Venous Modulation of Collateral Perfusion of Cerebral Ischemia

Abstract

A patient in whom blood diversion due to cerebral venous steal is present, and abolishment of the cerebral venous steal is indicated, is treated by increasing the cerebral venous pressure in the patient. This increase in cerebral venous pressure restores the collapsed cerebral vasculature, thereby increasing cerebral blood flow. The increase in cerebral venous pressure may be achieved using an occluding catheter in the superior vena cava or the internal jugular veins, using external compression of the cervical veins, or any other suitable mechanism. The occlusion may be controlled precisely during treatment, possibly as a function of cerebral blood flow, and after treatment the patient may experience a persistent effect because the cerebral vasculature is no longer collapsed.

1 . A method for treating cerebral ischemia, comprising:
 selecting a patient in whom blood diversion due to cerebral venous steal is present and abolishment of the cerebral venous steal is indicated, the cerebral venous steal caused by focally collapsed cerebral vasculature;   increasing a cerebral venous pressure in the patient using an occlusion of one or more veins coupled to the collapsed cerebral vasculature;   maintaining the increased cerebral venous pressure for a period of time sufficient to restore at least a portion of the patient's collapsed cerebral vasculature; and   removing the occlusion of the one or more veins coupled to the collapsed cerebral vasculature.   
     
     
         2 . The method of  claim 1 , wherein the patient is suffering from a stroke. 
     
     
         3 . The method of  claim 1 , wherein the occlusion is of a portion of the patient's superior vena cava. 
     
     
         4 . The method of  claim 1 , wherein the occlusion is of a portion of the patient's superior vena cava between the patient's right aorta and azygos vein. 
     
     
         5 . The method of  claim 1 , wherein the occlusion is of one or both of a patient's interior jugular veins. 
     
     
         6 . The method of  claim 1 , wherein the occlusion is achieved by an expandable balloon placed in the one or more veins. 
     
     
         7 . The method of  claim 1 , wherein the occlusion is achieved by expanding a cervical cuff placed around the patient's neck to press against the patient's cervical veins. 
     
     
         8 . The method of  claim 1 , further comprising:
 mapping the cerebral blood flow and the venous pressure while the increased cerebral venous pressure is being maintained; and   adjusting the increased venous pressure as a function of at least the cerebral blood flow.   
     
     
         9 . The method of  claim 8 , wherein the cerebral blood flow is mapped using TCD waveforms. 
     
     
         10 . The method of  claim 1 , wherein cerebral blood flow heterogeneity and blood flow in ischemic areas of the patient's brain are maintained above the critical ischemic threshold. 
     
     
         11 . An apparatus for treating cerebral ischemia, comprising:
 an elongated tubular member for insertion into a patient's superior vena cava, the tubular member having proximal and distal ends;   an expandable occluder located at the distal end of the tubular member, the occluder having an expanded state and a collapsed state;   a pressure measurement device coupled to the tubular member and configured to measure a pressure at the distal end of the tubular member;   a hemodynamic effect measurement device configured to obtain a measure of cerebral blood flow in a patient; and   a controller coupled to the occluder for actuating the occluder between the expanded and collapsed states, and in communication with the pressure measurement device to obtain a measured venous pressure and to the hemodynamic effect measurement device to obtain the measure of cerebral blood flow, wherein the controller is programmed to actuate the expandable occluder as a function of the measured venous pressure and the measure of cerebral blood flow.   
     
     
         12 . The apparatus of  claim 11 , wherein the expandable occluder comprises an elastomeric balloon. 
     
     
         13 . The apparatus of  claim 11 , wherein the expandable occluder is configured to fit within a portion of a patient's superior vena cava. 
     
     
         14 . The apparatus of  claim 11 , wherein the expandable occluder is configured to fit within one or both of a patient's interior jugular veins. 
     
     
         15 . The apparatus of  claim 11 , wherein the expandable occluder comprises an expandable cervical cuff configured to be placed around a patient's neck to press against the patient's cervical veins. 
     
     
         16 . The apparatus of  claim 11 , wherein the hemodynamic effect measurement device obtains a measure of cerebral blood flow using TCD waveforms.