Vascular Access in Cardiac Catheterization and Intervention 

Updated: Dec 10, 2016
Author: Shabir Bhimji, MD, PhD; Chief Editor: Richard A Lange, MD, MBA 

Overview

Background

Cardiac catheterization is performed for both therapeutic and diagnostic reasons.[1, 2] Like any invasive procedure, cardiac catheterization is associated with complications, so the decision to undertake the procedure should be based on the risks and benefits.

More than a million cardiac catheterizations are performed each year in the United States. Several approaches to cardiac catheterization have been developed over the past 40 years. The three most widely used techniques for cardiac catheterization involve access through the femoral, radial, or brachial artery, with access to the brachial artery usually obtained by a cutdown approach and the others via a percutaneous approach.

Traditionally, the heart has been accessed via the femoral artery; however, in the last decade, the radial artery has been more widely used, since it (1) is readily accessible (even in obese individuals), (2) is the preferred site of access by many patients, (3) is associated with a lower incidence of hemorrhage, and (4) allows earlier ambulation of the patient following the procedure than a femoral catheterization. Since the radial artery is of a smaller caliber than the femoral artery, the radial artery cannot accommodate large-size catheters, spasms in some cases (thereby preventing catheter passage), and occludes in 5%-10% of patients postprocedure, although this seldom causes symptoms.

Indications

Indications for cardiac catheterization include the following:

  • To confirm the presence of suspected coronary artery disease (CAD) and define its anatomical location and severity

  • To perform angioplasty or stenting in a patient with symptoms of CAD

  • To determine the presence and severity of valvular heart disease

  • To assess the presence of CAD in patients who are referred for cardiac surgery so that concomitant bypass surgery can be performed, if indicated

  • To provide anatomic and hemodynamic information on the various heart chambers and great vessels

  • To assess the presence of pulmonary embolism and/or efficacy of treatment with thrombolytic therapy

  • To help confirm angiographic and hemodynamics before initiating therapy in patients with suspected hypertrophic cardiomyopathy

  • To provide details about potential responsiveness of the vessel to vasodilators in patients with pulmonary hypertension

  • To assess the presence of CAD in patients with chest pain of uncertain origin in whom there is confusion about the presence of CAD (ie, who are unable to undergo noninvasive testing or who have indeterminate nondiagnostic stress test results)

Contraindications

Over the years, the technique of cardiac catheterization has greatly improved and is usually tolerated by patients with acute myocardial infarction, ventricular tachycardia, or cardiogenic shock. Currently, the only absolute contraindication to cardiac catheterization is the inability of the patient to provide consent.

Relative contraindications include the following:

  • Severe uncontrolled hypertension and/or pulmonary edema; these should be controlled prior to the procedure

  • Decompensated left-sided heart failure

  • Severe ventricular irritability that may complicate interpretation of left-sided heart catheterization

  • Reversible anemia, which should be corrected with blood transfusions

  • Hypokalemia

  • Digitalis toxicity

  • Allergy to contrast dye

  • Acute or ongoing renal failure, without dialysis

  • Bleeding disorder, including warfarin therapy

Technical Considerations

Procedure Planning

It is important to select the right patient for radial artery intervention. Ideal features for good outcome include the following features:

  • Hemodynamically stable patient

  • Preferably younger than 70 years

  • No prior history of radial or brachial artery intervention

  • Palpable radial artery with a strong pulse

  • Normal Allen test result

Complication Prevention

Complications tend to be more common in patients with anatomical abnormalities. Complications associated with radial artery access do occur but are far more tolerated and milder than those associated with femoral access.[3, 4, 5]

Spasm is the most common complication of radial artery cannulation and may be reduced by administering ample patient sedation, using smaller-caliber sheaths, and using antispasmodic medications. Wiping the catheters with verapamil or papaverine may help prevent arterial spasm. If spasm of the vessel occurs, adequate time should be given for it to relax in order to avoid perforation of the vessel.[6]

Hematoma can occur with arterial access. Most cases can be prevented by firm digital pressure after sheath removal. In rare cases, with radial catheterization, the hematoma may occur in the axilla or neck area after wire perforation of the vessel.

Compartment syndrome can be limb-threatening but is very rare. This complication is best avoided by preventing it, which may include adequate control of pain, discontinuation of thrombolytics when not needed, use of external compression, and close monitoring of the extremity. Upon any evidence of compartment syndrome, a vascular consult should be obtained immediately.[2, 7]

Radial artery occlusion is not a concern if the ulnar artery is patent. However, if the palmar arch is not patent, heparin therapy may be administered to assist in reestablishing blood flow. Risk factors for radial/femoral artery occlusion include the following:

  • Small artery/large catheter mismatch

  • Female sex

  • Lack of heparin use

  • Diabetes

  • Prolonged artery compression due to bleeding

Artery dissection and perforation often occur when the wire is advanced despite resistance. To prevent this complication, the wire should be advanced under fluoroscopy and discontinued upon any resistance. Dissections and perforations are easily diagnosed during angiography. If small, most will close spontaneously. In rare cases, a covered stent may be placed across the perforation.

Pseudoaneurysms of the femoral and radial artery have been reported but are rare. Most can be controlled by applying local pressure. In some cases, these pseudoaneurysms may enlarge, and a vascular surgical consult may be required.

Late bleeding at the catheter site occurs in occasional cases. Hence, at discharge, all patients are instructed to observe their hand/groin for the following 24 hours. If bleeding occurs, the patient should apply digital pressure for at least 30-45 minutes. If this persists, the patient may need to return to the emergency room for better assessment of the site. In most cases, the bleeding is minor. In general, bleeding at the radial site is better tolerated than that seen in the groin.[2, 7]

Procedural failure results from an inability to gain artery access or to successfully visualize the coronary vessels. The latter may be due to anatomic variations or tortuosity in the radial, brachial, or subclavian vessels. Procedural failure generally lessens with experience but still occurs in about 5% of cases.

Certain types of hydrophilic-coated sheaths have been reported to cause granulomatous reactions at the site of needle entry.[2, 7]

Vascular complications of catheterization

These may include the following:

  • Accelerated atherosclerosis

  • Arteriovenous fistula

  • Avulsion of artery

  • Bleeding

  • Compartment syndrome

  • Cutaneous infection

  • Delayed reflex sympathetic dystrophy

  • Digital ischemia

  • Hematoma

  • Perforation, laceration, dissection

  • Pseudoaneurysm

  • Vessel spasm

  • Subcutaneous granulomatous reaction (hydrophilic coating)

  • Subacute and delayed occlusion

  • Transient vocal cord paralysis

 

Periprocedural Care

Equipment

Equipment for cardiac catheterization

Various instruments are available for arterial access for cardiac catheterization. The basic components include a needle, wire, and sheath. The specifications of each of these components vary considerably, making it vital to familiarize oneself with characteristics that allow successful access.[8]

A tiny skin incision at the site of the needle entry helps prevent damage to the sheath from skin friction and facilitates insertion of the sheath dilator .

The needle varies in length from approximately 2-5 cm and in diameter from 18-21 gauge. The needle bevel should also have a gentle curve so that it allows for easy entry of the wire.

The supplied wires are usually 30-50 cm in length and often have floppy tip and a more rigid shaft. Wires with a straight tip or small angulations are best suited for the radial and brachial artery, as J-tipped wires are often difficult to advance from the sheath into the proximal radial artery.

The most common sheath sizes for radial intervention are 5F-7F. The sheath may be 10 or 21 cm in length.[2, 7] Some cardiologists prefer the longer sheaths to minimize artery spasms. A sheath with a sidearm is preferable since it permits delivery of heparin and vasodilators.[3, 9, 10]

Regardless of the artery used, it should ideally be entered during the first needle stick. Repeat attempts induce trauma and spasms. Prior to needle entry, the pulse should be palpated and the site of entry marked. The needle entry site should be about 2 cm proximal to the radial styloid, as this will avoid radial artery bifurcation.[2, 7]

Lidocaine (1-2%) should be injected superficially around the artery. It may be combined with a tiny amount of nitroglycerin to help promote arterial vasodilatation. Arterial puncture is usually performed with a 21- or 22-gauge needle. Once blood flow is seen in the needle, it should be advanced a few millimeters. The plastic cannula is then advanced over the needle into the artery, and the needle is withdrawn.

Next, a small-caliber wire (0.018 to 0.025-inch diameter) is advanced through the cannula into the artery, and the cannula is removed so that a sheath with a tapered tip can be inserted over the wire. In some cases, the wire may not pass easily into the artery because of abnormal anatomy, vessel tortuosity, or spasm.[2, 7] Common causes of wire resistance include abnormal anatomy, tortuosity of the vessels, and spasm. If resistance occurs, the wire must be threaded under fluoroscopic guidance.

Catheter selection

The type of any diagnostic or interventional procedure is strongly influenced by the site of arterial access. Specific catheters for left and right radial approaches are available, although femoral or universal catheters can usually be used in the radial approach without difficulty. In some cases, a short JL curve and/or longer JR curve may be needed for procedures performed from the right radial artery.

Some experts indicate that a benefit of the universal catheter for coronary angiography is the ‘‘one-pass’’ technique, which results in less vessel spasm, shorter duration of procedure, less instrumentation, and lower equipment costs. Success rates associated with current universal catheters for diagnostic coronary angiography range from 96%-98%.

The chief disadvantage of the universal catheter is the steep learning curve. Variability in coronary and radial artery anatomy can complicate use of the universal catheter. One may have to utilize certain techniques to successfully use the universal catheters in patients with anatomic abnormalities. In some cases, asking patients to hold their breath can help align the catheter.

Although the small radial artery lumen diameter limits the arterial sheath size (5F-7F), balloons and stents are now available that permit aspiration of thrombus, treatment of lesions at bifurcation and the coronary ostia, and rotational atherectomy. Catheters and guides available for radial artery catheterization include the Castillo curves, Sones catheters, modified venous graft catheters, and internal mammary arterial catheters. A meta-analysis of trials indicated that radial access lowered mortality and improved safety.[11]

Accessories

After the procedure in the groin, a heavy pressure dressing is applied. For the wrist, most cardiologists recommend immobilizing the wrist with a splint for the first 24 hours. This helps prevent excessive wrist motion and bleeding. The splint should be worn for the first night, as people tend to move the wrist spontaneously. The splint also helps protect the site of needle puncture.

Like the FemoStop devices (St. Jude Medical Systems, Inc, St Paul, MN) used for the groin, a number of wristbands can be used to obtain hemostasis in the wrist. These 2- to 3-inch–wide bands are applied after the procedure is over and provide firm compression to the puncture site. Once the band is placed, the fingers are assessed for capillary refill and color to ensure that the band is not too tight. The band offers security from external trauma and can be adjusted by the patient. It is worn for the first 12 hours.[2, 7]

Sheaths

Several sheaths are available for use in the radial/femoral artery. Because of the tendency of the radial artery to spasm when manipulated, longer sheaths are often used. Some of these sheaths are available in a single- or double-dilator setup. The major advantage of the double-dilator setup is the presence of a tapered atraumatic tip, which is less likely to lacerate the artery. However, these sheaths have a transition between the first and second dilator, which can often cause resistance at the skin incision. The single-dilator system with less transition may be more traumatic to the skin and the artery at the insertion site. Several manufacturers are in the process of developing sheaths specific for the radial artery. These newer prototypes include sheaths that can be dilated several sizes and have a porous sheath equipped for administration of antispasm medication.[12]

Patient Preparation

Patients need to fast after midnight, but some laboratories allow the patient to have a light liquid breakfast.

Vital signs are obtained once the patient arrives to the laboratory.

The patient’s entire hand and arm up to the shoulder is prepared and draped in the usual sterile fashion. In addition, one of the groin areas (usually the right groin) should also be prepared and draped in case the radial artery access fails or there is an urgent need for placement of a transvenous pacemaker or an intra-aortic balloon pump.[13]

A suitably sized intravenous line should be placed in the contralateral arm, and the blood pressure cuff is usually placed on the leg. If the intravenous line is to be inserted in the same arm as the radial artery cannulation, it needs to be inserted proximal to the wrist or preferably just below the elbow.

The wrist should be slightly hyperextended with a rolled towel underneath the joint for support. A pulse oximeter is placed on the ipsilateral index finger or thumb. Extension tubing can be used between the catheter and the injection manifold so that the operator can move farther from the x-ray source.[2, 7]

Clothing (other than hospital gown), jewelry, bracelets, and rings should be removed prior to the procedure. These items must be documented and stored securely.

Premedication of the patient

Irrespective of the route of access for cardiac catheterization, the patient must be medically prepared. The procedure must be explained to the patient and an informed consent must be obtained. Most cardiologists do not administer prophylactic antibiotics prior to the procedure. Routine premedication is often used, but some laboratories prefer to administer sedatives during the procedure. The two most commonly used sedatives used include midazolam (1-2 mg IV) and fentanyl (25-50 µg IV every 30-45 minutes).

Medications used for cardiac catheterization are not standardized. Most cardiologists use combinations of medications based on experience.[2, 7] Some degree of sedation is usually administered irrespective of the access approach. Sedation is required when performing transradial catheterization. The introduction of the dilator and sheath is often painful. Conscious sedation is often the choice of anesthesia, with a dedicated nurse to monitor the patient. Many operators find fentanyl (25-50 µg IV every 30-45 mins) and/or midazolam (0.5-1 mg IV every 30-45 minutes) satisfactory.

Since the radial artery is subject to rather intense spasm, which can be painful to the patient and makes sheath and catheter movement difficult, several drugs may be administered to prevent or relieve the vasospasm. The typical medications used include verapamil, nitroglycerin, lidocaine, adenosine, and papaverine. These medications are administered during sheath insertion and removal or whenever radial spasm is suspected. Most operators routinely wipe the wire with a papaverine-soaked sponge before insertion. Adenosine is a potent vasodilator, but the cost of the medication is a limiting factor.

Anticoagulation is necessary during cardiac angiography via all access routes. Heparin 5,000-10,000 units is administered to prevent thrombus formation. The heparin is rarely reversed at the end of the procedure, primarily because it has a short half-life.

Medications and doses used during cardiac catheterizations are as follows:[2, 7]

  • Nitroglycerin 200 µg/mL (administered via the radial and brachial artery)

  • Verapamil 500 µg/mL (administered via the radial artery)

  • Lidocaine 2% 20-mg aliquots (administered via the radial artery)

  • Papaverine wipe on (radial)

  • Heparin 5,000-10,000 units

  • Fentanyl 25-50 µg IV prn every 30-45 minutes (transradially, 5 mg IV PRN every 5-15 minutes)

  • Midazolam 0.5-2 mg/mL IV prn every 15-30 minutes

Anesthesia

See Premedication of the patient.

Positioning

For both radial and femoral artery catheterization, patients are placed supine. The arms are tucked at the side of the bed for femoral artery access. For radial artery access, the nondominant arm is used and is usually abducted to about 45° to allow for access.

Monitoring & Follow-up

Once the procedure is complete, most cardiologists remove the intra-arterial lines without confirming anticoagulation parameters. Even in patients in whom GPIIb/IIIa inhibitors and/or thrombolytics have been administered, sheaths can be removed and hemostasis obtained with manual compression or a hemostatic device. For both radial and femoral artery access, the hand or feet are assessed for perfusion and capillary refill. In most cases of radial artery cannulation, the patient can ambulate 1-2 hours after sheath removal or whenever the sedation has worn off. Patients who undergo femoral artery access are asked to remain on bedrest for a minimum of 6-8 hours.

After discharge, all patients are asked to avoid excessive use of the involved hand for 24 hours or to refrain from walking until the following morning. Any activity that causes excessive flexion or extension of the wrist/hip is not recommended. The bruising that is common after the procedure usually disappears within 7-10 days.[2, 7]

 

Technique

Approach Considerations

Anatomic considerations

Femoral artery

The femoral artery is a continuation of the external iliac artery and is located just below the inguinal ligament. Here, the common femoral artery gives off the superficial femoral and profunda femoral arteries. The femoral artery is usually easily palpable at the groin and widely used for arterial access. When accessed for interventional procedures, the artery should ideally be cannulated below the inguinal ligament so that manual pressure can be applied to obtain hemostasis after the catheters and sheath are removed. Cannulation too proximal complicates manual compression because the artery dives into the pelvic cavity (ie, retroperitoneal space) and is covered by the firm inguinal ligament.

Location of femoral artery in relation to the nerv Location of femoral artery in relation to the nerve and vein. It is important to make the needle puncture below the inguinal ligament so that the vessel can be manually compressed.

Aortic arch

The aortic arch gives of the right innominate, left common carotid, and the left subclavian arteries. The right innominate artery gives off the right common carotid and then becomes the subclavian artery. The subclavian arteries become the axillary arteries as they pass under the axilla. In the axilla/shoulder, the arteries become the brachial arteries, which then divide just below the elbow into the radial and ulnar arteries. In rare cases, a radial artery may originate from the brachial artery in the upper arm. Thus, when performing a radial artery cannulation, the anatomy should be reviewed before passing any catheters or guidewires.[7, 14]

Brachial artery

The brachial artery courses down the medial and inner aspects of the upper am. As it approaches the elbow, it becomes slightly superficial and is very close to the median nerve. Distal to the elbow, the brachial artery travels under the supinator and pronator radii teres. At this junction, it divides into the ulnar and radial arteries.[2, 7]

Radial and ulnar artery

In most patients, the radial artery originates from the brachial artery just below the level of the elbow crease. At this point, it passes laterally along the forearm until it reaches the wrist. In the mid forearm, the artery runs between the flexor carpi radialis and supinator longus tendons. When it reaches the wrist, the radial artery is easily palpated above the trapezium and scaphoid bones and the external lateral ligament.

Radial and ulnar arteries. Because of the tortuosi Radial and ulnar arteries. Because of the tortuosity of the radial artery, the wrist needs to be extended prior to catheterization.

If cannulation of the artery is attempted too distally, the reticulum will be encountered, and the artery is often branched at this point. It is important, therefore, to attempt cannulation approximately 2-3 cm proximal to the flexion crease of the wrist.

At the level of the hand, the radial artery traverses the space between the metacarpal bones of the thumb and index finger and enters the palm. The vessel then crosses the base of the metacarpal bone of the little finger and joins with the deep communicating branch of the ulnar artery, resulting in a patent deep palmar arch. The superficial palmar arch is made by communication of the ulnar artery with the superficialis branch of the radial artery.[15]

The ulnar artery also branches off the brachial artery and passes along the medial aspect of the forearm. At the level of the wrist, it divides into two branches that join the radial artery and its superficial branch to form the deep and superficial palmar arches. Despite good ulnar and radial pulses, an incomplete palmar arch is observed in 10%-20% of patients.[2, 7]

Any patient with radial artery dominance (ie, an abnormal Allen test result) should not undergo cannulation of that artery. In addition, patients who have ulnar artery dominance tend to have a higher incidence of radial artery access failures with cannulation.[2, 7]

Ulnar artery

The ulnar artery has rarely been used for cardiac angiography. The ulnar artery is usually smaller, and access can be difficult. Moreover, the position of the ulnar artery at the wrist is inconsistent, and compression for hemostasis is also a problem.[16]

Right or left radial artery

The right radial artery is often selected over the left, as it is easier for the operator to perform the procedure. The left radial artery can be used, but, often, the laboratory setup complicates access. Other reasons why one may select one radial artery over the other is the presence of a left internal mammary graft (which is easier to access via the left radial artery) or the possibility of future use of the radial artery as a bypass graft.

In short obese individuals, the aortic arch and descending thoracic aorta are often easier to access from the left radial artery than the right.[17] In addition, access to the branches of the aortic arch are also easily accessed from the left radial artery.[18]

Femoral artery approach

The percutaneous femoral approach for cardiac catheterization has been widely used and is clearly well established. Unlike the brachial artery approach, the femoral artery approach does not require an arterial cutdown or repair. In addition, the technique can be performed repeatedly in the same patient after a suitable interval. The femoral artery is usually palpable and allows for easy access. The femoral approach is clearly the method of choice in a patient with absent or diminished radial and brachial pulsations, when the brachial or radial approach has been unsuccessful, and when large-caliber catheters are used.[19]

The transfemoral route for cardiac catheterization and intervention procedures has stood the test of time and is considered the criterion standard. It has gained universal acceptance because of the following reasons:

  • Long history of use and predictably

  • Technically easy to access

  • Enables use of larger sheaths and other equipment

  • Complications are well known

  • User experience is extensive

Several closure devices that provide postprocedural hemostasis are available and enable patients undergoing femoral access to ambulate soon after completion of the procedure. Nevertheless, the closure device fails in some cases, resulting in femoral arterial bleeding. Use of collagen-based closure devices often limits access to the groin area for several weeks and even months afterward.[2, 7]

The following are disadvantages of the femoral approach:

  • Prolonged bedrest that may range from 4-8 hours; the larger the sheath, the longer the period of bedrest

  • Associated with adverse effects such as urinary retention, femoral nerve neuropathy, and back discomfort

  • Vascular complications such as bleeding, femoral artery pseudoaneurysm, and arteriovenous fistula[20, 21]

  • Damage, dissection, or occlusion of the femoral artery

  • Cholesterol emboli

Radial artery approach

Transradial cardiac catheterization was first used by Campeau et al in 1989 to perform cardiac catheterizations.[14] The technique was successful in most patients, but pulse loss was evident in some patients at the end of the procedure. The first percutaneous transluminal coronary angioplasty (PTCA) performed transradially was done in 1993. Since then, the equipment and procedure have been refined so that radial access is now widely used by cardiologists universally for both diagnostic and therapeutic purposes.[8]

Advantages of the radial approach are as follows:

  • Dual blood supply to the hand, which minimizes the potential for hand ischemia

  • Access for patients with aortoiliac disease or aortic aneurysm

  • Does not require prolonged bedrest postprocedure, which is desirable in the patient with congestive heart failure, dyspnea, or back pain

  • Easy to compress and achieve hemostasis

  • Fewer vascular complications compared with the femoral approach

  • Patient preference and acceptability[8]

There are some disadvantages to a radial approach, and most of these relate to the small-vessel caliber or tortuosity. The technical difficulties with radial artery access include the following:

  • The radial artery is much smaller in diameter (averaging about 2-3 mm) than the femoral artery (5-10 mm)

  • Cannulating the radial artery involves a steeper learning curve than the femoral approach

  • A smaller sheath and catheter (4F-6F) can be accommodated than in the femoral approach

  • Vessel spasm is common

  • Guide insertion can be difficult and requires time and patience

  • Many cardiologists and radiologists are not completely familiar with the equipment and radial artery anatomy and, thus, are often reluctant to try a new approach

  • Increased procedure time and radiation exposure to the patient and cardiologist compared with the femoral approach

A radial artery approach may not be appropriate in all patients. Contraindications include the following:

  • Patients with an abnormal Allen test result[10]

  • Patients who have intra-aortic balloon pump counter pulsation (IABP) are not candidates for radial artery catheterization

  • Certain individuals may need larger devices for percutaneous coronary intervention, and the radial artery may not allow for insertion of large sheaths

  • Any patient with known Buerger disease, Raynaud disease, collagen vascular disease, or evidence of vascular disease of the upper extremity should not undergo radial artery cannulation

  • Certain congenital abnormalities of the radial arteries or subclavian vessels

  • Extreme tortuosity or severe atherosclerosis (ie, may preclude safe radial artery cannulation)

  • Patients in whom the radial artery may be considered as a conduit for coronary artery bypass grafting or for a dialysis graft[2, 7]

The transradial approach is rapidly becomig the standard approach in many hospitals.[22] This approach has been associated with fewer complications than that with the femoral artery approach, a shorter immobilization period, and a shorter length of hospital stay. Furthermore, a large study showed that the radial artery approach was associated with similar outcomes to those of the femoral approach but with a lower rate of complications—even for complex coronary lesions.[23]

Brachial artery approach

The brachial approach is rarely used and usually requires a cutdown. The incision is made just above the crease of the elbow, and the brachial artery and vein are isolated. Brachial arterial access is a viable option in patients who have iliac or femoral arterial disease. The technique is also suitable in very obese patients in whom the groin approach may be difficult for obvious reasons.[10] Another advantage occasionally cited for the direct brachial approach is use of a single catheter (Sones catheter) for left heart and coronary artery catheterization.

Brachial artery in relation to median nerve. Acces Brachial artery in relation to median nerve. Access to the brachial artery for catheterization usually requires a cutdown.

The brachial artery cannot be used more than 2-3 times for cardiac catheterization. Rarely, the brachial artery approach may limit blood flow to the hand, necessitating immediate removal of the catheter

Radiation exposure

Radiation exposure is unavoidable regardless of the access route selected. There is evidence that using the radial artery to perform coronary interventions often results in more radiation exposure than the femoral artery approach, and this is greater when using the right arm than the left. Radiation exposure generally decreases as operator experience increases.

Other considerations

Difficult guidewire entry

After successful arterial access is achieved with the needle, it is sometimes difficult to advance the guidewire. This may be related to the following:

  • Tortuosity

  • Vessel spasm

  • Radial artery stenosis or occlusion

  • Guidewire may be in a side branch

  • Abnormal radial artery takeoff from brachial artery

  • Wire abutting the wall

In such scenarios, the following may be attempted:

  • The use of fluoroscopy for guidance

  • Rotation of the needle to change bevel angle

  • Use a smaller diameter hydrophilic wire

  • Administer a vasodilators intra-arterially through the needle and then attempt to advance the wire

Difficulty removing sheath

This is rare but can occur in small patients, especially women, and often results from intense spasm. If this occurs, the following may be tried:

  • Administer vasodilators prior to removal

  • Administer pain medication

  • Gently rotate the sheath during removal while applying distal skin traction

Sheath removal

Sheath removal is not a problem from the femoral artery. However, the sheath should not be removed from the radial artery without preparation. In many cases, when the sheath is removed, the radial artery goes into spasm. Thus, vasodilators, lidocaine, and sedatives should be available.

Hemostasis

Prior to the availability of hemostatic devices, the cardiologist or nurse had to apply manual pressure to the groin for 30-45 minutes to obtain hemostasis postprocedure.[2, 7] Now, there are several methods of obtaining hemostasis at the catheter insertion site. The choice of method to obtain hemostasis is strictly personal preference of the cardiologist.

Difficulties of transradial intervention

Unlike the femoral artery, which is large and easily palpated, the radial artery is small, and the pulsations are not strong. The first needle stick is done with care because a miss usually results in vessel spasm. In such cases, there are several options, as follows:

  • Delay the procedure for 2-30 minutes to allow the spasm to resolve

  • Attempt cannulation at a proximal site

  • Administer nitroglycerin (sublingually, intravenously, or topically on the hand)

  • Ask the patient to open and close hands for a few minutes

  • Use the brachial artery, contralateral radial artery, or femoral artery

In some cases, an adequate radial pulse may be palpated, but there is no return of blood in the needle lumen upon entry into the vessel. In such scenarios, the physician needs to consider the possibility of disease of the radial artery or that the pulse is due to the ulnar blood flow.

In some cases, the radial artery may be very mobile and may shift during needle entry. In these cases, the artery may have to be stabilized between the fingers while trying to cannulate it with a needle.[2, 7]