RU2292855C2 - Method for treating ischemic cardiac disease - Google Patents

Abstract

FIELD: medicine, cardiosurgery.

SUBSTANCE: the present innovation deals with applying lasers for treating ischemic cardiac disease due to laser myocardial revascularization. It is necessary to fulfill through canals in myocardium upon open active heart due to laser radiation. Moreover, the development of multiple transmyocardial canals of 0.5-1.0 mm diameter should be carried out with radiation of a powerful impulse wave-guide CO₂-laser at wave length being 10.6 mcm at peak power of about 500-700 W and duration of impulse radiation being 23-35 msec. Moreover, the impulse should be supplied onto myocardium at developing every canal at the moment that corresponds to the onset of ST segment of patient's electrocardiogram. The innovation enables to decrease the risk for the development of cardiac rhythm disorders and complications, considerably decrease intrasurgical period and provide long-term positive effect, moreover, it is possible to observe the recovery and prolonged circulation supply of ischemized myocardial parts.

EFFECT: higher efficiency of therapy.

1 ex, 1 tbl

Description

The claimed invention relates to medicine, in particular to the use of lasers in cardiac surgery, and can be used to treat coronary heart disease by laser myocardial revascularization.

Coronary heart disease - deterioration in the blood supply to the muscles of the left ventricle (myocardium) is a widespread disease leading to disability or death of patients. For its treatment, in case of ineffective use of medicinal methods, coronary artery bypass grafting and angioplasty are used. However, there are categories of patients for whom it is impossible to revascularize the myocardium by such methods (Yu.V. Belov. Thoracic and cardiovascular surgery, 1992, No. 1-2, pp. 5-8). Recently, methods of laser myocardial revascularization have become widespread in clinical practice. In particular, compared with aorto-coronary artery bypass grafting, laser myocardial revascularization can be performed on a working heart without the use of a cardiopulmonary bypass.

As an analogue, a method of laser myocardial revascularization is known, when in the thickness of the heart muscle of the left ventricle using laser radiation with an energy of up to 20 J with a pulse duration of 80-100 ms, channels with a diameter of 200-280 microns are created, opening into the heart cavity (O.K. Skobelkin Lasers in surgery. M., "Medicine", 1989, S. 230-238). However, this method provides only a short-term positive effect; over time, the formed channels are overgrown with granulating tissue, which, accordingly, reduces the blood supply to ischemic areas of the heart.

A known method of treating coronary heart disease (prototype) according to the patent of the Russian Federation No. 2075963 from 11.11.94, (published on 03/27/97). In the prototype, it is proposed to treat coronary heart disease by creating through channels in the myocardium with a diameter of 1.0-2.0 mm using laser radiation with a wavelength of 1.06 μm at an exposure time for the formation of one channel of 0.5-1.5 s. For this, the end of the fiber through which the radiation is delivered to the myocardium is mounted on its outer surface (epicardium); then produce laser exposure. After its completion, the inlet of the channel is sutured. As a result of such an impact, a channel is created which is subsequently preserved and whose walls are close in structure to the walls of a normal vessel, i.e. a new bloodstream is being formed, which also stimulates the development of blood supply due to previously non-functioning capillaries.

The disadvantages of the prototype include:

1) significant damage to the myocardium in the place of direct contact with the fiber, the need to suture the inlet of the channel;

2) the time of laser exposure when creating one channel (from 0.5 s to 1.5 s) exceeds the time of the cardiac cycle (0.15 s), which increases the risk of heart rhythm disturbances, leading to great myocardial trauma;

3) there is the possibility of uncontrolled overgrowth of newly formed vessels, which over time leads to a decrease in blood supply to the ischemic myocardial site; specific data on the durability of the positive effect of such laser revascularization in the prototype is missing;

4) prolonged laser exposure to the myocardium, the need to suture the inlet of the laser channels increases the intraoperative period, which is fraught with cooling the patient, leading to an increase in the total peripheral resistance to the working heart. This increases the period of the resuscitation period, negatively affects the hemodynamics and postoperative condition of the patient.

Common features of the claimed invention and prototype: the implementation of the channels in the myocardium on an open working heart using laser radiation.

The aim of the invention is to provide a method for the treatment of coronary heart disease by laser myocardial revascularization with minimal damage to the myocardium, reducing the risk of heart rhythm disturbances and complications, significantly reducing the intraoperative period, providing a long-term positive effect.

The essence of the claimed invention lies in the fact that the method of treating coronary heart disease involves performing through channels in the myocardium on an open working heart using laser radiation, characterized in that the creation of multiple transmyocardial channels with a diameter of 0.5-1.0 mm is produced by the radiation of a powerful pulsed waveguide CO ₂ laser with a wavelength of 10.6 microns and the peak power of 500-700 W and a pulse duration of 25-35 milliseconds supplied to the myocardium to create in each channel time corresponding Achal ST segment of the electrocardiogram of the patient.

When the set of the above conditions is met, there is a restoration and long-term blood supply to the ischemic sections of the myocardium, the possibility of heart rhythm disturbances is excluded, the duration of the operation and the postoperative period are reduced, and the risk of postoperative complications is reduced.

A powerful pulsed waveguide CO ₂ laser with a wavelength of 10.6 μm is used as a radiation source, characterized by high radiation quality and low angular divergence (1.5 mrad). The radiation of such a laser transmitted through an optical manipulator and focused by a lens on the myocardium surface allows creating through channels with a diameter of 0.5-1.0 mm per pulse. Peak radiation power of less than 500 W is not enough for the formation of a through channel, and at more than 700 W the necrosis zone, channel size and, accordingly, the degree of myocardial trauma increase. The choice of the range of laser pulse durations of 25-35 ms and the moment of applying the pulse to the myocardium are due to the following. A pulse duration of less than 25 ms is not enough to create a through channel in the myocardium, and with a duration of more than 35 ms, the risk of heart rhythm disturbances and damage to the internal structures of the heart increases. With such durations of exposure to radiation, the creation time of one channel, compared with the prototype, is reduced by 20-45 times. Laser exposure to the myocardium is performed at the time of filling the left ventricle of the heart with maximum blood. This corresponds in time to the ST segment (after the end of the QRS complex and before the start of the T wave) of the patient’s electrocardiogram and is 29-36 ms (V.N. Orlov. Guide to electrocardiography. M., "Medicine", 1984, p. 73-79 ) The claimed range of laser pulse durations does not exceed the specified time interval, therefore, the risk of heart rhythm disturbances is excluded.

At the indicated intervals and the totality of the parameters of the laser action, overgrowth of the channels proceeds over time, and new capillaries form in the radiation transmission region and near the previously created channel. The subjective state of patients improves several days after laser myocardial revascularization and after 3 months in all 100% of patients it is good or excellent. Improvement of the functional state and blood supply of the myocardium reaches its maximum 12 months after the operation and continued or continued to improve in the subsequent observation period (up to 3 years). When creating a channel with a diameter of less than 0.5 mm, there is no initiation of the growth of new capillaries, and with a diameter of more than 1.0 mm, the degree of myocardial trauma sharply increases. Also, with such dimensions of the channel there is no need to suture its inlet, which reduces the time of the operation.

The effect of the claimed method for the treatment of coronary heart disease is as follows: the terms of the intraoperative period are reduced; there is no risk of heart rhythm disturbance and hemodynamic impairment; the intensity and duration of angina attacks decreases sharply; the maximum intake of nitroglycerin is significantly reduced (from 60 tablets / day to 2 tablets / day); the patient’s motor mode is significantly expanded (from 500 m before surgery to 4-6 km after).

95 patients were operated on using this method (average age 55.6 ± 1.5 years, average duration of coronary heart disease 68.0 ± 13.1 months, had myocardial infarction 76.2%, average functional class (FC) 3.9) . There were no significant postoperative complications. A positive effect was achieved in all patients in the observation period up to 3 years.

EXAMPLE OF SPECIFIC PERFORMANCE

Patient K., 55 years old, duration of coronary heart disease 7 years, 4th functional class (FC), suffered acute myocardial infarction 3 months before admission, average intake of nitroglycerin 46 tablets / day. With the help of coronography and echocardiography, the degree of viability and localization of myocardial damage was established. The operation was performed on a working heart under combined endotracheal anesthesia. A mandatory step was an audit of the degree of myocardial damage in order to make a final decision on the areas of myocardial revascularization. After the optical manipulator was located above the surface of the left ventricle of the heart at a time corresponding to the beginning of the ST segment of the patient’s electrocardiogram, a laser pulse of 30 ms duration was applied at a peak radiation power of 600 W. Completed 42 through channels with a diameter of 1.0 mm along the front and side surfaces of the left ventricle of the heart. The channels were controlled by echocardiography. After the operation, active drainage was established in the pleural cavity and the chest was sutured according to the standard method. Heart rhythm disturbances and complications were not observed (see table).

Postoperative data: parameter 3 month 6 months 1 year 3 years FC (function class) 3.0 2.1 1.4 0.6 The average intake of nitroglycerin (table / day) 22 10 3 -

When conducting an analysis of the literature and the patent situation, no similar method of treating coronary heart disease was found, on the basis of which we can conclude that the claimed invention meets the criteria of "novelty", "inventive step", "industrial applicability".

Claims (1)

A method of treating coronary heart disease, including performing through channels in the myocardium on an open working heart using laser radiation, characterized in that the creation of multiple transmyocardial channels with a diameter of 0.5-1.0 mm is produced by radiation of a powerful pulsed waveguide CO ₂ laser with a wavelength 10.6 μm with a peak power of 500-700 W and a pulse duration of 25-35 ms transmitted to the myocardium during the creation of each channel at a time corresponding to the beginning of the ST segment of the patient's electrocardiogram.