Most Patients With CVD Can Fly Safely, Says British Society

From Heartwire

Lisa Nainggolan

July 20, 2010 (Exeter, United Kingdom) — Most people with cardiovascular disease who are not critically ill can safely fly on commercial aircraft, the British Cardiovascular Society has concluded in a new report [1]. The document includes "guidance-at-a-glance" and is aimed primarily at general practitioners, lead author Dr David Smith (Royal Devon and Exeter NHS Foundation Trust, Exeter, UK) told heartwire . It will also be "translated" into "even more straightforward" guidance for patients by the British Heart Foundation, he noted.

Smith said this guidance, the first ever from the British Cardiovascular Society, "tries to go through the detail. In general, we've tried to allow people to fly, unless there is a very good reason not to, whereas the way various other people have looked at this is to say, 'Who shall we restrict?' " Of the many existing guidelines on passenger fitness to fly, most include some reference to cardiovascular disorders, but many are contrary in their advice, particularly with reference to the time required between an event or medical procedure and the flight, he said. "In our view, they were not necessarily based on thinking about the underlying processes, and they often do not separate patients out into higher- and lower-risk categories."

A large proportion of the new document is devoted to looking at the underlying effects of the cabin environment and then seeing whether this is likely to produce a deleterious effect on somebody who has existing heart disease, Smith said. "We've tried to support all our recommendations with analysis of the underlying physiology and physics. The overwhelming conclusion is that the cabin environment poses a very little threat. It's not the flying that's the problem. What we try to emphasize is that it's the stability, or instability, of someone's underlying condition that indicates the probability of a spontaneous event occurring while they are in the air."

Minimal Restrictions on Flying for Most With Pacemakers, ICDs

Smith and colleagues explain that the main impact of air travel is the inhalation of air with reduced oxygen content in a pressurized environment, resulting in lower circulating oxygen levels in the blood, known as hypobaric hypoxia. Passengers already at high risk of angina, myocardial infarction, heart failure, or abnormal heart rhythms might be adversely affected by hypoxia, but the blood oxygen levels induced by flying "appear to have little or no adverse circulatory effects," certainly not for short- and medium-haul flights, they state.

The guidance-at-a-glance, which appears in the first two pages of the document, goes into detail about various cardiovascular conditions, and divides each into low, medium, and high risk, with accompanying lay explanations. It then goes on to give advice on flying for each level of that condition. For example, for post-STEMI and NSTEMI, those at low risk are advised that they can fly three days after their event, and those at medium risk can fly after 10 days. However, those at high risk--ejection fraction <40%, signs and symptoms of heart failure, and those awaiting further investigation, revascularization, or device therapy--are advised to "defer travel" until their condition is stable.

After uncomplicated elective PCI, the guidelines state that patients can fly "after two days." Likewise, patients with pacemakers implanted are advised they can fly after two days, unless they have suffered a pneumothorax, in which case they should wait until two weeks after it has fully healed. The same advice applies to those with ICDs, with the added recommendation that they should not fly after the ICD has delivered a shock until the condition is considered stable.

"We hope we've clarified a lot of things that people worry about. Cosmic rays, effects on their pacemakers, for example, have been addressed in some detail," Smith said. "People are concerned about their defibrillators, pacemakers, and stents . . . and we hope this will allay fears and give guidance as to what people should do if they are going to fly and they have underlying heart disease."

Venous Thromboembolism Risk Low

There is also guidance for the avoidance of deep vein thrombosis (DVT) and venous thromboembolism; although a long-haul flight doubles the risk of DVT, it is similar to that incurred during car, bus, or train travel for a similar period, the doctors state. And the absolute risk of DVT for a fit and healthy person is one in 6000 for a flight of more than four hours, they note, pointing out that pilots are at no greater risk than the general population.

Even those at high risk--those who have already had a DVT, recent surgery lasting more than 30 minutes, known thrombophilia, or pregnancy, and those who are obese (BMI>30 kg/m2)--can still fly, provided they consume plenty of fluids, exclude caffeine and alcohol, wear compression stockings, and take a low-molecular-weight heparin, they say. Aspirin is not recommended.

Smith reports no conflict of interest.

References