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Dissection Type B – Case 2

Clinical Presentation

  • 36-year-old female who presented with a NSTEMI.

Past Medical History

  • None

Clinical Variables

  • Echocardiography: Anterior wall hypokinesis, LVEF 45-50%.

Medications

  • Home Medications: None
  • Adjunct Pharmacotherapy: Clopidogrel, Bivalirudin

Pre-procedure EKG

Angiograms

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Angiographically normal right coronary artery (RCA).
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Angiographically normal right coronary artery (RCA).

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Left coronary artery angiography

  • 70-80% mid left anterior descending (LAD) coronary artery lesion.
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Diagnostic catheter (JL 3.5/5 Fr) induced, non-flow limiting Type B dissection of the LM.

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Diagnostic catheter exchanged for a guide catheter (EBU 3.5/6 Fr) with angiography showing a non-flow limiting Type B dissection of the LM.

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Deployment of a Xience Prime 3.0/33 mm stent in the mid LAD.

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Angiography of the LAD after stent placement.

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Deployment of a Xience V 4.0/18 mm stent in the LM.

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Angiography of the LM after stent placement showing successful treatment of the dissection. However, procedure further complicated by AVC of the LAD just distal to the previously placed stent in the mid LAD.

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IC vasodilators were administered using a microcatheter with no improvement in flow, raising concern for a flow-limiting Type F dissection of the mid LAD.

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Balloon dilatation of the distal stent edge using a Trek NC 2.5/20 mm balloon performed with no improvement in TIMI flow. Xience Prime 3.0/33 mm stent was deployed in the mid LAD overlapping with the distal edge of the previously placed stent in the mid LAD.

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Angiography of the mid LAD after stent placement.

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Post-dilatation of the stent placed in the LM with a Voyager NC 5.0/12 mm balloon.

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Final angiography showing successful treatment of the LM dissection and AVC with restoration of TIMI 3 flow in the LAD.

Post-procedure EKG

Case Overview

  • Underwent cardiac catheterization with procedure being complicated by diagnostic catheter induced, non-flow limiting Type B dissection of the LM.
  • PCI of the mid LAD was performed followed by direct stenting of the LM.
  • Follow up angiography after LM stent placed revealed AVC of the mid LAD, distal to the recently placed stent.
  • A microcatheter was used to deliver IC vasodilators, without improvement in coronary flow. Therefore, AVC was thought to due to a distal stent edge Type F dissection.
  • A direct stent was placed with overlap into the previously placed stent in the mid LAD.
  • This was followed by post dilatation of the LM stent.
  • Final angiogram revealed successful treatment of the LM dissection and Type F dissection with restoration of TIMI 3 flow in the LAD.
  • Troponin-I peaked at 5.5 ng/mL and CK-MB peaked at 24.4 ng/mL.
  • Patient was discharged the next day without any sequelae.

Learning Objectives

  • What is the likely explanation or reason why the complication occurred?
    • Type B dissection of the LM caused by injury from the diagnostic catheter.
    • Type F dissection involving the distal stent edge within the mid LAD is likely due to placement of a stent in a vessel which is predisposed for dissection, as the patient probably has undiagnosed SCAD.
  • How could the complication have been prevented?
    • A young female patient who presents with ACS, the possibility of SCAD should have been considered upfront.
    • Maintain guide catheter co-axiality, be cautious with manipulation of the guide catheter, and continuously monitor the position of the guide catheter throughout the procedure. This is extremely important when there is difficulty delivering equipment in tortuous, calcified, long type C lesions.
  • Is there an alternate strategy that could have been used to manage the complication?
    • PCI of the LM dissection along with medical management of residual mid LAD disease would have been a reasonable approach because the patient has likely undiagnosed Type 2 SCAD.
    • Consider using an imaging-based approach in the treatment of the dissection and AVC.
  • What are the important learning points?
    • This is a Type B dissection of the LM because of the presence of a parallel tract.
    • This is a Type F dissection of the mid LAD distal to the stent.
      • When you have AVC the differential includes spasm, thrombus with distal embolization, and dissection.
        • In this case, spasm was ruled out with administration of IC vasodilators, as no improvement in flow was seen.
        • We used bivalirudin and per institution policy, we do not engage the coronary artery with the guide catheter until ACT is >200, and do not introduce coronary equipment until the ACT is >300. Therefore, the likelihood of an intracoronary thrombus formation is low with adequate anticoagulation and antiplatelet therapy.
    • Maintaining wire position is extremely important, especially when dealing with complex interventions. Be cautious to avoid loss of wire position and possible wire entrapment.
    • Intravascular imaging of the coronaries with IVUS is helpful in the diagnosis and confirmation of SCAD, and in determining the etiology of AVC.
    • Young female patients who present with ACS, SCAD must be highly considered in the differential diagnosis. In patients with SCAD, intervention should be performed if they have electrical instability, hemodynamic instability, or ongoing ischemia, otherwise medical management is preferred.
Educational Content

ABRUPT VESSEL CLOSURE (AVC)

  • AVC is the commonest major complication of PCI8
  • Incidence: 0.3% [used to be 3% in pre-stent era]9
  • Risk factors:10
    • Proximal vessel tortuosity
    • Diffuse lesion
    • Pre-existing thrombus
    • Degenerated vein graft
    • Extremely angulated lesion
    • Unstable angina
    • Multivessel disease
    • Female gender
    • Chronic renal failure
  • Common causes:10
    • Coronary dissection
    • Intracoronary thrombus formation
    • Native thrombus (or atheroma) embolization
    • Air injection
    • Coronary no-reflow
    • Coronary vasospasm

In the current DES era, commonest causes of AVC are stent edge dissection and acute stent thrombosis. However, the cause is indeterminate in almost 50% of patients.9

  • Classification of coronary perforation: As per the National Heart, Lung and Blood Institute scheme, types A–F classification remains useful to describe the severity of luminal injury:11
Type AMinor radiolucency within the coronary lumen without dye persistence
Type BParallel tracks or double lumen separated by a radiolucent area during angiography without dye persistence
Type CExtraluminal, persisting extravasation of contrast
Type DSpiral luminal filling defects
Type EPersistent lumen defect with delayed antegrade flow
Type FFilling defect accompanied by total coronary occlusion
  • Prevention:
    • Maintain ACT > 300 throughout procedure
    • Make sure interface is free of air
    • Avoid high-pressure balloon dilatation or stenting
    • Avoid unnecessary post-dilatation and very long stents
    • Use distal protection devices in vein graft PCI
    • Be careful when retrieving delivery after stent implantation
    • Avoid geographical miss during stenting
    • Avoid aggressive post-dilatation at the stent edges
    • Be careful while positioning wire distal tip in tortuous vessel
  • Management: Abrupt closure results in acute ischemia manifesting as ECG changes, hypotension, bradycardia, chest pain and ventricular arrhythmias. The first step is to identify the underlying cause of AVC and then treat it accordingly.
    • Immediate priority should be to ensure intraluminal position of coronary guidewire and, if in doubt, an over-the-wire balloon catheter or Twin-Pass or other microcatheter should be advanced distal into the target vessel to allow minimal contrast media injection and confirm wire position.
    • If intraluminal guidewire position is confirmed, the most likely mechanism underlying AVC is dissection or intraluminal thrombus. Prompt balloon

inflation should be attempted to establish antegrade flow. If flow returns immediately after balloon inflation the likely cause of AVC is dissection and urgent stenting is useful for stabilizing.

    • If the distal flow after balloon inflation is sluggish (TIMI 0 or 1), the likely cause of AVC is distal thromboembolism. Using a Twin-Pass or microcatheter to administer distal vasodilators can help reestablish flow.
    • If initial contrast agent injection reveals guidewire position within a false lumen, careful exploration of the occluded segment using a second guidewire must be performed.
    • Aspiration thrombectomy and Glycoprotein IIb/IIIa antagonists may be helpful if acute closure is due to

thrombus. Control of anticoagulation is of paramount importance to avoid thrombotic occlusion of stented artery. ACT should be measured every ~30 minutes to keep ACT > 300 throughout the procedure and dose of anticoagulation is adjusted accordingly. If ACT is not reaching therapeutic levels consider resistance to anticoagulant and a possible reason for suspected thrombus formation causing AVC.

    • Intravenous fluids, vasopressors, inotropes and intra-aortic balloon pump (IABP) should be considered for unstable hemodynamics.
    • Emergency CABG should be considered if patient have persistent AVC depending on the location of the occlusion, patient’s clinical condition and assessment of risks and benefits.

Coronary slow flow/no-reflow phenomenon

Slow flow/No-reflow is an acute reduction in coronary flow (TIMI grade 0–1) in a patent vessel with absence of dissection, thrombus, spasm, or high-grade residual stenosis at the original target lesion.12 The underlying mechanism is complex and not completely understood, but some proposed mechanisms include distal embolization of calcium, plaque or thrombus and microvascular spasm caused by release of vasoconstrictor substances like serotonin and thromboxane, oxidative stress, and reperfusion injury.13 Clinical and lesion characteristics associated with higher incidence of no-reflow include left ventricular systolic serotonin and thromboxane, oxidative stress,and reperfusion injury.13 Clinical and lesion characteristics associated with higher incidence of no-reflow include left ventricular systolic dysfunction or hemodynamic instability, long calcified lesions, ostial lesions, chronic total occlusion of right coronary artery, thrombotic lesions, and vein graft lesions. Use of rotational atherectomy is also associated with a higher incidence of no-reflow.
Prevention
    • Direct stenting whenever feasible
    • Use of distal embolic protection devices for vein graft interventions.
    • Aspiration thrombectomy in STEMI cases if there is large thrombus burden
    • For cases involving rotational atherectomy, the use of rota flush, small

initial burr sizes, shorter rotablation runs, avoiding drops in rotations per minute (RPMs), and prevention of hypotension/bradycardia

Management: Coronary no re-flow must be immediately differentiated from AVC due to dissection as placement of stent in a vessel with no reflow may worsen the situation. Exclusion of dissection, thrombus, spasm, or high-grade residual stenosis at the original target lesion suggests no-reflow.
    • Stabilize hemodynamics with medications/intra-aortic balloon pump (IABP)
    • IC verapamil (100–200 μg)
    • IV adenosine (10–20 μg)
    • IC nitroprusside (50–200 μg)
    • Moderately forceful injection of blood or saline through the manifold
    • GPIIb/IIIa agents, IV cangrelor may also be helpful

Air Embolism

Intracoronary air embolism is a potentially lethal but rare complication. It could result in hypotension, hemodynamic collapse, cardiac arrest, and in rare cases death. Coronary air embolism is almost always iatrogenic. It occurs mostly when
    • Catheters are not adequately aspirated and flushed
    • During introduction or withdrawal of a guidewire, balloon catheter or other interventional devices
    • Do not connect the manifold to the catheter with the flush running. This may lead to an air embolism if the catheter already has a column of air inside it.
    • Draw back at least 2 cc of blood into the injection syringe and make sure that the interface is free of air prior to injection.
    • Inject some dye into the ascending aorta prior to engaging left main.
    • Always ensure that all the catheters and tubings are aspirated, flushed and free of air.
    • Take adequate care when prepping stents or balloons and ensure that the syringe tip is facing downwards.
    • Always inject with the syringe tip facing downwards
  • Do not connect the manifold to the catheter with the flush running. This may lead to an air embolism if the catheter already has a column of air inside it.
  • Draw back at least 2 cc of blood into the injection syringe and make sure that the interface is free of air prior to injection.
  • Inject some dye into the ascending aorta prior to engaging left main.
  • Always ensure that all the catheters and tubings are aspirated, flushed and free of air.
  • Take adequate care when prepping stents or balloons and ensure that the syringe tip is facing downwards.
  • Always inject with the syringe tip facing downwards

Treatment

    • Put patient on 100% oxygen.
    • Flush air free saline vigorously into the coronary arteries. Aspirate blood and air column via guide catheter and reinject saline forcefully back into coronary arteries.
    • Administer IV phenylephrine 200 μg for hypotension. Repeat, as needed every minute. If significant hypotension or hemodynamic collapse is present, push IV 1 cc epinephrine (1:10,000 dilution).
    • Intracoronary injection of vasodilators (adenosine, nitroprusside, verapamil) may be attempted.
    • Supportive measures should be instituted (IABP for persistent hypotention) and patient admitted to intensive coronary care unit for further monitoring

Coronary Vasospasm

Coronary vasospasm can be induced by PCI secondary to endothelial denudation and nitric oxide loss.
    • Some cases are catheter-induced which is caused by a contact of a catheter without balloon deployment. It is usually short-lived and is most prone to occur at the ostium of the right coronary artery (RCA). The left main is less susceptible to ostial spasm
    • Rotablator cases are more prone to vasospasm
Diagnosis
    • Coronary vasospasm is detected by presence of EKG changes of ST segment elevation in association with angina, and then EKG completely returns to baseline upon resolution of symptoms.
    • The definitive diagnosis of coronary vasospasm is made angiographically by demonstration of reduction of luminal diameter in a discrete segment of the vessel, which is proven reversible by the administration of intracoronary vasodilators.
Treatment
    • Initial step is intracoronary vasodilatation with IC calcium channel blockers and/or nitrates [nitroglycerin 100-300 mcg, verapamil 100 mcg/min, up to 1.0-1.5 mg, nicardipine 100-300 mcg, nitroprusside 100-300 mcg]
    • IV atropine can be useful if there is associated hypotension of bradycardia
    • If vasospasm persists, remove all hardware and leave the guide wire in place to maintain position. This may

If vasospasm persists, remove all hardware and leave the guide wire in place to maintain position. This may minimize distal vessel spasm

    • Repeat prolonged PTCA for 2-5 minutes at low pressures (1-4 atmospheres)
    • Stenting should be reserved in cases if all the above measures have failed, as it may lead to propagation of spasm to a new location
    • Refractory vasospasm may be indicative of dissection, which is also an indication for stenting


Abrupt Vessel Closure Summary

  • Dissection
    • Minor dissections - usually heal without clinical sequelae, no treatment required
    • Major dissections - repeated prolonged low-pressure balloon [distal vessel], stenting [Proximal/mid vessel segment or impaired flow due to dissection]
  • Thromboembolism
    • Twin-Pass or microcatheter to administer vasodilators distally
    • Check ACT to keep > 300. Consider starting IV Cangrelor or bailout GPIs
    • Balloon dilatation and/or thrombus aspiration in case of stent thrombosis
    • Stenting on case of thrombosis in in unstented vessel segment
  • No-reflow
    • Intracoronary Adenosine, Nitroprusside, Nicardipine, Verapamil, or GPI’s
    • A transit catheter or over-the-wire balloon should be used to deliver the vasodilators to the distal microvasculature
    • Insertion of IABP to improve flow
  • Air embolism
    • Start 100% oxygen
    • Flush air free saline vigorously into the coronary arteries. Aspirate blood via guide catheter and reinject forcefully back into coronaries
    • IV phenyl epinephrine or epinephrine as needed
    • Intracoronary injection of vasodilators
  • Vasospasm
    • Intracoronary Nitroglycerin, Adenosine, Nitroprusside, Nicardipine, or Verapamil
    • IV fluid bolus and/or atropine as needed
    • Remove all hardware and leave the guide wire in place to maintain position
    • Repeat prolonged PTCA for 2-5 minutes at low pressures (1-4 atmospheres)
  • Unknown etiology
    • Maintain wire position distally and pass a microcatheter distally to inject contrast
    • If flow distally, problem at site of vessel closure and needs to be investigated
    • If no flow distally, consider no reflow and give IC vasodilators


References

  1. de Feyter P.J., de Jaegere P.P.T., Murphy E.S., Serruys P.W. (1992) Abrupt coronary artery occlusion during percutaneous transluminal coronary angioplasty. Am Heart J 123:1633–1642.
  2. Francesco Giannini, Luciano Candilio, Satoru Mitomo, Neil Ruparelia, Alaide Chieffo, Luca Baldetti, Francesco Ponticelli, Azeem Latib, Antonio Colombo. Practical Approach to the Management of Complications During Percutaneous Coronary Intervention. J Am Coll Cardiol Intv. 2018 Sep, 11 (18) 1797-1810.
  3. Klein L. (2005) Coronary complications of percutaneous coronary interventions: a practical approach to the management of abrupt closure. Catheter Cardiovasc Interv 64:395–401.
  1. Huber MS, Mooney LF, Madison J, et al. Use of a morphologic classification to predict clinical outcome after dissection from coronary angioplasty. Am J Cardiol 1991;68:467–71.
  2. Rezkalla S.H., Kloner R.A. (2002) No-reflow phenomenon. Circulation 105:656–662.
  3. Piana R., Paik G., Moscucci M., et al. (1994) Incidence and treatment of “no-reflow” after percutaneous coronary intervention. Circulation 89:2514–8.