Melhem J. Sharafuddin

Transvenous Closure of Secundum Atrial Septal Defects Preliminary Results With a New Self-Expanding Nitinol Prosthesis in a Swine Model

BACKGROUND Our purpose was to evaluate a new prosthesis for percutaneous closure of secundum atrial septal defects (ASDs). METHODS AND RESULTS Percutaneous closure of surgically created fossa ovalis ASD was attempted in 15 minipigs. The mean balloon-stretched ASD diameter was 12.3+/-2.3 mm (range, 10 to 16 mm). The self-expanding prosthesis was braided from 0.005-in Nitinol wires in the shape of two flat buttons with a short connecting waist with a diameter corresponding to that of the defect to be closed. Polyester filling was added to enhance thrombogenicity. Pulmonary arteriography with levo-phase was obtained before placement; immediately after placement; and at 1-week, 1-month, and 3-month follow-ups. Four animals were killed at 1 week, 1 month, and 3 months for histopathological correlation. Three deaths resulted from ventricular fibrillation (one during anesthesia and two during the placement procedure). Successful placement of the prosthesis was achieved in the remaining 12 animals. Overall immediate ASD closure on angiography occurred in 7 of 12 animals (all polyester-filled prostheses). Absent or trace shunt by angiography was present in 11 of 12 devices at 1 week, with the remaining one demonstrating a small shunt. All septal defects were completely closed at 1 month with the exception of one case in which delayed partial dislodgment of an undersized prosthesis into the right atrium had developed. Closure rate at 3 months was 100%. Neoendothelialization and fibrous incorporation of the prosthesis were completed within 1 to 3 months. CONCLUSIONS Effective and permanent occlusion of secundum ASDs is feasible with a device that offers the advantages of easy placement, self-centering, and repositionability.

Endovascular treatment of celiac and mesenteric arteries stenoses: Applications and results

PURPOSE To evaluate the safety and assess the role of endovascular therapy in a variety of conditions related to celiac and mesenteric vascular occlusive disease. Patients and methods Our retrospective study population included 25 consecutive patients (mean age, 66 years), in whom 28 procedures were performed on 26 stenosed or occluded mesenteric vessels (superior mesenteric artery [SMA] or celiac artery [CA]). Indications included chronic mesenteric ischemia (21 patients), including 2 patients who underwent stenting prior to a planned operative repair of a juxtamesenteric AAA. Three liver transplantation patients underwent stenting of an associated CA stenosis. One patient with a splenorenal bypass underwent stenting on an associated CA stenosis. The technical and clinical success rates and the incidence of complications were determined. Follow-up parameters included maintained patency on duplex sonography and sustained clinical benefit. The need for additional interventions was noted. RESULTS All procedures but one were technically successful (96%). Major complications occurred in three patients (one transient contrast-induced nephrotoxicity and two pseudoaneurysms). Immediate clinical success was achieved in 22 patients (88%). The three clinical failures included two patients with an excellent angiographic outcome, but with single-vessel moderate severity disease. Survival table analysis of delayed clinical outcome showed primary and primary-assisted clinical benefits at 11 months of 85% and 91%, respectively. Primary and primary-assisted stent patencies, as assessed by duplex sonography and/or angiography, at 6 months were both 92%. Angiographically documented restenosis occurred in three patients. Restenosis in two patients with CA stents was due to extrinsic compression, and it was without symptoms in one patient and was treated satisfactorily by restenting in the other patient. Restenosis in one patient with an SMA stent was successfully treated by restenting. CONCLUSIONS Our experience suggests a potential role for endovascular therapy of celiac and mesenteric arterial occlusive disease in a variety of clinical scenarios, with a low incidence of complications and a high technical success rate.

A Randomized, Controlled Pilot Study of Autologous CD34+ Cell Therapy for Critical Limb Ischemia

Background—Critical limb ischemia portends a risk of major amputation of 25% to 35% within 1 year of diagnosis. Preclinical studies provide evidence that intramuscular injection of autologous CD34+ cells improves limb perfusion and reduces amputation risk. In this randomized, double-blind, placebo-controlled pilot study, we evaluated the safety and efficacy of intramuscular injections of autologous CD34+ cells in subjects with moderate or high-risk critical limb ischemia, who were poor or noncandidates for surgical or percutaneous revascularization (ACT34-CLI). Methods and Results—Twenty-eight critical limb ischemia subjects were randomized and treated: 7 to 1×105 (low-dose) and 9 to 1×106 (high-dose) autologous CD34+ cells/kg; and 12 to placebo (control). Intramuscular injections were distributed into 8 sites within the ischemic lower extremity. At 6 months postinjection, 67% of control subjects experienced a major or minor amputation versus 43% of low-dose and 22% of high-dose cell-treated subjects (P=0.137). This trend continued at 12 months, with 75% of control subjects experiencing any amputation versus 43% of low-dose and 22% of high-dose cell-treated subjects (P=0.058). Amputation incidence was lower in the combined cell-treated groups compared with control group (6 months: P=0.125; 12 months: P=0.054), with the low-dose and high-dose groups individually showing trends toward improved amputation-free survival at 6 months and 12 months. No adverse safety signal was associated with cell administration. Conclusions—This study provides evidence that intramuscular administration of autologous CD34+ cells was safe in this patient population. Favorable trends toward reduced amputation rates in cell-treated versus control subjects were observed. These findings warrant further exploration in later-phase clinical trials. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00616980

Endovascular Management of Venous Thrombotic and Occlusive Diseases of the Lower Extremities

Acute complications of deep vein thrombosis (DVT) of the lower extremities include pulmonary embolism and venous ischemia. Delayed complications include a spectrum of debilitating symptoms referred to as postthrombotic syndrome (PST). Anticoagulation therapy is recognized as the mainstay of therapy in acute DVT. However, there are few data to suggest any major beneficial effect on PTS, which is thought to be mediated by valve damage and/or occlusive chronic thrombus and venous scarring. Endovascular catheter-directed thrombolysis techniques with pharmacologic thrombolytic agents, used alone or in combination with mechanical thrombectomy devices, have been proven highly effective in clearing acute DVT, which may allow the preservation of venous valve function and prevention of subsequent venous occlusive disease. Definitive management of underlying anatomic occlusive abnormalities can also be undertaken.

Rheolytic thrombectomy with use of the AngioJet-F105 catheter : Preclinical evaluation of safety

PURPOSE A preclinical evaluation of the safety of the AngioJet-F105 rheolytic thrombectomy catheter. MATERIALS AND METHODS The AngioJet-F105 catheter uses multiple retrograde high-speed fluid jets impinging on a primary aspiration lumen to create a hydrodynamic recirculation vortex that traps and fragments adjacent thrombus, with simultaneous evacuation of the resulting debris through the aspiration lumen. The effect of the AngioJet on treated vessels was evaluated in 10 canines. Vascular integrity on histopathologic examination and endothelial coverage on scanning electron microscopic study were examined in 15 vessel segments treated with the AngioJet-F105 catheter, compared with four vessel segments subjected to the Fogarty balloon maneuver, and 10 untreated vessel segments. The size distribution of particulate debris, upstream and downstream, after thrombectomy was determined in a flow-circuit model simulating the superficial femoral artery. Aliquots from the downstream effluent were then injected into the renal arteries of two healthy canines. RESULTS The device caused only minimal focal endothelial denudation and no significant deep injury. No significant difference in endothelial coverage occurred in AngioJet-treated vessel segments compared to untreated control vessels (mean +/- standard deviation: 88.0% +/- 7.9% vs 89.7% +/- 11.6%, P = .77). Vessels treated with the Fogarty balloon pullback maneuver had significantly less residual endothelial coverage (58.0% +/- 8.0%, P < .03). Particulate microemboli in the effluent of the flow model accounted for 12% of the initial thrombus volume (0% > 100 microm, 99.83% < or = 10 microm). Histopathologic evaluation of the four renal beds injected with the resulting debris demonstrated no signs of necrosis. A moderate transient increase in plasma-free hemoglobin occurred, with a mild corresponding decrease in hematocrit. CONCLUSIONS The AngioJet-F105 catheter resulted in only mild and focal injury to the treated vessels. The vast majority of resulting particulate debris consist of microscopic particles, without significant ischemic effect.

Treatment options in primary Ewing's sarcoma of the spine: report of seven cases and review of the literature.

Primary Ewings sarcoma of the spine is reviewed, and seven cases are presented. Ewings sarcoma of the spine is a rare condition that appears with a clinical triad of local pain, neurological deficit, and a palpable mass. The clinical picture, imaging characteristics, and management are discussed. The definitive management of Ewings sarcoma of the spine, as in other locations, could include three main modalities: surgery, radiotherapy, and combination chemotherapy. In the presence of acute neurological decompensation, decompressive surgery via an appropriate approach should be performed. Because Ewings sarcoma is usually sensitive to chemotherapy, initial chemotherapy, in neurologically stable patients, could be attempted first without surgical resection. Further management could then be gauged according to the response.

Long-Term Outcome following Stent Reconstruction of the Aortic Bifurcation and the Role of Geometric Determinants

We assessed the long-term patency of kissing stent reconstruction of the aortoiliac bifurcation and identified variables that may influence it. We retrospectively reviewed our experience with stent-reconstruction procedures of the aortoiliac bifurcation from January 1998 through June 2005. The impact of demographic variables, vascular risk factors, disease location and characteristics, stent material and design, and stenting configuration on stent patency was assessed using univariate and multivariate analysis. In particular, we evaluated the effect of geometric mismatch between the protruding segment of the stents and the distal aortic lumen. Sixty-six patients underwent aortobi-iliac stent reconstruction. Indications were bifurcation or bilateral proximal iliac disease in 52 patients and unilateral ostial disease requiring contralateral protection in 14 patients. Limited disease (TASC A and B) was present in 40 limbs in 19 patients; extensive/diffuse disease (TASC C and D) was present in 78 limbs in 47 patients. Complete occlusions were present in 37 limbs in 28 patients (bilateral in nine patients). Self-expanding stents were used in 56 procedures and balloon-expandable stents in 10. Crossing configuration was used in 43 procedures, while abutting configuration was used in 23 procedures. Technical success was achieved in 62 patients (94%), with all four failures due to inability to cross a chronically occluded limb. Three of these patients underwent aortomono-iliac stenting with a crossover femoral-femoral bypass graft, with the remaining one opting for no further interventions. Median combined follow-up was 37 +/- 27 months (range 0-102). Hemodynamically significant restenosis developed in nine patients (14%). The management of restenosis was endovascular in eight patients and was successful in all (balloon dilation in four, restenting in three, thrombolysis and stenting in one) and operative in one patient who developed aortic occlusion and underwent aortobifemoral grafting. Survival table analysis showed primary and assisted patency rates at 4 years of 81% and 94%, respectively. The mortality rate during follow-up was 19 (cardiac cause in eight, pulmonary cause in three, and malignancy in five). Univariate analysis showed radial mismatch (aortic lumen dead space around the protruding segment of the stents), female gender, prior occlusion, and residual stenosis to be significant predictors of restenosis. Multivariate logistic regression analysis showed radial mismatch to be the only significant determinant of restenosis, although the statistical power of the model was limited by the small number of restenoses. Stent reconstruction of the aortoiliac bifurcation for occlusive disease is effective and durable, even with complex aortoiliac disease and long segment occlusions. Most restenoses are amenable to endovascular treatment, with excellent long-term assisted patency. Geometric variables related to individual aortic anatomy and disease pattern (patient-dependent) and stenting configuration (operator-dependent) may have an impact on long-term patency.

Experimental Evaluation of a New Self-expanding Patent Ductus Arteriosus Occluder in a Canine Model

PURPOSE A new self-expanding patent ductus arteriosus (PDA) occluder was designed. MATERIALS AND METHODS Percutaneous closure of surgically created aortopulmonary shunts was attempted in 19 dogs. The occlusion device consisted of a nitinol wire frame tightly woven into a cylinder with a flat retention disc. A polyester-filled frame was used in the last six procedures. A 6-F introducing sheath was advanced across the aortopulmonary conduit into the descending thoracic aorta. The prosthesis (attached on a stiff delivery cable) was advanced through the introducing sheath. The retention disc was first released in the descending thoracic aorta, then the cylindrical device frame was expanded within the conduit by withdrawing the sheath. RESULTS Subtotal misplacement into the descending aorta occurred in one procedure (overall technical success rate, 95%), and one animal died before the 1-week follow-up. Complete angiographic shunt closure was achieved in seven of 18 (39%) animals at 30 minutes, 12 of 17 (71%) animals at 1 week, 14 of 17 (82%) animals at 1 month, and 11 of 12 (92%) animals at 3 months. Significantly higher 30-minute closure rates occurred with polyester-filled occluders compared with nonfilled occluders (five of five [100%] vs one of 13 [15%]; P = .002). Persistent shunt at 3 months occurred in only one nonfilled device (6%). In the remaining 16 animals, both orifices of the shunt were covered by a smooth glistening neoendothelium at postmortem examination. CONCLUSION This device combines the advantages of small delivery system, easy placement, self-centering, and repositionability. Immediate shunt closure can be reliably accomplished with the polyester-filled prosthesis.

Comprehensive MR evaluation of renovascular disease in five breath holds.

To detect a renal artery stenosis and assess its hemodynamic and functional significance in five breath holds. In a single MR exam, T1 weighted FLASH and T2 weighted fast spin echo techniques are used to assess renal morphology, multiphase 3D gadolinium (Gd) MRA to evaluate the renal arteries, and a segmented EPI cine phase‐contrast technique to measure renal artery blood flow. A standardized image analysis is performed to assess kidney size, corticomedullar differentiation (CMD), parenchymal enhancement, the degree of renal artery stenosis, abnormalities in blood flow pattern, and any associated abdominal vascular disease. Multiphase 3D‐Gd‐MRA accurately assesses atherosclerotic renal artery disease particularly in the presence of an associated aortic aneurysm. Delayed parenchymal enhancement, loss of CMD, and decrease in kidney size can be detected. In combination with decreased systolic velocity components, the diagnosis of a hemodynamically and functionally significant stenosis can be made. High‐resolution single‐phase 3D‐Gd‐MRA is preferable for evaluation of fibromuscular dysplasia or hypoplastic vessels. The combination of different breath hold techniques in a single, standardized MR exam allows to detect the hemodynamic and functional significance of a renal artery stenosis. J. Magn. Reson. Imaging 1999;10:347–356.

Spontaneous Extraperitoneal Hemorrhage with Hemodynamic Collapse in Patients Undergoing Anticoagulation: Management with Selective Arterial Embolization

The authors report their experience with management of unstable spontaneous extraperitoneal hemorrhage (SEH) with selective transcatheter embolization. Five consecutive patients underwent angiographic evaluation for SEH complicated by hemodynamic collapse while undergoing anticoagulation therapy. Bleeding occurred via one or two lumbar arteries in psoas hematomas. Two abdominal wall hematomas were supplied by the inferior epigastric artery, with additional supply via the deep circumflex iliac artery in one. Microcoil embolization successfully controlled extravasation in all patients, with stabilization of hemodynamic parameters. Four of the five patients survived the immediate postprocedural interval. Selective transcatheter embolization may be a viable life-saving option in SEH-associated hemodynamic collapse.