Use Of Dobutamine Stress Echocardiography Research Articles

Dobutamine Stress Echocardiography in Low-Gradient Aortic Stenosis

Guidelines recommend the use of dobutamine stress echocardiography (DSE) in patients with low-gradient aortic stenosis (AS) and left ventricular ejection fraction (LVEF)<50%. However, a paucity of DSE data exists when LVEF >35%. To examine the diagnostic accuracy of DSE in patients with low-gradient AS with a wide range of LVEF and to examine the interaction between the diagnostic accuracy of DSE and LVEF. Patients with mean gradient <40mm Hg, aortic valve area <1.0cm2, and stroke volume index ≤35mL/m2 undergoing DSE and cardiac computer tomography (C-CT) were identified from 3 prospectively collected patient cohorts and stratified according to LVEF: LVEF<35%, LVEF 35% to 50%, and LVEF>50%. Dobutamine stress echocardiography and C-CT were performed on patients with low-gradient AS. Severe AS was defined as aortic valve calcification score ≥2,000 arbitrary units (AU) among men and ≥1,200 AU for women on C-CT. Of 221 patients included in the study, 78 (35%) presented with LVEF <35%, 67 (30%) with LVEF 35% to 50%, and 76 (34%) with LVEF >50%. Mean-gradient and aortic valve peak velocity during DSE showed significant diagnostic heterogeneity between LVEF groups, being most precise when LVEF <35% (both areas under the curve [AUC]=0.90), albeit with optimal thresholds of 30mm Hg and 377cm/sec and a limited diagnostic yield in patients with LVEF ≥35% (AUC=0.67 and 0.66 in LVEF 35% to 50% and AUC=0.65 and 0.60 in LVEF ≥50%). Using guideline thresholds led to a sensitivity/specificity of 49%/84% for all patients with LVEF <50%. While DSE is safe and leads to an increase in stroke volume in patients with low-gradient AS regardless of LVEF, the association between DSE gradients and AS severity assessed by C-CT demonstrates important heterogeneity depending on LVEF, with the highest accuracy in patients with LVEF <35%.

Abstract 15165: Dobutamine Stress Echocardiography in Patients With Low Flow, Low Gradient Aortic Stenosis and Preserved Lvef

Introduction: Guidelines recommend the use of Dobutamine stress echocardiography (DSE) in case of low flow low gradient aortic stenosis (LFLG AS) when left ventricular ejection fraction (LVEF) &lt;50%, but few data support this threshold as most studies have tested DSE when LVEF &lt;35%. Hypothesis: To examine the feasibility of DSE in patients with LFLG AS, and the possible interaction between LVEF and accuracy of projected aortic valve area (AVA proj ) in correctly classifying severe AS defined by Cardiac Computer Tomography (C-CT). Methods: Patients with LFLG AS (aortic mean gradient &lt;40 mmHg &amp; AVA &lt;1.0 cm 2 &amp; stroke volume index (SV i ) &lt;35ml/m 2 ) undergoing DSE were identified from two prospective cohorts, and stratified according to LVEF (&lt;35%, 35-50% and &gt;50%). Severe AS was defined as AVC score ≥2000 AU in males, and ≥1200 AU in females on C-CT. Results: Of 214 patients, 65 (30%) presented with LVEF &lt;35%, 58 (27%) with LVEF 35-50%, and 91 (43%) with LVEF &gt;50%. 97 patients presented with severe AS (32 vs 21 vs 44, p=0.26). An inverse relationship was seen between LVEF and left ventricular diameter (60±10mm vs 54±7mm vs 47±6mm, p&lt;0.01). Although resting SV i was different between groups (26.4±6.4mL vs 27.3±5.6 vs 29.6±5.7, p&lt;0.01), no significant differences in SV i change was seen during DSE (7.3±5.9mL vs 5.5±6.2mL vs 6.7±6.7mL, p=0.30), and patients with LVEF &lt;35% were more likely to demonstrate flow-reserve, defined as an increase in SVi &gt;20%; 39 (63%) vs 21 (36%) vs 44 (49%), p=0.01. AVA proj provided similar AUCs (p=0.31) (Figure 1) and cut-off points in classifying severe AS across LVEF groups: LVEF&lt;35%: 1.02 cm 2 /accuracy 74%, vs LVEF 35-50%: 0.82cm 2 /accuracy 72% vs LVEF &gt;50%: 0.9cm 2 /accuracy 65%. Conclusion: DSE leads to similar increases in stroke volume index (SV i ) in patients with LVEF &gt;50% compared with LVEF ≤50%. Furthermore, the projected aortic valve area (AVA proj ) provides good accuracy for identification of true-severe AS, regardless of LVEF stratum.

Cardiac Risk Stratification in Liver Transplantation: Results of a Tiered Assessment Protocol Based on Traditional Cardiovascular Risk Factors.

Coronary artery disease (CAD) confers increased perioperative risk in patients undergoing liver transplantation (LT). Although routine screening for CAD is recommended, there are limited data on the effectiveness of screening strategies. We evaluated the safety and efficacy of a 3-tiered cardiac risk-assessment protocol that stratifies patients based on age and traditional cardiac risk factors. We peformed a single-center, prospective, observational study of consecutive adult patients undergoing LT assessment (2010-2017). Patients were stratified into low-risk (LR), intermediate-risk (IR), or high-risk (HR) cardiac groups and received standardized investigations with selective use of transthoracic echocardiography (TTE), dobutamine stress echocardiography (DSE), computed tomography coronary angiography (CTCA), and coronary angiography (CA). Primary outcomes were cardiac events (CEs) and cardiovascular death up to 30 days after LT. Overall, 569 patients were included, with 76 patients identified as LR, 256 as IR, and 237 as HR. Cardiac risk factors included diabetes mellitus (26.0%), smoking history (47.3%), hypertension (17.8%), hypercholesterolemia (7.2%), family (17.0%) or prior history of heart disease (6.0%), and obesity (27.6%). Of the patients, 42.0% had ≥2 risk factors. Overall compliance with the protocol was 90.3%. Abnormal findings on TTE, DSE, and CTCA were documented in 3, 23, and 44 patients, respectively, and 12 patients were not listed for transplantation following cardiac assessment (1 LR, 2 IR, and 9 HR). Moderate or severe CAD was identified in 25.4% of HR patients on CTCA following a normal DSE. CEs were recorded in 7 patients (1.2%), with 2 cardiovascular deaths (0.4%). Cardiac risk stratification based on traditional cardiac risk factors with the selective use of DSE, CTCA, and CA is a safe and feasible approach that results in a low perioperative cardiac event rate.

Diagnostic accuracy of dobutamine stress echocardiography in the detection of cardiac allograft vasculopathy in heart transplant recipients: A systematic review and meta-analysis study.

Dobutamine stress echocardiography (DSE) is a well-established imaging modality used to screen patients with mild-to-moderate risk for coronary artery disease. In heart transplantation recipients, cardiac allograft vasculopathy (CAV) is a common and lethal complication. The use of DSE to detect CAV showed promising results initially, but later studies showed limitation in its use to detect CAV. It is unclear if this cohort of patients derives benefit from DSE. We searched PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and Scopus from inception through March 2018 for studies examining the accuracy of DSE in correlation to coronary angiography (CA) or intravascular ultrasound (IVUS) to detect CAV. Original studies comparing the ability of DSE to detect CAV in comparison with CA or IVUS were included. Relevant data were extracted and hierarchical summary receiver operating characteristic analysis was conducted to test the overall diagnostic accuracy of DSE for patients with CAV. Eleven studies (749 participants) met the inclusion criteria. The sensitivity of DSE varied from 1.7% to 93.8%, and specificity, from 54.8% to 98.8%. Pooled sensitivity was 60.2% (95% confidence interval (CI), 33.0%-82.3%) and specificity 85.7% (95% CI, 73.8%-92.7%). DSE had an overall diagnostic odds ratio (OR) of 9.1 (95% CI, 4.6-17.8), positive likelihood ratio (LR+) of 4.1 (95% CI, 2.8-6.1), negative likelihood ratio (LR-) of 0.47 (95% CI: 0.23-0.73), and area under curve (AUC) of 0.73 (95% CI, 0.72-0.75). Heterogeneity among studies was not statistically significant (τ2 =0.32, Cochran's Q=9.5, P=0.483). Dobutamine stress echocardiography has a limited sensitivity to detect early CAV but its specificity is much higher. There remains a need for an alternative noninvasive modality which will have both high sensitivity and high specificity for detecting CAV.

Cardiac Events after Noncardiac Surgery in Patients Undergoing Preoperative Dobutamine Stress Echocardiography: Findings From the Mayo Poce-DSE Investigators

BackgroundCurrent guidelines support the use of dobutamine stress echocardiography (DSE) prior to noncardiac surgery in higher-risk patients who are unable to perform at least 4 metabolic equivalents of physical activity. We evaluated postoperative outcomes of patients in different operative risk categories after preoperative DSE. MethodsWe collected data from the medical record on 4494 patients from January 1, 2006 to December 31, 2011 who had DSE up to 90 days prior to a noncardiac surgery. Patients were divided into low, intermediate, and high preoperative surgery-specific risk. Baseline demographic data and risk factors were abstracted from the medical record, as were postoperative cardiac events including myocardial infarction, cardiac arrest, and mortality within 30 days after surgery. ResultsThere were 103 cardiac outcomes (2.3%), which included myocardial infarction (n = 57, 1.3%), resuscitated cardiac arrest (n = 26, 0.6%), and all-cause mortality (n = 40, 0.9%). Cardiac event rates were 0.0% (95% confidence interval [CI], 0.0%-3.9%) in the low-surgical-risk group, 2.1% (95% CI, 1.6%-2.5%) in the intermediate-surgical-risk group, and 3.4% (95% CI, 2.0%-4.4%) in the high-risk group. Thirty-day postoperative mortality rates were 0%, 0.9%, and 0.8% for the low-risk, intermediate-risk, and high-risk surgical groups, respectively, and were not statistically different. ConclusionsThese findings demonstrate low cardiac event rates in patients who underwent a DSE prior to noncardiac surgery. The previously accepted construct of low-, intermediate-, and high-risk surgeries based on postoperative events of <1%, 1%-5%, and >5% overestimates the actual risk in contemporary settings.

The Value of Using Pulsed Tissue Doppler Mitral Annulus Velocity during Dobutamine Stress Echocardiography for Assessment of Myocardial Viability in Patients with Coronary Artery Disease before Revasularization

Background: Assessment of viability could be of significance in ischemic and heart failure patients before deciding for revascularization. The use of Dobutamine stress echocardiography has the disadvantage of subjective visual evaluation of regional wall motion, so, new technologies have been modified; one of these is to assess mitral annular velocity using tissue Doppler imaging. Aim: The aim of this study was to evaluate the value of Pulsed wave tissue Doppler mitral annulus velocity with dobutamine echocardiography in assessment of myocardial viability and prediction of functional recovery of wall motion abnormalities after revasularization in patients with coronary artery disease. Patients and methods: The study group included 40 patients, selected consecutively from patients presented to Ain Shams university Hospitals with coronary artery disease as proved by diagnostic coronary angiography and recommended for potential coronary revascularization. Each patient underwent baseline transthoracic echocardiography, in addition to low dose dobutamine echocardiography using TDI at mitral annulus in 6 different walls. All patients were subjected to revascularization (30 by PCI and 10 by CABG) then followed up after 6 months by transthoracic echocardiography to assess improvement in EF and SWMA. Results: Using the 16 segment method, a total of 640 segments were studied: 250 Segments were considered nondysfunctional (39%), 390 Segments were dysfunctional: of which, severely hypokinetc (216, 55.4 % of abnormal), 158 segments akinetic (40.5% of abnormal), and 16 Segments were dyskinetic (4.1% of abnormal). The mean SWM index at rest was 1.9 (0.39).Using low dose dobutamine echocardiography, 220 segments were detected to be viable (56.4%), while 170 were non-viable (43.6%). In order to relate the results of TDI, The 16 segments were reevaluated into 6 walls per patient. Using this method, 240 walls were studied. 19 walls were excluded due to technical difficulties in assessment of TDI. Pulsed wave TDI demonstrated that dysfunctional areas had lower systolic velocities compared to areas considered as normal. Similarly, the increase from baseline to DSE (ΔTDI) was higher in nondysfunctional areas vs. dysfunctional areas. However, there was no significant difference in the mean TDI at rest for viable and non-viable walls as detected by dobutamine stress echocardiography. But the increase in TDI velocity with peak dobutamine was significantly more in viable (1.97±0.44) vs. nonviable (1.14±0.54) walls, with p<0.0001.The ejection fraction improved from 39.87±8.22 (mean + STD) at baseline to 46.13±8.58 (mean + STD) at follow-up. The score index of the segmental wall motion during follow up after revascularization was 1.45±0.29 (mean+STD). Among the total dysfunctional segments detected at baseline echocardiography, follow-up echo postoperatively showed improvement by ≥1 score in 239 segments (61.3 %).In the 220 dobutamine positive segments, 182 segments improved postrevacsularization (82.7%) while 38 did not show improvement (17.3%), whereas in the segments designated as dobutamine non-viable, 122 segments were not improved (71.8%) and 48 segments (28.2%) improved post revascularization. Taking improvement as the gold standard for viability, sensitivity of dobutamine is: 82.7%, specificity 71.8%, PPV 79.1%, NPV 76.3%. Using TDI method, 115 (79.3%) walls were diagnosed as viable by this method, while 30 walls were nonviable (20.7%). 80 walls (55.2% of total studied walls) were detected to be viable by both dobutamine conventional 2D echocardiography and dobutamine TDI echocardiography (systolic wave), On the other hand, 27 walls (18.6% of total studied walls) were detected to be non-viable by both methods. However, 38 walls (26.2% of total abnormal walls) showed discordance between the two methods. The improvement of 74 walls of 80 combined TDI& DSE positive walls, making a sensitivity of 90.2%, similarly 24 of 27 concordant TDI & DSE negative walls did not improve, making a specificity of 92.3%. Conclusion: The current study confirmed the importance of using TDI in different mitral annular sites, as an objective tool in detecting myocardial viability, and to improve the sensitivity and specificity of DSE.

Vulnerability to Sympathetic Stress Does Not Persist in Takotsubo Stress Cardiomyopathy

ObjectiveOur objective was to investigate whether dobutamine stress echocardiography (DSE) could induce abnormal cardiac function in takotsubo stress cardiomyopathy (TSC) patients in a stable condition after the acute attack. Methods and ResultsThis was a case-control study and a substudy of the Stockholm Myocardial Infarction With Normal Coronaries (SMINC) study. Twenty-two patients with a previous episode of TSC and 22 sex- and age-matched control subjects were recruited from the SMINC study and investigated with the use of DSE. All TSC patients had a previous normal cardiovascular magnetic resonance investigation. Tissue Doppler imaging–derived time phases of the cardiac cycle were recorded to calculate myocardial performance index (MPI) to assess ventricular function. Compared with control subjects at rest, TSC patients had a slightly but significantly higher left ventricular MPI (LV-MPI; 0.53 vs 0.59; P = .01) and as a trend higher right ventricular MPI (0.38 vs 0.47; P = .08), although during DSE these variables did not differ significantly. ConclusionWe found no difference in standard diastolic parameters between TSC and control subjects, but a significant higher value in LV-MPI in the TSC group at rest. However, no such difference could be demonstrated during DSE between the groups, indicating that vulnerability to sympathetic stimulation does not persist in TSC patients.

Low-dose dobutamine stress echocardiography cannot predict mitral regurgitation reversibility after coronary artery bypass grafting

The ideal management of ischemic mitral regurgitation (MR) remains a clinical dilemma because of the suboptimal available therapeutic options. Recently, new concepts have emerged, pointing to the benefits of a patient selection approach when debating the management of moderate ischemic MR. We investigated the predictability of low-dose dobutamine stress echocardiography (DSE) in selecting candidates for CABG with moderate MR for valve repair. From November 2002 to May 2010, 110 candidates for first-time CABG, who were admitted to the cardiac surgery department in Day General Hospital (Tehran, Iran), were enrolled in the present cross-sectional study. DSE was performed for each case before CABG. Those with positive findings underwent CABG alone and those with negative results underwent concomitant CABG and mitral valve repair. The patients were followed up for a minimum of 60 months. Of the 110 patients, 47 (42.72%) had positive test results and underwent CABG alone and 63 (57.28%) had negative DSE results and underwent concomitant CABG and mitral valve repair. The MR degree had decreased from 2.8±0.3 preoperatively to 1.46±0.6 early during the hospital stay and 1.9±0.7 during late follow-up in the CABG group. It had decreased from 2.84±0.4 preoperatively to 0.93±0.65 postoperatively but then increased to 1.41±0.9 during late follow-up, for a significant decrease in the combined group (P<.05). Despite its utility in selecting CABG patients with moderate ischemic MR for valve repair from a short-term perspective, the use of DSE cannot predict the long-term outcomes of these patients.

Dobutamine stress echocardiography in patients undergoing orthotopic liver transplantation: a pooled analysis of accuracy, perioperative and long term cardiovascular prognosis

Pre-transplant evaluation for orthotopic liver transplantation (OLT) commonly includes a cardiac evaluation using dobutamine stress echocardiography (DSE). We performed a quantitative systematic review assessing DSE's use in detecting coronary artery disease (CAD) and predicting perioperative and long term cardiac events in patients undergoing OLT. Published studies in pubmed were accessed using keyword searches and bibliographic review. Included studies evaluated the use of DSE in patients undergoing OLT, including its accuracy for detection of CAD, and in predicting perioperative and long term cardiac prognosis for both hard (myocardial infarction, cardiac death, cardiac arrest, and asystole) and soft cardiac events (all other events that were cardiovascular in nature). We calculated DSE's sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) in the above areas. We identified 7 studies, including a total of 580 patients, which included 4 accuracy studies (n=110 patients), 4 perioperative studies, and 3 long term studies. Accuracy for CAD included a sensitivity of 0.32, specificity of 0.78, PPV of 0.37, and NPV of 0.75. Accuracy for prediction of perioperative hard and soft cardiac events was a sensitivity of 0.20 and 0, specificity of 0.99 and 0.99, PPV of 0.33 and 0, and NPV of 0.98 and 0.89, respectively. For long term hard and soft cardiac events, sensitivity was 0.5 and 0, specificity 0.99 and 0.98, PPV 0.33 and 0, and NPV 0.99 and 0.96, respectively. DSE has a limited accuracy for the detection of CAD in candidates for OLT. However, among those patients selected for OLT, the negative predictive value of DSE for both perioperative and long term cardiac events is high.

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Usefulness of Dobutamine Stress Echocardiography with Tissue Doppler Imaging for the Evaluation and Follow-Up of Patients with Repaired Tetralogy of Fallot

The longstanding pulmonary regurgitation in patients with repaired tetralogy of Fallot (RTOF) results in right ventricular (RV) failure. The estimation of RV function and reserve in these patients is of great importance, especially for the determination of the proper timing of pulmonary valve replacement. Tissue Doppler imaging (TDI) of the tricuspid annulus has been proved a valuable tool in the evaluation of these patients. Dobutamine stress echocardiography (DSE) in low doses detects the contractility reserve of cardiac myocytes. The aim of our study was to estimate RV reserve in patients with RTOF with the use of DSE and TDI and to examine whether this is related to baseline TDI indices of the tricuspid annulus. We studied 21 patients with RTOF and 21 age- and gender-matched controls with TDI Doppler at the tricuspid annulus during DSE. TDI measurements were made at baseline and at infusion rates of 10 and 20 microg x kg x min. Patients with RTOF had lower values of TDI indices at baseline and during dobutamine infusion and smaller dobutamine-induced increase of Sa (DeltaSa) (3.8 +/- 1.2 vs. 10.8 +/- 3.6 cm/sec, P < .001) and Aa (3.5 +/- 2.2 vs. 10.0 +/- 3.2 cm/sec, P < .001). A value of DeltaSa < or = 6 cm/sec clearly discriminated patients from controls and could be predicted by values of Sa < 11.5 cm/sec with sensitivity of 95% and specificity of 100%. In patients with RTOF, impaired RV contractile reserve can be documented with TDI of tricuspid annular motion during DSE and is predicted by TDI indices at rest. Its serial estimation may contribute to optimal timing of reoperation.

Dobutamine Stress Echocardiography in the Assessment of Cardiac Allograft Vasculopathy in Asymptomatic Recipients

Purpose Cardiac allograft vasculopathy (CAV) is the most important cause of late mortality among cardiac allograft recipients. Dobutamine stress echocardiography (DSE) is considered a safe and cost-effective method to screen these patients who remain free of angina most of the time. We evaluated DSE results in a series of cardiac allograft recipients. Methods The DSE was performed on a yearly basis. From 2004 to 2006, twelve DSEs were performed on 8 patients, including 7 men, and overall mean age of 36 ± 12 years. Dobutamine infusion begun at 5 μg/kg/min was titrated at 3-minute stages to 10, 20, 40, and 50 μg/kg/min to achieve the target heart rate. In addition, at every stage, we performed a 12-lead EKG, heart rate, and blood pressure recording. The DSE results were compared with coronary angiograms and endomyocardial biopsies. Results Two patients displayed mildly and 1 patient a severely abnormal DSE test. The severely abnormal DSE test was associated with severe coronary artery stenosis, including inexperiment of the left main coronary artery. The second patient with an abnormal DSE had contour irregularities and distal cut-off of the right coronary artery as well as 2R cellular rejection. The third patient had a normal angiogram and no rejection. None of the patients with normal DSE experienced a cardiac event, coronary lesions, or rejection. Conclusion Use of DSE appears to be a sensitive method to detect CAV in asymptomatic recipients. However, mild wall motion abnormalities can be detected in patients without stenosing coronary lesions. The value of DSE in predicting CAV must be examined in larger series with long-terms of follow-up.

Head to head comparison of transesophageal and transthoracic contrast-enhanced echocardiography during dobutamine administration for the detection of coronary artery disease

Dobutamine stress echocardiography (DSE) has been shown to be a very useful non-invasive technique for the detection of coronary artery disease. However, inadequate transthoracic images preclude the use of DSE in a significant proportion of patients. Transesophageal (TEE) or transthoracic contrast echocardiography (CE) can however overcome this limitation. The comparison between the two techniques has never been investigated during a stress test. Therefore, we designed a prospective study to compare DSE-CE and DSE-TEE for the detection of coronary artery disease in patients with poor echo image quality. We studied 42 patients scheduled for quantitative coronary angiography. Prospective DSE-CE and DSE-TEE with maximum one day interval were performed in a random order. Significant coronary artery disease was detected in 30 patients, nine with single vessel disease and 21 with multivessel disease. Sensitivity of DSE was higher with CE than with TEE (90% vs 87%, p = NS). There was no significant difference with respect to specificity in both groups (100% vs 92%, p = NS). The diagnostic accuracy was similar in both groups (93% vs 88%, NS). The κ value for identical interpretation of a stress echocardiography study was nearly identical with both modalities 0.75 to 0.78. In poorly echogenic patients, DSE-CE is a valuable alternative for the detection of myocardial ischemia in comparison with DSE-TEE. Because DSE-CE is more comfortable than TEE, it should be used in patients with suboptimal transthoracic echocardiograms for the evaluation of coronary artery disease during DSE.

Letter by Schinkel et al Regarding Article, “Projected Valve Area at Normal Flow Rate Improves the Assessment of Stenosis Severity in Patients With Low-Flow, Low-Gradient Aortic Stenosis: The Multicenter TOPAS (Truly or Pseudo-Severe Aortic Stenosis) Study”

To the Editor: In a recent study by Blais and colleagues,1 the authors reported the use of dobutamine stress echocardiography (DSE) in patients with low-output, low-gradient aortic valve stenosis. Clinical decision making regarding these patients is challenging, and the clinical advantage of DSE is in distinguishing truly and pseudosevere aortic stenosis and evaluating contractile reserve.2–4 The authors have not made specific recommendations about the safety of DSE in these patients, but they have stated that “in a significant proportion of …

Comparison of real-time tri-plane and conventional 2D dobutamine stress echocardiography for the assessment of coronary artery disease

Although dobutamine stress echocardiography (DSE) is an accepted tool for the diagnosis of coronary artery disease (CAD), it requires subsequent image acquisitions of the left ventricle (LV) in order to visualize all segments. This makes the procedure relatively time-consuming and might limit its accuracy. With the introduction of matrix array transducers, the real-time simultaneous acquisition of all LV segments has become possible using multi-plane imaging. The purpose of this study was: (i) to test the feasibility and efficiency of real-time tri-plane (RT3P) imaging during DSE, (ii) to compare the accuracy of RT3P DSE in detecting CAD using coronary angiography as the reference method. Thirty-six patients suspected of CAD were prospectively enrolled. Both conventional two-dimensional (2D) and RT3P imaging were performed during a DSE protocol. Coronary angiography was performed within 24 h. Ultrasound data were acquired at each stage of the DSE. The total effective acquisition time for RT3P imaging was significantly shorter (55+/-29 vs. 137+/-63 s, P<0.001). Data yield was similar for both methods (2D: 98% vs. 3D: 97%). Overall sensitivity (93%), specificity (75%), and accuracy (89%) were identical between both methods. On a segmental level, the sensitivity, specificity, and accuracy of the RT3P and the 2D DSE were similar. RT3P imaging fastens the DSE protocol without compromising the accuracy for the diagnosis of CAD. This could facilitate a more wide-spread use of DSE and therefore contributes positively to its routine clinical acceptance.

Enoximone echocardiography: a novel test to evaluate left ventricular contractile reserve in patients with heart failure on chronic beta-blocker therapy.

BackgroundIt has been suggested that an extensive contractile reserve identified recognised by means of dobutamine stress echocardiography may predict a better prognosis in patients with severe left ventricular dysfunction at rest. However, the clinical use of dobutamine stress echocardiography may be limited in patients with chronic heart failure by the substantial proportion of such patients treated with beta-blockers, since the inotropic response to adrenergic stimulation is known to be attenuated in patients receiving beta-adrenoceptor blockers. Enoximone is a positive inotropic agent that inhibits cyclic adenosine monophosphate-specific phosphosdiesterase. We therefore tested the hypothesis that enoximone may be an alternative to dobutamine in evaluating left ventricular contractile reserve in patients with systolic dysfunction on chronic beta-blocker therapy.MethodsWe studied 26 patients (21 males and five females) with a mean age of 58 ± 10 years: 11 were not receiving beta-blockers (noBB group); 15 were receiving carvedilol at a mean dose of 34 mg/day (BB group). Dobutamine was infused at doses of 5 and 10 micrograms/kg/min, and enoximone at a dose of 1.5 mg/kg.ResultsThe ejection fraction in the noBB group increased by 9% with dobutamine and 8.73% with enoximone (p = 0.86); in the BB group, it increased by 6% with dobutamine and 8.94% with enoximone (p = 0.03). Regional peak systolic velocities were evaluated by means of tissue Doppler imaging in four basal and four medium level segments. In the noBB group, they increased more with dobutamine than with enoximone in three of the eight segments; no significant differences were found in the BB group. Dobutamine induced non-sustained ventricular tachycardia in three patients and supraventricular tachycardia in one, whereas enoximone did not induce any repetitive arrhythmias.ConclusionsEnoximone might be preferable to low-dose dobutamine for evaluating left ventricular contractile reserve in chronically beta-blocked heart failure patients as it is slightly more potent and has a better safety profile.

The correlation between expression of apoptosis-related proteins and myocardial functional reserve evaluated by dobutamine stress echocardiography in patients with dilated cardiomyopathy

The relation between myocardial functional changes and the apoptosis-related proteins in patients with dilated cardiomyopathy (DCM) has not yet been reported. The purpose of this study was to assess this issue through the use of dobutamine stress echocardiography. A total of 81 segments of left ventricles (from 6 patients with DCM) were collected in this study. Segments from another 5 patients who had died of noncardiac causes were used as the control. Apoptosis-related proteins (bax, bcl-2, and p53) and apoptosis were evaluated in these segments by immunocytochemical stain and terminal deoxynucleotidyl transferase-mediated DNA nick end-labeling assay. There were 26 segments with dobutamine-induced contractile reserve. There were significant differences in numbers of segments with overexpression of bcl-2 and bax in the study and control groups. However, p53 was not found in either group. The total terminal deoxynucleotidyl transferase-mediated DNA nick end-labeling–positive nuclei in explanted hearts of DCM was 0.73%. The myocardial contractile reserve was inversely associated with an overexpression of bcl-2 ( P < .01) rather than bax. In conclusion, the expression of bax and bcl-2 proteins in patients with DCM is enhanced and independent of p53. Loss of contractile reserve is associated with overexpression of bcl-2 protein in failing myocardium.

Dobutamine stress echocardiography predicts myocardial improvement in patients supported by left ventricular assist devices (LVADs): hemodynamic and histologic evidence of improvement before LVAD explantation

Background: Cardiac function may improve in patients with end-stage heart failure who receive long-term support (>30 days) with left ventricular assist devices (LVADs). Dobutamine stress echocardiography (DSE) has been used to quantitate myocardial recovery in patients with heart failure supported with LVADs. By recording the hemodynamic response with the use of DSE, we evaluated and applied the resulting data to patients receiving LVAD support. Methods and results: The study population included 16 patients who underwent LVAD implantation, regained functional capacity on full LVAD support, and tolerated decreased mechanical support with no worsening of dyspnea or fatigue. All 16 patients underwent dobutamine stress with increasing doses of dobutamine (from 5 to 40 mcg/kg/min). Hemodynamics and 2-dimensional (2-D) echocardiography was performed at each dose level. In addition, paired myocardial samples were obtained and analyzed histologically to determine myocyte size and collagen content. Dobutamine stress separated the study population into 2 groups: those who had favorable responses to dobutamine (9/16) and those who had unfavorable responses (i.e., experienced hemodynamic deterioration; 7/16). Favorable dobutamine responses were characterized by improved cardiac index, improved force-frequency relationship in the left ventricle (dP/dt), improved left ventricular ejection fraction, and decreased left ventricular end-diastolic dimension. All 9 favorable responders underwent LVAD explantation, and 6 survived for more than 12 months. In all patients studied, LVAD support resulted in decreased myocyte size ( n = 14, 33.9 ± 0.9 μm before vs 16.6 ± 0.8 μm after support, p = 0.0001; normal, 5–15 μm) but resulted in no consistent changes in collagen content. Conclusions: Dobutamine stress echocardiography with hemodynamic assessment may be a useful tool in assessing physiologic improvement in myocardial function of patients with end-stage heart failure who receive LVAD support. It may help predict which patients can tolerate LVAD removal. Prospective analysis of cardiac function is now warranted to better define myocardial recovery in patients supported with LVADs.

Long-Term Follow-Up and Dobutamine Stress Echocardiography of 19-mm Prosthetic Heart Valves.

BACKGROUND: In patients with a small aortic root, the use of 19-mm valve prostheses for valve replacement is controversial because of the small orifice area of these valves. METHODS: To assess stress hemodynamics in patients with 19-mm valve prostheses, to find predictors of unfavorable hemodynamics, and to document the long-term follow-up, we examined 30 patients (age, 64 +/- 19 years; 27 women and 3 men; follow-up, 38 +/- 50 months) clinically and with the use of dobutamine stress echocardiography. A history was taken, and a physical examination was performed. At rest and during dobutamine stress, Doppler echocardiography was performed. RESULTS: At rest, transprosthetic gradients were moderately elevated with mean and peak gradients of 15 +/- 7 and 32 +/- 14 mmHg, and effective orifice areas were small (0.91 +/- 0.31 cm(2)). Gradients rose markedly during stress (mean, 37 +/- 14 mmHg; peak, 83 +/- 41 mmHg). Predictors of high transprosthetic gradients were larger body surface area, younger age, and valve type. Mean and peak gradients were lower with St. Jude Medical Hemodynamic Plus valves than with standard St. Jude Medical (P < 0.05) and other valves, and the effective orifice area was highest (1.07 +/- 0.29 cm(2); P < 0.05 versus standard St. Jude Medical) in this valve model. Sixty percent of patients developed significant dynamic subvalvular or intraventricular gradients (84 +/- 41 mmHg) during dobutamine stress. CONCLUSIONS: After aortic valve replacement with 19-mm prostheses in patients with a small aortic root, dobutamine stress leads to high transvalvular gradients, which are dependent on valve model, age, and body surface area. In addition, 60% of patients develop significant dynamic outflow obstructions. These findings and the persistence of some degree of exercise-induced symptoms in 70% of patients suggest that alternative surgical techniques should be considered if the size of the aortic annulus demands a 19-mm valve, especially if the patient seeks physical activity, is young, or is of larger body size.