Devices and methods for control of blood pressure

Abstract

Apparatus and methods are described including an implantable device having first and second longitudinal ends, the device having a length of less than 80 mm when the device is unconstrained. The device includes struts arranged such that, when the device is unconstrained, along a continuous portion of the device having a length that is at least 5 mm, a maximum inter-strut distance defined by any set of two adjacent struts is more than 1.5 times as great as a maximum inter-strut distance defined by any set of two adjacent struts within longitudinal portions of the device within 3 mm of the longitudinal ends of the device. Other applications are also described.

What is claimed is: 
     
         1 . Apparatus comprising:
 an implantable device having first and second longitudinal ends, the device having a length of less than 80 mm when the device is unconstrained;   the device comprising struts, arranged such that, when the device is unconstrained, along a continuous portion of the device having a length that is at least 5 mm, a maximum inter-strut distance defined by any set of two adjacent struts is more than 1.5 times as great as a maximum inter-strut distance defined by any set of two adjacent struts within longitudinal portions of the device within 3 mm of the longitudinal ends of the device.   
     
     
         2 . The apparatus according to  claim 1 , wherein the device is configured to lower blood pressure of a patient, by being implanted proximate to a baroreceptor within an artery of the subject. 
     
     
         3 . The apparatus according to  claim 2 , wherein the continuous portion of the device comprises a portion of a region of the device that defines no struts, the region having a non-circular shape. 
     
     
         4 . The apparatus according to  claim 2 , wherein the continuous portion of the device comprises a portion of a region of the device that defines no struts, a center of the region being disposed asymmetrically with respect to a length of the device. 
     
     
         5 . The apparatus according to  claim 2 , wherein along the continuous portion of the device, the maximum inter-strut distance defined by any set of two adjacent struts is more than 3 times as great as the maximum inter-strut distance defined by any set of two adjacent struts within longitudinal portions of the device within 3 mm of the longitudinal ends of the device. 
     
     
         6 . The apparatus according to  claim 2 , wherein the device has a length of less than 50 mm. 
     
     
         7 . The apparatus according to  claim 1 , wherein the device has a spring constant of less than 2 N/mm. 
     
     
         8 . The apparatus according to  claim 7 , wherein the device has a spring constant of less than 1.5 N/mm. 
     
     
         9 . The apparatus according to  claim 1 , wherein along the continuous portion of the device, the maximum inter-strut distance defines an arc of more than 30 degrees around a longitudinal axis of the device. 
     
     
         10 . The apparatus according to  claim 9 , wherein along the continuous portion of the device, the maximum inter-strut distance defines an arc of more than 60 degrees around the longitudinal axis of the device. 
     
     
         11 . The apparatus according to  claim 1 , wherein within the longitudinal portions of the device within 3 mm of the longitudinal ends of the device the struts define angles therebetween, wherein within the continuous portion the struts define angles therebetween, and wherein a minimum angle defined by the struts within the longitudinal portions of the device within 3 mm of the longitudinal ends of the device is greater than a minimum angle defined by the struts within the continuous portion. 
     
     
         12 . The apparatus according to  claim 11 , wherein a ratio of the minimum angle defined by the struts within the longitudinal portions of the device within 3 mm of the longitudinal ends of the device to the minimum angle defined by the struts within the continuous portion is greater than 1.25. 
     
     
         13 . The apparatus according to  claim 12 , wherein the ratio of the minimum angle defined by the struts within the longitudinal portions of the device within 3 mm of the longitudinal ends of the device to the minimum angle defined by the struts within the continuous portion is greater than 2. 
     
     
         14 . Apparatus comprising:
 an implantable device that is shaped to define struts arranged such that, when the device is unconstrained, along a continuous portion of the device having a length that is at least 5 mm, a maximum inter-strut distance defined by any set of two adjacent struts is more than 5 mm,   the implantable device having a length of less than 80 mm when the device is unconstrained,   the implantable device, at any location along the length of the device, defining a ratio of a perimeter of a cross-section of the device at the location to the cross-sectional area defined by the struts of the device at the longitudinal location, and   the implantable device defining a maximum value of said ratio,
 the ratio being more than 80 percent of the maximum value of the ratio along more than 80 percent of a length of the device. 
   
     
     
         15 . The apparatus according to  claim 14 , wherein the device is configured to lower blood pressure of a patient, by being implanted proximate to a baroreceptor within an artery of the subject. 
     
     
         16 . The apparatus according to  claim 15 , wherein the continuous portion of the device comprises a portion of a region of the device that defines no struts, the region having a non-circular shape. 
     
     
         17 . The apparatus according to  claim 15 , wherein the continuous portion of the device comprises a portion of a region of the device that defines no struts, a center of the region being disposed asymmetrically with respect to a length of the device. 
     
     
         18 . The apparatus according to  claim 15 , wherein the device has a length of less than 50 mm. 
     
     
         19 . The apparatus according to  claim 14 , wherein the device has a spring constant of less than 2 N/mm. 
     
     
         20 . The apparatus according to  claim 19 , wherein the device has a spring constant of less than 1.5 N/mm. 
     
     
         21 . The apparatus according to  claim 14 , wherein along the continuous portion of the device, the maximum inter-strut distance defines an arc of more than 30 degrees around a longitudinal axis of the device. 
     
     
         22 . The apparatus according to  claim 21 , wherein along the continuous portion of the device, the maximum inter-strut distance defines an arc of more than 60 degrees around the longitudinal axis of the device. 
     
     
         23 . The apparatus according to  claim 14 , wherein along the continuous portion of the device, the maximum inter-strut distance defined by any set of two adjacent struts is more than 1.5 times as great as a maximum inter-strut distance defined by any set of two adjacent struts within longitudinal portions of the device within 3 mm of longitudinal ends of the device. 
     
     
         24 . The apparatus according to  claim 23 , wherein along the continuous portion of the device, the maximum inter-strut distance defined by any set of two adjacent struts is more than 3 times as great as the maximum inter-strut distance defined by any set of two adjacent struts within the longitudinal portions of the device within 3 mm of longitudinal ends of the device. 
     
     
         25 . Apparatus comprising:
 an implantable device that is shaped to define struts, the device being shaped such that over a continuous portion of the device having a length that is at least 5 mm, the device defines at least one circumferential region in which no struts are disposed, the region defining an arc of at least 30 degrees around a longitudinal axis of the device,   a cross-sectional shape of the device at the region being shaped to define a major axis and a minor axis, at least when the device is in a non-constrained state thereof,   a major axis of the cross-sectional shape being parallel to a plane defined by the region in which no struts are disposed, and a minor axis of the cross-sectional shape being perpendicular to the plane.   
     
     
         26 . The apparatus according to  claim 25 , wherein the device is configured to lower blood pressure of a patient, by being implanted proximate to a baroreceptor within an artery of the subject. 
     
     
         27 . The apparatus according to  claim 26 , wherein the region defines an arc of at least 60 degrees around the longitudinal axis of the device.