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PubMed1996

Dobutamine positron emission tomography: absolute quantitation of rest and dobutamine myocardial blood flow and correlation with cardiac work and percent diameter stenosis in patients with and without coronary artery disease.

OBJECTIVES: This study sought to measure myocardial blood flow at rest and during dobutamine infusion and to correlate flow with cardiac work and severity of coronary artery disease. BACKGROUND: Dobutamine is used with cardiac imaging to induce possible ischemia in patients with known or suspected coronary artery disease. Positron emission tomography permits noninvasive quantitation of myocardial blood flow. METHODS: Fifteen patients with quantitative coronary arteriography were studied at rest and during dobutamine infusion using nitrogen-13 ammonia flow imaging with positron emission tomography. Myocardial blood flow was determined in regions corresponding to the three major coronary arteries for myocardium with and without dobutamine flow defects and with and without a > 50% diameter stenosis. RESULTS: Eight patients had at least one dobutamine flow defect; four of whom had a previous myocardial infarction. One patient with > 50% diameter stenosis had no flow defects, and one with < 50% diameter stenosis (48%) had one defect. Dobutamine significantly increased myocardial blood flow in regions with and without a dobutamine flow defect or > 50% diameter stenosis, with a greater increase when a defect or > 50% diameter stenosis was not present. Rest and dobutamine flows in regions without > 50% diameter stenosis were 0.93 +/- 0.20 (mean +/- SD) and 2.16 +/- 0.52 ml/min per g (p < 0.01), respectively. The corresponding flows in regions without a defect were 0.94 +/- 0.21 and 2.17 +/- 0.53 ml/min per g (p < 0.01), respectively. This 2, 4-fold increase in flow was significantly correlated (p < 0.001) with a 2.2-fold increase in rate-pressure product induced by dobutamine. The rest and dobutamine flows for regions subtended by a vessel with > 50% diameter stenosis were 0.70 +/- 0.33 and 1.20 +/- 0.54 ml/min per g (p < 0.05), respectively, whereas the corresponding values for regions with a dobutamine flow defect were 0.69 +/- 0.33 ml/min per g at rest and 1.23 +/- 0.54 ml/min per g during dobutamine (p < 0.05). Dobutamine increased flow inversely proportional to percent diameter stenosis. The rest flow for regions with a dobutamine flow defect were not significantly different from that in regions without defects. CONCLUSIONS: Dobutamine resulted in a significant increase in myocardial blood flow that correlated significantly with both increased cardiac work and degree of stenosis.

Adult↗

PubMed1997

Dobutamine pharmacokinetics during dobutamine stress echocardiography.

Many patients fail to achieve target heart rate during dobutamine stress echocardiography (DSE). We evaluated the pharmacokinetics of dobutamine during DSE to determine whether patients with an impaired chronotropic response have higher rates of dobutamine clearance and consequently relatively lower plasma dobutamine levels. Plasma dobutamine levels, heart rate, and left ventricular (LV) ejection fraction (EF) were measured in 13 male patients referred for DSE at baseline and at the end of stepped 3-minute dobutamine infusions of 5, 10, 20, and 30 microg/kg/min. Dobutamine levels increased with doses: 27 +/- 10, 111 +/- 17, 275 +/- 17, and 403 +/- 28 ng/ml (mean +/- SEM). There was no relation observed between the plasma dobutamine level achieved at the 30-microg infusion dose and the increase in heart rate from baseline (r = 0.066; p = 0.83). Baseline LVEF and a measure of chronotropic beta responsivity were identified as independent predictors of dobutamine clearance, together accounting for 73% of the variance in dobutamine clearance. In conclusion, (1) there is a dose-dependent increase in plasma dobutamine levels during DSE, (2) dobutamine clearance is positively related to baseline LVEF and is partially mediated by a beta-receptor mechanism, and (3) an impaired chronotropic response during DSE is not due to failure to achieve a sufficiently high dobutamine level. We conclude that in patients who lack an adequate heart rate response during the early stages of DSE (e.g., up to 20 microg/kg/min infusion), administration of atropine rather than progressively higher amounts of dobutamine may provide a more effective strategy to achieve target heart rate.

Adrenergic beta-Agonists↗

PubMed1987

Interaction of dopamine, (+/-)-dobutamine and the (-)-enantiomer of dobutamine with alpha- and beta-adrenoceptors in the pulmonary circulation of the dog.

The effects of dopamine, (+/-)-dobutamine (racemic mixture) and (-)-dobutamine on alpha-adrenoceptor-mediated vasoconstriction were evaluated in the pulmonary circulation of the anesthetized dog. The drugs were studied in the absence and presence of propranolol (1 mg/kg, i.v.) in order to assess beta-adrenoceptor-mediated effects in the pulmonary circulation. Intra-arterial administration of dopamine, (+/-)-dobutamine and (-)-dobutamine elicited dose-dependent increases in pulmonary perfusion pressure, reflecting increases in pulmonary vascular resistance. In control animals, dopamine elicited the largest increases in pulmonary perfusion pressure (45% above resting pulmonary pressure) followed by (-)-dobutamine (30% increase) and (+/-)-dobutamine (15% increase). The pressor effects of dopamine in the pulmonary circulation were mediated by both postjunctional vascular alpha 1- and alpha 2-adrenoceptors, since prazosin, (100 micrograms/kg, i.v.), a selective alpha 1-adrenoceptor antagonist, and rauwolscine (100 micrograms/kg, i.v.), a selective alpha 2-adrenoceptor antagonist, both inhibited the vasopressor response elicited by dopamine to roughly equivalent degrees. Pulmonary vasoconstriction produced by (+/-)-dobutamine and (-)-dobutamine was mediated primarily by postsynaptic vascular alpha 1-adrenoceptors, although alpha 2-adrenoceptor-mediated vasoconstriction was observed. In propranolol-pretreated animals, the increase in pulmonary perfusion pressure elicited by dopamine and (-)-dobutamine was qualitatively and quantitatively similar to that observed in control animals, suggesting that these agents have little activity on vascular beta 2-adrenoceptors in the pulmonary circulation. In marked contrast, the maximum pulmonary vasopressor response obtained with (+/-)-dobutamine were greater in propranolol-pretreated animals, indicating that (+/-)-dobutamine also has the capacity to stimulate pulmonary vascular beta 2-adrenoceptors which mediate pulmonary vasodilation that, in part, mask alpha-adrenoceptor-mediated pulmonary vasoconstriction. Since the (-)-enantiomer of dobutamine has little or no beta 2-adrenoceptor agonist activity, the beta 2-adrenoceptor-mediated effect of (+/-)-dobutamine must result from the (+)-enantiomer as has been previously proposed. The results of the present study indicate that dopamine has a greater propensity for increasing pulmonary vascular resistance, and therefore pulmonary arterial blood pressure, relative to (+/-)-dobutamine. This results, at least in part, from the relatively weaker activity of dopamine in stimulating pulmonary vascular beta 2-adrenoceptors which mediate vasodilation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1997

Cardiac risk assessment before vascular surgery: a prospective study comparing clinical evaluation, dobutamine stress echocardiography, and dobutamine Tc-99m sestamibi tomoscintigraphy.

Preoperative evaluation for cardiac risk assessment before peripheral vascular surgery remains controversial. Between January and June 1994, a prospective open study was carried out in 156 patients scheduled for elective vascular procedures (63 carotid endarterectomies, 34 abdominal aortic aneurysms, 29 aortoiliac and 30 infrainguinal reconstructions) to compare the ability of clinical data, dobutamine stress echocardiography, and dobutamine Tc-99m sestamibi tomoscintigraphy to predict postoperative cardiac events. Pharmacological stress testing consisted of incremental dobutamine infusion (+/-1 mg atropine to achieve 85% of age-predicted maximal heart rate, with continuous echocardiographic monitoring, and injection of Tc-99m sestamibi after dobutamine infusion). Dobutamine echocardiography was abnormal in 36 patients (worsening resting wall motion abnormality in 11; new induced wall motion abnormality in 25). Dobutamine Tc-99m sestamibi tomoscintigraphy revealed a reversible perfusion defect in 34 patients, indicating the presence of myocardial ischaemia. As a result, eight patients underwent myocardial revascularization (n = 5) or the proposed operation was cancelled (n = 3). In the remaining 142 vascular procedures, there were eight (5.6%) adverse cardiac events: three myocardial infarctions (two fatal), three prolonged myocardial ischaemia, one acute congestive heart failure and one sustained ventricular arrhythmia in the post operative period. Univariate analysis selected unstable angina (relative risk (RR) 11.6), previous congestive heart failure (RR 6.4), Detsky's score of > or = 15 (RR 3.0), positive dobutamine stress echocardiography (RR 3.7), and positive dobutamine tomoscintigraphy (RR 7.4) as significant predictors of postoperative cardiac events. In patients without clinical markers of coronary artery disease (n = 66), non-invasive cardiac testing did not predict cardiac complications (n = 2; one prolonged myocardial ischaemia; one infarction). In the subset of 76 patients with definite clinical or electrocardiographic evidence of ischaemic heart disease, dobutamine stress testing provided additional information, and optimized risk stratification: five of six patients who suffered a cardiac complication had a pathologic dobutamine stress test. Furthermore, a negative dobutamine stress test was characterized by a high negative predictive value (0.96 for echocardiography; 0.97 for tomoscintigraphy). The study further demonstrated that the cardiac response (ischaemic versus non-ischaemic) to dobutamine stress was concordantly classified by echocardiographic and tomoscintigraphic techniques in 96% of cases. It is concluded that complementary non-invasive cardiac stress testing by dobutamine is indicated only in patients with clinically apparent coronary artery disease.

Aged↗

PubMed1996

Comparison of dobutamine transesophageal echocardiography and dobutamine magnetic resonance imaging for detection of residual myocardial viability.

A dobutamine-induced contraction reserve in akinetic but viable myocardium, observed by echocardiography or magnetic resonance imaging (MRI), is a reliable indicator of myocardial viability. However, the comparative diagnostic accuracy of these 2 techniques is unknown. Therefore, 43 patients with myocardial infarction (infarct age > or = 4 months) and regional akinesia underwent dobutamine transesophageal echocardiography (TEE) and dobutamine MRI (10 microg dobutamine/ min/kg). Both imaging techniques were compared with the reference standard 18F-fluorodeoxyglucose positron emission tomography (FDG PET). An infarct region was considered viable if a dobutamine contraction reserve could be assessed visually by TEE or quantitatively by MRI in > or = 50% of segments graded "a" or dyskinetic at rest. Infarct regions were graded viable by PET if FDG uptake was > or = 50% of the maximal FDG uptake in a region with normal wall motion by left ventriculography. A dobutamine contraction reserve was found in 21 of 43 patients (49%) by TEE and MRI. A viable infarct region by FDG PET was diagnosed in 26 of 43 patients (60%). FDG uptake and dobutamine TEE were concordant in 36 of 43 patients (84%) and dobutamine MRI and FDG PET were concordant in 38 of 43 patients (88%). Sensitivity and specificity of dobutamine TEE and dobutamine MRI for FDG PET-defined myocardial viability were 77% versus 81% and 94% versus 100%, respectively. Both imaging techniques yielded similar results for the detection of myocardial viability as defined by FDG uptake, with a slightly higher sensitivity and specificity for the quantitatively evaluated dobutamine contraction reserve by MRI.

Adrenergic beta-Agonists↗

PubMed2000

Head to head comparison of dobutamine-transoesophageal echocardiography and dobutamine-magnetic resonance imaging for the prediction of left ventricular functional recovery in patients with chronic coronary artery disease.

AIMS: A substantial number of patients with dysfunctional but potentially viable myocardium cannot be accurately evaluated by transthoracic echocardiography due to a poor acoustic window. This study compares the diagnostic value of alternative functional imaging techniques, such as dobutamine-transoesophageal echocardiography (dobutamine-TEE) and dobutamine magnetic resonance imaging (dobutamine-MRI) for the detection of viable myocardium and the prediction of left ventricular functional recovery in patients with chronic coronary artery disease following successful revascularization procedures. METHODS AND RESULTS: Rest and low-dose (5, 10 microg dobutamine x min(-1) x kg(-1)) multiplane dobutamine-TEE and ultrafast cine-MRI studies were performed in 103 patients. Contractile recovery of an infarct region was predicted if a dobutamine contraction reserve could be assessed visually by TEE or MRI in > or =50% of infarct-related a- or dyskinetic segments. Revascularization of the infarct-related vessel was successful in 88 patients, and 4.9 +/- 0.7 months later 52 patients still had an angiographically controlled open target vessel. These patients underwent another rest MRI study to assess left ventricular functional recovery. A dobutamine contraction reserve was observed in 27/52 (52%) patients by TEE and in 26/52 (50%) patients by MRI. Functional improvement of the infarct region was diagnosed in 28/52 (54%) patients. The positive and negative predictive accuracy of dobutamine-TEE and dobutamine-MRI for the prediction of left ventricular functional recovery was not significantly different (85% vs 92%, ns and 80% vs 85%, ns). Diagnosis of a predominantly viable infarct region by TEE and MRI predicted a significant increase in left ventricular ejection fraction (TEE: 12 +/- 8% vs 2 +/- 7% P<0.001, MRI: 13 +/- 7% vs 2 +/- 7%, P<0.001) compared to infarct regions graded as scar. CONCLUSION: A qualitative visual analysis of TEE and MRI viability studies is highly accurate for the prediction of left ventricular functional recovery in patients with dysfunctional myocardium and proved to be a clinically valuable alternative if transthoracic dobutamine-echocardiography is unsuitable. To date, TEE is cardiologists' preferred choice for the assessment of myocardial viability but MRI may become significantly more attractive with increasing local availability and experience.

Aged↗

PubMed1997

Effects of dobutamine stress on myocardial blood flow, 99mTc sestamibi uptake, and systolic wall thickening in the presence of coronary artery stenoses: implications for dobutamine stress testing.

BACKGROUND: Although dobutamine stress is used with both 99mTc sestamibi (sestamibi) myocardial perfusion imaging and echocardiography for detecting coronary artery stenoses, the impact of stenosis severity on test end points (myocardial sestamibi uptake and systolic thickening, respectively) has not been clearly defined. METHODS AND RESULTS: In 15 open-chest dogs, dobutamine (2.5 to 30 microg x kg(-1) x min(-1)) was infused after placement of an LAD stenosis that reduced (n=8) or abolished (n=7) flow reserve. In dogs with reduced flow reserve, the stenotic-to-normal sestamibi activity ratio (0.86+/-0.03) significantly underestimated the approximately 2-to-1 dobutamine-induced flow disparity at the time of sestamibi injection (flow ratio, 0.53+/-0.04; P<.001). Stenotic-zone thickening increased at low but not at higher doses of dobutamine (2.9+/-0.4 versus 4.2+/-0.4 mm in normal zone at peak dobutamine; P=.055) but did not fall below baseline (2.7+/-0.3 mm). Similarly, in dogs with absent flow reserve, the sestamibi activity ratio (0.78+/-0.02) underestimated the approximately 2.5-to-1 dobutamine-induced flow disparity (flow ratio, 0.41+/-0.05; P<.001), and failure to increase systolic thickening was observed in the stenotic zone (2.7+/-0.4 versus 4.6+/-0.3 mm in the normal zone at peak stress, P<.01). In both groups of dogs, myocardial sestamibi uptake and image defect magnitudes were less than expected for the dobutamine-induced hyperemia, suggesting that dobutamine adversely affects myocardial sestamibi binding. Finally, a significant reduction in stenotic-zone thickening was seen during postdobutamine recovery, consistent with myocardial stunning. CONCLUSIONS: In the presence of stenoses that reduced or abolished regional flow reserve, (1) myocardial sestamibi uptake significantly underestimated the dobutamine-induced flow heterogeneity, (2) a "failure to increase systolic thickening" rather than a reduction in thickening was observed during dobutamine stress, and (3) myocardial stunning was observed during postdobutamine recovery.

Analysis of Variance↗

PubMed1985

Effects of dopamine, (+/-)-dobutamine and the (+)- and (-)-enantiomers of dobutamine on cardiac function in pithed rats.

The effects of dopamine, (+/-)-dobutamine (racemic mixture) and the (+)- and (-)-enantiomers of dobutamine on myocardial function were evaluated in pithed rats. Dopamine and (+/-)-dobutamine produced effects on cardiac function in pithed rats that were qualitatively similar to those reported for these compounds in humans. The increase in cardiac output produced by dopamine and (+/-)-dobutamine was due mainly to an increase in stroke volume, with increases in heart rate contributing to a significant but lesser degree. For both dopamine and (+/-)-dobutamine, the increase in stroke volume appears to result from an increase in myocardial contractility as assessed by increases in left ventricular (LV) dp/dt. Dopamine produced a marked increase in mean arterial blood pressure, whereas (+/-)-dobutamine only modestly increased blood pressure. The (-)-enantiomer of dobutamine, which possesses mainly alpha-1 adrenoceptor agonist activity, produced dose-dependent increases in cardiac output, stroke volume, LVdp/dt and mean arterial blood pressure, but did not significantly increase heart rate except at high doses. Thus, the increase in cardiac output produced by (-)-dobutamine was derived almost exclusively from an augmentation in stroke volume resulting from an increase in myocardial contractility. In contrast, (+)-dobutamine, which possesses predominantly beta-1 and beta-2 adrenoceptor agonist activity, elicited only a modest increase in cardiac output which was due both to an increase in heart rate and stroke volume. Mean arterial blood pressure was not significantly affected by (+)-dobutamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

[Influence of image quality on the diagnostic accuracy of dobutamine stress magnetic resonance imaging in comparison with dobutamine stress echocardiography for the noninvasive detection of myocardial ischemia].

The analysis of wall motion abnormalities with dobutamine stress echocardiography is an established method for the detection of myocardial ischemia. With ultrafast magnetic resonance tomography, the application of identical stress protocols as used for echocardiography is possible. In 208 consecutive patients (147 M, 61 F) with suspected coronary artery disease, dobutamine stress echocardiography partially using harmonic imaging and dobutamine stress magnetic resonance tomography (DSMR) were performed prior to cardiac catheterization. DSMR images were acquired during short breath holds in 3 short axis-, a 4-, and a 2-chamber view using a turbo gradient echo technique. Patients were examined at rest and during a standard dobutamine-atropine scheme until submaximal heart rate was reached. Regional wall motion was assessed in a 16 segment model. Significant coronary heart disease was defined as angiographic >/=50% diameter stenosis. With DSMR, significantly more patients yielded very good (69%) or good (13%) image quality in comparison with dobutamine stress echocardiography (20% and 31%, p<0. 05). Moderate image quality occurred in 16% with MR and 41% with dobutamine stress echocardiography (p<0.05), 2% and 8% were non-diagnostic. With each technique 18 patients could not be examined (DSE: emphysema: 10, adipositas: 8, DSMR: claustrophobia: 11, adipositas: 6, contraindication: 1). Four patients did not reach target heart rate. In 107 patients, significant coronary artery disease was found. With DSMR sensitivity was 88.7% (dobutamine stress echocardiography: 74.3%; p<0.05) and specificity 85.7% (dobutamine stress echocardiography: 69.8%; p <0.05). This difference was most pronounced in the group with moderate echocardiographic image quality. High dose DSMR is superior to dobutamine stress echocardiography and can replace this technique especially in patients with moderate echocardiographic image quality.

Adult↗

PubMed1985

Systemic hemodynamic effects of dopamine, (+/-)-dobutamine and the (+)-and (-)-enantiomers of dobutamine in anesthetized normotensive rats.

The hemodynamic effects of dopamine, (+/-)-dobutamine (racemic mixture) and the (+)- and (-)-enantiomers of dobutamine were evaluated in anesthetized normotensive rats. Dopamine and (+/-)-dobutamine produced hemodynamic effects in anesthetized rat that were qualitatively similar to those reported for these compounds in man. The increase in cardiac output produced by dopamine and (+/-)-dobutamine was due mainly to an increase in stroke volume, with heart rate being only minimally affected. Dopamine produced a large increase in mean arterial pressure and slightly increased total peripheral vascular resistance, whereas (+/-)-dobutamine only modestly increased blood pressure and significantly reduced total peripheral resistance. The (-)-enantiomer of dobutamine, which possesses mainly alpha 1-adrenoceptor agonist activity, produced marked increases in cardiac output, stroke volume, total peripheral resistance and mean arterial pressure, but did not significantly increase heart rate. In contrast, (+)-dobutamine, which possesses predominantly beta 1-and beta 2-adrenoceptor agonist activity, elicited only a modest increase in cardiac output which was due entirely to increased heart rate since stroke volume was not increased. Total peripheral vascular resistance and mean arterial blood pressure were both reduced by (+)-dobutamine, characteristic of a beta-adrenoceptor agonist. The increase in cardiac output and blood pressure produced by (+/-)-dobutamine, but not the positive chronotropic effect, were significantly inhibited by alpha 1-adrenoceptor blockade with prazosin.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗

PubMed1995

Effects of dobutamine on myocardial blood flow, contractile function, and bioenergetic responses distal to coronary stenosis: implications with regard to dobutamine stress testing.

To determine the effects of dobutamine stimulation on myocardium distal to a coronary stenosis, transmural spatially localized phosphorus 31 nuclear magnetic resonance measurements of myocardial high-energy phosphate compounds (adenosine triphosphate and phosphocreatine), inorganic phosphate, and blood flow and systolic wall thickening were made in 8 open-chested dogs. Data were collected under (1) control conditions, (2) after the application of a moderate coronary stenosis, (3) during infusion of dobutamine with continuing stenosis, and (4) after the release of the stenosis with continuing dobutamine. Stenosis was associated with concordant reductions of subendocardial blood flow, wall thickening, and high-energy phosphate, and mild elevation of inorganic phosphate; subepicardial measurements were essentially unchanged. During dobutamine infusion, blood flow increased in all myocardial layers. Wall thickening returned to control values in the subendocardium and increased nonsignificantly in the subepicardium. Additional loss of high-energy phosphate occurred only in the subepicardium. The data suggest that improved contractile function associated with dobutamine infusion resulted from the inotropic effects of dobutamine and was made possible by the improved blood flow it produced. The data indicate that measurements of blood flow and contractile function do not reliably predict the transmural myocardial metabolic responses to inotropic perturbations in the hypoperfused heart. Taken together, the present findings yield insights with regard to the interpretation of diagnostic dobutamine stimulation testing with single photon emission tomography, radionuclide angiography, and echocardiography.

Animals↗

PubMed1999

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.

Journal Article↗

PubMed1996

Simultaneous dobutamine stress echocardiography and dobutamine scintigraphy (99mTc-MIBI-SPET) for assessment of coronary artery disease.

BACKGROUND: Simultaneous dobutamine stress echocardiography (DSE) and 99Tc-MIBI-SPET (DMS) for the evaluation of the presence and the extent of coronary artery disease (CAD) were assessed for a head to head comparison regarding the diagnostic acuracy of the two rests. METHODS AND RESULTS: Forty-five consecutive patients (33 males and 12 females: 53 +/- 6.8 yr.) underwent exercise electrocardiography and simultaneous dobutamine stress echocardiography and MIBI-SPET imaging. Coronary angiography was performed in all patients (significant coronary stenosis > 50%). On the basis of the results of exercise electrocardiogram the pre-test probability for coronary artery disease (Diamond's algorithm) was low (45.6 +/- 12.7%). The overall specificity, sensitivity and predictive accuracy of Echo-dobutamine stress test for diagnosis of the presence or absence of CAD were: specificity 82%, sensitivity 76%, diagnostic accuracy 80%, positive predictive value 90%, negative predictive value 40%. The overall specificity, sensitivity and predictive accuracy of MIBI-SPET-dobutamine test for diagnosis of the presence or absence of CAD were: specificity 86%, sensitivity 87%, diagnostic accuracy 84%, positive predictive value 97%, negative predictive value 54%. MIBI-SPET-dobutamine test showed a significantly higher sensitivity in comparison with ECHO-dobutamine test (P < 0.05). CONCLUSION: Both noninvasive methods for the detection of CAD showed a good diagnostic accuracy. Nevertheless the SPET model showed a higher sensitivity in comparison with DSE model, essentially in the presence of a lower extent of CAD and during submaximal test.

Cardiotonic Agents↗

PubMed1999

Comparison of dobutamine echocardiography, dobutamine sestamibi, and rest-redistribution thallium-201 single-photon emission computed tomography for determining contractile reserve and myocardial ischemia in ischemic cardiomyopathy.

Both dobutamine stress echocardiography (DSE) and myocardial perfusion scintigraphy are used to assess myocardial viability. Few studies have compared the data on myocardial viability and ischemia by low and peak dose DSE and myocardial perfusion imaging in the same patients. Fifty-four patients (45 men and 9 women aged 65 +/- 9 years) with ischemic cardiomyopathy (mean ejection fraction 24 +/- 9%) underwent rest 4-hour redistribution thallium-201 single-photon emission computed tomography (SPECT), low and peak dose DSE, and dobutamine sestamibi SPECT. A total of 864 segments were analyzed (16 segments/patient). Wall motion abnormality was present in 796 segments (92%), and contractile reserve during dobutamine infusion was seen in 400 of these segments (50%). Contractile reserve was seen in 331 of 509 hypokinetic segments (65%) and 69 of 287 akinetic/dyskinetic segments (24%) (p <0.001). Contractile reserve was more frequent in segments with normal thallium uptake (64%), reversible thallium defects (42%), or mild to moderate fixed thallium defects (48%) than severely fixed defects (22%) (p <0.05 each). Concordant information about viability by thallium imaging and DSE was obtained in 62% of segments. Dobutamine sestamibi ischemia was seen in 518 of 796 segments (65%) compared with 265 segments (33%) by DSE (p <0.001). Scintigraphic ischemia was noted in 126 of 195 segments (65%) demonstrating biphasic response, 129 of 205 segments (63%) showing sustained improvement, 42 of 70 segments (60%) deteriorating during dobutamine infusion, and 221 of 326 (68%) demonstrating no change (p = NS). Thus, in patients with ischemic cardiomyopathy, contractile reserve is more frequent in hypokinetic segments than akinetic/dyskinetic segments. The number of segments with normal or near-normal thallium uptake or with scintigraphic ischemia is significantly greater than the number of those capable of increasing contractile function or demonstrating an ischemic response during dobutamine echocardiography.

Adult↗

PubMed1995

Enhanced detection of myocardial ischemia by stress dobutamine echocardiography utilizing the "biphasic" response of wall thickening during low and high dose dobutamine infusion.

OBJECTIVES: We sought to assess the ability of the "biphasic" response (i.e., initial improvement in wall thickening followed by reduced wall thickening) during serial dobutamine stress echocardiography to detect ischemia in patients with a wall motion abnormality. Furthermore, we compared the power of the biphasic echocardiographic response with that of myocardial perfusion imaging for the detection of myocardial ischemia. BACKGROUND: Stress echocardiography has been shown to be less sensitive than radionuclide perfusion imaging for detecting ischemia in patients with a wall motion abnormality. Peak stress wall thickening in such areas may not give a full account of the intermediate changes, whereas initial improvement (the biphasic response) may enhance diagnosis. METHODS: Patients with a wall motion abnormality and documented coronary artery disease underwent simultaneous graded dobutamine (5 to 40 micrograms/kg body weight per min) stress echocardiography and radionuclide perfusion imaging with single-photon emission computed tomography using either technetium-99m sestamibi or technetium-99m tetrofosmin. Semiquantitative analyses of image groups were performed in blinded manner by two separate groups of observers. RESULTS: Myocardial ischemia was detected by perfusion imaging in 45 of the 54 patients. High dose dobutamine echocardiography detected ischemia in only 25 (56%) of these patients. However, when the biphasic response was taken into account, ischemia was detected in 44 (98%) of the 45 patients (p < 0.001). Agreement between radionuclide imaging and echocardiographic findings for the detection of ischemia was significantly enhanced (p = 0.03) when the biphasic response was used (89%, kappa = 0.51) instead of high dose stress dobutamine echocardiography (56%, kappa = 0.10). CONCLUSIONS: The detection of myocardial ischemia may be significantly enhanced by utilizing the biphasic response during serial stress dobutamine echocardiography in patients with a wall motion abnormality.

Aged↗

PubMed1997

Prognostic value of dobutamine-atropine stress echocardiography early after acute myocardial infarction. Echo Dobutamine International Cooperative (EDIC) Study.

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.

Adult↗

PubMed1984

Dobutamine and dopamine after cardiac surgery: greater augmentation of myocardial blood flow with dobutamine.

Left ventricular hemodynamics, dimensions and coronary sinus blood flows were measured simultaneously after infusions of dobutamine and dopamine. Ten patients were studied 6, 10 to 15, and 24 hr after cardiopulmonary bypass surgery. The dose of each drug was adjusted to increase cardiac output by 25%. Heart rate was held constant with atrial pacing. Dobutamine and dopamine increased peak left ventricular dP/dt from baseline values by 72% vs 58% during the early study, 77% vs 78% in the intermediate study, and 95% vs 79% in the late study (all NS, difference between drugs). Similarly, there were no significant differences in hemodynamic response or in cardiac dimensions after the two drugs in any period. Both drugs increased myocardial oxygen uptake during the intermediate and late studies (32% vs 33% and 34% vs 25%). With dobutamine this increase was matched by a similar increase in coronary blood flow; however, failure of the expected increase in coronary blood flow with dopamine suggested coronary constriction. Although dobutamine and dopamine have similar hemodynamic effects, dobutamine has the advantage of not limiting the increase in coronary blood flow associated with increased oxygen demand.

Catecholamines↗

PubMed1996

Comparative efficacy of short-term intravenous infusions of milrinone and dobutamine in acute congestive heart failure following acute myocardial infarction. Milrinone-Dobutamine Study Group.

The purpose of this study was to compare the hemodynamic and clinical effects of milrinone, a vasodilating and positive inotropic agent, with those of dobutamine in patients with congestive heart failure (CHF) following acute myocardial infarction (AMI). Thirty-three patients in Killip classification II or III within 12 h to 5 days after AMI were randomized in a multicenter, open-label clinical trial to receive a 24-h infusion of milrinone or dobutamine. Drugs were titrated to achieve at least a 30% increase in cardiac index (CI) from mean baseline or at least a 25% decrease in mean pulmonary capillary wedge pressure (MPCWP) from baseline. Both drugs improved CI, MPCWP, and other hemodynamic parameters. Criteria for decrease in MPCWP were met by 94% (15/16) of the milrinone-treated patients and 57% (8/14) of dobutamine-treated patients (p = 0.03). Both groups met the minimum efficacy criterion for CI. Maximal reduction in MPCWP over 0-3 h was greater in the milrinone group (-53.2%) than in the dobutamine group (-31.0%; p < or = 0.01); reductions were sustained over 24 h. Both drugs improved echocardiographic global ejection fraction and were generally well tolerated. The short-term infusion of milrinone may have a role in the management of CHF following AMI, especially when the aim is the rapid reduction of pulmonary congestion.

Acute Disease↗