| ObjectiveCoronary artery bypass grafting(CABG)is the standard treatment for three vessel lesions and left main artery lesions of coronary heart disease.Off-pump CABG(OPCAB)has become a routine surgical treatment of coronary heart disease in various heart centers in China because of its advantages of small trauma,no need for cardiopulmonary bypass,low early mortality and complication rate.However,obvious systemic inflammatory response and local myocardial ischemia can still be observed in patients after OPCAB.Its mechanism is not exactly the same as that of surgery under cardiopulmonary bypass,and is closely related to the adverse prognosis of patients.Therefore,early identification of patients at risk of poor prognosis after OPCAB surgery may help to adjust the treatment strategy during hospitalization.Prealbumin(PA),also known as transthyretin(TTR),is a rapid transporter synthesized by liver cells.Its main physiological function is to transport retinol,thyroxine T3 and T4.Compared with other serum proteins,prealbumin is not significantly affected by liver diseases and blood product infusion,and has short half-life and fast renewal rate,which is more sensitive than albumin.Under the pathological conditions of inflammation,stress and infection,the decrease of serum prealbumin level is closely related to the severity of a variety of diseases and complications after surgery.In clinical work,we found that there were also great differences in the early postoperative serum PA level of OPCAB patients,some only decreased slightly,some decreased significantly.Whether there is a certain relationship between PA and the occurrence and prognosis of postoperative complications has not been reported at home or abroad.Therefore,we conducted a large sample retrospective study to explore the relationship between prealbumin level and early complications of OPCAB and its predictive value.This study retrospectively collected the characteristic data of 1002 patients who completed elective OPCAB surgery in the Department of cardiac surgery of our hospital from January 2014 to July 2019.We collected the value of prealbumin in fasting venous blood samples within 6～12 hours after operation,discussed the relationship between the change of PA level and these prognostic indicators,and evaluated its predictive value.This study can help us identify patients at risk of poor prognosis early after operation,so as to guide perioperative treatment and timely adjust nursing strategies,which is helpful for patients’ postoperative recovery.Methods(1)Patients who underwent OPCAB surgery in cardiac surgery of Shandong Provincial Hospital from January 2014 to July 2019 were selected as the research object.The demographic and comorbidity,surgical factors,postoperative management,complications and clinical outcomes of all patients were collected.All patients stopped using antiplatelet drugs for 5～7 days before operation,and were treated with low molecular weight heparin during the period.All patients were scored with the EuroSCORE Ⅱ system before operation for cardiovascular operative risk evaluation.(2)All patients were treated with general anesthesia through oral endotracheal intubation.The operation was completed by the same surgeon.Off pump coronary artery bypass grafting was used.After thoracotomy through the median chest incision and the completion of bridge vessel anastomosis,the blood flow was measured and recorded by transit time flow measurement(TTFM).The blood flow waveform of bridge vessel was good and Pulsate Index≤5 was taken as the index of satisfactory blood flow.If necessary,it was necessary to bypass again.(3)After the operation,enter the extracardiac care unit.PaO2 is maintained between 80～120mmhg and PaCO2 is maintained between 35～45mmhg.The endotracheal intubation was removed when the patient had stable hemodynamics,no excessive bleeding(pericardial and mediastinal drainage for 3 hours<50ml/h),good spontaneous breathing and satisfactory oxygen partial pressure of blood gas analysis.The first fasting venous blood samples of all patients were collected within 6～12 hours after operation.Blood routine,myocardial enzymes and biochemical indexes were obtained and monitored every day.Maintain hemoglobin greater than 8g/dl and albumin greater than 35g/L,and timely deal with electrolyte imbalance to maintain the normal range.The systolic blood pressure of patients with invasive arterial pressure was maintained between 90～140mmHg with antihypertensive drugs or positive inotropic drugs.When the patient’s clinical condition tends to be stable,he is transferred from the intensive care unit to the general ward.(4)The collection of postoperative laboratory indexes was completed within 6～12h.According to the literature report,taking the most used 170mg/L as the dividing point,the patients were divided into two groups:Patients with PA<170mg/dL were classified as "low"PA group,and patients with PA≥170mg/L were classified as "normal" PA group.The main outcome measures were in-hospital mortality and postoperative complications,including pulmonary infection,pleural effusion,new onset atrial fibrillation(AF),liver function damage,cerebrovascular event(CVE),incision problems,respiratory failure,perioperative myocardial infarction(MI)Low left ventricular ejection fraction(LVEF)and acute renal failure(ARF)requiring hemodialysis.The secondary observation indexes were:postoperative extubation time,hospitalization time in intensive care unit,postoperative hospitalization time,use of positive inotropic drugs and application of intra-aortic balloon pump(IABP).(5)The Graphpad Prism 9.0 software was used for statistical analysis.The classified variables were expressed as the frequency and percentage of each group,and the chi-square test was used for difference analysis.The continuous variables were expressed as the median(25%～75%InterQuartile Range),and the Mann-Whitney nonparametric test was used for difference analysis.The baseline data and postoperative indexes between the two groups were compared.Spearman correlation coefficient is used for the correlation between continuous variables.P<0.05 is considered to have statistical difference,and P<0.001 has significant statistical difference.(6)Univariate logistic regression analysis was used to analyze the factors related to the main postoperative complications.Among them,the factors with predictive value entered the multivariate logistic regression analysis to eliminate the factors with confounding effect or interaction,clarify the predictive value of PA,and evaluate the predictive efficiency of PA by drawing the receiver operating characteristic(ROC).Results(1)Comparison of baseline data:there was no difference between the two groups in EuroSCORE II,demographic data,comorbidity,surgical data and preoperative cardiac function indexes(P>0.05).The preoperative albumin level of normal PA group was higher,42.1 vs 40.9(g/L),which was statistically significant,P<0.001,but the correlation analysis showed that the correlation between preoperative albumin level and albumin,body mass index and age was very weak.(2)Comparison of postoperative data:the length of stay in ICU,postoperative length of stay and extubation time in low PA group were significantly longer than those in normal PA group(P<0.001);The proportion of patients using positive inotropic drugs in low PA group was 26.94%,which was significantly higher than that in normal PA group;The number of neutrophils in low PA group within 6～12 hours after operation(×10 μg/L)was slightly higher than that in the normal group,12.78 vs 12.39(P=0.02),but this difference may be of little clinical significance.Overall incidence rate was high from low to low,followed by pulmonary infection(19.3%),new onset atrial fibrillation(17.1%),pleural effusion(10.1%),liver function impairment(6.3%),low LVEF(5.9%),perioperative myocardial infarction(3.2%),respiratory failure(1.5%),CVE(1.5%),incision problem(1.4%),hospital death(0.5%),ARF(0.3%)and IABP use(0.3%).The incidence of pulmonary infection(29.11%),pleural effusion(16.09%),new onset atrial fibrillation(23.87%),incision problems(2.35%)and respiratory failure(2.35%)in the low PA group were higher than those in the normal group.The most common postoperative complications were pulmonary infection and new onset atrial fibrillation.The higher incidence of pulmonary infection and new onset atrial fibrillation will be further analyzed.(3)The decrease of prealbumin level can be used as a risk factor for postoperative pulmonary infection(OR=0.977,95%CI:0.971-0.982,P<0.0001).Low PA level is associated with the increased incidence of pulmonary infection.Other risk factors include female,complicated with chronic lung disease,older age,longer operation time,longer extubation time.The results of multivariate logistic regression analysis showed that the decrease of prealbumin was an independent risk factor for postoperative pulmonary infection(Corrected OR=0.979,95%CI:0.973-0.985,P<0.0001).Other independent risk factors were age,operation time,postoperative extubation time,postoperative neutrophil level and preoperative albumin level.The results of ROC curve analysis showed that the preoperative albumin level had great predictive value for pulmonary infection(AUC=0.742,95%CI:0.704-0.781,P<0.0001),and the best cut-off value was 179.5(mg/L),and the efficiency of PA level combined with postoperative extubation time in predicting postoperative pulmonary infection was further improved.The decrease of prealbumin level was an independent risk factor for postoperative new onset atrial fibrillation(Corrected OR=0.985,95%CI:0.980-0.991,P<0.0001),and the ROC curve showed that the predictive value of low PA was better than that of age.Conclusions(1)Among patients with decreased prealbumin levels in the early stage after OPCAB,the risk of postoperative pulmonary infection,pleural effusion,incision problems,respiratory failure and other pulmonary complications and new onset atrial fibrillation is higher,and the use rate of positive inotropic drugs is higher during hospitalization.(2)Patients with decreased prealbumin levels in the early stage after OPCAB had longer extubation time,ICU hospitalization time and hospitalization time.(3)The early postoperative prealbumin level had no relationship with the preoperative nutritional status of patients.(4)The decrease of prealbumin level in the early postoperative period had no significant effect on the incidence of major cardiovascular and cerebrovascular events in patients with OPCAB.(5)Early postoperative prealbumin level is an independent predictor of postoperative pulmonary infection and new onset atrial fibrillation in patients with OPCAB.(6)The decrease of prealbumin level in the early stage after operation has high predictive value for postoperative pulmonary infection in OPCAB patients,and the best predictive cut-off value is 179.5g/L.(7)The prealbumin level after OPCAB has important has important predictive value for early major postoperative complications. |
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