Usefulness of myocardial contrast echocardiography in predicting collateral blood flow in the presence of a persistently occluded acute myocardial infarction-related coronary artery

Rupture of Aortic Sinus Aneurysms Diagnosed by Left Ventricular Opacification

Rupture of aortic sinus aneurysms is a rare cardiac malformation that is commonly observed in the right coronary sinus but is rarely observed in the noncoronary sinus. Here, we report a case of aneurysm of the aortic sinus that ruptured into the left ventricular outflow tract and was diagnosed with left ventricular opacification. Left heart echocardiography can clearly demonstrate the structure of the heart and is one of the important diagnostic methods for diagnosing ruptured aortic sinus aneurysms. This observes the perfusion sequence of blood flow to clearly reveal the source, direction, and location of the ruptured aortic sinus aneurysm.

Myocardial contrast echocardiography for the detection of coronary artery disease in patients with global hypokinesis admitted for first-onset acute heart failure: pilot study

Background

The non-invasive differentiation of ischemic and nonischemic acute heart failure (AHF) not resulting from acute myocardial infarction is difficult and has therapeutic and prognostic implications. The aim of this study was to assess whether resting myocardial contrast echocardiography (MCE) can detect coronary artery disease (CAD) in patients with decreased left ventricular (LV) systolic function and global hypokinesis presenting with AHF.

Methods

Twenty-one consecutive patients underwent low-power real-time MCE based on color-coded pulse inversion Doppler. Standard apical LV views were acquired during contrast IV infusion of Definity®. Following transient microbubbles destruction, the contrast replenishment rate (β), reflecting myocardial blood flow velocity, was derived by plotting signal intensity vs. time and fitting data to the exponential function: y (t) = A (1 - e^-β(t-t0)) + C.

Results

Of the 21 (mean age 56.6 ± 13.6 years) patients, 5 (23.8%) demonstrated flow-limiting CAD (> 70% of luminal diameter narrowing). The mean ± standard deviation of LV ejection fraction was 29.6 ± 8.6%. Quantitative MCE analysis was feasible in 258 of 378 segments (68.3%). There were no significant difference in "β" and "Aβ" in patients without and with CAD (0.48 ± 0.27 vs. 0.45 ± 0.25, p = 0.453 for β and 2.99 ± 2.23 vs. 3.68 ± 3.13, p = 0.059 for Aβ, respectively). No contrast-related side effects were reported.

Conclusion

Resting quantitative MCE analysis in patients with AHF was feasible, however, the parameters did not aid in detecting of CAD.

Comparison between myocardial contrast echocardiography and (99m)technetium sestamibi single photon emission computed tomography determined myocardial viability in predicting hard cardiac events following acute myocardial infarction

The extent of residual myocardial viability (MV) after acute myocardial infarction (AMI) is an important determinant of the outcome. Single photon emission computed tomography (SPECT) is widely used to assess MV after an AMI. However, myocardial contrast echocardiography (MCE), a relatively new technique for the assessment of MV, has better spatial and temporal resolution than SPECT. The present study evaluated whether MV determined by MCE is comparable to that determined using SPECT for the prediction of hard cardiac events after an AMI. Accordingly, 99 patients who had undergone simultaneous rest low-power MCE and nitrate-enhanced SPECT 7 days after an AMI were followed up for cardiac death and AMIs. Both MCE perfusion (1 = normal; 2 = reduced; and 3 = absent) and SPECT tracer uptake (0 = normal; 1 = mildly reduced; 2 = moderately reduced; 3 = severely reduced; and 4 = absent) were scored on a 16-segment left ventricular model. The contrast perfusion index and SPECT perfusion index were calculated by adding the respective scores in the 16 segments and dividing by 16. The contrast perfusion index and SPECT perfusion index were used as a measure of the residual MV on MCE and SPECT, respectively. Of the 99 patients recruited, 95 were available for the follow-up examination (follow-up 46 +/- 16 months). A total of 15 events (16%) occurred (8 cardiac deaths and 7 AMIs). Of the clinical, biochemical, echocardiographic, and SPECT markers of prognosis, the only independent predictors of cardiac death and cardiac death or AMI were age and MV as determined by MCE (p = 0.01 and p = 0.002, respectively). In conclusion, MV determined by MCE at rest was superior to nitrate-enhanced SPECT for the prediction of hard cardiac events after AMI.

Relationship between collateral circulation and successful myocardial reperfusion in acute myocardial infarction: a subanalysis of the PREMIAR trial

The aim of this study was to determine whether the presence of collateral circulation had a beneficial effect following primary angioplasty. In all, 114 patients who underwent primary angioplasty were included. Patients with collateral circulation had lower basal ST-segment deviation (P = .004), white cell count ( P = .001), peak creatine kinase (P = .001), and regional wall motion score values (P = .03) than patients without collateral circulation. After the procedure, the group with collaterals was associated with higher rates of normal myocardial blush, complete ST resolution, and shorter time to stable ST-recovery. Multivariable logistic analysis identified the presence of collateral circulation as independent predictor of normal myocardial blush (adjusted odds ratio = 3.98, 95% confidence interval, 1.12-14.09; P = .033) and rapid reperfusion (time to stable ST-segment recovery <7 minutes, adjusted odds ratio = 4.0, 95% confidence interval, 1.57-10.20; P = .004). The presence of collateral circulation has a protective effect on infarct size, resulting in faster reperfusion.

Effect of systemic blood pressure on microcollateral circulation evaluated by real-time contrast echocardiography

BACKGROUND

In acute myocardial infarction, residual collateral-derived myocardial blood flow (CBF) within the ischemic area is one of the major determinants of infarct size. Management of systemic blood pressure (sBP) related to maintain collateral circulation is still difficult. The aim of this study was to reveal the influence of sBP on the rescue of area at risk by collateral circulation.

METHODS

Real-time myocardial contrast echocardiography just after the onset of complete occlusion of the left circumflex coronary artery was performed in collateral-rich open-chest dogs. The video intensity of the ischemic area was evaluated during the occlusion and the CBF (A x beta) was calculated from a replenishment curve: y = A (1 - e(-beta t)). To analyze the effect of sBP on the collateral circulation, sBP was altered by infusion of nitroglycerin or etilefrine hydrochloride. To evaluate the defect size (%DS), every end-systolic myocardial contrast echocardiography image after left circumflex coronary artery occlusion was converted into binary images using custom offline software.

RESULTS

The %DS increased and CBF slightly decreased at low sBP. The %DS decreased and CBF increased at high sBP. At excessively high sBP, %DS increased and CBF decreased again.

CONCLUSION

Real-time myocardial contrast echocardiography, which is a useful noninvasive method to evaluate the collateral perfusion quantitatively, has a crucial role in the decision of patient treatment and management strategy of acute myocardial infarction.

Contrast echocardiography accurately predicts myocardial perfusion before angiography during acute myocardial infarction

OBJECTIVES

To determine whether myocardial contrast echocardiography (MCE) can quickly and accurately assess myocardial perfusion and infarct-related artery (IRA) patency before emergency angiography during acute myocardial infarction (AMI).

BACKGROUND

Despite encouraging experimental and clinical studies, the reliability and practicality of MCE in predicting IRA patency during AMI before angiography has not been proven.

METHODS

Two-dimensional echocardiography and MCE were performed in 51 patients with AMI just before emergency angiography. With knowledge of the electrocardiogram findings and regional wall motion, myocardial perfusion was assessed to predict IRA patency.

RESULTS

Myocardial perfusion studies were adequate for interpretation in 40 patients. An occluded IRA was predicted in 28 patients; the artery was occluded in 22 patients, and six patients had Thrombolysis In Myocardial Infarction (TIMI) grade 2 flow or less. A patent IRA was predicted in 12 patients; eight patients had TIMI grade 3 flow, one patient had TIMI grade 2 flow and the IRA was occluded in three patients. In one of the three patients, the appropriate view was not obtained. In another patient, collateral flow was adequate for near-normal regional wall motion, and in the last, the findings suggested reperfusion of the proximal artery with distal embolic occlusion. Taken together, MCE accurately predicted either TIMI grade 2 flow or less, or TIMI grade 3 flow in 36 of 40 patients. Sensitivity was 87.5%, specificity and positive predictive value were 100% and negative predictive power was 66.7% (P<0.001).

CONCLUSIONS

MCE, together with the electrocardiogram and regional wall motion, can be used to quickly and reliably predict IRA patency early during AMI and may be useful to facilitate a management strategy.

Prognostic value of myocardial viability detected by myocardial contrast echocardiography early after acute myocardial infarction

OBJECTIVES

This study sought to determine whether residual myocardial viability determined by myocardial contrast echocardiography (MCE) after acute myocardial infarction (AMI) can predict hard cardiac events.

BACKGROUND

Myocardial viability detected by MCE has been shown to predict recovery of left ventricular (LV) function in patients with AMI. However, to date no study has shown its value in predicting major adverse outcomes in AMI patients after thrombolysis.

METHODS

Accordingly, 99 stable patients underwent low-power MCE at 7 +/- 2 days after AMI. Contrast defect index (CDI) was obtained by adding contrast scores (1 = homogenous; 2 = reduced; 3 = minimal/absent opacification) in all 16 LV segments divided by 16. At discharge, 65 (68%) patients had either undergone or were scheduled for revascularization independent of the MCE result. The patients were subsequently followed up for cardiac death and nonfatal AMI.

RESULTS

Of the 99 patients, 95 were available for follow-up. Of these, 86 (87%) underwent thrombolysis. During the follow-up time of 46 +/- 16 months, there were 15 (16%) events (8 cardiac deaths and 7 nonfatal AMIs). Among the clinical, biochemical, electrocardiographic, echocardiographic, and coronary arteriographic markers of prognosis, the extent of residual myocardial viability was an independent predictor of cardiac death (p = 0.01) and cardiac death or AMI (p = 0.002). A CDI of < or = 1.86 and < or = 1.67 predicted survival and survival or absence of recurrent AMI in 99% and 95% of the patients, respectively.

CONCLUSIONS

The extent of residual myocardial viability predicted by MCE is a powerful independent predictor of hard cardiac events in patients after AMI.

Comparison between myocardial contrast echocardiography and single-photon emission computed tomography for predicting transmurality of acute myocardial infarction

Contrast-enhanced cardiovascular magnetic resonance imaging (CMR) has been shown to accurately assess transmural extent of infarction, which is an excellent predictor of long-term improvement in contractile function. We assessed the relative accuracy of myocardial contrast echocardiography (MCE) and single-photon emission computed tomography (SPECT) to predict transmural extent of infarction after acute myocardial infarction. MCE, SPECT, and CMR were performed in 40 patients with acute myocardial infarction 7 to 10 days after thrombolysis. CMR was used to divide the transmural extent of infarction into 5 groups: 0%, 1% to 25%, 26% to 50%, 51% to 75%, and 76% to 100% in dysfunctional segments. MCE and SPECT were compared with assessment grades of transmural extent of infarction. There was a significant relation (p<0.0001) between decreasing contrast intensity as assessed qualitatively by MCE and increasing transmural extent of infarction on CMR as was the case for SPECT. The accuracy of MCE (77%) to predict>50% transmural extent of infarction (nonviable myocardium) was significantly (p=0.02) superior to that of SPECT (70%). Absence of uptake on MCE and SPECT virtually ruled out <or=50% of the transmural extent of infarction (negative predictive values 93% and 89%, respectively). MCE was significantly more sensitive than SPECT in differentiating between <or=25% and>25% transmural extent of infarction (84% vs 76%, p=0.03). MCE and SPECT correlate well with the transmural extent of infarction. However, MCE is significantly more accurate in predicting >50% of the transmural extent of infarction and more sensitive in identifying <or=25% of the transmural extent of infarction than SPECT.

Potential clinical applications of myocardial contrast echocardiography in evaluating myocardial perfusion in coronary artery disease

Myocardial contrast echocardiography (MCE) is a relatively new technique that uses microbubbles to produce myocardial opacification. Recent advances in echocardiography have resulted in improved detection of microbubbles within the myocardium allowing combined acquisition of function and perfusion data, thus making MCE suitable for bedside use. Regardless of the imaging modality chosen or the type of stress used, MCE detects changes developing in the coronary microcirculation, providing important information for the evaluation of severity of coronary artery disease and for the detection of viable myocardial tissue in acute or chronic coronary artery disease.

Myocardial Contrast Echocardiography for Distinguishing Ischemic From Nonischemic First-Onset Acute Heart Failure

Background— Distinguishing ischemic from nonischemic origin in patients presenting with acute heart failure (AHF) not resulting from acute myocardial infarction has both therapeutic and prognostic implications. The aim of the study was to assess whether myocardial contrast echocardiography (MCE) can identify underlying coronary artery disease (CAD) as the cause of AHF.

Methods and Results— Fifty-two consecutive patients with AHF with no prior clinical history of CAD and no clinical evidence of acute myocardial infarction underwent resting echocardiography and MCE both at rest and after dipyridamole stress at a mean of 9±2 days after admission. All patients underwent coronary arteriography before discharge. Of the 52 patients, 22 demonstrated flow-limiting CAD (>50% luminal diameter narrowing). Sensitivity, specificity, and positive and negative predictive values of MCE for the detection of CAD were 82%, 97%, 95%, and 88%, respectively. Among clinical, ECG, biochemical, resting echocardiographic, and MCE markers of CAD, MCE was the only independent predictor of CAD ( P <0.0001). Quantitative MCE demonstrated significantly ( P <0.0001) lower myocardial blood flow velocity reserve in vascular territories subtended by >50% CAD (0.59±0.46) compared with patients with normal coronary arteries (1.99±1.00). However, myocardial blood flow velocity reserve in patients with no significant CAD was significantly ( P =0.03) lower compared with control (2.91±0.41). Myocardial blood flow velocity reserve correlated significantly ( P <0.0001) with increasing severity of CAD.

Conclusions— MCE, which is a bedside technique, may be used to detect CAD in patients presenting with AHF without a prior history of CAD or evidence of acute myocardial infarction. Quantitative MCE may further risk-stratify patients with AHF but no CAD.

Ultrasound imaging versus morphopathology in cardiovascular diseases. Coronary collateral circulation and atherosclerotic plaque

This review article is aimed at comparing the results of histopathological and clinical imaging studies to assess coronary collateral circulation in humans. The role of collaterals, as emerging from morphological studies in both normal and atherosclerotic coronary vessels, is described; in addition, present role and future perpectives of echocardiographic techniques in assessing collateral circulation are briefly summarized.