Download The sticky platelet syndrome during carotid endarterectomy

The sticky platelet syndrome during carotid endarterectomy
Edouard Aboian MD, Alessandra Puggioni MD, Anil P. Hingorani MD, Enrico Ascher
MD
The sticky platelet syndrome is a congenital disorder, characterized by abnormal
platelet aggregation in response to epinephrine and/or adenosine phosphate[1]
We present a case of intraoperative carotid artery thrombosis, following patch
angioplasty. The successful repair was only feasible upon administration of antiplatelet
therapy. Presence of sticky platelet syndrome should be considered during vascular
operative interventions and load of antiplatelet agents should be given in patients with
unexplained repeated thrombosis of arterial repair.
Case report
A 77 year old male presented, who to our office with asymptomatic high grade left
carotid artery stenosis. His past medical history was significant for hypercholesterolemia,
GERD, hypertension, tobacco abuse. His past surgical history was significant for right
carotid endarterectomy with patch angioplasty five months prior to presentation and
remote craniotomy. Patient was on Clopidogrel therapy following his carotid
endarterectomy, which was discontinued seven days prior to his elective left carotid
endarterectomy.
Preoperative duplex ultrasound of the left carotid artery demonstrated high grade stenosis
with peak systolic velocity 325 cm per second. His preoperative coagulation profile and
platelet count were within normal limits. His preoperative echocardiogram demonstrated
borderline left ventricular function.
He was taken for elective left carotid endarterectomy. The procedure was performed
through standard incision over medial border of sternocleidomastoid muscle. A systemic
intravenous heparin was administered prior to carotid cross clamping and ACT was
monitored throughout the entire case and was maintained above 280 seconds. An
intraoperative carotid shunt was used during the entire procedure. The carotid
endarterectomy with Dacron patch angioplasty was performed. A completion
intraoperative duplex ultrasound demonstrated the presence of mobile thrombus at the
distal extent of carotid repair. The left carotid artery was reclamped and thrombus was
evacuated through the patch arteriotomy. The thrombus had a ‘white clot appearance’
that made us suspect a reaction to heparin. All usage of heparin was stopped and
protamine was used to reverse the effect of heparin. The argatroban was administered
prior to the heparin reversal. However, on a repeat duplex ultrasound, performed upon
completion of a patch repair, the evidence of recurrent carotid thrombosis was noted. The
entire Dacron patch was removed and a carotid artery was repaired with an autologous
vein patch. A repeat carotid duplex ultrasound again demonstrated evidence of carotid
thrombosis. The patient was given a load of Abciximab and a carotid artery
thrombectomy with vein patch repair was performed. The completion duplex
demonstrated patent lumen without evidence of thrombosis. The patient then was
continued on Abciximab for 24 hours and transition to Aspirin and Plavix. A
postoperative course was notable for a mild ischemic stroke. A repeat duplex ultrasound
was performed on postoperative day six and demonstrated a patent artery without a
hemodynamically significant stenosis. At three year follow up the patient remained on
dual antiplatelet therapy and without evidence of carotid occlusion. Anticoagulation
work- up
Discussion
The sticky platelet syndrome is a congenital autosomal dominant platelet disorder
associated with an arterial and venous thromboembolism [1]. It has been characterized in
vitro by exaggerated platelet aggregation in response to low dose platelet agonists (eg,
ADP, epinephrine) and clinically by episodes of otherwise unexplained arterial or venous
occlusion. Reports of myocardial infarction or angina pectoris without identifiable
coronary artery disease[1], stroke or TIAs in younger patients and children[2], idiopathic
ischemic optic neuropathy, bilateral lower extremity ischemia have been published[3].
There are no large reported series of patients with this condition, and whether this
represents a real clinical syndrome remains uncertain. The underlying defect is not
known. Anecdotally, treatment with low-dose aspirin (eg, 81 to 100 mg/day) has been
associated with return of the platelet aggregation pattern to normal and relief from the
thrombotic symptoms. However, discontinuation of antiplatelet medications leads to
abnormal aggregation pattern[4].
We believe that this is a first report of this condition encountered during operative
intervention on carotid artery. The hyperaggregability of the platelets probably was
precipitated by discontinuation of the antiplatelet therapy prior to surgical intervention.
Besides, the stress of the operation may precipitate release of catecholamines and further
increase platelet aggregation.
In conclusion, the sticky platelet syndrome should be considered during vascular
operative interventions and load of antiplatelet agents may be given in patients with
unexplained repeated thrombosis of arterial repair
References
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361-5.
Gehoff, A., J.G. Kluge, P. Gehoff, D. Jurisch, D. Pfeifer, J. Hinz, et al., Recurrent
strokes under anticoagulation therapy: Sticky platelet syndrome combined with a
patent foramen ovale. J Cardiovasc Dis Res. 2(1): p. 68-70.
Bojalian, M.O., A.G. Akingba, J.C. Andersen, P.S. Swerdlow, P.G. Bove, O.W.
Brown, et al., Sticky platelet syndrome: an unusual presentation of arterial
ischemia. Ann Vasc Surg. 24(5): p. 691 e1-6.
Frenkel, E.P. and E.F. Mammen, Sticky platelet syndrome and thrombocythemia.
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