Eugenio Picano

Stress echocardiography and the human factor: The importance of being expert

The aim of this study was to evaluate how the diagnostic accuracy of a stress echocardiographic procedure, such as a dipyridamole echocardiography test, depends on the specific experience of the physician interpreting the test. Recordings of 50 consecutive dipyridamole echocardiographic tests were selected for the first part of the study. They were analyzed by 20 experienced echocardiographers with different backgrounds in stress echocardiography: 10 beginners (less than 20 stress studies interpreted with trained staff) and 10 experienced observers (greater than or equal to 100 stress studies performed). Diagnostic accuracy (true positive + true negative/total number of tests) versus the angiographic reference standard (greater than 70% coronary stenosis of at least one major coronary artery) was 62 +/- 6% for beginners and 85 +/- 3% for experienced observers (p less than 0.0001). In the second part of the study, 10 observers (5 beginners and 5 experienced observers) evaluated 2 different sets of 50 dipyridamole echocardiographic test studies before and after the training of the beginners. Before training, the accuracy of beginners was lower than that of experienced observers (61 +/- 7% versus 85 +/- 3%; p less than 0.001). After training, the accuracy gap was closed (83 +/- 3% versus 86 +/- 2%; p = NS). Therefore, interpretation of stress echocardiographic tests by an echocardiographer without specific training severely underestimates the diagnostic potential of this technique. One hundred stress echocardiographic studies are more than adequate to build the individual learning curve and reach the plateau of diagnostic accuracy that the test can yield.

Safety and tolerability of dobutamine-atropine stress echocardiography: a prospective, multicentre study

Abstract Summary Diagnostic tests that are hazardous or infeasible, or both, may become accepted before inadequacies are recognised; only multicentre trials can provide the necessary information for an unrestricted acceptance of any new diagnostic procedure. We prospectively studied the results obtained in 24 experienced echocardiography laboratories. 2949 tests were done in 2799 patients. In 341 tests (12% of the overall population, 21% of the negative tests) the test could not be completed because of complex ventricular tachyarrhythmias (134, 38% of all submaximal studies); nausea and/or headache (71, 20%); hypotension and/or bradycardia (62, 17%); supraventricular tachyarrhythmias (44, 12%); hypertension (24, 7%); and others (20, 6%). Dangerous events (life-threatening complications or side-effects requiring specific treatment and lasting more than 3 hours, or new hospital admission) occurred in 14 cases (1 every 210 tests)—9 cardiac (3 ventricular tachycardias; 2 ventricular fibrillations; 2 myocardial infarctions; 1 prolonged antidote-resistant myocardial ischaemia; 1 severe, persistent hypotension) and 5 extracardiac (atropine poisoning with hallucinations lasting several hours in the absence of either myocardial ischaemia or hypotension). Life-threatening and/or longlasting complications may occur during dobutamine/atropine stress echocardiography. The test is generally well tolerated, although may be interrupted by minor, self-limiting, usually symptomless side-effects.

High dose dipyridamole echocardiography test in effort angina pectoris

The dipyridamole echocardiography test (intravenous dipyridamole with two-dimensional echocardiographic monitoring) was performed in 93 patients with effort chest pain and in 10 control subjects. The test was considered positive when regional asynergy appeared after dipyridamole administration. When negative at the low dose (0.56 mg/kg body weight in 4 minutes), the test was repeated on a different day with a higher dose (0.84 mg/kg in 10 minutes). All 93 patients underwent coronary arteriography; 72 of them had significant (greater than 70% luminal reduction) coronary artery disease. Thirty-eight of the 93 patients had a positive low dose dipyridamole echocardiography test; 15 other patients with a negative low dose test had a positive high dose test. All 53 patients with a positive test had significant coronary artery disease; 12 of them had a negative exercise stress test. In relation to the presence of coronary artery disease, the dipyridamole echocardiography test had an overall specificity higher than that of the exercise stress test (100 versus 71%) and a similar overall sensitivity (74 versus 69%). The dipyridamole echocardiography test is feasible in all patients with a good baseline echocardiogram. It detects the site of apparent ischemia more precisely than does an exercise stress test, and can unmask electrocardiographically silent ischemia. If performed in patients with a negative low dose dipyridamole echocardiography test, the high dose test adds sensitivity (probably by achieving maximal dilation in patients in whom the low dose is only partially effective), without any loss in specificity and with no apparent increase in risk.

Value of rest thallium-201/technetium-99m sestamibi scans and dobutamine echocardiography for detecting myocardial viability

The relation between radioisotopic and echocardiographic markers of myocardial viability and postrevascularization recovery of function is still to be defined. To this purpose, 14 patients (11 men, 3 women, aged 35 to 64 years, mean 54 +/- 7) with ventricular dysfunction were studied by a multiparametric approach. Each patient underwent, on separate days, rest thallium-201 and technetium-99m sestamibi scintigraphy, dobutamine echocardiography and coronary angiography. Coronary angiography was analyzed by a quantitative approach. Thallium uptake at rest was quantified from planar early (10-minute) and delayed (16-hour) thallium-201 images and expressed as a percentage of maximal activity in each projection using a 13-segment model. Sestamibi uptake was expressed in the same way. Dobutamine (up to 10 micrograms/kg/min) echocardiography was analyzed using a score index ranging from 1 (normokinesia) to 4 (dyskinesia) and a similar segmental model. Before revascularization 50 segments were grouped as normal (coronary stenosis < 50% and normal function, group 1); of the remaining 132 segments with > 50% coronary stenosis, 57 had normal wall motion (group 2) and 75 showed regional dyssynergies (group 3). Early and delayed thallium-201 regional percent activities did not differ in group 1 and in group 2 but were significantly less in group 3 segments. Sestamibi percent activity was more in group 1 and significantly reduced both in group 2 and 3 segments. Segments with improved wall motion after dobutamine had more early, delayed thallium-201 and sestamibi percent activities than unresponsive segments. Postrevascularization echocardiography was performed in all patients. Delayed thallium-201 scans and dobutamine echocardiography showed good sensitivity and specificity in detecting viable myocardium. (ABSTRACT TRUNCATED AT 250 WORDS)

Cancer risk from professional exposure in staff working in cardiac catheterization laboratory: Insights from the National Research Council's Biological Effects of Ionizing Radiation VII Report

BACKGROUND Occupational doses from fluoroscopy-guided interventional procedures are the highest ones registered among medical staff using x-rays. The aim of the present study was to evaluate the order of magnitude of cancer risk caused by professional radiation exposure in modern invasive cardiology practice. METHODS From the dosimetric Tuscany Health Physics data bank of 2006, we selected dosimetric data of the 26 (7 women, 19 men; age 46 +/- 9 years) workers of the cardiovascular catheterization laboratory with effective dose >2 mSv. Effective dose (E) was expressed in milliSievert, calculated from personal dose equivalent registered by the thermoluminescent dosimeter, at waist or chest, under the apron, according to the recommendations of National Council of Radiation Protection. Lifetime attributable risk of cancer was estimated using the approach of Biological Effects of Ionizing Radiation 2006 report VII. RESULTS Cardiac catheterization laboratory staff represented 67% of the 6 workers with yearly exposure >6 mSv. Of the 26 workers with 2006 exposure >2 mSv, 15 of them had complete records of at least 10 (up to 25) consecutive years. For these 15 subjects having a more complete lifetime dosimetric history, the median individual effective dose was 46 mSv (interquartile range = 24-64). The median risk of (fatal and nonfatal) cancer (Biological Effects of Ionizing Radiation 2006) was 1 in 192 (interquartile range = 1 in 137-1 in 370). CONCLUSIONS Cumulative professional radiological exposure is associated with a non-negligible Lifetime attributable risk of cancer for the most exposed contemporary cardiac catheterization laboratory staff.

Prognostic value of dobutamine-atropine stress echocardiography early after acute myocardial infarction

OBJECTIVES The aim of this multicenter, multinational, prospective, observational study was to assess the relative value of myocardial viability and induced ischemia early after uncomplicated myocardial infarction. BACKGROUND Dobutamine-atropine stress echocardiography allows evaluation of rest function (at baseline), myocardial viability (at low dose) and residual ischemia (peak dose, up to 40 micrograms with atropine up to 1 mg) in one test. METHODS Dobutamine-atropine stress echocardiography was performed 12 +/- 5 days (mean +/- SD) after a first uncomplicated acute myocardial infarction in 778 patients (677 men; mean age 58 +/- 10 years) with technically satisfactory rest echocardiographic study results. Patients were followed-up for 9 +/- 7 months. RESULTS Dobutamine-atropine stress echocardiographic findings were positive for myocardial ischemia in 436 of patients (56%) and negative in 342 (44%). During follow-up, there were 14 cardiac-related deaths (1.8% of the total cohort), 24 (2.9%) nonfatal myocardial infarctions and 63 (8%) hospital readmissions for unstable angina. One hundred seventy-four patients (22%) underwent coronary revascularization (bypass surgery or coronary angioplasty). Spontaneous events occurred in 61 of 436 patients with positive and 40 of 342 patients with negative findings on dobutamine-atropine stress echocardiography (14% vs. 12%, p = 0.3). When only spontaneously occurring events were considered, the most important predictor was myocardial viability (chi-square 9.7). Using the Cox proportional hazards model, only the presence of myocardial viability (hazard ratio [HR] 2.0, p < 0.002) and age (HR 1.03, p < 0.001) were predictive of spontaneously occurring events. When only hard cardiac events were considered, age was the strongest predictor (chi-square 3.6, p = 0.056), followed by wall motion score index (WMSI) at peak dose (chi-square 3.3, p = 0.06) and remote ischemia (chi-square 2.25, p = 0.1). When cardiac death was considered, WMSI at peak dose was the best predictor (HR 9.2, p < 0.0001). CONCLUSIONS During dobutamine stress, echocardiographic recognition of myocardial viability is more prognostically important than echocardiographic recognition of myocardial ischemia for predicting unstable angina, whereas WMSI at peak stress was the best predictor of cardiac-related death. Different events can be recognized with different efficiency by various stress echocardiographic variables.

Prognostic value of dipyridamole echocardiography early after uncomplicated myocardial infarction: A large-scale, multicenter trial

PURPOSE To determine the prognostic capability of the dipyridamole echocardiography test (DET) early after an acute myocardial infarction. PATIENTS AND METHODS On the basis of 11 different echocardiographic laboratories, all with established experience in stress echocardiography and fulfilling quality-control requirements for stress echocardiographic readings, 925 patients were evaluated after a mean of 10 days from an acute myocardial infarction and followed up for a mean of 14 months. RESULTS During the follow-up, there were 34 deaths and 37 nonfatal myocardial infarctions; 104 patients developed class III or IV angina and 149 had coronary revascularization procedures (bypass or angioplasty). Considering all spontaneous events (angina, reinfarction, and death), the most important univariate predictor was the presence of an inducible wall motion abnormality after dipyridamole administration (chi 2 = 45.8). With a Cox analysis, echocardiographic positivity, age, and male gender were found to have an independent and additive value. Considering survival (and, therefore, death as the only event), age was the most meaningful parameter, followed by the wall motion score index during dipyridamole administration (chi 2 = 12.1). Among other parameters, the resting wall motion score index was a significant predictor of death. In a multivariate analysis, the prognostic contributions of age (relative risk estimate = 1.08) and wall motion score index during dipyridamole administration (relative risk estimate = 4.1) were independent and additive. In particular, considering death only, the event rate was 2% in patients with negative DET results, 4% in patients with positive high-dose DET results, and 7% in patients with positive low-dose DET results. CONCLUSIONS DET is feasible and safe early after uncomplicated myocardial infarction and allows effective risk stratification on the basis of the presence, severity, extent, and timing of the induced dyssynergy.

Prognostic Value of Myocardial Viability in Medically Treated Patients With Global Left Ventricular Dysfunction Early After an Acute Uncomplicated Myocardial Infarction A Dobutamine Stress Echocardiographic Study

BACKGROUND Residual viable myocardium identified by dobutamine stress after myocardial infarction may act as an unstable substrate for further events such as subsequent angina and reinfarction. However, in patients with severe global left ventricular dysfunction, viability might be protective rather than detrimental. The aim of this study was to assess the impact on survival of echocardiographically detected viability in medically treated patients with global left ventricular dysfunction evaluated after acute uncomplicated myocardial infarction. METHODS AND RESULTS The data bank of the large-scale, prospective, multicenter, observational Echo Dobutamine International Cooperative (EDIC) study was interrogated to select 314 medically treated patients (271 men; age, 58+/-9 years) who underwent low-dose (</=10 microg x kg-1 x min-1) dobutamine for the detection of myocardial viability and high-dose dobutamine for the detection of myocardial ischemia (</=40 microg x kg-1 x min-1 with atropine </=1 mg) performed 12+/-6 days after an acute uncomplicated myocardial infarction and showing a moderate to severe resting left ventricular dysfunction (wall motion score index [WMSI] >1.6). Patients were followed up for 9+/-7 months. Low-dose dobutamine stress echocardiography identified myocardial viability in 130 patients (52%). Dobutamine-atropine stress echocardiography was positive for ischemia in 148 patients (47%) and negative in 166 patients (53%). During the follow-up, there were 12 cardiac deaths (3.8% of the total population). With the use of Cox proportional hazards model, delta low-dose WMSI (the variation between rest WMSI and low-dose WMSI) was shown to exert a protective effect by reducing cardiac death by 0.8 for each decrease in WMSI at low-dose dobutamine (coefficient, -0.2; hazard ratio, 0.8; P<0.03); WMSI at peak stress was the best predictor of cardiac death in this set of patients (hazard ratio, 14.9; P<0.0018). CONCLUSIONS In medically treated patients with severe global left ventricular dysfunction early after acute uncomplicated myocardial infarction, the presence of myocardial viability identified as inotropic reserve after low-dose dobutamine is associated with a higher probability of survival. The higher the number of segments showing improvement of function, the better the impact is of myocardial viability on survival. The presence of inducible ischemia in this set of patients is the best predictor of cardiac death.

Dipyridamole-echocardiography test in effort angina pectoris.

This study assesses the clinical feasibility and usefulness of dipyridamole infusion for the detection of coronary artery disease (CAD) by using 2-dimensional echocardiography (2-D echo) and 12-lead electrocardiographic monitoring. Dipyridamole infusion (0.14 mg/kg/min for 4 minutes) was performed in 66 consecutive patients with effort chest pain and in 9 control subjects. Among the 28 patients with positive dipyridamole-echocardiography test responses, 18 had diagnostic electrocardiographic changes (ST-segment depression on anterolateral leads), but these changes were unrelated to the site of asynergy. The dipyridamole-echocardiography test had an overall sensitivity of 56% and specificity of 100% for the presence of CAD. Exercise stress testing (EST) had an overall sensitivity of 62% and a specificity of 80%. Thus, the dipyridamole-echocardiography test, which is feasible in essentially all patients with good basal echocardiograms, has a lower overall sensitivity in detecting CAD than EST but a higher specificity, detects the site of apparent ischemia as identified by regional asynergy more precisely than EST, and can unmask electrocardiographically silent effort ischemia.

The Emerging Role of Exercise Testing and Stress Echocardiography in Valvular Heart Disease

Exercise testing has an established role in the evaluation of patients with valvular heart disease and can aid clinical decision making. Because symptoms may develop slowly and indolently in chronic valve diseases and are often not recognized by patients and their physicians, the symptomatic, blood pressure, and electrocardiographic responses to exercise can help identify patients who would benefit from early valve repair or replacement. In addition, stress echocardiography has emerged as an important component of stress testing in patients with valvular heart disease, with relevant established and potential applications. Stress echocardiography has the advantages of its wide availability, low cost, and versatility for the assessment of disease severity. The versatile applications of stress echocardiography can be tailored to the individual patient with aortic or mitral valve disease, both before and after valve replacement or repair. Hence, exercise-induced changes in valve hemodynamics, ventricular function, and pulmonary artery pressure, together with exercise capacity and symptomatic responses to exercise, provide the clinician with diagnostic and prognostic information that can contribute to subsequent clinical decisions. Nevertheless, there is a lack of convincing evidence that the results of stress echocardiography lead to clinical decisions that result in better outcomes, and therefore large-scale prospective randomized studies focusing on patient outcomes are needed in the future.