Devices and methods for control of blood pressure

Abstract

Apparatus and methods are described, including identifying a subject as suffering from hypertension. In response to the identifying (a) a radius of curvature of a first set of at least three regions of an arterial wall of the subject is increased at a given longitudinal location, while (b) allowing the first set of regions of the arterial wall to pulsate. A device is implanted inside the artery at the longitudinal location such that the device applies pressure to the arterial wall at a second set of at least three regions of the artery, but does not contact the first set of regions, the first set regions and the second set of regions alternating with each other. Other embodiments are also described.

1 - 51 . (canceled) 
     
     
         52 . A method of treating a disease related to hypertension of a subject, comprising:
 identifying the subject as suffering from hypertension; and   in response thereto:   stretching an aorta of the subject in a vicinity of a baroreceptor, between a plurality of separate regions of the aorta, by applying forces to the plurality of regions of the aorta, by placing an element inside the subject's aorta, the element defining aorta-contacting regions that apply the forces to the regions,   the placing of the element inside the subject's aorta being such that, during at least a portion of a cardiac cycle of the subject, a portion of the aorta that is between the regions does not contact the element.   
     
     
         53 . The method of  claim 52 , wherein applying the forces comprises applying forces to two opposing regions of the aorta. 
     
     
         54 . The method of  claim 52 , wherein the element includes a stent that has a non-circular cross-section, and wherein placing the element inside the aorta comprises placing the stent inside the aorta. 
     
     
         55 . The method of  claim 52 , wherein the element includes a rigid element, and wherein placing the element inside the aorta comprises placing the rigid element inside the aorta. 
     
     
         56 . The method of  claim 52 , wherein the element includes a flexible element, and wherein placing the element inside the aorta comprises placing the flexible element inside the aorta. 
     
     
         57 . The method of  claim 56 , wherein the element is configured to flex in response to a cardiac cycle of the subject, and wherein placing the element inside the aorta comprises placing inside the aorta the element that is configured to flex in response to the cardiac cycle. 
     
     
         58 . The method of  claim 57 , wherein the element is configured to flex passively in coordination with the cardiac cycle of the subject, and wherein placing the element inside the aorta comprises placing inside the aorta the element that is configured to flex passively in coordination with the cardiac cycle. 
     
     
         59 . The method of  claim 57 , further comprising flexing the element in coordination with the cardiac cycle, using a control unit. 
     
     
         60 . A method of stimulating baroreceptors to treat a disease relating to hypertension of a subject, the subject having an aorta with a wall, the method comprising:
 providing an implant having a first structure on a first end and a second structure on a second end opposite the first end, wherein three or more longitudinal contact regions extend in a longitudinal direction between the first end and the second end; and   placing the implant in the aorta with an expanded configuration, wherein the three or more longitudinal contact regions contact the wall of the aorta and define three or more contact regions of the wall alternating with three or more non-contact regions around the wall, wherein the three or more contact regions of the wall alternating with the three or more non-contact regions stretch the wall of the aorta sufficiently to stimulate the baroreceptors and treat the disease.   
     
     
         61 . The method of  claim 60 , wherein the three or more contact regions of the wall alternating with the three or more non-contact regions around the wall shape the wall to a substantially polygonal cross-sectional shape having from three to five sides. 
     
     
         62 . The method of  claim 61 , wherein the three or more longitudinal contact regions comprise from three to five longitudinal contact regions to shape the cross-section of the wall to the substantially polygonal shape having from three to five sides. 
     
     
         63 . The method of  claim 62 , wherein the three or more longitudinal contact regions comprise four longitudinal contact regions spaced apart to shape the wall to a cross-sectional shape having four flatter sides. 
     
     
         64 . The method of  claim 60 , wherein the three or more longitudinal contact regions are spaced apart with distances sized to increase a cross-section of the aorta and flatten the non-contact regions in order to lower blood pressure. 
     
     
         65 . The method of  claim 60 , wherein the three or more contact regions of the wall alternating with the three or more non-contact regions around the wall shift a pressure-strain curve of a hypertensive subject upwards and increase a gradient of the pressure-strain curve. 
     
     
         66 . The method of  claim 60 , further comprising identifying the subject as suffering from hypertension; and wherein placing the implant in the aorta comprises placing the implant in the aorta in response to the identifying, and wherein the three or more non-contact regions around the wall pulsate and stimulate the baroreceptors to treat the hypertension. 
     
     
         67 . The method of  claim 60 , wherein each of the three or more non-contact regions has a systolic radius of curvature more than 1.1 times a systolic radius of curvature in the absence of the implant. 
     
     
         68 . A method of treating a disease related to hypertension of a subject, the subject having baroreceptors and a central nervous system responsive to the baroreceptors, comprising:
 providing a passive flexible element having a non-circular cross-section, the passive flexible element comprising a first non-circular flexible end element and a second non-circular flexible end element, the first non-circular flexible end element coupled to the second non-circular flexible end element with three or more longitudinal struts extending therebetween,   coupling the passive flexible element having the non-circular cross-section to an aorta of the subject in a vicinity of the baroreceptors of the subject, by implanting the passive flexible element within the aorta, the passive flexible element being configured to flex passively in coordination with the cardiac cycle; and   facilitating, with the passive flexible element, an assumption of a non-circular cross-sectional shape by the aorta in the vicinity that is less circular than a shape of the aorta in the vicinity when the passive flexible element is not coupled to the aorta, wherein passive flexure of the first non-circular flexible end element and the second non-circular flexible end element in coordination with the cardiac cycle of the subject stimulates the baroreceptors to transmit signals to the central nervous system and treats the disease related to hypertension.   
     
     
         69 . The method of  claim 68 , further comprising reducing the disease by facilitating, with the passive flexible element, an assumption of a cross-sectional shape by the aorta in the vicinity, during diastole of the subject, that is less circular than a shape of the aorta in the vicinity, during systole of the subject. 
     
     
         70 . The method of  claim 68 , wherein implanting the passive flexible element comprises placing the passive flexible element inside the aorta on a side of the baroreceptor selected from the group consisting of: an upstream side and a downstream side. 
     
     
         71 . The method of  claim 68 , wherein implanting the first non-circular flexible end element and the second non-circular flexible end element comprises implanting the first non-circular flexible end element on a first side of the baroreceptor and implanting the second non-circular flexible end element on a second side of the baroreceptor, the first and second sides being respective sides selected from the group consisting of: an upstream side and a downstream side. 
     
     
         72 . The method of  claim 68 , wherein the passive flexible element is configured to flex passively in coordination with the cardiac cycle of the subject, and wherein facilitating the assumption of the non-circular cross-sectional shape by the aorta, during diastole, comprises, subsequent to implanting the passive flexible element, allowing the flexible element to flex passively in coordination with the cardiac cycle. 
     
     
         73 . The method of  claim 68 , wherein implanting the passive flexible element comprises coupling the first non-circular flexible end element and the second non-circular flexible end element to the aorta at a longitudinal separation from each other, the non-circular flexible end elements having non-circular cross-sections. 
     
     
         74 . The method of  claim 73 , wherein the longitudinal separation is between 5 mm and 20 mm. 
     
     
         75 . The method of  claim 73 , wherein the longitudinal separation is between 20 mm and 50 mm.