phosphorus-radioisotopes and Coronary-Stenosis

We hypothesized that restenosis after coronary stenting is predicted by elevated levels of markers of thrombus formation and inflammation. Plasma levels of representative markers of inflammation, the thrombin and plasmin activation systems and adhesion molecules were measured in 59 patients with stable angina pectoris before, immediately after and 6 hours (h), 12 h, 24 h, one month and six months after elective stent implantation (radioactive phosphorus-32 stents/RSs/ n = 16, bare-metal stents/BMSs/ n = 43). All patients underwent clinical and angiographic follow-up (FUP) six months after stenting. RSs had significantly higher angiographic severity of restenosis than BMSs (47.1 +/- 20.1% vs. 27.6 +/- 22.0%, p = 0.003). Repeated measures ANOVA revealed significant differences between the BMS and RS groups as regards the increases in plasma levels of vascular cell adhesion molecule-1 (VCAM-1, p = 0.022), plasminogen activator inhibitor-1 (PAI-1, p = 0.047), tissue-type plasminogen activator (tPA, p = 0.047) and CD40 ligand (CD40L, p = 0.038). tPA levels tended to increase immediately after stenting in both groups, whereas the PAI-1 level one month after stenting was elevated significantly only in the RS group. In the RS group, the plasma levels of CD40L were increased at 24 h and six months after stenting, and the VCAM-1 level rose immediately after stenting and remained high during the FUP. Multivariate analysis on pooled laboratory data of both groups revealed elevated levels of VCAM-1 at 12 h and at six months as significant predictors of the severity of stent restenosis. In conclusion, the process of inflammation and thrombosis occurring after coronary interventions seems to be prolonged and enhanced in patients with high-grade restenosis at the follow up.

Topics: Aged; CD40 Ligand; Chemokines; Chemokines, CXC; Coronary Restenosis; Coronary Stenosis; Female; Humans; Inflammation Mediators; Male; Middle Aged; Phosphorus Radioisotopes; Plasminogen Activator Inhibitor 1; Prognosis; Prospective Studies; Stents; Thrombosis; Time Factors; Tissue Plasminogen Activator

Acute myocardial infarction, which occurs because of the occlusion of one or more coronary arteries, is the most common form of cardiovascular disease. Balloon angioplasty is often used to treat coronary artery occlusion and is less invasive than surgery involving revascularisation of the myocardium, thus promising a better quality of life for patients. Unfortunately, the rate of re-stenosis after balloon angioplasty is high (approximately 30-50% within the first year after treatment). Intravascular radiation therapy has been used with several types of radiation source, and researchers have observed some success in decreasing the rate of re-stenosis. In this paper theoretical radiation dose distributions for monoenergetic electrons (with discrete energies) and photons are calculated for blood vessels of diameter 1.5, 3.0 and 4.5 mm with balloon and wire sources using the radiation transport code MCNP4B. Stent sources employing 32P are also simulated. Advantages and disadvantages of the radionuclides and source geometries are discussed, as well as issues regarding possible benefits to the patients.

Topics: Angioplasty, Balloon, Coronary; Coronary Stenosis; Coronary Vessels; Humans; Myocardial Infarction; Phosphorus Radioisotopes; Radioisotopes; Radiotherapy; Radiotherapy Dosage; Reproducibility of Results; Rhenium; Stents

The goal of this study was to evaluate the incidence and effects of underdosage of injured segments during intracoronary irradiation and to define the minimal length of safety margin required to avoid mismatched source placement.. Underdosage of injured segments due to misplacement of active source has been suggested as the underlying mechanism for the occurrence of edge restenosis.. Baseline angiograms of 112 vessels in 109 patients with in-stent restenosis undergoing coronary reintervention followed by intracoronary irradiation ((192)Ir: Checkmate, Cordis, Miami, Florida; (32)P: Gallileo, Guidant, Houston, Texas; (90)Sr/Y: Beta-Cath, Novoste, Norcross, Georgia) were analyzed. The distances between the outermost injury and outermost end of "reference isodose length" (RIL), defined as a segment with >/=90% of reference dose at 1 mm vessel wall depth, were measured. "Safety margin" was defined as the distance between the outermost injury and outermost end of the RIL, "geographical miss" (GM) as a complete injured segment not being covered by the RIL, and "restenosis" as the percent diameter stenosis >50%.. Baseline angiographic analysis was performed for 224 edges in 112 vessels. Geographical miss was found in 46 (20.6%) edges. The incidence of target lesion restenosis within the 78 vessels with available follow-up was 43.3% for patients with GM versus 14.9% for patients with no GM (p = 0.005). Analysis of various injured segments exposed highest restenosis rates in injured segments with negligible irradiation (27.8%) in comparison with injured segments with dose fall-off (16.7%) or injured segments with full-dose irradiation (7.7%) (p = 0.006). Receiver operating curve analysis revealed a safety margin of 10 mm required per vessel (i.e., 5-mm safety margin/edge) to achieve 95% specificity of GM.. Geographical miss is associated with a higher incidence of restenosis at the corresponding edges. Restenosis was more pronounced in injured segments with negligible irradiation than in injured segments at the dose fall-off zones. We recommend a safety margin of 10 mm per vessel to minimize GM.

Topics: Beta Particles; Coronary Angiography; Coronary Stenosis; Gamma Rays; Humans; Incidence; Iridium Radioisotopes; Myocardial Revascularization; Phosphorus Radioisotopes; Prospective Studies; Radiation Protection; Radiotherapy Dosage; Recurrence; Safety; Sensitivity and Specificity; Stents; Strontium Radioisotopes; Treatment Outcome