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Burr Entrapment – Case 1

Clinical Presentation

  • 72-year-old male who presented to the hospital with chest pain (CCS Class III) and was referred for staged PCI of the LM bifurcation.

Past Medical History

  • HTN, HLD, Former Tobacco Use, CAD s/p Multiple PCI’s
  • LVEF 15%

Clinical Variables

  • Prior Cardiac Catheterization: Distal LM 90-95% stenosis s/p successful PCI, mid LAD 90-95% stenosis s/p successful PCI, proximal LCx 50-60% stenosis, proximal RCA 80-90% stenosis.

Medications

  • Home Medications: Aspirin, Clopidogrel, Atorvastatin, Carvedilol, Lisinopril, Spironolactone, Furosemide
  • Adjunct Pharmacotherapy: Clopidogrel, Bivalirudin

Pre-procedure EKG

Angiograms

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Left coronary artery angiography
  • 70-80% calcified lesion in the left main (LM)
  • 50-60% in-stent restenosis in the proximal left circumflex (LCx)
  • 70-80% calcified lesion in the mid left anterior descending (LAD) artery with hazy appearance on angiography
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Left coronary artery angiography

  • 70-80% calcified lesion in the left main (LM)
  • 50-60% in-stent restenosis in the proximal left circumflex (LCx)
  • 70-80% calcified lesion in the mid left anterior descending (LAD) artery with hazy appearance on angiography
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Right coronary artery (RCA) angiography

  • 80-90% calcified stenosis in the proximal RCA.
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Impella was placed, followed by left coronary artery angiography.

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Pre-dilatation of the ostial LM lesion with a Trek NC 4.0/12mm balloon.

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Cutting balloon angioplasty of the ostial LM with a Flextome 4.0/6mm balloon.

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Angiography of the LM after cutting balloon angioplasty.

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Placement of an Xience Alpine 4.0/15mm stent in the LM overlapping with a previously placed stent.

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Angiography of the LM after stent placement.

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Post-dilatation of the stent in the LM with a NC Quantum Apex 4.5/8mm balloon.

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Balloon inflation of the ostium of the LCx with a NC Quantum Apex 3.0/12mm balloon.

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Distal LM bifurcation kissing balloon inflation (KBI).

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Angiography of the LM bifurcation after KBI.

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Wire removed from the LAD and LCx with follow up angiography showing abrupt vessel closure (AVC) of the mid LAD due to thrombus.

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IC vasodilators were administered through the guide catheter and failed to improve flow. This was followed by dottering of the mid LAD with a balloon.

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Angiography of the LAD after dottering showing restoration of flow.

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Balloon dilatation of the mid LAD with a Trek NC 2.5/15mm balloon. Cine acquisition shows incomplete expansion of the balloon.

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Rota Floppy wire positioned in the LAD.

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Rotational atherectomy of the LAD using a 1.5mm burr at 150k RPM.

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Angiography of the LAD after rotational atherectomy.

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Repeat rotational atherectomy of the LAD using a 1.75mm burr at 150k RPM.

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On retrieval of the 1.75mm burr, it became entrapped in the distal stent struts within the LM (red arrow). In the process of retrieving the entrapped burr, aggressive guide catheter manipulation led to longitudinal stent deformation (LSD) of the distal segment of the stent (green arrow) and proximal stent segment with an exposed dissected area (blue arrow).

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Final angiography showing unsuccessful retrieval of the burr despite use of multiple techniques (manual traction, upsizing the sheath and performing PTCA, Mother in Child catheter technique). CT surgery was called for emergent CABG and burr retrieval.

Post-procedure EKG

Case Overview

  • Underwent Impella supported intervention of the LM bifurcation.
  • A stent was placed in the LM with final KBI.
  • Wires were removed for final angiography; however, procedure was complicated by abrupt closure of the mid LAD at the location where there was haziness seen on the initial left coronary artery angiogram.
  • IC vasodilators were administered through the guide catheter and failed to improve flow.
  • LAD was wired and a balloon was used to dotter the mid LAD, restoring flow.
  • Rotational atherectomy was performed using a 1.75mm rota burr. However, when retracting the burr, it became entrapped in the distal stent struts of the recently placed stent in the LM.
  • Multiple techniques were used to retrieve the entrapped burr but all were unsuccessful (manual traction, upsizing the sheath and performing PTCA, Mother in Child catheter technique).
  • While attempting to retrieve the entrapped burr, the procedure was further complicated by LSD of the proximal stent segment due to aggressive guide catheter handling, LSD of the distal stent segment due to manual traction, and exposure of a dissected LM segment.
  • Further percutaneous attempts to retrieve the burr were abandoned and CT Surgery was consulted for surgical revascularization and burr retrieval.
  • Underwent 3-Vessel CABG with successful retrieval of the burr.
  • Patient was discharged home 8 days later without further sequelae.

Learning Objectives

  • What is the likely explanation or reason why the complication occurred?
    • Two mechanisms for burr entrapment include:
      • ‘Kokesi’ phenomenon: When performing rotablation at high RPM, frictional heat is generated and it may enlarge the space between plaque. In addition, the coefficient of friction when the burr is in motion is less than that at rest, which may facilitate the burr to pass the calcified lesion easily without debulking a significant amount of calcified tissue. Once the burr traverses the lesion, and the plaque cools the between the plaque is again reduced, and the ledge of calcium proximal to the burr prevents the withdrawal of the burr, which is known as ‘Kokesi’ phenomenon, a name given after a Japanese doll.
      • Burr can become entrapped within a severely calcified ,long and/or angulated lesion when the burr is advanced aggressively. When a large burr is pushed forcefully against this kind of lesion without an appropriate pecking motion, significant decelerations occur and this produces more debris which increases the risk for slow flow/no-reflow and burr entrapment.
    • LM stent LSD and LM dissection occurred because of aggressive guide catheter movement/handling while attempting to retrieve the entrapped burr.
    • LAD abrupt vessel closure (AVC) likely due to wire related dissection which resulted in thrombus formation.
  • How could the complication have been prevented?
    • The burr is oval shaped and coated with diamonds at its distal end, allowing for antegrade ablation. However, the proximal end is smooth and not coated with diamonds, prohibiting retrograde ablation. If a burr is advanced beyond a tight calcified lesion or embedded in a long, angulated and heavily calcified lesion, it can be entrapped. Burr entrapment can often be avoided using the following techniques/strategies:
      • Use a gentle pecking motion with shorter runs of ablation (<20s).
        • Do not exert excessive forward force during burr advancement. If the burr is advanced aggressively, it causes decelerations and can become embedded in the calcified lesion.
        • The risk for burr entrapment is greater when the lesion is long and heavily calcified, and the vessel is highly angulated.
      • When advancing the burr, avoid decelerations >5000 RPM because this results in more debris production and increases risk for slow flow/no-reflow and burr entrapment.
      • When using a smaller burr, avoid using a higher speed of rotation (>180k RPM) to prevent ‘Kokesi’ phenomenon.; optimal speed is around 150k RPM.
      • If the vessel or lesion is highly tortuous/angulated, a stiffer wire can be used to straighten the vessel or lesion to lessen the resistance and reduce wire bias.
    • Avoid performing rotational or orbital atherectomy in vessels which are highly tortuous, especially if severe wire bias is present.
    • Rotational atherectomy should be avoided after placement of a fresh stent. In this case, atherectomy using a larger burr could have been deferred, or we could have used a cutting/scoring balloon instead.
    • There was a hazy lesion present in the mid LAD for which the differential diagnosis included a calcified nodule, thrombus, hematoma or less likely SCAD. Imaging would have helped in identify the etiology of the lesion. In hindsight, this lesion in the LAD should have been treated prior to performing LM intervention.
  • Is there an alternate strategy that could have been used to manage the complication?
    • Several bailout techniques can be used to retrieve a trapped burr, but prior to proceeding forward.
      • Assure patient is adequately anticoagulated (ACT >300) before attempting percutaneous retrieval.
      • Administer intracoronary vasodilators to facilitate antegrade coronary flow and relieve possible spasm.
    • Potential strategies for retrieval of an entrapped burr include the following:
      • 1st: Manual traction of the rotablator system by pulling the burr, guidewire and/or guide catheter as a unit. This can be performed on or off Dynaglide. The vessel is at risk for perforation, dissection, and AVC. In addition, the burr shaft can fracture. If you are pulling the burr and guidewire as unit (and not the guide catheter), remember to disengage the guide catheter to prevent injury to the coronary artery from it deep seating during traction.
      • 2nd: Pass a second wire (hydrophilic-coated guidewire) beyond the trapped burr, followed by balloon dilatation around the burr. This may alter the architecture of the calcified lesion and possibly free the trapped burr. However, a 4.3 Fr rotablation drive shaft sheath may prohibit introduction of a balloon catheter into the guide catheter (consider this possibility if using a 6 or 7 Fr guide catheter). To overcome this, use a two-catheter strategy (Ping-Pong technique) where a second vascular access is obtained and equipment necessary for burr retrival is introduced through. If a single guide catheter strategy is preferred, there are two options. On approach includes cutting the rota system near the advancer, and remove the sheath to expose the driveshaft surrounding the rota-wire. This approach makes room for introduction of a second guidewire and balloon. This approach is useful when using a 6 Fr guide catheter. Alternatively, you can upsize the access sheath and guide catheter to a 8 Fr.
      • 3rd: Mother-child catheter technique can be used to wedge the burr and facilitate retrieval. The system is cut near the advancer, and the Teflon sheath is removed exposing the driveshaft which surrounds the rota-wire. A child catheter (monorail 5 Fr Guideliner or 5 Fr Guidezilla) is inserted over the exposed drive shaft and positioned as close as possible to the entrapped burr. With simultaneous traction on the burr shaft and counter-traction on the child catheter, the catheter tip wedges between the burr and the surrounding plaque, exerting a larger and direct pulling force to retrieve the burr.
      • 4th: Exclusion with a stent (As was done in this case).
      • 5th: Emergent surgical retrieval should always be the last option for removing an entrapped burr, but is often required.
    • What are the important learning points?
      • Interventional cardiologists who uses rotablation, must be familiar with complications associated with its use and their management, particularly burr entrapment which is a rare but serious complication (incidence is ~0.4%, and occurs more frequently when rotablation is used off-label).
      • Prior to retracting the burr using the various techniques above, consider disengaging the guide catheter and holding it fixed with one hand (usually the left) to prevent injury to the coronary artery from it deep seating while pulling the equipment with the opposite hand (usually the right).
Educational Content

ROTATIONAL ATHERECTOMY COMPLICATIONS

  • Common complications associated with rotational atherectomy are:1
    • Slow flow / No-reflow
    • Coronary Dissection
    • Coronary Perforation
    • Burr entrapment

Slow flow / No-reflow

  • It is most feared and preventable operator-dependent complication of Rotational Atherectomy (RA)
  • Incidence- 2.6% in the drug-eluting stent era2
  • Omens of slow-flow / no-reflow include sudden decelerations and visual, tactile or auditory clues of high resistance to burr advancement
  • Be mindful of incident chest pain, ST-segment elevations, hemodynamic instability, and bradyarrhythmia while burring which could signal no-reflow phenomenon
  • Prevention
    • Optimal antiplatelet and anticoagulant therapy
    • Continuous flush cocktail
    • Smaller burr sizes (Max burr to artery ratio 0.4-0.6)
    • Lower speeds (140-150K rpm)
    • Short ablation runs of 15-20 seconds
    • Pause between runs
  • Treatment
    • Correction of hypotension with fluids, vasopressors, and pacing as required
    • Administration of intracoronary vasodilators, such as adenosine, nitrates, nitroprusside, nicardipine, and verapamil administered distally in the vessel
    • If hemodynamically unstable, insertion of an intraaortic balloon pump to augment coronary perfusion pressure

Coronary Dissection

  • Dissections during RA are described and graded in standard fashion using the NHLBI classification system (A-F)
  • Incidence: 1.7% - 5.9% in the drug-eluting stent era 3
  • Like slow-flow / no-reflow, dissection can present with signs and symptoms of acute myocardial ischemia including chest pain, ST-segment elevations, and hemodynamic or electrical instability
  • Prevention:
    • Avoid rotablation in excessively tortuous vessels
    • Avoid excessive angulation while burring
    • Smaller burr sizes
  • Treatment:
    • Stop further ablation
    • Maintain wire position
    • Expeditious completion of PCI via balloon angioplasty and stenting if feasible

Coronary Perforation

  • Perforation represents a more severe variant of dissection in which disruption extends through the full thickness of the arterial wall.
  • Incidence: 0-2% in the drug-eluting stent era3
  • Coronary perforations during RA are described and graded in standard fashion using the Elis classification scheme (I-III)
  • Although RA is considered a risk factor for perforation,4 the majority of type III perforations result from balloon angioplasty 5
  • Risk factors: lesion-specific predictors of perforation include eccentricity, tortuosity, length >10 mm, and location in the right coronary artery or left circumflex artery
  • Prevention:
    • Correct burr sizing
    • Avoid aggressive burring
    • Avoid excessive angulation
    • Lower speeds
  • Treatment:
    • Stop further ablation
    • Maintain wire position
    • Discontinuation of anticoagulation
    • Prolonged balloon inflation (10-15 min) proximal or at site of injury. If still bleeding, repeat prolonged balloon inflation
    • If extravasation persists, seal the site with either occlusive coils [perforation site distal main vessel] or by implantation of polytetrafluoroethylene (PFTE) covered stent [perforation siteproximal main vessel, distal side branch which can be excluded with covered stent]
    • If extravasation still persists or site of injury is proximal main vessel with bifurcation (covered stent not an option) consider emergent surgery
    • Aggressive treatment with intravenous fluids, atropine, vasopressors, mechanical circulatory support if hemodynamics deteriorate

Burr Entrapment

  • Entrapment consists of burr embedding in a severe stenosis, preventing both further burr advancement and retrieval
  • Presence of diamond chips on the front, but not the rear, of the burr abets an opportunity for the burr to lodge within a lesion and become entrapped.
  • Once stuck and stalled within a lesion, retrograde ablation is not possible and friction associated with retrograde motion cannot be orthogonally displaced.
  • During ablation, the operator should be attentive to potential warning signs, which may be visual (lack of smooth advancement under fluoroscopy), auditory (pitch changes with variation in resistance encountered by burr), or tactile (resistance in advancer knob or excessive driveshaft vibration)
  • Incidence: 0.5% to 1%3
  • Prevention:
    • Meticulous relief of system tension before RA
    • Gentle pecking motions
    • Short ablation runs
    • Avoid excessive tortuosity
    • Do not stop spinning within a lesion
  • Treatment:
    • Apply forceful pull on the Rota wire with guide disengaged taking advantage of the wire’s 0.014 inches spring tip
    • Administer high dose of vasodilators and aggressively pull the Rota burr
    • Manual traction with on-Dynaglide or off-Dynaglide rotation
    • If above measures fail, potential catheter-based solutions to facilitate burr retrieval include
      • Obtain second arterial access and advance Fielder wire and a small (1~1.25mm) balloon distally, inflate at the level of Rota burr, then aggressively pull the Rota burr
      • Advance Guide extension catheters on the Rota Burr

7Fr Guide extension
Cut the Rota burr shaft at the connection outside the body, then advance 7Fr guide extension on the shaft until the Rota burr and pull aggressively.

6Fr Guide extension catheter
  • Cut the Rota burr and aggressively pull the Teflon covering sheath.
  • once done, then advance 6Fr Guide extension on the shaft until the Rota burr and pull aggressively
    • Subintimal tracking and reentry with balloon dilatation adjacent to the entrapped burr6, 7



ORBITAL ATHERECTOMY COMPLICATIONS

Differential sanding of Orbital atherectomy (OA) permits healthy tissue to flex away from the crown during orbit and can be used with speed selection options for low speed (80,000 rpm), high speed (120,000 rpm), or GlideAssist (5000 rpm).

Common complications associated with rotational atherectomy are:

  • Slow flow / No-reflow
  • Coronary Dissection
  • Coronary Perforation

Slow flow / No-reflow

Incidence: 0.9% in Orbit II trial and 0.7% in real work registry analysis.8, 9

The unique mechanism of action, differential sanding, combined with an average particle size of debris of 2.04 μm – smaller than a red blood cell – may contribute to lower rates of no-reflow and transient heart block with orbital atherectomy.10

Prevention
  • Optimal anticoagulant and antiplatelet therapy
  • Continue ViperSlide infusion
  • Always keep the crown advancing or retracting with slow advancement (1mm/sec)
  • Short run timetime ( <20 seconds)
  • Rest time = or > run time
Treatment
  • Ensure to keep the optimal blood pressure (SBP > 100Hg) and give fluids, vasopressors, and pacing as needed
  • Administer intracoronary vasodilators, such as adenosine, nitrates, nitroprusside, nicardipine, and verapamil administered distally in the vessel if necessary, via twin-pass dual access catheter
  • If hemodynamically unstable, place an intra-aortic balloon pump to augment coronary perfusion pressure

Coronary Dissection

  • Coronary artery dissection can be categorized by using NHLBI classification system (A-F)
  • Incidence: 3.4 % in Orbit II trial and 0.9% in Real world registry8, 9
  • Dissection can manifest with acute onset of chest pain, new EKG changes with ST elevations, and hemodynamic or conduction disturbances. Prevention
  • Avoid high speed run
  • Avoid in very tortuous coronary anatomy or > 2 bends exceeding 90° angulations
  • Use of ViperWire advance with flex tip in a setting of tortuous artery

  • Treatment
    • Stop ablation immediately
    • Reassess hemodynamic and patient status, then give vasopressor as needed
    • Completion of PCI with balloon angioplasty and stent placement if possible

    Coronary Artery Perforation

    • Coronary perforation is the most serious complication that can occur with OA.
    • With unique mechanism with pulsatile forces in OA, it can result in more significant tissue modification while having a higher risk of deep dissections and perforation.
    • Incidence: 0.7-2%8, 9, 11
    • Coronary perforations during OA can be graded in standard fashion using the Elis classification scheme (I-III).

    Risk factors: Very tortuosity, use of higher speed (120,000 rpm), presence of lipid rich plaque and smaller calcification arc (less than 2 quadrants in OCT/IVUS)12
    Prevention:
    • Use of lower speed (80,000 rpm)
    • Avoid excessive angulation( >2 bends exceeding 90° angulations)
    • Careful advancement when evidence of wire wrinkling from tension buildup is present leading to vessel straightening
    • Avoid high speed if the vessel diameter is less than 3 mm
    • Advance the burr slowly with a speed of 1 mm per second

    Treatment:
    • Stop further ablation immediately
    • Maintain wire position
    • Discontinuation of anticoagulation
    • Prolonged balloon inflation (10-15 min) proximal or at site of injury. If still bleeding, repeat prolonged balloon inflation
    • If extravasation persists, consider to use coils or covered stent
    • Reassess the perforation and patient status with angiogram
    • Be ready to do emergency pericardiocentesis if necessary
    • If extravasation remains present and/or site of injury is proximal main vessel with bifurcation (covered stent not an option), consider emergent surgery
    • Aggressive treatment with intravenous fluids, atropine, vasopressors, mechanical circulatory support if hemodynamics deteriorates



    References

    1. Sharma SK, Tomey MI, Teirstein PS, et al. North American Expert Review of Rotational Atherectomy. Circ Cardiovasc Interv. 2019;12(5):e007448. doi:10.1161/CIRCINTERVENTIONS.118.007448
    2. Naito R, Sakakura K, Wada H, Funayama H, Sugawara Y, Kubo N, Ako J, Momomura S. Comparison of long-term clinical outcomes between sirolimus-eluting stents and paclitaxel-eluting stents following rotational atherectomy.Int Heart J.2012; 53:149–153
    3. Tomey MI, Kini AS, Sharma SK. Current status of rotational atherectomy.JACC Cardiovasc Interv.2014; 7:345–353. doi: 10.1016/j.jcin.2013.12.196
    4. Shimony A, Joseph L, Mottillo S, Eisenberg MJ. Coronary artery perforation during percutaneous coronary intervention: a systematic review and meta-analysis. Can J Cardiol 2011;27:843–50.
    5. Al-Lamee R., Ielasi A., Latib A., et al. (2011) Incidence, predictors, management, immediate and long-term outcomes following grade III coronary perforations. J Am Coll Cardiol 4:87–95
    6. Sulimov DS, Abdel-Wahab M, Toelg R, Kassner G, Geist V, Richardt G. Stuck rotablator: the nightmare of rotational atherectomy.EuroIntervention.2013; 9:251–258. doi: 10.4244/EIJV9I2A41
    7. Tanaka Y, Saito S. Successful retrieval of a firmly stuck rotablator burr by using a modified STAR technique. Catheter Cardiovasc Interv.2016; 87:749–756. doi: 10.1002/ccd.26342
    8. Chambers JW, Feldman RL, Himmelstein SI, et al. Pivotal trial to evaluate the safety and efficacy of the orbital atherectomy system in treating de novo, severely calcified coronary lesions (ORBIT II). JACC Cardiovasc Interv. 2014;7(5):510-518. doi:10.1016/j.jcin.2014.01.158
    9. Lee MS, Shlofmitz E, Kaplan B, Alexandru D, Meraj P, Shlofmitz R. Real-World Multicenter Registry of Patients with Severe Coronary Artery Calcification Undergoing Orbital Atherectomy. J Interv Cardiol. 2016;29(4):357-362. doi:10.1111/joic.12310
    10. Sotomi Y, Shlofmitz RA, Colombo A, et al. Patient selection and procedural considerations for coronary orbital atherectomy system. Interv Cardiol 2016;11:33
    11. Parikh K., Chandra P., Choksi N., et al: Safety and feasibility of orbital atherectomy for the treatment of calcified coronary lesions: the ORBIT I trial. Catheter Cardiovasc Interv 2013; 81: pp. 1134-1139
    12. Kini AS, Vengrenyuk Y, Pena J, et al. Optical coherence tomography assessment of the mechanistic effects of rotational and orbital atherectomy in severely calcified coronary lesions. Catheter Cardiovasc Interv. 2015;86(6):1024-1032. doi:10.1002/ccd.26000


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