Usefulness of the MOSAIC (measurement of stenosis by aliasing coronary flow) method using transthoracic color Doppler echocardiography in unstable angina patients

Noninvasive detection of coronary artery stents by transthoracic echocardiography postprocessing subtraction technique

AIM

To explore the feasibility and value of transthoracic echocardiography (TTE) postprocessing subtraction technique in the detection of a stent in the coronary artery.

METHOD

Transthoracic echocardiography was used to examine 46 coronary artery stents in 30 patients by two-dimensional ultrasound postprocessing subtraction technique. The shape of each stent and its flow patency were observed. The patency was assessed according to blood flow and mosaic flow in the stent. Then, the results were compared with those of percutaneous coronary intervention (PCI) records and coronary angiography (CAG).

RESULTS

Transthoracic echocardiography detected 36 stents among 46 stents (two in the LMCA, 23 in the LAD, seven in the RCA, and two in the LCX); the detection rate was 78.3%. The average length of the stents was 21.8 ± 4.1 mm, and the average diameter was 2.4 ± 0.5 mm; both are shorter than those from PCI records (P < .001). Of the 36 stents, blood flow could be observed in 27. Compared with the results of CAG, TTE had 75% feasibility and 92.6% accuracy in detecting flow patency in the stents.

CONCLUSION

Transthoracic echocardiography postprocessing subtraction technique could be a noninvasive method for detecting a coronary artery stent and, although the measurements of stent length and diameter were shorter than those of PCI records, an accurate detection of flow patency in the stents was achieved.

Prognostic value of proximal left coronary artery flow velocity detected by transthoracic Doppler echocardiography

BACKGROUND

Lesions in the proximal left coronary artery (LCA) are associated with a poor prognosis compared with other lesional sites. Transthoracic Doppler echocardiography (TTDE) can help to detect proximal LCA flow, and an accelerated coronary flow velocity (CFV) indicates the presence of proximal LCA lesions. This study aimed to investigate the prognostic value of CFV in the proximal LCA measured by TTDE.

METHODS

We enrolled 1472 consecutive hemodynamically stable patients with known or suspected heart disease whose CFV was successfully detected using TTDE accompanied by routine echocardiography between 2008 and 2011. The primary outcome was cardiac death (acute myocardial infarction, heart failure, or sudden cardiac death) and patients were followed up over a median of 6.3 years.

RESULTS

Overall, 42 cardiac deaths (3%) were observed. An increased CFV was significantly associated with the outcome in several models based on potential confounders (age, rate pressure product, Framingham Risk Score, diabetes, coronary artery disease, hemoglobin, brain natriuretic peptide, estimated glomerular filtration rate, left ventricular mass, left ventricular ejection fraction, and E/e'). Using a receiver operating characteristic curve analysis, the optimal cut-off value for the CFV to the association of the outcome was 37 cm/s (area under the curve, 0.70; sensitivity, 82%; specificity, 62%). In sequential Cox proportional hazards models, the CFV added incremental prognostic information to the clinical and basic echocardiographic parameters (chi-squared: 110.7 to 146.6, P < 0.01).

CONCLUSIONS

An increased CFV in the proximal LCA was associated with cardiac death, incremental to the clinical and basic echocardiographic parameters.

An echocardiographic clue for ostial left main coronary artery stenosis

Calcified nodules in human coronary arteries are usually focally distributed. Non-invasive imaging of coronary arteries by bedside emergency transthoracic echocardiography in adults is possible and may become a useful adjunct to other methods of coronary artery examination. Coronary artery stenosis can be identified as localized color aliasing and accelerated flow velocities. Complete visualization of individual ostial coronary segments might ease the demonstration of coronary stenosis by bedside transthoracic echocardiography. The left main coronary artery stenosis requires prompt emergency evaluation and treatment because emergency conditions have higher mortality rates. The authors wish to emphasize the usefulness of emergency bedside echo-Doppler for a prompt diagnosis and treatment of this life-threatening condition.

Transthoracic Doppler for detection of stenoses in the three main coronary arteries by use of stenotic to prestenotic velocity ratio and aliased coronary flow

AIMS

Our aim was to determine the feasibility and accuracy of diagnosing significant coronary artery stenoses using peak stenotic to prestenotic velocity ratio (pSPVR) measurements when compared with results from quantitative coronary angiography and coronary flow velocity reserve (CFVR) assessed by transthoracic echocardiography (TTE).

METHODS AND RESULTS

One hundred and eight patients scheduled for coronary angiography were studied using transthoracic Doppler echocardiography. Stenoses were identified by local colour aliasing by colour flow Doppler, and further evaluated by pSPVR, using a pSPVR of ≥2.0 as a cut-off for significant stenosis. When pSPVR could not be measured, local mosaic coronary flow pattern at Nyquist limit ≥0.48 m/s was used. Sixty-five lesions suggestive of stenosis were found by TTE. Combining findings of pSPVR ≥2.0 and local mosaic flow at Nyquist limit ≥0.48 m/s, the sensitivity and specificity of demonstrating significant stenoses (diameter stenosis, 50-99%) in the left main coronary artery (LM), left anterior descending coronary (LAD), left circumflex coronary (Cx), and right coronary artery (RCA) were 75 and 98%, 74 and 95%, 40 and 87%, and 34 and 98%, respectively. The pSPVR did not differ significantly between arteries with reduced and normal CFVR, with a cut-off of CFVR <2.0.

CONCLUSIONS

Findings of pSPVR ≥2.0 or localized colour flow aliasing are useful in the non-invasive diagnosis of significant coronary disease in the three main coronary arteries, with high specificity for detecting significant stenoses. These findings showed high sensitivity for identifying significant stenoses in the LM and LAD, but showed lower ability to detect those lesions in the Cx and RCA.

Role of transthoracic Doppler echocardiography in patients with a proximal left coronary artery lesion that cannot be diagnosed by computed tomography angiography

The diagnosis of lesions with severe calcium or in-stent stenosis using coronary computed tomography angiography (CCTA) is still difficult. The aim of the present study was to evaluate the accuracy of transthoracic Doppler echocardiography (TTDE) in patients with suspected angina pectoris, who had a proximal left coronary artery (LCA) site that could not be evaluated by CCTA. Fifty-eight patients were evaluated. The proximal LCA was defined as the left main coronary artery and proximal left anterior descending coronary artery. All patients underwent TTDE and had coronary angiography performed as a reference method. We measured the proximal left coronary flow velocity (CFV) by both color and pulse Doppler methods. Proximal coronary flow was detected in 45 (78%) of 58 patients. CFVs measured by both methods were significantly greater in the group with severe stenosis (percent diameter stenosis >70%) than in the groups with moderate stenosis (percent diameter stenosis 40% to 70%) or without stenosis (color Doppler: 148 ± 42 cm/s, 89 ± 40 cm/s, and 41 ± 22 cm/s, respectively, p <0.05; pulse Doppler: 143 ± 61 cm/s, 82 ± 33 cm/s, and 39 ± 17 cm/s, respectively, p <0.05). Receiver operating characteristic curve analysis showed that the optimal CFV cut-off values obtained by color and pulse Doppler to diagnose severe stenosis were 92 cm/s (sensitivity, 100%; specificity, 90%) and 81 cm/s (sensitivity, 100%; specificity, 85%), respectively. In conclusion, TTDE could diagnose proximal LCA stenosis with good accuracy in patients who could not be evaluated by CCTA.