A Novel Technique to Detect Total Occlusion in the Right Coronary Artery Using Retrograde Flow by Transthoracic Doppler Echocardiography

Coronary artery occlusions diagnosed by transthoracic Doppler

Background

Our aim was to assess whether anterograde flow velocities in septal perforating branches could identify an occluded contralateral coronary artery, and to assess the feasibility and accuracy of diagnosing occlusions in the three main coronary arteries by the combined use of several noninvasive parameters indicating collateral flow.

Methods

A total of 108 patients scheduled for coronary angiography because of chest pain or acute coronary syndromes were studied using transthoracic Doppler echocardiography.

Results

Anterograde peak diastolic flow velocities (pDV) in septal perforating branches were higher in patients with angiographic occluded contralateral artery compared with corresponding velocities in patients without significant disease in the contralateral artery (0.80 ± 0.31 m/sec versus 0.37 ± 0.13 m/sec, p < 0.001). Receiver operating characteristic curve showed pDV ≥ 0.57 m/sec to be the optimal cutoff value to identify occluded contralateral artery, with a sensitivity of 79% and a specificity of 69%. Demonstration of at least one positive parameter (retrograde flow in main coronary arteries, reversed flow in septal perforating and left circumflex marginal branches, pDV ≥ 0.57 m/sec, or demonstration of other epicardial or intramyocardial collaterals) indicating collateral flow to an occluded main coronary artery had sensitivity, specificity, positive and negative predictive value of 89%, 94%, 63%, and 99%, respectively, for detection of a coronary occlusion. With this combined use of several parameters, 25 of 28 coronary occlusions were identified.

Conclusions

By investigating several parameters indicating collateral flow, we were able to identify most of the main coronary occlusions in the patient cohort. Furthermore, our study demonstrated that coronary artery occlusions may result in complex and diverging coronary pathophysiology depending on which coronary artery segment is occluded and the extent of accompanying coronary artery disease.

Trial registration

ClinicalTrials.gov number NTC00281346.

Patient with pseudo-retrograde coronary flow in the normal right coronary artery and left circumflex artery: pitfall of retrograde coronary flow to detect coronary artery occlusion

A 75-year-old lady with hypertension and paroxysmal atrial fibrillation underwent echocardiography to evaluate cardiac function. Transthoracic Doppler echocardiography revealed retrograde coronary flow in the right coronary artery (RCA) and left circumflex artery (LCX). Computed tomographic coronary angiography demonstrated normal but tortuous coronary arteries. This tortuosity of the coronary arteries was thought be a cause of pseudo-retrograde coronary flow in the RCA and LCX. The present case demonstrates a pitfall of retrograde coronary flow for the detection of coronary artery occlusion in daily practice.

A patient came back with retrograde coronary flow in the distal right coronary artery 2 years after coronary intervention: clinical significance of retrograde coronary flow to detect coronary artery occlusion

A 69-year-old male patient, who had a history of coronary stent implantation to the proximal right coronary artery (RCA), presented with exertional chest pain. Transthoracic Doppler echocardiography revealed retrograde coronary flow in the distal RCA, and treadmill stress echocardiography revealed inducible myocardial ischemia in the inferior and posterior segments. Coronary angiography demonstrated a severe stenotic lesion with flow delay in the mid RCA and collateral circulation to the distal RCA from the left coronary artery. Detection of retrograde coronary flow in the distal RCA using transthoracic Doppler echocardiography is a useful method to diagnose subtotal occlusion of the RCA.

Resting coronary flow velocity in the functional evaluation of coronary artery stenosis: study on sequential use of computed tomography angiography and transthoracic Doppler echocardiography

AIMS

Accelerated flow at the site of flow-limiting stenosis can be detected by transthoracic Doppler echocardiography (TTDE). We studied feasibility and accuracy of sequential coronary computed tomography angiography (CTA) and TTDE in detection of haemodynamically significant coronary artery disease (CAD).

METHODS AND RESULTS

We prospectively enrolled 107 patients with intermediate (30-70%) pre-test likelihood of CAD. All patients underwent CTA using a 64-slice scanner. Using TTDE, the ratio of maximal diastolic flow velocity to pre-stenotic flow velocity (M/P ratio) was measured in the coronary segments with stenosis in CTA. In all patients, the results were compared with invasive coronary angiography, including measurement of fractional flow reserve when appropriate. All analyses were done blinded. TTDE was feasible in 276 of 285 evaluated coronary segments. Significant coronary stenoses were associated with a higher M/P ratio than non-significant stenoses (3.59 ± 1.82 vs. 1.28 ± 0.60, P < 0.001). The optimal M/P ratio for detection of significant stenosis was 2.2 (area under receiver operating characteristic curve 0.92, P < 0.001). Compared with the strategy of CTA alone, sequential CTA and focused TTDE had a better positive predictive value (PPV; 61 vs. 78%) and diagnostic accuracy (93 vs. 96%, P = 0.006) without impairment of the negative predictive value (97 vs. 97%).

CONCLUSION

Sequential use of CTA and TTDE is feasible for combined anatomic and functional evaluation of coronary stenoses. Compared with coronary CTA alone, addition of TTDE improved PPV for detection of significant CAD.

Transthoracic echocardiography for imaging of the different coronary artery segments: a feasibility study

Background

Transthoracic echocardiography (TTE) may be used for direct inspection of various parts of the main coronary arteries for detection of coronary stenoses and occlusions. We aimed to assess the feasibility of TTE to visualise the complete segments of the left main (LM), left descending (LAD), circumflex (Cx) and right (RCA) coronary arteries.

Methods

One hundred and eleven patients scheduled for diagnostic coronary angiography because of chest pain or acute coronary syndrome had a TTE study to map the passage of the main coronary arteries. LAD, Cx and RCA were each divided into proximal, middle and distal segments. If any part of the individual segment of a coronary artery with antegrade blood flow was not visualised, the segment was labeled as not satisfactorily seen.

Results

Complete imaging of the LM was achieved in 98% of the patients. With antegrade directed coronary artery flow, the proximal, middle and distal segments of LAD were completely seen in 96%, 95% and 91% of patients, respectively. Adding the completely seen segments with antegrade coronary flow and segments with retrograde coronary flow, the proximal, middle and distal segments of LAD were adequately visualised in 96%, 96% and 93% of patients, respectively. With antegrade directed coronary artery flow, the proximal, middle and distal segments of Cx were completely seen in 88%, 61% and 3% and in RCA in 40%, 28% and 54% of patients. Retrograde coronary artery flow was correctly identified as verified by coronary angiography in seven coronary segments, mainly in the posterior descending artery (labeled as the distal segment of RCA) and distal LAD.

Conclusions

TTE is a feasible method for complete demonstration of coronary flow in the LM, the proximal Cx and the different segments of LAD, but less suitable for the RCA and mid and distal segments of the Cx. (ClinicalTrials.gov number NTC00281346.)

Transthoracic echocardiography in the detection of chronic total coronary artery occlusion

AIMS

The aim of our study was to detect chronic total occlusion of the left anterior descending coronary artery (LAD), circumflex coronary artery (Cx), and right coronary artery (RCA) using transthoracic echocardiography (TTE) in 110 consecutive patients who underwent coronary angiography for investigation of angina.

METHODS AND RESULTS

Coronary blood flow direction was assessed in the epicardial collaterals [distal LAD (dLAD), obtuse marginal branches and right posterior descending artery (PDA)] and intramyocardial collaterals [LAD septal branch (SB LAD) and RCA septal branch (SB RCA)]. The sensitivity and specificity of retrograde flow for identification of the occluded LAD by TTE in the dLAD only were 78 and 96%, respectively, and those in both dLAD and SB LAD were 89 and 96%, respectively. The retrograde SB LAD flow detects proximal LAD occlusion with 88% sensitivity and 75% specificity. The sensitivity and specificity of retrograde flow for identification of the occluded RCA by TTE in the PDA only were 79 and 97%, respectively, and those in both PDA and SB RCA were 89 and 97%, respectively. The retrograde SB RCA flow does not allow us to differentiate between proximal and non-proximal RCA occlusion. Transthoracic echocardiography is not a method for diagnosing Cx occlusions as the success in visualizing the Cx epicardial collaterals was achieved in 31% of cases only.

CONCLUSION

TTE is a sensitive and highly specific non-invasive method for diagnosis of LAD and RCA occlusions, based on the detection of the coronary blood flow direction in the epicardial and intramyocardial collaterals.

Non-invasive assessment of coronary flow and coronary flow reserve by transthoracic Doppler echocardiography: a magic tool for the real world

Transthoracic Doppler echocardiography, introduced in the echo-lab in recent last years, to measure coronary flow and coronary flow reserve, is a very attractive tool, totally non-invasive, and easily available at bedside. This review summarizes the actual possibilities of this tool, its multiple potential clinical applications and diagnostic insights, and its arising prognosis value, in coronary artery disease as in various settings affecting the coronary microcirculation.