Angioplasty


Angioplasty, also known as balloon angioplasty and percutaneous transluminal angioplasty, is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis.
A deflated balloon attached to a catheter is passed over a guide-wire into the narrowed vessel and then inflated to a fixed size. The balloon forces expansion of the blood vessel and the surrounding muscular wall, allowing an improved blood flow. A stent may be inserted at the time of ballooning to ensure the vessel remains open, and the balloon is then deflated and withdrawn. Angioplasty has come to include all manner of vascular interventions that are typically performed percutaneously.

Uses and indications

Coronary angioplasty

A coronary angioplasty is a therapeutic procedure to treat the stenotic coronary arteries of the heart found in coronary heart disease. These stenotic segments of the coronary arteries arise due to the buildup of cholesterol-laden plaques that form in a condition known as atherosclerosis. A percutaneous coronary intervention, or coronary angioplasty with stenting, is a non-surgical procedure used to improve the blood flow to the heart.
Coronary angioplasty is indicated for coronary artery diseases such as unstable angina, NSTEMI, STEMI and spontaneous coronary artery perforation. Percutaneous coronary intervention for stable coronary disease has been shown to significantly relieve symptoms such as angina, or chest pain, thereby improving functional limitations and quality of life.

Peripheral angioplasty

Peripheral angioplasty refers to the use of a balloon to open a blood vessel outside the coronary arteries. It is most commonly done to treat atherosclerotic narrowings of the abdomen, leg and renal arteries caused by peripheral artery disease. Often, peripheral angioplasty is used in conjunction with guide wire, peripheral stenting and an atherectomy.

Chronic limb-threatening ischemia

Angioplasty can be used to treat advanced peripheral artery disease to relieve the claudication, or leg pain, that is classically associated with the condition.
The bypass versus angioplasty in a study of severe ischemia of the leg investigated infrainguinal bypass surgery first compared to angioplasty first in select patients with severe lower limb ischemia who were candidates for either procedure. In this study, angioplasty was associated with less short term morbidity compared with bypass surgery; however, long term outcomes favor bypass surgery.
Based on this study, the ACCF/AHA guidelines recommend balloon angioplasty only for patients with a life expectancy of 2 years or less or those who do not have an autogenous vein available. For patients with a life expectancy greater than 2 of years life, or who have an autogenous vein, a bypass surgery could be performed first.

Renal artery angioplasty

is associated with hypertension and loss of renal function. Atherosclerotic obstruction of the renal artery can be treated with angioplasty with or without stenting of the renal artery. There is a weak recommendation for renal artery angioplasty in patients with renal artery stenosis and flash edema or congestive heart failure.

Carotid angioplasty

can be treated with angioplasty and carotid stenting for patients at high risk for undergoing carotid endarterectomy. Although carotid endarterectomy is typically preferred over carotid artery stenting, stenting is indicated in select patients with radiation-induced stenosis or a carotid lesion not suitable for surgery.

Venous angioplasty

Angioplasty is used to treat venous stenosis affecting dialysis access, with drug-coated balloon angioplasty proving to have better 6 month and 12 month patency than conventional balloon angioplasty. Angioplasty is occasionally used to treat residual subclavian vein stenosis following decompression surgery for thoracic outlet syndrome. There is a weak recommendation for deep venous stenting to treat obstructive chronic venous disease.

Contraindications

Angioplasty requires an access vessel, typically the femoral or radial artery or femoral vein, to permit access to the vascular system for the wires and catheters used. If no access vessel of sufficient size and quality is available, angioplasty is contraindicated. A small vessel diameter, the presence of posterior calcification, occlusion, hematoma, or an earlier placement of a bypass origin, may make access to the vascular system too difficult.
Percutaneous transluminal coronary angioplasty is contraindicated in patients with left main coronary artery disease, due to the risk of spasm of the left main coronary artery during the procedure. It is also not recommended if there is less than 70% stenosis of the coronary arteries, as stenosis is not hemodynamically significant below this level.

Technique

Access to the vascular system is typically gained percutaneously. An introducer sheath is inserted into the blood vessel via the Seldinger technique. Fluoroscopic guidance uses magnetic resonance or X-ray fluoroscopy and radiopaque contrast dye to guide angled wires and catheters to the region of the body to be treated in real time. Tapered guidewire is chosen for small occlusion, followed by intermediate type guidewires for tortuous arteries and difficulty passing through extremely narrow channels, and stiff wires for hard, dense, and blunt occlusions.
To treat a narrowing in a blood vessel, a wire is passed through the stenosis in the vessel and a balloon on a catheter is passed over the wire and into the desired position. The positioning is verified by fluoroscopy and the balloon is inflated using water mixed with contrast dye to 75 to 500 times normal blood pressure, with most coronary angioplasties requiring less than 10 atmospheres. A stent may or may not also be placed.
At the conclusion of the procedure, the balloons, wires and catheters are removed and the vessel puncture site is treated either with direct pressure or a vascular closure device.
Transradial artery access and transfemoral artery access are two techniques for percutaneous coronary intervention. Transradial artery access is the technique of choice for management of acute coronary syndrome as it has significantly lower incidence of bleeding and vascular complications compared with the transfemoral artery approach. It also has a mortality benefit for high risk patients with acute coronary syndrome and who are at high risk of bleeding. Transradial artery access was also found to yield improved quality of life, as well as decreased healthcare costs and resources.

Risks and complications

Relative to surgery, angioplasty is a lower-risk option for the treatment of the conditions for which it is used, but there are unique and potentially dangerous risks and complications associated with angioplasty:
Angioplasty may also provide a less durable treatment for atherosclerosis and be more prone to restenosis relative to vascular bypass or coronary artery bypass grafting. Drug-eluting balloon angioplasty has significantly less restenosis, late lumen loss and target lesion revascularization at both short term and midterm follow-up compared to uncoated balloon angioplasty for femoropopliteal arterial occlusive disease. Although angioplasty of the femoropopliteal artery with paclitaxel coated stents and balloons significantly reduces rates of vessel restenosis and target lesion revascularization, it was also found to have increased risk of death.

Adjunctive therapy

Rotational Atherectomy, or "rotablation", is a technique used to treat heavily calcified coronary artery lesions by ablating plaque with a diamond-encrusted burr rotating at high speeds. It improve vessel lumens for balloon dilation and stent implantation. While effective for complex cases like calcification of nodules and tortuous vessels, its use is limited by procedural complexity, lack of training, and a need for specialized equipment. High procedural success rates are reported, especially with skilled operators, but careful patient selection is crucial to minimize complications. Studies show RA's efficacy in comparison to alternative techniques, particularly for challenging lesions.
Atherectomy is an adjunctive therapy used for lesion preparation of calcified plaque before percutaneous coronary intervention. The goal of lesion preparation with atherectomy is to modify calcified plaque, which changes the lesion compliance and allows for adequate balloon and stent expansion in segments with heavily calcified lesions.

Atherectomy techniques

Rotational Atherectomy

Rotational atherectomy modifies plaque through rotational ablation using a diamond-tipped burr that spins concentrically on the wire. This technique is particularly useful for heavily calcified lesions that are resistant to balloon angioplasty.

Orbital Atherectomy

Orbital atherectomy employs an eccentrically mounted diamond-coated crown that orbits within the vessel, sanding down calcified deposits. This method has a reduced risk of burr entrapment compared to rotational atherectomy.

Excimer Laser Coronary Angioplasty

Excimer laser coronary angioplasty uses pulsatile ultraviolet laser energy to precisely ablate plaque tissue. It is effective in modifying undilatable and uncrossable lesions, facilitating subsequent balloon angioplasty and stent deployment.
Atherectomy is a valuable adjunctive therapy for patients with coronary artery disease, particularly those with severely calcified lesions where traditional balloon angioplasty and stenting may be insufficient. Its success depends on the selection of appropriate devices and the operator's expertise in managing the technical nuances to minimize complications. Studies have demonstrated that atherectomy can enhance procedural success rates and long-term outcomes in complex cases. However, further research and standardized protocols are needed to address challenges and expand its clinical applications effectively.