Coronary intervention (PCI) has been widely used in the etiology of coronary heart disease due to its low invasiveness, reliable efficacy, low mortality and rapid postoperative recovery, and has yielded very good prognosis in the near and long term [1]. With the increase in the number of interventional cases, the difficulty of the procedure and the broadening of its popularity, the incidence of various surgical complications has gradually increased, and some of them even endanger patients’ lives, so it is very important to fully assess the patient’s systemic condition, intraoperative and postoperative risks and near and long-term prognosis before surgery.
Factors influencing intraoperative risk
Systemic factors The general systemic condition is closely related to the chance of various complications and risks occurring during surgery.
Age
Many studies have shown that the age of patients with coronary artery disease is closely related to the incidence and prognosis of various complications of surgery. It is generally believed that the incidence of various intraoperative and postoperative risks is significantly higher in the age group above 75 years old than in the age group below 75 years old, and the recovery of cardiac function and general condition after surgery is also slower and the prognosis is worse. Therefore, patients with coronary artery disease in the advanced age group above 80 years old should be treated with strict control of surgical indications, close observation of changes in condition, and timely management of various unexpected situations to improve the success rate of surgery and postoperative near and long-term survival rates and reduce mortality.
Cerebrovascular diseases
Cerebrovascular diseases, especially cerebral infarction, are common comorbidities in elderly patients, and careful preoperative examination is essential. if patients have symptoms of dizziness and transient ischemic attack, CT scan of the brain should be routinely performed, and the time of cerebral infarction should be carefully judged. antiplatelet and anticoagulation therapy should be cautiously performed for cerebral infarction within 3 months, and in principle, PCI therapy should be performed over 3 months, otherwise The incidence of cerebral hemorrhage is significantly increased. Patients with hypertensive disease with a history of more than 5-10 years should undergo cranial CT even if they have no neurological symptoms; the chance of cerebral infarction in such patients is high. Patients with blood pressure over 180/100 mmHg before and after surgery should undergo aggressive anti-hypertensive therapy to bring the blood pressure down to the desired target level as soon as possible; persistent hypertensive states are prone to intracranial hemorrhage. Patients with preoperative atrial fibrillation, when ultrasound shows left atrial thrombus or when cerebral embolism has already occurred, should pay close attention to the changes in postoperative neurological pathological signs and symptoms to prevent and treat cerebrovascular accidents. In general [4], the chance of severe stenosis in all 3 coronary arteries combined with the presence of cerebrovascular disease is 80-90%, so patients with severe coronary artery disease should pay more attention to the underlying cerebrovascular disease.
Pulmonary function status
Many patients, especially elderly patients with coronary artery disease, have pulmonary disorders, reduced pulmonary function or ventilation impairment that reduce the tolerability of surgery and the speed of postoperative recovery, increasing the incidence of complications and even sudden death [5]. Most patients with pulmonary artery pressure elevation due to pulmonary disorders, such as pulmonary heart disease, have peripheral edema and slowed venous blood flow, which predispose them to deep vein thrombosis and pulmonary embolism events. Therefore, postoperative encouragement of appropriate bedside exercise or appropriate lower extremity massage therapy can help prevent such malignant events when cardiac function permits. Most ischemic cardiomyopathies combined with cardiac insufficiency are associated with varying degrees of pulmonary infection, which can further decrease the ventilation/perfusion ratio and oxygen and dioxide diffusivity, leading to hypoxemia, slowing down the repair process and speed of myocardial ischemia-reperfusion injury, and delaying the patient’s recovery. Enhanced preoperative examination and preparation, and appropriate application of small amounts of cardiotonic, diuretic and vasodilator agents can help reduce the occurrence of adverse pulmonary factors.
Liver and kidney function status
Patients with hepatic and renal insufficiency have significantly higher rates of various intraoperative and postoperative complications and cardiovascular events than the average patient [6], and detailed preoperative examination of relevant indicators is very important. Patients with hepatic insufficiency are prone to hypoproteinemia, which will increase the chance of pulmonary edema and will further aggravate the degree of hepatic insufficiency when statins are then routinely administered, potentially inducing hepatic coma. Renal insufficiency is prone to sodium and water retention and uremia, which further increases the degree of cardiac pre and afterload and cardiac insufficiency and increases the chance of various accidents and acute left heart failure. Intraoperative isotonic contrast is used as much as possible and the dosage is strictly controlled; otherwise, cardiac and renal syndromes are prone to occur and increase the rate of cardiovascular events [6]. In patients with mild renal insufficiency or reduced compensatory capacity already present preoperatively, the appropriate addition of certain renal-preserving agents (e.g., the proprietary Chinese medicines renal failure nin or urotoxic clearing) is beneficial to reduce the incidence of various events and improve the survival rate of patients.
Other systemic conditions
Hematologic system disorders are highly insidious and can easily lead to misdiagnosis or missed diagnosis when patients have atypical symptoms [7]. However, patients with hematologic system disorders are prone to various bleeding events after antiplatelet and anticoagulation therapy, causing unexpected situations, so various laboratory indices should be read carefully before surgery, and bone marrow aspiration should be performed if necessary. Inflammation or ulceration of the digestive system is common and frequent and is prone to gastrointestinal bleeding during strong anticoagulation therapy, and many physicians use preoperative prophylactic administration of proton pump inhibitors to prevent gastrointestinal bleeding, but proton inhibitors can mildly reduce the pharmacological effects of antiplatelet agents such as clopidogrel, so it is crucial to enhance preoperative treatment in patients undergoing elective surgery to help reduce the aspirin and clopidogrel resistance incidence of aspirin and clopidogrel resistance [8]. In the event of bleeding, oral local treatment with norepinephrine in ice saline will have a good therapeutic effect, and it is not necessary to discontinue antiplatelet agents. The basic principle for patients with tumors, especially malignant tumors, combined with coronary artery disease is to take conservative drug treatment except for acute myocardial infarction, because patients with malignant tumors are in a state of varying degrees of hyperemia and have significantly reduced resistance, which makes it difficult for them to perform interventions. surgical treatment and long-term postoperative antiplatelet and anticoagulation therapy, which are prone to various bleeding complications, gastrointestinal reactions and suppressed state of hematopoietic system and shorten the life span of patients [4,6,8]. Recent, especially 3-month trauma and surgical patients, strong antiplatelet and anticoagulation therapy before, during, and after PCI predisposes patients to the risk of potential bleeding, so elective surgery patients are best deferred until 3 to 6 months later. Patients with urinary tract inflammation or tumors are not easily detected preoperatively, and postoperative anticoagulation measures can easily lead to microscopic or carnal hematuria, and relevant routine urine and ultrasound examinations should be enhanced to reduce the chance of occurrence.
Preoperative medication status
Patients who need to take medication for certain underlying disorders often have varying degrees of impairment of liver and kidney function, hematopoietic system, and general physical status, resulting in diminished compensatory function [9]. Patients with hyper- or hypothyroidism, diabetes mellitus and chronic hepatic and renal insufficiency require long-term drug therapy, and the drugs used have a certain impact on the coagulation system and the physical status, which can cause an increased incidence of certain accidents, and the preoperative testing of the relevant indicators should be strengthened.
1.2 Cardiovascular factors
Cardiovascular factors significantly influence the risk and prognosis of interventional procedures more than other factors, and are key factors in determining the success or failure of the procedure [10], which must be carefully evaluated preoperatively.
Blood pressure
Blood pressure status is a sensitive indicator of the stability of circulatory function. Patients with severe hypertension are at high risk of intracranial hemorrhage both intraoperatively and postoperatively, and once a bleeding event occurs it is not easy to stop the bleeding on the basis of antiplatelet agents, and the mortality rate is high even with craniotomy to stop the bleeding [11]. Persistent hypotensive state is a manifestation of low cardiac output or poor circulatory function, and such patients have poor tolerance for interventional procedures and are prone to sudden death intraoperatively and postoperatively. Preoperative cardiac function should be actively improved to maintain a normotensive state as much as possible, and vasoactive drug therapy should be applied appropriately if necessary to achieve intraoperative and postoperative safety as much as possible. The blood pressure fluctuates drastically, which means that the circulatory function is unstable, mostly due to emotional changes and internal environmental disturbances, and the incidence of intraoperative complications is increased, so the cause should be identified and appropriate countermeasures should be taken before surgery to keep the blood pressure in a stable state as much as possible, which is the key to reduce various unexpected complications.
Heart rate/rhythm
Heart rate abnormalities are in most cases a response to myocardial ischemia, damage, or cardiac function. A heart rate that is too fast or too slow is detrimental to the smooth recovery of the patient during and after surgery and increases the incidence of endpoint events [12]. A fast heart rate increases myocardial oxygen consumption and is detrimental to myocardial repair; a slow heart rate decreases cardiac output per minute, resulting in slower coronary and peripheral blood flow, which can lead to post-stent thrombosis when combined with increased blood viscosity or inadequate anticoagulation, so it is essential to ensure a stable heart rate during and after surgery. Arrhythmias, especially ventricular arrhythmias, are rarely caused by functional changes in the myocardium, but are mostly caused by myocardial damage, ischemia-reperfusion injury, metabolic changes, or myocardial and ventricular remodeling. Its main manifestations are frequent multi-source premature ventricular beats, short bursts of ventricular tachycardia or ventricular tachycardia, atrial fibrillation or atrioventricular block, sinus arrest or pathological sinus node syndrome, etc. Whichever arrhythmia is present must be taken seriously, otherwise the rate of cardiovascular events increases [13].
Cardiothoracic ratio
The normal cardiothoracic ratio of chest X-ray is around 0.5, which reflects both the size of the heart and a rough indication of lung capacity and ventilation, and is one of the effective indicators for simple determination of the basic cardiopulmonary status. After coronary revascularization, with the improvement of blood supply and metabolic level of myocardial cells, myocardial cells are gradually repaired, the heart gradually shrinks and the cardiothoracic ratio gradually returns to the normal level. In general, prolonged enlargement and non-recovery of the cardiothoracic ratio after hemodynamic reconstruction predicts a poor long-term prognosis for the patient, requiring careful analysis of the etiology and, if necessary, myocardial tissue engineering treatment [13]. Routine preoperative and postoperative chest plain films can also reveal some unexpected pulmonary disorders and pulmonary stasis conditions, which can help in the objective determination of cardiac function.
Cardiac ejection fraction (EF)
Non-invasive methods of cardiac ultrasound and nuclear myocardial scan can be used to obtain the relevant indicators of the systolic function of the heart. Normal is 50-55%, and a decrease indicates varying degrees of cardiac insufficiency. It is generally believed [14] that the lower the EF is, the less tolerable the surgery is. In principle, if the EF is lower than 20%-30%, pharmacological treatment should be given first to improve cardiac function before considering hemodynamic reconstruction treatment, otherwise the intraoperative and postoperative mortality rate increases. Clinical studies have shown that EF of 45% or more has a good tolerance for surgery and few postoperative complications; EF of 40%-45% has an average tolerance for surgery and postoperative complications are related to the level of observation and treatment; EF of 35%-40% has a poor tolerance for surgery and many postoperative complications; EF of 30%-35% has a very poor tolerance for surgery and many postoperative complications and prone to sudden death [15].
Short-axis shortening rate (FS )
The FS is better tolerated when the FS is >25%, but the opposite is true when the heart is not functioning well and the operative tolerance is reduced [15].
Cardiac chamber diameter
Left ventricular enlargement is mostly the result of ventricular remodeling after myocardial damage, which can lead to further reduction of cardiac function and form a vicious circle, leading to a gradual decrease in surgical tolerance and poor long-term prognosis. Right ventricular enlargement is usually the result of pulmonary hypertension and pulmonary disorders leading to a reduction in the vascular bed of the pulmonary circulation, and in a few cases, right ventricular infarction and tricuspid valve insufficiency or pulmonary valve stenosis/insufficiency leading to excessive anterior and posterior loads on the right ventricle. Therefore, attention should be paid to the prevention and treatment of such complications in the postoperative period [16].
Valvular status
Common valvular conditions in middle-aged and elderly patients are mitral, tricuspid, and aortic valve insufficiency, mostly as a corollary of cardiac enlargement, which can further increase the preload on the heart and lead to the development of intractable cardiac insufficiency. The key to treatment is to remove the cause, improve myocardial remodeling, reduce the anterior and posterior loads on the heart, and apply cardiac glycosides and diuretics appropriately to increase the tolerability and long-term prognosis of the procedure. Surgical valve replacement and bypass grafting should be considered in cases of unremarkable drug treatment combined with severe coronary lesions, otherwise mortality is high [7].
Pericardial disease
Pericardial effusions of varying degrees of severity due to various causes are commonly seen clinically. Pericardial effusion can further diminish cardiac ejection index and cardiac function and tolerance of surgery. Pericardial effusion due to cardiac insufficiency is most often seen in patients with right heart failure and total heart failure and is usually a small to moderate volume of effusion, with large volumes rarely occurring. In principle, these patients have a very poor tolerance for surgery and should first address the primary disease of the pericardium and then consider hemodynamic reconstruction [9].
Peripheral vascular disease
Peripheral vascular diseases in patients with coronary artery disease are mostly multiple aortitis and deep venous valve disorders, both of which are prone to thrombotic complications and sudden death. Therefore, timely and effective long-term antiplatelet agents and anticoagulation therapy are essential to reduce such complications.
1, 3 Coronary interventional procedure factors
The degree of coronary lesion and the time factor are key factors and determinants of the success or failure of the procedure, so it is extremely important to fully understand the characteristics and nature of the lesion [3,6].
Coronary lesion site
Luminal stenosis or occlusion due to coronary atherosclerosis is mainly detected by coronary angiography (CAG) or coronary dual-source 128-320-row angiography. The site of the lesion is directly related to the risk level of the patient’s condition. In general, lesions in the left main trunk (LM) of the coronary artery, the LM bifurcation and the opening and proximal segment of the anterior descending branch (LAD) and the gyrus (CX), and lesions in the proximal segment of the opening of the right coronary (RCA) have a wide range of myocardial damage or necrosis and a high impact on cardiac function, with an increased chance of malignant arrhythmia, acute left heart failure and sudden death, so preoperative Therefore, we should actively and carefully prepare, closely observe and treat intraoperatively and postoperatively, and make detailed surgical plans to thoroughly prevent various unexpected situations and events. The chances of thrombosis after stenting of bifurcation lesions are significantly higher than in general patients [10].
Degree of coronary lesion
The degree of risk of coronary revascularization is directly related to the degree of stenosis, i.e., the greater the degree of stenosis the greater the risk. In general [4,7,15], patients with stenosis close to 99% of the lesion wire passed after interruption of blood flow are prone to serious intraoperative complications and even sudden death. Acute complete occlusive lesions with myocardium undergoing acute necrosis circulatory function is in an unstable state and the rate of cardiovascular events is significantly increased. The risk level of chronic total occlusive lesions (CTO) is related to the site of coronary occlusion and the formation of collateral circulation, and those with proximal occlusion and no collateral circulation formation have a large extent of myocardial necrosis and a high risk.
Nature of coronary lesions
Coronary lesions determine the softness of plaque lesions and the ease of wire passage and the smoothness of surgical treatment. In general, the longer the stenosis or occlusion, the harder the lesion, the less easy it is for the wire to pass through the lesion; the more calcified the lesion, especially the degree of intimal calcification, the more difficult it is for the wire to pass and the balloon to pre-dilate; when the calcified hardness of the lesion exceeds the hardness of the wire, the wire cannot pass through the lesion. In this case, the transendovascular subendovascular STAR technique can be used to bypass the extremely hard lesion area so that the wire can reach the true lumen of the distal vessel and improve the success rate of the procedure after dilatation and stent placement [5,8].
Extent of coronary lesions
The number of vessels with coronary stenosis correlates linearly with the extent of myocardial ischemia and, of course, with the site of stenosis. The number of occluded vessels is also linearly correlated with the extent of myocardial necrosis, i.e., the closer the vessel occlusion is to the end, the greater the number of occluded vessels, the greater the extent of myocardial necrosis, the lower the compensatory capacity of the heart, the greater the degree of cardiac insufficiency, the less tolerable the procedure, the higher the chance of intraoperative and postoperative complications, and the increased rate of sudden death.
Interventional procedures
The ease of the procedure and the surgical approach and method are closely related to the rate of intraoperative and postoperative complications and events in patients. In general, patients with severe LM+ anterior trigeminal lesions, RCA/LAD/LCX proximal segments and open-ended lesions have significantly higher incident rates than patients with other site lesion interventions, regardless of the surgical approach. Long lesions, angular lesions, bifurcation lesions and slow flow rates have a high incidence of postoperative in-stent thrombosis, and postoperative 3-part antiplatelet therapy should be intensified and the duration of anticoagulation therapy should be extended appropriately to reduce the incidence of various untoward events. Stent-vessel diameter mismatch, insufficient dilation pressure and dilation time are common causes of in-stent thrombosis, so fine surgical operation, especially high-pressure post-balloon dilation technique, is another key to reduce complications and improve long-term prognosis. Incomplete stent coverage of the target lesion is one of the main etiologies of restenosis at both ends of the stent in the distant future. Regardless of the double stenting technique used in bifurcation lesions, the final double balloon anastomosis expansion technique is one of the main measures to reduce in-stent thrombosis and distant restenosis. Intravascular ultrasound techniques (IVUS) and intravascular optical imaging (OCT), applied in recent years, are great guides for detecting the nature of plaque and stent apposition, and are reliable methods for reducing many malignant events intraoperatively and postoperatively [15].
Surgical emergency measures
Many malignant events and even sudden deaths can be turned around if resuscitation measures and methods are appropriate, unfortunately many emergency measures and methods in catheterization laboratories are at a very general level and do not correspond to the requirements of the critically ill patients being treated, resulting in many very regrettable events. Resuscitation of surgical patients requires a clear concept, correct measures, appropriate methods, promptness, and the availability of medication and equipment.
Equipment and apparatus preparation
Mainly electrocardiographic monitors, defibrillators, blood pressure, heart rate, heart rhythm and oxygen saturation monitoring devices, temporary pacemakers and electrodes, color ultrasound and aortic balloon counterpulsation pump (IBP) and other devices should be in place in time to be able to quickly detect various abnormalities and deal with them in time to significantly reduce the incidence of cardiovascular events. In particular, IBP is extremely important to ensure priority coronary blood supply and stabilize circulating blood pressure during interventions for patients with severe cardiac insufficiency.