Introduction to Coronary Angioplasty

Click the underlined equipment headings to read about each item in more depth (if the link doesn’t work, I haven’t finished the page yet, but I assure you it’ll be up soon). 

Coronary angiograms are minimally-invasive procedures designed to visualise the arteries of the heart. By injecting contrast dye directly into the arteries, X-rays allow practitioners to see any narrowings within the vessels, and then proceed to reopen them using a variety of tools (angioplasty).Access

 

Coronary access is most commonly gained through either the femoral or radial artery. Despite possessing a steeper learning curve, radial access is now preferred due to it having a statistically lower risk of major bleeding (73% lower, in fact), but femoral access is still utilised for reasons such as operator preference, or radial complication.

Aside from the staff, monitoring and X-ray equipment, Catheterisation of the cardiac anatomy requires a set of stock kit (*normally* used in the order listed here):

Introducer Needle & Sheath: The needle, or trocar, is a hollow needle used for vascular access. Once inside the desired vessel, the sheath is passed through the needle lumen, and this is used to facilitate the insertion of a guidewire

Guidewire: Guided by fluoroscopy, a straight or J-tipped wire is advanced through the arterial system through to the ascending thoracic aorta, over which the catheter is applied.

Catheters: Long, plastic tubes through which contrast dye can be injected so as to allow visualisation of the arterial structure. There are a variety of different catheter shapes and sizes, each being suited to the vessel size, and the area of anatomy being viewed. In addition to diagnostic catheters, guide catheters are used to advance interventional kit through the vessels, and some specialist catheters are used for measurements in pressure studies.

Pressure Wires: Used to assess the degree of sclerosis within the vessel via pressure-sensitive wire tip. Not all lesions need to opened via ballooning/stenting; some smaller plaques can be managed pharmaceutically, so Instantaneous Free-wave Ratio (iFR) and Fractional Flow Reserve (FFR) measurements give values indicating how flow-limiting a lesion may be, and help determine what kind of treatment will be required, as well as the improvement in flow present after any intervention.

IVUS: Intra-vascular Ultrasound provides a visual representation of the interior vessel, including the degree of stenosis present. It allows for the determination of necessary balloon size, stent size, and treatment success if relevant.

Cutting Balloons: Small balloons with blades (atherotomes) attached to their surface. Upon inflation, these balloons score the plaque in a uniformed manner, creating weaknesses in the lesion akin to fault-lines. Useful in treating in-stent restenosis

Pre-dilatation Balloons: Before stenting, these balloons are inflated in order make the occluded artery more patent.

Stents: These mesh “scaffolds” are packaged over balloons, which are inflated in the occluded section of the artery and once deployed, they remain in place, holding it open. Most modern stents are either coated with, or elute, a pharmaceutical agent designed to minimize the risk of restenosis.

Post-dilatation Balloons: Typically used after the deployment of a stent, non-complaint balloons are more rigid than their pre-dilatation counterparts, and can be safely inflated to higher atmospheres. Studies have shown them to be effective at widening the stents once they are in situ.

Wound Closure: Vascular Closure Devices (VCDs) aim to facilitate haemostasis at the vascular insertion point. Historically, manual pressure was used, and in many ways, this remains the gold standard. VCDs, however, allow continued anticoagulation, and do not require clinical staff to be in attendance for prolonged periods of time.

Heart

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