What Are the Step-by-Step Procedures for Performing an Angiogram?

Vascular angiography is a minimally invasive imaging procedure used to visualize blood vessels and assess for abnormalities such as stenosis, occlusion, aneurysms, or arteriovenous malformations. The technique relies on the injection of iodinated contrast medium into the vascular system, followed by real-time X-ray imaging—typically using fluoroscopy—to capture dynamic blood flow.

The procedure begins with patient preparation: vital signs are monitored, baseline renal function is confirmed (especially serum creatinine and estimated glomerular filtration rate), and informed consent is obtained. Local anesthesia is administered at the puncture site—most commonly the femoral artery in the groin, though radial or brachial access may be used depending on clinical indication and operator preference.

Under fluoroscopic guidance, a small incision is made, and a needle is advanced into the target artery. A guidewire is then inserted, followed by a sheath to maintain vascular access. A diagnostic catheter is threaded over the wire into the region of interest—for example, the carotid arteries for cerebral evaluation or the coronary arteries for cardiac assessment. Once positioned, the catheter is flushed with heparinized saline to prevent clot formation, and contrast medium is injected in controlled boluses while continuous fluoroscopic images are acquired.

Modern angiographic systems often integrate digital subtraction angiography (DSA), which digitally removes bony and soft-tissue structures from the image, enhancing vessel contrast and clarity. Additional sequences—including arterial, capillary, and venous phases—may be captured to evaluate perfusion dynamics. Upon completion, the catheter and sheath are removed, and hemostasis is achieved via manual compression or a vascular closure device.

Post-procedure, patients are observed for complications such as access-site hematoma, contrast-induced nephropathy, allergic reaction to iodinated contrast, or distal embolization. Hydration and renal monitoring are emphasized in at-risk individuals, particularly those with preexisting chronic kidney disease.