4 Complications of Percutaneous Coronary Interventions

Percutaneous coronary intervention (PCI) is associated with rare but serious complications. Most of the complications are generic to all diagnostic coronary angiography procedures and some are specific to coronary intervention. Events like death, myocardial infarction (MI), and bleeding occur at higher rates for interventional procedures since there is prolonged procedural time, complexity, and the use of anticoagulation (see Tables 4-1 and 4-2). It is critical to understand the possible complications of PCI in order to provide proper informed consent to the patient. It is also critical to be vigilant and to recognize potential complications at an early stage to try to reverse the adverse outcome, as the most common cause of all post-PCI deaths is from a procedural complication rather than from a preexisting cardiac condition. Fortunately, death is very rare with diagnostic angiography (<0.1%). The mortality rate increases 13 times with the addition of the complexity of coronary intervention to 1.3% (see Table 4-3).

^{Table 4-1} Event Rates of Diagnostic Versus PCI Complications

Complication	Event Rate Diagnostic Procedure (%)	Event Rate Interventional Procedure (%)
Death	0.1	1.3
Significant bleed	0.5	5–12
AV fistula	0.75	1.1
Pseudoaneurysm	0.2	1–2
Contrast-induced nephropathy	5	8–57
Periprocedural MI (>3xULN cardiac enzyme)	0.1	8
Air embolism	0.1–0.3	0.1–0.3
Cerebrovascular accident	0.3	0.3
Ventricular arrhythmia	0.4	0.84
Coronary dissection	.03–0.46	29–50
Aortic dissection	<.01	.03
Infection/bacteremia	.11	0.64
Anaphylactoid reaction to contrast	0.23	0.23
Cholesterol embolization	0.8–1.4	0.8–1.4

AV, arteriovenous; MI, myocardial infarction; ULN, upper limits of normal.

^{Table 4-2} Complications Specific to PCI

Complication	Event Rate (%)
No-reflow phenomenon	2
Stent thrombosis	2
Vessel perforation	0.84
Stent embolization	0.4–2
Need for emergent bypass surgery	0.15–0.3
Wire fracture	0.1
Stent infection	<.1 (case reports only)

^{Table 4-3} Modes of Death During PCI

Mode of Death	Event Rate (%)
Low output failure	66.1
Ventricular arrhythmias	10.7
Stroke	4.1
Preexisting renal failure	4.1
Bleeding	2.5
Ventricular rupture	2.5
Respiratory failure	2.5
Pulmonary embolism	1.7
Infection	1.7

Adapted from Table 1, page 633 of Malenka DJ, O’Rourke D, Miller MA et al. Cause of in-hospital death in 12,232 consecutive patients undergoing percutaneous transluminal coronary angioplasty. Am Heart J 1999; 137(4):632-638.

Complications of PCI can occur at any step of the procedure, from the administration of sedation to the transfer as the patient leaves the laboratory. This chapter will discuss many of the possible complications in the order that they might be encountered during the procedure.

Vascular Access

The first part of any PCI begins with vascular access. Using the femoral access, the major complications are femoral artery dissections (Fig. 4-1A, B), pseudoaneurysm, arteriovenous (AV) fistula, and retroperitoneal bleeding. As seen in Table 4-1, the incidence of these complications is increased compared to a strictly diagnostic procedure. All arterial complications are markedly reduced using the radial artery access.

Figure 4-1 A, Cineangiogram frame of femoral artery dissection. This problem may be associated with limb ischemia or bleeding. It may require surgery but more often can be treated by contralateral access and implantation of iliac stent. B, Ultrasound picture of a pseudoaneurysm (P) arising from the common femoral artery (CFA). The circular color object is the hematoma which is fed by blood flow from the artery through the characteristic narrow neck (N).

(From Ahmad F, Turner SA, Torrie P, et al. Iatrogenic femoral artery pseudoaneurysms—a review of current methods of diagnosis and treatment. Clin Radiol 2008; 63:1310-1316, Fig. 1.)

A femoral artery pseudoaneurysm represents failure of sealing of the initial arterial puncture site, allowing arterial blood to flow into the surrounding tissue. This forms a pulsatile hematoma that acts as the covering roof of the aneurysm (see Fig. 4-1A, B). Pseudoaneurysms are late appearing, associated with local pain and swelling and diagnosed with femoral ultrasound with an excellent sensitivity of 94% to 97%. There are multiple risk factors for pseudoaneurysm (see Table 4-4).

^{Table 4-4} Risk Factors for Pseudoaneurysm Formation

Procedural Factors

Catheterization of both artery and vein

Cannulation of the superficial femoral or profunda femoris rather than common femoral

Inadequate compression post procedure

More anticoagulation used

Patient Factors

Obesity

Hemodialysis

Calcified arteries

Small pseudoaneurysms (<2 cm) often close spontaneously within 1 month. In larger pseudoaneurysms, or in small ones that fail to close, active treatment is necessary. The two most common treatment methods are ultrasound guided compression or thrombin injection. In some hospitals, ultrasound guided compression is not offered because of increased stress-related wrist injury to the ultrasound technician. Other advantages of thrombin injection over ultrasound compression are seen in Table 4-5.

^{Table 4-5} Advantages of Thrombin Injection Compared With Ultrasound Compression

Greater technical success (96% vs. 74%)

Less painful to the patient and technician

No conscious sedation required

Effective in patients on anticoagulation

Can be used in pseudoaneurysms above the inguinal ligament

Thrombin injection can be performed by diluting 1000 U into a 1 mL syringe with normal saline (final concentration of 100 U per 0.1 mL) and injected with direct ultrasound visualization through a long 22-gauge needle until thrombus is formed in the pseudoaneurysm cavity and Doppler-detected flow is abolished (see Fig. 4-2A, B). Rarely, in very large pseudoaneurysms and those resistant to thrombin injection, vascular surgery is required.

Figure 4-2 A, Schematic representation of the technique utilized to inject thrombin into a pseudoaneurysm under ultrasound guidance. (From Ahmad F, Turner SA, Torrie P, et al. Iatrogenic femoral artery pseudoaneurysms—a review of current methods of diagnosis and treatment. Clin Radiol 2008; 63:1310, Fig. 3.) B, Cineangiogram of arteriovenous fistula. Contrast visualized in the vein returning cranially indicates a communication with the artery, i.e., a fistula. Treatment is described in the text.

Another complication of vascular access is AV fistula formation (Fig. 4-2A, B). This is recognized on physical exam by a palpable thrill or an audible continuous bruit. Unlike pseudoaneurysms, conservative treatment with watchful waiting is the most common treatment modality (90%). One third of persistent AV fistulae will close during the first 12 months. Most persistent AV fistulae are asymptomatic and do not require repair. Rarely, they can be symptomatic (moderate pain) and, in large patient series, about 10% of AV fistulae will ultimately require surgical repair.

AV fistulae produce low shunt blood flow volumes (160–510 mL/min) compared to most large intracardiac (e.g., left to right) shunts or dialysis shunts (1000 mL/min). AV shunt flows must exceed 30% of the cardiac output to produce symptoms, and therefore it is quite rare to have a truly symptomatic shunt from a femoral AV fistula. The main risk factor for development of an AV fistula is a low arterial puncture, responsible for almost 85% of all AV fistulae.

Infection

A rare complication of groin access is systemic infection. The Society for Coronary Angiography and Intervention has detailed infection control guidelines for the cardiac catheterization laboratory. Proper sterile technique, including hand washing, use of hats, masks, gown, and gloves, has limited bacterial infections to occur in only 0.64% of interventional cases with septic complications in only 0.24% of cases. Routine antibiotic prophylaxis is not recommended before cardiac catheterization. However, if there is any concern for contamination of the femoral sheath (transport between rooms, patient touching site, changing out sheaths in a delayed procedure), it is standard to give 1 gram of cephalexin as a prophylactic measure. If the patient is allergic, 1gram of vancomycin can be given alternatively.

An equally concerning infectious complication is the exposure of the physicians or staff to the patient’s potential pathogens. Universal precautions are to be followed by everyone in the catheterization laboratory. If there is an occupational exposure, proper management per your hospital guidelines should be followed. See Table 4-6 for U.S. Public Health Service guidelines.

^{Table 4-6} Management of Occupational Exposure to Hepatitis B Virus, Hepatitis C Virus, and HIV

I. Definition: Direct contact with blood or body fluids (including percutaneous injury), contact of mucous membranes, or skin contact, especially if abraded.

II. Procedure

A. Clean site of exposure with soap and copious amounts of water; flush mucous membrane with large quantities of water.

B. Victim should report incident promptly, including patient/source information.

C. Provide wound care and review with victim tetanus and hepatitis B prophylaxis information.

D. Counsel and obtain consent for HIV testing from both victim and patient/source.

E. Order the following laboratory specimen with appropriate consent obtained:

1. Victim: hepatitis C antibody, hepatitis B surface antigen, HIV

2. Patient: hepatitis B surface antigen and core antibody, hepatitis C antibody, ALT, RPR, HIV

F. Review hepatitis B vaccination and response status of victim and follow postexposure prophylaxis to hepatitis B protocol

G. If patient is hepatitis C positive or has elevated ALT:

1. Follow postexposure prophylaxis to hepatitis B protocol.

2. Follow up for anti-HIV therapy per protocol.

3. Schedule hepatitis C and HIV testing for 6 weeks, 3 months, and 6 months.

ALT, alanine aminotransferase; HIV, Human Immunodeficiency Virus; RPR, rapid plasma reagin.

Adapted from Table 2, page 85 of Chambers C, Eisenhauer M, McNicol L, et al. Infection control guidelines for the cardiac catheterization laboratory: society guidelines revisited. Catheter Cardiovasc Interv 2006;67:78–86.

Bleeding

The last and most dangerous complication of groin access is major femoral bleeding. Large femoral hematomas have an incidence of 2.8% compared to a 0.3% incidence of retroperitoneal bleeds. A retroperitoneal hematoma or a significant femoral hematoma (>5 cm) often requires blood transfusions and prolonged hospitalization. More significant bleeds can require surgery, and significant bleeding in relation to PCI has been shown to correlate with mortality. Significant risk factors for major femoral bleeding are listed in Table 4-7.

^{Table 4-7} Significant Risk Factors for Major Femoral Bleeding

Risk Factor	Odds Ratio
Age >75 vs. <55	2.59
Heparin use postprocedure	2.46
Severe renal impairment	2.25
Age 65–74 vs. <55	2.18
Female patient	1.64
Closure device use	1.58
Sheath size 7F–8 F vs. <6	1.53
GP IIb/IIIa use	1.39
Longer procedure duration	1.2

Adapted from Doyle B, Ting HH, Bell MR, et al. Major femoral bleeding complications after PCI. JACC Cardiovasc Interv 2008;1(2):202–209.

The bleeding complication of most concern is a retroperitoneal hematoma, as large amounts of blood can fill the pelvic cavity and shock can develop rapidly. If a retroperitoneal bleed is suspected (see Table 4-8), volume (crystalloid solutions) should be given and blood should be ordered immediately for transfusion as soon as available. A vascular surgeon should also be consulted immediately. If the patient remains hemodynamically unstable despite volume resuscitation, surgery or endovascular repair (covered stent placement) may be needed; this occurs in approximately 16% of patients. However, the majority (84%) of cases can undergo a conservative “watchful waiting” strategy, as the hematoma usually stabilizes from tamponade of the initial site of extravasation. A computed tomography (CT) scan will be confirmative of the clinical diagnosis and should only be ordered once the patient is stable. Vascular surgeons use the CT scan as a baseline study and as a method to localize the origin of the bleed (if radiographic contrast media is used). Most retroperitoneal hematomas are caused by bleeding from the external iliac artery above the inguinal ligament or inferior epigastric artery. Rarely, bleeding below the inguinal ligament can track between tissue planes and extend into a retroperitoneal accumulation. Bleeding might also rarely extend to the scrotum through extension along the spermatic cord. Most cases of scrotal hematoma can also be managed conservatively with elevation and ice. However, rarely, large tense scrotal hematomas can cause significant pain and may compromise the viability of the scrotal skin and/or testicle which would require urgent surgical exploration (Fig. 4-3).

^{Table 4-8} Classical Signs and Symptoms of Retroperitoneal Bleed

Transient response to fluid loading

Grey Turner sign (bruising along flank) [late appearing]

Cullen sign (bruising around umbilicus) [late appearing]