Cardiovascular radiation medicine最新文献

Background

Vascular (VBT) has clearly been shown in multiple clinical trials to decrease restenosis rates for in-stent restenosis (ISR). However, patients enrolled in these randomized clinical trials represent a select group, and the efficacy of VBT in patients with ISR who were excluded from these controlled trials due to more complex coronary anatomy requires further investigation. This study sought to define the angiographic and clinical profile and outcomes of these high-risk patients with ISR who were excluded from the randomized clinical trials and who received VBTusing Strontium-90 (Sr-90) using the Novoste Beta-Cathk System through a Compassionate Use Protocol (CUP).

Methods

The study was designed as a single center, prospective, open label registry trial evaluating the use of VBT on complex instent restenotic lesions in patients who were excluded from the START and START 40 trials. In general, these patients included those with saphenous vein graft (SVG) lesions, long lesions (>35 mm), and patients with a history of more than three prior interventions. VBT using Sr-90 was delivered using the Novoste Beta-Cathk System after successful angioplasty. The predetermined primary endpoint was freedom from target vessel revascularization (TVR) at 8 months, one and two years. The secondary endpoint was a composite of death, myocardial infarction (MI) and TVR at 8 months, one year, and two years.

Results

Between September 4, 1998 and December 6, 2000, 32 patients were treated with VBT under the UCP protocol. The mean duration of follow up was 15.3F8.3 months. There were 9 major cardiac events at eight months including one death, one acute myocardial infarction and 7 TVR. Excluding the one patient who died, 33 lesions were available for follow-up. The rate of TVR in this high-risk patient population was 21.1% (n = 7/33 lesions). The method of revascularization included one bypass surgery and 6 repeat percutaneous coronary interventions.

Conclusions

This trial demonstrates that utilization of the Beta-Cathk System using Sr-90 for the treatment of ISR in a patient population excluded from the randomized clinical trials due to unfavorable lesions characteristics is feasible appears to be associated TVR rates that compare favorably with the event rates of patients enrolled in other trials enrolling lower-risk groups.

Purpose

Secondary malignant tumours and cardiovascular complications are of great importance among the late complications after treatment for Hodgkin's disease (HD) because they may significantly reduce the patients' life expectancy. We report on coronary artery disease (CAD) after treatment for HD.

Methods and Materials

We present the case of two female patients with HD who received mediastinal irradiation after which complete remission was achieved. In 12 and 19 years after the onset of the disease, control examinations revealed ischaemic heart disease, which was confirmed by coronary arteriography and solved by stent implantation in one of the patients and bypass surgery in the other one.

Conclusions

Ischaemic heart disease was due to early CAD, which was associated with mediastinal irradiation accompanied by hypothyroidism, hyperlipidaemia and, possibly, early menopause, all posing an increased risk for the cardiologic disease. Our cases may serve as a warning example to carefully plan the management (low dose, involved field irradiation) of newly diagnosed patients as well as the cardiologic follow-up of patients with HD.

Cellular proliferation and migration are fundamental processes that contribute to the injury response in major blood vessels. The resultant pathologies are atherosclerosis and restenosis. As we begin to understand the cellular changes associated with vascular injury, it is critical to determine whether the inhibition of growth and movement of cells in the vasculature could serve as a novel therapeutic strategy to prevent atherosclerosis and restenosis.

Drug-eluting stents (DES) have significantly reduced the incidence of restenosis. Although the results obtained with these novel antiproliferative devices are encouraging, recent reports have shown that DES are not completely immune from restenosis. Therefore, the broad use of DES has inevitably led to a major issue: treatment of DES failure. Intracoronary brachytherapy (IBT) represents an important advancement for treatment of in-stent restenosis (ISR) and has led to important pathophysiological insight on the restenotic process. To date, IBT, when properly used, still represents the gold standard for treatment of ISR. However, experience with IBT is for treatment of ISR occurring with bare metal stents (BMS). Whether IBT may be used with the same safety and efficacy profile as an adjunctive treatment for ISR following DES implantation is still unknown. In this article, we report the outcome of a series of patients with DES failure treated with IBT. IBT for treatment of DES failure was shown to be both safe and efficient and, therefore, until ISR exists, IBT still remains an important player in this growing and even more challenging setting.

Background

Subacute stent thrombosis (SAT) is a dramatic complication of percutaneous coronary stenting occurring in 0.4–20% of cases depending on several angiographic and clinical variables. The role of postprocedural low molecular weight heparin (LMWH) in preventing early events after high-risk PCI is not well established. In this study we describe our experience with postprocedural LMWH in patients deemed to be at high risk of SAT.

Methods

Thirty-six patients who were treated with subcutaneous LMWH for at least 7 days after the intervention were identified from our database. All cineangiograms and charts were retrospectively reviewed to confirm the high-risk intervention properties. Thirty-day and long-term major adverse coronary events (MACEs) were documented in all patients.

Results

The most common indications for LMWH were the deployment of ≥3 consecutive stents, the presence of intracoronary thrombus or ulceration, poststenting residual stenosis, contraindication to aspirin or thienopyrideines, and persistent dissection. The majority of patients (61%) had ≥2 risk factors. Mean postprocedural treatment period was 12±3 days. At 30 days, none of the patients experienced a MACE including death, myocardial infarction, and repeat revascularization. No major bleeding occurred and one patient (2.7%) had a minor bleeding. At a mean follow-up of 31 months, MACE occurred in 17% of patients.

Conclusions

Postprocedural LMWH is safe and effective in preventing SAT in patients undergoing high-risk coronary intervention.

Background

Optical coherence tomography (OCT) is a light-based imaging modality that can be used in biological systems to study tissues in vivo with near-histologic, ultrahigh resolution. The rationale for intravascular application of OCT is its potential for in vivo visualisation of the coronary artery microstructure.

Methods and results

The principle is analogous to pulse-echo ultrasound imaging; however, light is used rather than sound to create the image. Low-coherent near-infrared light is emitted by a superluminescent diode and reflected by the microstructures within biological tissues. The echo time delay of reflected light waves is converted into a two-dimensional spatial image. The intensity of the reflected light waves is translated into an intensity map. Experimental studies confirmed the ability of intravascular OCT for plaque characterisation and accurate assessment of vascular structures that are close to the luminal surface. Preliminary clinical experience proved in vivo feasibility of intravascular OCT. A variety of atherosclerotic plaque structures including thin cap fibroatheromas can be visualized in vivo.

Conclusions

Intravascular OCT allows for accurate assessment of vessel structures close to the luminal side. Clinical application is feasible. To date, however, the clinical relevance of OCT findings in coronary arteries is unclear and further validation of OCT imaging is mandatory.

Background

Vascular injury results in specific temporal patterns of increased matrix metalloproteinase (MMP) activity. MMPs are known to play a role in remodeling and neointimal (NI) thickening. Although in vitro data on the role of metalloproteinases and their inhibitors on smooth muscle cell migration and proliferation are compelling, evidence for inhibition of NI thickening in vivo is inconsistent and is mostly generated in models of balloon angioplasty instead of the more prevalent stent placement. Data from atherosclerotic models are scarce. The objective of the study was to investigate whether the nonspecific MMP inhibitor batimastat, in concentrations known to influence remodeling, could also inhibit NI thickening following stent placement in an atherosclerotic model.

Methods

Stents were placed in atherosclerotic femoral arteries in Yucatan micropigs on a high cholesterol diet and followed for 6 weeks. Batimastat or vehicle was administered intraperitoneally. NI thickening was assessed by morphometry.

Results

The main finding was that batimastat did not result in a significant decrease in NI thickness. Only following correlation to the amount of preexisting plaque was the difference of 146 μm (19%) statistically significant. Batimastat did not impair wound healing following stenting.

Conclusion

Batimastat does not significantly influence the degree of NI thickening at 6 weeks following stenting of atherosclerotic porcine femoral arteries, except when correlated to plaque thickness. Batimastat does not affect vascular wound healing.

Introduction

Vascular brachytherapy reduces recurrence after treatment of in-stent restenosis. However, there are still failures. The aims of the study were to investigate the relationship between two distinct dose prescriptions and the calculated dose delivered versus binary angiographic restenosis.

Methods and Materials

Fifty-five lesions in 47 patients underwent catheter-based β-brachytherapy with a ³²P source. Doses delivered were calculated using intravascular ultrasound (IVUS) measurements. Patients randomly received 20 Gy either at 1 mm beyond mean reference lumen or 1 mm beyond mean reference external elastic membrane. Using subsequent offline volumetric IVUS measurements, dose volume histograms (DVHs) for the adventitia were determined.

Results

There were 13 restenotic lesions including four total occlusions. All recurrences localized within stented segment. The frequency of restenosis was similar between dosimetry groups (20% vs. 28%; P=.5). DVH calculations were similar in restenotic versus restenosis-free lesions. However, postprocedural IVUS minimal lumen area was significantly smaller for lesions that recurred (5.03±1.19 mm² vs. 6.13±1.7 mm²; P=.042).

Conclusions

Calculated cumulative doses delivered to the tissues do not correlate with clinical outcome. However, an adequate lumen may be important to accommodate even a small amount of recurrent intimal hyperplasia to limit restenosis and need for target lesion revascularization.