A Shower of Little Clots

When leading heart specialists from the U.S. and Europe gathered in New Orleans last week, the first and most significant report they heard was not exclusively about heart disease. A visitor from England re-emphasized some of the difficulties of diagnosing a lung disorder that has its origins in the blood vessels and eventually involves the heart.

There is no common name for what Dr. John F. Goodwin of the University of London and Hammersmith Hospital called "thromboembolic pulmonary vascular disorders." But these disorders, Dr. Goodwin told the Louisiana Heart Association and the American College of Cardiology, are extremely common. In their most dramatic and catastrophic form, they are called pulmonary embolisms, and they may be almost as common as the single heart attack that proves quickly fatal. Their mechanism is similar--a blood clot traveling through the veins, usually from a leg, blocks one of the great arteries carrying blood from the heart to the lungs--and their effects are just as deadly.

Sudden Catastrophe. Clot-caused obstructions in the smaller arteries of the lungs are even more common. But they are less often recognized because their onset is insidious and they are harder to diagnose. This kind of lung disorder is different from the familiar bronchitis and emphysema, Dr. Goodwin emphasized. In those diseases, the trouble is in the air passages or the air spaces of the lungs themselves. With clotting obstructions, the trouble originates in the blood vessels. But in the long run, it has just as serious effects on breathing.

The sudden, catastrophic form of embolism is marked by severe pain in the chest, fever and coughed-up blood. Often the victim is known to have had some blood-vessel disorder, such as phlebitis. In the creeping insidious form, there is no such history of clotting disease to alert the doctor. The patient usually complains of nothing more precise than shortness of breath or fainting, though in slightly more severe cases he may collapse completely on exertion. What has happened, said Dr. Goodwin, is that small blood clots have blocked some of the narrower blood vessels leading to the lungs. The patient can still inhale and exhale just as much air, but he does not oxygenate enough blood, so he tends to breathe too hard.

Mississippi Metaphor. Post-mortem findings indicate that these patients have suffered from what Dr. Goodwin called "showers of clots." Then, switching to an appropriate Mississippi Delta metaphor, he suggested that their effect is to silt up the channels through which the lungs' blood flows. One result, which should help physicians in diagnosing the disorder, is that the concentration of oxygen in the arterial blood goes down with exertion, and so does the level of carbon dioxide.

Lung-artery disease is most likely to be diagnosed correctly, said Dr. Goodwin, if physicians have a suspicious eye and ear open for it. In difficult cases, a series of electrocardiograms may be decisive. And regardless of difficulty, it is important to diagnose the disorder early --when there is still hope of arresting it with anticoagulants. It probably is never "cured" in the literal sense, and only rarely is it reversed so thoroughly that the patient is freed of his handicap.

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