The Best Strategy for the Black Hole Phenomenon between Intravascular Ultrasound and Optical Coherence Tomography

The black hole (BH) phenomenon is an intraluminal restenotic lesion. It was identified by intravascular ultrasound (IVUS) and optical coherence tomography (OCT) after intracoronary brachytherapy and drug-eluting stent implantation. Despite the similarity in the mode of action of brachytherapy and drug-eluting stent implantation, the BH phenomenon appears to be uncommon after drug-eluting stent implantation. Specifically, the BH phenomenon is better identified by OCT than by IVUS. Herein, we present a case of in-stent restenosis with suspected BH phenomenon on IVUS and confirmed by OCT.

Pathological assessment of very late bare metal stent thrombosis in the left main coronary artery: a case report

Background

Late catch-up phenomenon following stent implantation is a well-known complication. However, no report has evaluated thrombosis after 9 years with multi-modality and pathological evaluation.

Case summary

A 71-year-old man with stable angina underwent elective percutaneous intervention of the left main coronary artery with implantation of a bare metal stent (BMS) 9 years ago. At the 9-year follow-up, coronary computed tomography (CCT) and coronary angiography (CAG) findings revealed a thrombus-like structure in the BMS slightly protruding into the sinus of Valsalva. Therefore, the previously prescribed double-antiplatelet therapy was replaced with an anticoagulant and clopidogrel, and a potent statin treatment was initiated. After the changes in drug treatment, follow-up examinations with CCT at 1 and 3 months suggested a decrease in the size of the thrombus; however, it appeared to increase after 6 months. Subsequently, the patient underwent surgical intervention. Pathological assessment of the explanted stent showed a proteoglycan-dominated extracellular matrix with few smooth muscle cells suggesting an organized thrombus.

Discussion

It should be emphasized that multiple factors might be responsible for very late stent thrombosis, such as peri-stent strut chronic inflammation involving proteoglycans, stent protrusion, and poorly controlled type 2 diabetes mellitus, possibly further inducing inflammatory cells.

Black hole restenosis after drug-eluting stent implantation for in-stent restenosis: potential mechanism and optimal strategy

In-stent restenosis (ISR) has long remained as the major limitation of coronary stenting. The use of drug-eluting stent (DES) reduces the risk of repeat revascularization without an increase of death and myocardial infarction, compared to the standard bare metal stents. DES has also demonstrated markedly to reduce ISR for complex lesions. However, ISR after DES implantation still occurs and optimal treatment for ISR after DES has not been established. Herein, we report 3 cases with black hole restenosis confirmed by intravascular ultrasound at the site of overlapped DES and discuss potential mechanism and optimal strategy for this phenomenon.

Impact of statin therapy on late target lesion revascularization after sirolimus-eluting stent implantation (from the CREDO-Kyoto Registry Cohort-2)

Therapeutic strategies preventing late target lesion revascularization (TLR) after drug-eluting stent implantation have not been yet adequately investigated. In 13,087 consecutive patients undergoing first percutaneous coronary intervention in the CREDO-Kyoto Registry Cohort-2, we identified 10,221 patients who were discharged alive after implantation of sirolimus-eluting stents (SESs) only (SES stratum 5,029) or bare-metal stents (BMSs) only (BMS stratum 5,192). Impact of statin therapy at time of discharge from the index hospitalization on early (within the first year) and late (1 year to 4 years) TLR, was assessed in the SES stratum (statin group 2,735; nonstatin group 2,294) and in the BMS stratum (statin group 2,576; nonstatin group 2,616). Despite a significantly lower incidence of early TLR (7.8% vs 22.2%, p <0.0001), SES use compared to BMS use was associated with a significantly higher incidence of late TLR (7.7% vs 3.0%, p <0.0001). In the SES and BMS strata, the incidence of early TLR was similar regardless of statin use. In the SES stratum, the incidence of late TLR was significantly lower in the statin group than in the nonstatin group (6.1% vs 9.6%, p = 0.002), whereas no significant difference was found in the BMS stratum (2.6% vs 3.3%, p = 0.38). After adjusting confounders, risk for late TLR significantly favored statin use in the SES stratum (hazard ratio 0.73, 95% confidence interval 0.54 to 0.98, p = 0.04), whereas the risk decrease was not significant in the BMS stratum (hazard ratio 0.74, 95% confidence interval 0.46 to 1.20, p = 0.23). In conclusion, statin therapy at hospital discharge was associated with a significantly lower risk for late TLR after SES implantation.

Very Long-Term (15 to 20 Years) Clinical and Angiographic Outcome After Coronary Bare Metal Stent Implantation

Background—

We previously reported that the long-term luminal response after coronary bare metal stenting is triphasic, with an early restenosis phase spanning the 6 months after the index procedure, an intermediate-term regression phase from 6 months to 3 years, and a late renarrowing phase beyond 4 years. However, the clinical significance of late luminal renarrowing remains unknown.

Methods and Results—

Angiographic and clinical follow-up of the same cohort of 405 patients with successful Palmaz-Schatz stent placement was extended beyond 15 years. Clinical follow-up was completed in 98% of patients at 5 years and in 81% at 15 years. The incidence of death and cardiac death at 15 years was 45.4% and 20.6%, respectively. Paired long-term (4 to 10 years) and very long-term (>10 years) angiographic studies without intercurrent target lesion revascularization were performed in 55 lesions, and minimal luminal diameter further decreased from 1.88±0.50 mm to 1.60±0.73 mm ( P =0.002). Late target lesion revascularization after initial stabilization of the stented segments occurred rarely within 4 years. Beyond 4 years, however, the incidence of late target lesion revascularization increased steadily from 3.3% at 4 years to 24.7% at 15 years. The incidence of definite very late stent thrombosis was low (1.5% at 15 years).

Conclusions—

Luminal renarrowing of the stented segment beyond 4 years was a progressive process extending beyond 10 years. The angiographic observation of late in-stent restenosis was clinically relevant because a corresponding progressive increase in the incidence of late target lesion revascularization was observed beyond 4 years and up to 15 to 20 years after bare metal stent implantation.