Use of Vascular Ultrasound Guidance in Obtaining Access for Transradial Coronary Angiogram in Patients With Advanced Shock

Introduction 

Following the first reports of radial coronary angiography by Lucian Campeau in 1989 and radial percutaneous coronary intervention (PCI) by Ferdinand Kiemeneij in 1992, the proportion of radial procedures has continued to rise worldwide, with radial access now replacing femoral access as the dominant access site for PCI in some countries.^1-3 Worldwide, an estimated 20% of procedures are performed by this route (29%, if the U.S. is excluded from the estimate).³

North America has a major divergence, between Canada at 50% and the U.S. most recently reaching only 15-20% transradial utilization.^3-5

Several recent randomized trials have shown the superiority of radial access over traditional femoral access in terms of lower bleeding, vascular complications, higher patient satisfaction, and in the subset of patients with ST elevation myocardial infarction (STEMI), lower mortality in the radial group.^6-9 Despite these demonstrated advantages, resistance to adopting this access strategy remains.

Reasons for this may include the learning curve associated with performing a new technique, hesitancy in performing complex interventions, concomitant use of support devices that require large-bore arterial access, and the belief that radial access may be less desirable in patients with shock, as getting access may be challenging when the radial pulse is weak or absent. Also, few randomized trials that compared radial and femoral access included shock patients. 

An alternate perspective could be that radial access can give an independent access for the coronary intervention, with its known advantages, and femoral access can be used for support devices, if and when clinically indicated. The radial artery is relatively small as compared to the femoral artery and due to vasoconstriction in shock, it can be difficult to palpate. Also, with advanced short- and long-term left ventricular assist devices like extracorporeal membrane oxygenation (ECMO), Impella, and other left ventricular assist devices (LVADs), the pulsatility may be minimal or none, hence making radial access challenging. 

Vascular ultrasound is safe, cheap, and freely available in most cath labs, and is being recommended more and more for obtaining central access. The radial artery is very superficial and does not have a major vein or nerve in the vicinity, making it relatively easy to identify on the ultrasound. With this case as an example, we describe the technique of using ultrasound in shock patients and simple troubleshooting steps.

Case

A 49-year-old male with hypertension, hyperlipidemia, insulin-dependent diabetes, and newly found severely reduced systolic function (ejection fraction 10-15%) underwent two-vessel coronary artery bypass surgery (CABG) with left internal mammary artery (LIMA) to the left anterior descending artery and a reverse saphenous vein graft to the first obtuse marginal artery. His immediate postoperative course was uncomplicated; however, on postoperative day six, the patient had sudden cardiac arrest with ventricular fibrillation as the initial rhythm. Advanced cardiovascular life support (ACLS) failed to achieve hemodynamic stability. Veno-arterial ECMO was initiated percutaneously via the right femoral vessels and the patient was taken back to the operating room. The flow in the venous cannula was suboptimal and therefore a cannula directly into the right atrium was placed. Doppler flow suggested likely functioning grafts and there was no pericardial tamponade. The chest was closed and the patient was transferred to our hospital for advanced surgical and ECMO care. 

On arrival, patient was on epinephrine, vasopressin, dobutamine, amiodarone, and lidocaine drips. About six hours later, flow on the ECMO decreased to 3 L and central venous pressure increased to 18 mmHg. Due to this hemodynamic instability, trans-esophageal echo was performed which showed tamponade physiology. The patient was taken to the operative room again and after opening the chest, 3-3.5 L old and new blood was removed from the pericardial space. The LIMA anastomosis site was bleeding (likely due to the repeated chest compressions), and was secured with three sutures. Intraoperatively, all four chambers of the heart appeared visually dilated and therefore, direct unloading of the left atrium by placing another cannula in the pulmonary vein was done. During the surgery, the patient had numerous episodes of ventricular fibrillation, for which direct intracardiac massage and cardioversions were done. The patient was placed on a procainamide drip. Bleeding was stopped, stable flow on ECMO was obtained, and the patient’s chest was closed again.

The reason for such refractory hemodynamic and electrical instability was still unclear. Concern was raised as to whether his mammary artery graft was unintentionally attached to the diagonal branch, leaving a critical left main and proximal left anterior descending artery stenosis unvascularized. He was therefore referred for urgent coronary angiography. The patient had no palpable pulses due to the continuous flow of the ECMO. Multiple blind attempts to place radial arterial lines in the intensive care unit (ICU) had failed.

The right radial artery was identified using two-dimensional (2D) imaging on vascular ultrasound. Color and Doppler flow showed continuous non-pulsatile flow. Under the ultrasound guidance, the radial artery was punctured on the first attempt and a 6 French sheath was placed. Coronary angiography was performed without difficulty and showed significant, old disease in the patient’s native vessels and patent grafts. No intervention was required and patient was safely transported back to the ICU. With intensive support, he stabilized and eventually underwent left ventricular assist device (LVAD) placement.

Discussion

This patient posed several challenges in obtaining access for the coronary angiography. The right femoral artery had an ECMO outflow cannula. The left femoral had several unsuccessful attempts at placing arterial line during cardiopulmonary resuscitation (CPR). Both wrists had marks of several failed attempts of placing an arterial line in the ICU. 

Gaining access on the first attempt is optimal, as repeated arterial trauma increases the risk for spasm. Therefore, careful vessel palpation and planning of the arteriotomy puncture are critical to successful transradial access (TRA). The arteriotomy should be approximately 2 cm proximal to the radial styloid in order to avoid the bifurcation and diminutive distal vessel. 

Two-dimensional images of vascular ultrasound can help localize the radial artery with potential to size, which may further aid in deciding the sheath size. Color flow helps in separating the vessel from confounding nearby structures (Figure 1). Pulse wave Doppler of an artery typically demonstrates a pulsatile waveform in normal, hemodynamically stable patients (Figure 2). In patients with ECMO or LVAD support, the radial artery is easy to locate as a non-compressible vessel on two-dimensional images; however, the Doppler has a continuous non-pulsatile flow (Figure 3). 

Once location, patency, and size of the radial artery are confirmed, radial access is obtained using a regular 21 G micropuncture needle. The needle can be seen advancing on the 2D ultrasound images and appropriately directed as needed. 

In this patient, radial access was obtained without difficulty and the coronary angiography was performed without complications. The patient’s grafts were attached appropriately as reported and were widely patent. This case demonstrates that ultrasound was quick and effective in accessing the radial artery, the same artery that had failed multiple blind attempts.

In multiple randomized trials and meta-analyses, real-time ultrasound guidance has been shown to reduce complications, number of attempts, and time to access in central venous cannulation.^10-11 Routine use of ultrasound guidance has been recommended by the National Institute of Clinical Effectiveness (U.K.) and Agency for Healthcare Research and Quality (U.S.) for central venous line placement^12-13 and has become the standard of care.

In their single-center registry experience with radial access in cardiogenic shock patients, Rodriguez-Leor et al¹⁴ showed that the transradial approach is a viable approach in up to two-thirds of patients with cardiogenic shock requiring PCI, resulting in safe and positive outcomes. Patients who underwent PCI with TRA had a lower incidence of serious access site complications, and in the multivariate analysis, TRA was associated with a lower risk of mortality compared with transfemoral access. One of the main factors preventing the use of TRA in these patients was the absence of radial pulse. 

Vascular ultrasound may help negotiate the challenge posed in radial access in conditions where the pulse is weak or absent. Use of ultrasound guidance may increase access to the benefits of performing the PCI via radial access, thereby exposing patients to one less femoral artery puncture. In cases where percutaneous hemodynamic support devices are needed, radial PCI has been shown to be feasible. Bell et al described a case series in which patients developing cardiogenic shock had PCI performed via the transradial route, with hemodynamic support provided by the Impella device. All cases were performed successfully,
with no vascular complications.¹⁵

One of the potential concerns of ultrasound-guided access can be that it may “slow down” the procedure, which may be detrimental in emergent conditions. However, there is a learning curve to all procedures. Therefore, ultrasound-guided access can be attempted in non-emergent, routine cases first and then taken a step further, like a non-pulsatile artery in a LVAD patient. Once the operator gets comfortable with technique, it may actually turn out to be time saving.

Conclusion

Ultrasound is traditional method of obtaining vascular access; however, puncture of smaller
vessels is difficult. Ultrasound guidance may have the potential of providing a safe, effective, and quick way of radial artery access in conditions where the pulse is weak or absent in patients with advanced shock, but this needs to be tested in a larger study.

This case report received a double-blind review from members of the Cath Lab Digest editorial board.

Disclosures: Pradeep K. Yadav, MD, Giselle A. Baquero, MD, and Ian C Gilchrist, MD, have no conflicts of interest regarding the content herein.

The authors may be contacted via Pradeep Yadav, MD, at pyadav@hmc.psu.edu.

References

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