CHAPTER 23 Vascular Complications after Percutaneous Coronary Intervention

Arterial Access and Sheath Removal Techniques

VASCULAR ACCESS complications are the most common complications (2% to 6%) after diagnostic cardiac catheterization and coronary interventions despite their significant decline over the last decades.^1,² Care providers in the coronary care unit (CCU) should be familiar with the incidence, clinical presentation, and appropriate management of these complications. Critically ill patients admitted to the CCU are at high risk for access complications because of the presence of comorbidities such as peripheral vascular disease, renal failure, and advanced age. These patients are also more likely to be heavily anticoagulated, and to have had high-risk, technically demanding procedures on an emergency basis.^2,³

In addition, patients are occasionally admitted to the CCU for management of vascular access complications. A thorough understanding of vascular access issues and prompt recognition of these complications are essential to minimize the substantial morbidity and mortality associated with them.

The complications can be categorized as hemorrhagic or thrombotic/occlusive. Hemorrhagic complications include access site bleeding, retroperitoneal hematoma, pseudoaneurysm, arteriovenous fistula, and vessel laceration. Thrombotic complications include arterial thrombosis, distal embolization, dissection, and rarely venous thrombosis or pulmonary embolism. Risk factors include advanced age, female gender, obesity, peripheral vascular disease, use of large arterial sheaths, intensity of anticoagulation including the use of glycoprotein (GP) IIb/IIIa inhibitors, recent thrombolysis, intra-aortic balloon pump counterpulsation, and prolonged duration of time that the sheath remained in place.⁴^–⁶ Meticulous technique during cardiac catheterization and during the removal of the sheath is essential in reducing the complications rate.

Arterial Access and Sheath Removal Techniques

A focused but detailed clinical examination of the access site before the patient is taken to the catheterization laboratory is essential. The femoral and distal pulses are palpated, and their presence or absence is documented; the groin is auscultated for bruits and inspected for the presence of infections and surgical scars that point to prior peripheral vascular bypass procedures. In radial artery cases, a modified Allen test is performed using the waveform of the pulse oximeter to detect distal perfusion.

The femoral approach is the site of choice for most operators. The common femoral artery is the point of entry. In most patients, the bifurcation of the common femoral artery is at the level of the mid third of the femoral head.⁷ Time should be taken to palpate the femoral pulse at the site of maximal impulse. This should be 2 cm below the inguinal ligament, which runs across a line connecting the anterior superior iliac spine and the symphysis pubis. We also strongly recommend the use of fluoroscopy to identify the mid third of the head of the femoral bone as an additional point to assist with orientation; this is particularly important in obese patients in whom the skin landmarks can be deceiving. The additional time required for this extra step is worthwhile, and fluoroscopy should be performed even under the most emergent circumstances. Arterial entry above the inguinal ligament predisposes to retroperitoneal hematomas, whereas low entry predisposes to formation of pseudoaneurysms and arteriovenous fistulas.⁸

Front wall technique should be used. The use of the smallest arterial sheaths that would allow for optimal performance of the percutaneous coronary intervention should be used because it has been shown that larger sheaths are associated with higher incidence of hemorrhagic and occlusive/thrombotic complications.⁹ Patients after fibrinolysis and patients who have been heavily anticoagulated should be catheterized by the most experienced operators. Patients anticoagulated with warfarin should ideally wait until the international normalized ratio (INR) is less than 1.5, although in emergency situations with good access technique and careful sheath removal or the use of closure devices by experienced operators, an INR of 2 to 3 is not an absolute contraindication to the procedure.¹⁰

Patients with severe peripheral vascular disease often are a challenge. Femoral artery atherosclerosis and calcification, iliac tortuosity, and stenosis make arterial access difficult and pose problems to wire advancement, sheath insertion, and catheter manipulation. In situations such as this, when there is any question regarding the intraluminal position of the 0.035-inch wire (resistance, buckling, trapping), we strongly recommend against use of force and further advancement of the wire and against the introduction of a large sheath. A 4F introducer can be slowly inserted, and after pressure transduction a gentle contrast injection is used to confirm the intraluminal position and to define the vascular anatomy. Stiff hydrophilic wires are useful to negotiate calcified tortuous iliac arteries, but their use should be restricted to experienced operators.

When the sheath is introduced, we use the over the wire exchange technique with the tip of the catheter in the proximal abdominal or distal thoracic aorta. In addition, we often use long, stiff sheaths to facilitate catheter manipulation because otherwise it might be impossible to have control of the coronary diagnostic or guiding catheters. We routinely perform catheter exchanges and observe the wire under fluoroscopy as we advance it in the iliac artery to get a sense of the tortuosity and elasticity of the artery, which determines the use of appropriate equipment to optimize the chances of a successful intervention.

Sheaths should be removed as soon as it is safe after a procedure depending on the anticoagulation regimen used for the intervention. The use of bivalirudin compared with the use of heparin plus GP IIb/IIIa inhibitors is associated with a reduction of vascular complications.³ For anticoagulation with heparin, an activated coagulation time of less than 180 seconds¹¹ is considered the criterion for safe sheath removal. If a GP IIb/IIIa inhibitor is used, some clinicians advocate an activated coagulation time of less than 150 seconds. With bivalirudin use, sheaths can be removed 2 hours after discontinuation of the bivalirudin.³

Throughout the time of sheath removal, the patient’s vital signs should be monitored closely, the access site should be assessed for the development of oozing or hematoma formation, and the distal pulses and color of the skin should be continuously assessed to ensure adequate perfusion of the limb. We strongly recommend the presence of at least two experienced nurses (or physicians) during sheath removal, frequent (every few minutes) measuring of the blood pressure, continuous telemetry and pulse oximetry monitoring, the availability of at least two reliable peripheral intravenous access sites, and atropine and normal saline available in the room.

Vagal episodes are common with compression of the femoral artery and are characterized by nausea, vomiting, hypotension, and bradycardia. These episodes usually respond promptly to intravenous fluids and atropine, 0.6 to 1 mg intravenously. If the pressure decreases again, and if there are other signs or symptoms such as flank or abdominal pain or palpable hematoma, the situation should be readdressed quickly because these are warning signs of potentially more serious complications, such as retroperitoneal hematoma or groin bleeding. It is a common mistake to misdiagnose significant bleeding episodes as “vagal episodes” with detrimental delays in appropriate management.

In patients with peripheral bypass grafts, we avoid total occlusion of the femoral artery, and we use continuous Doppler monitoring of the distal pulses to ensure uninterrupted blood flow through the graft. We generally recommend 15 minutes of manual compression for 6F sheaths, and we add 5 minutes for each French increase in size (i.e., 20 minutes for 7F and 25 minutes for 8F sheaths). Alternatively, mechanical compression devices can be used (C-clamp, fem-stop); although more convenient for the staff, these devices have a learning curve and still require the presence of staff members during the application. Closure devices are advocated because they are more comfortable for the patient allowing faster ambulation. In the past, there were concerns that bleeding or thrombotic/occlusive complications might be increased.¹²^–¹⁴ With the exception of Vasoseal,¹⁵ however, the complication rate with closure devices is similar to the rate with manual sheath removal except for a slight increase in infectious complications.