In recent years, with the aging of the population and the improvement of medical conditions, the proportion of elderly patients in surgical patients is increasing, and the treatment of valvular disease in the elderly has become an important topic in valvular surgery, while aortic valve lesions in the elderly have their special characteristics in etiology and clinical management. From June 1996 to December 2006, we performed aortic valve replacement for 75 patients over 60 years of age, and the clinical characteristics of this group of cases are summarized as follows.
1. Clinical data
1.1 General information The diagnosis of 75 cases in this group was confirmed by clinical examination, X-ray, echocardiography, coronary angiography, etc. There were 52 male cases and 23 female cases; age ranged from 60 to 77 years old, with an average of 66.8 years old.
1.2 Preoperative lesions Degenerative lesions in 43 cases; rheumatic valve disease in 25 cases; bacterial endocarditis in 6 cases (including 2 cases of combined aortic valve diastasis, 2 cases of combined rheumatic valve disease, and 1 case of combined septal defect); syphilitic heart valve damage in 1 case. There were 5 cases of pure aortic stenosis, 24 cases of aortic valve insufficiency, and 46 cases of aortic valve stenosis with insufficiency. There were 28 cases of combined hypertension, 16 cases of diabetes mellitus, 10 cases of coronary atherosclerotic heart disease, 3 cases of tricuspid valve insufficiency, 2 cases of arteriovenous catheter insufficiency, 1 case of ventricular septal defect, 1 case of non-coronary sinus aneurysm, and 1 case of ascending aortic dilatation. Echocardiography showed an ejection fraction (EF) of 0.70 in 16 cases. NYHA classification: 3 cases of class I, 54 cases of class II-III, and 18 cases of class IV cardiac function.
1.3 Surgical method Under general anesthesia, moderate hypothermia, and extracorporeal circulation, myocardial protection was performed with the application of St. Thomas cold crystalloid stopping solution for paralleling perfusion in 5 cases, 4:1 blood-containing cold stopping solution for paralleling perfusion in 56 cases, blood-containing stopping solution for retrograde perfusion in 9 cases, and blood-containing stopping solution for paralleling plus retrograde perfusion in 5 cases.
All of them underwent aortic valve replacement, with 51 mechanical valves, including 27 St. Jude bilobed valves (including 8 HP valves and 2 RegentTM valves), 14 Sorin valves, and 10 Sorin supra-annular valves; 24 biological valves were used, including 22 Edwards Lifesciences valves and 2 Medtronic valves. During the same period, coronary artery bypass grafting was performed in 10 cases, including 3 cases of 1 branch, 6 cases of 2 branches, 1 case of 3 branches, 3 cases of tricuspid valvuloplasty, 2 cases of PDA suture closure, 1 case of ventricular septal defect repair, 1 case of coronary sinus aneurysm repair, and 1 case of partial artificial vessel replacement of the ascending aorta.
The duration of intraoperative extracorporeal circulation ranged from 59 to 245 min, with an average of 95.38 min, and the duration of aortic block ranged from 35 to 162 min, with an average of 66.8 min. 45 cases were automatically resuscitated, 30 cases were resuscitated by electric shock defibrillation, and one case was resuscitated after 5 times of electric shock defibrillation. All of them were given positive inotropic drugs to support the transition after resuscitation.
2. Results
There was no surgical death in the whole group. The main complications in the early postoperative period were: arrhythmia in 29 cases, low cardiac output in 5 cases, renal insufficiency in 10 cases, respiratory insufficiency in 5 cases, transient psychiatric symptoms in 2 cases, and re-entry into the chest to stop bleeding in 1 case. All complications improved after treatment. Postoperative follow-up was mainly through the outpatient clinic, and 9 cases were lost, with a follow-up rate of 88% and an average follow-up of 52 months (3-116 months), and all of the inner functions recovered to grade I-II at 6 months after discharge. There were three cases of late death, one case died of cerebral hemorrhage, one case died of malignant tumor, and one case died suddenly for unknown reasons.
3. Discussion
3.1 Etiology Although rheumatic heart disease is still the main cause of age-related valve disease in China, simple aortic valve damage caused by rheumatic fever is relatively rare. Among the 75 cases in this group, only 25 cases (33.3%) were due to rheumatic disease, while 43 cases (57.3%) were due to degenerative aortic valve lesions, showing that degenerative disease is the main cause of simple aortic valve lesions in the elderly. In addition, there are a few patients with bacterial endocarditis, but in this part of the cases, pure primary endocarditis is rare, and most of them are secondary infections based on the original cardiac lesions, which eventually lead to acute and severe aortic valve insufficiency, a common cause of death in valvular disease, which should be given sufficient attention. Among the six patients with aortic valve damage caused by infection, two cases had combined aortic valve diastasis, two cases had combined rheumatic valve disease, and one case had combined ventricular septal defect. According to our clinical data in recent years, there is an increasing trend of syphilitic cardiac macrovascular damage in patients, which needs to be recognized.
With the increasing refinement of valve surgery and coronary surgery techniques, valve replacement with coronary artery bypass has further reduced the operative mortality of elderly patients with combined coronary artery disease, provided that the coronary artery condition is clearly defined preoperatively. We routinely perform coronary angiography before direct intracardiac view in male patients over 50 years of age and in female patients over 55 years of age. In the case of this group of patients, this test is even more necessary because.
(1) Patients with severe aortic valve lesions can also present with myocardial ischemia, which has similarities in symptoms to coronary heart disease;
(2) The pathogenic factors of degenerative aortic valve lesions in the elderly are similar to those of atherosclerosis, and the pathogenesis of degenerative aortic valve lesions is generally considered to be atherosclerosis of the aortic valve;
(3) Asymptomatic or normal electrocardiogram in elderly patients does not exclude the possibility of combined coronary heart disease. In this group, there were 10 cases of combined coronary artery stenosis, accounting for 13.3%, which was significantly higher than the non-elderly valve disease group.
3.3 Selection of prosthetic valves The choice of prosthetic heart valves is still debated. We have applied 24 bioprosthetic valves to patients ≥65 years of age, and no cases of bioprosthetic valve failure have been found so far, but because of the small number of cases and the short follow-up period, the long-term results remain to be observed. In our group of 51 patients with mechanical valves, a total of 20 St. jude HP valves and the latest RegentTM and Sorin supra-annular valves were implanted, which we have experienced as a good solution to the problem of small aortic annulus, avoiding the need for annular expansion and greatly simplifying the procedure, especially in elderly patients. With the Sorin supra-annular valve, care should be taken when seating the prosthetic valve to avoid blocking the coronary artery opening and causing difficulties in reentry and decannulation.
3.4 Surgical and Perioperative Management Features
(1) Degenerative aortic valve disease in the elderly often involves significant calcification of the valve and annulus, and the calcified plaque often involves the aortic and subvalvular walls, the anterior mitral valve, and the septal membrane, so surgical excision of the valve and removal of the calcified plaque are key steps in surgery and need to be performed patiently and carefully, with care not to damage the septal membrane or the cardiac conduction bundle.
(2) The strength and elasticity of aortic tissues are poor in the elderly, so the aortic incision should be properly selected to 1.5 cm from the annulus to avoid the difficulty of hemostasis of the aortic incision if it is too low. Tension should be avoided when suturing the aortic incision, and for patients with dilated ascending aorta and thin aortic wall, we use 4-0 Prolene thread with continuous sutures on both sides of felt, which obviously reduces the occurrence of incisional bleeding.
(3) The cardiovascular system is less compliant in the elderly, and blood pressure should be strictly controlled in the early postoperative period, especially after awakening from anesthesia, medication and aspiration stimulation can cause rapid fluctuations in blood pressure, which can cause bleeding by tearing the suture site of the aortic wall with fragile tissue structure.
(4) timely management of arrhythmias, the incidence of arrhythmias in this group was 38.7% (29/75), which was significantly higher than that in the non-elderly group and non-aortic valve replacement group in the same period. We routinely left temporary epicardial pacing electrodes in case of unpredictability during the operation; postoperative attention to potassium and magnesium ion supplementation and blood gas adjustment, and the selection of appropriate antiarrhythmic drugs, minimized the harm caused by arrhythmias.
(5) Pay attention to the control of blood glucose, which needs to be monitored regularly after surgery to keep it at 6-9 mmol/L.