The relation between transaortic pressure difference and flow during dobutamine stress echocardiography in patients with aortic stenosis

OBJECTIVE: To investigate the relation between transaortic pressure difference and flow in patients with aortic stenosis. METHODS: 50 asymptomatic patients with all grades of aortic stenosis were studied using dobutamine stress echocardiography. Individual plots of mean pressure drop against flow were drawn. Comparisons were made between grades of aortic stenosis as defined by the continuity equation. RESULTS: A significant linear relation between pressure difference and flow was found in 34 patients (68%). There was a significant curvilinear relation in four (8%), while no significant regression line could be fitted in 12 (24%). In the 34 patients with linear fits, the slopes (mean (SD)) were 0.08 (0.07) in mild, 0.10 (0.04) in moderate, and 0.22 (0.16) in severe aortic stenosis (p = 0. 0055). CONCLUSIONS: Transaortic pressure difference can be related directly to flow in many patients with all grades of aortic stenosis. However, there are individual differences in slope and intercept suggesting that resistance calculated at rest may not always be representative. Raw pressure drop/flow plots may be an alternative method of describing valve function.     

Safety and feasibility of dobutamine stress echocardiography in patients with implantable cardioverter defibrillators

Coronary artery disease is the underlying etiology of left ventricular dysfunction and arrhythmias in most patients who receive implantable cardioverter defibrillators (ICDs). The aim of this study was to assess the safety and feasibility of dobutamine stress echocardiography (DSE) in patients with an ICD. DSE (dobutamine up to 50 microg/kg/min, atropine up to 2 mg) was performed in 87 patients with an ICD and known or suspected coronary artery disease. The ICD was inactivated before the stress test and reactivated after the study; no serious complications occurred. DSE is a safe and feasible method for evaluating myocardial ischemia in patients with an ICD.     

Exhaled nitric oxide during exercise and dobutamine stress echocardiography in patients with mitral stenosis

BACKGROUND: Pulmonary hypertension (PH) is an important limiting factor of exercise tolerance in patients with mitral stenosis (MS). We wished to investigate the relationship between respiratory nitric oxide (NO), a potent vasodilator, and exercise tolerance in patients with moderate MS. In the same patients, we wondered whether acute change in pulmonary hemodynamics could affect respiratory NO. METHODS: Ten patients with moderate MS (valve area 1.4+/-0.2 cm(2)) were studied at rest, during incremental cycle ergometry exercise, and during dobutamine stress echocardiography (DSE). The concentration of NO in exhaled air (FE(NO)) and NO output (V'(NO)) were measured at baseline, at the end of exercise, and at the end of DSE. Eight healthy subjects served as normal controls for NO output during exercise. RESULTS: During exercise, FE(NO) decreased both in patients and in controls, while V'(NO) increased in both. At the end of exercise, both VO(2) max and V'(NO) were significantly higher in controls than in patients. The increase in V'(NO) during exercise was significantly correlated with VO(2) max, both in patients and in controls. During DSE, cardiac output (CO), pulmonary artery pressure (PAP), and mitral valve gradient increased. No changes in mean FE(NO), V'(NO), or ventilation were observed during DSE. There was a significant inverse correlation between FE(NO) and mitral valve gradient at the end of DSE. CONCLUSIONS: In patients with moderate MS, exercise performance is correlated with respiratory NO output. In the same patients, during DSE, the increase in CO, which is not accompanied by an increase in ventilation, is not associated with an increase in respiratory V'(NO).     

Safety and feasibility of dobutamine and dipyridamole stress echocardiography in hypertensive patients

OBJECTIVES : To establish whether safety and feasibility of dobutamine and dipyridamole stress echocardiography are affected by history of hypertension. METHODS : Data on 2200 consecutive pharmacologic stress echocardiography (959 dobutamine and 1241 dipyridamole) performed between October 1990 and February 2001 at a single cardiology centre, were analysed. RESULTS : There were two complications (1/480 tests) during dobutamine (one sustained ventricular tachycardia and one severe asthmatic attack following antidote administration) and two (1/620 tests) during dipyridamole (one non-Q wave myocardial infarction and one sustained ventricular tachycardia) stress. Complications or limiting side effects were observed in 83/959 patients (48/430 hypertensives and 35/529 normotensives) with dobutamine and in 34/1241 patients (17/571 hypertensives and 17/670 normotensives) with dipyridamole stress. Therefore, the overall feasibility was 88.8% in hypertensives and 93.4% in normotensives (P = 0.013) for dobutamine, and 97% in hypertensives and 97.5% in normotensives (P = 0.64) for dipyridamole. Dipyridamole was significantly more feasible than dobutamine in both hypertensive (P < 0.0001) and normotensive (P = 0.0006) subjects. Logistic regression analysis failed to identify clinical or echocardiographic predictors of adverse reactions with dipyridamole, while history of hypertension [odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.1-2.8, P = 0.0138] was the only independent predictor of cumulative adverse reactions with dobutamine stress. In addition, history of hypertension (OR = 3.2, 95% CI, 1.2-8.5, P = 0.0166), resting wall motion abnormalities (OR = 1.8, 95% CI, 1.1-3.1, P = 0.0282), and age over 70 years (OR = 4.8, 95% CI, 1.5-15.3, P = 0.0087) predicted hypertensive response, ventricular tachycardia, and atrial fibrillation, respectively. No covariate was associated with hypotensive response during dobutamine test. CONCLUSIONS : Dipyridamole has a slightly better safety profile and significantly higher feasibility than dobutamine stress both in hypertensives and in normotensives. In addition, the history of systemic hypertension is an independent predictor of cumulative adverse effects during dobutamine but not during dipyridamole stress.     

Safety of dobutamine stress real-time myocardial contrast echocardiography

OBJECTIVES: The aim of this study was to determine the safety of dobutamine stress myocardial perfusion imaging (MPI) obtained by real-time contrast echocardiography (RTCE) and intravenous ultrasound contrast in a large cohort of patients with suspected coronary artery disease (CAD). BACKGROUND: Despite the increasing number of studies showing the potential clinical utility of myocardial contrast perfusion imaging with commercially available contrast agents, the safety of this technique in a clinical setting has not been demonstrated. METHODS: Over a four-year period, 1,486 patients underwent dobutamine stress RTCE with low mechanical index pulse sequence schemes after intravenous injections of commercially available contrast agents (35% Definity, Bristol Myers Squibb Medical Imaging Inc., North Billerica, Massachusetts; 65% Optison, GE-Amersham, Princeton, New Jersey). The hemodynamic and adverse effects of RTCE were compared with 1,012 patients who underwent conventional dobutamine stress echocardiography (DSE) without contrast. The feasibility of image analysis was defined as the ability to analyze MPI in at least two of the three standard segments in each left ventricular wall. RESULTS: No myocardial infarction or death occurred during dobutamine stress. There was no difference in the incidence of nonsustained ventricular tachycardia, sustained ventricular tachycardia, or supraventricular tachycardia during dobutamine infusion between RTCE and DSE. Myocardial perfusion imaging was considered feasible for analysis in 94% of the walls at baseline and 95% at peak stress. The anterior, lateral, and posterior walls were the most common regions in which MPI was not feasible. Myocardial perfusion imaging with RTCE had a higher accuracy for detecting patients with angiographically significant CAD than the analysis of wall motion (84% vs. 66%, respectively; p < 0.001). CONCLUSIONS: Dobutamine stress RTCE appears to be a safe and feasible technique for evaluating patients with known or suspected CAD.     

Real-time three-dimensional dobutamine stress echocardiography in assessment stress echocardiography in assessment of ischemia: comparison with two-dimensional dobutamine stress echocardiography

OBJECTIVES: This study was designed to test the feasibility and efficacy of using real-time three-dimensional echocardiography (RT-3D) to detect ischemia during dobutamine-induced stress (DSE) and compares the results with conventional two-dimensional echocardiography (2D). BACKGROUND: Real-time three-dimensional echocardiography, a novel imaging technique, offers rapid acquisition with multiple simultaneous views of the left ventricle (LV). These features make it attractive for application during stress. METHODS: Of 279 consecutive patients screened for image quality by 2D, 253 patients with adequate images underwent RT-3D and 2D within 30 s of each other at baseline and at peak DSE. RESULTS: Real-time three-dimensional echocardiography and 2D showed good concordance in detection of abnormal LV wall motion at baseline (84%: Kappa = 0.59) and at peak DSE (88.9%: Kappa = 0.72). Left ventricular wall motion scores were similar at baseline and peak DSE using both techniques. Interobserver agreements for detection of ischemia at peak DSE were superior for RT-3D, 92.7% compared with 84.6% for 2D (p < 0.05). Mean scanning time at peak stress by RT-3D in 50 randomly selected patients was shorter, 27.4 +/- 10.7 s compared with 62.4 +/- 20.1 s by 2D (p < 0.0001). In 90 patients with coronary angiograms, RT-3D had a sensitivity of 87.9% in the detection of coronary artery disease (CAD) compared with 79.3% by 2D. CONCLUSIONS: Real-time three-dimensional dobutamine stress echocardiography is feasible and sensitive in the detection of CAD. The procedure offers shorter scanning time, superior interobserver agreements and unique new views of the LV.     

Results of dobutamine stress echocardiography in patients with Syndrome X

This study describes the results of Dobutamine stress echocardiography in 10 patients with Syndrome X. The diagnosis of Syndrome X was made on the basis of the presence of exertional angina, positive exercise stress test, negative ergonovine stress test and normal coronary arteries at angiography. All patients underwent Dobutamine stress echocardiography after interruption of any antianginal therapy. Dobutamine was infused starting with a dose of 5 mcg/kg/min over 3 minutes with incremental steps of 5 mcg/kg/min every 3 minutes up to a maximal dose of 40 mcg/kg/min. Two-dimensional echocardiography and 12-lead electrocardiography was monitored during the infusion of the drug. Nine patients received the maximal dose while one patient prematurely stopped the test for the occurrence of side effects. None of the ten patients developed segmental left ventricular wall motion abnormalities indicative of myocardial ischemia; ST-segment depression diagnostic for ischemia developed in 30% of patients; angina was elicited in one of these patients and in two additional patients. A hyperkinetic response to Dobutamine infusion involving all the segments of the left ventricle was observed both in patients with and without chest pain or electrocardiographic changes.In patients with Syndrome X Dobutamine induces a hyperkinetic left ventricular response indicative of normal contractile reserve despite the presence in some cases of angina and electrocardiographic signs of ischemia.     

Usefulness of dobutamine stress echocardiography in a patient with aortic valve stenosis and left ventricular dysfunction: a case report

A 76-year-old man with previous antero-septal myocardial infarction and aorto-coronary bypass surgery developed exertional dyspnea. Echocardiography revealed diffuse left ventricular hypokinesis and aortic stenosis with a mean pressure gradient of 29 mmHg. Coronary angiography showed no significant lesions in the bypass grafts and total occlusions of the proximal left anterior descending artery and mid circumflex artery. Dobutamine stress echocardiography was performed to evaluate the severity of aortic stenosis and left ventricular functional reversibility. Administration of dobutamine increased the mean pressure gradients to 48 mmHg and increased the stroke volume by 28% without change in aortic valve area of about 0.5 cm2. We considered that our patient had severe aortic stenosis with contractile reserve. After aortic valve replacement, he improved with better left ventricular function.     

Echocardiographic predictors of hemodynamic response and significance of dyspnea development in patients with mitral stenosis during dobutamine stress echocardiography

BACKGROUND AND AIM OF THE STUDY: In mitral stenosis (MS) patients, resting hemodynamic data do not always correlate with symptom severity. Stress tests may be carried out in these patients, but the mechanisms of different hemodynamic and clinical responses to stress are not clearly established. The study aim was to evaluate hemodynamic changes that correlate with dyspnea development during dobutamine infusion (DI) in patients with MS, and to assess determinants of transmitral gradient response. METHODS: Forty-five consecutive mild or moderately symptomatic patients (36 women, nine men; mean age 44 +/- 10 years; range: 26-66 years), in NYHA class II and with MS (mean mitral valve area (MVA) 1.6 +/- 0.1 cm2; range: 1.5-1.9 cm2) were evaluated with dobutamine stress echocardiography. RESULTS: During DI, dyspnea developed in 12 patients, and 33 patients remained asymptomatic. During infusion, both mean transmitral gradient (6 +/- 3 versus 11 +/- 6 mmHg, p = 0.01) and pulmonary artery systolic pressure (PASP) (13 +/- 4 versus 21 +/- 3 mmHg, p < 0.001) were significantly increased in patients who developed dyspnea compared to others. Hence, a subgroup of patients with more serious MS was identified using the hemodynamic response to dobutamine. Based on these clinical and hemodynamic results, management was changed in 12 patients (27%); five underwent percutaneous mitral balloon commissurotomy and seven received intensive medical treatment. In all patients, PASP at rest (p = 0.001), MVA (p < 0.0001) and subvalvular mitral score (p = 0.004), which is indicative of mitral valve damage, were significantly correlated with mean mitral valve gradient response. CONCLUSION: These results suggest that patients in whom dyspnea is provoked during DI show a greater increase in hemodynamic parameters than patients in whom provocation does not occur. The mean mitral valve gradient-response correlates with baseline pulmonary artery pressure, MVA and subvalvular echo score, and may be predicted by these parameters. Association between dyspnea and presence of severe mitral valve hemodynamics showed a high sensitivity and negative and positive predictive value. It is possible that dyspnea may be of value in identifying those patients with significant mitral valve obstruction.     

超声心动图在主动脉瓣狭窄经导管主动脉瓣植入术中的应用价值

目的探讨超声心动图在主动脉瓣狭窄患者经导管主动脉瓣植入术中的作用。方法3例重度主动脉瓣瓣膜狭窄患者接受经导管主动脉瓣人工瓣膜植入术。使用PhilipS iE33型彩色多普勒超声诊断仪,配备经胸探头S5—1和经食道探头S7—2,X7—2t。超声观察内容包括明确主动脉瓣膜病变范围和程度,测量主动脉瓣环前后径,人工瓣膜植入术后瓣膜功能等。结果3例患者经导管主动脉瓣植入术均取得了成功,人工瓣膜位置稳定,常规超声心动图3例患者术前经胸超声心动图与术中经食管超声心动图诊断相符,跨瓣压差较术前明显下降,主动脉瓣瓣上流速明显下降,瓣周漏瞬时反流量平均约1．2mL。结论经导管主动脉瓣人工瓣膜植入术在治疗严重主动脉瓣瓣膜狭窄中方法可行,效果良好;超声心动图在这项工作中具有重要的辅助作用。     

Long-term prognostic value of dobutamine stress echocardiography in patients with atrial fibrillation

STUDY OBJECTIVE: To assess the long-term prognostic value of dobutamine stress echocardiography (DSE) for cardiac events (cardiac death, myocardial infarction, and late revascularization) in patients with atrial fibrillation (AF). METHODS: Baseline ECGs were studied in patients undergoing DSE between 1989 and 1998. Sixty-nine patients had AF before DSE. Prognostic value of DSE in these patients was compared with a control group who had sinus rhythm (n = 1,664). The presence of stress-induced ischemia was noted for every patient. The mean follow-up period was 35 months (range, 6 to 84 months). Data are presented as hazards ratio (HR) with 95% confidence interval (CI). RESULTS: Heart rate at rest was higher in patients with AF (77 +/- 15 beats/min vs 73 +/- 14 beats/min; p = 0.04); however, double product at peak stress was not different between patients with AF and sinus rhythm (17,602 vs 17,169, respectively; p = 0.46). In patients with AF, target heart rate was achieved at a lower dobutamine dose (33 +/- 8 microg/kg/min vs 35 +/- 9 microg/kg/min; p = 0.01). Cardiac arrhythmias occurred more frequently (12% vs 5%; p = 0.001) in patients with AF during DSE. During a follow-up period of 7 years, cardiac death occurred in 5 patients, myocardial infarction in 2 patients, and late revascularization in 10 patients. Prognostic value of DSE for all late cardiac events was similar in patients with AF (HR, 3.0; 95% CI, 0.9 to 9.5) and sinus rhythm (HR, 3.4; 95% CI, 2.7 to 4.3; p = 0.85). CONCLUSION: The prognostic value of DSE for late cardiac events is maintained in patients with AF.     

Safety of dobutamine stress transesophageal echocardiography in obese patients for evaluation of potential ischemic heart disease

The purpose of this study was to determine the safety of dobutamine stress transesophageal echocardiography (DS-TEE) in the evaluation of potential coronary artery disease in obese patients. Obese patients tend to have a higher prevalence of hypertension, coronary artery disease, and sleep apnea conditions that could potentially predispose to complications during endoscopic procedures such as DS-TEE. In addition, obese patients are more likely to have oxygen desaturation during upper gastrointestinal endoscopy. Thus, the safety of DS-TEE in 90 obese patients (body mass index (BMI) > or = 27.5 kg/m2) and 86 nonobese patients (BMI < 27.5 kg/m2) was compared. Minor complications (i.e., complications of transient duration and requiring no or only simple intervention) occurred with almost equal frequency in the nonobese and obese groups (28% vs. 29%, P = ns). Transient hypotension was observed in 9% of the obese group compared to 22% in the nonobese group (P < 0.025). However, transient hypertension was noted in 20% of the obese patients compared to 6% in the nonobese group (P < 0.01). A major complication occurred in three obese patients (3.3%), which included hypotension, marked elevation of systolic blood pressure, or ventricular fibrillation. Four patients (4.7%, P = ns) of the nonobese group had a major complication, which included sustained ventricular tachycardia in one, hypertension in one, and hypotension in two patients. No deaths occurred in either group. Although obesity should remain a consideration in the risk assessment of whether or not to perform DS-TEE, when proper precautions are instituted DS-TEE appears equally safe in obese as compared to nonobese patients.