hypocontractility in endotoxemia. Circulating levels of histamine are elevated in animal models of sepsis and in patients with septic shock. This study assessed whether the vascular effects of histamine play a significant role in the pathophysiology of endotoxemic...

Blood viscosity, haematocrit and plasma protein concentrations were determined simultaneously in five different vessels of the systemic and pulmonary circulations, before and immediately after cardiopulmonary bypass and again after surgery. There was a reduction in all these measurements after bypass and a lesser reduction one day after operation. At any one stage, however, values in the pulmon...

Neurofibromatosis has been known to involve blood vessels throughout the body. Pulmonary involvement with interstitial fibrosing alveolitis has been described but no case of pulmonary vascular involvement has been reported to date. A 51 year old patient with cutaneous neurofibromatosis is described who presented with severe pulmonary hypertension and radiographic, scintigraphic, and angiographi...

When O2 availability is reduced unavoidably, as it is at high altitude, a potential mechanism to improve O2 delivery to tissues is an increase in blood flow. Nitric oxide (NO) regulates blood vessel diameter and can influence blood flow. This field study of intrapopulation variation at high altitude tested the hypothesis that the level of exhaled NO (a summary measure of pulmonary synthesis, co...