A catheter apparatus for assessing denervation comprising: an elongated catheter body having a proximal end and a distal end, a longitudinal axis extending in a longitudinal direction between the distal end and the proximal end; a deployable structure coupled to the catheter body, the deployable structure being deployable outwardly from the longitudinal axis of the catheter_ body to a deployed arrangement and contractible inwardly toward the longitudinal axis of the catheter body to a contracted arrangement, the deployable structure comprising a deployable sleeve, wherein at least a portion of the catheter body is disposed inside the deployable sleeve, and an anti-occlusion feature configured to permit fluid flow in a vessel of a patient between a proximal end and a distal end of the deployable structure in the deployed arrangement; one or more ablation elements disposed on the deployable sleeve to move outwardly and inwardly with the deployable sleeve, the one or more ablation elements suitable for being powered to apply ablation energy to the vessel; one or more stimulation elements spaced from each other and disposed on the deployable sleeve to move outwardly and inwardly with the deployable sleeve, the one or more stimulation elements being powered to supply nerve stimulating signals to the vessel; and one or more recording elements spaced from each other and from the one or more stimulation elements, the one or more recording elements being disposed on the deployable sleeve to move outwardly and inwardly with the deployable sleeve and being configured to record evoked electrical responses of the vessel in response to the nerve stimulating signals an elongated catheter body having a proximal end and a distal end, a longitudinal axis extending in a longitudinal direction between the distal end and the proximal end; a deployable structure coupled to the catheter body, the deployable structure being deployable outwardly from the longitudinal axis of the catheter_ body to a deployed arrangement and contractible inwardly toward the longitudinal axis of the catheter body to a contracted arrangement, the deployable structure comprising a deployable sleeve, wherein at least a portion of the catheter body is disposed inside the deployable sleeve, and an anti-occlusion feature configured to permit fluid flow in a vessel of a patient between a proximal end and a distal end of the deployable structure in the deployed arrangement; one or more ablation elements disposed on the deployable sleeve to move outwardly and inwardly with the deployable sleeve, the one or more ablation elements suitable for being powered to apply ablation energy to the vessel; one or more stimulation elements spaced from each other and disposed on the deployable sleeve to move outwardly and inwardly with the deployable sleeve, the one or more stimulation elements being powered to supply nerve stimulating signals to the vessel; and one or more recording elements spaced from each other and from the one or more stimulation elements, the one or more recording elements being disposed on the deployable sleeve to move outwardly and inwardly with the deployable sleeve and being configured to record evoked electrical responses of the vessel in response to the nerve stimulating signals