Longitudinal assessment of carotid atherosclerosis after Radiation Therapy using Computed Tomography: A case control Study.

OBJECTIVES: To study the carotid artery plaque composition and its volume changes in a group of patients at baseline and 2 years after head and neck radiation therapy treatment (HNXRT). METHODS: In this retrospective study, 62 patients (41 males; mean age 63 years; range 52-81) who underwent HNXRT and 40 patients (24 males; mean age 65) who underwent surgical resection of neoplasm and did not undergo HNXRT were assessed, with 2-year follow-up. The carotid artery plaque volumes, as well as the volume of the sub-components (fatty-mixed-calcified), were semiautomatically quantified. Mann-Whitney and Wilcoxon tests were used to test the hypothesis. RESULTS: In the HNXRT group, there was a statistically significant increase in the total volume of the carotid artery plaques (from 533 to 746 mm(3); p = 0.001), in the fatty plaques (103 vs. 202 mm(3); p = 0.001) and mixed plaque component volume (328 vs. 419 mm(3); p = 0.034). A statistically significant variation (from 21.8 % to 27.6 %) in the percentage of the fatty tissue was found. CONCLUSIONS: Results of this preliminary study suggest that HNXRT promotes increased carotid artery plaque volume, particularly the fatty plaque component. KEY POINTS: HNXRT increases carotid plaque volume. Plaque volume increase is mainly due to increase.in fatty plaque component. Patients who undergo HNXRT have a progression of carotid artery disease.

Angioplastia carotídea en estenosis tras radioterapia: revisión de 12 casos / Carotid angioplasty in stenosis following radiotherapy: a review of 12 cases

Introducción. La estenosis carotídea es una complicación de la radioterapia cervical. En estos casos, la angioplastia carotídea se ha planteado como el tratamiento de revascularización electivo. Sin embargo, la indicación de tratar es discutida, debido a la alta tasa de reestenosis y a los pocos estudios de evolución a largo plazo existentes. Objetivo. Presentar una serie de pacientes con estenosis carotídeas tras radioterapia tratadas mediante angioplastia con el fin de analizar su evolución a corto y largo plazo. Pacientes y métodos. De una serie de 426 pacientes con estenosis carotídeas tratadas endovascularmente, 12 pacientes (2,8%) habían recibido radioterapia previa en el cuello. Se realizó un seguimiento clínico y mediante imagen de todos ellos. Se recogió la tasa de complicaciones durante las primeras cuatro semanas y a largo plazo, y la tasa de reestenosis en el seguimiento. Resultados. El intervalo medio entre la radioterapia y la detección de estenosis fue de 14,7 años. Diez pacientes (83,3%) fueron sintomáticos. Durante las primeras cuatro semanas tras la angioplastia no se produjo ninguna complicación. El seguimiento medio fue de 45,09 meses: un 16,7% de pacientes presentó ictus, un 8,3% sufrió un infarto agudo de miocardio y un 33,3% falleció (16,6% a causa de cáncer). Al menos seis pacientes (50%) fueron diagnosticados de reestenosis; todas ellas fueron mayores o iguales al 50% y ninguna fue sintomática. Conclusiones. La angioplastia carotídea es una técnica segura y eficaz en la estenosis tras radioterapia, con escasas complicaciones a corto plazo. La tasa de restenosis carotídea es alta. La principal causa de fallecimiento es el cáncer(AU)

Introduction. Carotid stenosis is a complication of cervical radiotherapy. In these cases carotid angioplasty has been considered as the elective revascularisation treatment. Yet, the indication to treat is under discussion due to the high rate of restenosis and the scarcity of studies conducted on the long-term development. Aims. To report on a series of patients with carotid stenosis following radiotherapy who were treated by means of angioplasty, the aim being to analyse their long- and short-term development. Patients and methods. Of a series of 426 patients with carotid stenosis treated by endovascular means, 12 of them (2.8%) had previously received radiotherapy in the neck. All of them were submitted to a clinical and imaging follow-up. Data were collected concerning the rate of complications during the first four weeks and in the long term, as well as the rate of restenosis in the follow-up. Results. The mean interval between radiotherapy and the detection of stenosis was 14.7 years. Ten patients (83.3%) were symptomatic. No complications occurred during the first four weeks following the angioplasty. The mean follow-up time was 45.09 months: 16.7% of patients presented a stroke, 8.3% suffered acute myocardial infarction and 33.3% died (16.6% due to cancer). At least six patients (50%) were diagnosed with restenosis, all equal to or greater than 50% and none of them were symptomatic. Conclusions. Carotid angioplasty is a safe, effective technique in stenosis following radiotherapy, with few short-term complications. The rate of carotid restenosis is high. The main cause of death is cancer(AU)

Reproducibility of semi-automated measurement of carotid stenosis on CTA.

PURPOSE: To compare the reproducibility of semi-automated vessel analysis software to manual measurement of carotid artery stenosis on computed tomography angiography (CTA). METHODS: Two observers separately analyzed 81 carotid artery CTAs using semi-automated vessel analysis software according to a blinded protocol. The software measured the narrowest stenosis in millimeters (mm), distal internal carotid artery (ICA) in mm, and calculated percent stenosis based on NASCET criteria. One observer performed this task twice on each carotid, the second analysis delayed two months in order to mitigate recall bias. Two other observers manually measured the narrowest stenosis in mm, distal ICA in mm, and calculated NASCET percent stenosis in a blinded fashion. Correlation coefficients were calculated for each group comparing the narrowest stenosis in mm, distal ICA in mm, and NASCET percent stenosis. RESULTS: The semi-automated vessel analysis software provided excellent intraobserver correlation for narrowest stenosis in mm, distal ICA in mm, and NACSET percent stenosis (Pearson correlation coefficients of 0.985, 0.954, and 0.977 respectively). The semi-automated vessel analysis software provided excellent interobserver correlation (0.925, 0.881, and 0.892 respectively). The interobserver correlation for manual measurement was good (0.595, 0.625, and 0.555 respectively). There was a statistically significant difference in the interobserver correlation between the semi-automated vessel analysis software observers and the manual measurement observers (P < 0.001). CONCLUSION: Semi-automated vessel analysis software is a highly reproducible method of quantifying carotid artery stenosis on CTA. In this study, semi-automated vessel analysis software determination of carotid stenosis was shown to be more reproducible than manual measurement.

Peripheral vascular disease: carotid and vertebral brachytherapy for in-stent restenosis.

For years, intra-arterial brachytherapy has been a recognized method for treating recurrent stenosis after percutaneous transluminal angioplasty and stent placement. However, its use in arteries supplying the brain has not been described to date. We report a case treated with intra-arterial brachytherapy for high-grade recurrent stenoses of the high cervical internal carotid artery and the proximal vertebral artery. At 2-year follow-up, the outcome was successful.

Estenosis carotídea en pacientescon antecedentes de radioterapia cervical:orientación diagnóstica y actitud terapéutica / Carotid stenosis in patients with a history of cervical radiotherapy: diagnostic guidelines and therapeutic attitude

Objetivos. Se ha descrito una mayor prevalencia de patología carotídea en los pacientes sometidos a radioterapia cervical. Nuestro objetivo es analizar la prevalencia, la localización de la lesión y la morbimortalidad de este grupo de pacientes dentro de nuestra serie de cirugía carotídea. Pacientes y métodos. De un total de 480 casos que se intervinieron de cirugía carotídea entre 1995 y 2002, nueve pacientes (1,87 por ciento) presentaban el antecedente de radioterapia cervical. Resultados. La edad media del grupo de pacientes que se irradiaron fue de 62,4 ñ 4,1 años. La causa más frecuente de radioterapia cervical fue el carcinoma de laringe (55 por ciento). Siete pacientes (78 por ciento) presentaban una estenosis sintomática del territorio carotídeo. El 45 por ciento (cuatro) de las lesiones fueron de carótida primitiva, y el resto, de carótida interna. Se realizaron siete endarterectomías, una interposición de segmento de Dacron en la carótida primitiva y una angioplastia más un stent de la carótida primitiva. En cuanto a los resultados inmediatos, ningún paciente presentó ninguna focalidad neurológica central, y se observó una focalidad neurológica periférica transitoria en dos pacientes (25 por ciento). Los resultados tardíos con un seguimiento medio de 2,7 años, revelaron que el 100 por ciento de los pacientes permanecieron asintomáticos, y se observó una oclusión de la carótida interna a los tres años. Conclusiones. La edad media en el grupo de pacientes que se irradiaron es inferior respecto al grupo global de cirugía carotídea ( p < 0,05), y se da una mayor afectación de la carótida primitiva en este grupo. No aumenta la morbimortalidad global, y la morbilidad neurológica periférica es ligeramente superior pero reversible (AU)

Carotid brachytherapy for in-stent restenosis.

Carotid stenting has emerged as an alternative revascularization modality to endarterectomy for the treatment of carotid artery disease. Restenosis of a carotid stent may be occasionally seen. Our experience in intravascular radiation therapy for coronary restenosis has provided us the opportunity to explore this treatment strategy for carotid restenosis. We report our initial experience with brachytherapy for the treatment of restenosis after carotid stenting.

[Recurrent hypertensive crises associated with severe orthostatic hypotension due to baroreflex failure syndrome]. / Rezidivierende hypertensive Krisen verbunden mit schwerer orthostatischer Hypotonie bei Baroreflex-Insuffizienz-Syndrom.

The baroreflex mechanism is a central part of the regulation of the cardiovascular system, particularly in the control of vagal and sympathetic outflow to the heart and the peripheral circulation. Failure of the baroreflex is a rare cause of secondary hypertension. It is characterized by drastic changes in sympathetic activation and blood pressure following complete denervation of the baroreflex. Here, we report a case of baroreflex failure following bilateral carotid artery surgery and radiation. Moreover, postoperative orthostatic hypotension with recurrent syncope suggests a rare subform, the selective baroreflex failure, where efferent parasympathetic activity is preserved. Both high blood pressure and orthostatically induced syncope improved substantially after treatment with clonidine.

Assessment of cerebral hemodynamics before and after revascularization in patients with occlusive cerebrovascular disease by means of quantitative IMP-SPECT with double-injection protocol.

UNLABELLED: The purpose of this study was to validate a double-injection (DI) method with N-isopropyl-[123I]p-iodoamphetamine (IMP) to measure regional cerebral blood flow (rCBF) twice in a single session of dynamic SPECT and to elucidate a possible role of this method to identify patients with occlusive disease of major cerebral arteries, who might benefit from cerebral revascularization procedures (CR). MATERIALS AND METHODS: Fourteen patients with occlusion or severe stenosis of the internal carotid or middle cerebral artery were studied before and after CR to assess hemodynamic changes after revascularization treatment. We quantitatively measured rCBF before and after acetazolamide (ACZ) challenge along with cerebrovascular reserve capacity (CVR) with two injections of IMP in a single session of dynamic SPECT scans (DI method). The reliability and reproducibility of the DI method were validated by means of a simulation study and in eight patients who were examined without ACZ challenge to measure baseline rCBF twice. RESULTS: The analysis of simulated noisy data with realistic noise levels showed that the errors of the estimates for the first and the second rCBF and for the increase in rCBF were 2.6%, 8.1% and 10.4%, respectively. In the 8 patients examined by the DI method to measure baseline rCBF twice, the mean and the SD of percentage differences between the two consecutive measurements in rCBF were -1.3% and 5.5%, respectively. Eight out of 14 patients with occlusive disease had at least one region with a CVR less than 10%. They showed a significant increase in resting rCBF after CR, not only in the ipsilateral hemisphere (from 26.1 +/- 6.4 to 33.4 +/- 4.7) but also in the contralateral one (from 28.3 +/- 7.0 to 34.7 +/- 4.7) with a recovery of the ipsilateral CVR from 9.3 +/- 17.2 to 41.2 +/- 20.1%. The remaining six patients with good-moderate CVR did not show an increase in rCBF after CR (from 28.0 +/- 2.7 to 28.3 +/- 3.4). The three of them with a moderate CVR (10-25%) before CR showed normalization of CVR after CR. CONCLUSION: Patients with decreased rCBF and reduced CVR benefited from CR in terms of an increase in rCBF and recovery of CVR. The quantitative double-injection IMP-SPECT has the ability to identify those patients who may benefit from CR.

Comparability of the external vs internal location of radiation in inhibiting neointimal hyperplasia.

PURPOSE: One of the most controversial issues in utilizing radiation to inhibit restenosis is the importance of the location of the radiation source. The experimental results from using external forms of radiation have been contradictory and conflicting. In this study, we undertook to externally place a brachytherapy catheter source and to determine if a dose-response effect could be observed, as has been demonstrated with endovascular locations. MATERIALS AND METHODS: Neointimal hyperplasia was created in a rat carotid artery model by a balloon catheter technique. Immediately following injury, treatment groups received irradiation via an externally located high-dose rate (HDR) 192Ir brachytherapy catheter. This system allows for a more uniform dose delivery compared with endovascular radiation sources. Radiation was delivered to a 2-cm length of the injured vessel at doses of 5, 10, or 15 Gy and the animals were sacrificed at various time points following treatment (24 h to 6 months). Serial sections of tissue were stained immunohistochemically with primary antibodies for CD11b, platelet-derived growth factor (PDGF), and alpha-smooth muscle actin. RESULTS: Radiation doses of 5, 10, and 15 Gy inhibited the appearance of neointimal hyperplasia in a dose- and time-dependent manner. That is, doses of 5-15 Gy allowed for varying degrees of neointimal hyperplasia at 3 weeks posttreatment, with a greater resurgence of monocyte/macrophage activity at 5 Gy than at 10 or 15 Gy, where an absence of macrophage activity and PDGF expression was noted. From 2 to 6 months, the 10 and 15 Gy doses were again more suppressive of neointimal hyperplasia than 5 Gy, and at 6 months posttreatment the doses were approximately 25% and 50% effective, respectively. CONCLUSIONS: The demonstrated effectiveness of external brachytherapy provides "proof of principle," that it is the radiation dose delivered to the arterial wall, and not the location of the source, which is critical to a successful outcome. Ablation of the resident monocyte/macrophage population (or prevention of their activation) occurs with low to moderate doses of irradiation, leading to the absence of a cytokine cascade as evi denced by a lack of PDGF expression. A favorable therapeutic ratio exists, therefore, for radiation treatment of the arterial vasculature to prevent neointimal hyperplasia postangioplasty.

Effectiveness of fractionated external beam radiation in the inhibition of vascular restenosis.

BACKGROUND: From the clinical oncologic experience, fractionation of the radiation dose offers a better therapeutic window, both with respect to effectiveness and unwanted side effects. Thus, we undertook a pilot study in a rodent model, using a single dose of 15 Gy compared with fractionation schedules of 5 or 10 daily applications of 3 Gy. MATERIALS AND METHODS: Using a previously described rat angioplasty model, animals were randomly assigned to one of four groups: unilateral balloon injury, sham irradiation; unilateral balloon injury, bilateral 15 Gy single dose irradiation; unilateral balloon injury, bilateral 3 Gy x 5 daily fractions; or unilateral balloon injury, bilateral 3 Gy x 10 daily fractions. RESULTS AND CONCLUSIONS: All three radiation groups demonstrated a clear inhibition of neointimal hyperplasia. We therefore offer evidence for the effectiveness of fractionated radiation as a means to inhibit vascular restenosis in a rat carotid model. However, the 3 Gy x 5 schedule was less effective than either the 3 Gy x 10 schedule or the 15 Gy single dose. This study must be repeated using longer time points to provide proof of principle.