Using your head when it comes to your heart

 - May 16, 2008, 10:44 AM

Cardiovascular disease (CVD) claims nearly a million lives a year in the U.S. (958,775 in 1999, the last year for which definitive figures are available). That works out to be one out of every 2.5 deaths, which equates to more than 2,600 CVD deaths a day or one every 33 sec.

Since 1900, CVD has been the number-one killer in the U.S. in every year except 1918, when the grievous battlefield losses of World War I surpassed it. Ranked against the other leading causes of death in the U.S., cardiac death leads cancer, its closest competitor, two to one. The leading causes of American death after cancer (with 549,838 deaths annually) are accidents (97,860), Alzheimer’s disease (44,536) and AIDS (14,802).

According to the federal Centers for Disease Control (CDC), if all forms of CVD were eliminated, overall life expectancy would rise some seven years. The elimination of cancer would extend overall life expectancy just three years. Such is the lethality of cardiac disease.

Coronary heart disease–the blockage of the blood vessels feeding the heart, the leading cause of coronary thrombosis (heart attack) and ventricular fibrillation–is such a sudden killer that it fells some 250,000 Americans before they can be hospitalized.

Stroke, the failure of blood vessels that supply the brain with oxygen and nutrients, is related to overall cardiovascular health. If it were considered as a separate cause of death, it would be surpassed only by heart disease and cancer. Strokes killed 167,366 Americans in 1999, accounting for one out of every 14.3 deaths. On average, someone in the U.S. suffers a stroke every 53 sec; every 3.1 min someone dies of one.

Getting Better, If Not Well

As compiled by both the CDC and the American Heart Association (AHA), between 1989 and 1999, cardiovascular disease death rates declined 15.6 percent, even though the overall number of deaths rose 2.1 percent. The decline has been variously traced to better health awareness among the general public, more effective treatment methods, reduced fat intake made possible by low-fat foods, a decline in smoking and a culture that sociologically rewards pro-health practices such as regular strenuous exercise. The rise in overall deaths is attributable to the progressive aging of the baby-boom generation.

According to sources within the FAA’s Aeromedical Office, some 25 percent of the appeals for recertification following loss of medical are for cardiovascular causes (the most common by far being hypertension, otherwise known as high blood pressure), a rate that places the pilot population slightly ahead of the rough norms for the general population, in which CVD is encountered in one out of every five people.

While the percentage of Americans developing the most common sort of heart disease appears to be dropping somewhat, the overall number of cases is rising, thanks to a growing aging population. These factors of health and aging have combined to produce a current life expectancy of 76.7 years.

It should be pointed out that the inevitable “apples and oranges” comparisons between two disparate populations, such as the U.S. general population and its pilot population, become ever shakier when one figures in the sexual makeup of both groups. The roughly 50/50 male/female demographic of the general population does not well reflect the 95/5 percent male/female makeup of the licensed-pilot population, an important factor as modern medical research discovers increased differences in the pathology rate of various illnesses among men and women. For instance, the overall rate of death from CVD is higher among women, listed as the primary cause of death for the 512,904 American women who died in 1999, the most recent year for which data is available. CVD accounted for the deaths of 38.6 percent of the American men who died during the same period. Increased rates of smoking among the baby-boom women now approaching post-middle age are suspected as a primary cause for this phenomenon.

The FAA’s Civil Aeromedical Institute (CAMI) tracks the health of the nation’s pilot population, in the process maintaining a massive amount of data that will soon be in a much more usable form than it is today. “The advent of CAMI’s decision support system will not only provide access to a huge amount of standardized data on the overall health of pilots,” said Dr. Warren Silberman, manager of CAMI’s aeromedical certification division, “but also help correlate that data to other existing federal databases, such as the Justice Department’s and NTSB’s, greatly aiding in tracking of pathologies and how those pathologies affect safety.”

The conversion of the literal mountains of pilot health files into a standardized computerized format has taken years, but the end is in sight, with the proverbial switch set to be flipped sometime this fall. Meanwhile, rough CAMI data lists the causes for refusal of medical certification as follows (in descending order):

• Hypertension (high blood pressure)

• Abdominal hernia

• Alcohol-related offenses (almost entirely drunk-driving offenses detected by cross-referencing CAMI data with the National Driver Register. Failure to list automotive alcohol-related offenses can result in suspension of an airman’s medical certificate.)

• Kidney stones

• Contact lenses and complications

• Allergic conditions

• Prostate and testicular diseases

• Hay fever

• Skin disease (including melanomas)

• Disk and spinal disorders

• Disturbances of consciousness

The pilot population should take heart (pardon the pun) that after hypertension, the next leading form of CVD in the general population (coronary heart disease) places a distant 20th. In an effort to bring many of its reinstatement procedures more in line with improved medical techniques, Dr. Silberman has spearheaded recent efforts to make it easier for airmen (and women) sidelined by cardiac problems to get back in the air. A summary of some of the results follows.

What Can Go Wrong and How the Rules Have Changed

Hypertension–Also known as high blood pressure, hypertension is by far the most common cardiovascular disease. As far as the FAA is concerned, hypertension begins when a pilot’s blood pressure exceeds 155/95, a liberal allowance considering that such a blood pressure is well above the usual 120/80 neighborhood considered to indicate good health. If you can control your hypertension via diet and exercise, so much the better; no special evaluation or certification are needed to stay flight-worthy.

If an FAA-approved oral medication is used, a follow-up examination must be performed by the candidate’s examining physician, with that examination subsequently reviewed by an AME. The exam must include documentation of the patient’s cardiac risk factors; a physical exam to look for side effects from the hypertension; a resting electrocardiogram; and a blood test to determine total cholesterol–both the good (high-density lipoprotein or HDL) and the bad (low-density lipoprotein, commonly known as LDL) triglycerides–as well as fasting blood sugar levels. A stress test is not required. Since most blood-pressure medicines need some time to take effect, a week or two is required to determine if the medication selected is effective and free of debilitating side effects.

Coronary heart disease (CHD)– While high blood pressure may be the most common form of cardiac disease, CHD is by far the biggest killer. It’s the cause of the classic coronary heart attack (otherwise known as a myocardial infarction, killing roughly one American per minute), the result of blockage of the crucial arteries supplying oxygen to heart tissues. CHD may provide a warning of its impending attack, such as angina pectoris (chest pain) or it may strike without any warning at all.

Pilots must wait at least six months after either a heart attack or after surgery that reopened the blocked coronary blood vessel(s) before applying for recertification under the special issuance rules listed in Part 67. As part of the FAA’s generally liberal attitude toward medical recertification, just about every sort of coronary artery clearance and repair are acceptable, including bypass grafting; angioplasty (inflating a tiny balloon inside a blocked artery to clear it); stent placement (reinforcing a weakened portion of artery with artificial materials); atherectomy (a mechanical technique for scraping fatty plaque from arterial walls); and some other less well known techniques.

Despite the FAA’s more understanding standards toward regaining one’s medical after a CHD diagnosis and treatment, the process is a paper chase of the first degree, one that requires some rigorous medical testing. The pilot’s petition for special issuance requires submission of all records from the initial evaluation and treatment, interim progress notes and the record of a maximal radionucleotide stress test conducted at the end of the six-month observation period.

Radionucleide stress testing involves injecting a radioactive isotope (typically thallium or cardiolyte) into the patient’s vein, after which an image of the patient’s heart becomes visible via a special camera. The radioactive isotopes are absorbed by the normal heart muscle. Nuclear images are obtained in the resting condition, and again immediately following exercise. The two sets of images are then compared.

During exercise, if a blockage in a coronary artery results in diminished blood flow to a part of the cardiac muscle, this region of the heart will appear as a relative “cold spot” on the nuclear scan. This cold spot is not visible on the images that are taken while the patient is at rest (when coronary flow is adequate). Radionucleide stress testing, while more time-consuming and expensive than a simple stress test, greatly enhances the accuracy in diagnosing CHD.

For reinstatement of first- or second-class certification, an angiogram is required six months after the heart event that led to the initial diagnosis. In an angiogram, a flexible catheter or tube is inserted into an artery, usually in the groin area, and guided through the arterial system into the heart and into the coronary arteries. A dye is then injected through the catheter into the bloodstream and X-rays of the heart and coronary arteries are taken. A successful test leads to a special-issuance certification, which will include a requirement of periodic follow-up testing.

As part of its liberalization program, the FAA recently stretched its six-month follow-up testing period to 12 months for first- and second-class medicals, requiring only an examination and stress test at 12 months and moving the radionucleotide test back to 24-month intervals. However, should they so desire, the FAA’s cardiac consultants, upon reviewing an airman’s recertification, can hold an applicant to a schedule of regular six-month tests in the case of first- and second-class medicals and 12 months for third class.

Heart-valve replacement or repair–All three classes of pilot are allowed to fly again following replacement or repair of just one valve. Again, a six-month observation period (and consequent suspension of flying privileges) is required. At the end of that period, the FAA requires a clinical status report from the supervising physician(s); electro-cardiogram; echocardiogram (a non-invasive test combining a stress test with an echocardiogram, a procedure using ultrasound to provide an image of the heart’s internal structures, size and movement); and a Holter monitor (this produces a continuous, 24-hr electrocardiographic recording of the heart’s rhythm. Electrodes are placed on the chest area, with the leads attached to a small recorder. The patient keeps a 24-hr diary to record daily activities and any symptoms experienced. Holter monitoring helps doctors evaluate the type and amount of irregular heartbeats during regular activities, as well as exercise and sleep.)

Multiple heart-valve replacement– Except for a type of surgery known as a Ross procedure, the FAA does not certify pilots with multiple heart-valve replacements. In the Ross procedure, the patient’s pulmonic valve is transplanted to replace a defective aortic valve. The place formerly occupied by the pulmonic is filled with an artificial valve. Since only one valve is new to the patient, the Ross procedure is not, strictly speaking, a double replacement.

Anticoagulation therapy–Easing the burden on the heart, a broad range of anticoagulation therapies “thin the blood,” a not entirely accurate description of the process at work. Anticoagulants lessen the danger of life-threatening blood clots forming as a result of heart surgeries, the implantation of artificial heart valves and so forth. In his recently issued statement, Dr. Silberman stated an overall policy in which the aeromedical certification process would look at anticoagulation therapies much more critically than before throughout a broad range of conditions, most of them having to do with patterns of irregular heartbeat. For lower-risk patients below the age of 65, aspirin therapy is the preferred technique, while those more seriously afflicted and above the age of 65 require warfarin, the generic name for an effective anticoagulant sold widely under the brand name of Coumadin.

Pacemaker–In much the same way that the bank offers to lend you money only when you don’t need it, pilots can be granted all classes of aeronautical certification after they are fitted with a pacemaker, provided they show no evidence of being dependent on it. But what constitutes “dependency?” A heart rate that drops to less than 40 beats per minute or symptoms of lightheadedness or chest discomfort when the pacemaker is turned off. Should that be the case, the FAA will not issue either a first- or second-class medical. Third-class special-issuance certificates are an aviator’s only alternative under these conditions. A new ruling from the FAA holds pilots to a two-month observation period following implantation of a pacemaker, down from the previous six-month minimum.

Automatic internal cardiac defibrillators (AICD)–A new technology in which a tiny defibrillator is implanted in a patient susceptible to potentially fatal heart-rhythm disturbances requiring immediate electrical attention. External defibrillators are a well known part of today’s landscape and have saved thousands of lives. Given the newness of the technology, the FAA does not now approve AICDs for any class of airman use, but admits that this policy is currently under review.

Hypertrophic cardiomyopathy– Essentially a thickening of the heart muscle, this condition is also known as “asymmetric septal hypertrophy,” “idiopathic hypertrophic subaortic stenosis,” and “muscular subaortic stenosis.” The risk from all is sudden death, particularly (and most ironically) in connection with exercise. The FAA will not grant special authorizations to pilots with this condition and immediately grounds those so affected, making this illness one of the few that carries with it an automatic disqualification.