Dipyridamole Stress Test Research Articles

Safety of new contrast agent, Sonazoid, for contrast-enhanced myocardial perfusion echocardiography during dipyridamole stress test

Safety of new contrast agent, Sonazoid, for contrast-enhanced myocardial perfusion echocardiography during dipyridamole stress test

Diagnostic accuracy of myocardial perfusion by sonazoid-enhanced ultraharmonic imaging during dipyridamole stress test

Diagnostic accuracy of myocardial perfusion by sonazoid-enhanced ultraharmonic imaging during dipyridamole stress test

Evaluation of wall motion abnormality by comparing values of cardiac output obtained by M-mode and Doppler echocardiography: Parameter revealing wall motion abnormality in stress echocardiography.

Dobutamine and dipyridamole stress echocardiographies are both well able to detect myocardial ischemia resulting from coronary diseases by recognizing the regional wall motion abnormality (WMA). Here we report a method for describing WMA in detail. In pharmacological stress echocardiography, because of difficulties in recognizing the two-dimensional pattern, accuracy sometimes depends upon the skill of the operator. Two stroke volumes obtained using the M-mode and Doppler methods were examined to detect abnormal regional cardiac function by the dipyridamole stress test. Stroke volume obtained by the M-modereflects regional cardiac function and that estimated from the outflow using the Doppler methodreflects total cardiac function. These two stroke volumes were compared in normal subjects and patients with coronary-diseases. The results indicated consistent discrepancies between these two stroke volume in the ischemic hearts as a results of coronary stenosis, whereas changes in stroke volumes in the normal subjects showed the same tendency. This method of combining information about the regional and total functions is thus useful in examining the WMA and regional cardiac function, although it can not be applied to subjects whose stroke volume does not increase under stress.

Effects of acute myocardial ischemia on QT dispersion by Dipyridamole stress echocardiography

Increased dispersion of the QT interval has been observed during pacing or exercise stress testing in patients with coronary artery disease (CAD). It has not been established whether this phenomenon is a consequence of ischemia. Therefore, we sought to evaluate whether dipyridamole-induced myocardial ischemia, as directly detected by echocardiographic monitoring of regional contractile function, would affect QT dispersion. Twenty-four patients with nonsignificant and 34 patients with significant CAD but no previous myocardial infarction underwent dipyridamole stress echocardiography while not taking medications. QT dispersion was measured on a 12-lead electrocardiogram at baseline and at various times after dipyridamole infusion. Dipyridamole infusion did not influence QT dispersion in patients without CAD. QT dispersion was similarly unaffected in patients with CAD in whom dipyridamole did not induce wall motion abnormalities. In contrast, in patients with positive dipyridamole stress test findings, QT dispersion increased from 60 ± 17 ms at baseline to 94 ± 25 ms during peak infusion (p <0.0001), with a time course mirroring that of development of contractile abnormalities. QT dispersion returned to 63 ± 25 ms upon relief of ischemia by administration of aminophylline. The increase in QT dispersion was significantly related to the extent of contractile dysfunction induced by dipyridamole. Although ST-segment depression occurred in only 40% of patients with positive dipyridamole stress test findings, 88% of such patients had an increase in QT dispersion. Analysis of the receiver-operating characteristic curve showed that a QT dispersion increase of ≥20 ms identified positive findings for dipyridamole stress echocardiography with 68% sensitivity and 91% specificity. Thus, QT dispersion is acutely affected by myocardial ischemia induced by the administration of dipyridamole. Measurement of QT dispersion may improve detection of stress-induced ischemia on surface electrocardiograms.

Myocardial Contrast Echocardiography Yields Best Accuracy Using Quantitative Analysis of Digital Data from Pulse Inversion Technique: Comparison with Second Harmonic Imaging and Harmonic Power Doppler During Simultaneous Dipyridamole Stress SPECT Studies

This prospective study assesses the (1) feasibility of quantifying ultrasound myocardial perfusion studies based on the densitometric analysis of digital data and the (2) comparison of pulse inversion, second harmonic and harmonic power Doppler modalities with SPECT. Twenty-three patients with suspected ischaemic heart disease had i.v. injections of Tc-Sestamibi and Optison during a dipyridamole stress test for echocardiography in pulse inversion, second harmonic and harmonic power Doppler mode. Analysis was (a) visual by scoring and (b) quantitative by densitometry of digital data for background subtracted myocardial opacification (a.u.) and normalized contrast effect (%). In the nine control patients, myocardial opacification at stress was greater (P< or =0.002) than in the pathologic group (5. +/- 3.3 vs 2.6 +/- 2.5 a.u. in pulse inversion, 5.4 +/- 2.1 vs 2.4 +/- 1.8 in second harmonic and 7.1 +/- 3.7 vs 4.9 +/- 3.7 a.u. in harmonic power Doppler). In the pathologic group, normalized contrast effect decreased significantly during stress (23.7 +/- 18.8 to 11.3 +/- 10.8%, P<0.003) only in pulse inversion. Kappa values for patient based diagnostic agreement with SPECT were 0.75 by pulse inversion, 0.62 by second harmonic and 0.52 by harmonic power Doppler for quantitative analysis, and 0.51, 0.37 and 0.35 respectively, for visual assessment. Myocardial contrast echocardiography should be analysed using densitometry of digital data. The new technique pulse inversion demonstrates best agreement with SPECT data.

Myocardial Contrast Echocardiography Yields Best Accuracy Using Quantitative Analysis of Digital Data from Pulse Inversion Technique: Comparison with Second Harmonic Imaging and Harmonic Power Doppler During Simultaneous Dipyridamole Stress SPECT Studies

Aims: This prospective study assesses the (1) feasibility of quantifying ultrasound myocardial perfusion studies based on the densitometric analysis of digital data and the (2) comparison of pulse inversion, second harmonic and harmonic power Doppler modalities with SPECT. Methods and Results: Twenty-three patients with suspected ischaemic heart disease had i.v. injections of Tc-Sestamibi and Optison ® during a dipyridamole stress test for echocardiography in pulse inversion, second harmonic and harmonic power Doppler mode. Analysis was (a) visual by scoring and (b) quantitative by densitometry of digital data for background subtracted myocardial opacification (a.u.) and normalized contrast effect (%). In the nine control patients, myocardial opacification at stress was greater ( P ≤0·002) than in the pathologic group (5·8±3·3 vs 2·6±2·5 a.u. in pulse inversion, 5·4±2·1 vs 2·4±1·8 in second harmonic and 7·1±3·7 vs 4·9±3·7 a.u. in harmonic power Doppler). In the pathologic group, normalized contrast effect decreased significantly during stress (23·7±18·8 to 11·3±10·8%, P <0·003) only in pulse inversion. Kappa values for patient based diagnostic agreement with SPECT were 0·75 by pulse inversion, 0·62 by second harmonic and 0·52 by harmonic power Doppler for quantitative analysis, and 0·51, 0·37 and 0·35 respectively, for visual assessment. Conclusion: Myocardial contrast echocardiography should be analysed using densitometry of digital data. The new technique pulse inversion demonstrates best agreement with SPECT data. Copyright 2002 The European Society of Cardiology. Published by Elsevier Science Ltd. All rights reserved .

Left Ventricular Systolic Dysfunction in Patients with Obstructive Sleep Apnea Syndrome

Conflicting results have been reported regarding the effects of obstructive sleep apnea syndrome (OSAS) on daytime left ventricular (LV) systolic function. This study aimed to assess the prevalence and causes of LV systolic dysfunction, using radionuclide angiography, in a large group of patients with OSAS. A prospective study in the pneumology department of a university medical center. One hundred sixty-nine consecutive patients with OSAS diagnosed by polysomnography, hospitalized for the administration of nasal continuous positive airway pressure. Patients with a known cardiac disease were excluded. LV ejection fraction (LVEF) was measured in all patients, using radionuclide ventriculography with multiple-gated equilibrium cardiac imaging. Myocardial scintigraphy with a dipyridamole stress test and echocardiography were performed in those patients with LV systolic dysfunction, defined by a LVEF < 50%, to detect silent heart disease, especially coronary artery disease. LV systolic dysfunction was observed in 7.7% (13 of 169 patients). In these 13 patients, the mean +/- SD LVEF was 42 +/- 6%, the lowest value of LVEF was 32%, and no silent cardiac disease was revealed. Age, body mass index, apnea-hypopnea index, parameters of nocturnal oxyhemoglobin desaturation, and prevalence of systemic hypertension did not significantly differ between patients with LVEF < 50% and those with LVEF > 50%. In seven patients with LV dysfunction, LVEF was measured following treatment of OSAS and reached normal values. OSAS may be a direct cause of daytime LV systolic dysfunction that can resolve following reversal of nocturnal apneas.

Ischemic ECG response during dipyridamole stress testing is a powerful predictor of severe coronary artery disease in patients with claudication due to peripheral arterial disease

Ischemic ECG response during dipyridamole stress testing is a powerful predictor of severe coronary artery disease in patients with claudication due to peripheral arterial disease

QTc interval shortening during dipyridamole stress test predicts severe coronary artery disease in patients with left bundle-branch block

QTc interval shortening during dipyridamole stress test predicts severe coronary artery disease in patients with left bundle-branch block

Dipyridamole Myocardial Perfusion Tomography in Patients with Severe Aortic Stenosis

Patients with aortic stenosis (AS) may have classic angina pectoris. The safety of exercise testing in adults with AS is controversial and, in fact, exercise testing in such patients is considered to be contraindicated especially in severe aortic stenosis (SAS). Furthermore, exercise testing has low specificity in uncovering coronary artery disease (CAD) in patients with AS, because the baseline ECG is frequently abnormal. We wished to assess the safety and diagnostic accuracy of dipyridamole stress myocardial perfusion tomography (DMPT) in the detection of CAD in patients with SAS. Methods: The study included 30 patients with SAS (mean aortic valve area 0.57 ± 0.09 cm²). All patients underwent dipyridamole myocardial perfusion scintigraphy (SPECT), coronary arteriography and catheterization, as well as Doppler echocardiography. Myocardial perfusion tomography was applied with ^99mTc hexakis-2-methoxyisobutyl isonitrile (MIBI) by a single day rest-dipyridamole infusion protocol. Hemodynamic, electrocardiographic and clinical responses were compared with those of 50 control patients without AS. Results: Hemodynamic responses during dipyridamole stress tests demonstrated no significant differences between the controls and the AS patients in the following parameters: systolic blood pressure, heart rate, rate-pressure product or incidence of headache, chest pain, dyspnea, flushing and dizziness. A reversible perfusion defect was observed in 10 patients with DMPT. The existence of coronary lesions was determined by coronary arteriography in 8 of 10 patients (sensitivity 100%, specificity 91%). Conclusion: The results showed that DMPT is well tolerated, even by patients with SAS and is of high diagnostic value in assessing CAD.

Sign of wall motion abnormality observed in wall thickness change, excursion, and stroke volume obtained by M-mode: The parameter revealing wall motion abnormality in stress echocardiography (2)

To improve the evaluation of regional wall motion abnormalities (WMA) during stress echocardiography, the parameters of the wall thickness change, excursion and stroke volume, with time-dependent changes in two regional portions of the interventricular septum and the posterior wall evaluated with M-mode ultrasonography are proposed. Response to the dipyridamole stress test was studied in two normal subjects and eight subjects with coronary disease. Regional wall motion and stroke volume were measured, and the results were compared with results obtained with coronary angiography, 2-D echography, and radioisotope scintigraphy. In normal subjects, these parameters showed only monotonous change with the passage of time. In patients with coronary artery disease, however, discrepancy in wall thickness and excursion between the interventricular septum and the posterior wall appeared within 1 to 3 minutes after the start of the test. Thus, despite the limitation of the examined area imposed by use of M-mode, the motion of the interventricular septum and the posterior wall described the details of WMA and an ischemic state.

Tc-99m sestamibi gated SPECT in patients with left bundle branch block.

The purpose of this study was to assess the diagnostic role of a Tc-99m sestamibi gated SPECT technique in patients with left bundle branch block (LBBB) without known coronary artery disease. Twenty consecutive patients with constant complete LBBB were included. A same-day rest-stress protocol was used, and dipyridamole stress (14 patients) or treadmill exercise (6 patients) was applied. Electrocardiograph (ECG)-gated SPECT images were acquired 15 minutes after the administration of 0.31 mCi/kg Tc-99m sestamibi at peak stress. Regional myocardial perfusion was analyzed in relation to the cardiac cycle. Eleven of 14 patients who underwent a dipyridamole stress test had hypoactivity in the left anterior descending (LAD) artery territory in the ungated (summed) stress-rest images (abnormality ratio, 78%). On the ungated images, the abnormality was completely reversible in one patient (9%), partially reversible in five patients (46%), irreversible in two patients (18%), and reverse perfusion was identified in three patients (27%). Abnormality ratios of end-systolic and end-diastolic data were 93% and 29%, respectively. Conversely, the ungated rest-stress and end-systolic images of all the patients who performed treadmill exercise were abnormal despite the presence of normal or nearly normal end-diastolic myocardial perfusion. The angiographic findings correlated best with those of end-diastolic images. In 13 patients without coronary artery disease, normal or nearly normal regional perfusion was observed on end-diastole, but four patients with abnormal end-diastolic perfusion, which involved the LAD territory in all but one, had substantial coronary artery disease. The number of the involved segments was similar on the end-systolic and ungated data. Most of these artifactual defects were localized to the anteroseptal, septal, and inferoseptal segments. These preliminary data indicate that end-diastolic images can significantly reduce artifactual defects in patients with LBBB. The resolution of an LBBB pattern on end-diastolic data would significantly improve the diagnostic role of myocardial perfusion studies in these patients.

Incidence of major cardiovascular events in black patients with normal myocardial stress perfusion study results

Background. Previous studies have shown that the risk of major cardiovascular events at 1 year is less than 1% in patients with normal myocardial stress perfusion study results. However, the racial distribution of patients enrolled in these studies is not known. Hence, the prognostic value of normal stress perfusion study results in black patients is not well established. Our objective was to determine the incidence of major cardiovascular events in black patients with normal stress perfusion study results over a 12-month period. Methods and Results. We searched the nuclear cardiology database at our institution for all black patients who had normal stress perfusion study results between January 1990 and December 1996. We excluded patients with a history of coronary revascularization, valvular heart disease, cardiomyopathy, congenital heart disease, left bundle branch block, or pre-excitation syndrome. Patients were followed up for at least 12 months from the time of inclusion. A total of 592 patients were enrolled and were followed up for 18 ± 6 months (mean ± SD). Of these, 388 underwent treadmill exercise testing, 155 underwent dipyridamole stress testing, and the remainder underwent dobutamine stress testing. Perfusion studies were performed in all patients with thallium 201 single photon emission computed tomography imaging. During the follow-up period, 11 cardiac deaths and 7 myocardial infarctions (MIs) occurred. The incidence of cardiac deaths was 1.2% per year, and that of nonfatal MIs was 0.8% per year. The total incidence of major cardiovascular events was 2% per year. In patients who underwent treadmill exercise testing, the incidence of major cardiovascular events was 1% per year. Performance of a pharmacologic stress test and a prior MI were significantly associated with death or nonfatal MI (P < .05). Conclusions. The overall incidence of major cardiovascular events in black patients after normal exercise perfusion study results were obtained was low (1%). However, black patients who had normal perfusion study results but underwent pharmacologic stress testing or had a history of MI were at intermediate risk. These patients require close surveillance for major cardiovascular events. (J Nucl Cardiol 2001;8:541-7.)

Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis.

To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter). In each study, dobutamine (5 to 40 microg kg(-1) min(-1) in 3-min stages) and pacing (20 bpm increments, each 2 min, up to 260 bpm) were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min). The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05) reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery). Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1) the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2) in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 +/- 11%) and dipyridamole (-18 +/- 16%) tests as compared to dobutamine (-9 +/- 6%) (P = 0.05), but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery) (pacing: -16 +/- 7%; dipyridamole: -25 +/- 16%; dobutamine: -26 +/- 10%; not significant), and 3) a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery stenosis. The pacing stress test was less sensitive, but the difference was not statistically significant. The magnitude of segmental left ventricular dysfunction induced by ischemia was similar in all stress tests evaluated.

Safety, feasibility, and diagnostic accuracy of accelerated high-dose dipyridamole stress echocardiography

Protocols for dipyridamole stress testing have evolved in the last 16 years in the neverending quest of optimal diagnostic accuracy and user friendliness. Higher dipyridamole dose in a shorter infusion time provides higher sensitivity, but concern over safety is still controversial. An accelerated high-dose (0.84 mg/kg in 6 minutes without atropine) dipyridamole stress test was performed on 1,295 patients in 2 echocardiographic laboratories: Institute of Clinical Physiology of Pisa and Niguarda Hospital of Milan. During testing, there were no deaths and no patients had ventricular fibrillation. Major adverse reactions occurred in 3 cases (1 every 431 studies): 1 myocardial infarction, 1 brief cardiac asystole, and 1 transient ischemic attack. Overall feasibility was 97%. In 66 patients with normal function at rest who were evaluated off therapy, with coronary angiography performed independently of test results, the accelerated high-dose protocol showed a sensitivity of 85% (confidence interval [CI] 73% to 92%) and a specificity of 93% (CI 83% to 97%) for angiographically assessed coronary artery disease (quantitatively assessed diameter reduction ≥50%). Diagnostic accuracy of the accelerated high dose was 89% (CI 79% to 95%). Thus, accelerated high-dose dipyridamole stress echocardiography was reasonably safe and well tolerated. This protocol is especially appealing for its excellent diagnostic accuracy coupled with the short imaging time and no need for drug cocktails.

7.45 Relationship between changes in systolic blood pressure during dipyridamole stress test and ischaemic myocardial perfusion SPECT patterns

7.45 Relationship between changes in systolic blood pressure during dipyridamole stress test and ischaemic myocardial perfusion SPECT patterns

12.6 Demonstration of myocardial stunning after dipyridamole stress test with gated perfusion SPECT

12.6 Demonstration of myocardial stunning after dipyridamole stress test with gated perfusion SPECT

341 Clinical significance of an unconventional marker of transmural ischaemia — The QTc interval shortening in Q wave leads during Dipyridamole stress testing — Early after myocardial infarction

341 Clinical significance of an unconventional marker of transmural ischaemia — The QTc interval shortening in Q wave leads during Dipyridamole stress testing — Early after myocardial infarction

328 Value of a simple ECG parameter — The QTc interval shortening during dipyridamole stress testing — In predicting severe coronary artery disease in patients with left bundle branch block

328 Value of a simple ECG parameter — The QTc interval shortening during dipyridamole stress testing — In predicting severe coronary artery disease in patients with left bundle branch block

Comparing a high-dose dipyridamole SPECT imaging protocol with dobutamine and exercise stress testing protocols. Part III: Using dobutamine to determine lung-to-heart ratios, left ventricular dysfunction, and a potential viability marker

Determination of the severity of coronary artery disease (CAD) by single photon emission computed tomography (SPECT) imaging has previously been shown to have greater sensitivity, specificity, and accuracy when performed with pharmacologic stress using dobutamine than by standard dose dipyridamole (SDD) or exercise stress testing (EST) prior to SPECT imaging. The use of lung to heart (L:H) ratios has been shown to be valuable in determining the presence or absence of left main (LM) or triple vessel (3V) CAD. No such work has been previously reported for dobutamine. Twenty-one patients were studied using dobutamine (n = 7) or EST (n = 14). These results were compared with results from Part II of this series of studies using high-dose dipyridamole (HDD) pharmacologic stress. In this study, patients underwent L:H ratio analysis following injection of 3 mCi of Tl-201, this provides sufficient time for thallium clearance from the blood pool. Results of the L:H ratios were compared with the results of coronary arteriographic (CA) evaluation. Patients who were “stressed” via EST demonstrated statistically greater (p ≤ 0.001) L:H ratios in patients with LM/3V CAD when compared with patients who had 0–2 significantly stenosed coronary arteries. Patients stressed with dobutamine demonstrated lower L:H ratios (p=NS) in patients with LM/3V CAD than was seen for patients with 0–2 V CAD. Patients stressed with dobutamine had statistically (p ≤ 0.05) lower L:H ratios than did similar patients stressed with EST. Increased L:H ratios following EST and HDD, as shown previously in Part II of this series, provide excellent markers for LM/3V CAD following Tl-201 injection. The presence of “normal” L:H ratios in patients with LM/3V CAD following dobutamine stress may suggest the presence of “stunned” or “hibernating” myocardium. The presence of “decreased” L:H ratios following dobutamine after HDD or EST has already shown an increased L:H ratio, might suggest a marker for myocardial viability that deserves further investigation.