Historical Background
Angioplasty was first used by Dotter and Judkins in 1964 for the treatment of peripheral vascular lesions using rigid intravascular dilators. Although relatively unnoticed in the United States, this approach was used to treat large numbers of patients in Europe. Grüntzig substituted a balloon-tipped catheter for the rigid dilator and performed the first peripheral balloon angioplasty in 1974. Dotter also described the use of a tubular coiled wire stent graft in canines in 1969. Tillet and Garner isolated streptokinase in 1933, but it was not until the 1950s that Clifton and Grunnet first reported its use as a thrombolytic agent. In 1960 Luessenhop and Spence first described intravascular embolization to treat a cerebral arteriovenous malformation using a handmade plastic pellet.
Indications
Indications for percutaneous transluminal angioplasty (PTA) of specific anatomic sites are detailed in later chapters but typically include an occlusive lesion that is symptomatic or at high risk for causing significant morbidity should progression to complete occlusion occur. Specific indications for stenting after an initial angioplasty include flow-limiting dissection, residual stenosis of more than 30%, or the presence of a significant pressure gradient across the treated lesion. Primary stent placement is commonly practiced for carotid and renal interventions or for a lesion that is embolizing but has not proved beneficial over selective stenting in the iliac system. It is common to selectively stent infrainguinal lesions based on the postangioplasty results, and long-term outcomes for superficial femoral artery (SFA) stents, stent grafts, and drug-eluting stents are evolving.
The exact roles for adjunctive percutaneous mechanical thrombectomy and pharmacologic thrombolytic therapy are debated, but these modalities are predominantly considered in the setting of acute arterial or venous thrombosis. Atherectomy for chronic peripheral lesions is advocated by some, but its role is controversial with a paucity of randomized data.
Indications for intravascular embolization include control of hemorrhage, treatment of vascular anomalies, exclusion of aneurysmal segments or vessels that have been treated with an endograft, and interruption of tumor vasculature.
Preoperative Preparation
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History and physical examination, as well as noninvasive physiologic and imaging studies, establishes the location and severity of vascular disease.
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If angioplasty or stenting is planned, preprocedural administration of antiplatelet therapy with aspirin (325 mg daily) or clopidogrel (75 mg daily) is recommended for 5 days before the procedure. If patients have not received clopidogrel, an oral loading dose of 300 mg can be administered after the procedure.
Pitfalls and Danger Points
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Inadvertent embolization. Crossing any lesion can lead to inadvertent embolization, but irregular, ulcerated, or complex lesions, especially those that are symptomatic or aneurysmal with the presence of irregular thrombus, are at increased embolic risk. Judicious use of anticoagulation and cautious passage of atraumatic wires and intravascular devices through these lesions help minimize embolization.
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Dissection. Dissection may occur as a consequence of wire or catheter manipulation or after primary angioplasty. Dissection from a guidewire may be avoided by frequent “twirling” of the wire tip to ensure an intraluminal position. If the position of the catheter is in doubt, contrast angiography should be performed to identify a subintimal plane of dissection. Dissection after angioplasty occurs most frequently in the region of significant plaque burden or after overdilation of a vessel. Most iatrogenic dissections are clinically silent and are not flow limiting, but if a flow-limiting dissection is present, stenting is required.
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Rupture. Vessel rupture can occur with wire manipulation, balloon angioplasty, or insertion of other devices, such as a large sheath. Rupture after angioplasty is often secondary to overdilation of the lesion. Circumferentially and highly eccentric calcified lesions are at high risk of rupture and should be approached cautiously. Subintimal angioplasty may also increase the risk for perforation compared with intraluminal procedures.
Operative Strategy
All interventional procedures follow a common series of steps, beginning with vascular access and placement of an appropriate sheath. Puncture site planning and sheath sizing depend on the location of the lesion. For example, if both inflow and outflow lesions are suspected in the presence of unilateral lower extremity ischemia and diminished ipsilateral pulses, access through a retrograde puncture in the contralateral common femoral artery allows treatment of an inflow lesion using a 6-Fr sheath and 0.035-inch system, followed by treatment of the distal outflow lesion through a long 4-Fr sheath and 0.014-inch system placed within the 6-Fr sheath. An alternative strategy is treatment of the inflow lesion alone through a retrograde puncture on the affected side, followed by treatment of the outflow lesion via a separate antegrade puncture.
Operative Technique
Anesthesia
Most percutaneous procedures can be performed with local anesthesia and conscious sedation using a combination of narcotics and sedatives with continuous cardiovascular and respiratory monitoring. Occasionally patients are unable to tolerate a procedure because of anxiety, discomfort, or inability to lay immobile for prolonged periods in the interventional suite. In these instances a general anesthetic may be required.
Angioplasty
A stenosis may appear moderate on two-dimensional imaging yet cause no significant flow limitation. Multiple views or transduction of pressure gradients may be required when there is doubt as to a lesion’s hemodynamic significance. For example, multiple oblique images of the pelvic vasculature may be required to identify posterior lesions and better visualize hypogastric and profunda vessel origins in a nonoverlapping projection. When a decision has been made to intervene, a therapeutic dose of heparin (50-100 units/kg) is administered. The activated clotting time is often measured during the procedure to ensure therapeutic anticoagulation, frequently with a goal of greater than 200 seconds and greater than 250 seconds for carotid and tibial procedures, respectively.
Intervention in the form of balloon angioplasty is accomplished by exerting a radial force, with plaque fracture and intimal injury creating a larger flow channel. Dissection is frequently visible after angioplasty, but the flow-limiting characteristics of the dissection determine whether stent placement is required.
Balloon selection can be challenging because there is a great deal of variation in available devices and selecting an appropriate size requires some experience. Balloon catheters are either coaxial, in which there exist two separate hub lumens for guidewire and balloon inflation, or monorail, in which a single hub lumen exists for balloon inflation ( Fig. 5-1 ). Coaxial and monorail balloon catheters are typically used with 0.035- and 0.014-inch guidewires, respectively. Coaxial, or over-the-wire, balloons can be used on 0.014-inch systems for greater support. Balloons can vary in length from 2 cm to greater than 12 cm and in diameter from 1 to 40 mm ( Table 5-1 ). Most balloons are fabricated from polyethylene or nylon, which has a combination of strength and low compliance so that the balloon profile does not change shape as the inflation pressure is increased. All balloons are rated for the nominal pressure at which they obtain their reported diameter, in addition to their burst pressure at which 5% of balloons rupture. Balloons can rupture on sharp, calcified plaques or because of overinflation. When balloon rupture occurs, it is sometimes possible to compensate for the extravasation of contrast by exerting high volumes via an inflation device. If this fails to adequately dilate the lesion, a high-pressure balloon can be used that is less prone to rupture. An additional variable in balloon selection is the profile, which determines a balloon’s ability to cross a lesion. Low-profile balloons are more likely to cross tight lesions than high-profile balloons.
| PTA Balloons (0.035 inch) | |||
|---|---|---|---|
| Manufacturer Product | Shaft Length (cm) | Balloon Diameters (mm) | Balloon Lengths (mm) |
| Abbott Vascular Fox Cross | 50, 80, 135 | 3, 4, 5, 6, 7, 8, 9, 10, 12, 14 | 20, 30, 40, 60, 80, 100, 120 |
| AngioDynamics WorkHorse II | 50, 75, 100 | 5, 6, 7, 8, 9, 10 | 20, 40, 60 |
| Bard Peripheral Conquest | 50, 75, 120 | 5, 6, 7, 8, 9, 10, 12 | 20, 30, 40, 60, 80 |
| Bard Peripheral Atlas | 75, 120 | 12, 14, 16, 18, 20, 22, 24, 26 | 20, 40, 60 |
| Bard Peripheral Dorado | 40, 80, 120, 135 | 3, 4, 5, 6, 7, 8, 9, 10 | 20, 40, 60, 80, 100, 120, 150, 170, 200 |
| Boston Scientific Blue Max | 40, 75, 120 | 4, 5, 6, 7, 8, 9, 10 | 20, 30, 40, 80, 100 |
| Boston Scientific Synergy | 50, 75, 90, 135, 150 | 3, 4, 5, 6, 7, 8, 9, 10, 12 | 15, 20, 30, 40, 60, 80, 100 |
| Cook Medical ATB Advance | 40, 80, 120 | 4, 5, 6, 7, 8, 9, 10, 12, 14 | 20, 30, 40, 50, 60, 70, 80 |
| Cordis Opta Pro PTA | 80, 110, 135 | 3, 4, 5, 6, 7, 8, 9, 10, 12 | 10, 15, 20, 30, 40, 60, 80, 100 |
| Cordis Powerflex P3 PTA | 40, 65, 80, 110, 135 | 4, 5, 6, 7, 8, 9, 10 | 10, 15, 20, 30, 40, 60, 80, 100 |
| Cordis Maxi LD PTA | 80, 110 | 14, 15 | 20, 40, 60, 80 |
| ev3 EverCross 0.035 | 40, 80, 135 | 3, 4, 5, 6, 7, 8, 9, 10, 12 | 15, 20, 30, 40, 60, 80, 100, 120, 150, 200 |
| Medtronic Admiral Xtreme | 80, 130 | 3, 4, 5, 6, 7, 8, 9, 10, 12 | 20, 40, 60, 80, 120, 150, 200, 250, 300 |
| PTA Balloons (0.014 and 0.018 inch) | |||
|---|---|---|---|
| Manufacturer Product | Shaft Length (cm) | Balloon Diameters (mm) | Balloon Lengths (mm) |
| Abbott Vascular RX Viatrac 14 | 80, 135 | 4, 4.5, 5, 5.5, 6, 6.5, 7 | 15, 20, 30, 40 |
| Abbott Vascular Fox sv 18 | 90, 150 | 2, 2.5, 3, 4, 5, 6 | 15, 20, 30, 40, 60, 80, 100, 120 |
| Bard Peripheral Ultraverse 014 | 150 | 1.5, 2, 2.5, 3, 3.5, 4, 5 | 20, 40, 80, 120, 150, 220 |
| Bard Peripheral VascuTrak | 140 | 2, 2.5, 3, 3.5, 4, 5, 6, 7 | 20, 40, 60, 80, 100, 120, 150, 200, 250, 300 |
| Boston Scientific Sterling Monorail | 80, 135 | 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 8 | 10, 15, 20, 30, 40, 60 |
| Boston Scientific Sterling OTW | 40, 80, 135 | 4, 5, 6, 7, 8, 9, 10 | 20, 30, 40, 60, 80, 100 |
| Cook Medical Advance 14LP | 170 | 2, 2.5, 3, 4 | 20, 40, 60, 80, 120, 160, 200 |
| Cordis Sleek OTW PTA | 150 | 1.25, 1.5, 2, 2.5, 3, 3.5, 4, 5 | 15, 20, 40, 80, 100, 120, 150, 220 |
| Cordis Aviator Plus PTA | 142 | 4, 4.5, 5, 5.5, 6, 7 | 15, 20, 30, 40 |
| ev3 NanoCross 0.014 | 90, 150 | 1.5, 2, 2.5, 3, 3.5, 4 | 20, 40, 80, 120, 150, 210 |
| Medtronic Amphirion Deep OTW | 120, 150 | 1.5, 2, 2.5, 3, 3.5, 4 | 20, 40, 80, 120, 150, 210 |
| Medtronic Sprinter OTW | Variable | 1.5, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, 4 | 6, 10, 12, 15, 20, 25, 30 |
| Specialized Balloons | |||
|---|---|---|---|
| Manufacturer Product | Shaft Length (cm) | Balloon Diameters (mm) | Balloon Lengths (mm) |
| AngioScore AngioSculpt Scoring | 137 | 2, 2.5, 3, 3.5 | 10, 20 |
| Boston Scientific Peripheral Cutting (OTW and RX) | 50, 90, 140 | 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8 | 15, 20 |
| Stents (balloon expandable) | |||
|---|---|---|---|
| Manufacturer Product | Shaft Length (cm) | Stent Diameters (mm) | Stent Lengths (mm) |
| Abbott Vascular Omnilink Elite peripheral stent system | 80, 15 | 4-10 | 12, 16, 19, 29, 39, 59 |
| Boston Scientific Express LD | 75, 135 | 6-10 | 17, 25, 27, 37, 57 |
| Cook Medical Formula 418 (0.018) | 80, 135 | 5-8 | 12, 16, 20, 24, 30 |
| Cordis Palmaz iliac and renal stents (unmounted) | N/A | 4-8 | 10, 15, 20, 29 |
| Cordis Palmaz iliac stent (unmounted) | N/A | 8-12 | 30 |
| ev3 Visi-Pro (0.014, 0.018) | 80, 135 | 5-8 | 12, 17, 27, 37, 57 |
| ev3 IntraStent LD (unmounted) | N/A | 9-12 | 16, 26, 36, 56, 76 |
| Medtronic Bridge Assurant | 80, 130 | 6-10 | 20, 30, 40, 60 |
| Medtronic Racer | 80, 130 | 4-7 | 12, 18 |
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