Noninvasive Stress Testing Research Articles

Cardiac Stress Testing in Women

More women die every year from cardiovascular disease (CVD) than from any other cause. Non-invasive cardiac stress testing is key to timely diagnosis and treatment of CVD. However, providers need to be aware of how testing accuracy differs between men and women. This article reviews the standard non-invasive tests available, the sensitivity and specificity of each test, and how to choose the most appropriate test for female patients. It also discusses several new testing modes on the horizon.

Acute Coronary Syndromes: Diagnosis and Management, Part II

At the most severe end of the spectrum of acute coronary syndromes is ST-segment elevation myocardial infarction (STEMI), which usually occurs when a fibrin-rich thrombus completely occludes an epicardial coronary artery. The diagnosis of STEMI is based on clinical characteristics and persistent ST-segment elevation as demonstrated by 12-lead electrocardiography. Patients with STEMI should undergo rapid assessment for reperfusion therapy, and a reperfusion strategy should be implemented promptly after the patient's contact with the health care system. Two methods are currently available for establishing timely coronary reperfusion: primary percutaneous coronary intervention and fibrinolytic therapy. Percutaneous coronary intervention is the preferred method but is not always available. Antiplatelet agents and anticoagulants are critical adjuncts to reperfusion. This article summarizes the current evidence-based guidelines for the diagnosis and management of STEMI. This summary is followed by a brief discussion of the role of noninvasive stress testing in the assessment of patients with acute coronary syndrome and their selection for coronary revascularization.

DIFFERENTIATING ISCHEMIC VERSUS NON-ISCHEMIC CARDIOMYOPATHY: WHAT IS THE ROLE OF CALCIUM SCORING?

PURPOSE: The differentiation of ischemic (I) versus non-ischemic (NI) cardiomyopathy (CMP) by non-invasive stress testing has been plagued by suboptimal sensitivity and specificity leading to coronary angiography. We used MDCT angiography as gold standard to assess if coronary calcium could be used as a simple screening tool to differentiate I versus NI CMP.

Coronary calcium score and computed tomography coronary angiography in high-risk asymptomatic subjects: assessment of diagnostic accuracy and prevalence of non-obstructive coronary artery disease

The aim of the study was to compare the coronary artery calcium score (CACS) and computed tomography coronary angiography (CTCA) for the assessment of non-obstructive/obstructive coronary artery disease (CAD) in high-risk asymptomatic subjects. Two hundred and thirteen consecutive asymptomatic subjects (113 male; mean age 53.6 +/- 12.4 years) with more than one risk factor and an inconclusive or unfeasible non-invasive stress test result underwent CACS and CTCA in an outpatient setting. All patients underwent conventional coronary angiography (CAG). Data from CACS (threshold for positive image: Agatston score 1/100/1,000) and CTCA were compared with CAG regarding the degree of CAD (non-obstructive/obstructive; </>or=50% lumen reduction). The mean calcium score was 151 +/- 403 and the prevalence of obstructive CAD was 17% (8% one-vessel and 10% two-vessel disease). Per-patient sensitivity, specificity, positive and negative predictive values of CACS were: 97%, 75%, 45%, and 100%, respectively (Agatston >or=1); 73%, 90%, 60%, and 94%, respectively (Agatston >or=100); 30%, 98%, 79%, and 87%, respectively (Agatston >or=1,000). Per-patient values for CTCA were 100%, 98%, 97%, and 100%, respectively (p < 0.05). CTCA detected 65% prevalence of all CAD (48% non-obstructive), while CACS detected 37% prevalence of all CAD (21% non-obstructive) (p < 0.05). CACS proved inadequate for the detection of obstructive and non-obstructive CAD compared with CTCA. CTCA has a high diagnostic accuracy for the detection of non-obstructive and obstructive CAD in high-risk asymptomatic patients with inconclusive or unfeasible stress test results.

Cardiovascular complications of obesity surgery in patients with increased preoperative cardiac risk

Background Obesity surgery reduces the incidence of long-term cardiovascular events by modifying the associated risk factors. The derived benefits of weight loss surgery might be counterbalanced by the increased cardiovascular risks in some patients. The primary objective of the present study was to determine the rate of cardiovascular events after obesity surgery in patients considered to have an increased cardiac risk profile at a tertiary referral hospital. Methods A retrospective analysis of the data from consecutive patients who underwent obesity surgery at the Cleveland Clinic Florida was performed. The use of β-blockers, noninvasive stress testing, and perioperative events were assessed. Results The data from 154 patients who had undergone a preoperative cardiac consultation at the Cleveland Clinic Florida before obesity surgery from 2003 to 2006 were analyzed. Most patients were women (n = 108, 69%), and 25 (16%) were >65 years old. The number of patients who received perioperative β-blockers was 72 (47%). Noninvasive stress testing was performed in 78 patients (50%). Of the 78 patients who underwent noninvasive stress testing, 25 (32%) had a positive finding. Only 1 patient with positive stress test results had an obstructive coronary artery lesion found on cardiac catheterization. A total of 5 nonfatal cardiac-related events (3.2%) occurred. The in-hospital mortality rate was 0%. Conclusion Obesity surgery in patients with established coronary heart disease or risk factors is a safe and well-tolerated procedure, with an overall low rate of cardiac events. Noninvasive stress testing in this population resulted in a high rate of false-positive results and uncommonly led to intervention.

Noninvasive stress testing of myocardial perfusion defects: head-to-head comparison of thallium-201 SPECT to MRI perfusion

BackgroundTo evaluate the diagnostic value of magnetic resonance imaging (MRI) of myocardial perfusion in the assessment of flow-limiting epicardial stenosis in a head-to-head comparison with abnormal thallium-201 (201TI) single photon emission tomography (SPECT) studies in patients with predominantly known coronary artery disease (CAD). Methods and ResultsTwenty-one patients (mean age 65 ± 10 years) with reversible myocardial perfusion defects on 201TI-SPECT images during dipyridamole-stimulated hyperemia were recruited for study purpose. Within 5 days of the 201TI-SPECT study, myocardial perfusion was studied again with MRI during dipyridamole stimulation and at rest. Overall, 201TI-SPECT identified 30 reversible regional perfusion defects. The sensitivity to detect hypoperfused segments was 70% (21/30) with the GRE-MRI perfusion analysis with 201TI-SPECT as reference. When patients were subgrouped according to the extent of regional reversible perfusion defects on 201TI-SPECT, mild- (SDS: 2-4), moderate- (SDS: 5-8), and severe- (SDS > 8) perfusion defects were also identified by GRE-MRI perfusion analysis in 75% (6/8), in 56% (9/16) and 100% (6/6), respectively. ConclusionsGRE-MRI first-pass stress perfusion imaging may not identify up to 30% of mild-to-moderate perfusion defects in a group of preselected patients with predominantly known CAD and abnormal 201TI-SPECT studies.

Cardiovascular risk assessment of the diabetic patient undergoing major noncardiac surgery

Noncardiac surgery is associated with an increased risk for cardiovascular morbidity and mortality. It is important to stratify the risk of these patients for perioperative cardiac events. Diabetes, a presently rapidly expanding disease, is a major risk factor for cardiovascular morbidity and mortality. Importantly, silent ischemia is more common in diabetic patients than in the general population. When preoperative risk assessment identifies an increased risk, further cardiac testing is warranted. The most commonly used stress tests for detecting cardiac ischemia is treadmill or bicycle ergometry. However, patients undergoing noncardiac surgery frequently have limited exercise capacity due to co-morbidities. Pharmacologic testing, such as dobutamine stress echocardiography and dipyridamole myocardial perfusion scintigraphy can be performed in patients with limited exercise capacity. Non-invasive stress testing should be considered, especially in diabetic patients, to detect asymptomatic coronary artery disease. Furthermore, when an increased cardiac risk is assessed, two strategies could be used to reduce the incidence of perioperative cardiac events: 1) prophylactic coronary revascularization from which the value is still controversial, and 2) pharmacological treatment (with beta-blockers, statins and aspirin), associated with improved post-operative outcome.

Frequency of Acute Coronary Syndrome in Patients with Normal Electrocardiogram Performed during Presence or Absence of Chest Pain

The authors hypothesized that patients with active chest pain at the time of a normal electrocardiogram (ECG) have a lower frequency of acute coronary syndrome (ACS) than patients being evaluated for chest pain but with no active chest pain at the time of a normal ECG. The study objective was to describe the association between chest pain in patients with a normal ECG and the diagnosis of ACS. This was a prospective observational study of emergency department (ED) patients with a chief complaint of chest pain and an initial normal ECG admitted to the hospital for chest pain evaluation over a 1-year period. Two groups were identified: patients with chest pain during the ECG and patients without chest pain during the ECG. Normal ECG criteria were as follow: 1) normal sinus rhythm with heart rate of 55-105 beats/min, 2) normal QRS interval and ST segment, and 3) normal T-wave morphology or T-wave flattening. "Normal" excludes pathologic Q waves, left ventricular hypertrophy, nonspecific ST-T wave abnormalities, any ST depression, and discrepancies in the axis between the T wave and the QRS. Patients' initial ED ECGs were interpreted as normal or abnormal by two emergency physicians (EPs); differences in interpretation were resolved by a cardiologist. ACS was defined as follows: 1) elevation and characteristic evolution of troponin I level, 2) coronary angiography demonstrating >70% stenosis in a major coronary artery, or 3) positive noninvasive cardiac stress test. Chi-square analysis was performed and odds ratios (ORs) are presented. A total of 1,741 patients were admitted with cardiopulmonary symptoms; 387 met study criteria. The study group comprised 199 males (51%) and 188 females (49%), mean age was 56 years (range, 25-90 years), and 106 (27%) had known coronary artery disease (CAD). A total of 261 (67%) patients experienced chest pain during ECG; 126 (33%) patients experienced no chest pain during ECG. There was no difference between the two groups in age, sex, cardiac risk factors, or known CAD. The frequency of ACS for the total study group was 17% (67/387). There was no difference in prevalence of ACS based on the presence or absence of chest pain (16% or 42/261 vs. 20% or 25/126; OR = 0.77, 95% confidence interval = 0.45 to 1.33, p = 0.4). Contrary to our hypothesis concerning patients who presented to the ED with a chief complaint of chest pain, our study demonstrated no difference in the frequency of acute coronary syndrome between patients with chest pain at the time of acquisition of a normal electrocardiogram and those without chest pain during acquisition of a normal electrocardiogram.

Lack of Correlation Between Noninvasive Stress Tests and Invasive Coronary Vasomotor Dysfunction in Patients With Nonobstructive Coronary Artery Disease

Despite a nonobstructive coronary angiogram, many patients may still have an abnormal coronary vasomotor response to provocation and to myocardial demand during stress. The ability of noninvasive stress tests to predict coronary vasomotor dysfunction in patients with nonobstructive coronary artery disease is unknown. All patients with nonobstructive coronary artery disease who had invasive coronary vasomotor assessment and a noninvasive stress test (exercise ECG, stress echocardiography, or stress nuclear imaging) within 6 months of the cardiac catheterization with provocation at our institution were identified (n=376). Coronary vasomotor dysfunction was defined as a percentage increase in coronary blood flow of <or=50% to intracoronary acetylcholine (endothelium-dependent dysfunction) and/or a coronary flow reserve ratio of <or=2.5 to intracoronary adenosine (endothelium-independent dysfunction). We determined the sensitivity and specificity of various noninvasive stress tests to predict coronary vasomotor dysfunction in these patients. On invasive testing, 233 patients (63%) had coronary vasomotor dysfunction, of which 187 patients (51%) had endothelium-dependent dysfunction, 109 patients (29%) had endothelium-independent dysfunction, and 63 patients (17%) had both. On noninvasive stress testing, 157 (42%) had a positive imaging study and 56 (15%) a positive ECG stress test. The noninvasive stress tests had limited diagnostic accuracy for predicting coronary vasomotor dysfunction (41% sensitivity [95% CI, 34 to 47] and 57% specificity [95% CI, 49 to 66]), endothelium-dependent dysfunction (41% sensitivity [95% CI, 34 to 49] and 58% specificity [95% CI, 50 to 65]), or endothelium-independent dysfunction (46% sensitivity [95% CI, 37 to 56] and 61% specificity [95% CI, 54 to 67]). The exercise ECG test was more specific but less sensitive than the imaging tests. This study suggests that a negative noninvasive stress test does not rule out coronary vasomotor dysfunction in symptomatic patients with nonobstructive coronary artery disease. This underscores the need for invasive assessment or novel more sensitive noninvasive imaging for these patients.

Vasculogenic Erectile Dysfunction Is a Predictor of Abnormal Stress Echocardiography

Erectile dysfunction (ED) and atherosclerotic vascular disease have the same risk factors; furthermore, endothelial dysfunction has been shown to be a common link between these conditions. A high prevalence of silent coronary artery disease (CAD) in patients with ED has been observed. The aims of this article were to define the prevalence and identify predictors of occult obstructive CAD in patients with documented vasculogenic ED. Duplex Doppler penile ultrasonography (DUS); exercise stress echocardiography; IIEF; CAD risk factors. Methods. Patients presenting with ED who had penile vascular insufficiency documented by DUS and who had no history of diabetes or symptoms of CAD were prospectively enrolled for noninvasive cardiac stress testing using exercise stress echocardiography. Forty-nine men (mean age 517 years) with an average duration of ED of 2.52 years were evaluated. Penile arterial insufficiency was present in 94%, and venous leak in 20% of patients. Comorbidities included hypertension (51%), hyperlipidemia (41%), and smoking (35%). All patients had at least one vascular risk factor, with 40% having two, 15% three, and 15% four risk factors. Ten patients (20%) had abnormal cardiac stress test. On univariate analysis, age, IIEF-EF domain score, cavernosal artery insufficiency, presence of venous leak, and history of a first-degree relative with CAD were significant predictors. On multivariate analysis, cavernosal artery insufficiency, venous leak, and family history of CAD continued to be predictors of an abnormal stress test. A significant proportion of men with vasculogenic ED have abnormal cardiac stress test. The greatest chance for abnormal cardiac stress test was observed in those with corporo-venocclusive dysfunction or family history of CAD. In some men presenting with ED, even without a CAD history, performing penile DUS or cardiology referral for stress testing should be considered.

Multidetector CT coronary angiography for patient triage to invasive coronary angiography: Performance and cost in ambulatory patients with equivocal or suspected inaccurate noninvasive stress tests

Multidetector-CT angiography (MDCTA) differs from noninvasive stress tests by directly imaging coronary anatomy. The utility of MDCTA for invasive triage is undefined however. We evaluated MDCTA triage to invasive coronary angiography in outpatients with indeterminate or suspected inaccurate stress tests, and estimated cost savings by MDCTA in this role. Consecutive MDCTA patients were retrospectively compared with noninvasive stress tests if performed within 6 months of MDCTA. Twelve-month clinical follow up was obtained for patients not undergoing invasive angiography, and cost using MDCTA for triage to invasive coronary angiography was calculated. MDCTA was performed in 385 patients who had noninvasive stress testing. Stress tests include included treadmill (n = 37), stress echo (n = 178), and nuclear perfusion imaging (n = 170). Invasive angiography was performed in 57 (14.8%). MDCTA compared to CA showed positive and negative predictive values of 94%/100% respectively for lesions found by invasive QCA. Stress testing compared to MDCTA showed positive/negative predictive values of 100%/67% for treadmill exercise, 60%/54% for stress echo, and 59%/55% of nuclear perfusion examinations respectively. One year clinical follow up in 314 patients showed no coronary events in 98% (309) of patients. Triage to invasive angiography by MDCTA showed a 4-fold cost reduction. MDCTA shows excellent performance as a triage for invasive angiography in patients with stress tests that are equivocal or thought inaccurate. A negative CTA confers good 12-month prognosis. Substantial cost savings may accrue using MDCTA in this triage role.

Prise en charge des patients à risque coronaire avant une anesthésie

Noninvasive stress tests such as myocardial perfusion scintigraphy or dobutamine stress echography have to be performed, only if they modify the perioperative strategy. Prophylactic pre-operative coronary revascularization can be helpful only in selected cases, independently from the operative context. Coronary stenting in patients undergoing noncardiac surgery (bare metal stent or drug-eluting stents) adds an additional risk related to antiplatelet therapy management. Preoperative medical therapy optimisation is based on betablockers, and probably statins. Perioperative strategy in risk patients undergoing surgery is multimodal, it includes an adequate preoperative assessment, an optimisation of preoperative medical treatment, an optimisation of the per and post operative myocardial oxygen supply/requirement equilibrium. In case of low risk surgery, or in case of a patient with a good functional capacity, without symptoms, the operative assessment has to be minimal. For patients under antiplatelet therapy, a multidisciplinary discussion of optimal patient management strategy has to be notified in the patient file, this has to include the haemorrhagic and thrombosis discussion.

Abstract 1205: Patients without obstructive coronary artery disease and stress test results: An analysis from the National Cardiovascular Data Registry

Background: In stable patients without known coronary artery disease (CAD), clinical practice guidelines recommend documentation of ischemia prior to evaluation by invasive angiography. We sought to determine how often non-invasive stress testing is performed in this population and the association between stress test results and obstructive CAD. Methods: Patients undergoing cardiac catheterization for exclusion of CAD who were without prior history of myocardial infarction, PCI, or CABG were identified from 601 hospitals using the American College of Cardiology National Cardiovascular Data Registry between 2005 – 2007. Significant obstructive CAD was defined as the presence of any stenosis ≥ 50% left main or ≥ 70% major epicardial vessel. Patient demographics, risk factors, symptoms, stress test status and CAD presence were determined. Results: A total of 376,430 patients without known CAD were identified. The median age was 61 years, 53% were male, 26% had diabetes, and 69% had hypertension. At angiography, 142,912 (38%) of patients were found to have significant obstructive CAD. Symptom status was associated with the presence of CAD (stable angina 50%, atypical 25%, asymptomatic 40%; p&lt;0.001). Stress testing was performed in 316,248 (84%) of patients prior to angiography, and results were associated with the presence of CAD (p&lt;0.001) see Table . Although a positive stress test was noted in 255,617 (68% of patients undergoing cath), obstructive CAD was noted in only 105,435, yielding a positive predictive value of 41%. Conclusions: In a large national registry of stable patients without known CAD undergoing invasive angiography, only 38% were found to have significant obstructive disease. Although performed in 84% of patients prior to cath, the low positive predictive value of current stress tests may have contributed to the high rate of patients without obstructive CAD. Table p value for stress test results and presence of obstructive CAD p&lt;0.001

Impact of fractional flow reserve measurement on the clinical management of patients with coronary artery disease evaluated with noninvasive stress tests prior to cardiac catheterization

Fractional flow reserve (FFR) is often performed to assess the severity of coronary artery stenoses. However, the usefulness of measuring FFR when a noninvasive test has been obtained prior to coronary angiography has not been studied. We retrospectively reviewed 122 patients who underwent noninvasive stress test with cardiac imaging (SPECT or stress echocardiography) prior to FFR assessment of a coronary lesion. The usefulness of FFR measurement was determined. FFR was judged useful if decision to revascularize the patient reflected the result of FFR rather than the result of the stress test. A total of 136 lesions were evaluated. Of these, 66 were associated with a positive noninvasive test and 70 had no ischemia present in the territory of the evaluated vessel. When FFR was negative (> or =0.75) and the test positive (57 lesions), revascularization was deferred in 55. When FFR was positive (<0.75) and the functional test negative (8 lesions), revascularization was performed in 8. FFR measurement changed the clinical decision to revascularize the patient in 55 (83%) of the 66 lesions with ischemia documented on noninvasive tests compared to 8 (11%) of the 70 lesions without ischemia (P<.0001). FFR can be helpful in patients with coronary artery disease even when noninvasive testing is performed prior to coronary angiography. In this study, FFR measurement had the greatest impact in the evaluation of lesions with documented ischemia on noninvasive tests. In these patients, appropriate use of FFR based on the operator's judgment can prevent unnecessary revascularizations of intermediate lesions.

Primary Percutaneous Coronary Intervention With Drug-Eluting Stents

Primary percutaneous coronary intervention (P-PCI) is the preferred reperfusion strategy for patients with ST-segment elevation myocardial infarction if it can be performed rapidly by an experienced team.1 Compared with balloon angioplasty, routine bare-metal stent (BMS) implantation decreases risk for target vessel revascularization (TVR) and possibly reduces myocardial reinfarction rates but does not reduce mortality rates.2,3 Therefore, BMS has become the dominant P-PCI strategy, despite initial concern about increased stent thrombosis rates from delayed healing or inadequate late stent apposition due to initial thrombus trapping. Less established is the role of drug-eluting stents (DES) in P-PCI. DES have the potential to further decrease TVR rates but may increase risk for stent thrombosis. In fact, the risk of stent thrombosis might even be higher in P-PCI than in electively treated patients because of the combination of increased platelet activation, delayed healing, lack of endothelialization, and the proinflammatory and prothrombotic environment in the infarct artery.4 Article see p 103 Several relatively small randomized clinical trials have shown inconsistent efficacy for DES over BMS for P-PCI. Three meta-analyses of these trials have concluded that there is no difference in death or myocardial infarction rates, but TVR rates are decreased.5–7 Variably included were 12 studies that differed in trial design, inclusion criteria, end-point definitions, stent types, duration of clopidogrel treatment, and type of follow-up (angiographic versus clinical). They were limited by sample size and duration of follow-up and usually required angiographic documentation of stent thrombosis, which may have underestimated its true incidence. In this issue of Circulation: Cardiovascular Interventions , Kukreja et al8 report a single-center registry study that is an expanded version of a previous publication.9 Again including the 185 ST-segment elevation myocardial infarction patients treated with Sirolimus-eluting stents (SES) from April 2002 to February 2003, they compare …

Assessing ischemic heart disease in patients with left bundle branch block — An emerging role for multislice computed tomography

Diagnosis of left bundle branch block (LBBB) with concomitant coronary artery disease (CAD) alters the prognosis and the therapeutic management. All common non-invasive stress tests have a limited performance to identify CAD in patients with LBBB. Thus invasive coronary angiography is often needed to confirm or defer obstructive CAD. We propose a new diagnostic algorithm in evaluation of symptomatic and asymptomatic patients with LBBB.

32: Multislice CTA is Effective for Patient Triage to Invasive Coronary Angiography in Ambulatory Patients with Equivocal Noninvasive Stress Tests

32: Multislice CTA is Effective for Patient Triage to Invasive Coronary Angiography in Ambulatory Patients with Equivocal Noninvasive Stress Tests

4.13: Non-invasive stress testing of myocardial perfusion defects: Head-to-head comparison of thallium-201 SPECT to MRI perfusion

This study evaluated the diameters and distensibility of the aortic root as well as the degree of aortic regurgitation (AR) and its effect on left ventricular (LV) function in patients 8.2 ± 3.1 years after they underwent the Ross procedure, with a comparison of these parameters between patients and matched healthy subjects.Eighteen Ross procedure patients (16 male patients, age [mean ± SD] 19.2 ± 3.8 years) and 18 matched healthy subjects (16 male patients, age [mean ± SD] 19.7 ± 4.2 years) underwent magnetic resonance imaging. Measurements for diameters (at 4 levels) and the distensibility of the aortic root were performed using a steady-state free precession sequence. Aortic flow was assessed with a velocity-encoded phase-contrast sequence. Left ventricular systolic function was assessed with a gradient-echo sequence in the short-axis plane. Comparison of parameters was performed using the Mann-Whitney U test. Correlations between diameters, distensibility, AR fraction, and LV systolic function were expressed with Spearman rank correlation coefficients. Linear regression analysis was used to identify predictors of LV systolic dysfunction.Aortic root diameters were increased in Ross procedure patients as compared with healthy subjects (mean difference 6.3-11.6 mm, P ≤ .02 at all 4 levels). Distensibility of the aortic root was lower in patients (1.9 ± 1.1 vs 7.8 ± 3.3 mm Hg−1, P < .01). An AR fraction >5% was present in 14 of the 18 patients (mean AR fraction 8% ± 5% vs 1% ± 1%, P < .01). Left ventricular ejection fraction was lower in patients (50% ± 6% vs 57% ± 6%, P < .01). Dilatation, decreased distensibility, and AR fraction were correlated with impaired LV systolic function (P < .05 for all). The AR fraction predicted impaired LV systolic function (P < .01).Magnetic resonance imaging shows dilatation and decreased distensibility of the aortic root, AR, and consequent impaired LV systolic function in patients after the Ross procedure.

Myocardial Bridging in Absence of Coronary Artery Disease: Proposal of a New Classification Based on Clinical-Angiographic Data and Long-Term Follow-Up

Background: There is no widely accepted classification to guide therapy in patients with symptomatic myocardial bridging (MB). Methods: A retrospective analysis of 157 patients with chest pain, angiographic MB of the left anterior descending artery without obstructive coronary artery disease (CAD) was performed. Patients were evaluated for clinical symptoms, objective signs of ischemia by stress test, intracoronary Doppler flow measurement and coronary flow reserve. 100 patients without CAD or MB served as controls. Results: There was no difference in clinical symptoms and objective signs of ischemia between controls and patients with MB. The length of MB was 22.6 ± 7.8 mm, maximal systolic luminal diameter reduction 71 ± 16%, and maximal mid-diastolic luminal reduction 34.7 ± 13% as demonstrated by quantitative coronary angiography (QCA). Intracoronary Doppler showed significantly increased average peak flow velocity (APV), average systolic peak velocity (ASPV), average diastolic peak flow velocity (ADPV), and maximal peak velocity (MPV) in MB versus proximal and distal segments at rest and after maximal vasodilatation (p < 0.001 for all parameters). Coronary flow reserve was significantly higher proximally (2.9 ± 0.9) compared with segments distal to the MB (2.0 ± 0.6, p < 0.01). We propose a new MB classification for symptomatic patients with MB:Type A:incidental finding on angiography, no objective signs of ischemia; Type B: objective signs of ischemia, and Type C: with or without objective signs of ischemia and altered intracoronary hemodynamics (by QCA/CFR/intracoronary Doppler). 5-Year follow-up data based on this classification showed that types B and C responded well to β-blockers or calcium channel antagonists. Patients with type C refractory to medical therapy were treated with stenting of the MB. Conclusion: Patients with MB without CAD did not have a higher prevalence of chest pain or abnormal non-invasive stress tests compared to patients without CAD or MB. Intracoronary hemodynamic measurement is a novel approach that may be valuable in defining the functional significance of MB. We propose a classification of symptomatic patients with MB without CAD using non-invasive and invasive parameters to guide therapeutic choices.

Role of Coronary Spasm for a Positive Noninvasive Stress Test Result in Angina Pectoris Patients Without Hemodynamically Significant Coronary Artery Disease

A positive noninvasive stress test result is often considered as a false-positive indicator of coronary artery disease (CAD) when coronary angiography reveals no hemodynamically significant CAD. From January 2001 through December 2004, 5474 patients scheduled to undergo exercise electrocardiogram (ECG) [exercise ECG without imaging or exercise ECG with thallium-201 (201Tl) single photon emission tomography (SPECT)] or dipyridamole 201Tl tomography at our outpatient clinic because of chest oppressive sensation were included in this prospective study. Coronary angiography was performed when a noninvasive test result was positive for ischemia or when ischemic chest pain was suspected. Intracoronary methylergonovine testing was performed when spastic angina was suspected and coronary angiography showed no hemodynamically significant CAD. Noninvasive stress testing was positive in 113 (67%) patients with coronary spasm. Of the 53 patients who had positive exercise ECG (exercise ECG with or without imaging), ST depression was found in 50 patients and ST elevationin in 3 patients. Multivessel spasm was found in 6 (15%), 6 (15%), and 7 (21%) of the patients with a positive result on exercise ECG without imaging, exercise ECG with 201Tl SPECT, and dipyridamole 201Tl SPECT, respectively. There was no significant difference in the results of noninvasive stress testing and the number of vessels with coronary spasm (1-vessel spasm versus multivessel spasm) among these 3 noninvasive stress testing groups. Intracoronary ergonovine testing induced coronary spasm in over 50% of patients who had suspected ischemic chest pain, a positive noninvasive stress test, and no hemodynamically significant CAD.