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M L Marin

Publications and source records attributed to M L Marin.

At least 19 recordsLinked to original sources
PubMed2001

Relationship of the 20S proteasome and the proteasome activator PA28 to atherosclerosis and intimal hyperplasia in the human vascular system.

Down-regulation of the proteasome activator PA28 results in abnormal proteasome activation and has been implicated in the development of intimal hyperplasia (IH) in animal models. Demonstration of proteasome and PA28 expression has not yet been documented in the human vascular system. This study sought to define the distribution of the 20S proteasome and its activator PA28 in human vessels and determine the relationship between the expression of the proteasome and PA28 and the development of atherosclerosis and IH. Vascular biopsies were obtained from 70 patients at the time of surgery, were snap frozen and sectioned in 5-micron sections, and prepared using standard histological techniques. The immunoperoxidase technique was used to identify 20S proteasome and PA28 expression in diseased and normal human arteries and veins as well as in patent bypass grafts with and without IH. Expression was graded by a blinded pathologist (scale: 1-4). Repeat quantification of the immunopositive cells was also performed. Expression of 20S proteasome and PA28 was identified in all vascular tissues examined. The proteins were identified predominately within the cytoplasm of vascular smooth muscle cells and endothelial cells. PA28 was more intensely expressed in quiescent regions of the vessel wall as compared to areas undergoing active proliferation and remodeling. PA28-mediated activation of the proteasome may be necessary to maintain normal cellular homeostasis and prevent excessive cellular proliferation in the human vascular system. Abnormalities of proteasome activation may have a significant role in the development of atherosclerosis and IH.

Aged↗
PubMed2001

Immune responses to multiple antigen peptides containing T and B epitopes from Plasmodium falciparum circumsporozoite protein of Brazilian individuals naturally exposed to malaria.

We have evaluated the immune responses of individuals living in a malaria endemic area of Brazil to the (T1B)4, a multiple antigen peptide (MAP) from Plasmodium falciparum circumsporozoite (CS) protein and the related monoepitope MAPs, B4 and (T1)4, and the linear peptides, T1B and B. The highest antibody frequencies were against MAPs containing the B cell epitope sequence (T1B)4 (42.2%) and B4 (28.8%), while the highest lymphoproliferative response frequencies were against the MAPs containing the T cell epitope sequence (T1)4 (47%) and (T1B)4 (36.4%). We analysed individual responses considering lymphoproliferative response to (T1)4 MAP and IgG antibody titre to (T1B)4 as patterns of ideal cellular and humoral responses, respectively. The frequency of responders, cellular and/or humoral was 66.6%, significantly higher than non responders (P = 0.003). We also determined the HLA class II haplotype of each individual but no association between these and immune response patterns to the MAPs was observed. The results showed that individuals primed against P. falciparum in their natural habitat, present a very diverse array of responses against the same peptide antigens, varying from no response in one-third of the individuals to cognate B and T cell responses. Our study underlines the importance of previous studies of vaccine candidates to guarantee that the immunization will be capable of reverting inefficient or absent responses to malaria epitopes.

Animals↗
PubMed2001

Endovascular stent grafting in the presence of aortic neck filling defects: early clinical experience.

OBJECTIVE: Although endovascular grafts have been increasingly applied to the treatment of abdominal aortic aneurysms, their use in clinical trials is limited by well-defined anatomical exclusion criteria. One such criterion is the presence of thrombus within the infrarenal neck of an aneurysm, which is thought to (1) prevent the creation of a permanent watertight seal between the graft and the vessel wall, resulting in an endoleak; (2) contribute to stent migration; and (3) increase the risk of thromboembolism. This article summarizes our experience with endovascular abdominal aortic aneurysm exclusion in 19 patients with large aortic aneurysms, significant medical comorbidities, and apparent thrombus extending into the pararenal aortic neck. METHODS: Of 268 patients undergoing abdominal aortic aneurysm repair, 19 (7%; 17 men; mean age, 71 years) demonstrated computed tomographic and angiographic evidence of intramural filling defects at the level of the aortic neck. In no instance did these filling defects extend above the renal arteries. Endovascular grafting was performed through use of a balloon-expandable Palmaz stent and an expanded polytetrafluoroethylene graft, delivered and deployed under fluoroscopic guidance. Follow-up at 3, 6, and 12 months and annually thereafter was performed with computed tomography and duplex ultrasound scan. RESULTS: Spiral computed tomography and aortography revealed an irregular flow-limiting defect, occupying up to 75% of the aortic circumference, in every case. The mean aneurysm size, aortic neck diameter, and neck length before the procedure were 6.1, 2.43, and 1.4 cm, respectively; the mean aortic neck diameter after the procedure was 2.61 cm. No primary endoleaks were observed after graft insertion, and no delayed endoleaks have been detected during follow-up, which ranged from 7 to 48 months (mean, 23 months). In one patient, an asymptomatic renal artery embolus was detected on immediate follow-up computed tomography, and in another patient, an asymptomatic posterior tibial embolus occurred. CONCLUSION: No primary endoleaks, endograft migration, or significant distal embolization were observed after endografting in patients with aortic neck thrombus. The deployment of the fenestrated portion of the stent, above the thrombus and across the renal arteries, allows for effective renal perfusion, graft fixation, and exclusion of potential mural thrombus from the circulation. The presence of aortic neck thrombus may not necessarily be a contraindication to endovascular repair in select patients.

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PubMed2001

Histopathologic analysis of endovascular stent grafts from patients with aortic aneurysms: Does healing occur?

BACKGROUND: Research with animal models has demonstrated tissue healing of endovascular grafts in both native arterial segments and in experimentally created arterial aneurysms. Fundamental to the successful clinical use of endovascular grafts for the treatment of aneurysmal disease is the creation of a permanent hemostatic seal between the graft ends and the arterial wall. Characteristics of this healing process in patients with aneurysmal disease have not been fully studied. In this study, we analyzed the macroscopic and histopathologic changes of the arterial wall after endovascular repair of aortic aneurysms. METHODS: Over a 7-year period, 313 patients were treated with endovascular grafts to exclude arterial aneurysms of the thoracic and abdominal aorta. Of these patients, 11 had their endovascular grafts recovered for analysis. Five graft specimens were recovered during subsequent open aortic surgery. Six grafts were recovered at autopsy after the death of the patient of causes unrelated to the patient's endovascular graft. All specimens were fixed in formalin. Histologic analysis included light microscopy with hematoxylin and eosin and trichrome stains. Well-preserved specimens were selected after light microscopic examination and postfixed in 3% buffered glutaraldehyde for electron microscopy. The aortas from autopsy specimens were removed en bloc and fixed in formalin; representative regions of each graft were sectioned for analysis. Adherence of the graft to the vessel wall was categorized as densely adherent or easily separated after graft explantation. Traction applied to the graft-aortic anastomosis was equal to traction generated by suspending a standardized 2-kg weight. Infrarenal graft specimens were obtained with supraceliac aortic clamping, longitudinal aortotomy, and graft sampling before endograft revision. RESULTS: In eight patients, endograft fixation was found to be firmly adherent to the arterial wall. A translucent film of fibrinous material was consistently seen across the entire luminal surface of the endograft. Light and electron microscopy failed to demonstrate an endothelial layer or organized pseudointima at the graft-artery interface. CONCLUSION: Despite suggestive experimental data regarding endograft healing in animals, minimal graft incorporation was apparent in the stent grafts recovered in this study. A greater emphasis on the construction and mechanism of fixation of endograft attachment systems will be important for long-term device function.

Aged↗
PubMed2001

Endovascular repair of para-anastomotic aneurysms of the aorta and iliac arteries: preferred treatment for a complex problem.

PURPOSE: Standard surgical repair of para-anastamotic aneurysms (PAAs) of the abdominal and thoracic aorta and the iliac arteries has been associated with high morbidity and mortality rates. We reviewed our continuing experience with endovascular repair of these lesions to determine whether this approach is favorable and durable. METHODS: All patients with PAAs of the aorta or iliac arteries who underwent endovascular treatment of their lesions between August 1993 and July 1999 were prospectively followed up, and data on age, previous aortic pathology and surgery, size of PAA, time to diagnosis, and symptoms at presentation were recorded. Preoperative, intraoperative, and postoperative imaging studies were analyzed. All patients had endovascular stent-grafts placed under digital fluoroscopic guidance in the operating room. Data on intraoperative and postoperative complications, mortality, and endoleaks were reviewed. RESULTS: From August 1993 to July 1999, 28 patients (20 men, 8 women) had 35 PAAs of the aorta or iliac arteries. There were 5 thoracic aortic, 12 abdominal aortic, and 18 iliac artery PAAs. Three patients had a contained rupture of their PAA. All patients who had originally undergone reconstruction for occlusive disease had lesions consistent with false aneurysms, whereas 73% of the aortic or iliac PAAs in patients originally treated for aneurysm disease appeared to be true aneurysms. Thirty-four of 35 PAAs were successfully excluded with stent-grafts (97%). There was one death at 30 days (3.6%) in a patient who was successfully treated endovascularly for a contained rupture of a thoracic PAA. There were four major postoperative complications (14.2%) in the 28 patients who were treated. One patient had continued perfusion of a thoracic aortic PAA (type I endoleak). The in-hospital length of stay after endovascular repair of PAA was 4 days (range, 1-18 days). The mean follow-up period was 21 months (range, 1-68 months). CONCLUSION: Endovascular repair of aortic and iliac artery PAAs is technically feasible and provides a high rate of lesion exclusion. Morbidity and mortality rates appear lower than those reported for open surgical repair. These patients can typically be discharged by the second postoperative day. Endovascular therapy for stable ruptured PAAs can be successfully performed and should be considered as an option only when appropriate devices and expertise are available. For uncomplicated PAAs of the aorta and iliac arteries, endovascular therapy may be more favorable than surgical repair.

Adult↗
PubMed2001

Intentional internal iliac artery occlusion to facilitate endovascular repair of aortoiliac aneurysms.

PURPOSE: The safety of intentional occlusion of patent internal iliac arteries (IIAs) to facilitate the endovascular repair of aortoiliac artery aneurysms (abdominal aortic aneurysms [AAAs] and iliac aneurysms [IAs]) was evaluated. METHODS: We analyzed the techniques and clinical sequelae of selective occlusion of one or both IIAs in 103 patients and correlated these findings with the results of preoperative angiograms to identify vascular anatomy that may predict postoperative pelvic ischemia. To quantify the clinical presentation of pelvic ischemia, we developed these criteria: class 0, no symptoms; class I, nonlimiting claudication with exercise; class II, new onset impotence, with or without moderate to severe buttock pain, leading to physical limitation with exercise; class III, buttock rest pain, colonic ischemia, or both. IIA occlusion was achieved in 100% of the patients by means of either catheter-directed embolization or orificial coverage with a stent-graft. No patient in this study had angiographic evidence of significant visceral occlusive disease before the procedure. Sixty-four patients had isolated AAAs, 23 patients had AAAs and IAs, and 16 patients had isolated IAs. Ninety-two patients had one IIA selectively occluded, and 11 patients had both IIAs selectively occluded. RESULTS: After IIA occlusion, 12 patients were categorized in class I, 9 patients were categorized in class II, and 1 patient was categorized in class III, for a total of 22 patients (21%) with pelvic ischemia. Sixteen (17%) of 92 patients had unilateral IIA occlusions, and six (17%) of 11 patients had bilateral IIA occlusions. Five patients in class I improved and had no symptoms within 1 year, and one patient in class II was downgraded to class I because of improved symptoms. Two unique preoperative angiographic findings were identified in the remaining 16 patients (16%) with chronic pelvic claudication: (1) stenosis of the remaining IIA origin (> 70%) with nonopacification of more than three of the six IIA branches (63%); and (2) small caliber, diseased or absent medial and lateral femoral circumflex arteries ipsilateral to the side of the IIA occlusion (25%). One patient with class III ischemia died of cardiovascular collapse associated with colon infarction caused by either acute ischemia or particulate embolization. CONCLUSION: The incidence of pelvic ischemia after IIA occlusion is 20% immediately after endovascular aortoiliac aneurysm repair. A total of 25% of patients had no symptoms within 1 year. Two preoperative radiologic findings may help identify patients who are at risk for pelvic ischemia: stenosis of the patent IIA and disease deep femoral ascending branches ipsilateral to the occluded IIA. The risk of colon ischemia appears to be small after selective IIA occlusion to facilitate endovascular AAA repair.

Aged↗
PubMed2001

Ancillary techniques to facilitate endovascular repair of aortic aneurysms.

PURPOSE: The ability to treat abdominal aortoiliac aneurysms and thoracic aortic aneurysms may be limited by coexisting arterial disease. Device deployment may be impaired by occlusive disease and tortuosity of the arteries used to access the aneurysm or by suitability of the implantation sites. In this study we describe the auxiliary procedures performed to circumvent these obstacles and thereby enable endovascular aneurysm repair. PATIENTS AND METHODS: Between January 1, 1993, and December 31, 1999, 390 patients treated for aneurysm of the aorta with endovascular devices were entered prospectively in a vascular registry. Fifty (12%) of the 390 patients required adjunctive surgical techniques to (1) create or extend the length of the proximal or distal device implantation site or (2) permit device navigation through diseased iliac arteries. Auxiliary techniques used to extend or enhance implantation sites were elephant trunk graft (n = 2), the construction of renovisceral bypass grafts (n = 1), and subclavian artery transposition (n = 2). Plication of the common iliac artery at its bifurcation was performed in conjunction with femorofemoral bypass graft in nine patients to allow preservation of pelvic circulation by avoiding internal iliac artery sacrifice. Construction of a bypass graft to transpose the internal iliac artery orifice was performed in one patient. The auxiliary techniques used to facilitate device navigation were iliac artery angioplasty or stenting (n = 8), external iliac artery endovascular endarterectomy or straightening (n = 14), endoluminal iliofemoral bypass conduit (n = 5), and the construction of an open iliofemoral bypass conduit (n = 8). RESULTS: Successful deployment of the endovascular devices was achieved in 49 (98%) of 50 patients. Auxiliary techniques were successful in providing access for endovascular device deployment in all 35 patients (100%). Mean follow-up for techniques to facilitate device navigation is 26 months for endovascular procedures and 42 months for the open bypass graft construction patients; no occlusions were observed at this moment. There were five patients with incisional hematomas that did not necessitate intervention. Fourteen (94%) of 15 patients underwent successful device implantation after the auxiliary maneuvers to enhance implantation site. Mean follow-up for implantation site manipulation is 28 months. One of the subclavian transpositions had a new onset of Horner's syndrome, two of nine patients who had common iliac artery ligated had retroperitoneal hematomas that did not necessitate interventions, and no colon ischemia was seen. The patient who underwent nonanatomic bypass grafting of viscero-renal arteries had a retroperitoneal hematoma that necessitated reexploration. CONCLUSIONS: Significant coexisting arterial disease may be encountered in patients with aortic or iliac aneurysms. Identification of coexisting arterial diseases is essential to help tailor the appropriate supplemental surgical procedure to allow the performance of endovascular aneurysm repair in patients who would otherwise require open surgical repair.

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PubMed2001

Internal iliac artery revascularization as an adjunct to endovascular repair of aortoiliac aneurysms.

PURPOSE: Endovascular repair of aortoiliac aneurysms may be limited by extension of the aneurysm to the iliac bifurcation, necessitating endpoint implantation in the external iliac artery. In such cases the circulation to the internal iliac artery is interrupted. Bilateral internal iliac artery occlusion during endovascular repair may be associated with significant morbidity, including gluteal claudication, erectile dysfunction, and ischemia of the sigmoid colon and perineum. We have employed internal iliac artery revascularization (IIR) to allow endograft implantation in the external iliac artery while preserving flow to the internal iliac artery in patients with aneurysms involving the iliac bifurcation bilaterally. METHODS: A total of 11 IIR procedures were performed in 10 patients undergoing endovascular abdominal aortic aneurysm (AAA) repair (9 men, 1 woman; mean age, 74 years). IIR was accomplished via a retroinguinal incision in 9 cases and a retroperitoneal incision in 2 cases. Six-mm polyester grafts were used for external-to-internal iliac artery bypass in 10 cases and internal iliac artery transposition onto the external iliac artery was used in one case. Endovascular AAA repair was performed using a modular bifurcated device (Talent-LPS, Medtronics, Minneapolis, Minn) after IIR. Bypass graft patency was determined immediately after the surgery, at 1 month, and every 3 months thereafter, using duplex ultrasound scanning and computed-tomography angiography. Mean aneurysm diameters were as follows: AAA, 6.4 +/- 0.7 cm; ipsilateral common iliac, 3.7 +/- 1.0 cm; contralateral common iliac, 3.9 +/- 0.8 cm. RESULTS: Successful IIR and endovascular AAA repair were accomplished in all cases. No proximal, distal, or graft junction endoleaks occurred. Two patients demonstrated retrograde aneurysm side-branch endoleaks originating from the lumbar arteries. One thrombosed spontaneously within 3 months. One perioperative myocardial infarction occurred. Reduction in aneurysm size was documented in 5 aortic, 5 ipsilateral iliac, and 3 contralateral iliac aneurysms. Gluteal claudication, erectile dysfunction, colon and perineal ischemia, and mortality did not occur. All IIRs have remained patent during a follow-up period of 4 to 15 months (mean, 10.1 months). CONCLUSIONS: IIR may be used with good short-term to intermediate-term patency to prevent pelvic ischemia in patients whose aneurysm anatomy requires extension of the endograft into the external iliac artery. This may allow endovascular AAA repair to be performed in patients who might otherwise be at risk for developing complications associated with bilateral internal iliac artery occlusion.

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PubMed2001

Endovascular repair of bleeding aortoenteric fistulas: a 5-year experience.

PURPOSE: Aortoenteric fistula (AEF) is an uncommon but catastrophic complication that can occur either primarily or after aortic reconstruction. Untreated, it is uniformly fatal. Conventional surgical management is associated with a perioperative mortality rate of 25% to 90% and frequent major complications. We reviewed our experience with the endovascular treatment of both primary and secondary AEFs in an effort to determine whether endovascular repair is a less morbid alternative to traditional surgical treatment in select patients. METHODS: In a 5-year period, seven high-risk patients who had bleeding and an AEF documented by means of radiology or endoscopy (2 primary, 5 secondary) were treated with coil embolization (1) or placement of an endovascular aortic stent graft (3 aortouniiliac, 2 tube, 1 bifurcated). One patient underwent computed tomography (CT)-guided percutaneous catheter drainage of an infected perigraft collection. The average follow-up period was 27 months (range, 11-66 months), and follow-up consisted of physical examination, complete blood count, and contrast-enhanced helical CT scanning at 3, 6, and 12 months and yearly thereafter. All patients were treated with intravenous antibiotics perioperatively and were prescribed life-long oral antibiotics on discharge. RESULTS: There was one perioperative death (14%) caused by fungal sepsis. Persistent sepsis after stent-graft placement necessitated laparotomy and bowel resection in one patient. One patient had three bouts of recurrent sepsis that were successfully treated with a change of antibiotic. There were three late deaths (43%) unrelated to the procedure or AEF. Three patients (43%) were alive and well an average of 36 months (range, 23-67 months) after the procedure, with no clinical or radiologic evidence of recurrent bleeding or infection. CONCLUSION: Endovascular management of AEFs is technically feasible and may be the preferred treatment in select patients with bleeding and no signs of sepsis. In the setting of gross infection, it may also be considered in high-risk patients as a bridge to more definitive treatment after hemodynamic stabilization and optimization.

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PubMed2001

Risk of spinal cord ischemia after endograft repair of thoracic aortic aneurysms.

BACKGROUND: Surgical repair of thoracoabdominal aneurysms may be associated with a significant risk of perioperative morbidity including spinal cord ischemia, which occurs at a rate of between 5% and 21%. Spinal cord ischemia after endovascular repair of thoracic aortic aneurysms (TAAs) has also been reported. This investigation reviews the occurrence of spinal cord ischemia after endovascular repair of descending TAAs at the Mount Sinai Medical Center. PATIENTS AND METHODS: Between May 1997 and April 2001, 53 patients underwent endovascular exclusion of their TAA. Preprocedure computed tomography scanning and angiography were performed on all patients. All were performed in the operating room using C-arm fluoroscopy. Physical examinations and computed tomography scans were performed at discharge and at 1, 3, 6, and 12 months postoperatively and then annually thereafter. Spinal cord ischemia developed in three of the 53 patients (5.7%) postoperatively. In one patient, cord ischemia developed that manifested as early postoperative left leg weakness occurring after concomitant open infrarenal abdominal and endovascular TAA repair. The neurologic deficit resolved 12 hours after spinal drainage, steroid bolus, and the maintenance of hemodynamic stability. The remaining two patients developed delayed onset paralysis, one patient on the second postoperative day and the other patient 1 month postrepair. Both of these patients had previous abdominal aortic aneurysm repair, and both required long grafts to exclude an extensive area of their thoracic aortas. Irreversible cord ischemia and paralysis occurred in both of these patients. CONCLUSIONS: Endovascular repair of TAA has shown a promising reduction in operative morbidity; however, the risk of spinal cord ischemia remains. Concomitant or previous abdominal aortic aneurysm repair and long segment thoracic aortic exclusion appear to be important risk factors. Spinal cord protective measures (ie, cerebrospinal fluid drainage, steroids, prevention of hypotension) should be used for patients with the aforementioned risk factors undergoing endovascular TAA repair.

Aged↗
PubMed2001

Current use of endovascular grafts for the treatment of abdominal aortic aneurysms.

The development of endovascular techniques for the treatment of abdominal aortic aneurysms has significantly reduced the major morbidity associated with standard surgical repair. The indications for use of endovascular grafts and the limitations of their use have not been fully defined. The effectiveness of the numerous commercially fabricated devices is currently being evaluated. This article describes the general principles of use for endovascular devices and details the features and results for the devices in current use.

Aortic Aneurysm, Abdominal↗
PubMed2000

Endovascular grafts in the treatment of thoracic aortic aneurysms and pseudoaneurysms.

The purpose of this study was to describe our experience with balloon and self-expanding endovascular grafts for the management of thoracic aortic lesions. Between February 1997 and June 1998, 20 endovascular grafts were implanted in 14 patients for the treatment of thoracic aortic aneurysms and pseudoaneurysms. Endovascular procedures were performed using one of four different devices: (1) Dacron-covered balloon-expandable Palmaztrade mark stent, (2) balloon-expandable Palmaz stent-PTFE graft prosthesis (BE-PS), (3) self-expanding internally supported Nitinol Dacron prosthesis (Vanguardtrade mark SE-V), and (4) self-expanding externally supported Nitinol PTFE prosthesis (Excludertrade mark SE-E). The results show that endovascular grafting represents a potentially important alternative therapy to open repair of the thoracic aorta. Self-expanding devices were, in our experience, easier to use and more accurately deployed.

Adult↗
PubMed2000

The value of the oblique groin incision for femoral artery access during endovascular procedures.

Groin incisions for access to femoral vessels are typically made in a vertical fashion extending across the groin crease. Significant morbidity can be associated with these incisions, including lymphoceles, lymph fistulae and infections, as documented in the infrainguinal revascularization literature. We have adopted an oblique groin incision for femoral artery access during endovascular graft reconstruction of the aorta because of the potential for reduced wound morbidity. In this study we report our experience with this technique and compare it with the existing literature to determine its usefulness. From June 1998 to May 1999, 98 consecutive patients received endovascular exclusion of aortic aneurysms at The Mount Sinai Medical Center, New York. Patients were treated with aortoaortic (24), aortouniiliac with femorofemoral crossover bypass (41), or bifurcated endografts (33) and were prospectively studied for wound complications. Aortoaortic procedures required one inguinal incision whereas aortouniiliac with femorofemoral crossover bypass and bifurcated procedures employed bilateral inguinal wounds. Wound complications were defined as cellulitis, subcutaneous purulence, femorofemoral graft infection, lymphocele, or lymphocutaneous fistulae. The oblique groin incision allows adequate exposure to the femoral arteries and is associated with low wound morbidity. We suggest that this approach may be the preferred technique for access to femoral arteries during endovascular procedures, and should be considered for infrainguinal arterial reconstructions.

Aged↗
PubMed2000

Alternative techniques for management of distal anastomoses of aortofemoral and iliofemoral endovascular grafts.

PURPOSE: Techniques for managing the distal anastomoses of aortofemoral and iliofemoral endovascular grafts are described. METHODS: Over a 2(1/2)-year period 46 endovascular grafts were successfully placed to treat severe iliac artery occlusive disease. Endovascular grafts were anchored proximally in the distal aorta or iliac arteries with Palmaz balloon-expandable stents. The distal anastomoses were performed with the use of open, sutured anastomotic techniques. In contrast to stented distal anastomoses, these techniques allowed us to (1) treat occlusive lesions extending from the distal aorta to below the inguinal ligament, (2) terminate endovascular grafts in the groin where stents are contraindicated, (3) vary the distal anastomotic site depending on the local pattern of disease, and (4) standardize the preinsertion length of the endovascular graft. RESULTS: Two distal perianastomotic stenoses and one graft occlusion were detected postoperatively in 11 bypass grafts that had distal anastomoses sewn endoluminally without an overlying patch angioplasty. Only one perianastomotic stenosis was found among 35 anastomoses performed with other techniques. There were no significant differences in primary and secondary patency between grafts originating in the distal aorta or iliac arteries. CONCLUSIONS: Hand-sewn distal anastomoses can simplify the insertion of endovascular grafts used for the treatment of aortoiliac occlusive disease. These anastomoses permit tailoring of the graft according to the patients' pattern of disease and eliminate the need to precisely measure the length of the graft preoperatively. In addition, because a distal stent is not required, endovascular grafts can be safely terminated in the groin instead of the external iliac artery where disease progression can lead to graft failure. Finally, endovascular distal anastomoses should be closed with a patch or the hood of a more distal bypass graft to prevent perianastomotic stenoses or occlusions in the postoperative period.

Adult↗
PubMed2000

Safety and efficacy of high-dose adenosine-induced asystole during endovascular AAA repair.

PURPOSE: To assess the safety and efficacy of high-dose adenosine administration to increase the precision of endovascular abdominal aortic aneurysm (AAA) repair using a balloon deployed stent-graft. METHODS: From January 1997 to March 1999, 98 AAA patients (79 men; mean age 71 years, range 62-91) were treated with balloon-expandable stent-grafts under an approved protocol. After placing a temporary transvenous ventricular lead or an external transthoracic pacing electrode, adenosine (24 mg initially) was administered in an escalating dose fashion to induce at least 10 seconds of asystole, during which the proximal stent was expanded. RESULTS: Adenosine dosages ranged from 24 to 90 mg (median 24 mg). Nine (9.2%) self-limiting cardiac events were observed: 2 (2.0%) episodes of transient myocardial ischemia, 2 (2.0%) cases of atrial fibrillation requiring cardioversion, 1 (1.0%) transient left bundle branch block lasting <10 seconds, and 4 (4.1%) prolonged periods of asystole requiring temporary pacemaker activation. There were no cases of bronchospasm or worsening obstructive pulmonary disease, and no patients required inotropic support after adenosine-induced asystole. CONCLUSIONS: Cardiac events following adenosine-induced asystole are infrequent, mild, and easily treated. The perioperative use of high-dose adenosine to ensure precise stent-graft placement appears to be a safe method of inducing temporary asystole during endovascular aortic repair.

Adenosine↗
PubMed2000

A laser flash photolysis and pulse radiolysis study of primary photochemical processes of flumequine.

The 355 nm laser flash photolysis of argon-saturated pH 8 phosphate buffer solutions of the fluoroquinolone antibiotic flumequine produces a transient triplet state with a maximum absorbance at 575 nm where the molar absorptivity is 14,000 M(-1) cm(-1). The quantum yield of triplet formation is 0.9. The transient triplet state is quenched by various Type-1 photodynamic substrates such as tryptophan (TrpH), tyrosine, N-acetylcysteine and 2-deoxyguanosine leading to the formation of the semireduced flumequine species. This semireduced form has been readily identified by pulse radiolysis of argon-saturated pH 8 buffered aqueous solutions by reaction of the hydrated electrons and the CO2*- radicals with flumequine. The absorption maximum of the transient semireduced species is found at 570 nm with a molar absorptivity of 2,500 M(-1) cm(-1). In argon-saturated buffered solutions, the semireduced flumequine species formed by the reaction of the flumequine triplet with TrpH stoichiometrically reduces ferricytochrome C (Cyt Fe3+) under steady state irradiation with ultraviolet-A light. In the presence of oxygen, O2*- is formed but the photoreduction of Cyt Fe3+ by O2*- competes with an oxidizing pathway which involves photo-oxidation products of TrpH.

Anti-Infective Agents↗
PubMed1999

Intraoperative rupture of an abdominal aortic aneurysm during an endovascular stent-graft procedure.

PURPOSE: To highlight the risk of intraoperative rupture as a complication of endovascular aortic repair. CLINICAL FEATURES: An 81-yr-old man was admitted for endovascular aortic repair of a 6 cm infrarenal abdominal aortic aneurysm. After establishment of a conduction blockade using a combined spinal-epidural technique, a balloon-activated endovascular stent-graft was advanced to the proximal aneurysmal neck. Approximately four minutes after the stent-graft was deployed, the mean arterial pressure decreased to 30 mmHg and the heart rate increased to 135 bpm. While fluid and vasoactive medications were administered and the airway was secured, repeat aortography confirmed contrast extravasation into the retroperitoneal space at the junction of the proximal aortic neck and the aneurysm sac. The angioplasty deployment balloon was repositioned and inflated proximal to the presumed site of aortic rupture, thus providing aortic control until an open repair of the aorta was undertaken. CONCLUSION: Although endovascular stent-graft placement may be a less invasive method than conventional open aortic reconstruction, it must be recognized that the potential for devastating consequences such as aortic rupture is present.

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