Catheter system for acute neuromodulation
A neuromodulation system includes a first therapy element adapted for positioning within a superior vena cava, and a second therapy element adapted for positioning within a pulmonary artery. The first therapy element is carried on a first elongate flexible shaft, and the second therapy element is carried on a second elongate flexible shaft. One of the first and second shafts is slidably received within a lumen of the other of the first and second shafts—so that the second therapy element may be advanced within the body relative to the first therapy element. A stimulator is configured to energize the first therapy element within the first blood vessel to deliver therapy to a first nerve fiber disposed external to the superior vena cava and to energize the second therapy element within the pulmonary artery to deliver sympathetic therapy to a second nerve fiber disposed external to the pulmonary artery. For treatment of heart failure, the first nerve fiber may be a vagus nerve and the second nerve fiber may be a sympathetic nerve fiber.
1. A neuromodulation method for treating a patient, comprising:
positioning a first therapy element in a first blood vessel, the first therapy element carried on a first elongate shaft, wherein the elongate shaft includes
an outer sheath having a distal portion with an outer sheath distal tip, an anchoring element integral with the outer sheath and radially expandable from the distal portion of the outer sheath from a streamlined to an expanded position in response to axial compression of the outer sheath, the outer sheath further including a plurality of electrodes on the anchoring element, and a proximal portion proximal portion, and
an inner sheath slidably disposed within the outer sheath and including a distal portion with an inner sheath distal tip, and a proximal portion, the inner and outer sheath having distal portions fixed to one another such that relative longitudinal positions of the outer sheath distal tip and the inner sheath distal tip on the elongate shaft remain constant when relative longitudinal positions of the proximal portions of the inner and outer sheaths are changed,
moving the electrodes into contact with an interior wall of the first blood vessel by causing relative longitudinal movement of proximal portions of the inner and outer sheaths in opposite directions while the distal portions remain fixed to one another, said relative longitudinal movement of the proximal portions causing axial compression of the outer sheath, thereby moving the expandable anchoring element from the streamlined position to the expanded position;
positioning a second therapy element in a second blood vessel different from the first blood vessel, the second therapy element carried on a second shaft, wherein one of the first and second shafts is slidably received within a lumen of the other of the first and second shafts; and
activating a stimulator to (a) energize the first therapy element within the first blood vessel to deliver therapy to a first nerve fiber disposed external to the first blood vessel and (b) energize the second therapy element within the second blood vessel to deliver sympathetic therapy to a second nerve fiber disposed external to the first blood vessel.
2. The method of claim 1 , further including the step of controlling the stimulator to energize the first and second therapy elements in response to said sensed heart rate and/or blood pressure.
3. The method of claim 1 , wherein positioning the second therapy element includes at least partially expanding the second therapy element into contact with surrounding walls of the second blood vessel.
4. The method of claim 1 , wherein positioning the second therapy element in the second blood vessel comprises positioning the second therapy element within a pulmonary artery.
5. The method of claim 4 , wherein positioning the second therapy element includes inflating an expandable balloon coupled to the second therapy element when the first therapy element is retained in the first blood vessel such that expansion of the balloon causes the second therapy element to be carried by blood flow from the heart to the pulmonary artery.
6. The method of claim 4 , wherein positioning the first therapy element includes positioning the first therapy element within a superior vena cava.
7. The method of claim 1 wherein the anchoring element includes elongate splines, and wherein in the step of moving the electrodes, the axial compression of the outer sheath causes the splines to bow outwardly to move the anchoring element to the expanded position.