Mikel Sadek

Improved outcomes are associated with multilevel endovascular intervention involving the tibial vessels compared with isolated tibial intervention

OBJECTIVE Endovascular intervention is increasingly accepted as an alternative to surgery for the treatment of tibial vessel disease. Tibial vessel disease can occur in isolation or in conjunction with disease that involves the proximal lower extremity vasculature (multilevel disease). This study evaluated the overall efficacy of endovascular intervention for tibial vessel disease and whether the requirement for single-level compared with multilevel intervention affected outcomes. METHODS This study evaluated a consecutive unselected group of patients who underwent an infrapopliteal intervention from November 2002 to February 2008. The primary end points evaluated were technical success, limb salvage, primary patency, and secondary patency. The secondary end points evaluated were 30-day access site (ie, hematoma, pseudoaneurysm, and wound infection), intervention site (ie, thrombosis), and systemic (ie, acute renal failure, myocardial infarction, and mortality) complications. Patency and limb salvage were evaluated using Kaplan-Meier life-table analyses and compared using Cox regression analysis. P < .05 was considered statistically significant. RESULTS The study comprised 85 patients, 89 limbs, and 114 procedures. Age was 72.4 +/- 13.1 years, 67% were men, and follow-up was 245.8 +/- 290.8 days. The technical success rate for all procedures was 91%. Limb salvage rates for patients with critical limb ischemia at 6, 12 and 18 months were 85% +/- 0%, 81% +/- 0%, and 69% +/- 0%, respectively. For the complete patient cohort, primary patency rates at 6, 12 and 18 months were 68% +/- 6%, 50% +/- 8%, and 37% +/- 9%, respectively, and secondary patency rates were 81% +/- 5%, 71% +/- 7%, and 63% +/- 8%. Multilevel intervention was associated with significantly improved secondary patency compared with single-level intervention (P = .045). CONCLUSIONS Patency and limb salvage rates for endovascular treatment of tibial vessel disease in this study are comparable with prior reports and with historical surgical controls. Patients who undergo multilevel intervention involving the tibial vessels exhibit improved secondary patency compared with those who undergo intervention for lesions isolated to the tibial vessels. This may reflect increased distal disease burden for patients who undergo isolated tibial intervention. The study data suggest that the presence of multilevel disease should not preclude an attempt at percutaneous revascularization. Further study is required before formulating definitive recommendations for the endovascular treatment of tibial vessel disease.

Aortic Implantation of Mesenchymal Stem Cells after Aneurysm Injury in a Porcine Model

BACKGROUND Cell-based therapies are being evaluated in the setting of degenerative pathophysiologic conditions. The search for the ideal method of delivery and improvement in cell engraftment continue to pose a challenge. This study explores the feasibility of introducing mesenchymal stem cells (MSC) following aortic injury in a porcine model. METHODS Bone marrow-derived MSC were obtained from eight pigs, characterized for the MSC markers CD13 and CD 29, labeled with green fluorescent protein (GFP), and collected for autologous injection in a porcine model of abdominal aortic aneurysm (AAA). The pigs were euthanized (1-7 d) after the procedure to assess the histologic characteristics and presence of MSC in the aortic tissue. Negative controls included noninjured aorta. Tracking of the MSC was conducted by the identification of the GFP-labeled cells using immunofluorescence. RESULTS AAA sections stained with hematoxylin and eosin showed disorganization of the aortic tissue; collagen-muscle-elastin stain demonstrated fragmentation of elastin fibers. The presence of the implanted MSC in the aortic wall was evidenced by fluorescent microscopy showing GFP labeled cells. Engraftment of MSC up to 7 d after introduction was observed. CONCLUSION Autologous implantation of bone marrow-derived MSC following aortic injury in a porcine model may be successfully accomplished. The long-term impact and therapeutic value of such cell-based therapy will require further investigation.

Safety and efficacy of carotid angioplasty and stenting for radiation-associated carotid artery stenosis

INTRODUCTION Prior neck irradiation may induce atherosclerosis in the carotid artery and is considered an indication for carotid angioplasty and stenting (CAS). This study sought to evaluate the effect of neck radiation therapy (XRT) on the rate of restenosis and embolic potential in patients undergoing CAS. METHODS Two hundred ten CAS procedures were performed on 193 patients (XRT [N = 28], non-XRT [N = 182]). Mean follow-up was 347 +/- 339 days (median, 305 days; range, 16-1354 days). Duplex velocity criteria for restenosis after CAS were: >50% restenosis (peak systolic velocity [PSV] > 125 cm/sec, end diastolic velocity [EDV] 40-99 cm/sec, and internal carotid artery to common carotid artery systolic ratio [ICA/CCA] > 2.0); >70% restenosis (PSV>230 cm/sec, EDV>100 cm/sec, and ICA/CCA ratio >4.0). Restenosis >70% was confirmed by digital subtraction angiography. Additional endpoints included groin hematoma, groin pseudoaneurysm, myocardial infarction, stroke, mortality, and the combined myocardial infarction/stroke/mortality rate. Captured particulate data was obtained from microporous filters used during CAS. Nineteen XRT and 128 non-XRT consecutive filters were analyzed. Photomicroscopy was performed along three axes for each filter, and the quantity and size of the captured particles were analyzed using video image analysis software. RESULTS There were more men (XRT: 85.7% vs. non-XRT: 52.8%, P < .001) and prior surgical neck dissections in the XRT patients (XRT: 82.1% vs. non-XRT: 4.7%, P < .001). Pre-procedural stenosis did not differ significantly betweeen the two groups (XRT: 86.5% +/- 8.9% [range, 70%-99%] vs. non-XRT: 85.5% +/- 8.7% [range 70%-99%], P = NS). Perioperative outcomes, including the composite 30 day stroke/myocardial infarction/mortality rate did not differ significantly between the two groups (XRT: 0% vs. non-XRT: 3.2%, P = NS). Twelve-month freedom from restenosis rates did not differ significantly at the 50% threshold (XRT: 95.5% vs. non-XRT: 90.3%, P = NS) or at the 70% threshold (XRT: 95.5% vs. non-XRT: 96.5%, P = NS). Target lesion revascularization did not differ significantly (XRT: 0% vs. non-XRT: 0.5%, P = NS). Photomicroscopy demonstrated a trend towards increased particle number and size in the XRT filters, however the results did not achieve statistical significance: particle number (XRT: 9.8 +/- 8.4 vs. non-XRT: 9.6 +/- 11.7, P = NS), %patients with particle size >1000 microm (XRT: 47.4% vs. non-XRT: 30.5%, P = NS). CONCLUSIONS This study suggests that the durability of CAS and the characteristics of captured embolic particles are not altered by a history of neck XRT. This supports the safety and efficacy of CAS for the treatment of patients with a history of neck XRT. Prior neck XRT may predispose the patient to the de novo development of stenoses at locations that were not previously treated.

Gene expression analysis of a porcine native abdominal aortic aneurysm model

INTRODUCTION We sought to characterize the gene expression patterns occurring during the development of aneurysms in the native porcine aorta. METHODS In Yorkshire swine, the infrarenal aorta was balloon dilated and infused with a solution of type I collagenase/pancreatic porcine elastase (16,000 U/1,000 U). Aneurysmal and control aortic samples were obtained at 1 (n = 3), 2 (n = 6), and 4 (n = 5) weeks following aneurysm induction. RNA was isolated, converted to biotin-modified antisense RNA and hybridized to porcine genome arrays. Aneurysmal and control gene intensities were compared using the 2-sample-for-means z-test. P < .01 was considered statistically significant. RESULTS Extracellular matrix remodeling genes that were upregulated in aneurysmal compared with control tissue included matrix metalloproteinase-1, -2, -3, and -9; MT-MMP; cathepsin-D, -H, -K, and -S; tissue inhibitor of metalloproteinase-1; and collagen I-alpha1 chain (P < .01). Elastin exhibited temporally downregulated gene expression (P < .01). Inflammatory genes that were upregulated included intercellular adhesion molecule-2, tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-10, chemokine receptor-4, and tissue plasminogen activator (P < .01). Atherosclerosis and cancer genes that were upregulated included apolipoprotein E, acyl-CoA binding protein, friend leukemia virus integration-1, and E26 transformation-specific sequence (P < .01). CONCLUSION The porcine model replicates the gene expression patterns that are observed during the development of aneurysms in human studies as well as in rodent models. The porcine model thereby represents a novel method to study the impact of endovascular, cell-based, and other therapeutic interventions on AAA pathophysiology.

Carotid angioplasty and stenting, success relies on appropriate patient selection.

OBJECTIVE Carotid angioplasty and stenting (CAS) is a percutaneous alternative to carotid endarterectomy (CEA) for treating patients with carotid artery stenosis. This study sought to evaluate whether patients at increased perioperative risk for CEA may be treated with CAS while maintaining equivalent outcomes. METHODS This study was a nonblinded, retrospective analysis of data obtained from September 2002 to present in the CAS group and from January 1997 to present in the CEA group. Two hundred thirty-one CAS and 647 CEA procedures were performed. Patients were selected for CAS based on criteria that placed them at increased risk for standard CEA surgery. Except for percentage women treated, baseline demographics did not differ between patients treated with CAS and CEA: mean age (72.0 years [range 46-94] vs 70.5 years [range 42-92], P = NS), mean follow-up (12.8 +/- 11.8 months vs 8.7 +/- 10.0 months, P = NS) and percentage women treated (41.4% vs 32.3%, P = .03). Cerebral protection devices were used in 228/231 patients treated with CAS, and each patient underwent an NIH Stroke Scale assessment 24 hours postoperatively and at 30 days follow-up by an independent observer. RESULTS Preoperative neurologic symptoms did not differ between patients treated with CAS and CEA: amaurosis fugax (6.06% vs 6.96%, P = NS), transient ischemic attacks (13.4% vs 13.9%, P = NS), strokes (19.9% vs 14.1%, P = NS) and total symptoms (27.7% vs 30.5%, P = NS). Due to the selection of patient groups based on predefined clinical characteristics, factors associated with an increased risk of complications from standard CEA surgery were generally more prevalent in patients treated with CAS: neck irradiation (6.06% vs 1.24%, P < .001), neck dissection for cancer therapy (7.8% vs 1.5%, P < .001), prior ipsilateral CEA (15.2% vs 3.4%, P </= .001), contralateral carotid artery occlusion (12.1% vs 1.1%, P < .001), modified Goldman Cardiac Risk II-moderate risk (26.0% vs 11.3%, P < .001) and modified Goldman Cardiac Risk III-high risk (16.4% vs 2.1%, P < .001) in patients treated with CAS and CEA, respectively. Perioperative outcomes did not differ between patients treated with CAS and CEA: myocardial infarction (MI) (1.7% vs 2.6%, P = NS), stroke without residual symptoms (1.3% vs 1.2%, P = NS), stroke with residual symptoms (0.4% vs 0.8%, P = NS), mortality (0.4% vs 0.6%, P = NS), and total MI/stroke/mortality rate (3.9% vs 5.3%, P = NS). CONCLUSIONS The data in this study demonstrate that high-risk patients undergoing CAS had comparable outcomes to low-risk patients undergoing CEA. This study supports the use of CAS as a reasonable alternative for patients at increased perioperative risk for CEA.

Arteriovenous fistula after endovenous ablation for varicose veins

Endovenous ablation, using radiofrequency or laser, is becoming the mainstay of treatment for symptomatic varicose veins in the setting of saphenous vein incompetency. Both procedures have been shown to produce high rates of truncal vein occlusion with few complications. This article presents three patients who developed arteriovenous fistula (AVF) following great saphenous vein treatment: two following radiofrequency ablation (RFA) and one following laser ablation. This is the first published report of AVF following RFA for which operative details are known. We review the literature and discuss possible causes and management of this rare complication.

Preoperative relative abdominal aortic aneurysm thrombus burden predicts endoleak and sac enlargement after endovascular anerysm repair.

BACKGROUND Endoleak and sac growth remain unpredictable occurrences after EVAR, necessitating regular surveillance imaging, including CT angiography. This study was designed to identify preoperative CT variables that predict AAA remodeling and sac behavior post-EVAR. METHODS Pre- and postoperative CT scans from 136 abdominal aortic aneurysms treated with EVAR were analyzed using M2S (West Lebanon, NH) software for size measurements. Preoperative total sac volume and proportion of thrombus and calcium in the sac were assessed. Sac change was defined as a 3-mm difference in diameter and a 10-mm3 difference in volume when compared with preoperative measurements. Univariate analysis was performed for age, gender, AAA size, relative thrombus/calcium volume, device type, presence of endoleak, and the effects on sac size. RESULTS Gender, device type, age, AAA size, and percent calcium were not predictive of sac change post-EVAR. Increased proportion of thrombus on pre-EVAR resulted in a greater likelihood of sac shrinkage (P=0.002). Patients with aneurysms that grew on postoperative CT scan had less sac thrombus on pre-EVAR (mean 27.5%) than patients without evidence of endoleak (mean 41.9%, P<0.0001). Only 2 of 30 patients with >50% pre-EVAR thrombus developed endoleak. A>50% thrombus burden resulted in endoleak in significantly fewer patients (6.7%) compared with those who had <50% thrombus (43.1%). CONCLUSIONS The proportion of thrombus on preoperative CT may predict sac behavior after EVAR and development of an endoleak. Greater than 50% thrombus appears to predict absence of endoleak after EVAR. Aneurysms with large thrombus burden are less likely to grow and may require less vigilant postoperative surveillance than comparable AAA with relatively little thrombus.

Use of preoperative magnetic resonance angiography and the Artis zeego fusion program to minimize contrast during endovascular repair of an iliac artery aneurysm.

BACKGROUND A 61-year-old man with a previous endovascular repair and stage 5 chronic kidney disease presented with a symptomatic 4.5-cm left internal iliac artery aneurysm. The decision was made to proceed with endovascular repair. METHODS The preoperative magnetic resonance angiography (MRA) scan was linked to on-table rotational imaging using the Artis zeego Fusion program (Siemens AG, Forchheim, Germany). Using the fused image as a road map, we undertook coil embolization of the left internal iliac artery, and a tapered stent graft was extended from the previous graft into the external iliac artery. RESULTS Completion angiography revealed exclusion of the aneurysm sac. Three milliliters of contrast were used throughout the procedure. A follow-up magnetic resonance angiography scan at 1 month and duplex ultrasonography at 1 year revealed continued exclusion of the aneurysm sac. The patients renal function remained unchanged. CONCLUSIONS This case shows that in a patient with severe chronic kidney disease, fusion of preoperative imaging with intraoperative rotational imaging is feasible and can limit significantly the amount of contrast used during a complex endovascular procedure.

Update on Endovenous Laser Ablation 2011

In 2001, the use of endovenous laser ablation (EVLA) was introduced to the United States to treat superficial venous insufficiency. EVLA has subsequently undergone a rapid rise in popularity and usage with a concomitant decrease in traditional operative saphenectomy. Since its inception, the use of EVLA to treat superficial venous insufficiency has advanced significantly. The efficacy of treatment has been validated using both hemoglobin-specific laser wavelength and water-specific laser wavelength lasers. Currently, laser optimization is focusing on reducing postprocedural sequelae. The clinical parameters that correlate best with improved postoperative recovery use lower power/energy settings, water-specific laser wavelength lasers, and jacket or radial-emitting tips. Future study is still required to assess the durability of treatment at lower power and energy settings coupled with jacket or radial-emitting tip fibers. Long-term follow-up using duplex imaging is recommended to ensure persistent treatment success.

Are Non-Tumescent Ablation Procedures Ready to Take Over?

Tumescent anesthesia refers to the percutaneous administration of large volume anesthetic to cause the target tissue to become swollen or firm. The use of tumescent anesthesia is essential for the treatment of refluxing truncal veins using endothermal technologies. In order to obviate the use of tumescent anesthesia as an adjunct to treatment, one has to evaluate the technologies that do not employ thermal energy as the modality for treatment. These technologies include foam sclerotherapy, mechanicochemical ablation (MOCA), and the use of glue (Sapheon™ closure system). The following review juxtaposes the literature supporting the use of tumescent-based techniques to the literature supporting the use of tumescent-less techniques