Angiographic and clinical outcome following paclitaxel-eluting stent (taxus) implantation: a single center experience

Highly selective and sensitive assay for paclitaxel accumulation by tumor cells based on selective solid phase extraction and micro-flow liquid chromatography coupled to mass spectrometry

The taxanes are among the most important cancer chemotherapy drugs approved for clinical use in the last two decades. Paclitaxel is used as first-line therapy for a variety of cancers, and numerous drug delivery approaches are under investigation to enhance its selectivity and effectiveness against tumors. One strategy is to produce sustained, low drug levels within the tumor to enhance apoptosis and inhibit angiogenesis. The interest in altering drug concentration/time exposure profiles to improve therapeutic outcomes creates the necessity to quantify low concentrations of paclitaxel in cells or tissues. Here, a selective solid phase extraction (SPE) method, coupled with a capillary liquid chromatography-tandem mass spectrometry (microLC-MS/MS) method, was developed to quantify low, therapeutically relevant concentrations of paclitaxel that could not be analyzed using conventional LC-MS/MS. Under optimized SPE wash and elution conditions, paclitaxel was selectively extracted from biological samples, and most matrix components were removed. A 150 x 0.5 mm ID ODS capillary column was used for microLC separation and the flow rate was 12 microL min(-1). Sample extracts were focused at the front of the microLC column and then eluted with a gradient. The lower limits of detection and quantification were 5 and 20 pg mL(-1), respectively, permitting quantification of paclitaxel in small tissue samples or in cultured cells exposed to low drug concentrations. The quantitative linear range was 20-20 000 pg mL(-1). The ability to quantify these low concentrations of paclitaxel provides an important tool to study the concentration-dependent pharmacological effects of this important drug.

Angiographic and clinical outcome following sirolimus-eluting stent (Cypher) implantation. A single center experience

OBJECTIVES

To investigate the late outcomes of sirolimus-eluting stent implantation in patients with coronary artery disease.

BACKGROUND

Drug-eluting stents reduce intimal hyperplasia, which is the main cause of in-stent restenosis. Sirolimus-eluting stents significantly reduce clinical and angiographic restenosis and improve event-free survival.

METHODS

The study population consisted of 207 patients (273 stents) who had undergone coronary Cypher stent implantation. Patients were eligible for enrollment if there was symptomatic coronary artery disease or positive exercise testing, and angiographic evidence of single or multivessel disease with a target lesion stenosis of > or = 70% in a > or = 2.25 mm vessel. Follow-up coronary angiography was performed 18 months after stent deployment. Patients were followed-up for a mean of 24.7 +/- 7.4 months.

RESULTS

All patients survived after stent implantation, but 5 (2.4%) patients experienced acute ST elevation myocardial infarction and 4 (1.9%) patients developed non-Q wave myocardial infarction following angioplasty. Recurrent angina pectoris was observed in 16 (7.7%) patients (11 stable angina pectoris and 5 unstable angina pectoris). Angiographic evidence of restenosis was observed in these 20 (9.66%) patients. The 5 other patients had noncritical angiographic restenosis. Eleven (5.3%) patients underwent angioplasty because of restenosis, and coronary artery bypass grafting was conducted in the other 9 (4.3%) patients.

CONCLUSION

The results of the present study indicate that Cypher stents could be implanted with a very high success rate and have encouraging long-term angiographic and clinical results.

Initial and Long-Term Outcomes of Sirolimus-Eluting Stents for Calcified Lesions Compared With Bare-Metal Stents

The aim of this study was to compare the initial and long-term outcomes of sirolimus-eluting stents (SES) and bare-metal stents (BMS) in patients with calcified lesions without performing rotational atherectomy. The subjects were 79 consecutive lesions (38 in the SES group and 41 in the BMS group) which were confirmed to have superficially calcified lesions by intravascular ultrasound. In all lesions, the stent was implanted after predilatation with a balloon. The patient characteristics were not different between the 2 groups. All procedures were successfully performed in both groups. Vessel area was significantly smaller in the SES group than in the BMS group (11.01 +/- 3.88 mm(2) versus 13.08 +/- 3.49 mm(2), P < 0.005), as was the lumen area (5.41 +/- 2.31mm(2) versus 6.48 +/- 2.04 mm(2), P < 0.005). Minimum stent area was significantly smaller in the SES group than in the BMS group (5.61 +/- 1.54 mm(2) versus 6.69 +/- 1.74 mm(2), P < 0.01). In cases in whom angiographic follow-ups were performed, the late loss was significantly smaller in the SES group than in the BMS group (0.19 +/- 0.49 mm versus 0.76 +/- 0.48 mm, P < 0.001). The restenosis rate was significantly lower in the SES group than in the BMS group (8.8% versus 33.3%, P < 0.05) and the TLR rate tended to be lower in the SES group (7.9% versus 19.5%). Stent thrombosis was not observed in either group. The results suggest that SES are more effective than BMS and can be used safely when treating calcified lesions if predilatation with a balloon is possible.

Effectiveness of a Sirolimus-Eluting Stent (Cypher ) for Diffuse In-Stent Restenosis Inside a Bare Metal Stent

We estimated the benefit of a sirolimus-eluting stent (SES, Cypher) for diffuse (> 10 mm) in-stent restenosis (ISR) inside bare metal stents (BMS) because the feasibility of the SES was not confirmed after its recent approval in Japan. Clinical and angiographic outcomes after SES implantation to 93 diffuse ISR were compared with those of 3 groups treated by plain old balloon angioplasty (POBA, (n = 54)), cutting balloon angioplasty (CB, (n = 24)), and BMS (n = 41) in a series of 153 patients whose follow-up quantitative coronary angiography (QCA) evaluated 3-9 months after the treatments was obtained from January 2003 through December 2005. For 33 lesions in the SES group, 12-month follow-up QCA results were obtained and compared with those at 6 months. Ticlopidine (200 mg/day) was prescribed for at least 12 weeks after SES implantation and for 2 weeks after BMS in addition to aspirin (81-100 mg/day). Patient characteristics and the characteristics of previous implanted BMS in the SES group were not significantly different from those in the other groups. Death from cardiac causes and nonfatal myocardial infarction did not occur in any group. Stent thrombosis was not observed in the BMS and SES groups. The incidence of repeat target lesion revascularization (re-TLR) in the SES group (3.23%) was significantly lower compared with that of the POBA (37.0%), CB (25.0%), and BMS (29.3%) groups (P < 0.001, respectively). Late loss in the SES group (0.44 +/- 0.41 mm) was significantly smaller than that in the BMS group (1.34 +/- 0.74 mm) (P < 0.05). The rate of recurrent ISR (re-ISR) in SES (5.38%) was significantly lower than that in POBA (46.3%), CB (41.7%), and BMS (46.3%) (P < 0.001, respectively). The QCA variables at 6 months in the SES group were not significantly different from those at 12 months. Thus, SES implantation for diffuse ISR was far superior since it markedly reduced the incidence of re-TLR with re-ISR at up to 6-months follow-up. In addition, this angiographic patency after SES implantation continued until 12 months.