Blood Pressure & Hypertension

Introduction

Hypertension or high blood pressure is a common medical condition affecting over 50 million Americans. The majority are unaware they have this condition. The significance of the condition is that it is a major risk factor for heart disease, stroke and kidney failure. It contributes to over 180,000 deaths in the US each year. Only 21% of Americans with this condition are under proper treatment.

In adults, there is good evidence that regular screening for hypertension with early intervention and treatment will reduce the risk of cardiovascular disease and death.

The good news is that hypertension is controllable with the many medications available today. The better news for pilots and controllers is that just about any medications on the market today for hypertension except for centrally acting agents such as clonidine are approved for use when flying after an appropriate evaluation. You are a safer pilot and a healthier individual if you are flying with medication to control your blood pressure than those who ignore the condition and avoid monitoring and treatment.

Blood Pressure Standards

The American Heart Association has recently redefined blood pressure standards. The old myth that blood pressure should rise with age is false. The AHA standards based on considerable research do not make allowances for age. Many studies lead to the conclusion that the lower an individual’s blood pressure is, the lower the risk of heart disease. This is especially true for elevated levels, but holds true within the normal range also, The current standards are summarized below:

FAA Blood Pressure Standards

The FAA’s upper limit for blood pressure previously varied depending on a pilot’s age and class of certificate. The standards now allow certification for pressures up to 155/95 without an evaluation. Pilots with blood pressures above this level may still be certified after a cardiovascular evaluation (CVE). The standards set by the FAA should not be construed as healthy or “safe” levels. They are maximum levels. Blood pressure near these limits should be evaluated and treated as per the AHA guidelines.

The FAA delegated the authority to clear use of blood pressure medication when flying to the Aviation Medical Examiners (AME) if a Cardiovascular evaluation is otherwise normal. This change is to encourage pilots to get their elevated blood pressure evaluated, and treated if necessary, without reluctance due to medical certification issues.

The maximum allowable blood pressure for controllers used to be based on age, but more recently was modified to be the same as for airmen with the safety cut off at 155/95. For controllers, the FAA generally requires three blood pressure readings in the acceptable range before reinstating your medical qualification with Special Consideration. Once returned to controlling duty, the Regional Flight Surgeon will require an annual report from your treating physician regarding your current medications and blood pressure readings.

Initial Treatment Without Medication

Several steps not involving the use of prescription medications are nearly universally recommended for all people evaluated for hypertension. Risk factor modification prior to the use of medication is desirable, although somewhat difficult for some. These steps include achieving ideal body weight, lowering salt, fats and cholesterol in the diet, increasing fiber and heart protecting nutrients in the diet, participation in an exercise program with your physician’s recommendation and stopping use of tobacco products.

One study found morning caffeinated coffee raised blood pressure all day. Other testing is designed to look for treatable cause of hypertension such as thyroid disease, narrowing of the aorta or renal arteries, endocrine tumors and diabetes. Co-existent medical conditions should be treated. A study from Duke University in the American Heart Journal reports that depression is associated with poor blood pressure control.

Undiagnosed obstructive sleep apnea may be a cause of hypertension. Treatment for sleep apnea may improve blood pressure and lower risk factors for other diseases, as well as improving alertness and a sense of well being. Individuals with sleep apnea are disqualified from flying and controlling by the FAA until an acceptable treatment documents improvement in the condition.

Patients interested in self-monitoring should be aware that electronic home monitoring is easy. However, of the many devices available commercially very few have actually passed reliable validation testing. The American Heart Association does recommend devices with a memory or printouts be used.

FAA Cardiovascular Evaluation

The cardiovascular evaluation (CVE) required by the FAA may be performed by any treating physician, not necessarily the AME or a cardiologist. Note that the maximal stress test is not required for an initial evaluation. It should be performed IF CLINICALLY INDICATED. If your physician recommends additional tests BECAUSE THEY ARE MEDICALLY INDICATED, do the testing and protect your health. We strongly advised AGAINST doing testing that is not medically indicated “just because the FAA might want to see it.” If the FAA wanted it, they would ask for it. Extra testing can cause significant problems, administrative delays and expense.

The cardiovascular evaluation includes:

1. pertinent personal and family medical history
2. assessment of risk factors for heart disease
3. clinical exam with at least 3 BP readings
4. resting ECG
5. lab reports including fasting glucose, cholesterol (HDL & LDL), triglycerides, potassium and creatinine
6. exercise stress test, IF clinically indicated
7. report of medications, dosage, any side effects

FAA Policy on Blood Pressure Medications

If after the evaluation, your physician feels medication would be appropriate for your condition, many options exist. The FAA does not authorize some medications used mainly in the 1950’s and 1960’s, namely guanethidine, reserpine, guanadrel, guanabenz and methyldopa. In the Spring 2011, the FAA also stopped allowing clonidine for the treatment of high blood pressure. All other blood pressure medications that have been FDA approved are currently authorized, as are new reformulations of previously approved medications. Before flying on any medication, the pilot should tolerate the medication well without significant side effects. Provide reports from the treating physician to your AME at the time of your next physical to fly and then annually thereafter. In April of 2013, the FAA decided that hypertension reports should remain in your AME’s offices and are no longer required to be sent to the FAA for approval. Controllers are also required to submit documents to the Regional Flight Surgeon.

Different classes of medication and combinations of classes are prescribed to control blood pressure. The determination of which medication to prescribe depends on many factors. These factors include findings during the exam, co-existing medical conditions, lifestyle issues and even insurance coverage. A brief discussion of each major class of antihypertensive medication follows with a partial list of some medications in each class. New medications are continuously marketed, which is why the FAA does not attempt to publish a listing of “approved” medications. See the AMAS Medications section for more information.

Diuretics

Diuretics are also known as “fluid pills”. They increase urination and may decrease circulating blood volume. (“The lower the oil level, the lower the oil pressure”). Diuretics are generally well tolerated without side effects and are inexpensive. For these reasons, they are frequently a first-line recommendation for treating hypertension. Some diuretics increase the urine output of potassium (K+). Pilots on these diuretics should periodically have their blood potassium levels checked and the AME may want to see this information on an annual basis. Some diuretics in this subcategory include hydrochlorothiazide (HCTZ), furosemide (Lasix), Zaroxyolen and Diuril. Often these medications are combined in one pill with medications from another category for ease of use. Some diuretics are known as “potassium sparing.” These include Triamterene and Aldactone. Other diuretics combine the potassium wasting and potassium sparing characteristics in one pill, such as aldactazide, Dyazide, Maxzide and Moduretic.

Beta Blockers

Beta blockers work by interfering with the nervous system’s signals to the beta adrenergic nervous system. This part of the nervous system sends signals to increase the heart rate and dilate the bronchioles of the lungs in preparation for the primitive “fight or flight response.” By blocking this response, the heart rate slows and blood pressure falls, just like turning off the boost pump. This is the only category of medication proven to protect against a second heart attack and may have protective effects against a first heart attack.

Because the maximum heart rate is limited, pilots on this medication may have difficulty achieving their maximal predicted heart rate on treadmill stress tests. These medications are usually well tolerated but a small number of people will experience fatigue and decreased sexual function. People with diabetes or asthma should not take these medications unless specifically discussed with your physician. Examples of beta blockers include propanolol (Inderal), metoprolol (Lopressor, Toprol -XL), atenolol (Tenormin) and bisoprolol (Zebeta).

Alpha Blockers

Alpha blockers work by interfering with the nervous systems signals to the alpha adrenergic system. This part of the nervous system acts on the smooth muscles of the blood vessels and other parts of the body. When stimulated, the smooth muscles cause the vessels to constrict. The alpha blockers cause dilation of the vessels, increasing the available volume of the circulatory system and decreasing pressure. Think of them as adding a sump to the oil system without adding any oil. They are very effective in lowering blood pressure, but may do so too quickly, particularly when just starting the medication. The result may be noticeable lightheadedness when getting up, and even fainting, when just starting the medication. To avoid this side effect, most physicians initially prescribe reduced doses of the medication at bed time, gradually increasing the dose as tolerated.

The alpha blockers are also used to treat prostatic hypertrophy and increase urine flow. They may be an excellent choice for a male with both hypertension and prostatic hypertrophy as single drug treatment for both conditions. Examples include doxazosin (Cardura) and terazosin (Hytrin).

ACE inhibitors

Angiotensin Converting Enzyme (ACE) inhibitors block the formation of a series of compounds produced in the kidney that raise blood pressure. The kidney regulates blood pressure with chemicals secreted in response to how much blood flows into the kidneys. If the pressure is low, ACE is one of several chemicals in a cascade that triggers the body to retain more fluid and increase blood pressure. Inhibiting this cascade fools the body into thinking there is plenty of blood pressure for the kidney and shuts down the reaction to increase blood flow.

Because of the association of hypertension and kidney disease with diabetes, ACE inhibitors are an excellent first drug to use in individuals with both conditions. Black individuals do not respond as well to ACE inhibitors as do whites. The major side effect is an annoying and persistent cough in approximately 3-5 % of people using the medication. Examples of ACE inhibitors include lisinopril (Prinivil, Zestril), enalapril (Vasotec), captopril (Capoten), benazepril (Lotensin), fosinopril (Monopril), quinapril (Accupril) and ramapril (Altace).

Angiotensin-2 (AT-2) receptor blockers

Angiotensin receptor antagonists (“blockers”) have been shown to produce effects similar to ACE inhibitors. Rather than lowering levels of angiotensin II, the mechanism of action works by blocking receptors preventing this chemical from having an effect on the heart and blood vessels. The side effects from this category seem to be minimal but can include dizziness. Examples include Losartan (Cozaar); Candesartan (Atacand); Eprosartan (Teveten); Irbesartan (Avapro); Telmisartan (Micardis); and Valsartan (Diovan).

Calcium Channel Blockers

Calcium channel blockers work by impeding the flow of calcium into the muscles of the cardiovascular system. This interferes with the contraction of the blood vessels and slows electrical activity in some parts of the heart. This effect of the heart’s electrical activity may be beneficial in persons with arrhythmia’s (irregular heart rates) as it can simultaneously keep the heart rate and blood pressure controlled. The major potential side effects are headache and peripheral edema, swelling of the hands and feet. Examples include nifedipine (Adalat CC, Procardia XL), verapamil (Calan, Covera-HS, Verelan, Isoptin), amlodipine (Norvasc), nisoldipine (Sular) and diltiazem (Cardiazem).

FAA Clearance to Use Medications while Flying

After appropriate ground testing, pilots report use of medications to their AME at the time of the next medical and then annually. Controllers may get clearance on these categories of medications from the Regional Flight Surgeon before return to duty. In both cases the individual should show documentation of completion of the CVE and documentation that their blood pressure is well controlled without side effects after several days on their final dose of medication. The FAA has a web site with information of certification of individuals with hypertension.

Combinations of antihypertensive medications are also authorized for any class of FAA medical certification. Because hypertension is a risk factor for many more serious medical conditions, AMAS encourages all pilots and controllers with hypertension to seek appropriate evaluation and treatment for the condition and optimize the opportunity to retain a medical certificate for many years.

As of 9 Apr 2013, the FAA simplified their AME aeromedical decision protocol for hypertension and continues to allow the AME to issue a certificate after completion of an appropriate evaluation. The new guidance simply states that the airman needs to be stable on medications for a week and needs to bring a clinical status report from their treating provider at the time of the medical no more than once annually

The completed Cardiovascular Evaluations and other test results may be taken to your AME at the time of your next medical. However, without careful review, direct submittal often can result in significant delays in certification while the AME or FAA asks for clinical clarification. Often well-meaning specialists who are not trained in Aerospace Medicine fail to address all the aeromedically important aspects of a particular case. As a result, the case is returned without action pending further documentation, or worse the pilot receives a potentially unwarranted denial.

AMAS Aeromedical Assistance

For a more specific personal explanation to your questions or those concerning aeromedical certification, contact AMAS for a private consultation. For help in reporting treatment for and obtaining clearance from the FAA to fly or control with these conditions, refer to the AMAS Confidential Questionnaire. If you are an AMAS Corporate Member, these services are FREE to you.