c. Heart conditions listed in 428, 429.-429.3, 429.8, and 429.9 described as due
to hypertension or hypertensive are coded to the 42 category. It is important to alert
the medical staff of the need to differentiate between (1) hypertensive heart disease and
(2) heart disease with nonrelated hypertension.
d. Renal conditions classified to categories 585, 586, or 587 with any condition
classified to category 41 or described as hypertensive renal disease is coded to the
e. A supplemental code for hypertension is used in addition to the principal code to
completely classify a diagnosis specified as "with hypertension" or "and hypertension."
4. A separate three-digit category 412 is provided to classify the diagnosis "old
myocardial infarction." "Old" is defined as healed, old, or past, as evidenced by history,
or diagnosed as a result of an abnormal EKG or other special investigation and
currently asymptomatic. This code will never be used as principal diagnosis, but is to
be used when appropriate as an additional code.
5. A repeat myocardial infarction occurring during the same period of hospitalization as
that for the acute myocardial infarction is coded to the specific site involved provided the
site is different from the previous site; for example, patient admitted with diagnosis of
acute myocardial infarction of anterolateral wall (code 41.) and while recovering in the
hospital, patient experiences a "repeat myocardial infarction of inferoposterior wall"
(code 41.3). Both codes would be used and in the correct sequence as they occurred.
6. The best rule to follow in assigning codes relating to cerebrovascular diseases is
use as many codes as necessary to identify all the component parts of a complex
diagnostic statement unless the Alphabetic Index or Tabular List directs otherwise.
a. Conditions classifiable to cerebrovascular disease, codes 43-438, include
those with mention of hypertension. An additional code should be used to identify the
hypertension and will follow the CVA-related codes.
b. If the cause for a cerebrovascular accident (CVA) is known, code 436 should not
be used as the principal diagnosis. Review the record, especially CT brain scan reports
for causes such as thrombosis, embolism.
c. Conditions resulting from the acute cerebrovascular disease stated as residuals
will be coded as additional codes. If the condition is still present at the time of
discharge, it will also be coded as an additional code. If conditions are stated as
transient and result from the cerebrovascular disease, omit coding.
d. When coding late effects of cerebrovascular disease, sequence the residual
code first followed by code 438.
7. ICD-9-CM differentiates between the conditions specified as high blood pressure
(hypertension) and elevated blood pressure
without a diagnosis of hypertension.