Some important information about high blood pressure (hypertension) and understanding the different types of hypertension.
Hypertension represents the most common reason for healthcare office visits in the United States. It is estimated that over 50 million Americans and over one billion people worldwide have hypertension. Recently, the seventh report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of Hypertension changed the definition of hypertension to greater than 120/80mmHg. This will increase the number of Americans who are candidates for aggressive risk factor intervention and drug treatment for newly diagnosed hypertension.
What is Renovascular Hypertension?
The vast majority of patients with hypertension have primary hypertension. That is, there is no underlying medical reason for hypertension, they just have high blood pressure. Approximately, 10 percent of patients who have secondary hypertension, which is an underlying reason, and if identified and treated, would cure or lower the high blood pressure.
The Primary Cause of Hypertension
The most common causes of hypertension include chronic kidney disease and medications, for example, non-steroidal anti-inflammatory drugs (ibuprofen, etc.), sympathomimetics (decongestants, antihistamines), oral contraceptives, anabolic steroids, illicit substances (cocaine), and over the counter dietary supplements (ephedra).
The Secondary Cause of Hypertension
One important secondary cause of hypertension, which has good results from treatment, is renal artery stenosis (RAS). Stenosis means narrowing, or partial blockage of the blood vessel that carries blood to the kidney, in addition, RAS may occur in younger (commonly female) patients due to abnormal development of the artery wall known as fibromuscular dysplasia.
The Cause of Hypertension in Older Generations
The cause of Renovascular Hypertension in older patients is usually the hardening of the arteries or atherosclerosis. Atherosclerosis is the most common cause of RAS. Discovering RAS in patients with vascular disease in other areas is common(coronary, carotid, abdominal aorta, peripheral arteries).
“RAS is associate with certain clinical clues, which, if appreciated by physicians, may result in earlier diagnosis.”
Renal artery stenosis (RAS) Indicators
RAS correlates with certain clinical clues, which, if appreciated by physicians, may result in earlier diagnosis.
Some of these clues include:
- Worsening blood pressure control in someone whose blood pressure is previously under control.
- The need for >3 medications at maximal doses for blood pressure control.
- Severe high blood pressure with a symptom (heart attack, stroke, aortic dissection, rupture).
- Development of renal failure when taking certain medications: Angiotensin
- Converting Enzyme Inhibitors (captopril, enalapril, lisinopril, etc.).
- Angiotensin II Receptor Antagonists (losartan, candesartran, irbesartran, etc.).
- High blood pressure and artery disease in the coronary, carotid, lower extremity arteries, or abdominal aortic aneurysm.
- A major difference in kidney size from one side to the other.
- Repeated episodes of sudden severe heart failure, especially if the heart squeezing function is normal.
- Kidney failure without an obvious cause.
- Risk factors for Renovascular hypertension.
In patients with atherosclerosis elsewhere, the likelihood of finding significant RAS is anywhere between 30-50%. RAS is associated with several medical conditions, including increasing high blood pressure (a serious predictor of heart attack, stroke, kidney failure, and premature death), kidney failure, and recurrent heart failure.
How is Renovascular Hypertension diagnosed?
There are several excellent non-invasive tests for the diagnosis of RAS including ultrasound, nuclear imaging tests, magnetic resonance arteriography, and spiral computed tomography (CT) scanning. All of these have their advantages and disadvantages, yet all have a high degree of accuracy.
Overall, treatment of RAS generally falls into three categories:
- Medical treatment
- Open surgery
- Endovascular Therapy
Conclusion
In conclusion, making the decision regarding which option is best by consulting vascular experts who take into consideration the level of high blood pressure, the degree of kidney function problems, the overall health of the patient, the risk of the chosen procedure, and the likelihood of the improvement is ideal.
Whether fixing RAS prevents progression to kidney failure is uncertain, therefore, major clinical trials will begin shortly with the hope of answering this important question.