Systems and methods for applying energy to denervate a pulmonary artery

A method for reducing neural activity of nerves around a blood vessel of a patient, the method comprising:

• selecting a catheter system comprising a handle, an inner catheter comprising a guidewire lumen, a transducer assembly slidably disposed over the inner catheter, an outer catheter, an expandable anchor having a distal end coupled to the inner catheter and a proximal end coupled to the outer catheter, a sheath slidably disposed over the outer catheter, and a separation sleeve slidably disposed over the sheath;
• inserting an introducer into the patient at an entry site;
• advancing a distal end of a guidewire to a target location within the blood vessel;
• advancing the catheter system through the introducer and over a proximal end of the guidewire via the guidewire lumen until an ultrasound transducer of the transducer assembly is in the target location within the blood vessel, the expandable anchor disposed within the sheath in a collapsed delivery state;
• actuating the introducer to prevent relative movement between the separation sleeve and the introducer such that the sheath is configured to move relative to the separation sleeve without relative movement between the transducer assembly and the patient;
• retracting the sheath to expose the expandable anchor within the blood vessel;
• moving the inner catheter and the outer catheter relative to each other to cause the expandable anchor to transition from the collapsed delivery state to an expanded deployed state, the expandable anchor configured to centralize the ultrasound transducer within the blood vessel in the expanded deployed state;
• actuating the ultrasound transducer to emit ultrasonic energy within the blood vessel to reduce neural activity of nerves around the blood vessel;
• moving the inner catheter and the outer catheter relative to each other to cause the expandable anchor to transition from the expanded deployed state to the collapsed delivery state;
• advancing the sheath over the expandable anchor to facilitate transitioning of the expandable anchor from the expanded deployed state to the collapsed delivery state upon movement of a distal region of the sheath relative to the expandable anchor without buckling the distal region of the sheath;
• and
• removing the catheter system from the patient.