Patent Application
20110230821
The invention belongs to broad field of urgent and intensive medicine and relates to system for providing of effective perfusion of vital organs during cardio-circulatory arrest in an in-hospital and in out-of-hospital environment.
The following is a tabulation of some prior art that presently appears relevant:
Acute cardio-circulatory arrest is the most frequent cause of sudden death. Emergency treatment includes artificial ventilation and external cardiac massage with chest compressions. Treatment of cardio-circulatory arrest has not changed since 50 years. Electrical cardiac instability is effectively treated with defibrillations while pulmonary function is replaced by mechanical ventilation after placement of tracheal tube. Mechanical chest compression is aimed at maintaining perfusion of vital organs. Low success rate of resuscitation measures is mainly attributed to ineffectiveness of chest compressions to provide minimum of needed perfusion. The pressure differences between aorta and right atrium as the principal determinant of existing circulation, is negligible during chest compressions. Numerous versions of mechanical apparatus for external cardiac compression have emerged: U.S. Pat. No. 7,131,953 to Scherman (2006) shows a resuscitation device for automatic compression of a victim's chest using a compression belt operable attached to a platform on which a victim rests. U.S. Pat. No. 5,399,148 to Waide (1995) shows an external cardiac massage device comprising a pressure source and depressor means for adjustable cardiac compression. Numerous versions of apparatus for internal cardiac massage also emerged: W.O. Pat. No. 94/03228 to Zadini (1994) shows an apparatus comprising an expandable member placed inside the chest adjacent the heart whereby during inflation of the expandable member the heart is compressed between the thoracic spine and the member itself; W.O Pat. No. 98/05289 to Fogarty (1998) shows a minimal invasive direct cardiac massage device comprising an inflatable bladder introduced through the intercostals space and placed between the sternum and the heart.
None of these numerous versions of mechanical apparatus for external or internal cardiac compression has substantially improved the effective blood flow during cardio-circulatory arrest.
In specialized hospitals, sporadically, systems for artificial mechanical circulation are used: accessing a reservoir of blood (cardiac chamber), withdrawal of the blood into a pump and returning of the blood into the circulation with pump energy. U.S. Pat. No. 5,190,528 to Fonger (1993) shows system of cannulas for accessing the left atrium by so called transseptal route: Under fluoroscopy a cannula is placed from the groin vein transseptally into the left atrium and the oxygenated blood from the left atrium is transported with a roller pump through the second cannula placed through the groin artery into aorta. Installation of this system requires cardiac catheterization team and equipment. U.S. Pat. No. 7,494,477 to Rakhorst (2009) shows a pulsatile catheter that is introduced through the aorta retrograde across the aortic valve and placed into the left ventricle. The blood is drained from the left ventricle and pumped back into the aorta through the same catheter. The pulsatile 25Fr catheter with an unidirectional valve situated inside the catheter lumen between distal opening within the left ventricle and side-opening situated in the aorta, and the extracorporeal displacement chamber with a volume of 60 ml provides a flow of up to 2.9 lit/min. (Mihaylov D. et al. Evaluation of the optimal driving mode during left ventricular assist with pulsatile catheter pump in calves. Artificial organs 1999; 23:1117-1122.). This system is aimed at assisting a failing heart and cannot replace the pumping function in case of arrest. Also its implementation is complex requiring surgically created access to aorta or a great artery. DE Souza C F. et al describe in their paper (DE Souza C F. et al. Percutaneous mechanical Assistance for The Failing Heart. J Interven Cardiol 2010; 23:195-202) today's most usable systems for nonsurgical percutaneous mechanical circulation. Intraaortic balloon pump is useful only as a support to failing heart, it is not useful during cardiac arrest. Hemopump™=turbine pump placed on the tip of the access cannula introduced through a groin artery retrograde into the left ventricle wherefrom it transports the blood to aorta. This system is aimed at supporting a failing heart although sporadically it has been used during cardiac arrest too. For its placement a fluoroscopy is needed, vascular access is a problem, pumping blood volume capacity is low and it produces aortic pressure of up to 50 mmHg. The percutaneous left ventricular assist device “Tandem Heart” is a left atrial to femoral artery bypass having a 21 Fr left atrial cannula for withdrawing of the oxygenated blood from left atrium which is then injected by means of a centrifugal pump into the femoral artery establishing the bypass.
This system provides a flow of up to 4 L/min. Also this system is aimed at assisting a failing ventricle and not for replacing an arrested pumping function.
Cardio-pulmonary support system comprising access cannula for accessing large central systemic veins wherefrom the blood is withdrawn into a console with oxygenators (apparatus which replaces the lung) after which the blood is pumped back into the aorta through the cannula placed through a groin artery. A miniaturized portable version of cardio-pulmonary support is available (Arlt M, et al. First experience with a new miniaturized life support system for mobile percutaneous cardiopulmonary bypass. Resuscitation 2008; 77: 345-350). This system is expensive, complex, and requires a specialized trained team for its utilization.
Also for its implementation in average 30 minutes are needed (Chen S I, Ko W J, Lin F Y. Insertion of Percutaneous ECMO Cannula. Am J Emerg Med; 2000; 18:184-185).
Advantages of cardio-pulmonary systems are large blood volume pumping capacity of up to 6 Lit/min, disadvantages of this system are—the lung and the left heart remain without circulation—they are not decompressed; often blood transfusions are needed, for installation of this system a well trained team is needed and time needed for its implementation, which time is not available in urgent situations during cardiac arrest. All described systems for percutaneous mechanical circulation require access through the large veins and/or arteries.
A heart chamber is filled with blood and it has larger volume than any groin artery or vein and thus it can be easier punctured especially during cardiac arrest. Percutaneous transthoracic puncture of the left ventricle has been utilized for diagnostic purposes in patients with implanted metallic heart valves in aortic and mitral position. Complication rates were acceptable (Walters D L. et al. Catheter Cardiovascular Intery 2003; 58:539-44: Transthoracic left ventricular puncture for assessment of patients with aortic and mitral valve prosthesis: Massachusetts General hospital experience 1989-2000). Percutaneous transthoracic access has been used recently for catheter based procedures like closure of paravalvular leaks (Webb J, The shortest Way to the Heart. Catheterization and Cardiovascular Interventions 2008; 71:920; Turgut T, Deeb M, Moscucci M, Left ventricular apical puncture: A procedure surviving well into the new millennium. Catheterization and Cardiovascular Interventions 2000; 49:68-73). U.S. Pat. No. 7,524,277 to Wang (2009) shows a system that utilizes a single transapical entry site into the left ventricle for placement of a single cannula with a common access to left ventricle and to aorta. This system obviates the need for two access sites since blood is withdrawn from the left ventricle through the larger outer part of cannula and injected back into the aorta through the smaller inner cannula with the tip of smaller cannula situated in the aorta. Blood aspiration through the outer part of cannula and blood injection through the central part of cannula by external driving apparatus needs a large diameter of the single entry site and a safety regulation adjusted to available blood volume. Also, this system for assisting a heart is complex for an emergency need during a cardiac arrest.
Access to heart chambers by thoracoscopic methods is described in US Pat. No. 3,952,742 to Taylor (1976): a transthoracic cannula is equipped with penetration needle and with two axially spaced balloons for stabilization and sealing purposes; this resuscitation transthoracic cannula is aimed at providing electrical support to an arrested heart as well as at providing an application of needed medication during resuscitation. This system however provides no circulatory support.
U.S. Pat. No. 6,406,422 B1 to Landsberg (2003) shows a system for assistance of failing heart (assist device) that utilizes a single cannula for drainage out of heart chamber and for return of blood into the chamber of a failing heart (single cannula ventricular assist apparatus). This system is aimed at supporting a failing heart chamber (usually left ventricle) in such a way that it uses the computer regulated withdrawal of the small amount of blood out of the left ventricle during the diastole and also computer regulated return of the small amount of the blood back into the left ventricle during ventricular systole. This method is used to augment the existing stroke volume of a failing heart.
The blood volume added with this system during ventricular native contraction is small—about 30 ml per systole. This system is not suitable for replacement of heart pump function during a cardiac arrest.
Based on the prior art analysis there is obviously need for a system, method, device that could enable an effective perfusion of vital structures (brain and heart muscle) during cardiac arrest. Such a device should have following characteristics: it should be implementable within a short period of time (e.g. within 3 minutes); it should be applicable at any place were a victim could be located; it should be of small size in order to fit into a first aid case and thus affordable to any emergency first aid medicine professionals in hospital as well as in out of hospital environment.
The aim of this invention is to provide a system of rapid establishment of circulatory flow during a cardio-circulatory arrest in an in-hospital and in an out-of-hospital environment, a system simple to use and less expensive in order to be affordable to majority of professionals involved in resuscitation activities.
In accordance with one embodiment, a device system for invasive resuscitation of arrested circulation includes a large bore cannula for accessing an arrested cardiac chamber and a large volume syringe attached to a frame. The syringe includes a mechanism for power facilitated manual driving. The access cannula includes means for introduction by over the wire introducing technique. In one embodiment the cannula is equipped with two balloons for sealing and stable anchorage within the intracorporeal passageway. The large volume syringe and access cannula are interconnected by a large bore 3-way stopcock. In one embodiment, after transthoracic placement of the access cannula into the arrested left ventricle, the cannula is connected to the syringe and the oxygenated blood is manually aspirated from the left ventricle and from the left atrium and rapidly injected back through the same cannula into the left ventricle. The system utilizes the naturally existing two unidirectional check valves within the arrested left heart: mitral inflow check valve, and aortic outflow check valve.
Application of negative aspiration pressure opens the inflow check valve and closes the outflow check valve allowing drainage of the whole left heart.
Aspiration volume=left ventricular volume+left atrial volume.
During a rapid injection of large blood and/or fluid volume into the arrested left ventricle the pressure inside the left ventricle rises and closes the inflow check mitral valve. Since the injecting volume exceeds the volume capacity of the arrested left ventricle the blood surplus is injected across the outflow check valve into aorta.
Injecting stroke volume=total injecting volume−volume capacity of the arrested left ventricle.
Assuming a left atrial volume of 80 ml, a left ventricular volume of 100 ml the maximal aspirating volume would be 180 ml. Assuming an injecting volume of 180 ml by known left ventricular volume capacity of 100 ml the injecting stroke volume would be 80 ml.
The device in accordance with described embodiment can be used as an alternative to prolonged chest compression or as a last resort measure after failure of traditional resuscitation attempts.
If a professional aid has exhausted all available measures to restore spontaneous circulation in a victim, this device assembly should be used:
puncturing of the left ventricular apex with a vascular needle through the fifth intercostals space at midclavicular line. The puncture does not need any imaging guidance; aspirating a small amount of red colored blood indicates that the left ventricle is punctured (during a resuscitation the oxygen saturation within the left heart is >90% and within the right heart is <30% which gives a visible color differences in blood samples—a blood sample from left heart is red colored while a blood sample from the right heart is dark colored “Ward K R. Barbee W, Ivatury R R. Monitoring techniques during CPR in “Cardiopulmonary Resuscitation 2000: Chapter 28:480-482. Editors Ornato J P, Peberdy M A, Humana Press Inc. Totowa, N.J. 07512”);
injecting of medication against clotting (Heparin) through the puncturing needle into the punctured heart chamber;
placing of a J guiding wire 240 through the needle; after removal of the puncture needle the cannula assembly (
after advancement of the cannula into the heart chamber the smaller non compliant balloon 218 is inflated by fluid injection through the channel 222 and the cannula is retracted back over the dilator 230 until a resistance is felt which indicates that balloon 218 is contacting the inner wall of the heart chamber (this will indicate the appropriate good placement of the cannula); dilator 230 is removed together with guide wire 240; the stopcock 208 is closed; then the larger outer compliant balloon 214 is inflated by injecting fluid through the channel 216 this will provide sealing and stabilization of the cannula within the intracoerporeal passageway; the syringe pump assembly 100′ is connected to the access cannula 200 by the stopcock 208; stopcock 208 is opened and the pump assembly is actuated double handed by pulling the plunger 144′ upwards which provides aspiration of the oxygenated blood from the left ventricle and from the left atrium and even from pulmonary veins; next stopcock 208 is closed and directed to enable removal of air bubbles if any existing; stopcock 208 is directed to free the flow from the syringe 140′ into the access cannula 200; the aspirated blood volume is vigorously injected back through the cannula 200 into the left ventricle (
The system is immobilized by holding the foot on the pedal during operation.
The manual driving enables blood withdrawal adjusted to the available blood volume within the left heart avoiding tubing collapse and or aspiration of surrounding tissue and/or aspiration of extracorporeal air alongside the passageway of the access cannula. The right heart functions like a passive conduit having two unidirectional valves which will be open when the central venous pressure is higher than the pressure within lung vessels, as in Fontan's circulation
(The “Fontan's circulation” refers to the configuration where the single ventricle pumps blood returning from the lungs to the body, and the blood returning from the body travels to the lungs by direct blood vessel connections without a pumping chamber).
It is important to increase the volume within the central venous system which can be done e.g. by passive rising of victim's legs.
Should there be not enough aspirating blood volume, additional fluid volume could be aspirated from the fluid infusion attached to the sidearm of stopcock 208.
Also additional medication against clotting (Heparin) is added through the side-arm of stop-cock 208.
Alternatively, the access cannula can be introduced with a splittable introducing sheath 250 (
After restoration of spontaneous circulation pump assembly 100′ can be disconnected leaving the access cannula 200 in place with infusion attached to the cannula. After termination of the support the cardiac access site could be closed with a myocardial free wall occluder or surgically.
Puncture of subclavian/axillary artery with a vascular needle; advancement of the long guiding wire 326 through the needle, removal of the needle; advancement of the transthoracic cannula assembly with pigtail catheter 320, and dilator 310 over the wire, retrograde through the aortic valve until the cannula is situated within the left ventricle; removal of wire 326 and removal of introducing dilator 310 with pigtail catheter 320, and connection of the cannula 300 to pump syringe assembly 100′; manual actuation of the system as described before.
This alternative embodiment can be used mostly in an in-hospital environment where there are some tools for guiding the procedural activities like ultrasound or fluoroscopy.
In one embodiment a small tubing is incorporated into upper distal part of syringe. This vent tube for air removal 141 arises from the opening 145 at the top of syringe 140. Tube 141 has a small 3-way stopcock 143 for air vent tube at its distal end. Tube 141 enables removal of possible air bubbles from the syringe. Distal arcuate fastener 103 is fixed to top plate 102. There are 2 holes 105h on arcuate fastener 103 (
Two rods 105 extent form fastener 107. Syringe 140 as seen in
Arcuate fasteners 103 and 107, rod 105, screw 105s, and the frame parts 102, 104, 106, 108, can be made of light weighed metal or of a firm plastic. Muff 147 should be made of transparent plastic in order to enable visual control of presence of possible air bubbles or presence of possible blood clots within the syringe. The base of frame 106 and vertical arms 104 may have removable connection to top plate 102 which could reduce the portable size of the assembly. Assembly 100 may be provided as a sterile compact unit ready for use, so that no time is needed for set up.
In cases were the resuscitation attempts with utilization of this concept with single access to the left ventricle became prolonged or ineffective, installation of an additional parallel system into the right ventricle could be implemented as shown in
Two transthoracic access cannulas 200″ are inserted, and connected to double syringe pump assemblies 100″. Both levers 122 are inter connected with the removable connector for common grip 125 to common grip 124″ which enables simultaneous actuation of both parallel installed assemblies providing a replacement of the total heart pumping function. Also, installation of two systems parallel for the right and left heart with individually regulated actuation is possible after removal of grip connector 125.
In accordance with described additional embodiment, after installation of the cannula 200 into the left ventricle and connection to pump assembly 100 the same approach is applied for installation of additional parallel situated system 100 and 200 into the right ventricle (
In cases were the resuscitation attempts with utilization of this concept with single access to the left ventricle became prolonged or ineffective, installation of an additional parallel system into the right ventricle could be implemented as shown in
Two transvascular access cannulas 300 are connected to double syringe pump assemblies 100″.
A subclavian/axillary artery and subclavian vein are punctured (
In accordance with additional embodiment (
This alternative embodiment utilizes an installation through a groin vein by transseptal access through the interatrial septum from the right atrium to the left atrium. This alternative embodiment can be used to treat accidents in a catheterization laboratory environment where there are tools for guiding the procedural activities like ultrasound and fluoroscopy. Also this alternative embodiment can be used in cardiac surgery environment. In some situations after cardiac surgery the patient cannot be disconnected from cardiopulmonary bypass apparatus used during operation. The cannula 300 can be placed from a groin vein transseptally into the left ventricle by direct visual control and the patient can be disconnected from cardiopulmonary bypass. In unstable situations, cannula 300 can be left in place as long as needed. Cannula 300 placed transseptally through a groin vein can be removed without any additional surgical procedure like re-sternotomy or a surgical closure of arterial entry site.
Advantage of such an access is the fact that there is no compromise of arterial circulation. Also in case of cardiac arrest in patients after sternotomy chest compression is problematic.
(
This alternative embodiment can be used in an in hospital environment where there are tools for guiding the procedural activities like ultrasound and fluoroscopy.
One transvascular cannula 300, and one transthoracic cannula 200 are connected to double syringe pump assembly 100″: having an actuation with manual grips interconnected with removable connector for common grip 125.
In accordance with described embodiment, the transthoracic cannula 200 is placed into the left ventricle through the left ventricular apex and a transvascular cannula 300 is placed into the right ventricle through the subclavian vein; the cannulas are connected to double syringe pump assembly 100″; manual actuation of assembly 100″ by common grip 124″ the total heart pump function can be replaced. This embodiment can be used in cases where a prolonged resuscitation is needed.
This embodiment can be used even in an out-of-hospital environment since it can be implemented with a guidance of a portable ultrasound.
The access cannula 300 is placed into the left ventricle and it is attached to syringe pump assembly 100 for providing perfusion in case of cardiac arrest. A motor is attached to the syringe plunger by an removable connector of motor 500 to plunger of the syringe.
In accordance with this embodiment the manual device for cardio-circulatory resuscitation is combined with a motorized (electro motorized or pneumatic) actuation. In case of prolonged resuscitation a fatigue of an aid can be compensated by utilization of a battery powered motorized mechanism which can be connected to the syringe plunger by a removable connector 500.
The device described can be used as an alternative to prolonged chest compression or as a last resort measure after failure of today's standard resuscitation attempts. There are large number of victims who are too healthy to be left to die after unsuccessful resuscitation attempt with chest compressions.
If a professional aid has provided an advanced life support to a victim including mechanical ventilation through a tracheal tube, defibrillation attempts, chest compressions, medication injected, and if there is no response, instead of giving up, he takes the described manual device for cardio circulatory resuscitation out of his first aid case and gives the victim an additional chance:
Puncture of the left ventricular apex directly through the chest wall with a vascular needle through the fifth intercostals space at midclavicular line (it takes <1 minute). The puncture does not need any apparatus depended guidance-aspirating a small amount of red colored blood indicates that the left ventricle is punctured; injection of Heparin through the puncturing needle into the left ventricle; placement of a J guide wire 240 through the needle; after removal of puncture needle the transthoracic cannula 200 with introducing dilator 230 (
After termination of resuscitation the victim can be transported to an institution where the cardiac access site can be closed with a myocardial free wall occluder or surgically.
In an environment with available apparatus-depended guidance like fluoroscopy and or ultrasound the alternative embodiment of this device can be used:
The transvascular cannula assembly (
Treatment of cardio circulatory arrest has not substantially changed since 50 years. With tracheal intubation, respiratory function is completely replaced with mechanical ventilation while chest compressions are aimed at maintaining perfusion of vital organs. Electrical instability is effectively treated by defibrillations. Today's advanced life support results in return of spontaneous circulation in about 10% of out-of-hospital victims and in 20-30% of in-hospital victims. Only a small number of these primary successfully resuscitated victims survive and even smaller is the number of victims who survive without significant neurological sequels. The dismal low resuscitation success rate is mainly attributable to failure of chest compressions to provide sufficient circulatory flow. Emergency widespread use of surgical cardiopulmonary bypass is not practicable. Percutaneous circulatory assistance like percutaneous left atrial to aorta or left ventricular to aorta bypass, or a miniaturized percutaneous cardiopulmonary bypass (ECMO) are complex, expensive and time consuming.
Non-invasive measures for providing some ventilation during resuscitation attempts had not been sufficiently effective in the past.
Artificial ventilation became effective only after introduction of the procedure with placement of a tubus directly into respiratory system to activate the mechanical function of arrested lung.
Non invasive measures, like chest compressions, for providing some circulation during resuscitation attempts have not been sufficiently effective in the past 50 years.
Artificial circulation will become effective after placement of a tubus directly into heart chamber to activate the mechanical pump function of arrested heart.
The device described in this application could provide sufficient supply of oxygenated blood to vital organs during cardio circulatory arrest. It could be applied in hospital as well as on the field. The device is manually driven independent of any energy power sources, and it could be brought into function rapidly by a professional aid trained for this procedure.
In an emergency situation, such is cardiac arrest, mortality may exceed 90%. Because of large numbers of victims of this condition even small increases in survival could save many lives. Even if the described manual device for cardio circulatory resuscitation would only reduce mortality from 90% to 80%—that would translate into a potential saving of more than 100 000 lives per year in the United States and Europe (some 450 000 people die each year from sudden cardiac arrest in the United States and some 700 000 people die from sudden cardiac arrest each year in Europe—“International Liaison Committee on Resuscitation. Part 2. Adult basic life support. Resuscitation 2005; 67(2/3):187-201”).
From the description above, a number of advantages of some embodiments of my device for cardio circulatory resuscitation become evident:
the device is small, portable, light weighted (<3 kg);
it is simple for manufacturing, relatively less expensive and thus it can be affordable to all economical and social environments;
it can be provided in a ready for use configuration with an instant set up time;
it can be implemented within couple of minutes;
it effects perpetual contractions and distensions of the cavity of an arrested heart chamber by hydraulically transmitted energy which is generated by external manual driving of the syringe pump assembly;
it forces a dead heart to open and close its valves and to contract and distend its wall without spending its own intrinsic energy and without any electrical activity;
it provides effective perfusion with oxygenated blood to vital organs;
it provides heart and pulmonary decompression;
it is independent of any energy power sources;
it can be implemented in-hospital and on the field without any apparatus-depended guidance;
it can be up graded for replacement of the total pumping function of left and right heart by installing double syringe assembly 100″ and double cannulas (
Application of this device is not limited to resuscitation of victims with cardio-circulatory arrest.
There is possibility to use this device to maintain perfusion of organs in a victim without any chances of survival. This might be the case in a situation where the today's medicine is trying to save victim's organ for donation in those victims who do have a written consent for organ donation in case of inevitable fatal outcome.
Despite the increase in the number of organ transplants there is shortfall of organs suitable for donation. A large number of victims who die from trauma or accidents with organs suitable for transplants could have their organs salvaged. The chances to save the organs of these potential donors in difficult environments are very low due to the fact that there is no system that provides organ perfusion on the field and an organ explantation on the field is not possible. The device presented in this application could be implemented to provide perfusion until a victim with expected fatal outcome is transported to a facility where organ explantation could be performed. The utilization of this device is primarily oriented to human medicine, but the same indications for use are valid for veterinary medicine, i.e. the use of this device is valid for all mammalians.
Although the description above contains many specificities, these should not be construed as limiting the scope of the embodiments but as merely providing illustrations of some of several embodiments.
For example, the manual pumping facilitation can be achieved with a spring mechanism. The syringe plunger 144 is functionally connected to a power spring which would be compressed during manual aspiration phase in which way a considerable potential spring energy could be accumulated and so accumulated energy could reduce energy needed during vigorous injections (not shown).
The frame into which syringe 140 is situated may have different configuration. In one embodiment top plate 102 of the frame may have a removable fastener that could enable a fastening of the syringe to a platform on which a victim rests. In such a configuration (not shown) base of frame 106 and vertical arms 104 would not be needed which would further reduce the size and the weight of the portable device.
The described manually driven pump assembly with a large bore syringe as the pump, is only one of possible embodiments.
In an another embodiment (not shown) the pump may be construed as a compressible bag. Such a bag may be manually compressed for injecting the blood and may be expanded either manually or with an equipped spring system. The volume capacity of such a bag may be appropriately large. Such a bag may be produced from an elastic medical polymer like polyurethane with heparin coated inner surface.
The transthoracic cannula may be equipped with two introducing dilators (not shown); one of which is smaller to be advanced over the guiding wire, and the larger one which is placed over the smaller dilator. The smaller dilator, larger dilator placed over the smaller one, and cannula 200 placed over the larger dilator can be introduced percutaneously as a unit. In this way passage of the assembly through the chest wall might be safer especially in obese victims.
Also, the braided parts of access cannulas (202, or 302) may be manufactured from a memory metal. In this way the braided part of cannula may be expandable after introduction. Such a cannula may have a smaller fixed profile within the passageway through the entry site and an expandable lumen within a blood vessel and within a heart chamber which could increase the flow capacity of such a configuration. Such cannulas are already commercially available, but some configurations could be modified for use as a part of the device described. This version could be useful especially for transvascular cannula 300.
Cannula 300 may have extension of the wires of the braided part of wall.
These wires could make non traumatic arms (not shown) radial expanded distal to end opening 306 of cannula which could provide stable anchorage and prevent dislodgement of the cannula during repeated vigorous injections maneuvers.
The wires could have folding position during introduction and expanding position after placement into heart chamber. Thus the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than by the examples given.
This application claims the benefit of provisional patent application Ser. No. 61/340,764, filed 2010 Mar. 20 by the present inventor.
| Number | Date | Country | |
|---|---|---|---|
| 61340764 | Mar 2010 | US |
