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Biomedical subjects

David F Kallmes

Publications and source records attributed to David F Kallmes.

At least 19 recordsLinked to original sources
PubMed2026

Venous Sinus Stenting for Pulsatile Tinnitus: A Systematic Review and Meta-Analysis.

BACKGROUND: Pulsatile tinnitus (PT) is frequently caused by venous sinus stenosis and may be associated with idiopathic intracranial hypertension (IIH). Venous sinus stenting (VSS) directly addresses venous outflow obstruction and has emerged as a therapeutic option; however, outcome data remain heterogeneous. We performed an updated systematic review and meta-analysis to evaluate the efficacy and durability of VSS for PT and to compare outcomes between IIH-associated and isolated PT. METHODS: MEDLINE, Scopus, and Web of Science were searched from inception through December 2025 following PRISMA guidelines. Clinical studies reporting PT outcomes after VSS were included. Random-effects meta-analyses of proportions were conducted to estimate pooled rates of overall improvement, complete resolution, and recurrence. Prespecified subgroup analyses compared IIH versus isolated PT. RESULTS: Thirty-two studies comprising 850 patients were included (641 with IIH; 209 with isolated PT). Venous sinus stenosis accounted for 90.3% of treated etiologies. The pooled rate of overall PT improvement was 89.8% (95% CI, 85.5-92.9). Complete resolution occurred in 87.1% (95% CI, 82.5-90.6). Recurrence at last follow-up was 10.9% (95% CI, 8.3-14.2). Improvement and complete resolution rates did not differ significantly between IIH and isolated PT. Recurrence was higher in IIH (12.0%) than in isolated PT (5.7%), without reaching statistical significance. CONCLUSIONS: VSS is associated with high rates of PT improvement and complete resolution with low recurrence. Recurrence trends appear higher in IIH, suggesting underlying pathophysiology may influence durability.

Humans↗
PubMed2006

Balloon-assisted coiling through a 5-French system.

INTRODUCTION: We present a catheter technique that utilizes a 5F system for the purpose of balloon-assisted coiling in the setting of intracranial aneurysms. METHODS: A standard 5F short sheath is placed in the common femoral artery, and a 5F diagnostic catheter is placed through the sheath and used for selective vessel angiography. When endovascular intervention is pursued, the diagnostic catheter is placed in the appropriate vessel and systemic heparinization is ensured. Over an exchange length wire, the 5F vertebral catheter and 5F short sheath are exchanged for a 5F Shuttle (Cook) sheath. We then routinely place a 10, 14 or 18 microcatheter over an appropriately gauged microguidewire into the aneurysm. As needed, balloon catheters are then placed across the neck of the aneurysm for remodeling purposes. During the course of the procedure, control angiography is performed through the Shuttle sheath. Following the placement of coils, the microcatheter and balloon catheter are removed and a final biplane image is obtained via the 5F Shuttle sheath. RESULTS: This technique has been employed in 15 patients who required balloon-assisted coiling of an intracranial aneurysm. There were no technical difficulties or arterial access site complications from the procedures. Catheter mobility and torque were not affected, nor was the quality of our imaging. CONCLUSION: We conclude that this small-diameter system provides ample "room" for catheter placement and interventional treatment while reducing the known risks of postprocedural complications. Angiographic images remain excellent and are comparable to those obtained by larger catheters.

Balloon Occlusion↗
PubMed2006

Endovascular treatment of experimental aneurysms by use of fibroblast-coated platinum coils: an angiographic and histopathologic study.

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether implanting exogenous fibroblasts on platinum coils could enhance intra-aneurysmal fibrosis. Hypotheses included: (1) fibroblast-coated (FBC) platinum coils can improve angiographic results after embolization; and (2) FBC platinum coils can accelerate histological healing of embolized aneurysms. METHODS: Experimental aneurysms in rabbits were embolized with control platinum coils (n=18) or FBC coils (n=18). Subjects were euthanized at 14 days, 1 month, 3 months and 6 months after implantation. Digital subtraction angiography was used to evaluate stability after embolization. Histological samples were examined with a grading system (range, 0 to 12) based on neck and dome healing. RESULTS: Histology total scores and fibrosis ratio at 14 days were significantly greater in the FBC coil group compared with controls (6.6+/-1.9 versus 2.5+/-1.1, 1.2+/-0.6% versus 0.2+/-0.3%, respectively; P=0.0090). Cavities embolized with FBC coils showed cellular proliferation and thrombus organization, with an endothelialized membrane bridging the neck. There were no differences between groups in the later timepoints. The FBC coil group showed radiographic stability in 11 (61%) cases, coil compaction in 2 (11%) cases, and progressive occlusion in 5 (28%) cases. No progressive occlusion was seen in controls; 3 (17%) of 18 control cases exhibited coil compaction (P=0.0546). CONCLUSIONS: FBC coils can accelerate early histological healing compared with control coils in the rabbit aneurysm model.

Actins↗
PubMed2006

Modified technique to create morphologically reproducible elastase-induced aneurysms in rabbits.

INTRODUCTION: The purpose of this study was to create morphologically reproducible elastase-induced model aneurysms in rabbits. METHODS: We created 120 elastase-induced aneurysms in rabbits using two different methods: the standard technique (group 1, n=62) and a modified technique (group 2, n=58). In the standard technique a small cutdown with a focal area of exposure of the mid-right common carotid artery (RCCA) was employed, while in the modified technique the RCCA was completely exposed to its origin. We measured aneurysm sizes (neck diameter, width and height) in the two groups. The aneurysm sizes were compared between the two groups using Student's t test, and the standard deviations of the aneurysm sizes were compared between the groups using the F test. RESULTS: The mean aneurysm neck size, width and height in group 1 were 3.4+/-1.2 mm, 3.8+/-1.0 mm and 8.0+/-1.7 mm, respectively, and in group 2, were 3.2+/-0.9 mm, 3.7+/-0.6 mm and 9.1+/-1.8 mm, respectively. The differences in mean aneurysm neck and width between the two groups were not significant (P>0.05). However, there were significant differences in the standard deviation of these two parameters between the two groups (P<0.05 and P<0.01, respectively). The mean aneurysm height in group 2 was larger than in group 1 (P<0.001), but no significant difference in the standard deviation of this parameter between the two groups was found (P>0.05). CONCLUSION: The results indicate that more consistent aneurysm diameters can be created using the modified technique.

Animals↗
PubMed2006

Expanding the treatment window with mechanical thrombectomy in acute ischemic stroke.

INTRODUCTION: Acute ischemic stroke is a common disease associated with high mortality and significant long-term disability. Treatment options for acute ischemic stroke continue to evolve and include pharmaceutical and mechanical therapies. With the recent US Food and Drug Administration approval of a new device for mechanical thrombectomy, the options available for treatment of acute ischemic stroke have been expanded. Thrombolytic therapy is generally given intravenously in the first 3 h and up to 6 h via the intraarterial route for pharmacological clot disruption. The maximum time-frame for mechanical thrombectomy devices has yet to be determined. METHODS: A 78-year-old female presented to the emergency room with a dense right hemiparesis, leftward gaze preference and dense global aphasia. Eight hours after symptom onset, left carotid angiography confirmed a left internal carotid artery terminus occlusion. A single pass was made through the clot with an X6 Merci Retriever device. RESULTS: After a single pass, the vessel was reopened and normal flow in the left internal carotid artery was demonstrated. At the time of discharge, her neurological deficits had improved significantly. Furthermore, the final infarct area, as demonstrated on magnetic resonance imaging, was probably much smaller than it would have been if the vessel had not been recanalized. CONCLUSION: We report the use of a new mechanical thrombectomy device 8 h after onset of ischemic symptoms, with substantial subsequent improvement in neurological outcome. In selected cases, use of the Merci Retriever can result in improved outcomes beyond the traditional 6-h window used for intraarterial pharmacological thrombolysis.

Aged↗
PubMed2006

Use of the Perclose ProGlide device with the 9 French Merci retrieval system.

INTRODUCTION: Closure devices are commonly used in neurointerventional procedures to achieve groin hemostasis. These devices are particularly useful in procedures requiring anticoagulation and larger catheters. The suture-mediated Perclose ProGlide device is intended for use with 5F to 8F sheaths. We describe the use of the ProGlide device with 9F sheaths in acute stroke treatment using the Merci retrieval device. METHODS: The ProGlide device is advanced over a wire until the wire exit port is at the skin surface. The wire is removed and the device is advanced until pulsatile blood flow is encountered. The footplates are opened and the stitch is deployed. The footplates are then closed and the device is removed. After advancing the suture to the vessel, it is locked and trimmed. Firm pressure is necessary during deployment to prevent oozing around the device. If continued bleeding is encountered, direct manual pressure is used to achieve hemostasis. RESULTS: We have successfully used the Perclose ProGlide device in four patients following the Merci retriever without groin or extremity complication. The Perclose ProGlide device can be successfully used after placement of a 9F system in patients who have undergone mechanical thrombectomy. CONCLUSION: This technique may be of interest to endovascular surgical neuroradiologists because it affords fast hemostasis in large access sites following mechanical thrombectomy with the Merci retrieval device. Compared to the "Preclose" technique, it saves valuable time at the beginning of the case.

Aged, 80 and over↗
PubMed2006

Epidemiology of vertebral fractures: implications for vertebral augmentation.

To put vertebral augmentation (eg, vertebroplasty) into perspective, the etiology and outcomes of vertebral fractures are reviewed. There is considerable debate about which criteria should be used to define a vertebral fracture because there is no consistent relation between symptoms and the degree of vertebral deformity. However, it is the more significant vertebral body deformities that are most closely associated with frequent or severe back pain, and the referrals for vertebral augmentation come mainly from this subset of patients. In addition to their vertebral fractures, these patients typically have osteoporosis or elevated bone turnover, and they are at greatly increased risk of subsequent fractures as a result of falling or, more often, excessive spinal loads from activities of everyday living. Additional risk factors for new vertebral fractures include the number and severity of vertebral deformities at baseline. Moreover, new fractures are most likely in nearby vertebrae, and they occur more frequently in the mid-thoracic or thoracolumbar regions of the spine. Interestingly, these are also the characteristics of the subsequent fractures of contiguous vertebrae considered by some to represent a complication of vertebral augmentation, yet they characterize vertebral fracture risk even in untreated patients. Vertebral fractures are very common among older men and postmenopausal women; they are associated with substantial morbidity and mortality; and they may have a devastating impact on the patient's quality of life. Vertebral augmentation may be able to help many of these patients, although opportunities exist to optimize management strategies with respect to the other factors that influence long-term outcomes in this patient population.

Comorbidity↗
PubMed2006

Vascular anatomic variation in rabbits.

PURPOSE: To explore the vascular anatomic variation along the aortic arch in New Zealand White rabbits with the goal of highlighting potential anatomic configurations that might be encountered in the performance of preclinical endovascular research in rabbits. MATERIALS AND METHODS: Digital subtraction angiography images of the brachiocephalic artery (BCA) and aortic arch in New Zealand White rabbits were obtained after creation of elastase-induced aneurysms at the origin of the right common carotid artery (RCCA) in 214 animals. The patterns of origin of the RCCA and left common carotid artery (LCCA), right subclavian artery (RSCA) and left subclavian artery (LSCA), and right vertebral artery (RVA) and left vertebral artery (LVA) were analyzed. RESULTS: Five predominant variations of vessel origin were identified. In 200 of 214 cases (93%), the LCCA originated from the bifurcation of the BCA and aorta. In eight cases (4%), the LCCA directly originated from the aorta. In two cases (1%), the LCCA originated from the BCA. Aberrant RSCA anatomy in which the RSCA originated from the aortic arch instead of the BCA was found in three cases (1.5%). In a single case (0.5%), aberrant RSCA anatomy with the RVA originating from the BCA was encountered. CONCLUSIONS: Anatomic variation of the BCA in New Zealand White rabbits is similar to that seen in humans. Understanding of the normal and variant anatomy of the rabbit will aid investigators who use the rabbit model for endovascular research.

Angiography, Digital Subtraction↗
PubMed2006

Vertebral endplate fractures: an indicator of the abnormal forces generated in the spine after vertebroplasty.

UNLABELLED: Vertebroplasty alters spinal biomechanics and may lead to incident vertebral fractures. The endplate localization of prevalent and incident fractures was evaluated in 86 patients. In the absence of vertebroplasty, superior endplate fractures predominate. After the procedure, inferior endplate fractures are disproportionately common in adjacent vertebrae immediately above the treated level, potentially supporting a causative relationship between vertebroplasty and incident fractures. INTRODUCTION: To determine retrospectively whether new-onset fractures after vertebroplasty tend to cluster in the endplate immediately adjacent to the cemented vertebra. MATERIALS AND METHODS: Institutional Review Board approval and patient consent for use the use of medical records were obtained for this study. We performed a retrospective review of patients with new (incident) vertebral fractures after vertebroplasty. The median age for these patients was 72.5 years, and 58 (67.4%) were women. Fractures were diagnosed on the basis of MRI or bone scan and were catalogued based on their location within the vertebral body (superior endplate, inferior endplate, or holo-vertebral). Chi(2) and generalized estimating equation (GEE) analyses were used to compare the distribution of fracture subtypes among pre-existing (prevalent) and incident fractures. RESULTS: The patients had 313 prevalent osteoporotic vertebral fractures and were treated at 137 vertebral levels. Among prevalent fractures, superior endplate fractures predominated (57% superior, 11% inferior; p < 0.0001). After vertebroplasty, 186 incident fractures developed in these 86 patients. Seventy-seven (41%) of these incident fractures occurred adjacent to treated vertebrae. Nonadjacent, incident fractures, like prevalent fractures, occurred predominantly along superior endplate. Incident fractures immediately above treated levels, however, localized disproportionately to the inferior endplate (30% superior, 57% inferior; p < 0.0001). CONCLUSIONS: There are an increased number of inferior endplate fractures of the vertebral body immediately cephalad to the treated level.

Adult↗
PubMed2005

Intra-venous digital subtraction angiography: an alternative method to intra-arterial digital subtraction angiography for experimental aneurysm imaging.

Conventional intra-arterial digital subtraction angiography (IADSA), which necessitates surgical exposure and ligation of the femoral artery, is an invasive and expensive method of evaluation for experimental elastase-induced aneurysms in rabbits. The purpose of this study was to examine and validate intra-venous digital subtraction angiography (IVDSA) as an alternative to IADSA by comparing their diagnostic accuracies. We performed both IVDSA and IADSA for 24 elastase-induced saccular aneurysms in a rabbit model, 1 month following creation. Aneurysm sizes (neck, width and height) from both the IVDSA and IADSA procedures were evaluated and measured. Comparison of the aneurysm sizes between IVDSA and IADSA were performed with the Wilcoxon paired signed-rank test. All the aneurysms were seen clearly in both the IVDSA and IADSA techniques. Mean sizes of the IVDSA aneurysm neck, width and height were 3.41 +/- 0.80 mm, 3.61 +/- 0.93 mm and 8.07 +/- 2.11 mm, respectively. Mean sizes of the IADSA aneurysm neck, width and height were 3.43 +/- 0.80 mm, 3.66 +/- 0.92 mm and 8.16 +/- 2.25 mm, respectively. No significant difference was found in the sizes of the aneurysm neck, width and height between the two groups (P = 0.311, P = 0.086 and P = 0.258, respectively). IVDSA appears to be an alternative method for evaluating elastase-induced aneurysms in rabbits.

Angiography, Digital Subtraction↗
PubMed2005

Utility of MRA and CTA in the evaluation of carotid occlusive disease.

Cervical carotid artery atherosclerotic disease is an important cause of thromboembolic stroke. Noninvasive imaging techniques have become preferred in initial diagnostic workup. We review the current approach to carotid imaging, and the clinical utility and limitations of carotid computed tomography angiography (CTA) and magnetic resonance angiography (MRA). Future directions of these modalities, including carotid plaque imaging, are also discussed.

Artifacts↗
PubMed2005

Type 1 collagen as an endovascular stent-graft material for small-diameter vessels: a biocompatibility study.

PURPOSE: To compare patency rates and degrees of neointimal hyperplasia between bovine type 1 collagen stent-grafts and uncovered control stents in small-diameter vessels (< or =4 mm). MATERIALS AND METHODS: Uncovered stainless-steel, balloon-expandable stents (n = 5) and type 1 collagen stent-grafts (n = 6) were implanted via the femoral arteries with use of 4-mm balloon catheters into the abdominal aorta of New Zealand White rabbits. Ten animals were available for follow-up. Subjects were followed for 1 month (three uncovered stents; three collagen stent-grafts) or 4 months (two uncovered stents; two collagen stent-grafts). Angiography was performed before animal sacrifice and luminal compromise was compared between groups. Histologic and immunohistochemical analysis was performed to determine presence of neointima and neointimal thickness and area; these parameters were also compared between groups. RESULTS: All stents and stent-grafts remained patent at both time points. Luminal compromise was not detectable angiographically in any subject. Maximum neointimal thickness was less than 5 mum for all subjects. Neointimal thickness and area were not statistically significantly different between groups. CONCLUSIONS: Type 1 collagen stent-grafts demonstrate excellent hemocompatibility and biocompatibility in small-diameter vessels in rabbits.

Animals↗
PubMed2005

Large symptomatic carotid body tumor resection aided by preoperative embolization and mandibular subluxation.

Carotid body tumors (CBT) are rare and usually benign neoplasms (60%-90%), originating from the mesoderm and neural ectoderm. In view of the extensive and unrelenting growth of unresected CBT, encasing vital neurovascular structures, and the significant incidence of malignancy (> or = 10%), surgical excision is the standard treatment of choice. Despite progress in CBT imaging and surgical technique, cranial nerve deficit, stroke, and death continue to affect 10% to 40% of patients undergoing curative surgical resection, particularly in large tumors proximal to the skull base. In such cases, CBT shrinkage by preoperative embolization, improved surgical access utilizing mandibular subluxation, and electroencephalographic monitoring combined with meticulous surgical technique may enable curative tumor resection, without prohibitive morbidity. In light of associated disability, preoperative acknowledgment of the ever-present substantial risk of cranial nerve injury cannot be overemphasized. We report on a patient with a large symptomatic CBT treated surgically with the aid of mandibular subluxation and preoperative embolization.

Aged↗
PubMed2005

Subarachnoid hemorrhage: neurointensive care and aneurysm repair.

Aneurysmal subarachnoid hemorrhage (SAH) is often a neurologic catastrophe. Diagnosing SAH can be challenging, and treatment is complex, sophisticated, multidisciplinary, and rarely routine. This review emphasizes treatment in the intensive care unit, surgical and endovascular therapeutic options, and the current state of treatment of major complications such as cerebral vasospasm, acute hydrocephalus, and rebleeding. Outcome assessment in survivors of SAH and controversies in screening of family members are discussed.

Angioplasty↗