Patients with CKD have a significantly increased risk of coronary heart disease, not only because oftraditionally recognized CAD risk factors such as diabetes and hypertension, but also because of other non-traditionally recognized cardiovascular disease risk factors associated with uremia, including inflammation, oxidative stress, and abnormal calcium-phosphorus metabolism.Lipid metabolism disorders, mainly hypertriglyceridemia, are risk factors for coronary heart diseasein patients with CKD.This accounts for a prevalence of coronary heart disease of approximately 12% in patients with Stage 3 or greater CKD, compared with only 5% in those with normal renal function .CKD is often accompanied by disorders of mineral bone metabolism, hypocalcemia,hyperphosphatemia, and secondary hyperparathyroidism, all of which canaccelerate systemic atherosclerosis and vascular calcification .Inflammatory responses, oxidative stress, impaired endothelial cell function, coronary artery calcification, hyperhomocysteinemia, immunosuppression, and other mechanismscan contribute to significant acceleration of atherosclerosis, leading to a poor prognosis in this patient group.Complicationsof coronary heart disease, such as myocardial infarction and heart failure, are the main causes of death .Particularly in dialysis-dependent patients withadvanced CKD, the death rate is as high as 40%–50% .A 2012 epidemiological survey reported anincidence of CKD in mainland China of10.8% and estimated that there were 119.5 million patients withCKD in that country.Increasing numbers of thesepatients will require CABG in the future. There is an urgent need to improvepostoperative long-term survival rate.
In patients with severe coronary heart disease and non-dialysis-requiring CKD, CABG achieves significantly lowermortality, re-infarction, and revascularization rates than do PCI and drug therapy [12, 13].In one study 2108 patients with CKD who underwentPCI usingdrug-eluting stents, (n=1165) orCABG (n=943) were prospectively analyzed in a nonrandomized study with anaverage follow-up of 41.4 months.Although no significant differences in all-cause death, stroke, and myocardial infarction were observed between the two groups, the revascularization rate was significantly higher in the PCI group .A meta-analysis of 29,246 patients enrolled in 11 studies showed that CABG achievedlower long-term all-cause mortality, cardiac mortality, andincidences of myocardial infarction and revascularization, and fewer major adverse cardiacand cerebrovascular events (MACCE) than did drug-eluting stents forrevascularization in patients with multivesselcoronary heart disease and CKD. However, mortality and risk of cerebrovascular eventshaverecentlyincreased .Although CABG can significantly improve the survival rate, it also increases the incidence of postoperativerenal failure, especially in high-risk patients .
Off-pump CABG reportedly has a protective effect on renal function in the perioperative period because of it does not entailcardiopulmonary bypass; it also reduces the incidences of complications, such as allogeneic blood transfusion, post-operative thoracotomy hemostasis, acute kidney injury, and respiratory system dysfunction .However, in the CORONARY study, no significant difference was observedbetweenon-pump and off-pump CABGin effectson renal function at the 1 year follow-up, and off-pump had no demonstrable long-term renal protective effect . In the present study, there was a higher proportion of women, older mean age, and higher incidences of preoperative and postoperative complications in theCKD thanin the normal group.The follow-up period ranged from 1 to 9 years, with an average of 5.0±2.2 years.The incidences of stroke, myocardial infarction, and all-cause mortality were significantly higher in the CKD than in the normal renal function group; however, those of revascularization and heart failure were not.Logistic regression analysis showed that preoperative CKD was a risk factor for stroke, myocardial infarction, and all-cause mortality. After correctingfor common confounding factors such as sex, age, and LVEF, preoperative CKD was identified as a risk factor for myocardial infarction and all-cause mortality in the off-pump CABG over a mid- to long-term follow-up.
CKD and end-stage renal disease not only increase the risk of CAD, but also change its clinical manifestations and main symptoms.Management of patients with CAD and CKD is complexbecause of the possibility of complications and adverse effects during interventions.Protection of renal function and improvement in postoperative survival are criticalfor discharged patients with CKD not undergoing dialysiswho have undergone CABG.There is a need for cooperation among cardiac surgeons, cardiologists, nephrologists, and endocrinologists to enhance postoperative management and constructcomprehensive strategies, to improve prognosis and reduce complications and mortalityin high-risk patients.
First, the identification of high-risk patients facilitates rational allocation of medical resources, targeted prevention, and management.As renal function worsens,the length of hospital stay and medical costsand the number of complications increase.Decreasesin creatinine clearance to80, 60, and 20 mL/min reportedly lead to cost increases of 10%, 20%, and 30%, respectively.Additionally, the incidence of need for dialysis and mortality increase postoperatively.Grouping of CKD severity on the basis ofeGFR calculated by the CKD-EPI equation effectively predictspostoperative complications and mortality in both the short-and long-term . eGFRCKD-EPI<30 mL/min/1.73 m2, <41 mL/min/1.73 m2, <27 mL/min/1.73 m2, and <29 mL/min/1.73 m2 are predictors of early mortality, stroke, prolonged length of hospital stay, and postoperative dialysis substitution, respectively.Additionally, eGFRCKD-EPI <26mL/min/1.73 m2, <25mL/min/1.73 m2, <35mL/min/1.73 m2,and <29mL/min/1.73 m2are predictors of all-cause death, cardiovascular death, myocardial infarction, and heart failure,respectively, during follow-up (average follow-up time 66 months) .Therefore, the management of high-risk patients needs to be further strengthened.
Second, active treatment ofcomorbidities such as hypertension, diabetes, and anemia is vital.Hypertension and diabetes are the two commonestcomorbidities in patients with CKD.Recommendations for treatment of diabetic nephropathy include control of HB1Ac<7%, blood pressure <140/90 mmHg, and treatment with renin-angiotensin system blockers .Patients with CKD have a high incidence of hypertension that may lead to or originate from CKD.Hypertension aggravates CKD, resulting in uncontrollable hypertension .The 2017 American College of Cardiology/American Heart Association Hypertension Guidelines set a BP target of <130/80 mm Hg for patients with CKD and other strongcardiovascular risk factors toreduce mortality in patients with CKD. However, fewdata are available for patients with diabetes or Stage 4–5 CKD .Anemia, another common manifestation of renal insufficiency, causes decreased erythropoietin secretion and renal anemia.Anemia predicts the risk of cardiovascular events and death in patients with coronary heart disease .
Third, measures for secondary prevention of coronary heart disease should be actively continued postoperatively, including oral antiplatelet drugs, statin treatment, and good living habits.