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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4048_Библиотеки_им_академика_М_И_Перельмана
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Fig. 4.6. Accuracy of detecting ≥50% stenosis in the middle proximal LAD
segment.
The limit value blood flow velocity in the point of the LAD bifurcation and the
diagonal artery by ROC analysis was not detected, p<0.06.
The limit value blood flow velocity in the proximal LCx for visual detecting of
≥50% narrowing was 50 cm/s. Sensitivity was 73%, specificity – 88%, accuracy –
81%, p<0.003. Fig. 4.7.
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Fig. 4.7. Accuracy of detecting ≥50% stenosis in the proximal LCx.
Examples of comparing the data of transthoracic ultrasound of coronary arteries,
Doppler ultrasonography and coronary angiography. Fig. 4.8, 4.9.
Fig. 4.8. Transthoracic ultrasound of coronary arteries and coronary angiography
data in one patient.
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173
Fig. 4.9. Transthoracic ultrasound of coronary arteries and coronary angiography
data in one patient.
4.5 Discussion
The research results in a significant correlation between non-invasively measured
coronary blood flow velocities and the degree of stenosis according to invasive
coronary angiography in various LM, LAD and LCx segments. For comparison,
we developed a scheme to divide the proximal LM portions into segments. We
determined the limit values of the ultrasound measurement rates for predicting
≥50% stenosis of these segments. The best comparability was shown for the
middle proximal LAD segment, with the accuracy of 82%. The limit value
velocities in relation to stenosis of LM/proximal LAD segment ranged from 67 to
77 cm/s. Therefore, excessive blood flow velocity in LM over 67 cm/s predicted
stenosis of this region in 89% of cases according to the coronary angiography,
which is a high diagnostic accuracy and is not inferior to other modern
non-invasive methods, including provocative stress tests. So, if blood flow
velocities in LM during transthoracic ultrasound echocardiography are found to
exceed 67 cm/s, patients should be recommended to undergo further invasive
research methods, given the high specificity of this sign. Similarly, excessive blood
flow velocities at the LAD ostium over 77 cm/s and in the middle proximal LAD
over 70 cm/s were specific signs of lesion to the corresponding arterial segments. It
seems advisable to refer patients in whom these pathological velocities are
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determined by ultrasound, for invasive and non-invasive methods of proving
coronary lesions.
Attention is drawn to the inability to identify the limit value blood flow velocity at
the point of bifurcation from the diagonal artery to predict its stenosis by means of
coronary angiography. This may be due to the difficulties in visualizing this area
during routine coronary angiography. Even earlier in previous works, researchers
noted low comparability of the stenosis degree of this segment according to
coronary angiography [47]. Possibly, the study of blood flow velocities in this
segment will further help selecting patients for additional functional invasive
techniques. Further research is required to clarify this issue.
In our work, the limit value velocities were lower than in most of the previously
published works on this topic [8, 28, 56]. This is probably due to the fact that their
studies included patients, predominantly already selected for coronary angiography,
whereas this study sequentially included for selection all patients referred for
echocardiography without initial indications for coronary angiography.
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175
Chapter 5. Prognosis of Patients with Altered Blood Flow According to
Ultrasound Scanning Data. The role of myocardial revascularization in
changing the prognosis in patients with found impaired coronary artery
function according to the transthoracic scanning parameters
5.1 Introduction
In previous chapters, we proved a relation between high coronary artery velocities
with positive stress tests and the presence of significant coronary artery stenoses.
However, it remains unclear whether the high local coronary blood flow velocity
detected during echocardiography at rest is associated with a poor prognosis and
risk of coronary events. Today, the world cardiac surgery practice has no answer to
the question of whether myocardial revascularization is a method to improve the
prognosis of patients with altered velocities in the coronary arteries according to
the data of non-invasive ultrasound diagnostics.
5.2 Purpose of the research
Therefore, the purpose of this part of the research was to determine the prognostic
value of detecting impaired coronary artery function and the effect of myocardial
revascularization on the prognosis of patients with high local coronary flow
velocities at rest (velocity ≥70 cm/s) in the left coronary circulation basin.
5.3 Materials and methods
Patients who were referred for echocardiography between May 2014 and August
2016 were sequentially included in the prospective study. Arterial hypertension,
shortness of breath and known or suspected coronary artery disease or valvular
heart disease were indications for echocardiography. The criterion for inclusion
into the main study group was coronary flow velocities at rest ≥70 cm/s in the left
main artery/pLAD/pLCx or middle LAD/LCx segments. Examples of measuring
blood flow in different portions of the arteries are shown in Figures 5.1-5.7.
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Fig. 5.1 Normal blood flow velocities in the proximal LAD segment.
Fig. 5.2 High velocity and turbulence in LM and at the LAD ostium.
Fig. 5.3 High velocity at the LAD ostium.
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Fig. 5.4 High velocity at the point of LAD bifurcation with the first diagonal
artery.
Fig. 5.5 High velocity in the middle proximal LAD segment.
Fig. 5.6 High velocity in the middle LAD segment.
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Fig. 5.7 Turbulence of blood flow in LM, at the LAD and LCx ostia. High velocity
at the LCx ostium was measured.
The exclusion criterion was previous coronary artery bypass grafting,
unwillingness to provide informed consent. Separately, a control group was deleted
from consecutive patients of comparable age, in whom an increase in coronary
blood flow velocities was not determined.
All patients underwent a survey of complaints to identify the clinical
manifestations of coronary artery disease, arterial hypertension, diabetes mellitus,
and heart failure, as described in Chapter 2. All patients underwent
echocardiography according to the standard protocol supplemented by ultrasound
of the coronary arteries (see Chapter 2). According to indications, a number of
patients underwent stress echocardiography. According to clinical manifestations
and, mainly, with the consent of patients, persons with indications according to the
recommendations of the European Society of Cardiology were referred for
coronary angiography. Coronary angiography was made by independent specialists
in X-ray endovascular surgery. After coronary angiography, according to the
existing recommendations and taking into account the wishes of patients, various
methods of myocardial revascularization were proposed.
Follow-up of the patients continued during the year for an average of 10.5 months.
The data on patient outcomes was collected by interviewing patients or their
immediate relatives, during visits to a doctor or by phone based on the analysis of
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medical records.The following considered to be unfavorable outcomes: death,
myocardial infarction, pulmonary edema, acute coronary syndrome (ACS) and
myocardial revascularization.
5.4 Results
The main group included 361 people: 1) group 1 – 271 person with high velocities
in LM and/or in the proximal portions of LAD/LCx; 2) Group 2 – 90 patients with
high velocities in the middle LAD/LCx. Fifty one person were included as a
control group. Therefore, the final group included 412 patients [141].
5.4.1. Clinical characteristics
The average age of patients in the main group was 62.3±11.2, among them there
were 242 men and 119 women, the average body mass index was 28.6±4.8. Of
them, 299 (83%) suffered from hypertension, 178 (49%) had proven coronary
artery disease, 122 (34%) had past myocardial infarction, 92 (26%) had past
percutaneous coronary intervention, 57 (16%) had a history of diabetes mellitus, 76
(21%) were smokers.
The average age of patients in the control group was 58.4±12.3. There were 27
men and 24 women with the average body mass index of 28.3±3.9. A history of
hypertension was in 38 (75%) persons, proven coronary artery disease and past
myocardial infarction in 7 (14%) and 5 (10%), respectively, percutaneous coronary
interventions in 1 (2%). Diabetes mellitus was in 3 patients (6%) and 3 persons
(6%) from the group were smokers.
5.4.2. Echocardiographic data of the groups.
The groups did not differ significantly in terms of the baseline echocardiographic
parameters. The parameters of the left ventricle volumes and the ejection fraction
are given in Table 5.1.
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Table 5.1. Echocardiographic data
Group 1
N=267
Group 2
N=90
Control group
N=51
p Value
EF, %
61±11
62±10
64±7
NS
EDV of LV, ml
109±35
110±41
103±27
NS
IEDV, ml/m2
56±17
55±20
52±10
NS
LM velocity, cm/s
93±32
46±18
32±8
<0.0001
pLAD/pLCx velocity,
cm/s
102±32
49±24
33±8
<0.0001
mLAD/mLCx velocity,
cm/s
86±33
95±36
30±7
<0.0001
Group 1 – patients with high blood flow velocity in LM and/or in proximal portion
of LAD/LCx; Group 2 – patients with high velocities in the middle LAD/LCx.
EF – ejection fraction, EDV – end-diastolic volume, IEDV – index of EDV, LM –
left main artery; pLAD – proximal portion of left anterior descending artery;
pLCx – proximal portion of left circumflex artery; mLAD – middle portion of left
anterior descending artery; mLCx – middle portion of left circumflex artery.
5.4.3. Stress echocardiographic data.
According to the indications, 309 patients from the three study groups underwent
stress echocardiography: 206 from the first group, 69 from the second and 34 from
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