Biomedical subjects

H J Cloft

Publications and source records attributed to H J Cloft.

At least 19 recordsLinked to original sources

PubMed2007

HydroCoil for Endovascular Aneurysm Occlusion (HEAL) study: 3-6 month angiographic follow-up results.

BACKGROUND AND PURPOSE: The HydroCoil Embolic System (HES) was developed reduce recurrences of aneurysms relative to platinum coils. This study was conducted to evaluate the recurrence rate of cerebral aneurysms 3-6 months after treatment with HES. METHODS: We report the results in 135 cerebral aneurysms treated with HES in a prospective multicenter registry. Angiographic results 3-6 months after treatment were evaluated at a core laboratory. Wide variation in HES utilization within the HydroCoil for Endovascular Aneurysm Occlusion (HEAL) registry (HES representing 5% to 100% of the coil length used) allowed for subgroup analysis with regard to percentage length, last coil used, and packing attenuation in small (<10 mm) aneurysms. RESULTS: The overall recurrence rate was 38 (28.1%) of 135, which included a number of large, giant, and previously recurrent aneurysms. When HES represented > or = 75% of coil length, the recurrence rate was 0 (0%) of 18, whereas with <75% length of HES, the recurrence rate was 16 (23%) of 71 (P = .035). When the final coil deposited was a HES coil, the recurrence rate was 6 (11%) of 53, whereas when the final coil was platinum, the recurrence rate was 10 (29%) of 34 (P = .047). When the packing attenuation was > or = 50%, the recurrence rate was 11 (19%) of 59, whereas for packing attenuation <50%, the recurrence rate was 5 (18%) of 28. The packing attenuation calculations were very error-prone. CONCLUSION: Although the overall recurrence rates for small and large aneurysms in HEAL were no lower than published rates for aneurysms treated with platinum coils, patients treated in HEAL had a reduced recurrence rate when greater than 75% of the coil length used to treat an aneurysm was HES and when the final coil was HES.

Biocompatible Materials↗

PubMed2006

Long-term patency of elastase-induced aneurysm model in rabbits.

BACKGROUND AND PURPOSE: Long-term patency in untreated experimental aneurysms represents a critical attribute of any system proposed for the testing of aneurysm occlusion devices. Our purpose was to evaluate the long-term patency in elastase-induced saccular aneurysm models in rabbits. METHODS: Serial intravenous digital subtractive angiography (IVDSA) was performed in 20 elastase-induced saccular aneurysm models in rabbits 1, 3, 6, 9, 12, and 24 months after creation. Aneurysm dimensions, including neck diameter, width, and height, were measured and calculated from IVDSA images. Comparisons of the aneurysm sizes across time were performed by using the paired Wilcoxon signed rank test and the Friedman test. RESULTS: None of the 20 aneurysms showed spontaneous thrombosis at any time point. Mean dimensions did not change over time for any parameter. Mean aneurysm neck, width, and height were not significantly changed at interval evaluations of 1, 3, 6, 9, 12, and 24 months (P = .210; P = .413, and P = .405, respectively). CONCLUSION: Long-term patency in elastase-induced saccular aneurysm models in rabbits is excellent. Aneurysm dimensions remain stable for as long as 2 years following creation.

Angiography, Digital Subtraction↗

PubMed2006

HydroCoil for Endovascular Aneurysm Occlusion (HEAL) study: periprocedural results.

BACKGROUND AND PURPOSE: The HydroCoil Embolic System (HES) was developed to improve the efficacy of endovascular treatment of cerebral aneurysms. The purpose of this study is to study the periprocedural results in patients with cerebral aneurysms treated with HES. METHODS: We report the initial periprocedural results in 191 cerebral aneurysms treated with HES in the HydroCoil for Endovascular Aneurysm Occlusion, or HEAL, study. Initial aneurysm occlusion and periprocedural complication rates were evaluated and compared with historical control data regarding aneurysms treated with platinum coils. RESULTS: An initial occlusion result of "complete" or "near-complete" was achieved in 91.8% of aneurysms. Periprocedural thromboembolic events occurred in 8.1% of aneurysms treated with neurologic deficits related to thromboemboli occurring in 2.1% of aneurysms treated. Intraprocedural aneurysm perforations occurred in 2.8% of previously ruptured aneurysms, and in 0% of previously unruptured aneurysms. CONCLUSION: The initial occlusion success and complication rate when HES is used to treat cerebral aneurysms is not significantly different from platinum coils. Follow-up angiography is currently being collected and will be evaluated to determine if use of the HES reduces the rate of aneurysm recurrence.

Aneurysm, Ruptured↗

PubMed2006

A longitudinal immunohistochemical study of the healing of experimental aneurysms after embolization with platinum coils.

BACKGROUND AND PURPOSE: The purpose of this study was to probe the cellular mechanism of healing in aneurysms after platinum coil embolization, by using multiple special stains and immunolabels. METHODS: Elastase-induced aneurysms were created and embolized in 28 rabbits. Aneurysms were excised between 2 and 24 weeks after embolization. Specimens were embedded in paraffin, sectioned, and stained with hematoxylin-eosin, Masson trichrome, and multiple immunostains. RESULTS: At 2 weeks, peripheral sparse spindle-nucleated cells were positive for alpha-smooth muscle actin (SMA), myosin, and vimentin, indicating myofibroblastic differentiation. At 4 weeks, all spindle-nucleated cells in the aneurysm were positive for SMA, myosin, desmin, and vimentin. Ten weeks after embolization, positive immunohistochemical staining in the cells populating the aneurysm significantly decreased. Mean positive SMA cells, per high-powered field were 5 +/- 3, 45 +/- 9, 10 +/- 5, 0 +/- 0, and 0 +/- 0 at 2, 4, 10, 16, and 24 weeks, respectively. Findings of a Kruskal-Wallis test showed these data to be significantly different (P =.0001). Post hoc tests revealed significantly greater amounts of SMA-positive staining in the cells at 4 weeks compared with those at 2, 10, 16, and 24 weeks (P < .05). In addition, the 10-week group had significantly more positive cells than the 16- and 24-week groups (P < .05). There was a 78% decrease in apoptotic cells between 4 (37 +/- 11) and 10 weeks (8 +/- 4) after implantation. Apoptotic cells were completely absent beyond 10 weeks. CONCLUSION: Aneurysm healing, in response to platinum coil embolization, appeared to progress through the stages of thrombus formation, granulated tissue organization, and loose connective tissue formation. Myofibroblasts, the key cellular component involved in healing, appeared within the aneurysm early. They progressively reduced in number with time and finally disappeared through the mechanism of apoptosis.

Animals↗

PubMed2006

Radiation exposure to the primary operator during endovascular surgical neuroradiology procedures.

Endovascular surgical neuroradiologists can receive a substantial amount of occupational radiation exposure. We evaluated the amount of radiation exposure that results from the practice of performing hand injections during digital subtraction angiography (DSA). The primary operator can significantly decrease the radiation dose by leaving the room for DSA procedures. However, the total radiation dose for the primary operator is relatively low and is certainly within allowable regulatory limits when extrapolated to a yearly dose.

Angiography, Digital Subtraction↗

PubMed2006

The radial artery access site for interventional neuroradiology procedures.

The radial artery access site offers many advantages in neuroangiography. Right vertebral artery access is readily obtained from a right radial artery approach. As with cardiology procedures, neuroradiology procedures may necessitate the use of lytic therapy or platelet inhibitors. Sheath removal can be done without reversal of anticoagulation or concerns about major bleeding complications. We report our experience in using the radial artery access site for interventional neuroradiology cases. Practical considerations and technical details are offered.

Aged↗

PubMed2006

The value of a P value.

Explore the source record for details and available documents.

Data Interpretation, Statistical↗

PubMed2006

Bovine aortic arch variant in humans: clarification of a common misnomer.

The term "bovine arch" is widely used to describe a common anatomic variant of the human aortic arch branching. This so-called bovine aortic arch has no resemblance to the bovine aortic arch. We describe the most common human aortic arch branching patterns and compare these with the bovine aortic arch.

Anatomy, Comparative↗

PubMed2006

Can neck size in elastase-induced aneurysms be controlled? A retrospective study.

BACKGROUND AND PURPOSE: Reproducible animal models with appropriate neck size are crucial for preclinical assessment of aneurysm therapies. Our purpose was to determine whether the neck size of elastase-induced aneurysms could be controlled by adjusting the position of the temporary occlusion balloon. METHODS: Seventy-two elastase-induced aneurysms in rabbits were retrospectively analyzed. Three groups (group 1, n = 35; group 2, n = 32; group 3, n = 5) were defined according to different balloon position (lowest, intermediate, and highest, respectively) related to the origin of right common carotid artery (CCA). Aneurysm sizes in different groups were measured and compared; parent artery dilation was assessed as present or absent. The Wilcoxon rank sum test, the Fisher exact test, and the chi(2) test were used for statistics process. RESULTS: The mean aneurysm neck diameter in group 1 was significantly wider than that in group 2 (P = .0001). The proportion of wide-necked (diameter of neck >4 mm) aneurysms in group 1 was significantly higher than that in group 2 (P = .0011). The mean dome/neck ratio in group 1 was smaller than that of group 2 (P = .0031). Aneurysm width and height and the frequency of parent artery dilation were not different in groups 1 and 2 (P = .43, P = .10, and P = .25). No aneurysms formed in group 3. CONCLUSION: The neck size of elastase-induced aneurysms can be controlled by adjusting the position of the inflated balloon, with balloon positioning that bridges from the CCA to the subclavian/brachiocephalic arteries yielding narrow-necked aneurysms.

Aneurysm↗

PubMed2006

Intra-arterial digital subtraction angiography through the ear artery for experimental aneurysm imaging.

Digital subtraction angiography through the central artery of the ear was performed to show elastase-induced aneurysms in 34 rabbits. Twenty-eight (82%) aneurysms in which common origins of the bilateral common carotid artery (CCA) were found were well shown. All 6 other aneurysms not well shown had separate origins of the CCAs from the aortic arch (P < .001). This method can be used for angiographic follow-up when there is a common origin of the CCAs.

Angiography, Digital Subtraction↗

PubMed2006

Acute vertebral compression fractures in patients with multiple myeloma: evaluation of vertebral body edema patterns on MR imaging and the implications for vertebroplasty.

The presence of edema on MR imaging is a common finding in acute or subacute vertebral body compression fractures. Compression fractures can present in patients with benign osteoporosis, metastases, multiple myeloma, or hemangiomas. We present 2 patients with multiple myeloma who had symptomatic acute and subacute compression fractures documented on imaging studies without associated edema on MR imaging evaluation.

Bone Cements↗

PubMed2001

Preliminary reports and the rates of publication of follow-up reports in peer-reviewed, indexed journals.

PURPOSE: To test the hypothesis that articles published as "preliminary" or "pilot" reports are followed by more definitive publications in only a minority of cases. METHOD: A survey of Medline was performed for reports published in 1992 in journals listed in the Abridged Index Medicus that had the word "preliminary" or "pilot" in the title. For identified reports, a Medline search of publications in 1992 through 1999 was performed, using lead author's name, second author's name, and senior (last) author's name, and at least one keyword based on the publication title. Preliminary and pilot publications were subdivided by type of study (controlled clinical study, case series, laboratory or nonclinical) and by the report of either positive or negative results. Rates of publication based on study design and publication bias were compared using the chi-square test for statistical significance. RESULTS: The rate of publication of follow-up reports within seven years of the initial publication was 27%. Follow-up studies of controlled clinical studies (40%) were published more frequently than were those of laboratory or nonclinical studies (31%) or case series (22%), but these differences were not significant (p >.10). There was no statistically significant difference in follow-up publication rates based on publication bias. CONCLUSION: Only 27% of studies published as preliminary or pilot reports were subsequently followed by a more definitive publication. While the words preliminary and pilot suggest that publication of further, refined work is pending, this is often not the case.

Bibliometrics↗

PubMed2001

In vitro effects of transcatheter injection on structure, cell viability, and cell metabolism in fibroblast-impregnated alginate microspheres.

PURPOSE: To determine if microsphere-encapsulated cell preparations can be delivered through a microcatheter without compromising microsphere structure, cell viability, or metabolism. MATERIALS AND METHODS: Fibroblast-impregnated microspheres were fabricated by using 1.0% alginate and rabbit synovial fibroblasts. Fibroblast-impregnated alginate microspheres injected through microcatheters were analyzed in parallel with identical noninjected microspheres. The effects of transcatheter injection on structure and cell viability (percentage of viable cells per microsphere) were correlated with microsphere size. Structural effects were analyzed by using light microscopy, and 7-day percentage (ratio of live cells to dead cells) cell viability was assessed with confocal microscopy and fluorescent staining. In a second series of experiments, the metabolism of small microspheres was studied during a course of 7 days by using a spectrophotometric bioanalyzer. RESULTS: Transcatheter injection caused fracturing and/or fragmentation of large (800-1,000 microm) and medium (500-750 microm) microspheres, while small (250-400 microm) microspheres were structurally unaffected by transcatheter injection. Fracturing and fragmentation were associated with cell release from the alginate matrix. Although transcatheter injection reduced cell viability by 17%-23% in all size categories, it did not cause a detectable alteration in the rate of glucose metabolism. CONCLUSION: Transcatheter injection was physiologically well tolerated by fibroblasts encapsulated in alginate microspheres; however, when microsphere diameter exceeded the catheter diameter, fracturing and fragmentation of microspheres compromised the sequestration function of the microsphere vector.

Alginates↗

PubMed2001

Endovascular treatment of experimental aneurysms by use of biologically modified embolic devices: coil-mediated intraaneurysmal delivery of fibroblast tissue allografts.

BACKGROUND AND PURPOSE: Our long-term goal is to improve intraaneurysmal fibrosis after aneurysm embolization, by implanting exogenous fibroblasts, using platinum coils. For the current project, we tested two hypotheses: 1) that exogenous, fluorescence-labeled rabbit fibroblast allografts remained viable and proliferated within rabbit carotid arteries, and 2) that these fibroblast allografts could be reliably implanted into experimental aneurysms by use of platinum coils. METHODS: Part 1. New Zealand White rabbit synovial fibroblasts obtained from a commercial vender were labeled with a fluorescent membrane marker. The common carotid arteries of New Zealand White rabbits were surgically exposed, ligated proximally and distally, and entered with 22-g angiocatheters. Through the angiocatheter we injected either phosphate-buffered saline-containing fluorescence-labeled fibroblasts (treatment vessels) or saline only (control vessels). The wounds were closed, and the subjects were kept alive for various time points up to 2 weeks. After sacrifice, the carotid artery segments were resected, processed for frozen-section histologic examination, and evaluated using epifluorescent microscopy and hematoxylin and eosin staining. Cell viability and proliferation were determined by comparing the treatment versus control vessels. Part 2. A) Fluorescence-labeled cells were grown in culture on platinum coils, which were then exposed to systemic arterial flow in the rabbit thoracic aorta for various lengths of time up to 40 minutes. The coil segments were then examined using fluorescent microscopy and the presence and relative amount of cells remaining on the coil were documented. B) Experimental aneurysms in rabbits were embolized with control platinum coils (n = 9) and platinum coils bearing rabbit synovial fibroblasts that were grown onto the coils in culture prior to implantation (n = 9). Subjects were sacrificed 3, 7, and 14 days after coil implantation. Histologic samples were studied to assess the presence or absence of nucleated cells within and around coil winds in order to determine whether fibroblasts had been successfully implanted into aneurysms. Data were evaluated using the chi-square test for statistical significance. RESULTS: Part 1. Fluorescence-labeled cells were examined in the treatment carotid artery segments and results were recorded at all time intervals. The treatment vessel segments showed evidence of progressive cellular proliferation, leading to complete vessel fibrosis at 2 weeks. Conversely, control vessel segments were filled predominately with unorganized thrombus at each time interval. Part 2. A) Numerous labeled fibroblasts remained adherent to the coil despite prolonged exposure to systemic arterial flow. B) Fibroblasts were seen adjacent to or within the central lumen of coils in eight (88%) of nine aneurysms treated with cell-bearing coils. Nucleated cells were not present in any of the nine control coil subjects. This represented a statistically significant difference (P < .001). CONCLUSION: Fibroblast allografts remain viable and proliferate in the vascular space in rabbits. Furthermore, these same fibroblasts, after seeding onto platinum coils in culture, remain protected within the lumen of the coils and are retained within the coil lumen even after prolonged exposure to arterial blood flow. Coils can be used to deliver viable fibroblasts directly into experimental aneurysms successfully. These findings indicate that coil-mediated cell implantation is feasible and may be a potential method of increasing the biological activity of embolic coils.

Animals↗

PubMed2001

Bilateral type 1 proatlantal arteries with absence of vertebral arteries.

The persistent proatlantal artery is a well-described communication between the carotid and vertebrobasilar system. However, persistence of bilateral proatlantal arteries is exceptionally rare. Although usually noted as an incidental finding, the presence of a proatlantal artery, particularly when bilateral, may result in unusual symptoms or may have implications for therapy. We report a case of bilateral proatlantal arteries, describe their embryology, and consider potential clinical implications of this finding.

Angiography, Digital Subtraction↗

PubMed2001

Serial angiography in an elastase-induced aneurysm model in rabbits: evidence for progressive aneurysm enlargement after creation.

BACKGROUND AND PURPOSE: Among the several reports of elastase-induced aneurysm models, only the rabbit common carotid artery (CCA) model has been used for testing endovascular occlusion devices. Our purpose was to study the growth characteristics of an elastase-induced aneurysm model in rabbits for the purpose of determining whether delayed aneurysm enlargement occurs after creation. METHODS: Nine New Zealand White rabbits (3-4 kg) were used in this study. All study animals underwent surgery to isolate the right CCA. In three control animals, the lumen was incubated with saline and iodinated contrast material for 20 minutes. In six test animals, the lumen of the CCA was incubated with porcine elastase for 20 minutes. In all study animals, the distal right CCA was ligated. IV digital subtraction angiography was performed on postprocedural days 3, 5, 7, 14, 28, 35, 56, 84, and 112. Using an external sizing reference, the width and height of patent arterial segments at the right CCA origin were measured by two observers. For test animals, aneurysm dimensions were compared between early and late time points by using the Student's t test. RESULTS: In the control (no elastase) animals, slitlike cavities at the origin of the right CCA decreased in size over time to become nearly obliterated by 21 days. Conversely, a short segment of the proximal CCA remained widely patent in all six test animals. With the exception of a single time point in one test animal, all "aneurysm" cavities in the test animals were dilated as compared with the normal diameter of the CCA. On day 3 after surgery, the mean width and height of the aneurysm cavities in the test animals were 3.2 +/- 0.6 and 6.0 +/- 1.3 mm, respectively. Compared with dimensions at day 3, aneurysms in test animals were larger at day 14, with mean width and height of 4.1 +/- 1.7 and 8.3 +/- 1.9 mm, respectively (P =.02). Aneurysms in test animals had increased further at 21 days compared with 14 days (P =.01). Compared with measurements obtained at 21 days, dimensions remained essentially unchanged at 28 and 35 days. Thirty-five days after surgery, mean width and height were 5.0 +/- 0.9 and 10.0 +/- 2.2 mm, respectively. Follow-up imaging performed < or = 4 months after aneurysm creation showed no further change in aneurysm dimensions. CONCLUSION: Elastase incubation and vessel ligation results in patent aneurysmally dilated arterial segments at the origin of the right CCA in rabbits. These aneurysms show progressive increases in diameter over time, finally stabilizing at approximately 1 month. Our data, which show early progressive aneurysm enlargement, suggest that this model may be used for the study of systemic therapies aimed at diminishing aneurysm rest regrowth and also indicate that embolization of these model aneurysms should be delayed at least 21 days after aneurysm creation.

Aneurysm↗

PubMed2001

Use of abciximab for mediation of thromboembolic complications of endovascular therapy.

We describe four cases in which abciximab was used as a thrombolytic rescue agent in the setting of thrombotic events complicating interventional neuroradiologic procedures. After IV administration of abciximab, the thrombus resolved within 30 min in three cases, whereas no thrombolysis occurred in the fourth case despite the addition of intraarterial tissue plasminogen activator. Further evaluation of glycoprotein IIb-IIIa inhibitors in patients with cerebral thromboembolic events is necessary to prove clinical efficacy.

Abciximab↗

PubMed2000

Adjuvant use of epsilon-aminocaproic acid (Amicar) in the endovascular treatment of cranial arteriovenous fistulae.

We report our experience with the use of the antifibrinolytic agent epsilon-aminocaproic acid (EACA), Amicar, as an adjuvant to endovascular treatment of cranial arteriovenous fistulae. We also review applications of antifibrinolytic agents to neurovascular disorders and discuss the mechanism of action, dosing strategy, contraindications, and possible complications associated with the use of EACA. We identified 13 patients with cranial arteriovenous fistulae (five direct carotid cavernous fistulae [CCF], seven dural arteriovenous fistulae [DAVF], and one vein of Galen malformation) who received EACA as an adjunct to endovascular treatment. In all cases embolic coils were the primary embolic agent. We reviewed the modes of initial endovascular therapy and angiographic findings immediately thereafter and the response to EACA. Two direct CCF and two DAVF were completely thrombosed on follow-up angiography, and two DAVF demonstrated diminished flow after EACA therapy. Seven fistulae did not respond to EACA. Four of eight tightly coiled fistulae thrombosed, while none of five loosely coiled fistulae thrombosed. None of four cases with a residual fistula separate from the coil mass underwent thrombosis with EACA, while four of nine cases without a separate fistula thrombosed. There was no morbidity related to EACA therapy. EACA may thus be useful as an adjunct to endovascular treatment of cranial arteriovenous fistulae. Loose or incomplete coil packing of the fistula predicts a poor response to EACA therapy.

Adolescent↗