Coronary Angiography: Preparation and Procedure
Coronary angiography is the gold standard invasive procedure for evaluating coronary artery disease, involving catheter insertion through arterial access to visualize coronary vessels using contrast media under X-ray guidance. 1
Preparation for Coronary Angiography
Prior to the procedure, patients should undergo a comprehensive risk assessment to identify factors that may increase complications, including cardiomyopathy, cerebrovascular disease, and renal dysfunction 2
For patients at risk of contrast-induced acute kidney injury (CI-AKI), intravenous volume expansion with either isotonic sodium chloride or sodium bicarbonate solution is recommended rather than oral fluids alone 2
The recommended hydration protocol is 3 ml/kg of isotonic fluid over 1 hour before the procedure, followed by 1 ml/kg/hour for 6 hours post-procedure to maintain adequate urinary flow rates 2
Nephrotoxic medications such as NSAIDs and metformin should be temporarily discontinued before the procedure 2
For diabetic patients, insulin and dextrose infusion may be required during the procedure, with oral hypoglycemics being withdrawn 2
Antiplatelet therapy with aspirin (75-150 mg daily) and/or clopidogrel may be administered before the procedure, particularly in patients with suspected acute coronary syndrome 2
Procedural Details
Coronary angiography is performed in a cardiac catheterization laboratory under sterile conditions with continuous ECG and hemodynamic monitoring 2
Arterial access is obtained through either:
- Femoral artery (traditional approach)
- Brachial artery using percutaneous or cutdown techniques 2
- Radial artery (increasingly common due to lower bleeding risk)
A catheter is inserted through the arterial access site and advanced to the heart under fluoroscopic guidance 2
The lowest possible dose of contrast medium should be used, particularly in patients at risk for CI-AKI 2
Either iso-osmolar or low-osmolar iodinated contrast media is recommended rather than high-osmolar agents to reduce the risk of CI-AKI 2
Multiple angiographic views are obtained by injecting contrast media through the catheter while recording X-ray images to visualize the coronary arteries from different angles 2
Left ventriculography and aortography may also be performed during the same procedure to evaluate cardiac function and aortic pathology 1
Analysis and Documentation
Coronary angiography assessment should include:
- Identification and quantification of coronary stenoses
- Analysis of lesion characteristics (calcification, thrombus, aneurysm)
- Assessment of collateral circulation
- Evaluation of coronary flow patterns 2
For patients with previous bypass surgery, analysis of vascular conduits (coronary bypass grafts, left internal thoracic grafts) should include assessment of origin patency, body, anastomotic sites, flow patterns, and abnormalities 2
Digital imaging systems are now standard for coronary angiography, allowing for improved image quality, storage, and analysis compared to traditional film-based systems 2
Risks and Complications
Major complications of coronary angiography include:
- Vascular access site complications (bleeding, hematoma)
- Contrast-induced nephropathy
- Stroke or cerebrovascular events
- Arrhythmias
- Coronary artery dissection 3
Predictors of major complications include cardiomyopathy, severe valvular disease, renal insufficiency, and advanced age 2
The overall risk of serious complications is relatively low (approximately 1-2%), with mortality rates of less than 0.1% 3
Emerging Alternatives
Coronary computed tomography angiography (CCTA) has emerged as a non-invasive alternative to conventional coronary angiography for certain clinical scenarios 4
CCTA is particularly powerful for ruling out coronary artery disease and may be appropriate for preoperative coronary assessment before valve surgery 5
However, conventional coronary angiography remains the gold standard for evaluating coronary artery disease, especially when revascularization is being considered 1, 6