The Research On Effect Of Valve Prosthesis-patient Mismatch On The Long-term Survival Of Elderly Patients After Aortic Valve Replacement

ObjectiveAortic valve replacement (AVR) is a kind of operation using artificial valve to replace the original lesion or abnormal heart valve. It is a major treatment to cure aortic valve disease. Rheumatic heart disease as one of the common chronic heart disease still has a high incidence in recent years of our country, although the morbidity of it fells sharply. Due to the long time sequela of rheumatic, late appearing Clinical symptoms and the other reasons lead to patients go to a doctor later, thus will seriously affect the patient’s cure rate and quality of life for long time. Valve senile degeneration is a kind of natural aging process of the life, with the extension of global lifetime, the senile valve disease has a trend of increasing. It can make the valve calcification, disc ring expansion, disc lobes fusion and so on, caused the corresponding symptoms about aortic valve stenosis and/or aortic insufficiency. Also by aneurysms, coronary heart disease, infectious disease and other causes of valvular disease has a growing trend. Aortic valve lesions occupies the majority in senile valve disease, thus AVR is the first choice for treatment of the lesions. According to a report of domestic and overseas literature, after aortic valve replacement patients with artificial valves-mismatch (valve prosthesis-patient mismatch, PPM) become a common phenomenon. PPM refers to the effective orifice area of the placement artificial heart valve (the effective orifice area, EOA) is less than normal. It still has a series of postoperative complications or potentially dangerous situation due to the relatively narrow of aortic valve. The study of PPM after aortic and mitral valve replacement is more. According to the anatomy, physiology and pathology, the change of blood flow mechanics to analyze the impact on patients of PPM. After aortic valve replacement PPM can lead to high across valve pressure, no improvement of blood flow dynamics, the growth of left ventricular after load and the other factors that can affect cardiac function recovery, so to affect the long-term quality of life and survival. This study was to evaluate the effect of valve prosthesis-patient mismatch on the long-term survival of elderly patients after aortic valve replacement.Materials and methodsCollected the data of100patients(from July2000to July2005) over65years old who underwent simple aortic valve replacement or with concomitant coronary artery bypass grafting in the second hospital of Shandong university.The study included47males and53females, and the average age is69.3±4.8years old. Preoperative cardiac function NYHA grading demonstrated that33(33%)subjects were Ⅰ-Ⅱ grade,45(45%) grade Ⅲ,22(22%) grade Ⅳ. Operation with extracorporeal circulation(temperature36-28℃)under general anesthesia, 5cases through small incision of right subaxillary,3cases under the thoracoscope, the rest through the ascending aorta root by sternum midline incision for valve replacement. Among them,23patients (23%) had concomitant coronary artery bypass graft surgery.Refer to the EOA of manual valve and the patient’s body surface area (BSA) to calculate effective opening area index (EOAI). Accord to EOAI>1.0cm2 / m2defined no PPM,0.85<EOAI≤1.0cm2/m2as only mild PPM,0.65<EOAI<0.85cm2/m2as moderate PPM, EOAI<0.65cm2/m2as severe PPM. Divided the patients into matching group and mismatch group, mismatch group was divided into light, medium and severe group.Follow-up was carried out at the end of3rd month,6th month,1st year,3rd year,5th year and7th year and over post-operatively. Follow-up projects including general physical examination, routine blood tests, auxiliary examination, collecting the patient’s subjective intention through a questionnaire. Auxiliary examination includes UCG, chest X-ray and ECG. To obtain mean transprosthetic pressure gradient, flow rate, ejection fraction and estimation of valve electrocardiogram by via thoracic echocardiography measure. To evaluate comprehensively the cardiac function NYHA classification, mental health, and the patient’s long-term survival by clear up the data. Follow-up after operation is (7.2±3.6) years.ResultsThe survival rate at30th day post-operative between the two groups showed statistical difference, mismatching group was8.6%, Valves-matching group was3.3%. Long-term survival in the matching and mismatch group did not showed significant differences in the first0.5years to5years. Long-term survival after7years post-operatively revealed significant difference between the groups, especially those with severe mismatch group. Within1year and after5years post-operatively, the mean transprosthetic pressure gradient, ejection fraction of left ventricle revealed significant difference between groups, while intra-group difference was noticed in the severe mismatch group.ConclusionIn this study the rate of PPM was42%, the survival rate at30th day post-operative between the two groups showed significant difference, so PPM has significant effects for early mortality, which consistent with the literature at home and abroad. Long-term survival after7years post-operatively revealed significant difference between the groups, especially those with severe mismatch group. So we believed that severe PPM appears to influence the long-term survival rate after aortic valve replacement. After aortic valve replacement the MGP should be closed to zero. Severe PPM affects the long-term survival of patients through affecting the recovery of cardiac function. So we should use a variety of ways to prevent the occurrence of PPM in the largest extent.