Surgery – Cardiac augmentation
Patent
1992-02-20
1994-12-13
Kamm, William E.
Surgery
Cardiac augmentation
623 3, A61M 112
Patent
active
053725735
DESCRIPTION:
BRIEF SUMMARY
This invention relates to techniques and apparatus for improving blood flow in vivo. The invention finds application in both clinical and veterinary practice.
Numerous problems arise from localised impedance to blood flow in both humans and non-human animals. For example, arterial damage, e.g. atherosclerosis, in the leg often requires complex surgery in which, typically, the long saphenous vein is used as a graft to by-pass the non-functional arterial region. Also, cirrhosis of the liver, which may result from alcohol abuse in the western world but which is widespread in the third world as a result of vital hepatitis, results in an impedance to blood flow from the hepatic portal vein into the liver. This results in blood by-passing the liver through portal vein tributaries which feed into the stomach. This results in bleeding from the stomach wall (i.e. oesophageal varices).
The conventional treatment for this condition takes several forms: the blood pressure may be relieved by surgically forming a porto-systemic shunt such as a porto-caval shunt, in which the portal vein is connected to the vena cava; or sclerotherapy may be used, in which the portal vein tributaries are closed off by an appropriate injection. Other conventional treatments are oesophageal transaction, in which the portal vein tributaries are closed off by appropriate sutures; and liver transplantation. These various treatments have various advantages and disadvantages and, in some circumstances, may be of limited value. Sclerotherapy and oesophageal transection may not be effective over a long period of time because the portal pressure (i.e. the blood pressure in the portal vein) is not reduced and often causes a recurrence of bleeding, and a porto-caval shunt leads to most of the products absorbed by the gastro-intestinal tract passing directly into the general blood circulation, instead of travelling first to the liver where extensive metabolic processes, in particular detoxification processes, take place. This decrease in blood flow through the liver reduces the effectiveness of this organ, particularly in its detoxifying capacity. This in turn can lead to serious side effects such as hepatic encephalopathy.
It will be appreciated from the above examples that standard treatment for a localised impedance to blood flow is to provide some means whereby blood can by-pass the obstruction, thereby removing the localised hypertension, or to replace the diseased segment as in liver transplantation.
The present invention proceeds from the realisation that this standard approach is flawed. In many clinical or veterinary conditions demonstrating localised blood flow impedance, we believe that superior results may be achieved if instead of providing a surgical by-pass or other conventional treatment, means are adopted whereby blood flow is assisted through the area of impedance. This will generally result in localised hypertension, but the effects of this will not be felt systemically. Replacing the diseased vessel containing the vascular imbalance (liver transplantation) is not a practical proposition on a large scale because of the high cost of this procedure and because of the limited availability of donors.
According to one aspect of the present invention, there is provided a method of improving the flow of blood through a region of increased impedance, which comprises assisting blood flow in the said region by means of a pump placed in or around a blood vessel supplying blood to said area, and acting to pump blood in the required direction.
The pump may be, for example, an Archimedes screw which acts directly on the blood flowing within the vessel undergoing treatment, or it may be a peristaltic-type pump which acts on the outside of the vessel.
The invention will be described further with reference to treatment of the portal vein or hepatic pedicle (free edge of the lesser ormentum) to overcome problems arising from cirrhosis of the liver, although it is to be understood that the invention is of general applicability and is not restricted t
REFERENCES:
patent: 3518033 (1970-06-01), Anderson
patent: 3885251 (1975-05-01), Pedroso
patent: 4014318 (1977-03-01), Dockum et al.
patent: 4794910 (1989-01-01), Mushika
British Technology Group Limited
Kamm William E.
Schaetzle Kennedy J.
LandOfFree
Blood flow does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Blood flow, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Blood flow will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1190276