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Case 16: Stent malapposition and underexpansion in RCA

Case 16: Stent malapposition and underexpansion in RCA

Case Presentation

A 54-year-old male had been admitted to our hospital with exertional chest pain and a history of prior MI, hypertension, hyperlipidemia, and multiple PCI procedures. Echocardiography showed reduced left ventricular wall motion in the posterior and infer walls, with Ejection Fraction of 45%. Coronary angiography revealed 70% stenosis at the proximal RCA (in-stent restenosis, previous stent was 4.0mm DES).

Angio Pre

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IVUS Pre

IVUS pullback showed an underexpanded stent in the proximal site due to calcified plaque. In angiography, only a stenosis was identified in the part of the proximal stented segment, but IVUS also showed stent malapposition in the distal and proximal edges of the stent. In the proximal site, the lumen diameter was 5.0mm while the stent diameter was 3.6mm. The MLA was 4.26mm². Therefore, we placed a 5.0mm non-compliant (NC) balloon at the site where malapposition was observed and dilated up to 24 atm. Finally, we confirmed that the stent had been well-expanded at all sites by IVUS. Post MLA was 18mm².

Angio Post High-pressure PTCA

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IVUS Post

In this case, IVUS revealed inadequate stent expansion in the site that appeared to be fine on angiography. IVUS often provides information that is not available or less clear on angiography alone.

Whether stent malapposition is harmful or harmless is still debatable, but the presence of stent malapposition in the proximal edge of the stent could allow a guidewire to pass through the stent strut during future PCI leading to serious deformation by guidewires, balloons, catheters, etc.