It is very early. I am running to the 'clinical decision unit' (CDU) to see a patient of mine sent in the night before from a local skilled nusing facility. Also known as clinical observation units, 'obs' units, or short stay observation units, these units were designed to help decompress busy emergency rooms and divert unnecessary, expensive inpatient admissions. The units are typically adjacent to emergency departments, and usually are run by emergency physicians. My particular patient was admitted due to an episode of chest pain at her facility. A brief conversation the prior night with the emergency room staff revealed chest pain that clinically was not typical for any of the feared diagnoses of a heart attack, pulmonary embolism or an aortic dissection. An electrocardiogram and cardiac enzymes were also initially unremarkable. Regardless, the patient was elderly and had multiple other comorbidities, and was somewhat confused. I recommended a short stay to allow anything malignant to declare itself.
And so, here I was, at the observation unit, digging through pages upon pages of printed gibberish that clearly had achieved the nirvana stage of meaningful use (for those wondering, that's after stage 3). Ironically, the most useful piece of information lay in a handwritten progress note describing the episode. I could see why the patient had been brought here to be further evaluated, but after 18 hours of negative biomarkers, electrocardiograms, and no recurrence of symptoms, I felt comfortable letting her go back to where she came from. I told the ER staff... who cancelled her stress test. A stress test? Yes, a stress test had been ordered prophylactically. We practice in a climate where every bad outcome has the potential for litigation - malpractice lawyers would have a field day with the case of anyone going to the ER, being discharged without some type of cardiac imaging study, and having a heart attack. My recommendation to discharge the patient shifts the liability of an adverse outcome from the ER squarely on to my shoulders, and thus, poof goes the stress test.
As I get ready to move to the next patient on my list, I'm stopped by one of the ER physicians. There's a 34 year old woman with chest pain in the CDU as well. She also had a brief episode of chest pain the day prior. She had no other medical history, her electrocardiogram was benign, multiple biomarkers were negative. Her symptoms had resolved. She was scheduled to have a CT scan of her coronaries done. Could I take a look?
6 million patients arrive at emergency departments complaining of chest pain. About seventeen percent of them have a real coronary event. Discovering which one of these patients actually has a real coronary event is one of the great clinical challenges that faces physicians. Traditionally, doctors have used the clinical history, an electrocardiogram, and cardiac biomarkers to make a decision about hospitalization and further cardiac testing. The teaching when I was in training was to categorize patients: low risk patients needed reassurance, intermediate risk patients needed some type of a stress test, and high risk patients needed a cardiac catheterization. The hard part, of course, was drilling down to the patient in front of you in the emergency department and getting that label right. The data with this approach was not perfect. The chances of missing a heart attack were 1 in a 1000 (0.1%). Review of these cases by an expert, experienced cardiologist in the majority of these missed diagnoses revealed no errors; the patients just had very subtle findings that the traditional approach was unable to resolve.
Two developments coincided over the last ten years that started to change the landscape of the approach to chest pain patients. The first development was the push by payers to reduce cost - for chest pain patients that meant avoiding admissions to the hospital. Payers started to refuse payments for those patients deemed too low risk for admission to the hospital. Spooked by this, observation units, and protocols to increase patient throughput through these units flourished. It was within this Wild West-like atmosphere that John Wayne, in the form of the coronary computed tomography angiography (CCTA), arrived. CCTA allowed high resolution images of the coronary tree within minutes, and promised an easy straight talkin' yes/no answer with regards to coronary plaque. A negative test effectively ruled out a coronary event, and as a side benefit, also could provide information about clots in the lung and abnormalities of the aorta. One test that took minutes could obviate the need for a hospital admission, and shorten the amount of time spent in the ER because you didn't need to wait for the old cardiac stress test that was only done during daytime hours. It also seemed to satisfy everyone's appetite for zero risk - the promise was that a negative test meant you were absolutely not going to have a heart attack. The clinical history in this brave new world was irrelevant. After all, the traditional approach that focused on talking to patients missed one out of a 1000 patients. Now we could be perfect, and it would save money! The time for irrational exuberance was upon us.
Not surprisingly, coronary CTA's proliferated in ERs. I noticed that patients who ordinarily would get admitted to the hospital, or would merit a cardiology consultation were instead being sent home from the ER after a negative study. The calls from the ER didn't stop though; they changed. Now the calls were for positive coronary CTAs, which some times forced additional testing. After all, the if the CT scan suggested there was something wrong with your heart...it was exceedingly difficult to reassure the patient or myself with only a lowly stethoscope that everything was actually ok.
Clearly,there was no free lunch when it came to CCTA. There was improved efficiency in the ED, but there was an increase in downstream testing and radiation exposure with no decrease in the overall costs of care. Even more troubling, I started noticing patients that I ordinarily would have suggested no testing were also being put in the imaging pathway. The question no longer was if you needed a test, but what test you should get.
In a study (Foy et. al.) comparing no testing with multiple other cardiac imaging modalities that included stress tests and CCTA, low risk patients who received no further cardiac testing had no difference in outcomes. Unfortunately, that wasn't even the worst part. The unfortunate low risk chest pain cohort that did get additional cardiac testing ended up with additional, invasive testing. It was estimated that for every 27 patients who underwent a myocardial perfusion imaging stress test, 1 patient got an unnecessary cardiac catheterization. For every seventy-one patients who underwent a CCTA, 1 patient would require an unnecessary cardiac catheterization. Since there was no difference in outcomes between the two groups, the additional invasive testing was all risk with no benefit.
As the figure above demonstrates, an approach that involved CCTA for all low risk patients with chest pain would result annually in 50,000 unnecessary cardiac catheterizations. Cardiac catheterizations have become incredibly safe, but do involve snaking a catheter into the small arteries that come off of the aorta and feed the heart. Do this enough, and bad things are bound to happen. In contemporary practice the mortality associated with cardiac catheterization is 1 in a 1000. A rare event, to be sure, but that would mean an estimate of 50 healthy people dying annually due to having an unnecessary procedure. To top it off with a giant maraschino cherry, there is nothing to suggest a CT scan-for-all approach would even reduce the rate of missed heart attacks. Recall that Foy et. al., showed no difference in hospitalization for MI regardless of whether low risk patients got some type of cardiac stress/imaging test or not.
While Foy's paper is a retrospective review that is far from definitive, it does fit in with what I see in clinical practice. The well-intentioned desire to cut costs by avoiding inpatient admissions, and improve safety by reducing missed coronary events has not lowered costs, and has not made patients any safer. There certainly are trials that will point to the impressive negative predictive value of coronary CTAs, and the impressive close-to-zero event rate with these tests. These studies are hopelessly flawed. Many of the patients in these trials should have warranted no further testing, and would have been better served with my mother's masala chai - a much better tasting and soothing alternative.
I did take a look at the young woman with chest pain. I could not bring myself to order a CCTA or a stress test. I did recommend a nice cup of masala chai. She remains alive and well to this day.