The high profile case of Rush Limbaugh’s chest pain raises a question that never seems to get a satisfactory answer. Is isolated chest pain an indication for a coronary angiogram? Lets use Mr Limbaugh’s case as an example. Since all I know about it is what he has said, I’ll make some assumptions for the sake of discussion.
A 59 year old man with no history of cardiovascular disease experiences severe chest pain highly suggestive of an acute coronary event. EMS is summoned, he receives emergency treatment, the pain subsides only to reoccur. By the time a physician arrives the second episode of chest pain has subsided. His evaluation is entirely negative. EKG is normal, cardiac enzymes are normal and remain so. Vital signs are normal. He is not diabetic and his blood lipid levels have always been normal. Nevertheless, he is taken to the cath lab and a coronary angiogram is performed which is also normal.
Was the angiogram indicated or was it a reflex conditioned by a combination of habit and defensive medicine? The fear of physicians when someone arrives in the emergency room with chest pain is that he is experiencing an heart attack – or an acute coronary syndrome a term now in vogue.
Below is a table taken from the American College of cardiology/American Heart Association Guidelines for Coronary Angiography. The entire report is here: ACC/AHA Guidelines for Coronary Angiography
Noninvasive Test Results Predicting High Risk for Adverse Outcome
||Severe resting left ventricular dysfunction (LVEF<35%)
||High-risk treadmill score (score-11)
||Severe exercise left ventricular dysfunction (exercise LVEF<35%)
||Stress-induced large perfusion defect (particularly if anterior)
||Stress-induced moderate-size multiple perfusion defects
||Large, fixed perfusion defect with left ventricular dilatation or increased lung uptake (201Tl)
||Stress-induced moderate-size perfusion defect with left-ventricular dilatation or increased lung uptake (201Tl)
||Echocardiographic wall motion abnormality (involving >2 segments) developing at low dose of dobutamine (10 mg · kg-1 · min-1) or at a low heart rate (<120 bpm)
||Stress echocardiographic evidence of extensive ischemia
1 Greater than 3% annual mortality rate.
bpm indicates beats per minute.
Given that our patient is stable, has a normal EKG, and whose initial cardiac enzymes are normal. The next move should not be to take him to the cath lab. Less invasive tests as depicted on the table above should be performed; if they are normal and subsequent cardiac enzymes levels remain unchanged the likelihood of an acute coronary syndrome is just about zero. The patient should be discharged and followed as an outpatient.
Assuming that Mr Limbaugh’s case is as I have described it (a big assumption as I don’t have the details of his case) then his angiogram was unnecessary. So let’s focus on a patient who really does have all the characteristics I have just listed. He would still get a coronary angiogram in many medical centers. Why?
Medicine does not lack scientifically based guidelines for rational clinical practice. But they are commonly ignored. The evaluation and treatment of coronary artery disease is right at the top of diseases that have been exhaustively studied, that have sound diagnostic algorithms, that have effective treatments (both medical and surgical), that are diagnosed and treated on a seat of the pants basis rather than on the basis of medical science.
To a close observer who is not a cardiologist it seems that the diagnosis and treatment of coronary artery disease is like the cost of a flight on American Airlines – no two passengers have paid the same price for their ticket.
The aggressiveness with which one cardiologist approaches a patient with chest pain seems to depend in large part on his personality. Also, medical science is not as precise and clear cut as physics. There is a wide range of practice patterns that fall within the bounds of acceptability. The ultimate standard for the presence of absence of coronary artery disease is the coronary angiogram. So, many cardiologists don’t fool around with non-invasive tests when they have a patient whose story is typical of coronary disease. The patient goes to cath lab. Guidelines are just that – guidelines. They are not graven in marble, at least not yet. But a lot of unnecessary angiograms are performed.
The practice pattern is not likely to change, but coronary angiograms can go wrong. The complication risk from the procedure is low – around 1%. Serious complications are even less common, but they do occur. When you’ve seen a few you get a little less cavalier about sending low risk patients to the cath lab.
And finally, you don’t get sued for telling a patient he doesn’t have coronary artery disease when he doesn’t, but you do get sued for telling a patient he doesn’t have it when he does.