Ischemic heart disease
Overview
Ischemic heart disease includes coronary artery obstruction or stenosis caused by atherosclerotic lesions. Myocardial ischemia resulting in left ventricular wall tumor, ventricular septal defect after myocardial embolism and mitral valve insufficiency due to papillary muscle ischemia are common and frequent acquired heart diseases in middle-aged and elderly people. This section focuses on atherosclerotic obstruction or stenosis of the coronary arteries. Atherosclerotic lesions of the coronary artery wall lead to narrowing of the lumen, obstruction of coronary blood flow, and inadequate blood supply to the myocardium, which can lead to myocardial infarction if the obstruction is severe. In the past 40 years, the incidence of coronary atherosclerotic heart disease has gradually increased in China. According to the statistics of Shanghai Medical University, coronary heart disease accounted for only 6% of inpatients with heart disease from 1948 to 1958; 18% from 1959 to 1971; and increased to 29% from 1972 to 1979, and now ranks first among all kinds of heart diseases. Xiao Shiliang, Department of Cardiac Surgery, Wuhan Union Medical College Hospital
【Treatment measures
The prevention and treatment methods of coronary heart disease can be summarized into two categories: medical and surgical. Internal treatment has a history of many years, and the treatment measures include adjusting diet and living habits, paying attention to mental health, applying drugs to reduce lipid content, inhibiting platelet aggregation and controlling angina pectoris. The surgical treatment of coronary artery disease has evolved in concept and method for more than 70 years. 1916 Jonnesco resected the cervical and thoracic sympathetic nerves to treat angina pectoris. 1926 Boas performed total thyroidectomy in an attempt to reduce the load on the ischemic myocardium by decreasing metabolism. 1935 Beck and Tichy performed a fixed suture between the pectoralis major and the myocardium in the hope that the adhesions formed would give the myocardium a better chance of survival. In 1935, Beck and Tichy performed fixation sutures of the pectoralis major and myocardium in the hope that the adhesions formed would supply blood to the myocardium. Since then, tissues and organs such as the pericardium, greater omentum, lung, jejunum, stomach, and spleen have been used for fixation sutures to the myocardium. In 1939, Zola, cesa-Bianchi ligated the internal thoracic artery bilaterally, believing that the proximal pericardial diaphragmatic artery could deliver more blood to the myocardium, and in 1946, Vineberg implanted the internal thoracic artery in the myocardium. In 1955, Beck advocated partial ligation of the venous sinus and partial ligation of the coronary sinus with coronary venous bypass of the arterial branches of the body circulation to perfuse the coronary circulation from the reverse direction. In 1958, Longmire et al. performed endothelial debridement of the diseased coronary artery to relieve luminal stenosis, and in 1961, Senning used graft sutures to enlarge the stenotic segment of the coronary artery under extracorporeal circulation. Gatrett performed a left anterior descending bypass graft using the saphenous vein, which remained patent for 7 years of follow-up. In 1967, Favaloro and Effler introduced the use of the saphenous vein for ascending aorta-coronary artery bypass grafting, and in 1969, they introduced the technique, and by 1971, 741 procedures had been performed. In 1971, Flemma et al. reported a sequential grafting procedure in which multiple anastomoses were made with a single saphenous vein and multiple branches of the coronary artery. Since then, the surgical treatment of coronary heart disease has entered a new stage. In 1979, grüntzig et al. reported that percutaneous transluminal intracoronary angioplasty is a relatively simple procedure that does not require open-heart surgery and is less costly, but the incidence of restenosis can be 30-40% in 6-9 months after surgery. In recent years, there are new equipment and techniques of percutaneous intracoronary coronary thrombolysis to treat myocardial infarction caused by early coronary embolism, and intracoronary cold laser to eliminate atherosclerotic plaque and stenotic lesions.
Since the causative factors of coronary atherosclerotic heart disease are complex and not yet fully understood, and there are many variations in the number and extent of lesions involving coronary artery branches, the speed of lesion development, and the harm caused to ventricular function, an in-depth comparison of the effects of medical and surgical treatment according to the natural course of various types of coronary heart disease is yet to be enriched by a long period of investigation and research. According to the existing clinical experience, although the surgical treatment of coronary artery disease cannot change or reverse the process of coronary atherosclerotic lesions, it can increase coronary blood flow and improve coronary circulation. After the ascending aorta-coronary artery bypass shunt with saphenous vein, the clinical follow-up data of a large number of cases show that the treatment is effective for angina pectoris, and the angina pectoris disappears in 60-95% of cases 1-5 years after the operation. The electrocardiogram returned to normal. 10 years after surgery, the number of cases in which angina disappeared due to graft vascular incompetence or progression of coronary artery disease decreased to 46%, while the rate of disappearance of angina in cases without surgical treatment was only 3%. Physical activity endurance improved significantly from 3 to 10 years after surgery compared to non-operated cases. Two years after surgery, 60% of the patients were able to perform their normal work, while only 26% of the cases treated medically returned to work.
Indications for surgical treatment of coronary artery atherosclerotic stenosis: ascending aorta-coronary artery bypass shunt with saphenous vein, commonly known as bypass surgery, is the most common surgical method for the surgical treatment of coronary artery disease.
1) Stable angina The factors affecting the development and prognosis of stable angina include: the number of coronary artery branches, especially whether the left coronary artery trunk or anterior descending branch is involved, the functional status of the left ventricle, the severity of myocardial ischemia, the patient’s gender and age, and whether there are other diseases. In cases of obstructive lesions in one or two coronary arteries that do not involve the left coronary artery trunk, the long-term efficacy of medical treatment is similar to that of surgical treatment, and it is advisable to start with medical treatment and regular review. However, if anti-anginal drugs such as nitrates, β-blockers and calcium antagonists fail to work in chronic stable angina, and the patient’s work and life are seriously affected, selective coronary angiography should be performed, and if the lumen area is reduced to more than 50%, especially if the lesion involves the left coronary artery trunk, the anterior descending branch of the left coronary artery or three branches of the coronary artery, surgery should be considered. The treatment should be considered.
Unstable angina The majority of cases have severe obstructive coronary artery lesions, and some cases have small subendocardial or scattered myocardial infarction, which may develop into acute myocardial infarction, severe arrhythmia or sudden death in a relatively short period of time. If angina is not controlled after 1 week of active medical treatment, selective coronary angiography should be performed and surgery should be performed as soon as possible according to the findings.
Those who support surgical treatment believe that surgical treatment within 8 hours after myocardial embolism can reduce the area of myocardial infarction, result in less myocardial scar tissue formation, lower complication rate of left ventricular wall tumor, arrhythmia, heart failure and sudden death after infarction, and more obvious improvement of left ventricular function. However, the surgical mortality rate of coronary artery bypass grafting in cases of acute myocardial infarction is high, and the incidence of postoperative pancreatic disease is also high, and follow-up data on long-term outcomes are yet to be completed. However, in cases with significant ST-segment depression on the active plate load test 2 weeks after myocardial infarction, the mortality rate at 1 year of follow-up is 13 times higher than that of negative tests, and surgery should be considered in such cases.
In recent years, treatments such as thrombolysis and percutaneous intracavitary coronary artery dilatation and angioplasty have been performed in cases of early myocardial embolism. The long-term efficacy of these therapies and their comparison with bypass grafting are still lacking sufficient information to draw conclusions.
4. In cases of severe ventricular arrhythmias, recovery from myocardial infarction or late presentation of severe ventricular arrhythmias, it is estimated that about 1/3 to 1/2 of sudden death occurs during the 2-3 years of follow-up. Therefore, myocardial ischemic ventricular arrhythmias should be considered as an indication for coronary artery bypass grafting.