This study is exploring whether use of losartan, a medicine commonly used to lower blood pressure, is effective at treating abnormal nighttime blood pressure in children and young adults who have sickle cell disease. To participate in this study, you or your child must be 5 to 25 years old and have high blood pressure and a certain type of sickle cell disease: hemoglobin SS or Sβ0 thalassemia. This study is located in Birmingham, Alabama.
High blood pressure is a major risk factor for cardiovascular disease. Without treatment, you can have a transient ischemic attack (TIA) or stroke, heart attack, enlarged heart, heart failure, peripheral vascular disease (such as poor circulation and pain in your legs), aneurysms, kidney disease, and broken blood vessels in your eyes. Treatment includes making changes recommended by your healthcare provider.
For example, a 2015 study known as the SPRINT trial found that patients who lowered their systolic blood pressure to around 120 mm Hg were 27 percent less likely to die during the study period, compared with those whose treatment target was to lower their blood pressure to less than 140 mm Hg. (The SPRINT study made headlines in 2015 when the trial was abruptly cut short because the findings were so significant.)
Low blood pressure is also known as hypotension. This is usually defined in an adult as a systolic recording of less than 90 mmHg, although it has been suggested that for elderly people, below 110 mmHg is a more appropriate definition. Blood pressure and heart rate are controlled by the autonomic nervous system (the nervous system that controls bodily functions that we do not have to think about).                                                                                                                                                                                                
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Health care providers measure blood pressure with a sphygmomanometer (sfig-mo-muh-NAH-muh-ter), which has a cuff that's wrapped around the upper arm and pumped up to create pressure. When the cuff is inflated, it squeezes a large artery in the arm, stopping the blood flow for a moment. Blood pressure is measured as air is gradually let out of the cuff, which allows blood to flow through the artery again.
There are a number of factors that likely work together to cause high blood pressure. A family history of high blood pressure can make you more likely to develop the condition, so genetics likely plays a role. High salt intake (too much salt in the diet) or salt sensitivity occurs in some people, which can lead to hypertension, particularly in the elderly, African Americans, people who are obese, or people with chronic kidney (renal) disease.
The cuff is placed around the upper arm and inflated with an air pump to a pressure that blocks the flow of blood in the main artery that travels through the arm. The arm is held at the side of the body at the level of the heart, and the pressure of the cuff is gradually released. As the pressure decreases, a health practitioner listens with a stethoscope over the artery at the front of the elbow or an electronic machine senses the pulsation. The pressure at which the practitioner (or machine) first hears a pulsation from the artery is the systolic pressure (the top number). As the cuff pressure decreases further, the pressure at which the pulsation finally stops is the diastolic pressure (the bottom number).
Pulse pressure (the difference between systolic and diastolic blood pressure) is frequently increased in older people with hypertension. This can mean that systolic pressure is abnormally high, but diastolic pressure may be normal or low a condition termed isolated systolic hypertension.[59] The high pulse pressure in elderly people with hypertension or isolated systolic hypertension is explained by increased arterial stiffness, which typically accompanies aging and may be exacerbated by high blood pressure.[60]
As you age, prevention becomes even more important. Systolic pressure tends to creep up once you’re older than 50, and it’s far more important in predicting the risk of coronary heart disease and other conditions. Certain health conditions, such as diabetes and kidney disease, may also play a role. Talk to your doctor about how you can manage your overall health to help prevent the onset of hypertension.
Early signs of pulmonary arterial hypertension can be related to the trouble you have getting blood to your lungs to get oxygenated. You might experience shortness of breath and a fast heart beat while doing activities that are otherwise routine, such as climbing stairs. You might also have chest pain, a reduced appetite, and pain in your chest or upper right portion of your abdomen.
Exercise stress test: More commonly used for patients with borderline hypertension. This usually involves pedaling a stationary bicycle or walking on a treadmill. The stress test assesses how the body's cardiovascular system responds to increased physical activity. If the patient has hypertension this data is important to know before the exercise test starts. The test monitors the electrical activity of the heart, as well as the patient's blood pressure during exercise. An exercise stress test sometimes reveals problems that are not apparent when the body is resting. Imaging scans of the heart's blood supply might be done at the same time.
Hypertension with certain specific additional signs and symptoms may suggest secondary hypertension, i.e. hypertension due to an identifiable cause. For example, Cushing's syndrome frequently causes truncal obesity, glucose intolerance, moon face, a hump of fat behind the neck/shoulder (referred to as a buffalo hump), and purple abdominal stretch marks.[23] Hyperthyroidism frequently causes weight loss with increased appetite, fast heart rate, bulging eyes, and tremor. Renal artery stenosis (RAS) may be associated with a localized abdominal bruit to the left or right of the midline (unilateral RAS), or in both locations (bilateral RAS). Coarctation of the aorta frequently causes a decreased blood pressure in the lower extremities relative to the arms, or delayed or absent femoral arterial pulses. Pheochromocytoma may cause abrupt ("paroxysmal") episodes of hypertension accompanied by headache, palpitations, pale appearance, and excessive sweating.[23]
A person consistently showing blood pressure higher than 140/90 over several readings is considered to have hypertension. Doctors advise these people to make effective lifestyle changes to help lower their blood pressure, such as maintaining a healthy weight, including exercise in their daily routine, limiting salt and alcohol intake, and quitting smoking. The doctors will also recommend medication for hypertension depending on how much higher the BP is as compared to the normal blood pressure range and any other health problems that the patient faces.
Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017; pii: S0735-1097(17)41519-1. PMID: 29146535

Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017; pii: S0735-1097(17)41519-1. PMID: 29146535

Facial flushing: Facial flushing occurs when blood vessels in the face dilate. It can occur unpredictably or in response to certain triggers such as sun exposure, cold weather, spicy foods, wind, hot drinks and skin-care products. Facial flushing can also occur with emotional stress, exposure to heat or hot water, alcohol consumption and exercise — all of which can raise blood pressure temporarily. While facial flushing may occur while your blood pressure is higher than usual, high blood pressure is not the cause of facial flushing.