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

Prognostic value of Doppler echocardiographic coronary flow velocity assessment at rest in elderly patients

BACKGROUND

Atherosclerosis and coronary artery disease (CAD) are a common condition and cause of death in the elderly population. There are difficulties with risk assessment in the elderly as the objectification of their symptomatic status can be challenging due to neuromuscular weakness, physical deconditioning or neurological, orthopaedic, peripheral vascular, or respiratory limitations. Non-invasive coronary artery velocity assessment by Doppler method at rest could be helpful in the elderly population. To evaluate the prognostic role of coronary artery ultrasound assessment in a non-selected elderly population in everyday clinical practice.

METHODS

One hundred forty-five patients, aged ≥75years (99 women; 80 ± 4 years), formed the study group. Left coronary artery flows were scanned in addition to conventional echocardiography. During a median follow-up of 26 months, 16 deaths and 2 non-fatal MI occurred.

RESULTS

In multivariable analysis, maximal coronary velocity was the only independent predictor for mortality (heart rate [HR]: 1.02, 95%, CI: 1.01-1.04, p < .0005) and for mortality/MI (HR: 1.02, 95%, CI: 1.01-1.03, p < .0001). The value of 110 cm/s maximal coronary flow velocity (CFL) in the proximal segments of left arteries was the best predictor for death, sensitivity 50%, specificity 90%, p < .005. The annual mortality rate was 16.6% persons/year for patients with elevated CFL ≥110 cm/s. The value 81 cm/s was the best predictor for death/MI, sensitivity 61%, specificity 80%, p < .0005; annual mortality rate was 11.2% persons/year for patients with elevated CFL ≥81 cm/s (p < .0001).

CONCLUSION

Doppler CFL scanning during routine echocardiography is a feasible and valuable tool for assessment of short-term prognosis in elderly patients.

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.

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.