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Biomedical subjects

Mark K Eskandari

Publications and source records attributed to Mark K Eskandari.

At least 19 recordsLinked to original sources
PubMed2006

Sac behavior after aneurysm treatment with the Gore Excluder low-permeability aortic endoprosthesis: 12-month comparison to the original Excluder device.

BACKGROUND: The original Gore Excluder endoprosthesis (OGE) used both during and briefly after clinical trials was associated with less sac regression and more sac growth than some other devices, even without apparent endoleaks, presumably because of transmural movement of serous fluid across the expanded polytetrafluoroethylene material. In July 2004, the device was modified to decrease graft permeability. This study evaluated the efficacy of the new Excluder Low-Permeability Device (ELPD) at 1 year and compared it with the OGE and the Cook Zenith device (ZEN). METHODS: From Food and Drug Administration approval of the Excluder in November 2002 until June 2005, 283 patients underwent endovascular repair of abdominal aortic aneurysms with the Gore Excluder or the ZEN. Postoperative surveillance included computed tomographic scans at 1 and 12 months; 181 (64%) patients completed both scans. The 1-month computed tomographic scan served as a baseline, and the minor axis diameter, measured at the largest axial cut of the abdominal aortic aneurysm, was compared with the same measurement at 1 year. A sac size change of 5 mm or more was considered significant. Sixty patients treated with the OGE were compared with 72 patients treated with the ELPD. Forty-nine patients treated during the same time period with the ZEN, known for early sac shrinkage, were used as a reference. All measurements were performed by one observer from a digital workstation. Wilcoxon signed rank tests (pairwise) or Kruskal-Wallis tests (three groups) were used for intergroup comparison of continuous variables, whereas chi2 statistics or Fisher exact tests were used to compare categorical variables. RESULTS: Patient age and sex and mean maximum aneurysm diameter at baseline were similar among groups (P = .59, .27, and .46, respectively). Graft migration, stent fractures, acute surgical conversion, late abdominal aortic aneurysm rupture, or aneurysm-related deaths were not observed. Type II endoleak rates were similar between ELPD and ZEN (23.6% and 20.4%; P = .68). Although a higher rate of endoleaks was seen with OGE (36.7%), this was not significant when compared with the other two devices (P = .11). At 1 year, patients treated with ELPD had a sac regression rate that was significantly higher than that for patients treated with OGE (63.9% vs 25%; P < 0.001) and was similar to that for patients treated with ZEN (65.3%). Significant sac expansion was not observed with ELPD. CONCLUSIONS: At 1 year, similar to ZEN, significant aneurysm sac regression and minimal sac expansion were noted after endovascular repair of abdominal aortic aneurysms with ELPD. Low-porosity fabric used in the construction of endoprostheses seems to be an important factor in early aneurysm sac shrinkage. Long-term efficacy regarding the prevention of sac enlargement remains unclear, and further follow-up is suggested.

Aged↗
PubMed2006

Aortic arch vessel stenting: a single-center experience using cerebral protection.

HYPOTHESIS: Endovascular interventions have revolutionized the contemporary treatment of peripheral vascular occlusive disease. Traditional management of supra-aortic trunk disease has employed surgical extra-anatomic bypass via a cervical approach or median sternotomy. Endoluminal therapy may be a less morbid alternative. DESIGN AND SETTING: A retrospective review of procedures performed by vascular surgeons in an operating room angiosuite at a single university-based, tertiary referral center. PATIENTS: Eighteen consecutive patients with 20 brachiocephalic-origin stenoses. INTERVENTIONS: From December 2001 through September 2005, 20 brachiocephalic-origin stenoses were treated endoluminally with balloon-expandable stents. Treated vessels were innominate (n = 8), common carotid (n = 9), and subclavian (n = 3). The target lesion was accessed by one of the following methods: antegrade via the femoral artery (n = 5), retrograde through the brachial artery (n = 1), or via a retrograde cut-down on the common carotid artery (n = 14). Cerebral protection was achieved with either a distal embolic filter device or with open surgical occlusion of the distal common carotid artery. MAIN OUTCOME MEASURES: We report immediate and midterm outcomes of all aortic arch vessel stenting procedures with mean follow-up of 12 months. RESULTS: Mean age was 68 years (6 men and 12 women) and overall mean stenosis was 85%. Preprocedural symptoms including stroke, transient ischemic attack, arm fatigue, digital ischemia, and angina were present in 16 of 20 cases (80%). The 4 asymptomatic patients all had more than 90% stenosis on angiography. At 30-day follow-up, there were no deaths, myocardial infarctions, or strokes. During follow-up, there were no cases of restenosis. CONCLUSION: Endoluminal arterial stenting of brachiocephalic arch vessels may be a viable alternative to traditional open bypass in cases of focal stenotic disease.

Aged↗
PubMed2006

Endovascular repair of thoracic aortic tears.

BACKGROUND: Standard treatment of traumatic thoracic aortic transection (TTAT) is open repair by left thoracotomy with or without the use of partial cardiopulmonary bypass. However, open repair is associated with high rates of morbidity and mortality, particularly in multiply injured trauma patients. We reviewed our experiences of endovascular repair of acute TTAT. METHODS: Between February 2001 and February 2006, 30 patients (male 24, female 6, mean age 43 years) who had sustained severe blunt trauma with multiple injuries (mean injury severity score = 42) underwent endovascular repair for TTAT. Devices used included commercially available proximal abdominal aortic extension cuffs and thoracic stent-grafts. Either low dose or no systemic heparin was used. Arterial access was obtained by femoral-iliac cutdown (n = 19) or completely percutaneous through the femoral artery (n = 11). Mean follow-up was 11.6 months (range, 1 to 48 months). RESULTS: Technically success was achieved in 100% of patients, as determined by angiographic and computed tomographic (CT) scan exclusion of TTAT. Mean operating time was 132 minutes. Mean blood loss was 300 cm3. Three patients had complications: 1 iliac artery rupture, 1 cerebellar stroke, and 1 partial stent collapse. There were 2 perioperative deaths. There were no instances of procedure-related paralysis. Clinical and CT follow-up did not reveal evidence of endoleak, stent migration, or late pseudoaneurysm formation. CONCLUSIONS: The adaptation of commercially available stent-graft devices to treat TTAT is technically feasible, and can be performed with low rates of morbidity and mortality. The long-term durability of endovascular repair of TTAT remains unknown, but early and midterm results appear promising.

Accidents, Traffic↗
PubMed2006

Utility of left subclavian artery revascularization in association with endoluminal repair of acute and chronic thoracic aortic pathology.

BACKGROUND: A rapidly increasing number of thoracic aortic lesions are now treated by endoluminal exclusion by using stent grafts. Many of these lesions abut the great vessels and limit the length of the proximal landing zone. Various methods have been used to address this issue. We report our experience with subclavian artery revascularization in association with endoluminal repair of acute and chronic thoracic aortic pathology. METHODS: Thirty (43%) of 70 patients undergoing thoracic endovascular stent-graft placement from January 2001 to August 2005 had lesions adjacent to or involving the origin of the subclavian artery. The mean age was 62 years (range, 22-85 years; 63% were men, and 37% were women). This subgroup of 30 patients had indications for repair that included thoracic aortic aneurysm (n = 15), traumatic transection (n = 6), chronic dissection with pseudoaneurysm (n = 5), and acute dissection with intramural hematoma (n = 4). All 30 patients had the subclavian origin covered by the stent graft. In eight cases (27%), no effort was made to revascularize the subclavian artery before or during the endograft placement procedure. Twenty-three (77%) of 30 patients underwent subclavian to carotid artery transposition (n = 21) or bypass (n = 2) before (n = 12; average of 14 days before stent-graft placement), concomitant with (n = 10), or after (n = 1) the endovascular procedure. Physical examination and computed tomography scans were performed after surgery at 1, 6, and 12 months and annually thereafter. The mean follow-up was 18 months (range, 1-51 months). RESULTS: Five acute complications occurred in the eight patients (63%) who had the subclavian artery covered without pre-endograft revascularization and included four patients who experienced stroke (accounting for the only death) and one patient who developed symptomatic subclavian-vertebral steal that necessitated transposition 7 months later. Two (9%) of the 23 patients who had subclavian revascularization experienced left-sided vocal cord palsies, and 1 patient (4%) developed lower extremity paraparesis secondary to spinal cord ischemia. No late endoleaks related to retrograde sac perfusion from the most distal great vessel have been identified in any patient. CONCLUSIONS: Subclavian revascularization procedures can be performed with relatively low risk. Complications are rare, and patient recovery is rapid. Although this is not necessary in all cases, we advocate subclavian to carotid transposition when the aortic lesion is within 15 mm of the left subclavian orifice to prevent type II endoleak or perfusion of a dissected false lumen when the ipsilateral vertebral artery is patent and dominant or when coronary revascularization using an ipsilateral internal mammary artery is anticipated and in cases that necessitate extensive coverage of intercostals that contribute to spinal cord perfusion. Carotid to subclavian artery bypass should be reserved for patients with a patent internal mammary artery conduit perfusing a coronary vessel and should be combined with proximal subclavian ligation.

Acute Disease↗
PubMed2006

Decreased incidence of left common iliac vein compression in patients with abdominal aortic aneurysms.

OBJECTIVE: Compression of the left common iliac vein (LCIV) by the right common iliac artery is an anatomic variant that may increase the risk for LCIV thrombosis. The incidence of LCIV compression in patients with abdominal aortic aneurysms (AAA) is unknown, however. The aim of this descriptive anatomic study was to determine (1) the incidence of LCIV compression in patients with and without AAA and (2) if endovascular AAA repair acutely alters the incidence of LCIV compression and, hence, the risk of LCIV thrombosis. METHOD: A retrospective analysis of medical records and helical computed tomography (CT) scans was conducted in 100 AAA patients and 100 non-AAA patients (n = 200). Medical records were reviewed for symptoms and risk factors for deep vein thrombosis, and data were reported according to the Joint Society Reporting Standards for acute lower-extremity venous thrombosis. The minor diameters of the aorta, inferior vena cava, and common iliac arteries and veins were measured. For AAA patients, measurements were obtained from preoperative and 30-day postoperative CT scans. RESULTS: The mean age of the study cohort was 38 years (range, 17 to 85 years) for non-AAA subjects and 73 years (range, 51 to 89 years) for AAA subjects. The mean acute lower-extremity venous thrombosis risk factor score was low for both patient groups (non-AAA, 0.82 +/- 0.12; AAA, 2.63 +/- 0.14). Mean compression of the LCIV was 37.8% (range, 0% to 74.8%) for non-AAA patients but only 27.3% (range, 0% to 74.2%; P < .0006) for AAA patients. Of non-AAA patients with venous compression, the right common iliac artery was the compressing structure in 87% of cases. However, of AAA patients with venous compression, the left common iliac artery was the compressing structure in 76% of cases. There was no statistically significant change in the degree of compression of the LCIV before and after endovascular repair (27.3% vs 25.1%, respectively) nor was there a change in the structure that compressed the LCIV. CONCLUSION: Patients with AAA were found to have more tortuous iliac arteries that led to less anatomic compression of the LCIV compared with nonaneurysmal patients. Furthermore, the left common iliac artery was found to compress the LCIV in most of the AAA patients, and the right iliac artery was found to compress the LCIV in most non-AAA patients. Endovascular AAA repair did not acutely alter these anatomic findings. Patients with AAA may therefore be at lower risk of developing LCIV thrombosis owing to the nature of their anatomy.

Adolescent↗
PubMed2006

Stent-graft treatment of thoracoabdominal aortic aneurysms after complete visceral debranching.

Complex thoracoabdominal aortic aneurysm repair remains a difficult problem from both open and endoluminal approaches. The reduced morbidity and mortality rates reported to be associated with aortic stent-graft procedures makes this option more attractive, but it is hampered by the need for adequate proximal and distal seal zones. While branched and fenestrated aortic stent-grafts are being refined, an alternative is a two-stage surgical and endoluminal approach that is particularly useful for aneurysms involving the aortic visceral segment. The present report describes stent-graft repair in two patients after complete visceral artery revascularization or "debranching."

Aged↗
PubMed2006

Design and development of mechanical embolic protection devices.

Carotid angioplasty and stenting (CAS) is rapidly becoming an acceptable alternative to carotid endarterectomy in many patients. Much of the success of CAS is credited to advances in equipment dedicated to this minimally invasive approach. Lower profile delivery systems, tapered stent designs and most importantly, development of mechanical cerebral embolic protection devices (EPDs) have contributed to a reduction in periprocedural neurological complications that now rival results of carotid endarterectomy. Despite a lack of level one evidence in support of EPDs, a meta-analysis as well as two recent institutional reports of CAS with and without EPDs suggest a reduced stroke risk when a mechanical protection device is incorporated as part of the procedure. Since the original description by Theron and colleagues, embolic protection systems are markedly improved in ease of use and effectiveness. The three primary groups of EPDs are distal balloon occlusion, distal filtration and proximal occlusion. Although the ideal EPD has yet to materialize, this review provides insight into current design systems and the accompanying strengths and weaknesses of each.

Biomechanical Phenomena↗
PubMed2005

Duplex ultrasound remains a reliable test even after carotid stenting.

Transluminal arterial stenting reduces vessel compliance and may alter accurate interpretation of flow velocities. We reviewed duplex ultrasonography (DUS) following carotid stenting to identify criteria indicative of severe recurrent stenosis. This is a single-center retrospective review of 158 carotid stenoses treated with carotid angioplasty and stenting (CAS) from April 2001 to December 2004. DUS was obtained preoperatively, postoperatively, and at 3-month intervals thereafter. Peak systolic velocity (PSV) and end diastolic velocity (EDV) were analyzed. Mean follow-up was 12 months (range 1-40). Mean age was 71 +/- 9 years (range 51-91; 74% men, 26% women). Three patients (1.9%) developed restenosis and one (0.6%) developed an asymptomatic occlusion during follow-up. Average preoperative PSV was 373 +/- 123 cm/sec (mean +/- SD) and EDV was 148 +/- 63 cm/sec. Immediate postoperative PSV and EDV decreased by an average of 70% (average 118 +/- 45 cm/sec) and 72% (average 32 +/- 15 cm/sec), respectively. In patients free from restenosis or occlusion, these reductions (range 65-80%) were maintained throughout follow-up and remained within 1-25% of immediate postoperative values. In patients suffering restenosis or occlusion, follow-up PSV and EDV increased 34% and 28%, respectively, compared to preoperative values. PSV and EDV increased by an average of 287% and 500%, respectively, compared to immediate postoperative values. Using criteria of PSV >170 cm/sec and a 50% increase of PSV over immediate postoperative values, restenosis or occlusion was detected with 100% sensitivity and specificity in our patients. Additionally, EDV >120 cm/sec and a 50% increase in EDV over immediate postoperative values detected restenosis and occlusion with 100% sensitivity and specificity. Presumed restenosis and occlusion detected by DUS were confirmed in all cases with angiography. Restenosis or occlusion after CAS at our institution can reliably be detected by carotid duplex using cut-off values of 170 cm/sec PSV, 120 cm/sec EDV, and >50% increase over immediate postoperative values. While these criteria are applied to patients undergoing CAS at our institution, they serve only as suggested guidelines for patient populations at other centers and must be customized to each Intersocietal Commission for the Accreditation of Vascular Laboratories-accredited vascular laboratory.

Aged↗
PubMed2005

Carotid artery stenting in octogenarians: is it too risky?

Recent clinical trials have shown that the safety of carotid angioplasty and stenting (CAS) is equivalent to that of carotid endarterectomy (CEA) in high-risk patients. Despite this, the beneficial outcome in octogenarians has come under scrutiny in light of the interim results of the Carotid Artery Revascularization versus Stent Trial (CREST). We report on a single-center experience of patients > or =80 years of age compared to younger cohorts treated with CAS. CAS procedures, performed exclusively by vascular surgeons, from April 2001 to December 2004 were retrospectively reviewed. Mechanical cerebral protection with either a distal balloon occlusion system or a distal filter device was used in 140 cases and in all patients > or =80 years of age. Patients were divided into age categories: <60, 60-69, 70-79, and > or =80 years old. Data analysis included patient demographics, perioperative death, myocardial infarction, stroke, and other major complications. Statistics were derived using the SPSS program. A total of 158 procedures were performed on 151 patients. There were no statistical differences among the four groups with respect to mean stenosis or the presence of preoperative symptoms. Rates of stroke were 1 of 16 (6.25%) <60 years old, 0 of 54 (0%) age 60-69, 2 of 59 (3.4%) age 70-79, and 1 of 29 (3.4%) > or =80 years old. Preoperative symptoms were present in 6 of 29 (21%) patients > or =80 years old. Myocardial infarction and mortality rates were 0% for all groups. There were no statistical differences in stroke, death, or nonneurological complication rates among the four groups. Vascular surgeons facile at CAS should expect 30-day results comparable to CEA in all age groups. Octogenarians, whether symptomatic or asymptomatic, should not be denied this form of treatment.

Age Factors↗
PubMed2005

Enhanced abdominal aortic aneurysm in TIMP-1-deficient mice.

BACKGROUND: Matrix metalloproteinases (MMPs) are known elastolytic mediators of abdominal aortic aneurysm (AAA) degeneration, and their activity is tightly regulated by the presence of tissue inhibitors of MMPs (TIMPs). Imbalances in this system may be instrumental in compromising arterial wall integrity. The aim of this study was to show that, in an elastase-induced murine model of aneurysm formation, TIMP-1 has a protective effect. MATERIALS AND METHODS: Twenty-four wild-type (TIMP-1+/+) and 22 knockout (TIMP-1-/-) mice underwent laparotomy and isolation of the infrarenal aorta. A polyethylene catheter was inserted into the aorta and dilute pancreatic elastase (0.39 Units/ml) was infused over 5 min using a perfusion pump. Pre- and postinfusion maximal aortic diameters were obtained in triplicate for each animal using NIH Image. Final aortic measurements were obtained 14 days later, prior to perfusion fixation with 10% buffered Formalin. Aortic specimens were sectioned and stained. Statistical analysis was performed using the Student's t test. RESULTS: TIMP-1-/- mice demonstrated a significant postinfusion diameter increase compared to wild-types after elastase, which was not seen after saline infusion. At sacrifice, TIMP-1-/- mice, following both saline and elastase infusion, showed a significant increase in maximal aortic diameter relative to postinfusion measurements compared to TIMP-1+/+ mice. CONCLUSIONS: TIMP-1-/- mice develop larger aneurysms than TIMP-1+/+ mice. This study illustrates the protective effects of TIMP-1 in an experimental AAA model and may provide a means for pharmacologically controlling aneurysm growth.

Animals↗
PubMed2005

Endovascular repair of thoracic aortic pathology with custom-made devices.

BACKGROUND: Open repair of thoracic aortic aneurysms (TAAs) is fraught with high morbidity and mortality rates. The availability of endoprostheses for treating thoracic aortic pathology has not kept pace with those for treating abdominal aneurysms. Technical feasibility, durability, and safety of custom-made stent-grafts for the treatment of TAAs and dissections are evaluated. METHODS: From July 2002 to October 2004 there were 15 patients with TAAs, intramural hematoma, or dissections treated with custom-made endografts. Grafts were deployed after brief adenosine-induced cardiac arrest. Computed tomography scans were obtained 1 month postoperatively and every 6 months thereafter. The mean follow-up period was 15 months (range, 3-31 mo). RESULTS: The mean age of patients was 67 +/- 11 years (range, 47-81 y; 67% men, 33% women). Indications for repair included TAA (10), chronic type B dissection (3), penetrating ulcer (1), and acute dissection (1). Planned concomitant procedures included subclavian-carotid transposition (2) and aortosplenic bypass (2) to achieve adequate proximal or distal landing seal zones, respectively. The mean length of hospital stay was 8 days (range, 1-49 d). Immediate complications included 2 access-related events, 1 cerebellar infarction treated expectantly, and 1 death from a large hemispheric stroke. There were no cases of postoperative paralysis and on follow-up imaging no cases of endoleak, endograft migration, or stent fractures were found. No late deaths occurred caused by stent-graft repair or aneurysm-related causes. CONCLUSIONS: Endoluminal exclusion of thoracic aortic aneurysms and dissections can be achieved successfully using custom-made stent-grafts. The use of specially designed devices appears to be technically feasible and durable, with acceptable morbidity and mortality rates.

Aged↗
PubMed2005

Prospective analysis of the incidence of deep venous thrombosis in bariatric surgery patients.

BACKGROUND: Venous thromboembolism (VTE), manifest as deep venous thrombosis (DVT) or pulmonary embolus, remains an important complication in bariatric operation patients. Our purpose was to determine the incidence of VTE in a consecutive series of patients undergoing Roux-en-Y gastric bypass (RYGB) to guide appropriate therapy. METHODS: We prospectively examined a consecutive series of RYGB patients with bilateral lower-extremity venous duplex scan (DS) preoperatively, on postoperative day (POD)#2, and approximately POD#14. Preoperative clinical information including history of VTE, intraoperative data, postoperative course, and complications were recorded. Heparin 5,000 U subcutaneously was administered before the operation and every 12 hours throughout hospitalization along with sequential compression devices. Ambulation was instituted on POD#1. Temporary caval filters were placed in patients with a history of VTE. RESULTS: A total of 106 patients were examined. Body mass index was 51 +/- 8 kg/m2 (range, 40-73 kg/m2). Laparoscopic RYGB was performed in 75%. Hospital length of stay was 2.5 +/- 0.6 days. One hundred patients had no history of VTE; none had a positive DS preoperatively or on POD#2. One patient had a positive POD#14 DS and a second patient had a superficial thrombophlebitis, but a negative DS for DVT (both patients were symptomatic). Six patients had a prior history of VTE; all underwent preoperative placement of a temporary caval filter. Of these 6 patients, 1 developed a new postoperative DVT and another patient had thrombus on the caval filter with a negative lower-extremity DS. CONCLUSIONS: Occult DVT was not observed preoperatively in RYGB patients, suggesting that routine preoperative DS is not necessary in the absence of VTE history. Prophylaxis of heparin and sequential compression devices appears satisfactory in preventing DVT with only a 1% incidence in patients with no prior history of VTE. Two of the 6 patients with prior history of VTE showed evidence of thrombus postoperatively. Although a small number of patients, this finding suggests that a caval filter should be placed preoperatively in RYGB patients with a history of VTE.

Adult↗
PubMed2005

Endovascular repair of descending aortic dissections.

Endoluminal aortic stent-grafts have revolutionized the contemporary management of abdominal aortic aneurysms. The application of this treatment option for aortic dissections has been hampered by the difficult anatomic constraints frequently encountered with both acute and chronic forms of the disease. Although the data are sparse, it is rapidly growing as technologic advances are made in the design and delivery of various stent-grafts. Reviewed is our current understanding of the pathophysiology of descending thoracic aortic dissections, available stent-graft designs, techniques of implantation, and alternatives for complex anatomy. The section concludes with an overview of published data on stent-graft repair of both acute and chronic aortic dissections.

Aortic Dissection↗