Optical Coherence Tomography in the Diagnosis and Treatment of Spontaneous Popliteal Artery Dissection: A Case Report

Abstract

Spontaneous dissection of the popliteal artery is an uncommon event that if left untreated can lead to severe limb dysfunction and amputation. We report a case of atraumatic, non-aneurysmal dissection of the left popliteal artery in a 76-year-old woman after a flight to Europe who presented with progressive left lower-extremity claudication and nighttime left foot resting pain. Physical exam and noninvasive arterial examination were suggestive of left popliteal artery occlusion. Treatment was undertaken before irreversible ischemia developed and the patient underwent successful percutaneous transluminal angioplasty without complications. Optical coherence tomography (OCT) was used to confirm the presence of dissection and to guide interventional therapy. We intend to illustrate the novel application of OCT imaging in peripheral interventions.

VASCULAR DISEASE MANAGEMENT 2020;17(8):E156-E160

Key words: dissection, popliteal artery, optical coherence tomography

Case Report
A 76-year-old woman with a history of hyperlipidemia and hypothyroidism developed new onset left calf claudication immediately after a 13-hour flight from Houston to Rome. The patient did not have any prior history of peripheral artery disease, hypertension, coronary artery disease, Marfan’s syndrome, fibromuscular dysplasia, ongoing smoking, atrial fibrillation, cardiomyopathy, clotting disorder, or knee trauma/surgery. Four weeks after the onset of the symptoms, she reported numbness, coolness in the left foot, and nightly left toes resting pain. Physical examination was notable for absent pulse of the left popliteal, posterior tibials, and dorsalis pedis arteries. The left lower extremity motor and sensory functions were grossly preserved and left foot coolness was apparent. An arterial Doppler ultrasound of the left lower extremity depicted monophasic flow in the distal popliteal and tibio-pedal vessels. An urgent left lower extremity magnetic resonance angiography (MRA) demonstrated segmental atherosclerotic disease with mild to moderate stenosis of the left superficial femoral artery and proximal popliteal artery, distal popliteal artery severe attenuation, and extensive collateral formation that originated proximal to the attenuated segment and ended in the infra-popliteal vessels. In the axial plane, a dissection flap was apparent (Figures 1-2).

The patient was referred for invasive angiography. The vascular anatomy on the left lower extremity was unremarkable up to the distal popliteal artery, where an apparent dissection plane was noticed with Thrombolysis in Myocardial Infarction 1 flow (TIMI-1) (Figure 3). The false lumen had compressed the true lumen with minimal antegrade flow. This initial angiography was obtained with a diagnostic 6 French (F) catheter positioned in the mid superficial femoral artery. 

A 6F 70 cm sheath was advanced to the proximal left popliteal artery via contralateral femoral access. An .014-inch Luge wire (Boston Scientific) with support of a 1.2 mm over-the-wire Mini Trek balloon (Abbott Vascular) was advanced through the dissection plane into the left anterior tibial artery. Distal injection confirmed intraluminal crossing. The balloon was removed, a SpiderFX (Medtronic) distal protection device was placed in the distal popliteal artery and optical coherence tomography (OCT) (Abbott Vascular) imaging was performed (Figure 4A-C). OCT images demonstrated an intimal tear of the left popliteal artery and very mild atherosclerotic disease. A 6 x 40 mm Chocolate balloon (Medtronic) was advanced to the site of the dissection and the lesion was dilated to 4 atmospheres (atm) for 3 minutes. Post PTA angiographic images showed TIMI-3 flow without evidence of dissection, perforation, or embolization (Figure 5). To our knowledge, there are no reported cases or series using OCT to confirm popliteal artery dissection.  

Discussion
In 2013, our group described the application of intravascular OCT in the peripheral arteries.¹ OCT provides a unique and detailed view of the vessel wall and vessel lumen. The diameter of most popliteal arteries, 4-6 mm, allows for OCT image acquisition while maintaining ultra-high resolution properties. High quality image acquisition requires complete or near-complete opacification with contrast media injected at a rate of 2-4 mL/sec. A key technical aspect with regard to image acquisition in peripheral interventions is the close proximity of the distal sheath to the site of interest, ideally within a few centimeters. This was the rationale behind the utilization of a 70 cm sheath in this case. 

Anatomically, the popliteal artery is a relatively short vascular segment subjected to movement and potent external forces, including compression, torsion, elongation, and flexion.² The patient in this case report had no known comorbidities associated with spontaneous arterial dissections. In the absence of significant focal atherosclerosis as demonstrated by OCT, one could hypothesize that focal dissection was the result of a transient increase in popliteal blood pressure due to prolonged sitting, which in turn caused elevation of the intima and a significant reduction in the diameter of the vessel true lumen, providing the mechanism for distal critical limb ischemia. Figures 4A-C illustrate the presence of a dissection flap, no significant atherosclerotic burden, and a false lumen pouch with residual thrombus. The blind sub-intimal pouch with stasis of flow leads to thrombus formation, expansion of the false lumen, and compression of the true lumen. We can’t comment on the presence of micro-fenestrations along the dissection flap, since the crossing of the dissection flap with the wire and support catheter immediately improved antegrade flow. Similar OCT images and observations have been recently described by Jackson et al in 65 patients with spontaneous coronary dissection.³  

The use of OCT to confirm wire placement in the true lumen was reassuring in that a percutaneous intervention strategy with balloon angioplasty alone could restore linear TIMI-3 flow to the foot without extending distally a sub-intimal or false-lumen plane. The safe use of scoring balloons guided by OCT images to treat spontaneous coronary artery dissection was elegantly described by Yumoto in 2014.⁴ OCT images, with their great resolution, frequently guide our selection and choice of the most appropriate interventional strategy in our peripheral cases and as in coronary cases, adds intravascular information not apparently revealed by angiography. We think that OCT has great potential in guiding best practices for vessel wall preparation in complex peripheral cases.

Our treatment preference in distal popliteal artery occlusions has been balloon angioplasty, due to the risk of stent fracture by external forces at the knee joint. Popliteal artery stenting is usually reserved for flow-compromising dissection planes that fail angioplasty-alone strategies. 

Nine months later, a follow-up arterial duplex ultrasound demonstrated the presence of normal triphasic flow in the proximal and distal popliteal artery with preservation of the lumen (Figure 6). The patient remains active and free of symptoms. 

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. They report no conflicts of interest regarding the content herein.

Address for correspondence: Dr. Oscar Rosales, email: orosales@HoustonCardiovascular.com

REFERENCES

1. Negi SI, Rosales O. The role of intravascular optical coherence tomography in peripheral percutaneous interventions. J Invasive Cardiol. 2013;25(3):E51-53.

2. Tan T-W, Armstrong FD, Zhang WW. Review of the surgical treatment of popliteal artery injury: Outcomes of open vs endovascular repair.  Vasc Dis Manag. 2016;13(8):E176-E182.

3. Jackson et al. Spontaneous coronary artery dissection: Pathophysiological insights from optical coherence tomography. JACC Cardiovasc Imaging. 2019;12(12):2475-2488.

4. Kazuhiko Yumoto, Hojo Sasaki, Hajime Aoki and Kenichi Kato. Successful treatment of spontaneous coronary artery dissection with cutting balloon angioplasty as evaluated with optical coherence tomography. JACC Cardiovasc Interv. 2014;7(7):817-819.