No-reflow: distal drug delivery with standard PCI equipment
A practical guide to distal vasoactive drug delivery in no-reflow using standard PCI equipment when conventional intracoronary administration is insufficient.
When guiding catheter delivery fails in no-reflow
No-reflow is one of the most critical peri-procedural complications limiting the benefit of primary percutaneous coronary intervention (PCI).
Administration of specific vasoactive agents, such as adenosine, adrenaline, dobutamine, and nicorandil, into the microvascular bed may improve microvascular perfusion and treat no-reflow. Although intracoronary drug administration through the guiding catheter is the standard of care, delivery of the drug directly into the distal vascular bed may be more beneficial, especially in the presence of TIMI 0 flow. There are dedicated coronary infusion catheters for this purpose; however, they are not routinely available in most cathlabs.
Consequently, operators frequently resort to the off-label use of standard interventional equipment for distal drug delivery. This approach requires advancing the equipment into the distal coronary artery without guide-wire loss and ensuring safe, successful drug administration. Care must be taken during system preparation, and several important points must be addressed for a successful application.
Managing the hemodynamic consequences of coronary no-reflow
Every interventional cardiologist faces with no-reflow. The development of no-reflow can rapidly trigger cardiogenic shock in a STEMI patient who was hemodynamically stable at the beginning of the procedure.
Managing this clinical situation in the middle of the night, with a nurse and a technician, is not uncommon. Therefore, combating no-reflow requires the ability to use all available tools effectively.
A practical strategy for treating no-reflow
Distal vasoactive drug administration can deal with no-reflow in case of TIMI 0 flow.
Materials needed
- Coronary microcatheter
- Thrombus aspiration catheter
- Over-the-wire balloon
- Monorail balloon
All of this equipment can be used.
OTW balloons and microcatheters require an identical approach, whereas thrombus aspiration catheters and monorail balloons follow a similar rapid-exchange workflow.
N.B. : size of the trapping balloon needed is related to the French of the guiding catheter: a 2mm balloon for a 6F; a 2.5mm balloon for a 7F guiding catheher.
Method step-by-step
OTW Balloon / Microcatheter:
Clinical scenario: You have a work-horse wire in the coronary, and no-reflow develops. You decided to use a microcatheter or OTW balloon for distal drug delivery. You don’t have a wire extension.
- Prepare the vasoactive agent solution using a 10 or 20 cc syringe.
- Flush the microcatheter/OTW balloon gently with normal heparinised saline
- As the work-horse wire is short to exchange, first insert a trap balloon till the distal part of the guiding catheter. Inflate the balloon and trap the wire.
- Advance the microcatheter/OTW balloon till you hold the distal tip of the wire
- Secure the wire, deflate the trap balloon, and retrieve it
- Advance the microcatheter/OTW balloon to the preferred area of the distal coronary artery and then remove the work-horse guidewire
- Gently administer the desired dosage of the drug (at this point, contrast might be given if the distal coronary is wanted to be visualised to exclude thrombus or dissection)
- Check if the coronary flow is improved or not (if not, additional drug administration or another agent administration can be performed)
- Reinsert the work-horse wire, retrieve the microcatheter/OTW balloon into the guide catheter in a position where safe trapping can be applied.
- Insert the trap balloon again, trap the wire, and get the microcatheter/OTW balloon out of the guiding catheter
- Deflate and retrieve the trap balloon.
Monorail balloon / Thrombus aspiration catheter:
Clinical scenario: You have a work-horse wire in the coronary, and no-reflow develops. You decided to use a monorail balloon or thrombus aspiration catheter for distal drug delivery
As these two devices are monorail, their distal insertion is more practical than OTW Balloon / microcatheters. Monorail balloons must be perforated for distal drug delivery.
Device Preparation | ||
| Monorail balloon | Aspiration catheter |
1 | Flush the monorail balloon with heparinized saline gently (the balloon will be inflated) | Flush the aspiration catheter with heparinized saline gently |
2 | Gently perforate the balloon with a needle from 4 perpendicular areas (any standard syringe needle can be used) |
|
3 | Be careful not to disturb the balloon too much |
|
4 | Continue gently flushing, see the droplets of the saline, be sure there is no air bubble |
|
- Prepare the vasoactive agent solution using a 10 or 20 cc syringe.
- Prepare the monorail balloon / thrombus aspiration catheter
- Load the perforated monorail balloon / thrombus aspiration catheter over the work-horse wire while flushing with vasoactive agent solution continuously. Continue flushing gently until the insertion into the guiding catheter.
- Advance the perforated monorail balloon / thrombus aspiration catheter into the desired location of the distal coronary artery
- Gently administer the desired dosage of the drug (at this point, contrast might be given if the distal coronary is wanted to be visualised to exclude thrombus or dissection)
- Check if the coronary flow is improved or not (if not, additional drug administration or another agent administration can be performed)
- Retrieve the perforated monorail balloon / thrombus aspiration catheter out of the guiding catheter
Points of specific attention
- Maintaining wire position is essential across all techniques, and the implementation of specific maneuvers prevents its loss.
- When administering drugs or contrast agents, smaller syringes like 2 mL and 5 mL might provide a more comfortable distal infusion, especially when using a microcatheter/OTW balloon. However, the limited fluid volume is the main disadvantage of using smaller syringes.
- The distal drug administration system must be prepared in a manner that prevents air embolism during distal drug administration.
- Air bubbles may be aspirated into the system during the insertion and removal of these devices through the guiding catheter. Keeping this constantly in mind, it is recommended to check for bleeding and the absence of air after the devices are removed
A word from the reviewer
Slow/no-reflow phenomenon is a relatively common complication following percutaneous coronary intervention (PCI), particularly in the setting of ST-segment elevation myocardial infarction. Pathophysiologically, it is associated with microvascular obstruction and is linked to a larger infarct size compared with patients who do not develop this complication. Initial treatment typically involves the infusion of pharmacological agents through the guiding catheter. If coronary flow is not successfully restored, a more targeted distal drug delivery approach may be required.
This article elegantly demonstrates how materials readily available in virtually every catheterisation laboratory can be used to achieve effective distal drug infusion in a simple, rapid, and efficient manner. The authors extended the trapping technique, traditionally used in complex PCI for wire exchange (e.g., during rotational atherectomy or CTO interventions), to facilitate the successful delivery of drug-infusion devices such as microcatheters, over-the-wire (OTW) balloons, thrombus aspiration catheters, and “customised” monorail balloons. Special emphasis is placed on avoiding inadvertent air embolisation during the procedure which could further compromise coronary flow.
While a perforated monorail balloon or the aspiration catheter may be useful for emergency manual bolus administration, a dedicated microcatheter or an OTW balloon using the trapping technique described by the authors is preferable in hemodynamically stable patients or whenever prolonged and controlled drug infusion is required.
Disclosures
The expert declare no conflicts of interest to disclose.
Authors
No comments yet!