Keywords: coronary artery, coronary heart disease, myocardial infarction, endovascular intervention.
Despite the perfection of technology, endovascular interventions on coronary arteries (CA) do not exclude the probability of unsatisfactory treatment results and even lethal outcomes (4). This fact from the clinician's point of view can be explained by many different aspects, including both procedural, pre- and post-hospital complications, quality of antiplatelet therapy, biological features of stents, stenosis morphology, etc. Unsatisfactory result of stenting is the return of angina pectoris after a certain period of time, decreased tolerance to physical activity, which is due to restenosis and/or complete occlusion of stented areas, the appearance of atherosclerotic narrowing of coronary vessels in other places (de novo) [6]. During endovascular interventions on coronary arteries (CA) a variety of complications are possible, regardless of age. This fact can be explained by different degrees of atherosclerosis, the number of stenoses in the arteries, their morphological features, individual characteristics of the organism, etc.
It is necessary to consider and analyse previous research results [1] in order to reduce in-stent complications, occlusions, thromboembolic complications, formation of new foci of occlusion, repeated myocardial infarctions, a sharp decrease in myocardial contractility, Currently, there is a need to assess the impact of endovascular procedure on the clinical course of the disease and complications in the immediate period after endovascular treatment [5].
Research aim. To assess the degree of clinical effectiveness of direct coronary artery stenting in CHD patients undergoing a hospital treatment.
Material and Methods. The study enrolled 117 CHD patients who underwent angiographic study of CA, including 86 (73.5 %) male (mean age 56.1±1.8 years) and 31 (26.4 %) female (mean age 58.0±1.9 years). The overall mean age of the patients examined was 57.5±0.6 years. All the examined patients had a documented diagnosis of CHD, stable angina pectoris II-IV functional class. Demographic data were collected in all patients, including a medical history of angina pectoris, the presence of previous myocardial infarctions (MI), and risk factors for atherosclerosis. During the examination, the functional class of angina pectoris, the form of CHD, the localisation of ischaemia and its degree was assessed by angiography. During diagnostic coronary angiography the number and localisation of stenoses were identified and quantitative coronary analysis was performed to assess the feasibility of stenting. The mean duration of CHD was 4.8±0.6 years in men and 5.2±0.4 years in women. The mean duration of AH (arterial hypertension) in men was 8.0±0.2 years, in women, 6.0±0.6 years. 10 (8.5 %) patients had a history of acute MI, of whom 3 patients had a large focal MI, 7 patients had a small focal MI. There were no patients with exertional angina pectoris (EA) 0 and I grade CT (Coronary Tendons) before hospitalization. CHD EA of II grade CT was in 36 (30.8 %) patients, III grade — in 47 (40.2 %) patients, IV grade — in 34 (29.1 %) patients. Stable CT grade was determined according to the classification of the Canadian Heart Association. After CAG (cardioangiography), the result was considered as clinically effective when symptoms of angina pectoris disappeared or significantly decreased in the absence of complications (cardiac death or non-fatal MI) and angina pectoris attacks, as well as in the reduction of nitroglycerin requirement. Angiographic success was considered in the absence of residual stenosis of less than 30 % at the site of stent implantation with restoration of blood flow TIMI (thrombolysis in myocardial infarction) 3, signs of vascular wall dissection, stent thrombosis, subcutaneous haematoma.
The material was statistically processed using the Statistica (v.6.0) statistical software package,
Results and their consideration . All patients underwent stenting and stent implantation was successful in 100 % of cases. Overall 260 stenoses were revealed, 24 (20.5 %) of them had stenosis degree of 60–70 %, 46 (39.3 %) — 70–80 %, including chronic occlusions — 17 (14.5 %), 47 (40.1 %) stenoses had stenosis degree more than 80–90 %. According to Mehran classification local type — 21 stenoses, diffuse type — 41 stenoses, diffuse-proliferative type — 79 stenoses and occlusion — 17 stenoses.
Stenotic-occlusive lesions of the anterior interventricular branch were the most common in the patient group with 78 (66.7 %) cases, the right coronary artery with 35 (29.9 %) cases, and the LCA trunk with 4 cases (3.4 %). Diagonal branch lesions were observed in 15 (12.8 %) and marginal artery lesions in 5 (4.2 %) (Table 1).
Angiographic characteristics of CHD patients included in the research
Table 1
|
Indicator |
Men n=86 |
Women n=31 |
Total |
|
Number of stenoses |
260 |
||
|
One |
21 |
11 |
32 (27,4 %) |
|
Two |
31 |
9 |
40 (34,2 %) |
|
Three |
38 |
7 |
45 (38,4 %) |
|
Degree of stenosis (%) |
|||
|
60–70 % |
13 |
11 |
24 |
|
70–80 % |
41 |
5 |
46 |
|
80–90 % |
38 |
9 |
47 |
|
Chronic occlusions |
11 |
6 |
17 |
Note: % calculated from the total number of people examined 224 stents were treated in men and 31 in women. The results showed that in most cases two (39.3 %) and three (40.1 %) vascular lesions of coronary arteries were registered in men while these figures were significantly lower in women (11.1 % and 2.6 % respectively). The same trend is observed in the degree of coronary stenosis. Significant degree of coronary stenosis (more than 70 %) is found in males and they are more likely to have a double-vessel lesion with a significant degree of stenosis compared to females. Among many factors determining the success of endovascular intervention is the absence of early and late complications. The results of the treatment of 117 patients showed that the majority of patients had improved both clinical and angiographic symptoms undergoing the hospital treatment. In most patients after stenting, angina pectoris attacks decreased or disappeared, their performance improved and ECG symptomatology improved. However, 2 (1.7 %) patients had intermittent attacks of retrosternal pain, which was associated with tricuspid arterial disease and stenosis more than 90 %.
According to the literature, angiographic success rate in specialised clinics reaches 85–95 % of patients, and complications are reported in 6–7 % of cases [2]. Among the most frequent complications, restenosis develops in 20–40 % of patients after stenting, requiring repeated revascularization [3]. The results of angiographic examination performed immediately after stenting procedure have shown that angiographic success with restenotic blood flow restoration up to TIMI 3 has been achieved in 108 (92.3 %) patients with stenoses. However, in 9 patients angiographically after stent placement the vessel lumen was visible, antegrade blood flow with filling of the postocclusive segment was determined, but the filling was delayed or indistinct, i.e. the blood flow was restored to TIMI 2, and among them 6 patients, had initially chronic occlusions. The number of stents per treated patient averaged 2.2, depending on gender for men 2.7 and for women 1.8.
Angiographic complications of subcutaneous haematoma occurred in 7 (6.0 %) patients, all of whom were male. One patient had a subfebrile temperature after the procedure, which disappeared on the second day. In our observations, the main causes of complications after endovascular intervention were dissection (2.5 % of cases) at the distal end of the stent, lateral branch occlusion in bifurcation lesions and acute stent thrombosis (1.7 % of cases). In all cases (except for one), repeated endovascular interventions resolved the angiographic complications and stabilized the patients. 10 (8.5 %) patients had recurrent angina pectoris after stenting, 5 (4.2 %) of which revealed residual stenosis over 50 % of the vessel diameter. In this group of patients, 2 patients developed nonfatal MI, which was confirmed by the corresponding changes on ECG and increased levels of cardiac markers, among the most common were subcutaneous hematoma (in 3 patients), arterial intimal desection (2 patients), residual arterial stenosis over 50 % (5 patients), and among the most life-threatening outcomes, development of nonfatal MI was not excluded.
In order to determine the reserve capacity of coronary blood flow after myocardial revascularization by stenting, we analysed the results of Bicycle ergometer test. The findings were distributed according to the number of affected arteries. The result of Bicycle ergometer test was positive in most patients preliminary to stenting After stenting in patients with univessel disease, the test was positive in 12 (30.0 %) patients, in 18 (34.0 %) patients with two-vessel disease and in 12 (50.0 %) patients with three-vessel disease. In patients with a three-vessel lesion 50 % of patients had a negative test, in two-vessel lesion 21 (39.6 %) patients had a negative test, and in one-vessel lesion 30 (75.0 %) patients had a negative test.
All patients had a low threshold load-bearing capacity of 55.2±4.4 V before stenting. After stenting, there was a significant increase in the load-bearing capacity. Thus, in patients with single artery lesions, there was an average of 75.3±7.4 Vt, and in two-vessel patients — 69.6±4.6 VT (p<0.05). Patients with tricuspid lesions showed a decrease in threshold power and a mean of 62.8±5.6 VT (p<0.01). The results of the Bicycle Ergometer test showed a significant decrease in the number of patients with a positive Bicycle Ergometer test with an increase in the power of the tolerated load.
Thus, the analysis of the clinical and angiographic data showed that the main causes of clinical complications in the hospital treatment were acute stent thrombosis, lateral branch occlusion in bifurcation lesions and dissection at the end of the stent. According to the Bicycle Ergometer test, patients with CHD after myocardial revascularization have increased exercise bearing tolerance.
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