Biomedical subjects

Michael L Marin

Publications and source records attributed to Michael L Marin.

At least 19 recordsLinked to original sources

PubMed2007

Endovascular repair of a traumatic arteriovenous fistula 34 years after the injury: report of a case.

Penetrating extremity injuries can result in the development of arteriovenous fistulas (AVFs), whereby normal blood flow through the capillary bed is bypassed. Late complications of untreated AVFs include proximal arterial dilatation, venous congestion, congestive heart failure, and distal ischemia. We report the case of a 57-year-old man who was referred to us for treatment of a traumatic AVF with multiple sequelae, 34 years after he sustained a shrapnel injury to his right lower leg. We performed successful endovascular repair of this AVF with the patient under spinal anesthesia. Computed tomographic angiography (CTA) done 1 month and 6 months later confirmed AVF exclusion. Patients may present with sequelae of traumatic AVFs many years after their initial injury. Endovascular repair of AVFs offers several advantages over conventional repair and can be performed successfully even in the presence of complex anatomic abnormalities.

Arteriovenous Fistula↗

PubMed2006

Successful endovascular treatment of bleeding aortoenteric fistula: a case report.

Aortoenteric fistula (AEF) is an infrequent but disastrous complication of open abdominal aortic repair. Left untreated, it has a 100% fatality rate. The traditional approaches to the repair of secondary AEF (SAEF) are associated with average mortality rates of 21-59% and numerous major complications. Here, we report a case of acute gastrointestinal bleeding due to SAEF, successfully treated with endovascular stent graft repair. At 1-year follow-up, the patient was doing well without any signs of recurrent fistula. Endovascular treatment of AEF provides another treatment option that may be particularly valuable in patients whose comorbidities would preclude open repair.

Aged, 80 and over↗

PubMed2006

Endovascular treatment of complicated aortic aneurysms in patients with underlying arteriopathies.

Patients with arteriopathies including giant cell arteritis, Marfan syndrome, and Takayasu's disease are at risk for aneurysmal degeneration of the aorta. Aortic repair has been recommended for these patients to prevent rupture. The purpose of this study was to examine outcomes following endovascular stent graft (EVSG) repair of aortic aneurysms in this patient population. Over an 8-year period, 11 patients (six men, five women) with arteriopathies underwent endovascular aortic repair. The mean age was 50 (range 15-81). Diseases included Marfan syndrome (n = 6), Takayasu's disease (n = 3), and giant cell arteritis (n = 2). Success of EVSG repair was evaluated per the reporting standards of the Society for Vascular Surgery/American Association for Vascular Surgery. Follow-up was a mean of 28.9 months (range 3-68). Six patients underwent EVSG repair of the thoracic aorta, four underwent EVSG repair of the abdominal aorta, and one underwent a staged repair of the thoracic and subsequently the abdominal aorta. Six true aneurysms and six pseudoaneurysms were repaired. Eight patients had previous aortic surgery, including four with multiple aortic operations. For the 12 aneurysms treated, technical success was achieved in 11 (91.7%). One technical failure occurred due to a small iliac access vessel, requiring an eventual iliac conduit for insertion. Early complications (<30 days) occurred in three patients. Type I or III endoleak developed following two repairs (16.7%). Aneurysm expansion occurred following one repair (8.3%). No aneurysm-related deaths occurred during follow-up. EVSG repair of aortic aneurysms is feasible and can be safely performed in patients with arteriopathies. Long-term durability in this younger group of patients who carry an ongoing risk of arterial degeneration remains to be determined.

Adolescent↗

PubMed2006

Endovascular repair of a saccular infrarenal aortic aneurysm in a liver transplant patient.

Saccular infrarenal aortic aneurysms are rare lesions that usually require prompt surgical repair. In clinical situations where morbidity and mortality associated with open aortic surgery appear to be prohibitively high, an endovascular approach may serve as a life-saving alternative. We report successful endovascular repair of a symptomatic saccular infrarenal aortic aneurysm in a complicated liver transplant patient.

Angioplasty↗

PubMed2006

Endovascular thoracic aortic repair and previous or concomitant abdominal aortic repair: is the increased risk of spinal cord ischemia real?

Spinal cord ischemia after endovascular thoracic aortic repair remains a significant risk. Previous or concomitant abdominal aortic repair may increase this risk. This investigation reviews the occurrence of spinal cord ischemia after endovascular repair of the descending thoracic aorta in patients with previous or concomitant abdominal aortic repair. Over an 8-year period, 125 patients underwent endovascular exclusion of the thoracic aorta at the Mount Sinai Medical Center. Twenty-eight of these patients had previous or concomitant abdominal aortic repair. The 27 patients who underwent staged repairs all had cerebrospinal fluid (CSF) drainage during and following repair. This population was analyzed for the complication of spinal cord ischemia and factors related to its occurrence. Mean follow-up was 19.3 months (range 1-61). Spinal cord ischemia developed in four of the 28 patients (14.3%) who underwent endovascular thoracic aortic repair with previous or concomitant abdominal aortic repair, while one of 97 patients (1.0%) developed ischemia among the remaining thoracic endograft population. One patient with concomitant abdominal aortic repair developed cord ischemia that manifested 12 hr following the procedure. The remaining three patients with previous abdominal aortic repair developed more delayed-onset paralysis ranging from the third postoperative day to 7 weeks following repair. Irreversible cord ischemia occurred in three patients, with full recovery in one patient. Major complications from CSF drainage occurred in one patient (3.7%). Spinal cord ischemia occurred at a markedly higher rate in patients with previous or concomitant abdominal aortic repair. This risk continued beyond the immediate postoperative period. The benefit of perioperative and salvage CSF drainage remains to be determined.

Angioplasty↗

PubMed2006

The development of endotension is associated with increased transmission of pressure and serous components in porous expanded polytetrafluoroethylene stent-grafts: characterization using a canine model.

OBJECTIVE: This study used a canine model of abdominal aortic aneurysms (AAAs) to compare intra-aneurysmal pressure and thrombus formation after exclusion with Dacron and expanded polytetrafluoroethylene (ePTFE) stent-grafts. METHODS: Prosthetic AAAs with implanted strain-gauge pressure transducers were treated by stent-graft exclusion using Food and Drug Administration-approved devices in 10 mongrel dogs: five Dacron (AneuRx) and five ePTFE (original Excluder). Intra-aneurysmal pressure was measured over 4 weeks after AAA exclusion and indexed to the systemic pressure, represented as a percentage of a simultaneously obtained systemic pressure (value = 1.0). Magnetic resonance imaging (MRI) of the intra-aneurysmal thrombus was performed at 1, 2, and 4 weeks after exclusion and expressed as a signal-to-noise ratio (S:N) to control for background signal intensity. Comparisons of pressures and S:N between the two stent-grafts was analyzed with the Student's t test. Intra-aneurysmal thrombus was characterized histologically. RESULTS: In animals excluded with both Dacron and ePTFE stent-grafts, the intra-aneurysmal pressure was nonpulsatile and reduced to <30% of systemic pressure. Significantly greater pressure transmission was observed after AAA exclusion using ePTFE compared with Dacron stent grafts (systolic pressure: ePTFE, 0.28 +/- 0.12 vs Dacron, 0.11 +/- 0.02, P < .001; mean pressure: ePTFE, 0.16 +/- 0.08 vs Dacron, 0.06 +/- 0.02, P < .001). MRI confirmed the absence of perfusion in all aneurysms. The T1-weighted signal intensity remained persistently elevated (S:N at 1 week, 2.7 +/- 0.4 vs 2 weeks, 4.0 +/- 0.2 vs 4 weeks, 5.4 +/- 1.3) in ePTFE-treated intra-aneurysmal thrombus, suggesting an absence of thrombus organization. In contrast, progressive evolution of T1 signal intensity in aneurysms excluded by Dacron stent-grafts was consistent with maturation from intact red blood cells (S:N at 1 week, 3.3 +/- 0.4) to methemoglobin (S:N at 2 weeks, 6.1 +/- 0.8), and then hemosiderin and ferritin (S:N at 4 weeks, 2.4 +/- 0.5). Histologically, ePTFE-excluded aneurysms contained poorly organized thrombus with red blood cell fragments and haphazardly arranged fibrin deposition indicative of active remodeling and continued influx of transudated serum. In aneurysms excluded by Dacron stent-grafts, dense, mature collagenous connective tissue and organized fibrin were present, indicative of greater thrombus organization. CONCLUSIONS: Stent-graft treatment reduces intra-aneurysmal pressure to <30% of systemic pressure when no endoleak is present; however, significantly greater pressure is present in aneurysms treated with porous ePTFE stent-grafts than Dacron grafts. Histologic and MRI imaging analysis suggest that active transudation of serous blood components may be contributing to this increased intra-aneurysmal pressure.

Animals↗

PubMed2006

Abdominal aortic aneurysm sac shrinkage after endovascular aneurysm repair: correlation with chronic sac pressure measurement.

OBJECTIVES: Abdominal aortic aneurysm (AAA) sac shrinkage after endovascular aneurysm repair (EVAR) is considered to be evidence of clinical success. Exclusion of the sac from systemic pressure is the likely cause of shrinkage. We report our continuing clinical experience with the use of a permanently implantable, ultrasound-activated remote pressure transducer to measure intrasac pressure and its correlation with changes in sac diameter over time. METHODS: Over a 22-month period, 21 patients underwent EVAR of an infrarenal AAA with implantation of an ultrasound-activated remote pressure transducer fixed to the outside of the stent-graft and exposed to the excluded aortic sac. Intrasac pressures were measured directly with an intravascular catheter and by the remote sensor at the time of stent-graft deployment. Follow-up sac pressures were measured by remote sensor and compared with systemic arterial pressure at every follow-up visit. Mean follow-up was 11.4 +/- 5.0 months (range, 1 to 26 months). Twenty patients had follow-up of > or =6 months. Mean pressure index (MPI) was calculated as the ratio of mean sac pressure to mean systemic pressure. RESULTS: Pressures could be obtained at all visits in 15 of the 21 patients. Fourteen of these 15 patients had follow-up of at least 6 months. Aneurysm sac shrinkage of >5 mm was seen in seven (50%) of these 14 patients. No aneurysm enlargement was observed in any patient. The MPI was significantly lower in patients with sac shrinkage at 6 months and at final follow-up. CONCLUSIONS: Endovascular aneurysm repair results in marked reduction of sac pressure in most patients. Patients with aneurysm shrinkage after EVAR have significantly lower MPI; however, the absence of sac shrinkage does not imply persistent pressurization of the sac. Further clinical follow-up will delineate the role of long-term sac pressure monitoring in surveillance after EVAR.

Aortic Aneurysm, Abdominal↗

PubMed2006

Evolving strategies for the treatment of aortoenteric fistulas.

BACKGROUND: Aortoenteric fistulas (AEFs) are a rare but often fatal cause of gastrointestinal bleeding. Operative repair of AEF has been historically associated with extremely high morbidity and mortality. We reviewed our experience of open surgical and endovascular treatment of AEF to compare outcomes over a contemporaneous time period. METHODS: Over a 9-year period between January 1997 and January 2006, 16 patients (11 men and 5 women) were diagnosed with and treated for AEFs. Seven patients underwent open surgical repair, and nine, with anatomically suitable lesions, underwent endovascular repair. The outcome after treatment of these patients was investigated for survival, perioperative complications, length of hospital stay, and long-term disposition. RESULTS: Three primary and 13 secondary AEFs were treated. The mean time from the initial aortic operation until AEF diagnosis was 5.9 years (range, 0.7-12.2 years) for patients with secondary AEFs. The overall 30-day mortality rate was 18.8%. One intraoperative death and one in-hospital death secondary to multisystem organ failure occurred in patients undergoing open repair. One in-hospital death related to persistent sepsis occurred in the endovascular group. The overall perioperative complication rate was 50.0%. Complications in the open group included sepsis, renal failure, bowel obstruction, and pancreatitis. Complications in the endovascular group were related to persistent sepsis. The mean in-hospital length of stay was significantly longer for patients undergoing open repair compared with endovascular repair (44.0 vs 19.4 days; P = .04). Four (80%) of five patients who were discharged from the hospital in the open group were placed in skilled nursing facilities, and seven (87.5%) of eight patients discharged in the endovascular group returned home. The median overall survival after hospital discharge was 23.1 months. There were no late aneurysm-related deaths or late deaths related to septic complications. CONCLUSIONS: Patients with AEFs have limited overall survival. Endovascular therapy offers an alternative to open surgical repair, seems to be associated with decreased perioperative morbidity and mortality and a shorter in-hospital stay, and allows for acceptable survival given the presence of coexisting medical comorbidities. Furthermore, endovascular repair provides a therapeutic option to control bleeding and allow for continued intervention in a stabilized setting.

Aged↗

PubMed2006

An 8-year experience with type II endoleaks: natural history suggests selective intervention is a safe approach.

OBJECTIVE: The treatment of type II endoleaks remains controversial because little is known about their long-term natural history and impact on changes in aneurysm morphology. This study reviews type II endoleaks occurring in patients after endovascular abdominal aortic aneurysm repair (EVAR) at a single-institution over an 8-year period. METHODS: All patients undergoing EVAR who had type II endoleaks documented on follow-up imaging studies at our institution between January 1997 and March 2005 were reviewed. Data regarding patient demographics in addition to aneurysm size, device type, operative complications, and secondary interventions were reviewed. Outcomes evaluated included the rate of spontaneous sealing, freedom from secondary intervention, and aneurysm enlargement, rupture, or conversion. RESULTS: Type II endoleaks were present in 154 of 965 patients (16.0%) undergoing EVAR. Mean follow-up time was 22.0 months (range, 1 to 72 months). Fifty-five patients (35.7%) with type II endoleaks sealed spontaneously in a mean time of 14.5 months. According to Kaplan-Meier analysis, approximately 75% of type II endoleaks sealed spontaneously within a 5-year period. Nineteen patients (12.3%) with type II endoleaks were treated at a mean time of 19.9 months at the operating surgeon's discretion, including 13 with sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 65% of the patients remained free of intervention after a period of 4 years. Thirteen patients (8.4%) experienced aneurysm sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 80% of patients with type II endoleaks remained free of sac enlargement >5 mm over a 4-year period. No patients with type II endoleaks experienced rupture or required conversion to open repair during their follow-up. Cox regression analysis showed that cancer, coronary artery disease, and chronic obstructive pulmonary disease were associated with earlier spontaneous closure of the type II endoleaks (P < .05). CONCLUSIONS: We observed that type II endoleaks have a relatively benign course, and in the absence of sac expansion, can be followed for a prolonged course of time without the need for intervention. The rate of spontaneous seal continues to increase with time and, therefore, close follow-up of patients with type II endoleaks who show no signs of aneurysm expansion is a safe approach. For patients in whom the exact etiology of their endoleak is in question, dynamic imaging should be used to exclude the presence of a type I endoleak.

Adult↗

PubMed2006

Management of aneurysms involving branches of the celiac and superior mesenteric arteries: a comparison of surgical and endovascular therapy.

OBJECTIVE: Aneurysms involving branches of the superior mesenteric and celiac arteries are uncommon and require proper management to prevent rupture and death. This study compares surgical and endovascular treatment of these aneurysms and analyzes outcome. METHODS: Patients at the Mount Sinai Medical Center in New York who were treated for aneurysms in the branches of the celiac artery and superior mesenteric artery were identified through a search of the institution's medical records and endovascular database. Patient demographics, history, clinical presentation, aneurysm characteristics, treatments, and follow-up outcome were retrospectively recorded. Significant differences between patients treated by surgical or endovascular therapy were determined by using Student's t test and chi2 analysis. RESULTS: Between January 1, 1991, and July 1, 2005, 59 patients with 61 aneurysms were treated at a single institution. Twenty-four patients had surgical repair, and 35 underwent endovascular treatment, which included coil embolization and stent-graft therapy. Splenic (28) and hepatic (22) artery aneurysms predominated. Eighty-nine percent of splenic artery aneurysms were true aneurysms and were treated by endovascular and surgical procedures in near equal numbers (14 and 11, respectively). Pseudoaneurysms were significantly more likely to be treated by endovascular means (P < .01). The technical success rate of endovascular treatment for aneurysms was 89%, and failures were successfully treated by repeat coil embolization in all patients who presented for retreatment. Patients treated by endovascular techniques had a significantly higher incidence of malignancy than patients treated with open surgical techniques (P = .03). Furthermore, patients treated by endovascular means had a shorter in-hospital length of stay (2.4 vs 6.6 days, P < .001). CONCLUSION: Endovascular management of visceral aneurysms is an effective means of treating aneurysms involving branches of the celiac and superior mesenteric arteries and is particularly useful in patients with comorbidities, including cancer. It is associated with a decreased length of stay in the elective setting, and failure of primary treatment can often be successfully managed percutaneously.

Aneurysm↗

PubMed2006

Experience with endovascular abdominal aortic aneurysm repair in nonagenarians.

PURPOSE: To report a single-institution experience with endovascular abdominal aortic aneurysm (AAA) repair (EVAR) in nonagenarians. METHODS: A retrospective review was performed of all patients >90 years old undergoing EVAR over an 8-year period at a major academic medical center. The patient population was investigated for the presence of various comorbidities, initial aneurysm size, successful aneurysm exclusion, perioperative complications, disposition, endoleaks, secondary interventions, and overall survival. RESULTS: EVAR was performed in 18 male nonagenarians (mean age 92.4 years, range 90- 95). Mean aneurysm diameter was 7.3 cm (range 5.5-9.8). The cohort had an average of 3.2 comorbid conditions. Sixteen patients were treated electively, while 2 patients underwent emergent repair for contained rupture and bleeding aortoenteric fistula, respectively. Immediate technical success was 100%. Perioperative local/vascular complications occurred in 4 (22%) patients. Perioperative systemic complications occurred in 3 (17%) patients. There were 2 (11%) perioperative (<30 days) deaths. Three (17%) patients required secondary interventions. Mean survival in patients who expired during the follow-up period beyond the first 30 days was 34 months (range 8-78). Mean survival in 8 patients who are still alive is 17.4 months (range 9-39). CONCLUSION: Endovascular AAA repair in nonagenarians is associated with a high rate of technical success and relatively low morbidity rate. Survival times following successful hospital discharge are significant. Suitable patients over 90 years of age may benefit from an endovascular AAA repair.

Age Factors↗

PubMed2006

[Endovascular repair of abdominal aortic aneurysms].

Abdominal aortic aneurysms (AAA) continue to be a major source of morbidity and mortality. The transfemoral placement of endoluminal stent-grafts for the treatment of AAAs, first described in 1991, offers a minimally invasive technique for the treatment of AAAs. The technology of endovascular repair of AAAs has progressed rapidly and the approach has proven to be safe and effective in the short- to mid-term. The spectrum of patients who are candidates for endovascular repair and the devices available continue to expand. However, endovascular repair of AAAs remains a relatively novel technique, and there is still much to be learned about its long-term durability.

Aortic Aneurysm, Abdominal↗

PubMed2005

1992: Parodi, Montefiore, and the first abdominal aortic aneurysm stent graft in the United States.

In 1990 Juan C. Parodi performed the first endovascular abdominal aortic aneurysm (AAA) repair in Buenos Aires. Two years later, in 1992, Parodi and Claudio Schonholz visited Montefiore Medical Center in New York to perform with us the first endovascular AAA repair to be done in the United States. Since then the Montefiore/Einstein vascular group has performed 1522 endovascular grafts in 674 patients for many types of vascular lesions using a variety of both surgeon-made and industry-made devices. The purpose of the present article is to describe the events that surrounded the performance of the first seminal endovascular AAA repair at our institution on November 23, 1992.

Aortic Aneurysm, Abdominal↗

PubMed2005

A canine model to study the significance and hemodynamics of type II endoleaks.

OBJECTIVE: The clinical significance of Type 2 endoleak after endovascular repair of abdominal aortic aneurysms (AAA) remains incompletely delineated. This study describes the development of a novel canine model that allows for continuous monitoring of intraaneurysmal pressure in the setting of Type 2 endoleak. METHODS: Infrarenal AAA were created in 10 mongrel dogs by implanting a prosthetic aneurysm containing an intraluminal, solid-state, strain gauge pressure transducer which is able to measure pressures in both solid and liquid media. A segment of native aorta with two or more patent side branch vessels was reimplanted into the prosthetic aneurysm using a Carrel patch. Four animals had two lumbar vessels implanted; two had two lumbar vessels and the caudal mesenteric artery implanted, and four control animals had no vessels reimplanted. Retrograde flow in the aneurysmal side branches caused a Type 2 endoleak after the aneurysm was excluded from antegrade flow by deploying a stent graft. Both systemic and intra-sac pressures were measured daily for up to 90 days after endovascular exclusion and indexed to systemic pressure. Endoleak patency and flow were assessed with digital subtraction angiography, duplex ultrasound, and cine-magnetic resonance angiography (MRA). Histological characterization of the intraaneurysmal contents was performed. RESULTS: Before endovascular exclusion, the systolic, mean arterial, and pulse pressure within the aneurysmal sac closely matched that of the systemic circulation (systolic, 0.96 +/- 0.22; mean, 0.94 +/- 0.21; pulse pressure, 0.97 +/- 0.22) (R value, 0.97). Endovascular exclusion in animals with no collateral side branch vessels resulted in no endoleak and significantly reduced intraaneurysmal pressure when compared to systemic pressure, with systolic, mean arterial, and pulse pressure 0.172 +/- 0.05, 0.137 +/- 0.05, and 0.098 +/- 0.02, respectively (P < 0.001). In animals with Type 2 endoleaks, the pressures were lower than systemic pressure, but statistically significant in their difference from the control group. The systolic pressure of those with Type 2 endoleaks was 0.702 +/- 0.048; mean arterial pressure was 0.784 +/- 0.028, and pulse pressure was 0.406 +/- 0.031 when indexed to systemic pressure (P < 0.001). Cine-MRA and Duplex ultrasound documented persistent patency of the Type 2 endoleaks throughout the study period in animals with multiple side branches. CONCLUSION: Intraaneurysmal pressure in the setting of Type 2 endoleaks may be accurately determined using this canine model. Intraaneurysmal pressure is maintained at a significant level in the context of this retrograde collateral perfusion, suggesting that persistent Type 2 endoleaks are of clinical significance. This model may serve to allow further evaluation and characterization of Type 2 endoleaks.

Angiography, Digital Subtraction↗

PubMed2005

Treatment of type II endoleaks with a novel polyurethane thrombogenic foam: induction of endoleak thrombosis and elimination of intra-aneurysmal pressure in the canine model.

OBJECTIVE: The clinical significance and treatment of retrograde collateral arterial perfusion of abdominal aortic aneurysms after endovascular repair (type II endoleak) have not been completely characterized. A canine abdominal aortic aneurysm model of type II endoleak with an implanted pressure transducer was used to evaluate the use of polyurethane foam to induce thrombosis of type II endoleaks. The effect on endoleak patency, intra-aneurysmal pressure, and thrombus histology was studied. METHODS: Prosthetic aneurysms with an intraluminal, solid-state, strain-gauge pressure transducer were created in the infrarenal aorta of 14 mongrel dogs. Aneurysm side-branch vessels were reimplanted into the prosthetic aneurysm of 10 animals by using a Carrel patch. Type II (retrograde) endoleaks were created by excluding the aneurysm from antegrade perfusion with an impermeable stent graft. Thrombosis of the type II endoleak was induced by implantation of polyurethane foam into the prosthetic aneurysm sac of four animals. Six animals with type II endoleaks were not treated. In four control animals, no collateral side branches were reimplanted, and therefore no endoleak was created. Intra-aneurysmal and systemic pressures were measured daily for 60 to 90 days after the implantation of the stent graft. Endoleak patency and flow were assessed during surgery and at the time of death by using angiographic imaging and duplex ultrasonography. Histologic analysis of the intra-aneurysmal thrombus was also performed. RESULTS: Intra-aneurysmal pressure values are indexed to systemic pressure and are represented as a percentage of the simultaneously obtained systemic pressure, which has a value of 1.0. All six animals with untreated type II endoleaks maintained patency of the endoleak and side-branch arteries throughout the study period. Compared with control aneurysms that had no endoleak, animals with patent type II endoleaks exhibited significantly higher intra-aneurysmal pressurization (systolic pressure: patent type II endoleak, 0.702 +/- 0.283; control, 0.172 +/- 0.091; P < .001; mean pressure: endoleak, 0.784 +/- 0.229; control, 0.137 +/- 0.102; P < .001; pulse pressure: endoleak, 0.406 +/- 0.248; control, 0.098 +/- 0.077; P < .001; P < .001 for comparison for all groups by analysis of variance). Treatment of the type II endoleak with polyurethane foam induced thrombosis of the endoleak and feeding side-branch arteries in all four animals with type II endoleaks. This resulted in intra-aneurysmal pressures statistically indistinguishable from the controls (systolic pressure, 0.183 +/- 0.08; mean pressure, 0.142 +/- 0.09; pulse pressure, 0.054 +/- 0.04; not significant). Angiography and histology documented persistent patency up to the time of death (mean, 64 days) for untreated type II endoleaks and confirmed thrombosis of polyurethane foam-treated endoleaks in all cases. CONCLUSIONS: Untreated type II endoleaks were associated with intra-aneurysmal pressures that were 70% to 80% of systemic pressure. Treatment with polyurethane foam resulted in a reduction of intra-aneurysmal pressure to a level that was indistinguishable from control aneurysms that had no endoleak. CLINICAL RELEVANCE: Endovascular repair of abdominal aortic aneurysms is dependent on the successful exclusion of the aneurysm from arterial circulation. Type II endoleaks originate from retrograde flow into the aneurysm sac. This study demonstrates the use of polyurethane foam to induce thrombosis in a canine model of a type II endoleak, thereby reducing intra-aneurysmal pressure to levels similar to levels in animals without endoleaks. This approach may be a strategy for future treatment of type II endoleaks.

Animals↗

PubMed2005

Branched endografts for treatment of complex aortic aneurysms.

Aortic aneurysms continue to be a major source of morbidity and mortality despite advances in operative and perioperative technology. Endovascular stent graft repair of abdominal aortic aneurysms has been widely adopted since its initial report in 1991. Improvements in device delivery systems and development of modular bifurcated stent grafts have greatly facilitated repair, and broadened the applicability of these techniques. However, aneurysmal involvement of critical branch vessels can be problematic. Experience is growing with custom-made branched endografts to maintain antegrade perfusion to critical arteries in treatment of thoracoabdominal and complex aortoiliac aneurysms. The use of branched devices allows for extension of the sealing and fixation portions of the graft into more stable aorta, while simultaneously maintaining branch vessel patency. Much remains to be learned regarding the long-term durability of these repairs; however, as additional devices are developed, it is evident that the limitations of endovascular aortic aneurysm repair will continue to diminish.

Aortic Aneurysm, Abdominal↗

PubMed2004

Endovascular aortic aneurysm repair in the octogenarian: is it worthwhile?

HYPOTHESIS: During the past decade, endovascular stent graft repair (EVSG) of abdominal aortic aneurysms has emerged as a less invasive and less morbid alternative to open surgical repair. We hypothesize that EVSG may become the treatment method of choice among patients older than 80 years. DESIGN: Retrospective case series. SETTING: Major academic medical center with extensive experience in endovascular and open aortic aneurysm surgery. PATIENTS AND METHODS: During a 5-year period, EVSG was performed in 595 patients at our institution. One hundred fifty (25.2%) of these patients were older than 80 years. Our prospectively acquired database was reviewed with respect to the demographic, intraoperative, and outcome data of this elderly population. MAIN OUTCOME MEASURES: Technical and clinical success, aneurysm-related events (aneurysm-related death, type I or type III endoleaks, aneurysm expansion, or aneurysm rupture), and secondary interventions. RESULTS: There were 119 men (79.3%) and 31 women (20.7%) (mean age, 84.6 years). Mean aneurysm diameter was 6.7 cm. Comorbidities including chronic obstructive pulmonary disease, coronary artery disease, chronic renal insufficiency, peripheral vascular disease, hypertension, and hypercholesterolemia were common in these patients, with an average of 2.9 comorbid conditions per patient. Mean follow-up was 16.9 months (range, 1.0-61.4 months). One hundred forty-six patients (97.3%) received only regional anesthesia, and the average intraoperative blood loss was 369 mL. Average hospital and intensive care unit stays were 2.5 days and 0.1 day, respectively. The procedure was performed emergently in 3 patients, and each recovered uneventfully. There were 5 aborted procedures (3.3%) for technical reasons and 4 conversions to open aortic repair (2.6%). In addition to these aborted procedures, there were 2 additional technical failures resulting in a technical success rate of 95.3%. Endoleaks were common and included 9 type I (6.90%), 35 type II (24.10%), and 1 type III (0.69%). The majority either resolved spontaneously (type IIs) or with minimally invasive secondary intervention, which was performed in 13 patients. Perioperative local/vascular and systemic complications occurred in 16 (10.7%) and 8 (5.3%) patients, respectively. There were 5 perioperative deaths (3.3%)(<30 days postoperatively). Forty late deaths (26.7%)(>30 days postoperatively) occurred, which were unrelated to the EVSG procedure. CONCLUSIONS: Endovascular repair of abdominal aortic aneurysms can be performed safely and successfully in the majority of octogenarians with relatively low complication rates. Improved EVSG devices and operator experience may make this procedure the treatment method of choice for patients in this age group who meet specific anatomical criteria.

Age Factors↗

PubMed2004

Time-resolved magnetic resonance angiography as a noninvasive method to characterize endoleaks: initial results compared with conventional angiography.

PURPOSE: Several types of endoleaks have been described, each with different methods of treatment. Conventional arteriography is widely regarded as the gold standard for the classification of endoleaks. Recently, faster magnetic resonance gradients have allowed for rapid data acquisition and review of vascular studies as a real-time continuous angiogram (time resolved magnetic resonance angiography [TR-MRA]). This study was performed to compare the findings of TR-MRA with conventional angiography for the characterization of endoleaks. METHODS: Between June 2002 and June 2003, 12 patients with documented endoleaks following endovascular repair of aortic aneurysms (10 abdominal and two thoracic) underwent TR-MRA to identify and characterize the endoleak. All patients had nitinol-based aortic stent grafts. MRA was performed on a 1.5-Tesla magnet (Sonata class; Siemens Medical Systems, Iselin, NJ). The TR-MRA studies were reviewed under continuous observation as a "cine MR angiogram." These MRA data sets were used to classify the endoleaks into types 1 through 3. The patients underwent conventional angiography following the MRA to confirm the findings and to plan treatment. The MRA findings were compared with the findings made at conventional arteriography. RESULTS: TR-MRA identified seven patients with type 1 leaks, including four proximal and three distal. Four patients had type 2 leaks, including two arising from the inferior mesenteric artery and two from an iliolumbar artery. One patient had a type 3 leak. Conventional angiography confirmed the type of endoleak in all 12 patients. CONCLUSION: These initial results demonstrate TR-MRA to be an effective noninvasive method for classifying endoleaks. This technique may allow for screening of patients with endoleaks to identify those requiring urgent repair.

Angiography, Digital Subtraction↗