Clinical Feature and Outcome of Angiographic Coronary Artery Disease in Chronic Kidney Disease Patients

The prevalence and mortality rate of cardiovascular disease (CVD) in chronic kidney disease (CKD) patients is high. The prevalence of coronary artery disease (CAD) in CKD population ranges from 38 to 65%, with an average of 3.3 coronary lesions per person. The relative risk for death from myocardial infarction and CAD is 1.18 in CKD patients with GFR \< 60 ml/min. Because of this high prevalence of CAD and its high mortality, reducing and preventing CAD risk factors is crucial in the clinical management of CKD patients.

Low glomerular filtration rate (GFR) constitutes an important independent risk factor for CAD. Several pathogenic factors play role in the genesis of cardiovascular dysfunction in chronic kidney disease. Increased traditional CAD risk factor, endothelial dysfunction, sympathetic hyperactivity, renin-angiotensin system activation, increased glycosylated end products, all contribute to the characteristic medial calcification of cardiovascular disease in CKD patients. Hypertension, fluid overloading and anemia further aggravated the cardiac loading, leading to myocardial hypertrophy with chamber dilatation, heart failure and death.

The mortality rate of CAD in CKD patients is extremely high. The NHANES II (National Health and Nutritional Evaluation Survey) found an increased of mortality rate\> 51%, when the GFR decreased from \> 90 to \< 70 ml/min. The 1-year mortality rate in different CKD stage were 0.7% (normal renal function patients), 2.0% (patients with proteinuria), 3.5% (overt proteinuric patients) and 12.1% (dialysis patients), respectively. However, the clinical feature and outcome of CAD in different stage of CKD remains unclear.

We conducted a retrospective cohort study involving all patients admitted for coronary angiography from 1992 to 2004. The patients were categorized into five stages of CAD to compare the risk factor, clinical feature and outcome. Determination of this relationship can help to establish factors for early detection of CAD in CKD patients and also prognostic factor to improve outcome of these patients.

All patients who underwent cardiac catheterization for assessment of CAD at Keelung Chang Gung Memorial Hospital between 1992 and 2004 with continuous serum creatinine values measured before admission were included in this analysis. Data were obtained from medical records of the database center of our institution. Demographic and clinical data were assessed. The age, sex, body mass index (BMI), body surface area (BSA), underlying comorbidities, CAD risk factors (including diabetes mellitus, hypertension, dyslipidemia, smoking, and obesity, defined as a BMI \> 30) and clinical presentation were included in this study. Hemodynamic parameters including the systolic and diastolic blood pressure, heart rate and left ventricular ejection fraction were also obtained. Coronary angiography was performed using a low-osmolarity non-ionic contrast medium (iodixanol) by experienced cardiologist. Coronary artery disease was defined as a 50% or greater lumen narrowing of a major epicardial artery or its branches. A left main stenosis of 50% or greater was regarded as equivalent to 2-vessel disease. Blood samples were collected during admission before angiographic procedure. Values of hemoglobin, white blood cells, platelet, high sensitivity C-reactive protein (hs-CRP) and troponin I was included. The treatment modality was divided into three categories: medical, percutaneous coronary intervention (PCI, including balloon angioplasty with or without stent placement) and coronary artery bridge graft (CABG) on the basis of clinical condition and angiographic finding. The outcome was followed-up until 12 months after angiographic procedure. The estimated total study patient number is approximately 1000 patients.

Eligibility Criteria:
Inclusion Criteria:

1. CKD patients with typical angina or positive electrocardiographic finding for myocardia ischemia.
2. Aged 20-80 years.

Exclusion criteria:

1. recipient of renal transplant graft or dialysis therapy