PubMed Health⌕ Search

Biomedical subjects

Alan B Lumsden

Publications and source records attributed to Alan B Lumsden.

At least 109 records · Page 6Linked to original sources
PubMed2003

Acute limb ischemia secondary to myositis-induced compartment syndrome in a patient with human immunodeficiency virus infection.

Myositis, while uncommon, develops more frequently in patients with human immunodeficiency virus infection. We report a case of acute lower leg ischemia caused by myositis in such a patient. Urgent four-compartment fasciotomy of the lower leg was performed, which decompressed the compartmental hypertension and reversed the arterial ischemia. This case underscores the importance of recognizing compartment syndrome as a cause of acute limb ischemia.

Acute Disease↗
PubMed2003

Heparin-coated balloon-expandable stent reduces intimal hyperplasia in the iliac artery in baboons.

PURPOSE: To examine the effect of heparin-coated balloon-expandable iliac stent placement on intimal hyperplasia in a baboon model. MATERIALS AND METHODS: Balloon-expandable (Palmaz-Schatz) stents were placed in bilateral common iliac arteries in 20 male baboons (mean weight: 8.8 kg). In each animal, a heparin-coated iliac stent was placed on one side and the contralateral iliac artery received an uncoated stent that served as a control. The iliac artery stents were harvested at 30 days (n = 10) and 90 days (n = 10). Arteriography was performed to assess iliac patency and intravascular ultrasonography was used to determine neointimal and luminal areas. Histologic and morphometric analysis and scanning electron microscopy were performed in the stent-implanted iliac arteries. RESULTS: One animal was excluded in the 30-day group because of premature death. In the remaining nine surviving animals, seven control stents (78%) and nine heparin-coated stents (100%) remained patent. Morphometric analysis showed that the iliac arteries with heparin-coated stents had larger luminal areas (17%, P <.05), less neointimal area (26%, P <.05), lower neointima-to-media ratios (32%, P <.05), and equivalent medial areas (P =.92) compared to the control group at 30 days. In contrast, all control and heparin-coated stents were patent (100%) in the 90-day group. In that group, the heparin-coated stent group had less neointimal area (28%, P <.05), lower neointima-to-media ratios (42%, P <.05), and equivalent medial area (P =.92) and luminal area (P =.07) compared to the control group. CONCLUSIONS: The data demonstrate that heparin-coated balloon-expandable stents reduce intimal hyperplasia after iliac artery stent placement. This approach may represent a useful strategy for prolonging luminal patency after iliac stent placement.

Animals↗
PubMed2003

Transient ischemic attack due to early carotid stent thrombosis: successful rescue with rheolytic thrombectomy and systemic abciximab.

PURPOSE: To describe a successful neurorescue technique in a patient with generalized seizures followed by hemiparesis immediately after carotid artery stenting (CAS) for a postsurgical restenosis. CASE REPORT: A 65-year-old man with a symptomatic recurrent high-grade carotid stenosis after carotid endarterectomy was treated with CAS. The procedure was complicated by sudden transient ischemic attack caused by acute carotid stent thrombosis with clot propagation into the cerebral circulation. Percutaneous mechanical thrombectomy was performed with adjunctive infusion of intravenous abciximab, resulting in complete thrombus dissolution and resolution of neurological symptoms. CONCLUSIONS: Access to a mechanical thrombectomy device was essential for rapid thrombus extraction, and adjunctive abciximab aided in residual clot dissolution. As a result of this combined method of clot removal, a disastrous outcome was averted.

Abciximab↗
PubMed2002

Intraaortic stabilization of the AneuRx stent-graft system: a useful adjunct to minimize device migration.

The deployment of a Medtronic AneuRx stent-graft system for endovascular abdominal aortic aneurysm repair requires a series of precise maneuvers that include positioning the primary delivery catheter in the infrarenal aorta, retracting the graft-covering sheath, and withdrawing the stainless steel runners. The last step allows the stent-graft to fully expand and attach to the non-aneurysmal aorta and iliac arteries. Such maneuvers may cause the stent-graft to move caudally if the device is placed in a severely angulated aortic neck. We describe a simple, coaxial, stabilization technique utilizing the contralateral introducer sheath which minimizes potential caudal migration of the stent-graft in angulated aortic necks during runner withdrawal.

Aortic Aneurysm, Abdominal↗
PubMed2002

HIV protease inhibitor ritonavir induces cytotoxicity of human endothelial cells.

OBJECTIVE: Although HIV protease inhibitors have been successfully used against HIV infection, many metabolic side effects and premature cardiovascular diseases are often associated with this therapy. The mechanisms of these complications are not clear. In this study, we investigated the effect of the HIV protease inhibitor ritonavir on human endothelial cell cultures. METHODS AND RESULTS: By using nonradioactive cell proliferation and cytotoxicity assays, human endothelial cells treated with ritonavir showed a significant decrease in cell viability and an increase in cytotoxicity in a time- and dose-dependent fashion. Mitochondrial DNA was also substantially damaged with ritonavir treatment by long polymerase chain reaction analysis. In contrast, ritonavir had a very limited effect on endothelial apoptosis, as assessed by analyses of DNA fragmentation and cellular caspase-3 activity. CONCLUSIONS: These data demonstrate, for the first time, that the HIV protease inhibitor ritonavir at concentrations near clinical plasma levels is able to directly cause endothelial mitochondrial DNA damage and cell death mainly through necrosis pathways but not through apoptosis. This study suggests that HIV protease inhibitor-mediated endothelial injury may contribute to its cardiovascular complications.

Apoptosis↗
PubMed2002

Endovascular aortic aneurysm repair in patients with renal dysfunction or severe contrast allergy: utility of imaging modalities without iodinated contrast.

Contrast-enhanced imaging studies are required for preoperative evaluation in patients undergoing endovascular aortic aneurysm repair; however, the use of iodinated contrast agents may not be suitable in patients with renal dysfunction or severe contrast allergy. The objective of this study was to evaluate the utility of imaging modalities without iodinated contrast in patients undergoing endovascular aortic aneurysm repair. A total of 297 patients underwent endo vascular repair of abdominal aortic aneurysms during a 6-year period ending in August 2001. Among them, 20 patients (6.2%), who underwent imaging studies without iodinated contrast because of either renal dysfunction or severe contrast allergy formed the basis of this study. Multiple non-iodinated contrast imaging studies were used, including gadolinium-enhanced magnetic resonance angiography (MRA), non-contrast computed tomography (CT), gadolinium or carbon dioxide (CO2) aortography, and intravascular ultrasound (IVUS). Hospital records were reviewed to evaluate the imaging study, renal function, perioperative morbidity, and clinical outcome of endo vascular aortic aneurysm repair. From the results of our study we concluded that endovascular aortic aneurysm repair can be performed safely in patients with renal dysfunction or severe contrast allergy utilizing non-iodinated contrast-based imaging modalities. IVUS is a useful intraoperative imaging modality, and postoperative endoleak surveillance can be performed using duplex ultrasound scanning to avoid risk of iodinated contrast exposure.

Aged↗
PubMed2002

Endovascular aortic aneurysm operations.

Options for the treatment of abdominal and thoracic aortic aneurysms are in a state of evolutionary change. The development and continued refinement of the endoluminal approaches has decreased the need for open aortic aneurysm surgery. Endovascular stent graft technology is an area of active research in which both the delivery systems and the endografts are undergoing continued improvement so that patients with what was previously thought to be unfavorable anatomy may be treated by these means. The design and deployment techniques of the currently available endografts, as well as those in clinical trials, are presented.

Aortic Aneurysm↗
PubMed2002

Late complication of aortoiliac stent placement- atheroembolization of the lower extremities.

BACKGROUND: Atheroembolization following aortoiliac stent placement is uncommon. The purpose of this study was to examine the management and risk factors of lower extremity atheroembolization following aortoiliac stent placement for occlusive disease. MATERIALS AND METHODS: From March 1993 to February 2001, the hospital records of all patients who developed thromboembolic events following aortoiliac stent placement were reviewed. Risk factor analysis was performed by comparing with the control group, which consisted of 493 patients treated with aortoiliac stents during the study period who did not develop atheroembolic complications. Patients with cardiac etiologies or aortic aneurysms as the source of embolization as well as those who developed acute embolization following stent deployment (<30 days) were excluded. RESULTS: Atheroembolization occurred in eight patients (12 iliac artery stents and 1 aortic stent) at intervals ranging from 9 to 43 months (mean 22 months) following aortoiliac stent placement. Arteriography in all patients implicated the stented artery as the source of atheroembolism. Five corrective operations (two aorto-bifemoral bypasses, one ileofemoral bypass, and two aortoiliac endarterectomies) along with two concomitant femoropopliteal thrombectomies were performed successfully in five patients. The remaining three patients were treated with either thrombolysis and/or additional stent placement, which resulted in either iliac occlusion or recurrent embolic symptoms (P < 0.05). All 3 patients subsequently underwent bypass procedures (one ileofemoral and two femorofemoral bypasses). There was no perioperative mortality. During a mean follow-up of 16 months (range 3 to 45 months), two patients required minor amputations, whereas one required major leg amputation. No further episodes of atheroembolism occurred in the involved limbs following surgical bypass procedures. Risk factor analysis failed to identify potential variables that correlated with atheroembolism following aortoiliac stent placement. CONCLUSION: Patients with atheromatous embolization following aortoiliac stent placement should be evaluated aggressively. The treatment of choice is surgical correction or bypass with exclusion of the offending embolic source. Although intra-arterial stent placement in the atheroembolic stented iliac artery is feasible, it may provide a less durable result.

Aged↗
PubMed2002

Covered stent exclusion of dialysis access pseudoaneurysms.

BACKGROUND: The traditional repair of hemodialysis graft pseudoaneurysms has been to surgically replace that segment of involved PTFE graft material or autogenous vein. We report a novel approach to these lesions, employing a covered stent (Wallgraft) for exclusion of arteriovenous graft (AVG) and arteriovenous fistula (AVF) pseudoaneurysms. METHODS: Ten patients with AVG or AVF pseudoaneurysms were treated endoluminally by covered stent exclusion. Wallgraft implantations were performed in the operating room with interventional capabilities under local anesthesia through a percutaneous access. Follow-up included physical examination at 2 weeks and duplex ultrasound of AVG/ AVF at 6 months after surgery. RESULTS: Ten patients with pseudoaneurysmal degeneration of their AVG/AVF were identified. The mean diameter of the pseudoaneurysmal segment was 3 cm (range, 1.5-5 cm). Immediately following covered stent implantation all the patients had palpable pulses in the pseudoaneurysms despite adequate coverage by angiography. At the 2-week follow-up visit all had lost the palpable pseudoaneurysm pulsation while the AVGs remained functional in nine patients. One patient had early thrombosis of the AVG. The follow-up duplex scans at 6 months showed complete exclusion of the pseudoaneurysms in seven patients. Two patients had thrombosis of their dialysis access, at 3 weeks (n = 1) and 3 months (n = 1) post-implantation. CONCLUSION: Endovascular covered stent exclusion of AV dialysis access pseudoaneurysms is safe and technically feasible in eliminating flow through dialysis access pseudoaneurysms and represents a novel and simple approach to this common problem, prolonging the functional life of the access site.

Adult↗
PubMed2002

Management of infected hemodialysis access grafts using cryopreserved human vein allografts.

BACKGROUND: One of the most feared complications of dialysis access is prosthetic arteriovenous (AV) graft infection, which is typically treated with AV graft removal followed by a staged dialysis graft placement elsewhere. Such a treatment approach often presents a challenge since many hemodialysis-dependent patients have limited venous access that may preclude a new AV graft or dialysis catheter placement. In this article, we review the management of AV graft infection using in situ cryopreserved human vein allografts. DATA SOURCES: Functional and antigenic characteristics as well as the clinical experience of cryopreserved human vein allograft in dialysis access are reviewed. Surgical technique of in situ cryopreserved human allograft placement for infected prosthetic AV graft is also described. CONCLUSIONS: Cryopreserved vein allograft is an acceptable graft conduit in difficult hemodialysis access situations. It offers surgeons the ability to deal with the infected graft in one operative procedure with low incidence reinfection and graft patency similar to conventional prosthetic graft replacement.

Adult↗
PubMed2002

Iliac artery kinking with endovascular therapies: technical considerations.

Iliac artery tortuosity should be considered when planning endovascular interventions from a femoral approach. Stiff guide wires across tortuous iliac segments can introduce foreshortening and temporary kinking. Recognition of this phenomenon and its implications is important when making anatomic measurements before endovascular device placement, when assessing iliac runoff, and when considering adjunctive procedures after aortoiliac interventions. Two illustrative cases of external iliac artery kinking are presented, one during an abdominal aortic aneurysm endograft procedure and another encountered during stent placement in an external iliac artery dissection. In both cases, the temporary nature of the deformity was recognized, avoiding unnecessary additional intervention.

Aged↗
PubMed2002

Percutaneous bedside femorofemoral bypass grafting for acute limb ischemia caused by intra-aortic balloon pump.

Acute limb ischemia is a common, recognized complication of intra-aortic balloon pump (IABP) placement in patients with failing myocardium, and an operative femorofemoral bypass graft is often necessary in IABP-dependent patients as a means of maintaining the lower-limb perfusion. In this report, we present a minimally invasive endovascular technique for creating a percutaneous temporary femorofemoral bypass graft at bedside in patients with IABP-induced limb ischemia. This temporary bypass grafting technique may obviate a potential graft infection or wound complications associated with a formal femorofemoral bypass graft.

Acute Disease↗
PubMed2002

A prospective evaluation of hypogastric artery embolization in endovascular aortoiliac aneurysm repair.

PURPOSE: Hypogastric artery embolization (HAE) is often performed in endovascular aortoiliac aneurysm repair to prevent potential endoleak, and this can be associated with pelvic ischemic sequelae. This prospective study was performed to evaluate the clinical outcome of HAE in patients who underwent endovascular aortoiliac aneurysm repair. METHODS: During a 15-month period, 12 patients who underwent either unilateral or bilateral HAE for endovascular aortoiliac aneurysm repair were prospectively evaluated. All patients underwent preoperative and postoperative penile pressure measurement and pulse-volume recording evaluation. Angiographic features relating to pelvic collaterals and clinical outcomes relating to pelvic ischemia were evaluated. RESULTS: Unilateral HAE was performed in eight patients (67%), and bilateral HAE was performed in four patients (33%). Mean reductions in penile brachial index (PBI) after unilateral and bilateral HAE were 13 +/- 6% (not significant) and 39 +/- 14% (P <.05), respectively. Erectile dysfunction occurred in three patients for unilateral HAE (38%) and in two patients for bilateral HAE (50%), with an overall PBI reduction of 36 +/- 12% (P <.01). No significant change in thigh brachial or ankle brachial index occurred after HAE. Hip and buttock claudication occurred in four patients for unilateral HAE (50%) and in two patients for bilateral HAE (50%), with an overall PBI reduction of 18 +/- 9% (P <.05). Other associated pelvic ischemic complications after bilateral HAE included one scrotal skin sloughing (25%) that occurred 3 days after aortic endografting and one sacral decubitus (25%) that occurred 4 months after aortic endografting. With analysis of angiographic collateral patterns, diseased profunda femoral artery (PFA; >50% stenosis) was noted in four patients, all in whom post-HAE pelvic ischemic symptoms developed (P <.05). In contrast, only four of the remaining eight patients with normal or mild PFA disease had pelvic ischemic sequelae after HAE. CONCLUSION: Erectile dysfunction after HAE correlates with significant reduction in PBI. Severe pelvic ischemic symptoms are more likely to occur after bilateral HAE, which should be avoided if possible. Moreover, patients with diseased PFA are at risk of development of pelvic ischemia after HAE. Our data suggest a potential role of concomitant profundapalsty at the time of aortic endografting to improve pelvic collateral flow and reduce pelvic ischemia in this subset of patients with HAE.

Aged↗
PubMed2002

Endovascular repair of abdominal aortic aneurysms: risk stratified outcomes.

OBJECTIVE: The impact of co-morbid conditions on early and late clinical outcomes after endovascular treatment of abdominal aortic aneurysm (AAA) was assessed in concurrent cohorts of patients stratified with respect to risk for intervention. SUMMARY BACKGROUND DATA: As a minimally invasive strategy for the treatment of AAA, endovascular repair has been embraced with enthusiasm for all prospective patients who are suitable anatomical candidates because of the promise of achieving a durable result with a reduced risk of perioperative morbidity and mortality. METHODS: From April 1994 to March 2001, endovascular AAA repair was performed in 236 patients using commercially available systems. A subset of patients considered at increased risk for intervention (n = 123) were categorized, as such, based on a preexisting history of ischemic coronary artery disease, with documentation of myocardial infarction (60%) or congestive heart failure (35%), or due to the presence of chronic obstructive disease (21%), liver disease, or malignancy. RESULTS: Perioperative mortality (30-day) was 6.5% in the increased-risk patients as compared to 1.8% among those classified as low risk (P = NS). There was no difference between groups in age (74 +/- 9 years vs. 72 +/- 6 years; mean +/- SD), surgical time (235 +/- 95 minutes vs. 219 +/- 84 minutes), blood loss (457 +/- 432 mL vs. 351 +/- 273 mL), postoperative hospital stay (4.8 +/- 3.4 days vs. 4.0 +/- 3.9 days), or days in the ICU (1.3 +/- 1.8 days vs. 0.5 +/- 1.6 days). Patients at increased risk of intervention had larger aneurysms than low-risk patients (59 +/- 13 mm vs. 51 +/- 14 mm; P <.05). Stent grafts were successfully implanted in 116 (95%) increased-risk versus 107 (95%) low-risk patients (P = NS). Conversion rates to open operative repair were similar in increased-risk and low-risk groups at 3% and 5%, respectively. The initial endoleak rate was 22% versus 20%, based on the first CT performed (either at discharge or 1 month; P = NS). To date, increased-risk patients have been followed for 17.4 +/- 15 months and low-risk patients for 16.3 +/- 14 months. Kaplan-Meier analysis for cumulative patient survival demonstrated a reduced probability of survival among those patients initially classified as at increased risk for intervention (P <.05, Mantel-Cox test). Both cohorts had similar two-year primary and secondary clinical success rates of approximately 75% and 80%, respectively. CONCLUSIONS: Early and late clinical outcomes are comparable after endovascular repair of AAA, regardless of risk-stratification. Notably, 2 years after endovascular repair, at least one in five patients was classified as a clinical failure. Given the need for close life-long surveillance and the continued uncertainty associated with clinical outcome, caution is dictated in advocating endovascular treatment for the patient who is otherwise considered an ideal candidate for standard open surgical repair.

Aged↗