Here in a nutshell is a demonstration of the problem with expecting technology to substitute for good clinical medicine and save us from our self-destructive addictions. If anyone is puzzled about the dichotomy between the exorbitant cost of the US medical system and its relative lack of effect on any measure of health here is the reason.
Below is a story from theheart.org followed by the actual paper in the Archives of Internal Medicine minus the references.
In the absence of any symptoms attributable to coronary artery disease there was no reason to do any more testing but the temptation to use high tech tools without good indication is irresistible to many doctors. CCTA is the latest expensive test to detect coronary atherosclerosis. Patients think that they will never have a heart attack and live longer if the disease is detected and some surgical procedure, like an angioplasty or bypass is done and doctors making $millions from doing them are not about to discourage them and point out the total lack of evidence for any significant benefit from angiography or the surgical procedures in patients with chronic coronary disease.
The authors have labelled this patient “low risk” because her “cholesterol” was normal but clearly she was at high risk based on her obesity and hypertension, both indices generally of junk food addiction, in spite of her being a nurse. When she started new exercises she probably got muscle pain from weight lifting. With an obvious self-destructive lifestyle, she should not have been “simply reassured” as recommended by the editors. But instead of encouraging her to make meaningful lifestyle change her doctors ordered tests with no clinical indication.
Framingham scores, lipid profiles and CRPs can be very deceptive because they do not assess LDL modification in the arterial wall, essential to the formation of atherosclerotic plaque. In spite of having “normal” numbers for all the usual “risk factors” she had advanced atherosclerosis in her coronary arteries. Apparently no dietary history was taken and no attempt was made to encourage her to change her lifestyle, an example of gross diagnostic and therapeutic incompetence, all too common in an era of absolute faith in the power of technology to protect us from our self-destructive addictions. Doctors abdicate professionalism by ordering tests instead of dealing with the real problems, like junk food addiction, which take much time for which they are not compensated and risk alienating patients who demand a high-tech fix or reassurance so that they can continue their risky behaviour.
Case study shows how “just-in-case” CCTA in a low-risk patient may spectacularly backfire
DECEMBER 17, 2010 | Reed Miller
San Francisco, CA – Coronary computed tomographic angiography (CCTA) in patients with a low pretest risk of coronary disease wastes resources and can even lead to horrendous outcomes, a case study published December 13, 2010 in the Archives of Internal Medicine shows. The report tells the story of a 52-year-old white female who initially presented with chest pain and had a CCTA; this was followed by an unfortunate chain of events in which she suffered an aortic dissection during cardiac catheterization and that culminated in her having a heart transplant.
Part of its ongoing “Less is More” series begun last April, the latest case, reviewed by Dr Matthew Becker (St Vincent’s Heart and Vascular Institute, Erie, PA), Dr John Galla (Providence Hospital, Mobile, AL), and Dr Steven Nissen (Cleveland Clinic, OH), describes how the well-meaning attempt to reassure a patient with a low risk of coronary disease backfired spectacularly.
“Perhaps the most important point to be learned from the case described by Becker and colleagues is that there are safer ways to reassure patients,” say journal editors Drs Rita Redberg, Mitchell Katz, and Deborah Grady (University of California, San Francisco) in an accompanying editorial. “Patients value our advice. Talking with our patients should be our first choice for reassurance.” They add that “applying the ‘less-is-more’ principles prospectively could have avoided this unfortunate case.”
From diagnostic uncertainty to disaster
The 52-year-old nurse had hypertension and mild obesity and had recently begun an exercise and diet regimen to control her weight and blood pressure. She presented to her primary physician with chest pain, but no other symptoms: she had a normal ECG with a normal lipid profile and normal C-reactive-protein level. Her doctor attributed the chest pain to a musculoskeletal cause but performed a CCTA to reassure her that she was not at risk for a coronary event.
The CCTA showed discrete, noncalcified, nonobstructive plaque in the mid and distal segments of the left circumflex and dominant right coronary arteries and diffuse, complex calcification in the proximal left anterior descending (LAD) coronary artery. Because that calcification was difficult to quantify, the physician recommended that she undergo cardiac catheterization to get a clearer look at the LAD.
This exam, performed at the local community hospital, revealed only a mild irregularity in the LAD, but during the procedure, the patient complained of chest pressure, which prompted an aortogram that revealed an aortic root dissection that was compromising the left main coronary artery.
So the patient underwent urgent coronary artery bypass graft (CABG) surgery and stayed in the hospital for two weeks with a residual left ventricular ejection fraction of 35%. The bypass graft soon failed and was treated with multiple drug-eluting stents, but despite her compliance with dual antiplatelet medical therapy, a stent in the vein graft supplying the circumflex artery developed a thrombosis, causing an ST-segment-elevation MI complicated by cardiogenic shock. The thrombosis was successfully treated, but the patient remained in refractory cardiogenic shock and ultimately underwent orthotopic heart transplantation.
Unnecessary testing happening every day
“With few cardiac risk factors and an atypical chest pain presentation, this patient had a low pretest probability for coronary artery disease and should have been reassured and not undergone any further risk stratification,” say the authors. “Lacking randomized data suggesting improvement in clinical outcomes and with clear risks, including contrast load, radiation exposure, and suboptimal diagnostic specificity, CCTA should have a very limited role in the evaluation of patients who present with chest pain.”
They acknowledge the risk of complications associated with cardiac catheterization is low, but catastrophic events are always a possibility. They believe the physicians in this case overestimated the stenosis in this patient’s coronaries because they did not fully appreciate the CCTA’s potential for false-positive findings. Complete visualization of all segments of the coronary tree with CCTA is often hindered by cardiac motion, which can lead to the appearance of “blooming artifacts” of coronary calcification that may cause the observer to overestimate the extent of stenosis.
Becker et al point out that previous studies comparing CCTA with conventional coronary angiography in diverse patient populations show CCTA’s sensitivity is between 79% and 100% for the detection of obstructive coronary disease, but its specificity is only 64% to 85%, corresponding to “an unacceptably high false-positive rate” of up to 81% in some populations.
As reported by heartwire, the recently released professional guidelines on Appropriate Use Criteria for Cardiac Computed Tomography list CCTA as “inappropriate” for detection of CAD patients with a low risk of heart disease, ability to exercise, nonacute symptoms that may be an “ischemic equivalent,” and an interpretable ECG.
Patient could have been simply reassured
“If a test is not sufficiently accurate to change clinical management in a particular setting, it should not be done,” but according to Redberg et al, often these tests are done anyway—sometimes even before the patient sees a physician—because nobody has assessed the patient’s pretest probability of the disease or properly considered how the test result will change the clinical management of the patient.
“There are cases where [the test presents] more risks than benefits, and you really need to consider the risks and benefits and not [assume that] just because you can do the test, you should do the test. And this case highlights that,” Redberg told heartwire.
Cases like this where an inappropriate test leads to many complications and near catastrophe are rare, “but to have a CT or another test that was just done for reassurance, when you could have just told the patient ‘You’re fine,’—I think that’s done every day lots of times.
“You don’t know which [tests] are going to lead to that kind of problem, but you do know which of those is not going to give you any benefit, so if there is no benefit, it’s better not to be taking any risk, even a small one.”
Left Main Trunk Coronary Artery Dissection as a Consequence of Inaccurate Coronary Computed Tomographic Angiography
Arch Intern Med. Published online December 13, 2010. doi:10.1001/archinternmed.2010.464
A 52-year-old woman presented to a community hospital with atypical chest pain. Her low-density lipoprotein cholesterol and high-sensitivity C-reactive protein levels were not elevated. She underwent cardiac computed tomography angiography, which showed both calcified and noncalcified coronary plaques in several locations. Her physicians subsequently performed coronary angiography, which was complicated by dissection of the left main coronary artery, requiring emergency coronary artery bypass graft surgery. Her subsequent clinical course was complicated, but eventually she required orthotropic heart transplantation for refractory heart failure. This case illustrates the hazards of the inappropriate use of cardiac computed tomography angiography in low-risk patients and emphasizes the need for restraint in applying this new technology to the evaluation of patients with atypical chest pain.
REPORT OF A CASE
A 52-year-old white female nurse with a medical history that was notable for hypertension and mild obesity presented to her local primary care physician with the recent onset of chest pain. Further investigation revealed that in an effort to lose weight and assist in the control of her hypertension, she had adopted a new diet and exercise program several weeks earlier. At her initial presentation, she described 48 hours of nonexertional, sharp chest pain that was aggravated by elevation of her right arm and deep inspiration. She denied associated symptoms of shortness of breath, nausea, vomiting, or diaphoresis, and her office electrocardiogram showed no abnormalities.Other than mild hypertension (blood pressure, 142/85 mm Hg), the results of her physical examination were unremarkable except that elevation of her right arm and palpation of the right chest wall reproduced the symptoms with which she presented. With a normal lipid profile and an ultrasensitive C-reactive protein level, she was diagnosed as having atypical chest pain most likely of musculoskeletal origin. Hydrochlorothiazide was used to treat her hypertension, and cardiac computed tomography angiography (CCTA) was performed to exclude the possibility of coronary artery stenosis and to reassure her. Interpretation of the CCTA findings suggested that both the left circumflex and the dominant right coronary arteries had discrete areas of mild, noncalcified, nonobstructive plaque in their mid and distal segments. The large-caliber left anterior descending coronary artery (LAD) was reported to have diffuse and complex calcification of the proximal segment, which made accurate quantification of the luminal stenosis challenging.
Subsequently, the patient’s physician recommended cardiac catheterization to enable more precise assessment of the LAD luminal stenosis. Selective coronary angiography was performed at the local community hospital and revealed only a mild luminal irregularity of the LAD. Shortly after the second injection of contrast, the patient complained of intense chest pressure and was noted to be hypotensive and tachycardic (blood pressure, 78/45 mm Hg; heart rate, 110/min). Mild “staining” of contrast was noted in the left coronary cusp of the aorta, and an ascending aortogram revealed a dissection of the aortic root extending into, and resulting in compromise of, the left main coronary artery. An intra-aortic balloon pump was placed, and the patient underwent urgent coronary arterybypass with saphenous vein grafting of both the LAD and the left circumflex coronary artery.
Following a prolonged, 14-day hospital course and a residual left ventricular ejection fraction of 35%, the patient was discharged home with intensive cardiac rehabilitation. Unfortunately, within 6 months of the bypass, she presented again with escalating chest pain and was noted have premature graft failure that was treated with percutaneous coronary intervention with multiple drug-eluting coronary stents. Despite her compliance with dual antiplatelet medical therapy (aspirin and clopidogrel daily), she presented 8 weeks later with an ST-segment elevation myocardial infarction complicated by cardiogenic shock. Emergent catheterization revealed thrombosis of the stent in the vein graft supplying the circumflex artery that was successfully treated with a catheter-based intervention. However, the patient remained in refractory cardiogenic shock and ultimately required urgent orthotopic heart transplantation.
Emergency department visits for chest pain syndromes represent a large and growing health care burden. Because patients with chest pain require urgent triage and timely management, there are great incentives for developing a new generation of novel, complementary diagnostic strategies. A recent addition to the diagnostic armamentarium, multidetector CCTA, can noninvasively generate reconstructed images of the coronary circulation. However, the brisk expansion and rapid adoption of CCTA over the past decade has outpaced supportive clinical data and has led to the referral of a much larger, and often lower-risk, segment of the population for coronary artery catheterization. We believe that in this case the unwarranted use of advanced diagnostic imaging (false-positive CCTA findings) directly contributed to unnecessary cardiac catheterization that resulted in a tragic complication and significant morbidity.Advanced diagnostic imaging technologies or the latest biomarker cannot, and should not, replace a thorough history and physical examination with subsequent decision making guided by the bestevidence-based practice. The need for testing in patients with chest pain is based on the clinician’s estimation of the pretest probability of coronary disease. In a patient with a low pretest probability (<10%) of having significant coronary disease, the preferred course is to reassure the individual and to focus the treatment plan on primary or secondary prevention strategies. Additional diagnostic testing rarely garners useful information and exposes the patient to unnecessary risk—both from the diagnostic test itself and from subsequent invasive testing because of false-positive results. While the risk of complications associated with cardiac catheterization is low, catastrophic events can occur. As opposed to CCTA, in appropriately selected patients coronary angiography allows the presence, location, and, most importantly, the functional significance (eg, fractional flow reserve, intravascular ultrasonography) of lesions to be determined. Because there is often discordance between luminal stenosis and the physiologic significance of lesions, functional testing has assumed critical importance in the assessment of patients with a moderate pretest probability (10%-90%) of coronary disease.
Therefore, given the possible adverse consequences of the overuse of diagnostic imaging in a broad and uncensored population of patients with chest pain, recent joint professional guidelines emphasize that ” . . . an appropriate imaging study is one in which the expected incremental information, combined with clinical judgment, exceeds the expected negative consequences by a sufficiently wide margin for a specific indication that the procedure is generally considered acceptable care and a reasonable approach for the indication. . . . “Furthermore, because of differences in body habitus, coronary physiology, exercise physiology, symptom presentation, and disease prevalence, the diagnostic accuracy of stress testing may be affected by the female sex. In addition to having a markedly different ST-segment response to exercise from a young age, data suggest that ST-segment depression tends to be less sensitive and specific for coronary artery disease in women. With normal electrocardiographic findings, negative cardiac biomarkers, and a classically atypical presentation, our patient had an age-specific risk level that was below average. She had a low pretest probability of coronary disease (<10% risk of myocardial infarction or death per 10 year interval), making further testing inappropriate and the chance of false-positive study results unacceptably high. However, in an era of rapid advancement in diagnostic imaging strategies, the savvy clinician must not forget the basic tenets of data-driven medicine, patient selection, and risk tolerance and ultimately realize when less may be more. Such is precisely the case with CCTA.
Because CCTA is rapid and noninvasive and has wide availability, it has increasingly been used to detect coronary atherosclerosis in a broad array of patient populations. However, the lack of randomized data suggesting clinical benefit, as well as technical and anatomical limitations, restricts its application in many patients. Studies comparing CCTA with conventional coronary angiography in diverse patient populations suggest that CCTA is highly sensitive (79%-100%) for the detection of obstructive coronary disease, with a positive predictive value ranging from 86% to 91%. However, these same studies report suboptimal specificity (64%-85%) and negative predictive values of 83% to 90% that correspond to an unacceptably high false-positive rate of up to 81% in selected subpopulations. Further limiting the diagnostic accuracy of CCTA is the fact that complete visualization of all segments of the coronary tree is hindered by cardiac motion (heart rate, >70/min), smaller vessel caliber (<2 mm), and tortuousity that may result in portions of a vessel moving in and out of an imaging plane. Furthermore, given its high attenuation coefficient, the presence of coronary calcification commonly produces a “blooming artifact” that makes accurate assessment of adjacent arterial luminal challenging and may result in overestimation of the degree of luminal stenosis, which is likely the case in the patient described herein. Therefore, CCTA often overestimates the presence and severity of coronary atherosclerosis to a degree that is dependent on the study population, the equipment used, and the experience of the interpreting physician, which may lead to unnecessary, higher-risk, and costly invasive procedures.
Nevertheless, the use of CCTA has increased dramatically over the past decade, with some estimates suggesting up to 26% per year. In an era in which comparative efficacy of therapies has assumed critical importance, the unchecked growth of CCTA seems not only unfounded but also irresponsible and unsustainable. Aside from its cost implications, CCTA also exposes the patient to substantial amounts of ionizing radiation. It is estimated that the collective dose received from medical radiation increased by more than 700% between 1980 and 2006, with increases in computed tomography accounting for more than 50%. Furthermore, 64-slice CCTA (without tube current modulation) exposes the patient to an average effective dose of 15 mSv of radiation compared with only 7 mSv for diagnostic coronary angiography. With recent data suggesting that 1.5% to 2.0% of all reported cancers in the United States may be linked to ionizing radiation from computed tomography, there is reason for pause.
In conclusion, our patient suffered a rare but devastating complication from an cardiac catheterization that was the direct result of unnecessary CCTA and false-positive findings. With few cardiac risk factors and an atypical chest pain presentation, this patient had a low pretest probability for coronary artery disease and should have been reassured and not undergone any further risk stratification. Lacking randomized data suggesting improvement in clinical outcomes and with clear risks including contrast load, radiation exposure, and suboptimal diagnostic specificity, CCTA should have a very limited role in the evaluation of patients who present with chest pain.