Are the American College of Cardiology/American Heart Association guidelines for exercise testing for suspected coronary artery disease correct?

An investigation of dentists' and dental students' estimates of diagnostic probabilities

BACKGROUND

Research in medicine has shown that physicians have difficulty estimating the probability that a patient has a condition on the basis of available diagnostic evidence. They consistently undervalue baseline information about the patient relative to test information and are poor intuitive calculators of probability. The authors could not locate in the literature any studies of diagnostic probability estimates from baseline information and test data for dentists.

METHODS

Using two vignettes that contained different baseline information, dental students and clinical faculty members estimated the probability that the described hypothetical patient had the condition in question. Respondents also commented on the project.

CONCLUSIONS

Both groups of respondents overemphasized the importance of test evidence relative to baseline information, although experienced practitioners did so to a lesser extent than did students. Respondents, especially practitioners, expressed resistance to performing a diagnostic task that required precise estimates of probability.

CLINICAL IMPLICATIONS

Dentists appear to estimate diagnostic probabilities in an intuitive fashion, but they do so imprecisely. Clinical experience provides some protection against the bias of overestimating test evidence compared with baseline information. These findings raise questions about how practitioners use probability estimates and whether other models also may play a role. The incorporation of information from evidence-based dentistry into practice requires better understanding.

Clinical implication of adenosine-stress cardiac magnetic resonance imaging as potential gatekeeper prior to invasive examination in patients with AHA/ACC class II indication for coronary angiography

BACKGROUND

Real world cardiology is faced with a low diagnostic yield of coronary angiography (CXA) in patients presenting with ACC/AHA class II CXA indication. Our aim was to analyze the clinical implication of a Cardiac MR (CMR) protocol including adenosine stress perfusion in this patient population. We examined whether CMR could enhance appropriate CXA indication and thus reduce the rate of pure diagnostic CXA. In addition, we compared the relative impact of CMR exam components (perfusion, function and viability assessment) in achieving this target.

METHODS

176 patients were referred for CXA with class II indication. 171 underwent complete additional CMR exam in a 1.5-T whole body CMR-scanner for myocardial function, ischemia and viability prior to CXA. The routine protocol for assessment of CAD consisted of functional imaging (long and short axes), adenosine stress- and rest-perfusion in short axis orientation and "late enhancement" imaging in long and short axes. Images were analyzed by two independent and blinded investigators. Interobserver differences were resolved by a third reader.

RESULTS

There was a high association between CMR results and subsequent invasive findings (chi square for CMR perfusion deficit and stenosis >70% in CXA: 113.7, p<0.0001). 109 (63.7%) of our patients had relevant perfusion deficits as seen by CMR and matching coronary artery stenosis >70%. Four (2.3%) patients had false negative CMR findings. In 58 patients (33.9%) no relevant coronary artery stenosis could be observed, correctly predicted by CMR in 48 cases; in 10 (5.8%) patients CMR provided false positive results. Sensitivity of CMR to detect relevant CAD (>70% luminal narrowing) was 0.96, specificity 0.83, positive predictive value 0.92 and negative predictive value 0.92. Of the CMR components, perfusion deficit was the strongest independent predictor (odds ratio 132.3, p < 0.0001).

CONCLUSION

In a great number of patients being referred to cath lab with ACC/AHA class II indication for CXA, CMR provides a high accuracy for decision making regarding appropriateness of the invasive exam. CMR prior to CXA could substantially reduce pure diagnostic coronary angiographies in patients with intermediate probability for CAD, in our patient-cohort from approximately 34% to 6%. Further studies are warranted to identify rare false negative CMR results.

Exertional headache and coronary ischemia despite normal electrocardiographic stress testing

Exertional headaches may under certain conditions reflect coronary ischemia. We report the case of a patient seen in a neurology referral practice whose exertional headaches, even in the face of two normal electrocardiographic stress tests and in the absence of underlying chest pain were the sole symptoms of coronary ischemia as detected by Tc-99m Sestamibi testing SPECT stress testing. Stent placement resulted in complete resolution of headaches. Exertional headache in the absence of chest pain may reflect underlying symptomatic coronary artery disease (CAD) even when conventional electrocardiographic stress testing does not indicate ischemia.

Prevalence of esophageal disorders in patients with recurrent chest pain

The objective of this study is to determine the prevalence of esophageal disorders (ED) associated with recurrent chest pain (RCP) and the utility of esophageal functional tests (EFT) in the study of these patients. The cross-sectional study was conducted at Hospital Clínico de La Frontera, Chile. One hundred and twenty-three patients with RCP were studied using esophageal manometry, edrophonium stimulation and 24-h pH monitoring. The performance of EFT was considered acceptable when they were capable of finding ED. To state the probability that RCP had an esophageal origin, patients were classified according to whether their pain had a probable, possible or unlikely esophageal origin. The prevalence of ED was determined according to diagnoses obtained after applying EFT and a multivariate analysis was performed to examine the association between the esophageal origin of RCP and ED. Rates of correct diagnosis of 65.9%, 56.9% and 31.7% was verified for 24-h pH monitoring, esophageal manometry and edrophonium stimulation, respectively. In 38.2% of patients with RCP, the pain was probably of esophageal origin, in 42.3% there was a possible esophageal origin and in 19.5% an unlikely esophageal origin. A 44.7% prevalence of GERD, 26.8% of GERD with secondary esophageal motor dysfunction and 8.9% of pure esophageal motor dysfunction were verified. The multivariate analysis allowed us to verify the association between the probability of esophageal origin of RCP, the variables RCP duration, esophagitis and dysphagia coexistence (P= 0.037, P= 0.030 and P= 0.024, respectively), and a statistically significant association between ED and dysphagia coexistence (P= 0.028). A high prevalence of ED was identified in patients with RCP.

Evaluation of pretest and exercise test scores to assess all-cause mortality in unselected patients presenting for exercise testing with symptoms of suspected coronary artery disease

OBJECTIVES

To determine how well recently developed multivariables scores assess for all-cause mortality in patients with suspected coronary disease presenting for exercise electrocardiography (ExECG).

BACKGROUND

Recently revised American College of Cardiology/American Heart Association guidelines for ExECG have suggested that ExECG scores be used to assist in management decisions in patients with suspected coronary artery disease. Recently developed scores accurately stratify patients according to angiographic disease severity.

METHODS

To determine how well these scores assess for all-cause mortality, we utilized 4,640 patients without known coronary disease who underwent ExECG to evaluate symptoms of suspected coronary disease between 1995 and 2001. Previously validated pretest and exercise test scores as well as the Duke treadmill score were applied to each patient. All-cause mortality was our end point.

RESULTS

Overall mortality was 3.0% with 2.8 +/- 1.6 years of follow-up. All three scores stratified patients into low-, intermediate-, and high-risk groups (p < 0.00001). No differences were seen when patients were evaluated as subgroups according to gender, diabetes, beta-blockers, or inpatient status. Low-risk patients defined by the Duke treadmill score had consistently higher mortality and absolute number of deaths compared with low-risk patients using other scores. In addition, the Duke treadmill score had less incremental stratifying value than the new exercise score.

CONCLUSIONS

Simple pretest and exercise scores risk-stratified patients with suspected coronary disease in accordance with published guidelines and better than the Duke treadmill score. These results extend to diabetics, inpatients, women, and patients on beta-blockers.

Development and validation of a simple exercise test score for use in women with symptoms of suspected coronary artery disease

BACKGROUND

Recently revised American College of Cardiology/American Heart Association guidelines for exercise electrocardiography (ExECG) have suggested that ExECG scores be used to assist in management decisions in patients with suspected coronary artery disease (CAD).

METHODS

We used 442 women who underwent both ExECG and coronary angiography (CAD > or =1 lesion with > or =50% stenosis; CAD prevalence was 32%) to derive an ExECG score including clinical and ExECG variables. By use of logistic regression analysis, variables were selected and relative weights were determined. Variable codes multiplied by respective weights were summed to produce a final ExECG score. The score was validated in separate populations concerning angiographic as well as prognostic end points.

RESULTS

Clinical variables selected and their weights included age (5), symptoms (2), diabetes (2), smoking (2), and estrogen status (1). ExECG variables selected and their weights included ST depression (2), exercise heart rate (4), and Duke Angina Index (3). For the validation group, score ranges are shown with the prevalence of CAD: <20 = 0/5 or 0%, 20-29 = 3/26 or 11%, 30-39 = 20/56 or 36%, 40-49 = 33/81 or 41%, 50-59 = 24/49 or 49%, 60-69 = 22/32 or 69%, and >70 = 7/7 or 100%. Frequency of death within 3 predetermined subgroups was as follows: low <40 = 3/1237 (0.2%), intermediate 40-60 = 9/383 (2.3%), high >60 = 4/54(7%); P<.0001.

CONCLUSION

A simple ExECG score was developed for use specifically in women. When evaluated in separate cohorts, the score stratified women with suspected coronary disease into groups with a gradually increasing frequency of coronary disease and death.