Effects Of Myocardial Revascularization Research Articles

Treatment of ischemic heart disease in end-stage kidney disease patients on renal replacement therapy

This review paper aims to analyze the problem of diagnosis and treatment of coronary heart disease (CHD), also called ischemic heart disease (IHD), in patients with end-stage renal disease (ESRD). The analysis is based on current literature data. The issues of CHD risk stratification before patient listing for kidney transplantation (KT) and possible difficulties of diagnosing CHD using non-invasive examination methods in ESRD patients are considered. The effectiveness of myocardial revascularization and drug therapy, endovascular and surgical myocardial revascularization, is compared. The paper also discusses the peculiarities of drug therapy, particularly antiplatelet and antihyperlipidemic therapy in the treatment of CHD in dialysis-dependent patients and kidney recipients.

Effect of myocardial revascularization on the pathogenesis of postinfarction heart remodeling in elderly patients

Coronary heart disease from year to year remains the main cause of death in Russia. In Europe, about 1.8 million people die from various forms of coronary artery disease every year, and about 7.3 million people in the world. The main and most common form of coronary heart disease is myocardial infarction. More than 80% of myocardial in-farction-related deaths occur in elderly patients. Current-ly in Russia there is a clear trend of demographic aging of the population, which makes coronary heart disease and, in particular, myocardial infarction, an even more pressing problem. The course of myocardial infarction and postinfarction heart remodeling in elderly and senile patients is often severe, leading to most severe compli-cations (major adverse cardiovascular events) and death. The “gold standard” for combating the consequences of myocardial infarction is timely reperfusion of the com-promised coronary bed. Coronary artery bypass grafting is the most commonly used of all reperfusion methods, showing good long-term results in young patients. How-ever, in patients older than 60 years, the results of cor-onary artery bypass grafting are not so obvious, due to the presence of concomitant diseases and other factors that significantly complicate the postoperative course. In this regard, the study of the pathogenetic aspects of post-infarction remodeling and its reverse development after coronary bypass surgery in elderly and senile pa-tients is relevant. The question of the effect of coronary artery bypass grafting on preventing the development of potentially fatal complications of myocardial infarction remains open. That’s exactly what prompted us to write this article.

Arrhythmias in Patients after Surgical Myocardial Revascularization

This work represents literature review data regarding the study of the effect of surgical myocardial revascularization on the processes of electrical myocardial instability underlying the onset of life-threatening ventricular arrhythmias, as well as the possibilities for its non-invasive assessment by studying the heart rhythm variability and turbulence. Analyzed data demonstrated that, relying only on the presence of a viable myocardium, it is often impossible to predict the positive effect of revascularization on the prognosis in patients, especially those with reduced myocardial contractility. Considering the well-studied relationship between myocardial remodeling and neurohormonal activation, such non-invasive methods for assessing vegetative regulation of cardiac activity, as heart rate variability and turbulence may provide additional diagnostic information. The literature data indicate that heart failure, ventricular arrhythmias and recurrences of angina and myocardial infarction are the main problems that determine an unfavorable outcome in the postoperative period. There is important evidence that violations of the vegetative regulation of the heart, the heterogeneity of repolarization processes in the myocardium are integral indicators of the morphofunctional changes occurring in the process of coronary heart disease (CHD) progression. The role of indicators of heart rate variability and turbulence as predictors of sudden cardiac death was proved, mainly due to fatal ventricular heart rhythm disorders and cardiovascular mortality. Along with this, changes in these indicators, and their prognostic role in patients with CHD in revascularization are the subject of discussion, which determines the relevance of further studies on the effect of various methods of revascularization on the electrical instability of the myocardium, as one of the most important factors in the development of life-threatening ventricular arrhythmias that are predictors of sudden cardiac death, especially in patients who previously had acute myocardial infarction. Besides it is important to study the effect of myocardial revascularization on the indicators of cardiac autonomic regulation and the possibility of their use as prognostic criteria before and after surgery.

Вплив реваскуляризації міокарда на віддалений прогноз у пацієнтів із гострим коронарним синдромом та супутніми захворюваннями

Вплив реваскуляризації міокарда на віддалений прогноз у пацієнтів із гострим коронарним синдромом та супутніми захворюваннями

Ventricular Tachycardia Induced by Exercise Test as a Predictor of Coronary Artery Disease Development

A long-term clinical observation of the patient with ventricular tachycardia induced by exercise test but without myocardial ischemia and coronary artery atherosclerosis based on the results of angiography in the debut of the disease is described. However, arrhythmia reproducibility during stress tests, positive drug tests with nitroglycerin and beta-blocker, results of cardiac positron emission tomography with fatty acids revealed the ischemic genesis of arrhythmias, which was indirectly confirmed by a positive antiarrhythmic effect of the therapy with a metabolic drug (treatment with a beta-blocker was impossible because there was a sinus block). Coronary angiography was performed again after 7 years during the recurrence of ventricular arrhythmia with unstable angina. Stenosis of the left anterior descending artery was revealed. The antiarrhythmic effect of myocardial revascularization was continuously positive. Therefore, ventricular tachycardia induced by exercise test in patients with risk factors even in the absence of clinical and electrocardiographic criteria for myocardial ischemia could be an early debut of coronary artery disease.

THE ROLE OF MYOCARDIAL REVASCULARIZATION IN THE SURVIVAL OF PATIENTS WITH ALTERED CORONARY BLOOD FLOW DETECTED BY TRANSTHORACIC ULTRASOUND

Aim of the study was to identify the effects of myocardial revascularization on the prognosis in patients with altered coronary blood flow detected by transthoracic ultrasound.Material and Methods. Four hundred and twelve (412) patients were included in the study. The inclusion criterion was coronary velocity more than 70 cm/s during echocardiography. The study population was divided into three groups: Group 1 comprised patients with high velocities in the coronary arteries detected by ultrasound, in whom myocardial revascularization was performed; Group 2 comprised patients with high velocities in the coronary arteries, in whom myocardial revascularization was not performed and; the Control Group comprised patients with normal coronary blood flow according to ultrasound. The follow-up period was 10–11 months.Results. Seventeen (17) deaths (4.7%) occurred during follow-up. Death rates were 1.6 vs. 8.1 vs. 0% in Group 1, Group 2 and the Control Group, respectively, with a p-value for the difference between Group 1 and Group 2 (p1) of <0.009; and a p-value for the differences compared with the Control group (р2) of <0.03. Death, myocardial infarction, pulmonary edema, and acute coronary syndrome were observed in 27 patients (7.7% of the study group with accelerated blood flow). The rates of these outcomes were 4.9 vs. 11.0 vs. 0% in Group 1, Group 2, and the Control Group, respectively (p1<0.05; p2<0.006). Discussion. The study showed high rates of mortality or acute coronary events in the group of patients with pathologically high coronary flow velocities. The positive effects of revascularization on survival in this group were verified.Conclusions: 1. Left artery coronary flow velocities over 70 cm/s indicate a high probability of death or acute coronary events within 10.5 months.2. Myocardial revascularization has a significant positive effect on the survival rate and incidence of acute coronary events in patients with coronary artery flow velocities greater than 70 cm/s.3. Patients with high coronary blood flow velocities should be referred to coronary angiography or other diagnostic tests without waiting for clinical manifestations and specific symptoms for coronary artery disease.

EFFICACY OF MYOCARDIAL REVASCULARIZATION IN POTENTIAL RECIPIENTS OF HEART WITH THE CHRONIC ISCHEMIC HEART FAILURE

Aim: to evaluate clinical effi ciency of percutaneous coronary interventions (PCI) at potential recipients of heart with the chronic ischemic heart failure (CHF).Materials and methods. In this retrospective study results of treatment at 76 patients with CHF NYHA III and 36 patients with CHF NYHA IV by scheduled PCI are presented. Duration of observation was from 6 to 160 months. The age of patients at the time of intervention was 61,7 ± 0,62 years (from 33 to 76). 108 male and 4 female. Defi ned life expectancy and echocardiography parameters of the left ventricle (LV) of heart. Results.20 patients were died, 16 of them from cardiovascular events. 18 patients during this period undergo orthotopic heart transplantation (HT). The endovascular revascularization leads to LV volumes reduction, increase of ejection fraction and decrease of pulmonary artery pressure. Progress CHF is followed by negative dynamics of these characteristics and need of HT performance. In 74% of cases the effect of myocardial revascularization allows to provide increase in life expectancy of potential recipients of heart with the chronic ischemic heart failure. Conclusion.Performance of PCI at patients with the chronic ischemic heart failure can delay heart transplantation or become its alternative.

71 Effect of myocardial revascularization on left ventricular systolic function in patients with heart failure

71 Effect of myocardial revascularization on left ventricular systolic function in patients with heart failure

Diabetes Mellitus in Coronary Artery Surgery: Therapeutic Strategies in the Light of Recent Studies

Advances in percutaneous coronary revascularization have meant that, increasingly, patients with multivessel diseases are initially treated with the methods of interventional cardiology. Ongoing studies involving new stent coatings and optimized anti-thrombotic therapies could help to lower future restenosis rates and improve the success rate of stenting. Thrombocyte glycoprotein IIb/IIIa receptor blockers have already been shown to reduce the rate of acute PTCA complications in high-risk patients and could have a sustained impact on the long-term prognoses for PTCA patients. However, for diabetic patients with coronary multivessel diseases, coronary artery bypass grafting using arterial grafts as the initial revascularization method must be given preference over other therapy methods. Consequently, this group of patients is bound to grow in importance in cardiac surgery. The advances made in percutaneous coronary revascularization and in coronary surgery call for further prospective, controlled, randomized clinical studies in order to establish the best possible treatment strategy for patients with diabetes. It should be noted, however, that the therapeutic effect of myocardial revascularization is generally limited to individual coronary-arterial segments, whereas the pathological process of atherosclerosis is rather diffuse. The surgical strategy should therefore be seen as part of an overall strategy which encompasses other forms of treatment (e.g. intensive efforts to improve control of blood glucose level, blood pressure, and cholesterol level) in order to arrest the general progression of the disease and to reduce the risk of myocardial infarction and death.

The effect of myocardial surgical revascularization on left ventricular late potentials.

The presence of ventricular late potentials (LP) is an important indicator for the development of ventricular tachyarrhythmias due to ischemic heart disease. The effect of myocardial revascularization on LP has remained controversial. The purpose of this study was to determine whether complete myocardial surgical revascularization (CABG) documented by myocardial perfusion scintigraphy might alter the substrate responsible for LP. Prospectively, enrolled patients undergoing elective CABG were evaluated with thallium-201 myocardial perfusion scintigraphy and signal- averaged ECG pre- and postoperatively. SAECG recordings were obtained serially: before, 48-72 hours and 3 months after CABG. LPS were defined as positive if SAECG met at least two of Gomes criteria. Scintigraphies were performed pre- and 3 months postoperatively for determination of the success of revascularization. Changes observed in SAECG recordings after CABG were compared between those with and without successful revascularization. CABG resulted in successful revascularization in 23 patients and was unsuccessful in 17 (no change or deterioration of the perfusion defects). Preoperative SAECG values were not different between groups except for RMS values. The incidence of LP decreased significantly postoperatively in patients with improved myocardial perfusion, whereas there were no changes in patients who did not have postoperative perfusion improvement (McNemar test, P < 0.05). LPs disappear following the elimination of myocardial ischemia by complete surgical revascularization. Persistence of ischemia following CABG usually results in the persistence of late potentials. The incidence of ventricular arrhythmias is expected to be unchanged in these patients and they should be reevaluated for reinterventions.

Recovery of Left Ventricular Diastolic Function after Coronary Bypass Surgery

Effects of myocardial revascularization in patients with preoperative left ventricular diastolic dysfunction have not been well characterized. The aim of this study was to evaluate the recovery of diastolic function following successful coronary artery bypass surgery. Forty-five patients with normal diastolic function were selected for comparison with 45 patients who had a pattern of diastolic dysfunction. Mitral flow peak velocity ratios and atrial filling fractions were measured by pulsed Doppler echocardiography 24 hours before surgery. Diastolic dysfunction was defined as a mitral flow peak velocity ratio of less than one. After coronary artery bypass graft surgery, patients who required hemodynamic support were excluded from further study. Group 1 consisted of 38 patients (mean age, 59 ± 9 years) with normal preoperative peak velocity ratios. Group 2 consisted of 33 patients (mean age, 52 ± 9) with preoperative diastolic dysfunction. In group 1, mitral flow peak velocity ratios decreased immediately after cardiopulmonary bypass and persisted for 24 hours, returning to normal at 72 hours. In group 2, peak velocity ratios decreased immediately after cardiopulmonary bypass and persisted for 10 days. Similar changes occurred in atrial filling fractions in the 2 groups. These findings indicate that recovery of left ventricular diastolic function is prolonged in patients with preoperative dysfunction, which may reflect the time required for reversal of the effects of chronic myocardial ischemia.

Effect of myocardial revascularization and vein graft blood flow on pacing function

The effect of myocardial revascularization and vein graft blood flow on pacing function was determined in nine patients undergoing aortocoronary bypass. Pacing variables including threshold, current, and resistance were measured with a pacing system analyzer during intermittent pacing with a transluminal bipolar ventricular pacing probe. Pacing function was analyzed immediately before cardiopulmonary bypass (CPB) and compared with measurements taken eight minutes after full flow through the vein grafts had been established. Comparison of these two times showed a significant decrease in resistance, P < 0.003, and threshold, P < 0.03. After the second measurement, left anterior descending (n = 8), or right coronary (n = 1) vein graft blood flow was interrupted. Pacing variables were analyzed at one minute, two minutes, and four minutes following vein graft clamping; and a final set of measurements was obtained one minute following release of the vein graft clamp. Threshold increased but did not reach statistical significance. Resistance increased significantly: P < 0.03. All values returned to baseline following release of the vein graft clamp and full return of blood flow. The results of this study suggest that pacing function measurements are sensitive to changes in vein graft blood flow and may provide useful information about the condition of the myocardium, especially immediately prior to weaning from CPB.

Intraoperative evaluation of coronary bypass grafts by measuring myocardial blood flow using the electrolytic hydrogen clearance method.

The regional myocardial blood flow (MBF) was measured in 33 patients who underwent coronary bypass graft surgery in order to evaluate the efficiency of coronary bypass grafts in restoring MBF. MBF was measured by the electrolytic hydrogen clearance method during the coronary bypass surgery. The mean prebypass MBF was 161 +/- 19, 162 +/- 12, 80 +/- 12, 43 +/- 14, 104 +/- 18 ml/min/100 g in segments supplied by the left anterior descending coronary artery (LAD) showing less than or equal to 50 per cent, 75 per cent, 90 per cent, 99 per cent, and 100 per cent stenosis with collaterals, respectively. After bypass grafting of the LAD, the mean MBF increased from 70 +/- 13 and 126 +/- 12 ml/min/100 g to 133 +/- 14 and 163 +/- 9 ml/min/100 g in the segments with and without infarction, respectively. The mean postbypass MBF was 149 +/- 10 and 152 +/- 14 ml/min/100 g in the segments supplied by the LAD bypassed with saphenous vein grafts and mammary artery grafts, respectively. Postbypass MBF was dependent upon the magnitude of myocardial infarction. Measurement of MBF by the electrolytic hydrogen clearance method made it possible to quantitatively evaluate myocardial perfusion at the time of operation. It also provided direct information about the effectiveness of myocardial revascularization.

Hemodynamic effect of myocardial revascularization in the impaired ventricle

The hemodynamic effect of myocardial revascularization with saphenous vein grafts (mean 3.3 per patient) was analyzed 1 year after operation in 111 patients. Operations were performed using one continuous period of aortic cross-clamping with hyperkalemic cardioplegia for distal anastomoses in 84% of patients; 16% had arrest with topical and systemic hypothermia for myocardial protection. Group I (N = 18) had normal ventricles (ejection fraction [EF] greater than 50%; left ventricular end-diastolic pressure [LVEDP] less than or equal to 12 torr); Group II (N = 64) had ischemic ventricles (EF greater than 50%, LVEDP greater than 13 torr); and Group III (N = 30) had abnormal ventricles (EF less than 50%, LVEDP greater than 13 torr). Hemodynamic measurements were obtained before and 1 year after operation. Fifteen of 18 patients (83%) in Group I did not show significant hemodynamic changes, but in three EF decreased by greater than or equal to 10% and LVEDP increased by greater than 10% over preoperative levels. In Group II, EF was unchanged or slightly better in 89% (57/64) and worse in seven patients. Improvement in cardiac index (p less than 0.01) and LVEDP (p less than 0.001) was significant. Worsening of EF in 10 of 82 patients in Groups I and II was attributed to graft closure and/or poor myocardial protection. In Group III, significant improvement in cardiac index (p less than 0.001), EF (p less than 0.001), and LVEDP (p less than 0.01) was also noted. A subset of nine patients with EF less than or equal to 35% showed postoperative improvement in 56%. Of the remaining 20 patients with an EF of greater than 35% to less than 50%, half had greater than or equal to 20% improvement in postoperative EF. Operative mortality was 3.3% (1/30) for Group III. Late mortality was 1.5% (1/64) for Group II and 10% (3/29) for Group III. Significant improvement was noted postoperatively in 67% (57/85) of all patients who had preoperative treadmill tests (p less than 0.001). This study shows that myocardial revascularization significantly improved left ventricular performance in most patients with ischemic and abnormal ventricles. Previous studies that fail to show improvement may be related to incomplete revascularization and/or poor myocardial preservation. These data, therefore, justify the need for revascularization of the impaired ventricle.

Improvement in left ventricular function after myocardial revascularization Assessment by first-pass rest and exercise nuclear angiography

Thirty-six patients with coronary artery disease were studied by first-pass radionuclide angiography to assess the effects of myocardial revascularization on exercise-induced myocardial ischemia. The radionuclide studies were performed in the 30 degree right anterior ablique position, at rest and during exercise, 1 to 3 days preoperatively and 10 to 14 days postoperatively. The mean population age was 53 years; the mean number of grafts placed was 4.0 per patient. Fifteen normal male volunteers were tested by rest and exercise radionuclide angiography to serve as normal control subjects. In all exercise radionuclide studies, progressive upright bicycle exercise was performed to symptoms of fatigue, dyspnea, or chest pain. The parameters of ejection fraction (EF), end-diastolic volume (EDV), and regional wall motion (RWM) were determined. Twenty-nine of the 36 patients had postoperative coronary arteriography that was correlated with radionuclide determinations. The results showed that in the normal subjects with maximal exercise the mean EF rose, the mean EDV increased 19%, and there was no exercise-induced regional wall motion dysfunction (ERWMD). In the patients with coronary artery disease prior to operation, the mean EF fell significantly, the mean EDV rose 24%, and 26 of 36 patients had ERWMD. After operation, the mean EF of the group rose, the EDV increased only 15%, and only two of 36 patients continued to show ERWMD. Of the eight patients who demonstrated on abnormal response postoperatively, seven had what was considered to be inadequate revascularization, and in one there was no explanation. The data demonstrate that myocardial revascularization does improve ventricular function by abolishing exercise-induced evidence of ischemia (decreased EF, increased EDV, and ERWMD) as assessed by radionuclide angiography. Failure to abolish the exercise-induced functional instability suggests incomplete revascularization.

Acute Effects of Aortocoronary Bypass Surgery on Left Ventricular Function and Regional Myocardial Mechanics: A Clinical Study

The acute effects of myocardial revascularization on overall left ventricular performance and on myocardial segmental wall motion were assessed intraoperatively in 22 patients who had unstable (11 patients) or stable angina pectoris (11 patients). Segmental contraction patterns were evaluated using an ultrasonic transit-time method. In 9 patients with unstable angina pectoris, notable improvement in segmental wall motion was observed as the short-term response to coronary bypass grafting. Hypokinetic patterns were rendered normal after revascularization. Despite marked changes in segmental myocardial function, overall left ventricular performance was not altered notably. In contrast, reperfusion did not lead to acute effects on either segmental wall motion or total left ventricular function in patients with stable angina pectoris. The results indicate that aortocoronary bypass grafting may improve segmental wall motion in patients with unstable angina.

Selection of patients for direct myocardial revascularization.

AbstractThe high incidence of ischémic heart disease and its associated mortality, morbidity, and socioeconomic implications have stimulated a great deal of interest and controversy regarding the relative roles of surgical and medical therapy. There is general agreement that stable angina pectoris can be substantially improved or relieved by coronary artery bypass grafting in at least 80% of patients, and that stable angina not responding to medical treatment is a firm indication for this procedure if adequate distal vessels for grafting are present. The effect of myocardial revascularization on longevity in stable angina patients is not certain except in the presence of significant obstruction of the left main coronary artery, where improved prognosis has been demonstrated. Evidence appears to be accumulating that surgical treatment improves prognosis in disease involving 3 vessels and 2 vessels, particularly if reversible left ventricular dysfunction is present. The prognosis in single‐vessel coronary artery disease does not appear to be influenced by surgical therapy.Unstable angina pectoris appears to be best managed initially by intensive medical therapy and coronary angiography, with urgent surgery being done for significant left main coronary artery disease or uncontrolled angina, and elective surgery being done for multiple‐vessel disease. Coronary artery bypass grafting for acute myocardial infarction remains of limited value unless complications such as cardiogenic shock occur, when the prognosis may be somewhat improved by an early aggressive surgical approach in selected cases.Improved selection of patients for direct myocardial revascularization in the future appears to depend on the development and application of diagnostic methods that will quantify the relationship between coronary artery obstructive disease and myocardial function.

Effects of coronary bypass surgery on the electrical activity of revascularized myocardium Immediate and early postoperative observations

The effect of myocardial revascularization on bipolar epicardial electrograms was recorded with fixed wire electrodes from revascularized left ventricular sites and from control sites on the right ventricle. Studies were performed during and after surgery in 19 patients undergoing aorta-coronary bypass grafting for occlusive coronary artery disease and in 6 additional patients having aortic valve replacement for isolated aortic valve disease. In the latter 6 patients, neither left nor right ventricular electrogram voltage changed immediately following aortic valve replacement; however, left ventricular electrogram voltage gradually decreased for 5 days postoperatively. In the 19 patients with coronary artery disease, electrogram voltage in the revascularized area increased immediately following coronary bypass grafting (+40 to +300 per cent) in 13 patients (68 per cent) and immediately decreased (-20 to -70 per cent) in 6 patients (32 per cent). In 5 of the patients showing immediate increases, temporary occlusion of the bypass grafts for 3 minutes during surgery resulted in a decrease of electrogram voltage in the distribution of the occluded bypass, followed by return to preocclusion levels after release. Postoperative monitoring of electrogram voltage for 5 days in all patients with coronary artery disease revealed that the electrogram voltage in the revascularized area decreased to or below control levels in 16 patients (84 per cent) and remained increased in 3 patients (16 per cent). These observed changes did not correlate with preoperative hemodynamics, number of grafts, graft flow rate, aortic cross-clamp time, cardiopulmonary bypass time, and the early postoperative course. These preliminary observations suggest that coronary bypass grafting does affect the electrophysiological state of the revascularized myocardium. However, the mechanism by which it occurs and its clinical implications remain to be determined.

Ventricular function following experimental coronary artery bypass grafting: the relationship of functional improvement to haemodynamics in the graft.

The effects of myocardial revascularization were studied acutely in 13 dogs with chronic coronary artery occlusion. In nine animals an improvement in ventricular function was demonstrated following revascularization. Functional improvement was generally associated with high flow through the graft and low collateral flow.

Regional pathophysiologic effects of myocardial revascularization after acute coronary occlusion

Regional pathophysiologic effects of myocardial revascularization after acute coronary occlusion