Initial single-center experience with a new intracoronary stent

We investigated the safety and efficacy of the recently introduced intracoronary beStent(TM). High flexibility, zero shortening after expansion and delineating gold markers at either end of the stent are favorable features of this device. Between July 1996 and February 1997, 117 patients received a total of 126 stents, measuring 15, 25 and 35 mm in length. The majority of lesions were located in the LAD (n = 48; 38%), followed by lesions in the RCA (n = 41; 33%) and the circumflex artery (n = 28; 22%). Nine additional stents were delivered into vein grafts (7%). Successful stent deployment was achieved in 94% (n = 118), even in cases with complex lesion morphology and angulated segments. The markers proved to be helpful in placing the stent close to side-branches and whenever serial stents were used. Complications during hospitalization were as follows: one cardiac death unrelated to stenting, one subacute stent thrombosis after 30 min of effective anticoagulation and one Q-wave myocardial infarction due to peripheral thrombus embolization after stent placement in a vein graft. One patient was sent for elective CABG after an unsatisfactory procedural result. Stent loss occurred in four patients, and all stents could be retrieved successfully; in another four patients stent placement at the target site was impossible. We conclude that the investigated stent demonstrates several favorable stent characteristics which have proved to be useful in treating complex lesions by providing favorable acute results with a low complication rate.     

Immediate and long-term results of coronary stent implantation without predilatation (direct stenting) in patients with coronary heart disease

The paper assesses the immediate and long-term results of direct stenting (without the stage of predilation) and compares with the outcomes of conventional stent implantation. A prospective study included 183 patients. All the patients were divided into two groups according to the procedure of stent implantation. In 85 (46.7%) patients, the stent was implanted without preliminary predilation of stenosis (direct stenting). These patients formed Group 1. Group 2 comprised 97 (53.3%) patients in whom the stent was placed by using the routine procedure. All the patients enrolled into the study had types A, B1, and B2 stenoses according to the ACC/AHA classification and received the conventional antiaggregatory and anticoagulant therapy. The technical success of direct stenting was 97.7%. There were no cases of stent dislocation and loss during direct stenting or expansion of a balloon and stent. Analyzing the immediate results in all the patients of the both groups showed a positive angiographic success. Thus, a primary angiographic and clinical success of direct stenting was achieved in all (100%) patients. Recurrent angina pectoris with restenosis was observed in 8 (9.4%) patients in Group 1 and in 21 (21.6%) in Group 2 (p < 0.05). Direct stenting significantly differs from the routine stent implantation in all procedure parameters. Thus, direct stenting in patients with uncomplicated stenoses is a safe and feasible procedure.     

Coronary stent implantation throughout technical evolution: immediate and follow-up results

Coronary stenting (stent implantation) has evolved over the last 5 years with changes in stent design, stent material and the implantation technique. The use of high-pressure balloon inflation (HP), intravascular ultrasound (IVUS) and appropriate antiplatelet therapy have contributed to the abolishment of the need for subsequent anticoagulation, allowing extended stent applications. We compared results in three groups of patients having stent implantation throughout the period of evolution: group A: no IVUS, no HP, with subsequent anticoagulation treatment (n 3 434); group B: no IVUS, yes HP, without subsequent anticoagulation treatment (n 3 192); and group C: yes IVUS, yes HP, without subsequent anticoagulation treatment (n 3 588). The primary success rates were comparable in all groups. There was a clear change in indications for stenting in groups B and C compared with group A (elective stenting: group A 3 32%; group B 3 66%; group C 3 69%; P < 0.0001), in reference vessel size (group A 3 3.22 3 0.37 mm; group B 3 2.92 3 0.56 mm; group C 3 2.98 3 0.57 mm; P < 0.0001), and for presence of type B2 and C lesions (group A 3 57%; group B 3 72%; group C 3 74%; P < 0.001). The complication rate significantly decreased in group C (group A 3 3.6%; group B 3 4.1%; group C 3 1.2%; P < 0.001) and the mean patient hospital stay decreased to 2 days in groups B and C due to the abolition of the need for anticoagulant treatment. The angiographic restenosis rate increased in groups B and C (group A 3 20%; group B 3 34%; group C 3 32%; P < 0.001). The need for a repeat procedure increased as stenting of more complex lesions and smaller vessels was attempted: target lesion revascularization (TLR) was performed in 16% of patients in group A (73/434), in 18% of group B (35/192) and in 22% of group C (129/588) (P 3 0.04 for A versus C). Major cardiac events (MACE) occurred in 142 patients in group A (33%), 60 patients in group B (31%) and in 181 patients in group C (30%). The evolving technique of coronary stenting has expanded the spectrum of indications and range of coronary vessels attempted, and decreased the complication rates and hospital stay. However, in less-favorable subsets, additional improvements are needed to affect the long-term outcome.     

Stent implantation through a self-expanding stent

Jailing of a side-branch is a known complication of stent implantation, and makes access to the side-branch difficult, especially if the stent is of the self-expanding type. Although plain balloon angioplasty is feasible for the jailed side-branches, the use of newer devices (a stent, Rotablation or atherectomy) has not been described. We describe a novel way of treating a side-branch jailed by a self-expanding stent by using stent implantation through the strut of a self-expanding stent.     

Clinical outcomes of long coronary stents: a single-center experience

BACKGROUND: Coronary artery stenting is particularly useful during percutaneous coronary intervention for long lesions previously associated with a low procedural success rate and a high complication rate of dissection and occlusion. Current treatment options include implantation of a single long stent, multiple contiguous stents, or 'spot' stenting. However, multiple stent implantation may result in sections of overlapping stent or gaps of unstented segments and is an independent predictor of restenosis. The early and intermediate clinical outcome of single and multiple long stent (>/= 30 mm) implantation is not established. METHODS AND RESULTS: The authors retrospectively identified 123 consecutive patients who had undergone stenting using one or more long coronary stents. Baseline clinical data, procedural outcomes and completed clinical follow-up to 52 weeks were obtained by case-note review. The majority (69%) required intervention for stable coronary disease. Seventy-seven per cent of lesions were either type B2 or C and only 2% were in saphenous vein grafts. The procedural success rate was 94%. A total of 15 major events occurred in 13 patients (11%). Ten acute events occurred and five events were during the follow-up period from 30 days to 52 weeks. Two patients died, one from uncontrolled bleeding secondary to the use of antithrombotic agents and one at four weeks due to sudden death. One patient had a postprocedural infarct. Two patients required in-hospital repeat revascularization for acute vessel closure and eight required revascularization during follow-up (three cases of occlusion/thrombosis and five cases of restenosis). CONCLUSIONS: The use of long coronary stents (>/= 30 mm) for the treatment of long diffuse native vessel disease, saphenous vein graft disease and long coronary dissections is associated with a reasonable procedural success rate and acceptable early and intermediate-term clinical outcomes.     

Inadvertent intracoronary stent extraction 10 months after implantation complicating cutting balloon angioplasty for in-stent restenosis

We report the case of an unusual complication for Cutting Balloon Angioplasty (CBA) during treatment for instent restenosis (ISR), which resulted in inadvertent intracoronary stent extraction 10 months after implantation. In this case report, CBA was utilized to treat an ISR lesion in the distal right coronary artery (RCA). Due to difficulty in withdrawing the cutting balloon into the guide after treatment of the lesion, the entire system (guide, cutting balloon, and guidewire) was removed as a unit from the body. Upon examination of the system, the previously placed stent in the distal RCA was attached to the microtomes of the cutting balloon. Although the precise mechanisms for stent extraction in this case remain speculative, the initial stent used in the distal RCA may have been undersized, and this may have played a major role in this complication. Although there is limited data regarding the optimal strategy to treat the site of the inadvertent stent extraction, we opted to re-stent the area with a properly-sized coronary stent. Following the intervention, there was no residual stenosis with TIMI 3 flow through the vessel. The patient remained asymptomatic and a serum troponin drawn 18 hours after the procedure was normal, and he was discharged the next day. The interventionist must be vigilant about this rare but serious complication when applying CBA in the treatment of ISR, particularly when an undersized or underdeployed stent is suspected.     

PBSC collection in extremely low weight infants: a single-center experience

BACKGROUND: Peripheral blood progenitor cell (PBPC) collection has become the main source of hematopoietic cells for high-dose chemotherapy with stem cell rescue and, in some protocols, for allogeneic hematopoietic transplantation. This procedure is complicated in the smallest children because of difficulties related to their weight, and there is little published experience. We have conducted a prospective study to analyze the incidence of adverse events during PBPC collection in the smallest children (< or = 10 kg). METHODS: From January 2000 to November 2005, 257 leukapheresis were performed in our unit, and 13 of them (5%) in 12 children weighing up to 10 kg (median 9 kg, range 5.8-10.9 kg). RESULTS: Most cases had hypovolemic signs during the procedure (usually tachycardia); six cases had hypotension, five of them with pallor and diaphoresis, and, of those, two also had nausea. In all these cases infusion of saline or plasma volume expanders resolved the clinical findings. In two cases the nausea related to hypocalcemia was resolved after calcium gluconate infusion. Changes in platelet counts were also remarkable, with a median platelet loss of 52%. DISCUSSION: Leukapheresis with continuous-flow cell separators has frequent complications related to volume shift in the smallest children. These adverse events are mild and easily resolved with standard measures for hypovolemia, as plasma expander or normal saline infusions. However, we recommend that the procedure should only be performed by teams with extensive experience in the field.     

Stent implantation in acute myocardial infarction using a heparin-coated stent: a pilot study as a preamble to a randomized trial comparing balloon angioplasty and stenting

Preliminary experience with primary stenting in myocardial infarction has suggested a greater benefit in clinical outcome than has been obtained with direct balloon angioplasty. However, subacute thrombosis (SAT) remains a limitation for this new mode of therapy. In the BENESTENT II Pilot and main trials, the incidence of SAT with the heparin-coated Palmaz-Schatz stent was only 0.15%. Therefore, as a preamble to a large randomized trial, the feasibility and safety of the use of the Heparin-Coated Palmaz-Schatz trade mark Stent in Acute Myocardial Infarction (AMI) was tested in 101 patients enrolled between April and September 1996 in 18 clinical centres. In 101 stent-eligible AMI patients, as dictated by protocol, a heparin-coated stent was implanted. The primary objectives were to determine the in-hospital incidence of major adverse cardiac events (MACE: death, MI, target lesion revascularization) and bleeding complications, while the secondary objectives were the procedural success rate and the MACE, the restenosis and reocclusion rates at 6.5 months. Stent implantation (n 3 129 stents) was successful in 97 patients of the 101 who were included in this trial. During their hospital stay, two patients died and no patient experienced re-infarction, ischaemia prompting re-PTCA or CABG. Four patients suffered a bleeding complication, three major and one minor, of whom three required surgical repair. At 210 days follow-up, 81% of the patients were event free. At 6.5 months restenosis was documented in 18% of the 88 patients who underwent follow-up angiography, including three total occlusions. The results, both with respect to QCA and the occurrence of MACE, compare favourably with studies using elective stenting in both stable and unstable angina patients. As a result of this pilot study, a large randomized trial comparing direct balloon angioplasty with direct stenting in 900 patients with AMI was initiated in December 1996.     

Coronary stent implantation changes 3-D vessel geometry and 3-D shear stress distribution

Mechanisms of in-stent restenosis are not fully understood. Shear stress is known to play a role in plaque and thrombus formation and is sensitive to changes in regional vessel geometry. Hence, we evaluated the regional changes in 3-D geometry and shear stress induced by stent placement in coronary arteries of pigs.Methods. 3-D reconstruction was performed, applying a combined angiographic and IVUS technique (ANGUS), from seven Wallstents (diameter 3.5 (n=3) and 5mm (n=4)), which were implanted in seven coronary arteries of five pigs. This 3-D geometry was used to calculate locally the curvature, while the shear stress distribution was obtained by computational fluid dynamics. Local changes in shear stress were obtained at the entrance and exit of the stent for baseline (0. 65+/-0.22 ml/s) and hyperemic flow (2.60+/-0.86 ml/s) conditions. Results. After stent implantation, the curvature increased by 121% at the entrance and by 100% at the exit of the stent, resulting in local changes in shear stress. In general, at the entrance of the stent local maxima in shear stress were generated, while at the exit both local maxima and minima in shear stress were observed (p<0.05). Additionally, the shear stress at the entrance and exit of the stent were correlated with the local curvature (r: 0.30-0.84).Conclusion. Stent implantation changes 3-D vessel geometry in such a way that regions with decreased and increased shear stress occur close to the stent edges. These changes might be related to the asymmetric patterns of in-stent restenosis.     

Treatment of calcified ostial disease by rotational atherectomy and adjunctive cutting balloon angioplasty prior to stent implantation

Both heavily calcified and ostial lesions are difficult to deal with by percutaneous transluminal coronary angioplasty (PTCA) alone. Acute results are often sub-optimal, complications are more frequent, and long-term results are disappointing. Optimal stent deployment may not be possible unless satisfactory lesion dilatation is achieved and the lesion made more compliant. The use of rotational atherectomy and cutting balloon angioplasty to a calcified ostial lesion in the left circumflex coronary artery prior to stent implantation is reported.     

Chemotherapy in patients with progressive, undifferentiated neuroendocrine tumors: a single-center experience

Treatment of patients with undifferentiated and histologically confirmed neuroendocrine tumors (NET) usually includes chemotherapeutic intervention. This retrospective study evaluated the outcome of 2 such chemotherapies. 18 patients (11 males; age 56.2 ± 2.5) with proven progressive disease were enrolled (mean Ki-67 34 ± 5%). Patients were treated from 2005 to 2007 with regimen A (carboplatin, etoposide, paclitaxel), and from 2007 to 2009 with regimen B (cisplatin, etoposide). This change was due to low tolerability of regimen A. The standard imaging procedure was computed tomography. 8 patients underwent treatment with regimen A (mean 3.3 ± 0.7 courses). Due to severe side effects, 3 patients had their therapy prematurely discontinued. The treatment responses of 6 patients who received more than 1 course were: 0% complete response (CR), 17% partial response (PR), 50% stable disease (SD), and 33% progressive disease (PD). The median progression free survival (PFS) was 6.7 months (range 3.2-10.0). In contrast, 12 patients received regimen B (mean 3.8 ± 0.4 courses), and none of them dropped out because of side effects. The overall responses were: 0% CR, 17% PR, 42% SD, and 42% PD. The median PFS was 6.3 months (range 2.8-26.4). The response rates of both regimes were not statistically different. Patients who were treated with regimen B demonstrated comparable PFS and less severe side effects than patients who received regimen A. However, patients need to be aware of the relatively short PFS time. In order to improve therapeutic outcome of patients with progressive undifferentiated NET, new therapeutic approaches and larger multi-center studies are needed.     

Peritoneal dialysis-related peritonitis due to Staphylococcus aureus: a single-center experience over 15 years

Peritonitis caused by Staphylococcus aureus is a serious complication of peritoneal dialysis (PD), which is associated with poor outcome and high PD failure rates. We reviewed the records of 62 S. aureus peritonitis episodes that occurred between 1996 and 2010 in the dialysis unit of a single university hospital and evaluated the host and bacterial factors influencing peritonitis outcome. Peritonitis incidence was calculated for three subsequent 5-year periods and compared using a Poisson regression model. The production of biofilm, enzymes, and toxins was evaluated. Oxacillin resistance was evaluated based on minimum inhibitory concentration and presence of the mecA gene. Logistic regression was used for the analysis of demographic, clinical, and microbiological factors influencing peritonitis outcome. Resolution and death rates were compared with 117 contemporary coagulase-negative staphylococcus (CoNS) episodes. The incidence of S. aureus peritonitis declined significantly over time from 0.13 in 1996–2000 to 0.04 episodes/patient/year in 2006–2010 (p = 0.03). The oxacillin resistance rate was 11.3%. Toxin and enzyme production was expressive, except for enterotoxin D. Biofilm production was positive in 88.7% of strains. The presence of the mecA gene was associated with a higher frequency of fever and abdominal pain. The logistic regression model showed that diabetes mellitus (p = 0.009) and β-hemolysin production (p = 0.006) were independent predictors of non-resolution of infection. The probability of resolution was higher among patients aged 41 to 60 years than among those >60 years (p = 0.02). A trend to higher death rate was observed for S. aureus episodes (9.7%) compared to CoNS episodes (2.5%), (p = 0.08), whereas resolution rates were similar. Despite the decline in incidence, S. aureus peritonitis remains a serious complication of PD that is associated with a high death rate. The outcome of this infection is negatively influenced by host factors such as age and diabetes mellitus. In addition, β-hemolysin production is predictive of non-resolution of infection, suggesting a pathogenic role of this factor in PD-related S. aureus peritonitis.     

Realistic finite element-based stent design: the impact of balloon folding

At present, the deployment of an intravascular stent has become a common and widely used minimally invasive treatment for coronary heart disease. To improve these coronary revascularization procedures (e.g. reduce in-stent restenosis rates) the optimal strategy lies in the further development of stent design, material and coatings. In the context of optimizing the stent design, computational models can provide an excellent research tool. In this study, the hypothesis that the free expansion of a stent is determined by the unfolding and expansion of the balloon is examined. Different expansion modeling strategies are studied and compared for a new generation balloon-expandable coronary stent. The trifolded balloon methodology presented in this paper shows very good qualitative and quantitative agreement with both manufacturer's data and experiments. Therefore, the proposed numerical expansion strategy appears to be a very promising optimization methodology in stent design.