Q&A: Defining Subacute

Q: The primary physician documented subacute cerebral infarction and I am wondering whether I should code this to a new cerebral vascular accident (CVA) or not since the term “subacute” doesn’t really fall anywhere.

A: The Official Guidelines for Coding and Reporting offers no definition as to what is considered acute, subacute, or chronic. I have found subacute to mean something in between acute and chronic which is a vague description at best! For questions such as this I refer to the American Hospital Association’s Coding Clinic for ICD-9-CM (ICD-10-CM/PCS)® for assistance. Coding Clinic, First Quarter 2011, p. 21 states:

Question: How is the diagnosis documented as “subacute deep vein thrombosis (DVT) code? There are index subentries for acute and chronic, but not for subacute?

Answer: Assign code 45.39, acute venous embolism and thrombosis of other specified veins, for a diagnosis of subacute DVT.

Now, this reference does not specifically describe a CVA but does offer guidance that the term subacute is interpreted as being acute. But I would like to see more guidance related to CVA. So let’s look at Coding Clinic, Second Quarter 2013, p. 10

Question: The patient suffered a subacute ischemic right posterior watershed infarct with small focus of subacute hemorrhage. How should this be coded?

Answer: Assign 434.91 Occlusion of Cerebral arteries, cerebral artery occlusion, unspecified with cerebral infarction AND 431- intracerebral hemorrhage, for the description subacute ischemic right posterior parietal watershed infarct with small focus of subacute hemorrhage. In this instance the patient had an ischemic stroke as well as a hemorrhagic stroke.

Although this Coding Clinic addresses the fact that two codes would be assigned because there was both an ischemic and hemorrhagic stroke, it also reinforces that the wording of subacute would apply to the codes for a CVA versus codes for a history of CVA. Coding Clinic offers much guidance when we encounter those “grey” areas of the code set and should be the reference that you seek in such situations.

Editor’s Note: CDI Boot Camp Instructor Laurie Prescott, RN, MSN, CCDS, CDIP, AHIMA Approved ICD-10-CM/PCS Trainer, answered this question. Contact her at lprescott@hcpro.com. For information regarding CDI Boot Camps offered by HCPro visit www.hcprobootcamps.com/courses/10040/overview.