ICD-10 Hypertension Eases Coding Stress
The ICD-9-CM hypertension table is eliminated and more concise codes capture the “silent killer.”
by Rhonda Buckholtz, CPC, CPMA, CPC-I, CENTC, CGSC, COBGC, CPEDC
According to the Centers for Disease Control and Prevention (CDC), hypertension affects one in three adults in the United States, or approximately 68 million people. It contributes to one out of every seven deaths and to nearly half of all cardiovascular disease–related deaths, including stroke.
ICD-10-CM codes for hypertension are similar to those in ICD-9-CM. Coding for hypertension (without complications) is easier in ICD-10-CM because there is no “benign” vs. “malignant” issue — there is only essential hypertension, indicated by code I10 Essential (primary) hypertension.
If hypertension affects a body system, combination codes come into play. The code set addresses Hypertensive heart disease with category I11, Hypertensive chronic kidney disease with category I12, and Hypertensive heart and chronic kidney disease with category I13.
Hypertensive Heart Disease
Hypertensive heart disease is the No. 1 cause of death associated with high blood pressure. It refers to a group of disorders that includes heart failure, ischemic heart disease, hypertensive heart disease, and left ventricular hypertrophy. If the patient has hypertensive heart disease, the family practitioner must make the connection with the conditions for the combination code to be assigned. Documentation must state “heart failure due to hypertension” or imply a causal relationship, “hypertensive heart failure,” to assign a code from category I11.
Guidelines state there is a presumptive cause and effect relationship between hypertension and chronic kidney disease.
If a patient has all three conditions present — hypertension, heart disease, and chronic kidney disease (CKD) — the guidelines state the connection must be made for the heart disease and hypertension, but not for the CKD and hypertension.
Assessment: 1. Hypertension 2. Chronic diastolic congestive heart failure.
I50.32 Chronic diastolic (congestive) heart failure
Rationale: Because there is no causal relationship indicated, the two conditions are coded separately.
Assessment: Hypertension with hypertensive chronic diastolic congestive heart failure.
I11.0 Hypertensive heart disease with heart failure
Rationale: The causal relationship is indicated, so the first-listed code is now different. The instructional note under code I11.0 states that the second code is still necessary to identify the type of heart failure.
The patient is a 75-year-old female with hypertension and stage 3 CKD with a creatinine of 1.8.
I12.9 Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
N18.3 Chronic kidney disease, stage 3 (moderate)
Acute Myocardial Infarction (AMI)
More than a million people each year in the United States suffer myocardial infarctions (MIs). The site of the MI will reflect the coronary artery experiencing the ischemia. For example, an MI of the anterior wall is caused by ischemia in the left anterior descending coronary artery.
The heart consists of three tissue layers:
- Endocardium: This is the innermost layer, which lines the heart’s chambers and is bathed in blood.
- Myocardium: The myocardium is the thick middle layer of the heart. Its cells are unique in that they physically resemble skeletal muscle, but have electrical properties similar to smooth muscle. These cells also contain specialized structures that help to rapidly conduct electrical impulses from one muscle cell to another, enabling the heart to contract.
- Pericardium: This is a membrane that surrounds the heart. It holds the heart in place and helps it to work properly.
MI or AMI, commonly known as a heart attack, is the interruption of blood supply to a part of the heart, causing heart cells to die. This is usually due to occlusion of a coronary artery following the rupture of vulnerable atherosclerotic plaque, which is an unstable collection of lipids and white blood cells (especially macrophages) in the wall of an artery. If left untreated for a sufficient time, the resulting ischemia and oxygen shortage can cause damage or death of myocardium.
The general surgeon is called to the ED. A 59-year-old man has presented with a 90-minute history of severe, crushing chest pain. His ECG shows 3 mm ST segment elevation, and he is diagnosed with an AMI. He is given loading doses of aspirin and clopidogrel. Forty-five minutes after admission, he undergoes successful primary percutaneous coronary intervention (PCI) with the insertion of a drug eluting stent into his critically narrowed left anterior descending coronary artery. By the time he is returned to the coronary care unit 30 minutes after the procedure, he is pain free and there is partial resolution of his ECG changes.
I21.02 ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery
Secondary Diagnosis Codes
Instructional notes under categories I21 ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction and I22 Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction state that additional codes should be used to identify:
- Exposure to environmental tobacco smoke (Z77.22 Contact with and (suspected) exposure to environmental tobacco smoke (acute) (chronic))
- History of tobacco use (Z87.891 Personal history of nicotine dependence)
- Occupational exposure to tobacco smoke (Z57.31 Occupational exposure to environmental tobacco smoke)
- Tobacco dependence (F17.- Nicotine dependence)
- Tobacco use (Z72.0 Tobacco use)
Inform the provider of the specific terminology as it relates to smoking history to ensure proper codes are assigned for these conditions.
Code Z92.82 Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to a current facility is also included in the instructional note that indicates tissue plasminogen activator (tPA) administration.
TPA is a fast-acting enzyme that dissolves blood clots. It can be produced naturally by cells in the walls of blood vessels or prepared through the use of genetic engineering. TPA is used in the coronary arteries during heart attacks, and in the cranial arteries in certain types of strokes. Administering tPAs during the first few hours following the incident can minimize the damage to the heart muscle and improve the patient’s chances of survival.
Code Z92.82 is assigned as a secondary diagnosis at the receiving facility when a patient is received in transfer into a facility and the documentation indicates the patient was administered tPA within the last 24 hours prior to admission to the current facility.
The instructional note under Z92.82 states to code first the condition requiring tPA administration, such as acute cerebral infarction (I63- Cerebral infarction) or acute myocardial infarction (I21-, I22-). This code would be assigned even if the patient is still receiving the tPA at the time he or she is received into the current facility.
Patient presents to a rural hospital with chest pressure on and off, arm and shoulder pain, and rapid heartbeat for the past hour. He is diagnosed with AMI of the left main coronary artery and is administered tPA. He is stabilized and transferred to another facility that has an advanced coronary unit within two hours.
Physician at first hospital:
I21.01 ST elevation (STEMI) myocardial infarction involving left main coronary artery
Physician at second hospital:
Rhonda Buckholtz, CPC, CPMA, CPC-I, CENTC, CGSC, COBGC, CPEDC, is vice president of ICD-10 Training and Education at AAPC.