Safety, feasibility, and prognostic implications of pharmacologic stress echocardiography in 1482 patients evaluated in an ambulatory setting

Nourin-Dependent miR-137 and miR-106b: Novel Biomarkers for Early Diagnosis of Myocardial Ischemia in Coronary Artery Disease Patients

Background: Although cardiovascular imaging techniques are widely used to diagnose myocardial ischemia in patients with suspected stable coronary artery disease (CAD), they have limitations related to lack of specificity, sensitivity and “late” diagnosis. Additionally, the absence of a simple laboratory test that can detect myocardial ischemia in CAD patients, has led to many patients being first diagnosed at the time of the development of myocardial infarction. Nourin is an early blood-based biomarker rapidly released within five minutes by “reversible” ischemic myocardium before progressing to necrosis. Recently, we demonstrated that the Nourin-dependent miR-137 (marker of cell damage) and miR-106b-5p (marker of inflammation) can diagnose myocardial ischemia in patients with unstable angina (UA) and also stratify severity of ischemia, with higher expression in acute ST-segment elevation myocardial infarction (STEMI) patients compared to UA patients. Minimal baseline-gene expression levels of Nourin miRNAs were detected in healthy subjects. Objectives: To determine: (1) whether Nourin miRNAs are elevated in chest pain patients with myocardial ischemia suspected of CAD, who also underwent dobutamine stress echocardiography (DSE) or ECG/Treadmill stress test, and (2) whether the elevated levels of serum Nourin miRNAs correlate with results of ECHO/ECG stress test in diagnosing CAD patients. Methods: Serum gene expression levels of miR-137, miR-106b-5p and their corresponding molecular pathway network were measured blindly in 70 enrolled subjects using quantitative real time PCR (qPCR). Blood samples were collected from: (1) patients with chest pain suspected of myocardial ischemia (n = 38) both immediately “pre-stress test” and “post-stress test” 30 min. after test termination; (2) patients with acute STEMI (n = 16) functioned as our positive control; and (3) healthy volunteers (n = 16) who, also, exercised on ECG/Treadmill stress test for Nourin baseline-gene expression levels. Results: (1) strong correlation was observed between Nourin miRNAs serum expression levels and results obtained from ECHO/ECG stress test in diagnosing myocardial ischemia in CAD patients; (2) positive “post-stress test” patients with CAD diagnosis showed upregulation of miR-137 by 572-fold and miR-106b-5p by 122-fold, when compared to negative “post-stress test” patients (p < 0.001); (3) similarly, positive “pre-stress test” CAD patients showed upregulation of miR-137 by 1198-fold and miR-106b-5p by 114-fold, when compared to negative “pre-stress test” patients (p < 0.001); and (4) healthy subjects had minimal baseline-gene expressions of Nourin miRNAs. Conclusions: Nourin-dependent miR-137 and miR-106b-5p are promising novel blood-based biomarkers for early diagnosis of myocardial ischemia in chest pain patients suspected of CAD in outpatient clinics. Early identification of CAD patients, while patients are in the stable state before progressing to infarction, is key to providing crucial diagnostic steps and therapy to limit adverse cardiac events, improve patients’ health outcome and save lives.

Is 3D Dobutamine stress echocardiography ready for prime time? Diagnostic and prognostic implications

Aims

Compare the diagnostic accuracy and prognostic value of echo contrast enhanced 2D and 3D Dobutamine stress echocardiography (DSE).

Methods and results

We included 718 patients indicated for DSE. All had standard 2D, and contrast enhanced left ventricular opacification (LVO) for 2D and 3D acquisitions at rest and peak stress. Chi-square test was done to assess relationship between DSE result and early revascularization. Kaplan–Meier plots with Logistic regression analysis predicted late major adverse cardiovascular events (MACE) at a maximum follow-up of 84 months. The mean age was 63 ± 13 years (61% males) and follow-up was obtained in 692/718 (96.4%) patients. Only 32% had excellent baseline image quality. The DSE was abnormal in 19.4% patients on 2D, in 17.1% on 2D-LVO and in 19.1% on 3D-LVO. Early revascularization was performed in, respectively, 32.8%, 45.8%, and in 48.5% of stress-positive 2D, 2D-LVO, and 3D-LVO studies. After excluding the 66 patients receiving early revascularization 68/626 (10.9%) had MACE at a maximum follow-up of 84 months. Kaplan–Meier plots showed that stress-positive 2D-LVO and 3D-LVO studies not receiving early revascularization when assessed separately and combined had significantly worse outcomes for MACE compared with stress-negative patients (OR 3.69; 95% CI: 1.54–8.87; P = 0.011, OR 4.54; 95% CI: 1.72–12.93; P = 0.008, and OR 7.07, 95% CI: 1.62–25.16; P = 0.001, respectively).

Conclusion

Combined use of 2D- and 3D-LVO DSE is ready for prime time considering the feasibility, improved diagnostic accuracy and prognostic value.

Occurrence of Atrial Fibrillation During Dobutamine Stress Echocardiography

Dobutamine stress echocardiography (DSE) is a widely used examination for assessment of coronary ischemia, but several complications have been reported. The aim of this study was to assess the incidence of atrial fibrillation (AF) during DSE, and a systematic review and meta-analysis were also performed to determine an accurate estimate of the AF incidence. Over a 16-year period, we reviewed all patients referred for DSE. We systematically analyzed all ECG performed during DSE to detect AF during the examination. DSE was completely performed in 4,818 patients (mean age: 62.1 ± 11.7 years). AF was observed in 40 patients (31 men, mean age: 79.7 ± 8.9 years). Incidence of AF during DSE was 0.83%. Regarding the meta-analysis, the combined AF incidence was 0.86%. In our study, patients with AF occurrence had more frequent previous history of paroxysmal AF (p = 0.02) were also older (p < 0.0001) and incidence of AF during DSE increased with age: 0% below 60 years, 0.45% in patients 60 to 69 years, 1.3% in patients 70 to 79 years, and 4% in patients >80 years (p < 0.0001). In multivariate analysis, the factors significantly associated with an increased risk of AF were age (adjusted odds ratio (aOR) = 2.4, 95% confidence interval: 1.5 to 3.3, p = 0.003) and previous history of paroxysmal AF (aOR = 1.5, 95% confidence interval: 1.1 to 1.9; p = 0.04). In conclusion, AF is uncommon during DSE, and elderly patients and patients with previous history of paroxysmal AF are at risk of AF during DSE.

Cardiac Magnetic Resonance in Stable Coronary Artery Disease: Added Prognostic Value to Conventional Risk Profiling

Aims

Cardiovascular magnetic resonance (CMR) permits a comprehensive evaluation of stable coronary artery disease (CAD). We sought to assess whether, in a large contemporaneous population receiving optimal medical therapy, CMR independently predicts prognosis beyond conventional cardiovascular risk factors (RF).

Methods

We performed a single centre, observational prospective study that enrolled 465 CAD patients (80% males; 63±11 years), optimally treated with ACE-inhibitors/ARB, aspirin, and statins (76-85%). Assessments included conventional evaluation (clinical history, atherosclerosis RF, electrocardiography, and echocardiography) and a comprehensive CMR with LV dimensions/function, late gadolinium enhancement (LGE), and stress perfusion CMR (SPCMR).

Results

During a median follow-up of 62 months (IQR 23-74) there were 50 deaths and 92 major adverse cardiovascular events (MACE). CMR variables improved multivariate model prediction power of mortality and MACE over traditional RF alone (F-test p<0.05 and p<0.001, respectively). LGE was an independent prognostic factor of mortality (hazard ratio [95% CI]: 3.4 [1.3−8.8]); moreover, LGE (3.3 [1.7−6.3]) and SPCMR (2.1 [1.4−3.2]) were the best predictors of MACE.

Conclusion

LGE is an independent noninvasive marker of mortality in the long term in patients with stable CAD and optimized medical therapy. Furthermore, LGE and SPCMR independently predict MACE beyond conventional risk stratification.

Assessment of Myocardial Ischemia in Obese Individuals Undergoing Physical Stress Echocardiography (PSE)

BACKGROUND

Physical stress echocardiography is an established methodology for diagnosis and risk stratification of coronary artery disease in patients with physical capacity. In obese (body mass index ≥ 30 kg/m2) the usefulness of pharmacological stress echocardiography has been demonstrated; however, has not been reported the use of physical stress echocardiography in this growing population group.

OBJECTIVE

To assess the frequency of myocardial ischemia in obese and non-obese patients undergoing physical stress echocardiography and compare their clinical and echocardiographic differences.

METHODS

4,050 patients who underwent treadmill physical stress echocardiography were studied according to the Bruce protocol, divided into two groups: obese (n = 945; 23.3%) and non-obese (n = 3,105; 76.6%).

RESULTS

There was no difference regarding gender. Obese patients were younger (55.4 ± 10.9 vs. 57.56 ± 11.67) and had a higher frequency of hypertension (75.2% vs. 57, 2%; p < 0.0001), diabetis mellitus (15.2% vs. 10.9%; p < 0.0001), dyslipidemia (59.5% vs 51.9%; p < 0.0001), family history of coronary artery disease (59.3% vs. 55.1%; p = 0.023) and physical inactivity (71.4% vs. 52.9%, p < 0.0001). The obese had greater aortic dimensions (3.27 vs. 3.14 cm; p < 0.0001), left atrium (3.97 vs. 3.72 cm; p < 0.0001) and the relative thickness of the ventricule (33.7 vs. 32.8 cm; p < 0.0001). Regarding the presence of myocardial ischemia, there was no difference between groups (19% vs. 17.9%; p = 0.41). In adjusted logistic regression, the presence of myocardial ischemia remained independently associated with age, female gender, diabetes and hypertension.

CONCLUSION

Obesity did not behave as a predictor of the presence of ischemia and the physical stress echocardiography. The application of this assessment tool in large scale sample demonstrates the feasibility of the methodology, also in obese.

Safety and feasibility of dobutamine stress cardiac magnetic resonance for cardiovascular assessment prior to renal transplantation

AIMS

Current guidelines recommend cardiovascular risk assessment prior to renal transplantation. There is currently no evidence for the role of cardiovascular magnetic resonance (CMR) in this population, despite an established evidence base in the non-chronic kidney disease (CKD) population. Our aim is to determine the feasibility and safety of dobutamine stress CMR (DSCMR) imaging in the risk stratification of CKD patients awaiting renal transplantation.

METHODS

CKD patients who were deemed at high risk for coronary artery disease (CAD) and awaiting renal transplantation underwent DSCMR.

RESULTS

Forty-one patients whose median age was 56 years (range 28–73 years) underwent DSCMR. Nineteen were undergoing haemodialysis, 10 peritoneal dialysis and 12 pre-dialysis. The aetiology of the renal failure was diabetes mellitus in 29%, glomerulonephritis in 24%, hypertension in 22% and autosomal dominant polycystic kidney disease in 10%. Thirty-eight patients (93%) achieved the end point, either positive for ischaemia or negative, achieving at least 85% of age-predicted heart rate. Two of them did not achieve target heart rate and one was discontinued because of severe headache. Of the 38 patients who achieved the end point, 35 (92%) were negative for inducible wall motion abnormalities and four (10%) were positive. There were no serious adverse effects.

CONCLUSION

DSCMR is a well tolerated and viable investigation for the cardiovascular risk stratification of high-risk CKD patients prior to renal transplantation. DSCMR already has an established evidence base in the non-CKD population with superiority over other noninvasive techniques. Larger studies with outcome data are now required to define its true utility in the CKD population.

Association of cystatin C with ischemia in patients with coronary heart disease

BACKGROUND

Elevated concentrations of cystatin C are associated with greater cardiovascular morbidity and mortality. We sought to determine whether elevated concentrations of cystatin C were associated with inducible ischemia in patients with coronary heart disease (CHD).

METHODS

We measured serum cystatin C and performed exercise treadmill testing with stress echocardiography in a cross-sectional study of 899 outpatients with CHD.

RESULTS

Among the 241 participants in the highest quartile of cystatin C (>1.30 mg/L), 38% had inducible ischemia, compared with 13% of those in the lowest quartile of cystatin C < 0.92 mg/L; adjusted odds ratio [OR]: 2.1; 95% confidence interval [CI]: 1.2 to 3.8; p = 0.01). However, this association differed in participants with and without a history of coronary artery bypass graft (CABG), as well as in users and nonusers of beta-blockers and statins (p values for interaction < 0.1). Among participants without a history of CABG, 35% of those in the highest quartile and 9% of those in the lowest quartile of cystatin C had inducible ischemia (adjusted OR: 3.05; 95% CI: 1.3-6.9; p = 0.008). Among participants who were not using beta-blockers, 44% of those in the highest quartile and 7% in the lowest quartile of cystatin C had inducible ischemia (adjusted OR: 5.3; 95% CI: 1.8-15.5; p = 0.002). Among participants who were not using statins, 39% of participants in the highest quartile and 4% of those in the lowest quartile had inducible ischemia (adjusted OR: 10.3; 95% CI: 2.5-43.3; p = 0.001).

CONCLUSIONS

Elevated levels of cystatin C are independently associated with inducible ischemia among outpatients with stable coronary disease.

Safety of contrast administration for endocardial enhancement during stress echocardiography compared with noncontrast stress

The aim was to evaluate the safety of stress echocardiography using contrast (CE) for endocardial enhancement compared with a noncontrast (NCE) cohort in a large nonselect population. The recent Food and Drug Administration warning cited lack of data for safety regarding the use of contrast in conjunction with stress echocardiography. A detailed record review was performed for 5,069 consecutive patients who underwent stress echocardiography (58% pharmacologic, 42% exercise) during an 8-year period. Contrast use, hemodynamics, and adverse clinical and electrocardiographic events were evaluated until time of discharge from the laboratory. Contrast was administered to 2,914 patients (58%) and was higher in in-patients (66%) and during dobutamine stress (67%). Compared with the NCE group, the CE group was older (median age 61 vs 58 years) and had more depressed left ventricular ejection fraction <50% (14% vs 11%; all p <0.001). The CE group experienced more chest pain (11% vs 8%; p = 0.001), back pain (0.6% vs 0.05%; p <0.001), and premature ventricular contractions (odds ratio 1.42, 95% confidence interval 1.19 to 1.69, p <0.001). There was no sustained ventricular tachycardia, ventricular fibrillation, cardiac arrest, or death in either group. One uncomplicated acute myocardial infarction and 1 anaphylactoid reaction occurred in the CE group, and none occurred in the NCE group (p = 0.51). Rates of clinically significant arrhythmias were similar in both groups (CE 2.1% vs NCE 1.9%; p = 0.8). In conclusion, although CE of echocardiographic images was used more often in patients with a higher cardiac risk profile, the risk of major adverse events was very small in both the CE and NCE stress echocardiography cohorts.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Feasibility, safety and tolerability of accelerated dobutamine stress echocardiography

A continuous infusion of a single high dose of dobutamine has been, recently, suggested as a simple and effective protocol of stress echocardiography. The present study assesses the feasibility, safety, and tolerability of an accelerated dobutamine stress protocol performed in patients with suspected or known coronary artery disease. Two hundred sixty five consecutive patients underwent accelerated dobutamine stress echocardiography: the dobutamine was administered at a constant dose of 50 μg/kg/min for up to 10 minutes. The mean weight-adjusted cumulative dose of dobutamine used was 330 ± 105.24 μg/kg. Total duration of dobutamine infusion was 6.6 ± 2.1 min. Heart rate rose from 69.9 ± 12.1 to 123.1 ± 22.1 beats/min at peak with a concomitant change in systolic blood pressure (127.6 ± 18.1 vs. 167.6 ± 45.0 mmHg). Dobutamine administration produced a rapid increase in heart rate (9.4 ± 5.9 beats/min²). The side effects were similar to those described with the standard protocol; the most common were frequent premature ventricular complexes (21.5%), frequent premature atrial complexes (1.5%) and non sustained ventricular tachycardia (1.5%); among non cardiac symptoms the most frequent were nausea (3.4%), headache (1.1%) and symptomatic hypotension (1.1%). No major side effects were observed during the test. Our data demonstrate that a continous infusion of a single high dose of dobutamine is a safe and well tolerated method of performing stress echocardiography in patients with suspected or known coronary artery disease. This new protocol requires the administration of lower cumulative dobutamine dose than standard protocol and results in a significant reduction in test time.

[Acute myocardial infarction with cardiogenic shock following stress echocardiography: case report]

Acute myocardial infarction is a rare complication of dobutamine stress echocardiography (DSE). We report the case of a 60-year-old man with moderate apical sequela of a myocardial infarction (MI) which had an inferior MI complicated with cardiogenic shock and circulatory arrest two hours after a positive DSE in that very circulatory topography. Emergency coronarography objectivizes a dissection of the circumflex artery. The patient required a circulatory assistance device. He survived the episode and left the hospital with 50% left ventricular ejection fraction.

Short-term Risk Stratification with Accelerated High-dose Dipyridamole Stress Echocardiography: Follow-up into 301 Consecutive Outpatients

AIM

This study aimed to assess the short-term predictive value of a pharmacologic stress echocardiography test performed with accelerated high-dose dipyridamole (0.84 mg/kg over 6 minutes).

METHODS

In all, 301 patients (161 men, mean age 61.41 +/- 11.62 years) were scheduled for accelerated high-dose dipyridamole stress test. A total of 22 tests were interrupted prematurely because of side effects (overall feasibility 92.7%). The patients were followed up for nonfatal myocardial infarction, unstable angina, myocardial revascularization, and sudden death at first and third months and each 6 months (maximum 18 months).

RESULTS

A positive echocardiographic response was found in 25 patients. Six patients with negative stress test experienced events. Eight patients with positive stress test went to coronary revascularization procedure. Negative predictive value was 97.8%, positive predictive value was 32%, sensitivity was 57%, and specificity was 94%.

CONCLUSIONS

Risk stratification with accelerated high-dose dipyridamole stress echocardiography is effective. A negative test predicts favorable short-term cardiovascular prognosis.

Dynamic left ventricular outflow tract obstruction induced by dobutamine stress echocardiography leading to myocardial ischemia and infarction

Left ventricular outflow tract (LVOT) obstruction occurring during dobutamine stress echocardiography (DSE) occurs in approximately 15-20% of patients undergoing DSE. The clinical significance and mechanism of LVOT obstruction has been debated, but is now generally felt to result from the pharmacological effects of dobutamine in increasing inotropy and causing peripheral vasodilation. It must be realized that in rare instances, ischemia may occur and lead to wall motion abnormalities and eventually myocardial infarction. We present the case of a 70-year-old asymptomatic woman who underwent a routine pre-operative cardiac stress evaluation and was found to develop a dynamic outflow tract obstruction leading to myocardial ischemia and infarction.

Cardiac stress MR imaging with dobutamine

Stress testing for detection of ischemia-induced wall-motion abnormalities has become a mainstay for noninvasive diagnosis and risk stratification of patients with suspected coronary artery disease (CAD). Recent technical developments in magnetic resonance imaging (MRI), including the adoption of balanced steady-state free precession (b-SSFP) sequences-preferentially in combination with parallel imaging techniques-have led to a significant reduction of imaging time and improved patient safety. The stress protocol includes application of high-dose dobutamine (up to 40 microg/kg/min) combined with fractionated atropine (up to a maximal dose of 1.0 mg). High-dose dobutamine stress MRI revealed good sensitivity (83-96%) and specificity (80-100%) for detection of significant CAD. Myocardial tagging methods have been shown to further increase sensitivity for CAD detection. Severe complications (sustained tachycardia, ventricular fibrillation, myocardial infarction, cardiogenic shock) are rare but may be expected in 0.1-0.3% of patients. Dobutamine stress MRI has emerged as a reliable and safe clinical alternative for noninvasive assessment of CAD. New pulse sequences, such as real-time imaging, might obviate the need for breath holding and electrocardiogram (ECG) triggering in patients with severe dyspnoea and cardiac arrhythmias, which may further improve the clinical impact and acceptance of stress MRI in the future.

Dobutamine cardiovascular magnetic resonance: A review

Dobutamine cardiovascular magnetic resonance (DCMR) is useful for identifying myocardial ischemia and viability in patients with known or suspected coronary artery disease (CAD). This article reviews the performance and utility of DCMR, its association with dobutamine stress echocardiography (DSE), and areas of active investigative research.

Comparison of safety and efficacy of the early injection of atropine during dobutamine stress echocardiography with the conventional protocol

Although dobutamine-atropine stress echocardiography (DASE) is an established method for evaluating patients who have coronary artery disease (CAD), it can increase test duration and a patient's exposure to large doses of dobutamine. New protocols, including the early injection of atropine during dobutamine stress echocardiography (EA-DSE), have been proposed to decrease test duration. This study compared the safety, efficacy, and accuracy of EA-DSE with those of DASE. We retrospectively evaluated 3,163 patients who underwent DASE and 1,664 patients who underwent EA-DSE over a period of 12 years. In EA-DSE, atropine at a dose </=2 mg was started with 20 microg/kg/min of dobutamine if heart rate was <100 beats/min. Diagnostic accuracy for detecting CAD (>50% stenosis) was assessed in patients who underwent quantitative angiography </=3 months of stress testing. The dobutamine dose used in EA-DSE was smaller than that used in DASE (31 +/- 6 vs 36 +/- 6 microg/kg/min, p <0.0001), although the atropine dose was larger (0.8 +/- 0.5 vs 0.5 +/- 0.25 mg, p <0.0001). EA-DSE resulted in a significantly shorter duration of dobutamine infusion (12.4 +/- 2.0 vs 14.6 +/- 2.5 minutes, p <0.0001), more diagnostic studies (88% vs 81%, p <0.0001), and a lower incidence of minor adverse effects than did DASE. The rate of major adverse effects was similar in the 2 protocols. Sensitivities, specificities, positive predictive values, negative predictive values, and accuracies for detecting CAD were 84%, 90%, 93%, 76%, and 86% for EA-DSE and 86%, 78%, 84%, 79%, and 82% for DASE, respectively (p = NS). Therefore, EA-DSE is a safe and effective alternative to DASE and had a similar accuracy for the detection of CAD.

Association between renal insufficiency and inducible ischemia in patients with coronary artery disease: the heart and soul study

Chronic renal insufficiency (CRI) is a predictor of stroke, cardiovascular, and all-cause mortality, but the mechanisms responsible for these associations are unclear. Whether CRI was associated with severity of coronary artery disease (CAD) as measured by exercise stress echocardiography among outpatients with stable CAD was evaluated. This study is a cross-sectional analysis of the Heart and Soul study, a prospective cohort of patients with known CAD. Renal function was assessed by 24-h urine collection, and CRI was defined as measured creatinine clearance < or =60 ml/min. Exercise stress echocardiography was used to identify inducible ischemia, defined as any wall motion abnormality seen at stress but not at rest. Logistic regression was used to evaluate the association of CRI with exercise-induced ischemia after adjustment for cardiovascular risk factors. Participants with CRI composed 97 (23%) of the 431 participants and were characterized by older age, worse CAD, lower ejection fraction, greater left ventricular mass and higher C-reactive protein values. The prevalence of exercise-induced ischemia was also substantially greater in the participants with CRI (42% versus 23%; odds ratio [OR], 2.3; 95% confidence interval [CI], 1.4 to 3.8; P < 0.001). This association was minimally changed by adjustment for traditional cardiovascular risk factors and coronary disease history (OR, 2.0; 95% CI, 1.3 to 3.3; P < 0.01) and remained strong even after adjustment for C-reactive protein (OR, 2.3; 95% CI, 1.0 to 5.1; P = 0.04). CRI is strongly associated with exercise-induced ischemia in patients with CAD. The greater severity of atherosclerotic disease observed in patients with CRI may in part explain the association of CRI with increased cardiovascular risk among individuals with CAD.

Non-invasive detection of coronary artery disease by dobutamine-stress echocardiography in children after heart transplantation

BACKGROUND

Coronary vasculopathy is the main cause of cardiac graft failure. Because yearly coronary angiography is invasive in children, a non-invasive method for detecting graft vasculopathy is needed. The aim of this study was to test dobutamine-stress echocardiography in a pediatric population to determine its feasibility, safety and reliability in the detection of graft coronary artery disease.

METHODS

Eighteen patients, aged 2 days to 16.8 years at transplantation (mean 8.4 years), underwent 44 dobutamine-stress echocardiography (DSE) exams, at a follow-up of 1.1 to 11.8 years (mean 5.1 years). Selective coronary angiography was performed for comparison. Echocardiographic recordings were obtained in 4 standard views of the left ventricle and measurements carried out within the frames of a 16-segment model. Segmental scores of contractility were obtained for each segment and a total segmental contractility index was calculated at each stage.

RESULTS

All patients reached the maximum dose stage. Maximum heart rate was 57% to 90% of predicted maximum. Maximum systolic blood pressure reached 190 mmHg. Segmental scores were normal in 37 and abnormal in 7 cases. Echographic results were concordant with angiography in 82% and discordant in 18% of the cases (4 negative DSEs with minor angiographic lesions, 2 positive DSEs with normal angiography), but there was no significant angiographic lesion with normal DSE.

CONCLUSIONS

DSE is a safe and highly feasible non-invasive technique in transplanted children. A normal DSE study successfully predicts the absence of significant coronary artery disease in the post-transplant population.

Stress echo results predict mortality: a large-scale multicenter prospective international study

OBJECTIVES

The purpose of this study was to assess the long-term value of pharmacologic stress echocardiography with either dipyridamole or dobutamine (DET) for prediction of cardiac death in patients with proven or suspected coronary artery disease (CAD).

BACKGROUND

Stress echocardiography is an established, cost-effective technique for the detection of CAD.

METHODS

From the Echo Persantine International Cooperative-Echo Dobutamine International Cooperative data bank, 7,333 patients (5,452 males; 59 +/- 10 years) underwent pharmacologic stress echocardiography with either high-dose dipyridamole (0.84 mg/kg over 10 min) (n = 4,984) or high-dose dobutamine (up to 40 microg/kg/3 min) (n = 2,349) for diagnostic purposes. Patients were followed up for a mean of 2.6 years (range 1 to 206 months).

RESULTS

The DET was positive for myocardial ischemia in 2,854 (35%) patients and negative in 4,479 (61%) patients. During the follow-up there were 161 cardiac deaths (sudden death and fatal myocardial infarction) (2.1% of the total population). Kaplan-Meier survival estimates showed a significantly better outcome for those patients with a negative pharmacologic stress echocardiography test compared with those with a positive test (92 vs. 71.2%, p = 0.0000).

CONCLUSIONS

Pharmacologic stress echocardiography with either dipyridamole or dobutamine is effective in predicting cardiac death during a long-term follow-up. A negative stress echocardiography test result is related to a favorable outcome.

Use of pharmaceuticals in noninvasive cardiovascular diagnosis

A number of pharmaceuticals are employed as diagnostic agents for cardiovascular diseases. Four groups of agents are reviewed here: 1) vasoactive substances employed as adjuncts to physical maneuvers in diagnosis of structural heart disease; 2) vasodilators used to produce heterogeneity of coronary flow; 3) sympathomimetic agents simulating the effects of exercise on the heart for the purpose of detection of coronary artery stenosis; and 4) ultrasonic contrast agents used to enhance myocardial imaging for the assessment of segmental wall motion. In the first group are amyl nitrate, a vasodilator, and methoxamine and phenylephrine, both vasopressors. The vasodilators of the second group are dipyridamole and adenosine. When combined with scintigraphic perfusion imaging or with echocardiographic assessment of segmental wall motion, these agents can detect single- or multiple-vessel coronary artery disease with sensitivity and specificity comparable to submaximal exercise. They are especially useful for preoperative risk assessment before noncardiac surgery. The sympathomimetic agents of the third group, dobutamine and arbutamine, increase myocardial contractility and heart rate, and dilate the peripheral vasculature. As with the vasodilators, when combined with nuclear or echocardiographic techniques they are equivalent to exercise in detection of coronary disease. They are especially useful in patients with bronchospastic disease and for assessment of myocardial viability. Agents from groups 2 and 3 have acceptable side-effect and safety profiles. The last group reviewed includes echocardiographic contrast agents that, in this investigative setting, are employed to enhance detection of segmental wall motion when used with agents from groups 2 and 3.