Surgery – Means for introducing or removing material from body for... – Material introduced into and removed from body through...
Reexamination Certificate
1998-05-13
2001-07-24
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Material introduced into and removed from body through...
C604S043000
Reexamination Certificate
active
06264627
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a catheter, to be inserted into and guided by a blood vessel, comprising an elongate catheter body, having a distal end and a proximal end, and an outer essentially cylindrical surface, limiting a wall structure, enclosing at least two channels, and to a method for detection of substances in a heart. Further it relates to a method for detection of metabolic changes in a heart.
BACKGROUND OF THE INVENTION
The human heart represents a major organ with respect to morbidity and mortality among the population. In spite of increased knowledge and treatment of cardiovascular disorders myocardial infarction and coronary artery disease still represent major causes of death. Acute myocardial infarction was the primary cause of 25,023 deaths during 1992 in Sweden.
Microdialysis is used to monitor the interstitial fluid in various body organs with respect to local metabolic changes. The technique is now also experimentally applied in humans for measurements in adipose tissue (H. Rosdahl, U. Ungerstedt and J. Henriksson, “Microdialysis in human skeletal muscle and adipose tissue at low flow rates is possible if dextran-70 is added to prevent loss of perfusion fluid”, Acta Physiol Scand, 1997, 159, pp 261-262), muscle (Rosdahl et al, as above, D. G. Maggs, W. P. Borg and R. S. Sherwin, “Microdialysis techniques in the study of brain and skeletal muscle”, Diabetologia, 1997, 40: pp 75-82, Springer-Verlag and P. A. Jansson, J. Fowelin, U. Smith, and P. Lönnroth, 1988, “Characterization by microdialysis of intercellular glucose levels in subcutaneous tissue in humans”, Am J Physiol 255, E218-E220.) and brain (Maggs el al, as above and R. Kanthan, A. Shuaib, G. Goplen and H. Miyashita, “A new method of in-vivo microdialysis of the human brain”, Journal of Neuroscience Methods 60 (1995) 151-155). Routine use of microdialysis in clinical settings is, however, not yet established. Traditionally microdialysis catheters are inserted into the tissue and after an equilibration period, measurements of metabolic changes within the local tissue area can be made.
In U.S. Pat. No. 4,694,832, a dialysis probe is disclosed, which is primarily used for insertion into biological tissues, for example brain tissue. In such applications, the probe is located in the tissue through operation. It can also be inserted into a blood vessel or into tissue in the same manner as a canula and is then provided with a pointed, cutting edge. Consequently it is not suitable to be inserted into and guided by a blood vessel. Also the design of the dialysis chamber makes it unsuitable for insertion into and guidance by a blood vessel, since it is too fragile.
When admitted to a cardiac intensive care unit, patients with chest pain are routinely monitored by ECG and intermittent peripheral venous plasma markers (ASAT, ALAT, CK/CK-B, troponin-T and troponin-I ) for detection of cardiac damage. Regretfully though, the observed metabolic changes are usually detected late in the onset of myocardial infarction and angina pectoris. These markers are monitored in peripheral venous plasma by repeated blood sampling, and the response time is usually several hours. This halters the active treatment and intervention of ongoing myocardial ischaemia. Furthermore, a number of patients subjected to coronary surgery with CABG (coronary artery bypass grafting) or valve replacement have cardiac failure or associated diseases which increase the risk of the operation. These patients are post-operatively hemodynamically monitored in the intensive care unit but appropriate means of rapidly detecting metabolic disturbances in the heart are still lacking.
A continuous, rapid and selective monitoring of metabolic disturbance of the heart during ischaemia without repeated blood sampling would greatly enhance the possibilities of active intervention to prevent the development of myocardial infarction with non-reversible damage of the heart in patients admitted to cardiac intensive care units as well as in patients undergoing cardiac surgery.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a device which can be used for achieving an accurate and rapid response to the presence of certain substances in the blood of a blood vessel, and is robust, simple to insert, and has a simple construction.
It is also an object of the present invention to provide an efficient device which can be used for accurate and rapid detection of substances in the coronary sinus related to metabolic changes in the heart.
Through the arrangement of a microdialysis chamber, a device is achieved, which can be used when measuring substances in blood, without the need of taking blood samples.
Through the arrangement of a microdialysis chamber, further, the device is achieved which has a short response time when used for measuring/monitoring substances in blood.
Through the specific design of the channels and the microdialysis chamber, a catheter, which is simple to manufacture is achieved.
REFERENCES:
patent: 4694832 (1987-09-01), Ungerstedt
patent: 5106365 (1992-04-01), Hernandez
patent: 5191900 (1993-03-01), Mishra
patent: 5353792 (1994-10-01), Liibbers et al.
patent: 5441481 (1995-08-01), Mishra et al.
patent: 5607390 (1997-03-01), Patsalos et al.
patent: 5735832 (1998-04-01), Karlsson
Huxtable “Federation Proceedings vol. 39, No. 9 Jul. 1980” pp. 2685-2690.
Thorac. cardiovasc. Surgeon 41 (1993) pp. 93-100.
European Heart Journal (1987) 8, 206-207.
Journal of Neuroscience Methods 60 (1995) 151-155.
Microdialysis of Human Tissue in Vivo pp. E218-E220.
D.G. Maggs et al. Brain and Skeletal Muscle Microdialysis pp. S75-S82.
Acra Physiol Scand 1997, 159, 261-262.
Swedish Article, Stockholm i Apr. 1995.
AFA Arbetsmarknadens Försakringsaktiebolag 24 pages.
Journal of Cerebral Blood Flow and Metabolism vol. 5, No. 3, 1985.
Franco-Cereceda Anders
Liska Jan
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