Qualitative Myocardial Contrast Echocardiography Research Articles

Resting qualitative and quantitative myocardial contrast echocardiography to predict cardiac events in patients with acute myocardial infarction and percutaneous revascularization

Successful restoration of patency of the infarct-related artery is important in management of acute ST-segment elevation myocardial infarction (STEMI); however, it does not necessarily translate into the restoration of perfusion at the tissue level. In this study, we evaluate the prognostic role of qualitative and quantitative myocardial contrast echocardiography (MCE) in predicting cardiac events (after adjustment for cardiovascular risk factors) in STEMI patients undergoing reperfusion. Bedside resting real-time MCE using continuous infusion of diluted contrast agent (Definity) was performed within a median of 21.4 h from revascularization in STEMI. Myocardial perfusion on qualitative MCE was graded 1 = homogenous; 2 = partial/patchy; and 3 = absent. Perfusion score index (PSI) was calculated by adding the perfusion score in all segments divided by the total number of evaluable segments. Quantitative perfusion parameters [A, dB; β, sec(-1); and Aβ] were analyzed using a 17-segment model. Patients were followed for cardiac events including death; nonfatal myocardial infarction (MI); hospitalization for cardiac symptoms; coronary revascularization; or heart failure. Thirty-seven reperfused STEMI patients with a mean age of 64 years (range, 40-86 years) were enrolled and followed for a median of 1.4 years. Cardiac events occurred in 22 patients. Patients with cardiac events had a higher perfusion score index (PSI), and lower A, β and Aβ parameters compared to patients without events [1.84 ± 0.36 vs 1.39 ± 0.17 for PSI, P < 0.001; 0.57 ± 0.24 vs 0.85 ± 0.30 for A, P = 0.03; 0.34 ± 0.15 vs. 0.53 ± 0.17 for β, P = 0.002; and 0.21 ± 0.12 vs. 0.49 ± 0.32, for Aβ, P = 0.003; respectively]. A PSI value of 1.58 provided an area under the curve (AUC) of 0.873, while β of 0.423 and Aβ of 0.323 provided an AUC of 0.858 and 0.842, respectively. PSI and Aβ were independent predictors of cardiac events with an adjusted hazard ratio of 3.41 (1.19-12.27); and 4.19 (1.3-19.09), respectively. No contrast-related side effects were reported. Evaluation of perfusion in reperfused STEMI patients by qualitative and quantitative MCE (myocardial blood flow, Aβ) provides independent prediction of cardiac events.

Myocardial Contrast Echocardiography Versus Single Photon Emission Computed Tomography for Assessment of Hibernating Myocardium in Ischemic Cardiomyopathy: Preliminary Qualitative and Quantitative Results

Single photon-emission computed tomography (SPECT) is widely used for the assessment of hibernating myocardium (HM). The aim of this study was to test the hypothesis that myocardial contrast echocardiography (MCE), because of its better spatial and temporal resolution, would be superior to SPECT for the detection of HM. Thirty-nine consecutive patients with symptomatic ischemic cardiomyopathy underwent rest and vasodilator SPECT and MCE. Of these, 23 survived to undergo assessment 3 months after revascularization for the recovery of left ventricular (LV) function (spontaneous recovery or dobutamine induced), which is the definition of HM. Of the 214 dysfunctional segments, 156 segments demonstrated HM in the 23 patients, of whom 16 showed significant improvement in LV function. Logistic regression analysis showed that both qualitative and quantitative MCE were independent predictors for the detection of HM (P < .0001 vs P = .06 for qualitative MCE vs qualitative SPECT, respectively, and P < .01 vs P = .25 for all quantitative myocardial contrast echocardiographic parameters vs quantitative SPECT, respectively). Using clinical and LV functional data, SPECT, and MCE for predicting the recovery of LV function, MCE was the only independent predictor (P = .03). MCE was superior to SPECT for the assessment of HM in ischemic cardiomyopathy.

Diagnostic accuracy of contrast echocardiography during adenosine stress for detection of abnormal myocardial perfusion: a prospective comparison with technetium-99 m sestamibi single-photon emission computed tomography

Myocardial contrast echocardiography (MCE) utilizes compressible microbubbles behaving similarly to red blood cells. Destruction of microbubbles and observation of the gradual refill into the myocardium are key to evaluating perfusion using real-time MCE. We aimed to assess the feasibility and diagnostic accuracy of qualitative MCE utilizing a 17-segment model for localization of myocardial perfusion abnormalities compared with simultaneous technetium-99 m sestamibi single-photon emission computed tomography (SPECT). From July 2005 through August 2007, 97 patients with known or suspected coronary artery disease underwent simultaneous SPECT and realtime MCE during adenosine stress. Qualitative MCE and tracer uptake were analyzed visually using a 17-segment model in a blinded manner. Diagnostic accuracy and 95% confidence interval (CI) were determined. Myocardial contrast echocardiography was completed in 91 patients (age, mean [SD], 69.3 [10.9] years; body mass index, 30.0 [6.3]; 59 males [65%]). Myocardial contrast echocardiography analysis was feasible in 88 (97%) patients (261 of 264 [99%] territories; 1299 of 1497 [87%] segments). At patient level, MCE sensitivity was 88% (95% CI, 79%-94%); specificity was 85% (77%-90%). For disease detection in individual coronary territories, sensitivity and specificity were 84% (71%-92%) and 79% (72%-84%) for the left anterior descending artery; 62% (38%-80%) and 88% (83%-91%) for the left circumflex artery; and 73% (57%-82%) and 94% (89%-97%) for the right coronary artery. For MCE combined with wall-motion analysis, concordance with SPECT improved from 80% to 86%. Myocardial contrast echocardiography interobserver concordance was 81% (kappa [SE], 0.611 [0.78]). Myocardial contrast echocardiography accuracy was comparable in patients classified in accordance with presence of diabetes mellitus, myocardial infarction, hypertension, or percutaneous coronary intervention. Improved MCE specificity in detecting perfusion defects was seen in patients with no history of coronary bypass graft surgery (P = 0.005). Real-time MCE with a 17-segment model for analysis has good feasibility and accuracy in evaluation of myocardial perfusion during adenosine stress.

Microvascular Function in Takotsubo Cardiomyopathy With Contrast Echocardiography: Prospective Evaluation and Review of Literature

Takotsubo cardiomyopathy (TC) mimics ST-elevation myocardial infarction without substantial angiographic stenosis. Coronary microvascular dysfunction has been proposed as a possible mechanism in TC. The aim of this study was to evaluate microvascular function in TC using real-time myocardial contrast echocardiography (MCE). Real-time MCE was performed within 24 hours of coronary angiographic diagnosis of TC. Myocardial perfusion was evaluated through qualitative and quantitative myocardial contrast echocardiographic analyses comparing normal segments with segments with dysfunctional wall motion (WM). From January 2007 to January 2008, 11 patients received diagnoses of TC. Of these patients, 9 were prospectively enrolled (mean age, 70.9 +/- 17.5 years; 8 women). Qualitative and quantitative myocardial contrast echocardiographic analyses were feasible in 87% and 81% of segments. Overall, concordance between qualitative MCE and WM for normal versus abnormal analysis was observed in 71% of segments (kappa = 0.442, SE = 0.08). Significantly lower myocardial blood flow velocity (beta) and lower myocardial blood flow (Abeta) were detected in segments with dysfunctional WM compared with those with normal WM (beta = 0.55 +/- 0.39 vs 0.90 +/- 0.77, P = .009; Abeta = 5.31 +/- 3.92 vs 12.38 +/- 13.47, P = .002). In the discordant segments between qualitative MCE and WM, the quantitative perfusion parameters beta and Abeta were significantly lower in segments with dysfunctional WM compared with those with normal WM (beta = 0.22 +/- 0.20 vs 1.79 +/- 0.57, P = .01; Abeta = 1.90 +/- 1.1 vs 24.29 +/- 19.9, P = .02). Recovery of WM abnormalities was detected in all patients during follow-up echocardiography (mean, 60.3 +/- 66.0 days). No contrast-related side effects were reported. During mean follow-up of 5.9 +/- 4.6 months, there were no cardiac events, but 1 noncardiac death (from lung cancer) occurred. TC is associated with abnormal myocardial perfusion detected with qualitative and quantitative MCE, indicative of microvascular dysfunction.

Accelerated Stress Real-Time Myocardial Contrast Echocardiography for the Detection of Coronary Artery Disease: Comparison with 99mTc Single Photon Emission Computed Tomography

The aims of this prospective study were to compare the diagnostic value of accelerated vasodilator stress real-time myocardial contrast echocardiography (MCE) and single photon emission computed tomography (SPECT) against coronary angiography and to evaluate whether the addition of MCE perfusion data improves the diagnostic accuracy of stress echocardiography. A total of 103 patients with suspected or known stable coronary artery disease (CAD) underwent SPECT and accelerated high-dose dipyridamole (0.84 mg/kg intravenously for 4 minutes) atropine (up to 1 mg intravenously) stress real-time qualitative MCE. The presence of CAD was detected by coronary angiography. CAD defined as >or= 70% stenosis was detected in 77% of patients, whereas 86% of patients had CAD defined as >or= 50% stenosis. In a territory-by-territory analysis, the concordance between MCE and SPECT in detecting perfusion defects varied from 72.8% (kappa = 0.386) to 89.3% (kappa = 0.642). There were no significant differences between MCE and SPECT in sensitivity, specificity, and diagnostic accuracy for identifying patients with CAD. Combining MCE and wall motion abnormality analysis significantly improved the sensitivity of the test compared with wall motion abnormality analysis alone. Accelerated vasodilator stress real-time MCE yields a good concordance with SPECT in detection of perfusion defects and a similar diagnostic value for the detection of CAD. The addition of MCE perfusion data improves the diagnostic value of stress echocardiography.

Myocardial contrast echocardiography in biopsy-proven primary cardiac amyloidosis

Cardiac vasculature is affected in 88-90% of patients with primary cardiac amyloidosis (CA). Myocardial contrast echocardiography (MCE) relies on the ultrasound detection of microbubble contrast agents that are solely confined to the intravascular space, and are therefore useful in the evaluation of flow in the microvasculature. This is the first case report describing the use of MCE during vasodilator stress to evaluate coronary flow reserve in a patient with biopsy-proven primary CA and angiographically normal coronaries. Qualitative MCE demonstrated delayed replenishment of microbubbles during peak stress; quantitative analysis was consistent with a reduction in total myocardial blood flow and reserve values. Comparative imaging modalities including strain and strain rate imaging, magnetic resonance imaging, and myocardial scintigraphy were suggestive to the diagnosis of CA. In conclusion, MCE is a method for recognition of microvascular dysfunction, and might be considered as a useful tool to augment echocardiographic assessment in the early diagnosis of CA.

Comparison of Specificity of Quantitative Myocardial Contrast Echocardiography for Diagnosis of Coronary Artery Disease in Patients With Versus Without Diabetes Mellitus

Impaired coronary flow reserve is widely reported in diabetes mellitus (DM) but its effect on myocardial contrast echocardiography (MCE) is unclear. We sought to identify whether DM influences the accuracy of qualitative and quantitative assessment of coronary artery disease (CAD) using MCE in 83 patients who underwent coronary angiography (60 men, 27 with DM; 56 +/- 11 years;). Destruction replenishment imaging was performed at rest and after combined dipyridamole-exercise stress testing. Ischemia was identified by the development of new wall motion abnormalities, qualitative MCE (new perfusion defects apparent 1 second after flash during hyperemia), and quantitative MCE (myocardial blood flow reserve <2.0 in the anterior circulation). Qualitative and quantitative assessment of perfusion was feasible in 100% and 92% of patients, respectively. Significant left anterior descending coronary stenosis (>50% by quantitative angiography) was present in 28 patients (including 8 with DM); 55 patients had no CAD (including 19 with DM). The myocardial blood flow reserve was reduced in patients with coronary stenosis compared with those with no CAD (1.6 +/- 1.1 vs 3.8 +/- 2.5, p <0.001). Among patients with no CAD, those with DM had an impaired flow reserve compared with control patients without DM (2.4 +/- 1.0 vs 4.5 +/- 2.8, p = 0.003). In conclusion, DM significantly influenced the quantitative, but not the qualitative, assessment of MCE, with a marked reduction in specificity in patients with DM.

Identification of Stunned Myocardium With Parametric Imaging-Based, Quantitative Myocardial Contrast Echocardiography After Acute Myocardial Infarction

Microvascular integrity demonstrated by myocardial contrast echocardiography (MCE) predicts functional recovery after an acute myocardial infarction (AMI). Recently, parametric imaging-based quantitative MCE has been developed. Our aim was to assess the usefulness of parametric imaging-based quantitative MCE parameters to predict the functional recovery of akinetic segments after primary percutaneous transluminal coronary angioplasty (PTCA). Fifty-three consecutive patients with a first AMI were enrolled. They underwent primary PTCA. Standard echocardiography and real-time MCE were performed. Qualitative analysis and parametric imaging-based quantitative parameters were measured offline by different blinded investigators. Dobutamine stress echocardiography was performed 1 month later. A new standard echocardiogram to assess the functional status of the akinetic segments and coronary angiography to evaluate the presence of restenosis at the level of the culprit lesion were performed 6 months later. The mean patient age was 62.9 +/- 14 years, and 42 were men (79%); 170 segments were akinetic. Of these, 105 (62%) recovered their function. The best parameter to predict functional recovery was the myocardial blood flow velocity (beta). These results were better than those obtained using dobutamine stress echocardiography and qualitative MCE to predict functional recovery. In conclusion, parametric imaging-based quantitative MCE is an accurate diagnostic tool to detect stunned myocardium after AMI. Its diagnostic accuracy in predicting the functional recovery of akinetic segments after primary PTCA is better than the accuracy of dobutamine stress echocardiography and qualitative MCE.

Myocardial contrast echocardiography accurately reflects transmurality of myocardial necrosis and predicts contractile reserve after acute myocardial infarction

Both myocardial contrast echocardiography (MCE) and cardiovascular magnetic resonance (CMR) can identify myocardial necrosis after acute myocardial infarction (AMI). However, transmural extent of infarction (TEI) correlates of myocardial perfusion by MCE after AMI are unknown. We sought to ascertain the ability of MCE to (1) predict TEI as defined by contrast-enhanced CMR and (2) to compare the relative accuracy of these techniques to predict contractile reserve late after AMI. MCE and CMR were performed in 42 patients with AMI 7 to 10 days after thrombolysis. Contractile reserve with low-dose dobutamine was evaluated 12 weeks after revascularization. Both qualitative (myocardial contrast intensity) and quantitative MCE [peak contrast intensity, microbubble velocity (beta), and myocardial blood flow] showed a significant (P < .0001) inverse relationship with increasing TEI. However, beta was the single best predictor of TEI (P = .002). Both qualitative MCE and CMR predicted contractile reserve similarly (area under receiver operating characteristic curve were 0.84 and 0.80, respectively). Qualitative and quantitative MCE parameters as well as CMR correlated significantly with the degree of contractile reserve (P < .001). Multiple logistic regression analysis using clinical, electrocardiographic, MCE, and CMR parameters showed that both MCE (OR = 0.03, 95% CI 0.01-0.10, P < .001) and CMR (OR = 0.11, 95% CI 0.04-0.26, P < .001) are independent predictors of contractile reserve. The most discriminative quantitative parameters for prediction of contractile reserve were microbubble velocity (P < .001) and myocardial blood flow (P = .001) assessed by MCE. MCE reflects the transmural extent of AMI as assessed by CMR. Both techniques predict contractile reserve.

Quantitative myocardial contrast echocardiography for prediction of Thrombolysis In Myocardial Infarction flow in acute myocardial infarction

Clinical evaluation of arterial patency in acute ST-elevation myocardial infarction (STEMI) is unreliable. We sought to identify infarction and predict infarct-related artery patency measured by the Thrombolysis In Myocardial Infarction (TIMI) score with qualitative and quantitative intravenous myocardial contrast echocardiography (MCE). Thirty-four patients with suspected STEMI underwent MCE before emergency angiography and planned angioplasty. MCE was performed with harmonic imaging and variable triggering intervals during intravenous administration of Optison. Myocardial perfusion was quantified offline, fitting an exponential function to contrast intensity at various pulsing intervals. Plateau myocardial contrast intensity (A), rate of rise (β), and myocardial flow (Q = A × β) were assessed in 6 segments. Qualitative assessment of perfusion defects was sensitive for the diagnosis of infarction (sensitivity 93%) and did not differ between anterior and inferior infarctions. However, qualitative assessment had only moderate specificity (50%), and perfusion defects were unrelated to TIMI flow. In patients with STEMI, quantitatively derived myocardial blood flow Q (A × β) was significantly lower in territories subtended by an artery with impaired (TIMI 0 to 2) flow than those territories supplied by a reperfused artery with TIMI 3 flow (10.2 ± 9.1 vs 44.3 ± 50.4, p = 0.03). Quantitative flow was also lower in segments with impaired flow in the subtending artery compared with “normal” patients with TIMI 3 flow (42.8 ± 36.6, p = 0.006) and all segments with TIMI 3 flow (35.3 ± 32.9, p = 0.018). An receiver-operator characteristic curve derived cut-off Q value of <11.3, representing impaired myocardial flow, was 73% sensitive and 67% specific for TIMI <3 flow at angiography. Thus, qualitative MCE identifies patients with STEMI but provides no information regarding infarct-related artery patency, whereas quantitative MCE can predict impaired flow in patients with acute STEMI.