Transthoracic echocardiography in the detection of chronic total coronary artery occlusion

The Role of Multimodality Imaging for Percutaneous Coronary Intervention in Patients With Chronic Total Occlusions

Background

Percutaneous coronary intervention (PCI) of Chronic total occlusions (CTOs) has been traditionally considered a challenging procedure, with a lower success rate and a higher incidence of complications compared to non-CTO-PCI. An accurate and comprehensive evaluation of potential candidates for CTO-PCI is of great importance. Indeed, assessment of myocardial viability, left ventricular function, individual risk profile and coronary lesion complexity as well as detection of inducible ischemia are key information that should be integrated for a shared treatment decision and interventional strategy planning. In this regard, multimodality imaging can provide combined data that can be very useful for the decision-making algorithm and for planning percutaneous CTO recanalization.

Aims

The purpose of this article is to appraise the value and limitations of several non-invasive imaging tools to provide relevant information about the anatomical characteristics and functional impact of CTOs that may be useful for the pre-procedural assessment and follow-up of candidates for CTO-PCI. They include echocardiography, coronary computed tomography angiography (CCTA), nuclear imaging, and cardiac magnetic resonance (CMR). As an example, CCTA can accurately delineate CTO location and length, distal coronary bed, vessel tortuosity and calcifications that can predict PCI success, whereas stress CMR, nuclear imaging and stress-CT can provide functional evaluation in terms of myocardial ischemia and viability and perfusion defect extension.

Additive prognostic value of high baseline coronary flow velocity to ejection fraction during resting echocardiography: 3-year prospective study

BACKGROUND

There is a lack of information about the prognostic value of high velocity in coronary arteries during echocardiography. The present study was aimed at investigating the three-year prognostic value of coronary velocity assessment in all patients who were referred for echocardiography examination.

METHODS

The prospective study comprises 747 consecutive patients. Death, myocardial infarction (MI), acute coronary syndrome (ACS), and/or revascularisation were defined as major adverse cardiac events (MACE). Routine echocardiography was added with coronary velocity assessment in the left main, anterior descending, or circumflex coronary arteries by the Doppler method.

RESULTS

During a median follow-up of 36 months, 192 patients experienced MACE. Deaths occurred more frequently in patients with high local velocity in proximal left-sided segments vs. in middle left-sided segments vs. patients without high coronary velocity (9 vs. 3 vs. 1%, p < 0.0001). Death/MI/ACS occurred in 17 vs. 7 vs. 1%, p < 0.0001, respectively. Age (HR 1.04, 95% CI 1.00; 1.06; p < 0.04), a velocity more than 65 cm/s in any proximal segments of the arteries (HR 4.7, 95% CI 1.9; 11.9; p < 0.002), ejection fraction (HR 0.97, 95% CI 0.94; 0.99; p < 0.007) were strong independent prognostic predictors of death/MI/ACS. The maximal velocity of coronary flow velocity had a significant additive prognostic value to ejection fraction.

CONCLUSIONS

The coronary velocity parameters give long-term prognostic information that can be used to identify persons with a high risk of MACE in consecutive non-selected patients.

The indications and utility of adjunctive imaging modalities for chronic total occlusion (CTO) intervention

Coronary chronic total occlusions (CTO) are common in patients undergoing coronary angiography, yet the optimal management strategy remains uncertain, with conflicting results from randomized trials. Appropriate patient selection and careful periprocedural planning are imperative for successful patient management. We review the role of adjunctive imaging modalities including myocardial perfusion imaging (MPI), cardiac magnetic resonance imaging (CMR), echocardiography and computed tomography coronary angiography (CTCA) in myocardial ischemic quantification, myocardial viability assessment, as well as procedural planning for CTO revascularization. An appreciation of the value, indications and limitations of these modalities prior to planned intervention are essential for optimal management.

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.

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.

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.)