paraganglioma of carotid arterycarotid paraganglioma surgerycarotid atherosclerosis symptomscarotid insufficiency symptomscarotid body paragangliomacarotid paraganglioma neckcarotid occlusion symptomscarotid artery disease treatmentcarotid stenosis symptomssymptoms of carotid aneurysmcarotid blockage symptomscarotid stroke symptoms