January 18, 2016

Hypertension in the New World of Ten


EDITOR’S NOTE: This is the first in a two-part series on coding hypertension in ICD-10. In this installment, Rhonda Buckholtz provides a clinical context for hypertension.

Understanding clinical conditions and relationships is an important component of coding. With many code assignments currently being paid in accordance with quality measures and assignments, using a code with less specificity when more detailed information is found in the medical record can hurt your bottom line. It’s also important that you work with your physicians on clinical documentation improvement.

Hypertension is diagnosed when systolic blood pressure is consistently elevated above 140 mm Hg or when diastolic blood pressure is above 90 mm Hg. A single elevated blood pressure finding (such as white coat syndrome) is not enough to qualify for hypertension. There are exceptions to this rule for when a physician determines that the patient has hypertensive presentation with unequivocal evidence of life-threatening end-organ damage, such as hypertensive emergency, or when blood pressure is greater than 220.125 mm Hg without end-organ damage.

In about 90-95 percent of patients with hypertension, no cause can be found. In this case, it is called essential, benign, or primary hypertension. Malignant hypertension is extremely high blood pressure that develops quickly and causes organ damage.

Untreated malignant hypertension can cause aortic dissection, pulmonary edema, myocardial infarction, heart failure, stroke, and death. Immediate medical treatment is necessary.

If hypertension is caused by another condition, it is called secondary hypertension. Secondary hypertension may be caused by any of the following:

  • Diabetes mellitus
  • Polycystic kidney disease
  • Renovascular hypertension
  • Cushing syndrome
  • Glomerular disease
  • Thyroid conditions
  • Hyperparathyroidism
  • Obesity
  • Aldosteronism
  • Coarctation of the aorta
  • Medication
  • Sleep apnea

Hypertensive heart disease is any number of heart conditions that arise due to hypertension, including heart failure, left ventricular hypertrophy, and coronary artery disease.

Hypertension causes heart failure by causing left ventricular hypertrophy (thickening of the muscular ventricle), meaning the muscle relaxation is shorter between heartbeats. This causes the body to retain fluids and sodium and increase the heart rate, as it is harder for the heart to fill with enough blood to supply the body’s organs.

Hypertension puts added pressure on the arterial walls, and over time it causes damage that makes them more susceptible to narrowing and plaque buildup. This plaque can block the coronary arteries that supply blood to the heart and deprive it of receiving enough oxygen. The plaque may lead to formation of small blood clots, which may cause myocardial infarction.

Hypertension can damage the blood vessels, including those that lead to the kidneys. If this occurs, it limits the kidneys’ ability to function. If the kidneys’ blood vessels are damaged, they will not be able to remove waste and extra fluid form the body. The kidneys also produce renin, which helps balance sodium and potassium levels in the blood and fluid levels in the body. If the kidneys are not working properly, they may release renin, which can cause blood pressure to rise even higher.

Hypertension is the second leading cause of kidney failure in the United States (diabetes is the leading cause).

In the second installment, Rhonda Buckholtz discusses the complexities of coding hypertension in ICD-10.


Rhonda Buckholtz is the vice president of practice optimization for Eye Care Leaders. She has more than 25 years of experience in healthcare, working in the management, reimbursement, billing, and coding sectors, in addition to being an instructor. She is a past co-chair for the WEDI ICD-10 Implementation Workgroup, Advanced Payment Models Workgroup and has provided testimony ongoing for ICD-10 and standardization of data for NCVHS. Rhonda spends her time on practice optimization for Eye Care Leaders by providing transformational services and revenue integrity for Ophthalmology practices. She was instrumental in developing the Certified Ophthalmology Professional Coder (COPC) exam and curriculum for the AAPC. Rhonda is a member of the ICD10monitor editorial board and makes frequent appearances on Talk Ten Tuesdays.

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