Sirolimus-eluting stent implantation outside a previous stent

With device improvements, more total occlusions have been crossed with a guidewire and balloon. However, true intraluminal/intrastent passage is not always accessed, which is not apparent on coronary angiography. In this study, using intravascular ultrasound as well as computed tomography, we demonstrated a crushed stent previously implanted outside the sirolimus-eluting stent, which resulted from subintimal (outside the stent) passage of a guidewire.     

Very late stent fracture associated with a sirolimus-eluting stent

Late stent thrombosis (>1 year after implantation) is a recognised complication involving drug-eluting stents. Stent fracture is increasingly being reported as a complication of drug-eluting stent, and in particular sirolimus-eluting stent use. We report the case of very late sirolimus-eluting stent fracture resulting in an acute coronary syndrome. This case report highlights the need for greater awareness and post-marketing surveillance to detect a potential mechanism for late stent thrombosis in the drug-eluting stent era.     

Embolization of a Wiktor stent within a stent: Successful nonsurgical management

A case of embolization of an unexpanded Wiktor stent while attempting to traverse an expanded Wiktor stent is reported. The embolized stent was subjected to longitudinal axial traction, using a balloon catheter to cause stretching and partial unraveling. This partially unraveled stent was deployed across the dissection to scaffold it. The patient had no postprocedure complications. © 1996 Wiley-Liss, Inc.     

Overlapping hybrid stenting with a sirolimus-eluting stent and a bare metal stent

We report a case of a 51-year-old man with transient mid-ventricular ballooning cardiomyopathy. Left ventriculography demonstrated mid-ventricular ballooning and akinesis with hypercontractile apical and basal segments. Iodine-123-beta-methyl-p-iodophenyl-penta-decanoic acid myocardial scintigraphy showed decreased uptake in the mid-ventricle, corresponding to the mid-ventricular akinetic region. This is the first report of a transient mid-ventricular ballooning cardiomyopathy observed by not only left ventriculography but myocardial scintigraphy.     

Late stent thrombosis after implantation of a sirolimus-eluting stent.

Late stent thrombosis in the era of routine high-pressure stent deployment and combined antiplatelet therapy with thienopyridines and aspirin has become a rare but feared complication. We describe a patient with acute myocardial infarction due to late stent thrombosis 6 weeks after deployment of a sirolimus-eluting stent and 2 weeks after the discontinuation of clopidogrel. This is the first report of late thrombosis of a sirolimus-eluting stent.     

Long-term biocompatibility evaluation of a novel polymer-coated stent in a porcine coronary stent model

BACKGROUND: Polymer coatings have been used to modify the surface of stents and to serve as a matrix for local drug delivery. METHODS: Bare stainless steel stents or poly-bis-trifluorethoxy phosphazene (PTFEP) dip-coated stents (Coroflex, Germany) were randomly implanted into porcine coronary arteries with a balloon-to-artery ratio of 1.1-1.2 : 1. Scanning electron microscopy (SEM), repeat quantitative coronary angiography (QCA) and histomorphometric analysis were performed at 5 days, 6 weeks and 6 months. RESULTS: At 5 days, complete endothelial cell coverage with fibrin strands was detected in both the bare and the coated stents with SEM. Late loss, determined by QCA, of coated and bare stents was identical at all time points. Histomorphometric analysis showed that coated and bare stents elicited a similar tissue response at 5 days. At 6 weeks, the coated stents showed a moderate peri-strut inflammatory response, resulting in increased neointimal hyperplasia. Compared to the bare stents, however, no significant differences were observed. At 6 months, peri-strut inflammation was minimal and similar in the coated and the bare stent groups. Neointimal hyperplasia of the coated and bare stent groups was also comparable (1.37+/-0.44 compared with 1.15+/-0.40 mm2, P=0.213) and decreased compared to the 6-week response. CONCLUSION: This PTFEP stent coating showed a long-term biocompatibility in a porcine coronary stent model. Because no increased proliferative response was observed up to 6 months, this phosphazene coating may serve as a vehicle for local drug delivery.     

When a stent gets shorty

• Stent with reduced axial force have an increased risk of longitudinal stent deformation (LSD).
• Deep guidewire catheter intubation after ostial stent deployment or attempting to push a device through an already deployed stent are frequently encountered in patients with LSD.
• Optimization of longitudinal strength along with increasing knowledge of LSD will likely reduce the frequency of this complication.

     

Dislodged and mechanically distorted stent stuck within a previously implanted drug-eluting stent

Coronary stent loss during percutaneous coronary intervention is rare and is often associated with significant morbidity. Several retrieval techniques, overlying stent deployment and crushing, and surgical removal can be used to deal with a stent lost in the coronary system. We successfully treated a dislodged and mechanically distorted coil stent stuck within a previously implanted drug-eluting stent (DES) by stent-crush technique. This case might provide insight into the mechanisms responsible for the longitudinal fragility of cobalt alloy and coil-structure stents and stent fracture of DES. In the DES era, careful attention should be paid to such complications when attempting to deliver a stent to a distal vessel through a pre-existing DES.     

Subacute stent thrombosis associated with a heparin-coated stent and heparin-induced thrombocytopenia.

Subacute stent thrombosis occurred in a patient 34 days after receiving a heparin-coated (HC) stent. The patient developed heparin-induced thrombocytopenia and diffuse thrombosis after the stent was placed. This raises the concern that patients who develop heparin-associated antibodies in the context of a recently placed HC stent may have an increased risk for subacute stent thrombosis.     

Late coronary stent infection: a unique complication after drug-eluting stent implantation

A 75-year-old male developed late coronary stent infection with symptoms presenting months after the initial procedure. This presentation was notably different than that of other cases in the literature, which typically presented days to a few weeks after stent implantation. Persistently unendothelialized stent struts may be a nidus for late infection.     

Percutaneous treatment of a coronary aneurysm by stent graft and drug-eluting stent implantation: a potential method to reduce stent graft restenosis

Coronary artery aneurysms (CAAs) can occur congenitally or secondary to specific disorders such as Kawasaki disease or atherosclerosis. Apart from a surgical approach, CAA can be treated by coronary stent graft (CSG) implantation. However, restenosis is frequent after CSG placement, precluding a wider use of this technique. We hypothesized that implantation of a drug-eluting stent (DES) within a CSG could be of use to avoid CSG restenosis. We report the case of a patient with a large aneurysm of the right coronary artery who underwent CSG implantation followed by DES placement. The immediate angiographic result showed complete exclusion of the aneurysm. Intravascular ultrasound confirmed good apposition of both the CSG and DES. Follow-up angiography after 23 weeks demonstrated a good long-term result without restenosis. The patient has remained asymptomatic during 12 months of follow-up. In conclusion, the present case suggests that CSG placement followed by DES implantation is a safe and effective approach to treat coronary aneurysms interventionally.     

Low restenosis rate of the NIR coronary stent: results of the Danish multicenter stent study (DANSTENT)--a randomized trial comparing a first-generation stent with a second-generation stent

Background Larger studies evaluating the angiographic results of second-generation stents are scarce. The objectives of this study were to assess current standards of angiographic and clinical outcomes after implantation of the second-generation stainless steel stent, NIR (Medinol Ltd, Tel Aviv, Israel), and to compare the outcomes with those of the first-generation Palmaz-Schatz (PS) stent (Johnson & Johnson, Warren, NJ). Methods Patients having coronary artery lesions that could be covered by a stent of 15 mm in length were randomly assigned to receive the NIR or the PS. Procedural success, 6-month angiographic findings, and 1-year clinical outcomes were determined. Results In 424 patients included in the study, the overall procedural success rate was high (NIR 98%, PS 99%, P = .90). Follow-up angiography was conducted in 91% of the patients. The overall rate of angiographic restenosis was low in both groups (NIR 9.9%, PS 12.6%, P = .35). We found a low restenosis rate in vessels with a minimal lumen diameter >3.1 mm after the procedure, particularly in the NIR group (<6%). The rate of target lesion revascularization after 1 year did not differ (NIR 12%, PS 10%, P = .47). Conclusions The angiographic and clinical outcomes after implantation of the second-generation stainless steel stent were not significantly better than those of the first-generation stent. The low restenosis rates, particularly in patients with the largest minimal lumen diameters after stent implantation, warrants circumspection when planning the evaluation of newer stent technologies that aim to further reduce coronary restenosis. (Am Heart J 2003;145:e5.)