Complexities of radial interventions simplified- An algorithmic approach to troubleshooting
While an algorithmic approach for trouble shooting technical challenges in other arenas of interventional cardiology like chronic total occlusion intervention has been previously published, such an algorithmic approach for technical challenges in transradial approach (TRA) is not available. In a recently published review article in Indian Heart Journal, Sawant et al have presented a systematised algorithmic approach for identification and management of TRA related challenges and complications.
The review discusses the relevant anatomical aspects of radial artery and mentions how the radial artery negotiates muscles and tendons of the forearm and arm and is predisposed to a higher incidence of loops and turns.
1. Algorithm for radial artery spasm:
When it comes to radial artery spasm, the saying "an ounce of prevention is worth a pound of cure" could not be more apropos. Ways to prevent radial artery spasm are:
1. Adequately relaxing and sedating the patient prior to attempt at access.
2. Minimizing attempts, especially if the vessel is small in caliber or difficult to palpate.
3. Point of care ultrasound and counter-puncture technique by transfixing the radial artery.
4. If spasm occurs prior to obtaining access, waiting for the spasm to abate and subcutaneous administration of nitroglycerin at near the access site are potential solutions
5. Smallest caliber sheaths with hydrophilic coating and a tapered tip lower the occurrence of spasm.
6. Radial cocktail of Verapamil and Nitroglycerin has been shown to be most effective as a spasmolytic.
7. In patients with anticipated spasm nitroglycerine can be mixed with local anesthesia for local infiltration before puncture can be attempted.
8. The various steps to manage once a spasm has set-in are shown in figure 1.
2. Algorithm for tortuosity in the arm:
1. Once resistance is encountered in advancing the catheter, first step is to take a contrast injection to define the cause of resistance.
2. On confirmation of bend/loop, next step is downsizing the 0.035" wire to an 0.025", 0.018" or 0.014" wire.
3. If unable to advance the catheter over the lower profile wire, a maneuver called "straightening the loop" is performed. This involves advancing the lower profile wire as far beyond the loop as possible and the catheter as far into the loop as possible. Pulling the entire assembly back with slight rotation opens the loop and straightens the segment.
4. Balloon assisted tracking (BAT), by using a partially inflated balloon protruding out from the catheter allows for negotiation of tortuosity when the simpler methods described earlier fail.
3. Algorithm for tortuosity in the subclavian, innominate and aortic arch
Negotiation of the obtuse angle of the innominate aortic junction is unique to TRA. Due to the risk of injury to large bore vessels in the thorax, careful procedural consideration is necessary. The simplest way to negotiate a simple loop or tortuosity is have the patent take a deep breath while advancing the wire under fluoroscopic visualization. Further steps of algorithm are shown in Figure 2.
4. Algorithms for catheter kinks and knots
The first sign of a catheter kink is the loss or dampening of the arterial pressure tracing. The algorithm for managing a kink or twist is:
(a) Untwisting of the catheter knot by rotation in the opposite direction.
(b) External Fixation of the catheter at the level of the arm by inflation of a sphygmomanometer.
(c) Using a larger sheath
(d) Internal Fixation with femoral access and advancement of a 6Fr catheter into the innominate and snaring the proximal end of the kinked catheter fixates the catheter for untwisting at the wrist with gentle advancement of a 0.03500 hydrophilic wire through the catheter.
5. Algorithms for radial artery perforation
1. The perforated segment should be crossed meticulously with a guidewire using balloon assisted tracking and guide catheter tamponade is the recommended strategy.
2. Additionally, external compression with a sphygmomanometer cuff at the level of systolic blood pressure located slightly above the bleeding site is recommended.
3. If the perforation is not sealed by these maneuvers, urgent consultation with a vascular surgeon is recommended to avoid development of compartment syndrome.
When an unexpected event happens with potential for harm to the patient during a procedure, an interventional cardiologist is caught off guard. With a check list or algorithm, the situation can often be managed successfully. This paper provides radial operators algorithmic solutions to challenges encountered during TRI.
Source: Indian Heart Journal: https://doi.org/10.1016/j.ihj.2020.09.012