Coronary angiography (coronary angiography)

Coronary angiography continues to be the "gold standard" for diagnosing coronary artery stenoses, determining the effectiveness of drug therapy, PCI and CABG.

Coronary angiography is the contrasting of the coronary arteries under X-ray control with the introduction of RKV into the mouth of the arteries and the recording of the image on the X-ray film and video camera. Increasingly, they use the computer's hard disk and CD disks, while the image quality does not deteriorate.

[1], [2], [3], [4]

Indication for coronarography

In recent decades, indications for coronary angiography have been expanding all the time due to the proliferation of such methods of treatment of coronary atherosclerosis and ischemic heart disease such as TBCA with stenting and CABG coronarography are used to assess the coronary bed (narrowing and their extent, severity and localization of atherosclerotic changes) and prognosis in patients with IHD symptoms. It is also very useful for studying the dynamics of coronary tone, immediate and distant results of TBA, CABG and drug therapy. In short, the indications for coronary angiography can be formulated as follows:

1. inadequate effectiveness of drug therapy in patients with ischemic heart disease and solution of the issue of other treatment tactics (TBCA or CABG);
2. diagnosis and differential diagnosis in patients with an unclear diagnosis of the presence or absence of IHD, cardialgia (difficult-interpreted or questionable data of non-invasive and stress tests);
3. determination of the coronary bed in representatives of occupations associated with increased risk and responsibility in cases of suspected presence of signs of IHD (pilots, cosmonauts, drivers of transport);
4. AMI in the first hours of the disease for carrying out (intracoronary) thrombolytic therapy and / or angioplasty (TBA) in order to reduce the necrosis zone; early postinfarction angina or relapse of MI;
5. evaluation of CABG results (patency of aortocoronary and mammarocoronary shunts) or PCI in case of relapses of angina attacks and myocardial ischemia.

Method of coronary angiography

Coronarography can be performed both separately and together with the catheterization of the right heart and left (less often right) HF, myocardial biopsy, when along with the evaluation of the coronary bed it is also necessary to know the parameters of pressure in the prostate, right atrium, pulmonary artery, minute volume and cardiac index , indicators of total and local contractility of the ventricles (see above). Coronary angiography should be provided with constant ECG and blood pressure control, a general blood test should be performed and biochemical indices, blood electrolytes composition, coagulogram, urea and blood creatinine indices, tests for syphilis, HIV, hepatitis should be evaluated. It is also desirable to have a chest X-ray and duplex scanning of the vessels of the ileum-femoral segment (if the femoral artery is punctured, which so far happens in most cases). Indirect anticoagulants are canceled 2 days before the planned coronary angiography with coagulation control. Patients with an increased risk of systemic thromboembolism (atrial fibrillation, mitral valve defect, history of episodes of systemic thromboembolism) during the abolition of indirect anticoagulants may receive intravenously unfractionated heparin or subcutaneously low-molecular-weight heparin for the period of coronary angiography. With a planned CAG, the patient is delivered to the X-ray surgical room on an empty stomach, premedication consists of parenteral administration of sedative and antihistamines. The attending physician should receive written informed consent from the patient for the procedure, indicating the rare but possible complications of this technique.

The patient is placed on the operating table, ECG electrodes are applied to the extremities (precardial electrodes should also be on hand if necessary). After processing the puncture site and isolating it with sterile laundry, local anesthesia is done at the point of artery puncture and an artery is punctured at an angle of 45 °. Upon reaching the blood stream from the pavilion, a 0.038 0.035 inch conductor is inserted into the puncture needle, the needle is removed and an introducer is placed in the vessel. Then, usually 5000 IU of heparin is administered bolus or the system is constantly washed with heparinized isotopic sodium chloride solution. The introducer introduces a catheter (various types of coronary artery catheters are used for the left and right coronary arteries), it is advanced under fluoroscopic control to the aortic bulb and catheterized coronary arteries under the control of the blood pressure from the catheter's tail. The size (thickness) of the catheters varies from 4 to 8 F (1 F = 0.33 mm) depending on the access: femoral catheters use 6-8 F, and radial - 4-6 F. Using a syringe with RVB 5-8 ml manually contrast the selectively left and right coronary arteries in different projections using cranial and caudal angulations, trying to visualize all segments of the artery and their branches.

In case of detection of stenoses, two orthographic projections are performed to more accurately assess the degree and eccentricity of stenosis: if in LCA, we usually get up in the right anterior oblique projection or straight (so the LCA barrel is better controlled), in the right oblique projection .

The LCA originates from the left coronary sinus of the aorta with a short (0.5-1.0 cm) trunk, after which it divides into the anterior descending (PNA) and envelope (OA) artery. The PNA follows the anterior interventricular groove of the heart (it is also called the anterior interventricular artery) and gives diagonal and septal branches, blood supply to the vast area of the myocardium of the LV - the front wall, the interventricular septum, the apex and part of the lateral wall. OA is located in the left atrioventricular groove of the heart and gives the branches of the obtuse margin, left atrial and with the left type of blood supply the posterior-descending branch, blood supply to the LV lateral wall and (rarely) the LV lower wall.

The PCA departs from the right aorta from the right coronary sinus, goes to the right atrioventricular groove of the heart, the conical and sinus node gives the branches in the proximal third, the right ventricle artery in the middle third, the artery of the acute margin in the distal third, the posterolateral one atrioventricular node) and posterior-descending arteries. PKA blood supply to the prostate, pulmonary trunk and sinus node, LV lower wall and adherent interventricular septum.

The type of blood supply of the heart is determined by which artery forms the posterior-descending branch: approximately in 80% of cases it departs from the PCA - the right type of blood supply to the heart, 10% from OA - left type of blood supply and 10% from PCA and OA - or a balanced type of blood supply.

Arterial access for coronarography

The choice of access to coronary arteries, as a rule, depends on the operating physician (his experience and preferences) and on the condition of the peripheral arteries, the coagulation status of the patient. The most commonly used, safe and widespread femoral approach (femoral artery large enough, does not collapse even in shock, is far from vital organs), although in some cases other ways of introducing catheters (axillary, axillary, brachial, brachial, radial, or radial). Thus, in patients with atherosclerosis of the vessels of the lower extremities or operated earlier on this occasion, in outpatients a puncture of the arteries of the upper extremities (humerus, axillary, radial) is used.

In the femoral, or femoral, way, the anterior wall of the right or left femoral artery is well palpated and punctured 1.5-2.0 cm below the inguinal ligament in Seldinger's method. Puncture above this level leads to difficulties in the digital arrest of bleeding after removal of the introducer and to a possible retroperitoneal hematoma, below this level - to the development of pseudoaneurysm or arteriovenous fistula.

In the axillary method, the right axillary artery is often punctured, and more rarely the left one. At the border of the distal region, the armpits palpate the pulsation of the artery, which is punctured in the same way as the femoral, after local anesthesia followed by insertion of the introducer (for this artery, we try to take catheters no larger than 6 F for easier stopping of bleeding and reducing the probability of hematoma development in this place of puncture after the study). This method is currently used by us rarely because of the introduction of radial access a few years ago.

Brachial, or brachial, method was used for a long time: still Sones in 1958 applied it for selective catheterization of the coronary arteries, making a small cutaneous incision and secreting the artery with the application of a vascular suture at the end of the procedure. When the author performed this method, there was not much difference in the number of complications compared with femoral artery puncture, but his followers had a greater frequency of vascular complications (distal embolization, arterial spasm with impaired blood supply to the extremities). Only in a few cases this access is used because of the vascular complications listed above and the difficulty of fixing the brachial artery during its percutaneous puncture (without cutaneous incision).

Radial method - puncture of the radial artery on the wrist - has become more frequent in the last 5-10 years for outpatient coronary angiography and rapid activation of the patient, the thickness of the introducer and catheters in these cases does not exceed 6 F (more often 4-5 F) femoral and brachial accesses, catheters 7 and 8 F can be used (this is especially important in complex endovascular interventions where two or more conductors and balloon catheters are required in the treatment of bifurcation lesions with stenting).

Prior to the puncture of the radial artery, the Allen test is performed with the radial and ulnar artery clamping for collateralization in the event of complication after the procedure - occlusion of the radial artery.

The puncture of the radial artery is performed with a thin needle, then an introducer is placed in the vessel into the vessel, which is then injected with a cocktail of nitroglycerin or isosorbide dipitrate (3 mg) and verapamil (2.5-5 mg) to prevent spasm of the artery. For subcutaneous anesthesia, use 1-3 ml of a 2% solution of lidocaine.

With radial access, it may be difficult to conduct the catheter in the ascending part of the aorta due to the tortuosity of the humerus, right subclavian artery and brachiocephalic trunk, often other coronary catheters (not Jadkins, like with femoral access) of the Amplatz type and multi-profile catheters to reach the coronary arteries .

[5], [6], [7], [8]

Contraindications to coronary angiography

Absolute contraindications at the moment for large catheterization angiographic laboratories are not, except for the patient's refusal to perform this procedure.

Relative contraindications are as follows:

• uncontrolled ventricular arrhythmias (tachycardia, fibrillation);
• uncontrolled hypokalemia or digitalis intoxication;
• uncontrolled arterial hypertension;
• various feverish conditions, active infective endocarditis;
• Decompensated heart failure;
• disorders of the blood coagulation system;
• severe allergy to RVC and intolerance to iodine;
• severe renal failure, severe damage to the parenchymal organs.

Risk factors for complications after cardiac catheterization and coronary angiography should be considered: elderly age (over 70 years), complex congenital heart diseases, obesity, malnutrition or cachexia, uncontrolled diabetes mellitus, pulmonary insufficiency and chronic obstructive pulmonary disease, renal failure with a blood creatinine level greater than 1 , 5 mg / dl, tri-vascular coronary lesion or lesion of the LKA trunk, angina pectoris IV, defects of the mitral or aortic valve (as well as the presence of artificial valves), LVEF < 35%, low exercise tolerance according to treadmill test data (or other stress tests), accompanied by hypotension and severe myocardial ischemia, pulmonary hypertension (pulmonary artery systolic pressure more than 30-35 mm Hg), pulmonary artery wedge pressure more than 25 mm Hg. Art. Vascular risk factors for complications of coronary angiography: disorders of the blood coagulation system and increased bleeding, arterial hypertension, severe peripheral vascular atherosclerosis, recent stroke, marked aortic insufficiency. Patients with these risk factors should be carefully observed with monitoring hemodynamics, ECG at least 18-24 h after coronary angiography and catheterization. Coronary angiography performed for emergency indications is also associated with an increased risk of complications during and after the procedure, which requires compliance with the risk / benefit principle for the patient.

[9], [10], [11]

Determination of the degree of stenosis and variants of the lesion of the coronary bed

Stenoses of the coronary arteries are divided into local and diffuse (extended), uncomplicated (with smooth, even contours) and complicated (with uneven, irregular, undercut contours, WBC flowing into the sites of ulceration of the plaque, and parietal thrombi). Uncomplicated stenoses usually occur with a stable course of the disease, complicated - in almost 80% of cases, occur in patients with unstable angina, ACS.

Hemodipamically significant, i.e., limiting the coronary blood flow, is considered narrowing the diameter of the vessel by 50% or more (but this area corresponds to 75%). However, stenoses less than 50% (the so-called non-obstructive, non-stenosing coronary atherosclerosis) can be prognostically unfavorable in the event of plaque rupture, formation of a parietal thrombus with the development of instability of the coronary circulation and AMI. Occlusion - complete overlapping, blockage of the vessel along the morphological structure - there are cone-shaped (slow progression of the constriction followed by complete closure of the vessel, sometimes even without myocardial infarction) and with a sharp clot of the vessel (thrombotic occlusion, most often with AMI).

There are various options for quantifying the prevalence and severity of coronary atherosclerosis. In practice, a simpler classification is more often used, considering the three main arteries (PNA, OA and PKA) as the main ones, and highlighting one-, two- or three-vessel lesions of the coronary bed. Separately indicate the lesion of the trunk of the LCA. Proximal significant stenosis of PNA and OA can be considered equivalent to lesion of the LCA trunk. Large branches of the 3 main coronary arteries (intermediate, diagonal, blunt margins, posterolateral and posteriorly) are also taken into account in assessing the severity of the lesion and, like the main ones, may be endovascular (TBA, stenting) or bypass.

It is important for the polypositional contrast of the arteries (at least 5 projections of the LCA and 3 - PCA). It is necessary to exclude the stratification of branches on the stenotic portion of the vessel under study. This makes it possible to avoid underestimation of the degree of constriction in the eccentric arrangement of the plaque. This should be remembered in the standard analysis of angiograms.

Selective contrasting of venous aortocoronary and aortoarterial (internal thoracic artery and gastro-omental artery) shunts is often included in the plan of coronary angiography in patients after CABG to assess the patency and functioning of shunts. For venous shunts starting at the anterior aorta wall about 5 cm above the PCA orifice, coronary JR-4 and modified AR-2 catheters are used, JR or IM for the internal mammary artery, and the Cobra catheter for the gastro-omental.

[12], [13], [14], [15], [16], [17], [18]

Complications of coronary angiography

Mortality in coronary angiography in large clinics is less than 0.1%. Serious complications, such as myocardial infarction, stroke, severe arrhythmias and vascular injury, occur in less than 2% of cases. There are 6 groups of patients who have a risk of serious complications:

• children and persons over 65 years of age, and in elderly women the risk is higher than that of older men;
• patients with angina pectoris IV FK, they have a higher risk than patients with angina pectoris I and II FK;
• in patients with lesion of the LKA trunk, complications are 10 times more likely than in patients with a lesion of 1-2 coronary arteries;
• patients with valvular heart disease;
• patients with left ventricular failure and LVEF <30-35%;
• patients with various non-cardial pathologies (renal failure, diabetes, cerebrovascular pathology, pulmonary diseases).

In two large trials, patients who underwent catheterization and coronary angiography had a mortality rate of 0.1-0.14%, myocardial infarction 0.06-0.07%, cerebral ischemia or neurologic complications 0.07-0.14%, reactions on RCV - 0.23 and local complications at the site of puncture of the femoral artery - 0.46%. In patients with the use of the brachial and axillary arteries, the percentage of complications was slightly higher.

The number of deaths increases in patients with lesion of the LCA trunk (0.55%), with severe heart failure (0.3%). Various disorders of rhythm - extrasystole, ventricular tachycardia, ventricular fibrillation, blockade - can occur in 0,4-0,7% of cases. Vazovagalnye reactions are found, but our data, in 1-2% of cases. This is expressed in a decrease in blood pressure and related cerebral hypoperfusion, bradycardia, blanching of the skin, cold sweat. The development of these phenomena is determined by the patient's anxiety, the reaction of painful stimuli during arterial puncture and the stimulation of the chemo- and mechanoreceptors of the ventricles. Typically, it is sufficient to use ammonia, raise the legs or the foot end of the table, less often requires intravenous injection of atropine, mezaton.

Local complications occur, according to our data, in 0.5-5% of cases with different vascular accesses and consist in a hematoma at the puncture site, infiltrate and false aneurysm.

[19], [20], [21], [22], [23], [24], [25]

Congenital anomalies of coronary circulation

Coronary arteriovenous fistulas are a fairly rare pathology, consisting in the presence of a connection between the coronary artery and any cavity of the heart (most often - the right atrium or the ventricle). The discharge of blood is usually small, myocardial blood flow does not suffer from this. In 50% of these patients, there is no symptomatology, the other half may develop symptoms of myocardial ischemia, CH, bacterial endocarditis, and rarely - pulmonary hypertension. Fistulae from the PKA and its branches are more common than the fistulae of PNA and OA.

Resetting of blood in the prostate is observed in 41% of fistulas, in the right atrium - in 26%, in the pulmonary artery - in 17%, in the left ventricle - in 3% of cases and in the upper vena cava - in 1%.

If the fistula moves away from the proximal portion of the coronary artery, the site of the abnormality can be determined using echocardiography. The best method of diagnosing pathology is the KGA.

Departure of the LCA from the pulmonary artery trunk is also a rare pathology. This anomaly manifests itself in the first months of life of heart failure and myocardial ischemia. In this case, the total perfusion of the myocardium by LCA is stopped and is carried out only by PCA, and it can be sufficient if collateral blood flow from PCA to LCA develops.

Usually in these patients in the first 6 months. Life develops MI, which subsequently leads to death in the first year of life. Only 10-25% of them survive without surgical treatment before childhood or adolescence. During this time they develop persistent ischemia of the myocardium, mitral regurgitation, cardiomegaly and heart failure

When contrasting the ascending aorta, one can see the departure from the aorta of the PKA alone. In the later shots, you can see by collaterals filling PN A and OA with the discharge of contrast into the pulmonary trunk. One of the methods of treatment of adult patients with an abnormal departure from the pulmonary trunk is the application of a venous shunt to the LCA. The outcome of such an operation and the forecast largely depend on the degree of myocardial damage. In very rare cases, it departs from the pulmonary artery of the PCA, rather than the LCA.

Also, such anomalies as the departure of the LCA from the PCA and OA from the PCA or near the PCA's mouth are rarely observed.

In a recent publication, the percentage of occurrence of some coronary artery anomalies is indicated: the departure of PNA and OA by separate mouths - 0.5%, the onset of OA from the right sinus of Valsalva is 0.5%. Divergence of the PCA estrus from the ascending aorta above the right sinus of Valsalva - 0.2%, and from the left coronary sinus - 0.1%, arteriovenous fistula - 0.1%, the passage of the LCA from the right coronary sinus of the aorta - 0.02%.

[26], [27], [28], [29], [30]

Collateral blood flow

In a normal heart with unchanged coronary arteries of collaterals (small anastomotic branches connecting large coronary arteries) but CAG is not visible, as they are in a collapsed state. In obstructive lesions of one artery, a pressure gradient is created between the distal portion of the vessel with gynoperfusion and a normally functioning vessel, as a result of which the anastomotic channels open and become angiographically visible. It is not completely clear why some patients develop effectively functioning collaterals, while others do not. The existence of collateral blood flow around the obstruction of the artery protects the area of myocardial gynoperfusion. Collaterals begin to be visualized, as a rule, when the vessel is narrowed by more than 90% or when it is occluded. In one study in patients with AMI and occlusion of ISA, coronarography for the first time in 6h AMI revealed collaterals in only 50% of cases, and CAG after 24 hours of AMI in almost all cases. This confirmed that collateralization after occlusion of the vessel develops rather quickly. Another factor in the development of collateral blood flow is the condition of the artery that will give collaterals.

Collateral intersystemic and intrasystemic blood flow plays an important role in the stenotic lesion of the coronary bed. In patients with complete occlusion of the vessel, LV regional contractility is better in those segments of the ventricle that are supplied with collateral blood flow than in those in which there is no collateralization. In patients with AMI without prior TLT, an emergency CAG showed that persons with adequately developed collaterals had a lower LV CSF, higher SI and LVEF, lower percentage of myocardial asynergy than those who did not have collaterals. When carrying out TBCA, inflation of the balloon at the site of arterial stenosis caused a less pronounced pain response and a change in the EC segment of the ECG in those patients in whom collaterals were well developed, compared to those with poor development.

[31], [32], [33], [34], [35], [36], [37], [38]

Errors in coronary angiography

Single-shot evaluation, multi-projection survey of the vessel with the determination of all proximal, middle and distal segments of the artery and its branches, good quality of angiograms, expert's expert look helps to avoid errors in the conduct and interpretation of CAG data.

Interpretation of the coronary arteries is complicated by a lack of clear contrasting of the coronary arteries. Normal unchanged coronary arteries have smooth contours on the coronarography, with a free passage of the contrast medium, good filling of the distal bed, and lack of fuzziness and irregular contours. For a good visualization of all segments of the artery, there should be a good filling with the contrast of the vascular bed, which is possible with a tight filling of the artery by manually introducing the RVB. Filling a vessel often happens poorly with catheters with a smaller internal diameter (4-5 F), which are used in transradial coronary angiography. Inadequate filling of the coronary artery with contrast can lead to a conclusion about a vertebral lesion, irregular contours, a parietal thrombus.

Super selective deep catheterization of LCA, especially in patients with a short trunk, with the introduction of a contrast agent in OA, may erroneously indicate PNA occlusion. Other reasons for the insufficiently tight filling of the contrast medium may be a poor semi-selective cannulation of the artery's anterior end (it is necessary to select a catheter corresponding to coronary anatomy), increased coronary blood flow in myocardial hypertrophy (arterial hypertension, hypertrophic cardiomyopathy, aortic insufficiency), too wide venous aortocoronary shunt.

Intravascular ultrasound and the determination of the pressure gradient in stenosis help in diagnostically complex cases in evaluating the significance of vessel constriction.

Unrecognized occlusions of branches of large coronary arteries can be determined only in late frames of angiography when filling the distal segments of the occluded branch along collateral lines.

The superposition of large branches of the LCA in the left and right oblique projections sometimes makes it difficult to visualize the stenoses or occlusions of these vessels. Using caudal and cranial projections helps to avoid errors in diagnosis. The first septal branch of the PNA, when the PNA itself is occluded immediately after its withdrawal, is sometimes mistaken for the PNA itself, especially as this branch expands in order to create a collateral blood flow to the distal PNA.

"Muscular bridges" - systolic contraction of the coronary artery, when its epicardial part "dives" into the myocardium; are manifested by the normal diameter of the vessel in the diastole and the narrowing of the short section of the artery going under the myocardium into the systole. Most often these phenomena are observed in the basin of the PNA. Although coronary blood supply mainly occurs in the diastole phase, it sometimes describes cases of myocardial ischemia, angina pectoris and myocardial infarction as a result of pronounced systolic clamping together of the "muscle bridge". There are also paroxysms of atrioventricular block, episodes of ventricular tachycardia during exercise or sudden death. Effective therapy for these conditions includes the use of beta-blockers and in very rare cases, surgical treatment.

Cardiac catheterization and catheterization, coronary angiography and ventriculography retain their high informativeness, accuracy and reliability in the diagnosis and treatment of various forms of cardiovascular diseases and continue to be the "gold standard" in determining the tactics of treating various pathological conditions of the heart and blood vessels.

[39], [40], [41], [42], [43],