Staged implantation of ventricular assist devices

Abstract

An implantation regime for a ventricular assist device (VAD) comprising implanting a first VAD ( 13 ) intended for short term use for a predetermined period of time and then determining whether the heart can operate without further assistance after this period of time. A second VAD ( 30 ) intended for long term use may then be implanted if necessary. Also disclosed are percutaneous leads ( 40 ) that have surface treatments ( 45, 47 ) to enable tissue ingrowth in certain areas and prevent tissue ingrowth in other areas, and an embolisation device ( 21, 22 ) carrying a coagulating material ( 27 ) for sealing an implanted cannula ( 15, 16 ) between the use of the first and second VADs.

1 . A method of mechanically assisting a heart to pump blood; said method comprising releasably, sealingly connecting a first ventricular assist device via a first cannula and a second cannula so as to at least assist said heart to pump said blood during a first predetermined period of time, ascertaining if mechanical assistance continues to be required and, if so, substituting a second ventricular assist device at the end of said first predetermined period of time and wherein said first and said second ventricular assist devices are implantable into a patient's body and are both pumping devices and wherein said first ventricular assist device is adapted for short term use and wherein said second ventricular assist device is adapted for long term use.  
     
     
         2 . The method of  claim 1  wherein said cannulae are capable of being reused for connection of said first ventricular assist device or said second ventricular assist device.  
     
     
         3 . The method of  claim 2  wherein said first ventricular assist device incorporates short term life features which renders said first ventricular assist device suited to operation over a short life span.  
     
     
         4 . The method of  claim 3  wherein said short term life features include use of plastic material in one or more of the pump casing and pump rotor of said first ventricular assist device.  
     
     
         5 . The method according to any one of the preceding claims wherein said cannulae are capable of being either permanently or temporarily scaled so as to allow permanent implantation of the cannulae without need to be connected to either said first ventricular assist device or said second ventricular assist device.  
     
     
         6 . The method of  claim 5  wherein said first cannula includes an end for connection to the aorta and a distal end connecting to either an inlet of a first ventricular assist device or an inlet of a second ventricular assist device, in use; and said second cannula includes an end for connection to a ventricle and a distal end connecting to either an outlet of said first ventricular assist device or an outlet of said second ventricular assist device, in use.  
     
     
         7 . The method of  claim 6  wherein said second ventricular assist device is adapted for substitution of said first ventricular assist device following a first predetermined period of operation of said first ventricular assist device.  
     
     
         8 . The method of  claim 7  wherein the first cannula or the second cannula are adapted to receive the insertion of an embolisation device.  
     
     
         9 . The method of  claim 8  wherein said first ventricular assist device is made by an injection moulding process.  
     
     
         10 . The method of  claim 8  wherein said first ventricular assist device is made by a vacuum casting process.  
     
     
         11 . The method of  claim 8  wherein said first ventricular assist device includes a pump rotor made from a plastic material.  
     
     
         12 . The method of  claim 8  wherein said second ventricular assist device includes a pump casing made from a metallic material.  
     
     
         13 . The method of  claim 8  wherein said second ventricular assist device includes a pump casing made from a ceramic material.  
     
     
         14 . The method of  claim 8  wherein said second ventricular assist device includes a rotor made from ceramic material.  
     
     
         15 . The method of  claim 8  wherein said short term use is a period of time between 3 to 6 months.  
     
     
         16 . The method of  claim 8  wherein said long term use is a period of time between 1 to 10 years.  
     
     
         17 . The method of  claim 5  wherein said method includes a test procedure to determine whether heart can operate without the further assistance of said first ventricular assist device.  
     
     
         18 . The method of  claim 17  wherein said test procedure includes a monitoring operation of said heart over said predetermined period of time.  
     
     
         19 . The method of either claims  1  or  5  wherein said method includes the use of an insulated percutaneous lead for supplying power to either a first or second ventricular assist device.  
     
     
         20 . The method of  claim 19  wherein a portion of an outer surface of said lead prevents incorporation of surrounding tissue.  
     
     
         21 . The method of  claim 21  wherein a portion of an outer surface of said lead allows incorporation of surrounding tissue.  
     
     
         22 . The method of  claim 19  wherein said surface comprises one surface texture.  
     
     
         23 . The method of  claim 19  wherein said lead includes at least two surface textures on predetermined portions of the surface of said lead, wherein a first surface texture allows incorporation of said lead into tissue and wherein a surface texture prevents incorporation of said lead into tissue.  
     
     
         24 . The method of  claim 23  wherein an amount of tissue incorporation of said lead can be varied to suit needs by arrangement of the surface textures.  
     
     
         25 . The method of  claim 24  wherein each of said surface textures comprises at least one application of a surface treatment to said lead.  
     
     
         26 . The method of  claim 25  wherein said surface texture is modified as to the degree to which said incorporation of portions of said lead into tissue surrounding said lead is promoted therein.  
     
     
         27 . The method of  claim 25  wherein said surface treatment includes an application of velour to the surface of said lead.  
     
     
         28 . The method of  claim 25  wherein said first surface texture has a labyrinth arrangement.  
     
     
         29 . The method of  claim 25  wherein said incorporation of portions of said lead into tissue surrounding is promoted controlled by selection of depth and shape of said surface textures.  
     
     
         30 . The method of  claim 29  wherein the portion allowing incorporation may extend to a length sufficient to anchor said lead to a site where said lead exits the body or proximal to said site.  
     
     
         31 . The method of  claim 30  wherein the second surface texture prevents incorporation so as to facilitate easy removal of the lead.  
     
     
         32 . The method of  claim 5  wherein the said method includes an embolisation device for insertably sealing a cannula, wherein said embolisation device comprises a scaling cap at a first end, a carrier surface at a second end and an elongate stem adapted to be inserted within the cannula.  
     
     
         33 . The method of  claim 32  wherein the carrier surface is adapted to carry a coagulating material.  
     
     
         34 . The method of  claim 33  wherein said embolisation device seals a cannula at a scaling point close to the heart.  
     
     
         35 . The method of  claim 34  wherein said sealing cap is adapted to be sealingly connected to a corresponding connector on the cannula.  
     
     
         36 . The method of  claim 35  wherein the elongated stem is of a length so that when the device is entirely inserted within said cannula, the carrier surface is positioned to deliver coagulating material to the sealing point.  
     
     
         37 . The method of  claim 36  wherein said embolisation device is connected removably and releasably to the cannula, in use.  
     
     
         38 . An embolisation device for insertably sealing a cannula, wherein said embolisation device comprises a sealing cap at a first end, a carrier surface at a second end; wherein the carrier surface is adapted to carry a coagulating material and induces an embolism at a position proximal to said second end and an elongate stem adapted to be inserted within the cannula.  
     
     
         39 . The embolisation device of  claim 38  wherein said embolisation device seals a cannula at a sealing point proximal to a heart of a patient, in use.  
     
     
         40 . The emolisation device of  claim 39  wherein said scaling cap is adapted to be sealingly connected to a corresponding connector of the cannula.  
     
     
         41 . The emolisation device of  claim 40  wherein the elongated stem is of a length so that when the device is entirely inserted within said cannula, the carrier surface is positioned to deliver coagulating material to a sealing point at some point proximal to a heart of a patient, in use.  
     
     
         42 . The embolisation device of  claim 40  wherein said scaling point is sufficiently close to the heart so that there is no requirement to remove the cannula from the body.  
     
     
         43 . The embolisation device of  claim 40  wherein said embolisation device is connected removably and releasably to the cannula, in use.