Cardiogenic brain embolism (CBE) is a cerebrovascular embolism caused by cardiogenic emboli dislodged through the circulatory system, resulting in brain dysfunction in the associated blood supply area. According to statistics, about 1/4 of the emboli in cerebral embolism originate from the heart, of which heart valve disease is an important factor in its development. Due to its high rate of disability and death and the difficulty of clinical treatment, it is an important topic facing cardiac surgery. We performed heart valve replacement in 42 patients with CBE from June 1999.to October 2008 to summarize their surgical outcomes, timing of surgery, and perioperative management experience.
1. Data and Methods
1.1 Clinical Data
There were 42 cases in this group, 25 males and 17 females, aged 28-64 years, with an average age of 45.5 years and a disease duration of 0.5-30 years. There were 31 cases of rheumatic heart disease (20 cases of mitral stenosis or closure insufficiency, 7 cases of aortic stenosis or closure insufficiency, 4 cases of combined mitral and aortic valve lesions, 18 cases of combined tricuspid valve lesions, and 22 cases of left atrial thrombosis) and 11 cases of infective endocarditis (7 cases of mitral valve redundancy and 4 cases of aortic valve redundancy). There were 17 cases of NYHA class II, 19 cases of class III, and 6 cases of class IV; 10 cases of sinus rhythm, 32 cases of atrial fibrillation rhythm, and 4 cases with occasional premature ventricular beats. The cardiothoracic ratio ranged from 0.52 to 0.85. 42 patients had a clear history of cerebral embolism before surgery, including 5 cases with a history of 2 cerebral embolisms and 1 case with a history of 3 cerebral embolisms. The time between the complication of cerebral embolism and surgery ranged from 2 weeks to 9 years, including 8 cases with more than 1 year, 11 cases with 6 months to 1 year, and 23 cases with less than 6 months (including 3 cases with less than 1 month and 7 cases with 1~2 months). 35 patients still had sequelae of cerebral embolism at the time of admission, including 14 cases of left limb hemiparesis, 21 cases of right limb hemiparesis, 2 cases with consciousness disorder, and 18 cases with speech disorder.
1.2 Surgical method
The whole group underwent heart valve replacement under medium hypothermia and moderate hemodilution extracorporeal circulation, including mitral valve replacement in 27 cases, aortic valve replacement in 11 cases, combined mitral and aortic valve replacement in 4 cases, tricuspid valvuloplasty in 18 cases, and left atrial thrombus removal in 22 cases. The perfusion pressure was maintained at 60-80 mmHg in extracorporeal circulation to prevent drastic blood pressure fluctuations and high perfusion pressure.
1.3 Perioperative treatment
Preoperative cranial CT examination was routinely performed to determine the location, scope and size of the infarct foci and cerebral edema; echocardiography was performed to determine the heart valve condition and whether there was still left atrial thrombus or valve redundancy. Postoperatively, close observation of mental, pupillary and cardiac function status was performed, and respiratory care was strengthened. For those with psychoneurological symptoms, early determination of cerebral hemorrhage or embolism or only transient psychiatric symptoms should be made. For those with left atrial thrombus, anticoagulation should be performed as early as possible after surgery to prevent the formation of new thrombus on the rough trauma surface after thrombus removal.
1.4 Follow-up: All patients were followed up in the form of outpatient review, telephone and follow-up letters.
2. Results
2.1 Intraoperative situation
All patients in the group completed heart valve replacement and left atrial thrombus removal under extracorporeal circulation; 11 patients with infective endocarditis were cleared of valve redundancy, mainly loose masses ranging in size from 0.3 to 1.5 cm, 3 cases with infiltration of the annulus, and 3 cases with leaflet perforation; the redundancy was thoroughly cleared during surgery, and the infiltration was repeatedly applied with iodophor, rinsed with saline containing antimicrobial agent, and soaked in antimicrobial agent for mechanical valves after use.
2.2 Postoperative condition
The average postoperative hospital stay of the patients was 12.5 days. There were 4 deaths in the early postoperative period (within 30 days), with an operative mortality rate of 9.52%, and the causes of death were listed in Table 1 below, while the rest of the patients were discharged successfully.
There were 4 cases of postoperative non-fatal neuropsychiatric complications, the clinical manifestations and causes of which are shown in Table 2
There were 5 cases of postoperative pulmonary infections, 13 fiberoptic bronchoscopic aspirations, including 1 case of tracheotomy and 1 case of combined acute renal failure death, the rest were cured by treatment.
2.3 Follow-up results.
One case died of intracranial hemorrhage due to head injury more than one month after surgery, one case died of cerebral hemorrhage after three years, one case died of lung cancer after five years, two cases died of heart failure after six years, and the rest of the patients had good survival status.
3, Discussion
Heart valve disease is an important factor causing cerebral embolism, and many patients need valve replacement to improve cardiac function, and heart valve replacement under extracorporeal circulation after cerebral embolism can easily lead to cerebral re-embolism and bleeding, and various postoperative complications can easily occur, therefore, the selection of the timing of surgery and perioperative management for patients with CBE with heart valve disease has been a challenge for cardiac surgeons [5- 7].
3.1 Timing of surgery
It is the consensus of cardiac surgeons to decide the timing of surgery based on the degree of heart valve disease, the functional status of the heart, and the degree and recovery of cerebral embolism, but the clinical choice is still quite difficult. The healing process after cerebral embolism generally goes through an edema phase, absorption phase and scar phase, which generally takes 6-8 weeks. Therefore, to perform cardiac surgery, in principle, it is relatively safe only after 2 months after cerebral embolism, so as to try to avoid the aggravation of edema and bleeding in the cerebral infarction area, and also to avoid the generation of re-embolism. In our group, 32 cases were performed more than 2 months after cerebral embolism, but there were still 10 patients who underwent heart valve replacement within 2 months, accounting for 23.8%, among which 3 cases were due to acute heart failure with grade IV cardiac function and poor results of conservative medical treatment, 3 cases were cavernous infarction without significant sequelae, 4 cases were transient loss of consciousness or speech disorder, rapid recovery of limb hemiparesis, and significant reduction of infarct foci The infarct foci were significantly reduced. Two of these 10 patients died after surgery, one of them died from fisetin allergy, the other died from postoperative cerebral hemorrhage and brain herniation, and the rest recovered well. From the results, the risk of surgery within 2 months after cerebral embolism is within the acceptable range. Therefore, we believe that surgery can be arranged as early as possible after cerebral embolism in the following cases.
1.Acute heart failure with grade IV cardiac function and poor results of conservative medical treatment;
2.Small infarction foci, light hemiparesis, or rapid recovery from hemiparesis;
3.With left atrial thrombus or valvular valve redundancy, which may embolize again in the short term.
3.2 Perioperative management
Patients with hemiplegia, especially those with severe hemiplegia, should strengthen the limb function exercise and respiratory function exercise, and be given hyperbaric oxygen therapy if conditions permit; patients with left atrial thrombus, if surgery is not considered in the short term, can be treated with warfarin anticoagulation to prevent re-embolization. It has been reported in the literature that the incidence of cerebral hemorrhage in extracorporeal circulation is significantly higher after cerebral embolism. Therefore, avoid high perfusion pressure and obvious fluctuation of perfusion pressure in extracorporeal circulation, and also avoid excessive hemodilution to avoid cerebral hemorrhage or cerebral edema; the dosage of intraoperative heparin can be appropriately reduced for patients operated early after cerebral embolism to reduce the possibility of intracranial hemorrhage; the dosage of hormone should be appropriately increased to improve the stability of brain cell membrane and reduce the occurrence of cerebral edema; for suspected left atrial thrombus, the action should be gentle during the establishment of extracorporeal circulation The process should be gentle, avoid excessive extrusion of the heart, and avoid any operation on the left heart cavity before aortic block, such as insertion of left heart drainage tube, to prevent thrombus dislodgement. During the operation, the thrombus should be removed thoroughly, paying special attention to the heart ear as well as the pulmonary vein port and other places for any leftover thrombus, applying plenty of saline flushing, suturing the left heart ear closed in general, and in the case of huge left atrium, left atrial folding can be performed. In cases of infective endocarditis with valve redundancy, the redundancy should be completely removed; in cases of severe calcification of the valve or annulus, the calcified plaque should be removed as much as possible to avoid shedding of the calcified plaque.