Ask Dr. Z

Per your 2020 IR book, page 213, a vascular family is defined as a vessel that originates off the aorta or vena cava, and includes all branches of that vessel. The pulmonary artery originates off the right ventricle, and CPT 2021 Professional Edition, Appendix L, page 920, lists it as a vascular family. CPT instructional notes state: Primary mechanical thrombectomy is reported per vascular family using 37184 for the initial vessel treated & 37185 for second or all subsequent vessel(s) within the same vascular family. Per CPTA 9/2019, page 10, when treating additional families through a separate access site then used for the initial thrombectomy, modifier -59 should be appended to 37184. If a mechanical thrombectomy is performed on the right and left pulmonary arteries, appears these are in the same vascular family. Please explain why this would not be coded 37184, 37185 rather than 37184-50?