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Clinical Images
Black Hole Phenomenon Observed on IVUS after Late Restenosis following Sirolimus-Eluting Stent Implantation
August 2009
Case Description. A 75-year-old male with a previous history of coronary artery disease was admitted with stable angina. He had undergone percutaneous coronary intervention to the proximal left anterior descending (LAD) coronary artery 43 months previously when a drug-eluting stent (DES) was implanted (Cypher 3.5–28 mm, Cordis Corp., Miami, Florida). Coronary angiography showed focal in-stent restenosis (ISR) (Figure 1). The appearance of the ISR on intravascular ultrasound (IVUS) (Atlantis SR, 40 MHz, Boston Scientific Corp., Natick, Massachusetts) showed echolucent neointimal tissue called “black holes” by some investigators, whereas the distal edge shows an echoreflective appearance (Figure 2). The appearance on computed tomography (CT) also shows a very low-density appearance at the ISR site as compared to distal edge ISR (Figure 3). The low-density appearance is consistent with the echolucent appearance on the IVUS images. This patient was treated by cutting balloon angioplasty (Cutting Balloon 3.5–10 mm, Boston Scientific) with a good result.
Discussion. ISR is the result of neointimal hyperplasia that, by IVUS imaging, typically has a homogenous, echoreflective appearance. Histological analysis has typically shown spindle-shaped mesenchymal cells with very little elastin and collagen1,2 in patients with ISR. There have been some reports of IVUS appearance of echolucent neointimal tissue called “black holes,” which is mainly reported after the application of brachytherapy and in the saphenous vein graft restenotic lesions. Atherectomy specimens in such lesions have shown acellular and necrotic tissue lacking connective tissue elements, scattered in an extracellular matrix containing proteoglycan.3 Ribmar Costa et al4 have shown that the incidence of black holes by IVUS is more commonly seen following sirolimus-eluting stent (SES) restenosis in the saphenous vein graft lesions or following treatment of bare-metal stent restenosis. They have also reported that SES restenosis appears earlier and is more severe and aggressive in patients with IVUS appearance of black holes in restenotic tissue.4 A similar phenomenon was also reported by Suzuki et al in a histological study.5 The “black hole” phenomenon is seen rarely and may have a potential impact on the subsequent risk of thrombosis or the rate and severity of restenosis.
In conclusion, IVUS appearance of the black hole phenomenon is sometimes seen in patients treated with brachytherapy and in saphenous vein graft restenotic lesions. This phenomenon is rarely reported in patients with drug-eluting stent restenosis, and in these cases, its appearance seems to be early and is more aggressive. To our knowledge, this is the first case reported late after drug-eluting stent implantation for a de-novo lesion showing black holes by IVUS imaging.
From the Department of Cardiology, Toyohashi Heart Center, Toyohashi, Japan.
The authors report no conflicts of interest regarding the content herein.
Manuscript submitted January 12, 2009, provisional acceptance given January 22, 2009, final version accepted February 10, 2009.
Address for correspondence: Sudhir Rathore, MD, MRCP (UK), Department of Cardiology, Toyohashi Heart Center, 21-1, Gobudori, Oyama-cho, Toyohashi, Japan 441-8530. E-mail: sudhirrathore@hotmail.com
1. Komatsu R, Ueda M, Naruko T, et al. Neointimal tissue response at sites of coronary stenting in humans: Macroscopic, histological, and immunohistochemical analyses. Circulation 1998;98:224–233.
2. Farb A, Sangiorgi G, Carter AJ, et al. Pathology of acute and chronic coronary stenting in humans. Circulation 1999;99:44–52.
3. Hehrlein C, Kaiser S, Riessen R, et al. External beam radiation after stent implantation increases neointimal hyperplasia by augmenting smooth muscle cell proliferation and extracellular matrix accumulation. J Am Coll Cardiol 1999;34:561–566.
4. Ribmar Costa JD, Mintz GS, Carlier SG, et al. Frequency and determinants of “black holes” in sirolimus-eluting stent restenosis. J Invasive Cardiol 2006;18:348–352.
5. Suzuki N, Angiolillo DJ, Monteiro C, et al. Variable histological and ultrasonic characteristics of restenosis after drug-eluting stents. Int J Cardiol 2008;130:444–448.
