Selecting of statins optimum dosage regimen in patients with acute Q-wave myocardial infarction after thrombolytic therapy

Abstract

Cardiovascular diseases is the leading cause of death in the Ukraine in a nowadays. Despite the priority role of angioplasty in the treatment of acute Q-wave myocardial infarction, as demonstrated in recent clinical trials, in our country still actual urgent pharmacological recanalization of infarct-associated artery, that is thrombolytic therapy. However, during thrombolytic therapy in many cases fail to achieve optimal reperfusion of the myocardium, resulting in an active search for factors that increase the effectiveness of thrombolytic therapy, and medications that can improve the flow of Q-wave myocardial infarction. In this context, stabilization of atherosclerotic process is a priority after thrombolytic therapy in patients with acute Q-wave myocardial infarction. Pleotropic effects of statins allowed to justify the early administration of drugs in this group of patients after thrombolytic therapy, but there are some differences as to prescribe the dose that is appropriate in these conditions.

The aim of research: to study the effect of different dosing regimens of statins on clinical course, peculiarities of the aggregation and coagulation hemostasis, heart hemodynamics and incidence of complications in patients with acute Q-wave myocardial infarction after thrombolytic therapy.

Patients and methods.

The study involved 67 patients (43 men and 24 women), mean age - 64,5 ± 7,2 years, with a diagnosis of acute coronary syndrome with ST-segment elevation. All patients received thrombolytic therapy with streptokinase and basic therapy that included statins, anticoagulants, antiplatelet agents, beta-blockers, ACE inhibitors, nitrates. Depending on the dosage regimen of statins, patients were divided into groups: the first (18 people) - low-dose regimen (atorvastatin 20 mg/day or rosuvastatin 10 mg/day), second (27 people ) – medium-dose (atorvastatin 40 mg/day or rosuvastatin 20 mg/day), third ( 22 people ) – high-dose (atorvastatin 80 mg/day or rosuvastatin 40 mg/day). All patients were examined by clinical and laboratory methods, ECG and echocardiography on the fifth day and 6- minute walk test at the end of treatment (Day 14).

Statistical analysis of the results was performed on a personal computer using the licensed program "Statistica" (version 6.0, Stat Soft Inc, USA). The reliability performance differences were evaluated by Mann-Whitney and Wilcoxon, believed reliable differences at p < 0.05.

Results.

Clinical analysis in comparison with the first group in the second and third groups revealed significantly smaller quantity of anginal attacks per day, duration of anginal pain in the third group were significantly less patients with severe acute heart failure and ventricular arrhythmias. During the 6-minute walking test, patients of the third group underwent a longer distance than the first and second groups.

Study of coagulation hemostasis revealed that prothrombin in the third group is lower compared to the first and second groups as well as fibrinogen. Analyzing the platelets aggregation was clarified that the degree of aggregation in the first group was higher than in the second and third groups, the rate of aggregation was significantly higher in the first group than in the third, an the background of much less time of aggregation.

During the study of structural and functional parameters of the heart in the third group compared to the first and second significant advantage observed end-diastolic, end- systolic diameters and ejection fraction; in the second and third groups compared with the first group higher appeared stroke volume, stroke index, cardiac output and cardiac index.

In addition, the second and third groups compared with the first observed larger values of blood flow velocity during early diastolic filling of the left ventricle and the ratio of transmitral velocity of blood on the background of smaller values of blood flow velocity during atrial systole, deceleration time of transmitral blood flow and left ventricular isovolumic relaxation time, indicating a greater severity of violations of left ventricular diastolic function in the background of low-dose statin regimens.

Conclusions.

1. Patients receiving medium- and high-dose statin regimens have fewer clinical manifestations of coronary heart disease, the disease is easier, they have lower incidence of complications.

2. When using medium and high doses of statins decrease blood coagulation ability, at both the coagulation and hemostasis link aggregation.

3. In group of high-doses of statins in the subacute period of Q-wave myocardial infarction observed higher exercise tolerance against the backdrop of increasing the power of global LV systolic function.

4. The use of low-dose statin regimens accompanied by more severe violations of diastolic LV function.

Further studies of pathogenetic mechanisms and the clinical features of the course of acute Q-wave myocardial infarction left ventricular allow to identify possible ways of preventing life-threatening complications and optimize treatment tactics.