A system, comprising: an neuromodulation element configured to modulate nerves at or otherwise proximate to a renal artery of a patient, wherein the neuromodulation element includes a plurality of electrodes spaced apart from one another, wherein the neuromodulation element has a delivery state and a deployed state and at least a portion of the neuromodulation element is helical in the deployed state; a first elongated shaft having a first portion configured to be intravascularly positioned while the neuromodulation element modulates the nerves, and a second portion proximal to the first portion, the second portion configured to be extracorporeally positioned while the neuromodulation element modulates the nerves; an occlusion member extending around a segment of the first portion, a perfusion intake proximal to the occlusion member, a perfusion outlet distal to the occlusion member and a perfusion lumen extending between the perfusion intake and the perfusion outlet; a sampling port distal to the segment; a sampling lumen extending from the sampling port toward the second portion; an inflation opening within the occlusion member; an inflation lumen extending from the inflation opening toward the second portion; a second elongated shaft having a distal end portion coupled to the neuromodulation element; a device opening distal to the sampling port; a device lumen extending from the device opening toward the second portion; and the second shaft is configured to slidingly extend through the device lumen such that the distal end portion extends through the device opening, further comprising an analyzer configured to analyze a biological sample from the patient for a biological parameter that changes in response to modulating the nerves, and wherein: the analyzer is operably connected to the second portion; and the sampling lumen extends from the sampling port along the first shaft to the analyzer. an neuromodulation element configured to modulate nerves at or otherwise proximate to a renal artery of a patient, wherein the neuromodulation element includes a plurality of electrodes spaced apart from one another, wherein the neuromodulation element has a delivery state and a deployed state and at least a portion of the neuromodulation element is helical in the deployed state; a first elongated shaft having a first portion configured to be intravascularly positioned while the neuromodulation element modulates the nerves, and a second portion proximal to the first portion, the second portion configured to be extracorporeally positioned while the neuromodulation element modulates the nerves; an occlusion member extending around a segment of the first portion, a perfusion intake proximal to the occlusion member, a perfusion outlet distal to the occlusion member and a perfusion lumen extending between the perfusion intake and the perfusion outlet; a sampling port distal to the segment; a sampling lumen extending from the sampling port toward the second portion; an inflation opening within the occlusion member; an inflation lumen extending from the inflation opening toward the second portion; a second elongated shaft having a distal end portion coupled to the neuromodulation element; a device opening distal to the sampling port; a device lumen extending from the device opening toward the second portion; and the second shaft is configured to slidingly extend through the device lumen such that the distal end portion extends through the device opening, further comprising an analyzer configured to analyze a biological sample from the patient for a biological parameter that changes in response to modulating the nerves, and wherein: the analyzer is operably connected to the second portion; and the sampling lumen extends from the sampling port along the first shaft to the analyzer. the analyzer is operably connected to the second portion; and the sampling lumen extends from the sampling port along the first shaft to the analyzer.