About 15% of diagnostic cardiac cath cases need right heart hemodynamics with their left heart cath. For these patients, it seems that the radial approach may be discouraged because of perceived venous access difficulties and a desire to use thermodilution 7 French (F) catheters. Since beginning our radial program, we have incorporated the access of a large forearm or brachial vein with radial artery access to perform the complete left and right heart cath with only minor modifications. The use of the arm for both right and left cath permits performance of the procedure from the same sites (roughly) and post cath care of only the arm, eliminating concern about leg site bleeding. While some operators are comfortable with internal jugular vein access for ICU patients, this access in the cath lab is cumbersome. Use of the forearm venous system (Figure 1) facilitates easy pulmonary artery catheterization, temporary pacemaker placement, myocardial biopsy (with a 7F sheath), and other transvenous procedures.
When considering the venous anatomy of the arm, two concepts should be kept in mind. Medial is better than lateral and higher is better than lower. The medial position of the brachial vein makes its use better than the lateral cephalic vein, because the cephalic vein forms a ‘T’ junction or acute angle at the point where it joins the subclavian vein. This bend can be difficult to negotiate without resorting to coated or angioplasty guidewire assistance. Secondly, the higher in the arm one goes, the larger the vein. The implications of this are obvious.
Easy Vein Access: Pre Cath IV
To access the brachial vein, application of a tourniquet several centimeters above the elbow facilitates the identification of a suitable vein. Our nurses insert a 20g Angiocath (Becton, Dickinson and Company) in a medial vein whenever possible. After insertion, the nurse then seals the Angiocath with a needless valve cap and secures the position with a small amount of tape. This part of access can be performed in the prep area or on arrival to the cath lab. While the antecubital veins may be most available, more distal veins can also be used. If there are no visible superficial veins, one can use ultrasound imaging above the elbow to identify deep veins in a manner similar to peripherally inserted central catheter (PICC) line placement.
The sheath insertion technique involves the same set up as for radial artery access. The arm is prepped from fingers to above the elbow. Sterile draping is performed per lab routine, but maintaining an open access area to the forearm vein Angiocath insertion location. To maintain best sterile conditions, we have a second set of towels and gloves ready to be used after exchanging the Angiocath for a venous sheath.
Simple Steps for the Sheath
The following are the simple steps needed to insert a venous sheath into the arm vein.
- Step 1: Inject local anesthesia at the entry site, adjacent to the Angiocath.
- Step 2: Remove the cap and introduce a 0.018” micropuncture guide wire. Alternatively one can puncture the cap on the intravenous catheter with the access needle.
- Step 3: Pass the guidewire through the Angiocath into the vein. Figure 2a shows contrast injection through the Angiocath to see the vein, where we had a minor resistance to wire advancement. As seen, the venous valves can interfere with smooth wire passage. As with all guidewire advancement, if resistance is encountered, change wire angle, wire tip bend, or use angiography to see what the problem is. Occasionally, a hydrophilic angioplasty guidewire may be needed. Figure 2b shows the wire in correct position in the vein.
- Step 4: After the guidewire is well into the vein, remove the Angiocath and make a small nick in the skin. Inject more lidocaine if needed.
- Step 5: Insert the vascular sheath, inserted via the same technique as for the arterial sheath.
- Step 6: Remove the wire and dilator. Flush the sheath with saline. Secure the sheath with a Tegaderm (3M) dressing (Figure 3). There is usually no need for antispasmodic medication, although nitroglycerin (NTG) would be the agent of choice. If performing only a right heart cath, heparin is not necessary. Because of the low blood flow in the vein, only gentle aspiration should be applied to the sheath before flushing. Figure 4 shows arterial and venous access sheaths before the Tegaderm dressings to secure sheath movement have been applied. This approach is particularly helpful in obese patients in whom both femoral arterial and venous access would be difficult, if not impossible.
After securing the sheaths, the arm is then brought over to the right side of the patient. From this position, the right heart catheter can be introduced, followed by standard radial catheter advancement techniques.
Overcoming Difficult Access: Ultrasound-Facilitated Venous Access
Venous access may be difficult to obtain in patients who have altered anatomy, obesity, or prior surgical procedures. Venous access may be achieved with an ultrasonic direct visualization transducer (Site~Rite, Bard Access Systems).
The technique of sheath insertion is easier than arterial access. We usually use a 5F venous sheath that accepts 5F balloon-tipped wedge catheters. This is a pediatric catheter, but also has length sufficient for adult patients. In some very tall patients, it may not be long enough to wedge reliably. In this case, if the wedge pressure is critical, we exchange for a 7F sheath and regular pulmonary artery flotation catheter. For the wedge catheter without thermodilution capability, superior/inferior vena cava and pulmonary artery saturations are collected along with an arterial saturation to compute an assumed Fick cardiac output.
When passing a catheter from the forearm, there are two primary courses the venous system may take. Veins on the medial (ulnar) side enter into the basilic vein that continues as the axillary and subclavian vein. This is a very straight course that can be traversed usually without fluoroscopy.
The second and less desirable course occurs with access from the radial side and some medial veins that pass laterally along the upper arm, forming the cephalic vein that will then enter the axillary vein to form the subclavian vein. This cephalic/axillary junction may form a 90-degree bend, challenging smooth catheter passage. Do not push the catheter against resistance. Under fluoroscopy, take a brief venogram to define the vessel course (Figure 5). A deep breath may straighten the vein, allowing catheter advancement. Sometimes, gentle saline flush during advancement makes catheter passage possible. If these maneuvers fail, placing a hydrophilic wire through the catheter may allow passage up the axillary vein and into the subclavian (Figure 6). On occasion, when experiencing difficulty negotiating venous valves or a T-junction, one can use an angioplasty 0.014” steerable guide wire through the catheter to maneuver into the correct vein system.
Once the catheter has reached the subclavian vein, it is easily passed through the right heart into the pulmonary artery, as done with other central venous catheters (Figure 6). Remember to deflate flow-directing balloons before pulling back into the smaller caliper veins, but otherwise, no special precautions are necessary.
At the conclusion of the procedure, the vascular sheath is removed and a pressure dressing is applied. Hemostatic devices used on the radial artery are not needed in the case of the low-pressure venous system. Venous arm access can increase the spectrum of cases done from the radial approach.
For your next right heart cath, consider this approach. Like the radial access, patients and staff will soon recognize its ease and benefits.
Disclosure: Dr. Kern reports that he is a speaker for Volcano Therapeutics and St. Jude Medical, and is a consultant for Merit Medical and InfraReDx, Inc.
- Kern MJ ed. The Cardiac Catheterization Handbook, 5th ed. Philadephia, PA: Elsevier; 2011.
- Kern MJ. Transradial 101 Handbook. 2011. Available online at http://teleflexhandbook.com. Accessed November 21, 2011.