Biomedical subjects

M L Marin

Publications and source records attributed to M L Marin.

At least 37 records · Page 2Linked to original sources

PubMed1999

Experience with endovascular grafts in the treatment of infrarenal aortic aneurysms associated with proximal aortic dissection.

BACKGROUND: Chronic abdominal and thoracic aortic dissections often present with concomitant infrarenal aortic dilatation. We conducted a retrospective review of 6 patients treated with endovascular stent grafts for coexisting aortic dissection and infrarenal aneurysm. METHODS: Six patients with suprarenal aortic dissections and infrarenal aortic aneurysms (AAA) had their AAAs treated with endovascular grafts. Grafts were constructed of balloon expandable Palmaz stents and expanded polytetrafluoroethylene graft. The device was inserted transfemorally and deployed under fluoroscopy. RESULTS: Successfully primary AAA exclusion was achieved in 5 patients. One patient required a supplemental stent placed above the endograft and into the true lumen to seal the endoleak. No aneurysm has enlarged, and all remain thrombosed for 9 to 24 months (mean 20). One type III dissection enlarged 2 weeks after endograft insertion. One patient had uncomplicated cephalad fenestration of a dissection by the endograft. CONCLUSIONS: Endovascular grafts may be used to treat coexisting AAA and aortic dissection. Attention to the site or sites of reentry of a dissection is essential to insure full aortic aneurysm exclusion. The fate of a chronic aortic dissection cephalad to an endovascularly treated AAA is unclear and will require longer follow-up.

Aortic Dissection↗

PubMed1999

Stent grafts in occlusive arterial disease.

The use of endovascular grafts for the treatment of occlusive arterial disease continues to evolve as the sophistication of currently available devices improves with regard to device composition and delivery systems. Endovascular grafting for occlusive arterial disease is particularly useful in high-risk patients with medical comorbidities who are otherwise unfit for a major operation and conventional open repair. The early term and midterm results on the treatment of occlusive, iliac, and femoropopliteal disease have been encouraging. Further refinements in catheter technology, stent grafts, and delivery systems will further extend the use of these devices. Increasing experience from centers using different devices and long-term follow-up with regard to durability and complication will establish the role of endovascular grafts as alternatives to conventional repair.

Aorta↗

PubMed1999

Midterm results of endovascular stented grafts for the treatment of isolated iliac artery aneurysms.

PURPOSE: Isolated aneurysms of the iliac arteries are uncommon lesions that require surgical repair to prevent rupture. METHODS: During a 4-year period, we used endovascular stented grafts (EGs) to treat 28 iliac artery aneurysms that were not associated with aortic aneurysms. Twenty-five patients, with a total of 24 common iliac (15 right, nine left) and four internal iliac (two right, two left) artery aneurysms, underwent endovascular grafting. There were 24 men and 1 woman, with a mean age of 74 years (range, 51 to 88 years). Combined common and internal iliac artery aneurysms were present in three patients. Nineteen patients who underwent treatment with EGs were administered epidural anesthesia (22 epidural, two local, one general). Before surgery, one patient had lower extremity embolization and ischemia from the aneurysm, three had abdominal or back pain, and the remaining were asymptomatic. The EGs were constructed of polytetrafluoroethylene grafts and balloon expandable stents. RESULTS: Four procedure-related complications (12%) occurred (distal extremity embolization, n = 1; wound complications, n = 2; colonic mucosal ischemia, n = 1). Only a minimal reduction in the aneurysmal diameter was seen in 90% of the iliac artery aneurysms treated. The remaining lesions showed no change in size, and no aneurysm had an increase in cross-sectional diameter on computed tomographic images enduring a follow-up period up to 4 years (mean, 24 months). One aneurysm ruptured after successful endovascular exclusion, and the patient underwent treatment with open repair. The 3-year primary patency rate of iliac EGs was 86%. CONCLUSION: EGs appear to show satisfactory safety and efficacy for the repair of isolated aneurysms of the iliac arteries.

Aged↗

PubMed1999

Endovascular repair of abdominal aortic aneurysms in patients with congenital renal vascular anomalies.

PURPOSE: The endovascular repair of abdominal aortic aneurysms (AAAs) has been suggested as an alternative to conventional aortic reconstruction. The presence of anomalous renal vascular anatomy frequently necessitates special planning during conventional aortic replacement and may also create unique challenges for endovascular repair. We analyzed our experience with 24 patients with variant renal vascular anatomies who underwent treatment with aortic endografts to determine the safety and efficacy of this technique in this population. METHODS: During a 6-year period, 204 patients underwent aortic endograft procedures, 24 (11.8%) of whom had variations in renal vascular anatomy. There were 19 men and five women. Each of the 24 patients had variant renal vascular anatomy, which was defined by the presence of multiple renal arteries (n = 32), with or without a renal parenchymal anomaly (horseshoe or solitary pelvic kidney). Twenty patients underwent aneurysm repair with balloon expandable polytetrafluoroethylene grafts, and the remaining patients underwent endograft placement with self-expanding attachment systems. Eighteen patients underwent exclusion and presumed thrombosis of anomalous renal branches to effectively attach the aortic endograft. The decision to sacrifice a supernumerary artery was made on the basis of the vessel size (<3 mm), the absence of coexisting renal insufficiency, and the expectation for successful aneurysm exclusion. RESULTS: The successful exclusion of the AAAs was achieved in all the patients, with the loss of a total of 17 renal artery branches in 12 patients. Small segmental renal infarcts (<20%) were detected in only six of the 12 patients with follow-up computed tomographic scan results, despite angiographic evidence of vessel occlusion at the time of endografting. No evidence of new onset hypertension or changes in antihypertensive medication was seen in this group. No retrograde endoleaks were detected through the excluded renal branches on late follow-up computed tomographic scans. Serum creatinine levels before and after endografting were unchanged after the exclusion of the AAA in all but one patient with multiple renal branches. One patient had a transient rise in serum creatinine level presumed to be caused by contrast nephropathy. CONCLUSION: On the basis of this experience, we recommend the consideration of endovascular grafting for patients with AAAs and anomalous renal vessels when the main renal vascular anatomy can be preserved and when the loss of only small branches (<3 mm) is necessitated in patients with otherwise normal renal functions.

Aged↗

PubMed1999

Posterior approach to the deep femoral artery.

Unusual surgical approaches to the deep femoral artery are valuable when the standard anterior approach is difficult because of scarring or infection. A posterior approach to the deep femoral artery in patients, in whom all other approaches were unsuitable, is described.

Aged↗

PubMed1999

Endovascular aortic repair is associated with greater hemodynamic stability compared with open aortic reconstruction.

OBJECTIVE: Examination of overall hemodynamic stability in patients undergoing endovascular aortic repair (EAR) compared with open aortic repair (OAR). DESIGN: Retrospective study. SETTING: University hospital setting. PARTICIPANTS: Seventy-two patients undergoing OAR and 17 patients undergoing EAR were studied. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Physiologic parameters were extracted every 15 seconds from computerized anesthesia records. Median values were calculated for every 2-minute epoch, and the absolute value of the fractional change in median (|FCM|) from epoch to epoch was calculated for a maximum of 5 hours during the intraoperative period. The incidence of extremes in hemodynamic parameters was compared. Data are presented as median and interquartile ranges. The frequency of |FCM| greater than 0.06 for mean arterial pressure (MAP) was significantly greater in the OAR compared with the EAR group (0.37 [0.30, 0.46] vs 0.14 [0.11, 0.21], p < 0.0001), implying greater stability in MAP during EAR. Similarly, the mean pulmonary artery pressures (MPAPs) were significantly more stable during EAR compared with OAR (frequency of |FCM| > 0.07: EAR, 0.20 [0.16, 0.27] vs OAR, 0.32 [0.26, 0.391; p < 0.01). No intergroup differences were detected in heart rate (HR), systolic (SPAP) or diastolic pulmonary artery pressures (DPAP), or central venous pressures (CVPs). With the exception of a greater incidence of low CVP during EAR, there were no significant differences in the frequency of extremes of hemodynamic values between groups. CONCLUSION: These results show improved hemodynamic stability during EAR compared with OAR.

Aged↗

PubMed1999

Intraoperative transoesophageal echocardiography as an adjuvant to fluoroscopy during endovascular thoracic aortic repair.

OBJECTIVES: To define the utility of intraoperative transeophageal echocardiography (TEE) during endovascular thoracic aortic repair. DESIGN: Retrospective study. MATERIALS: Five patients underwent six transluminal endovascular stent-graft procedures for repair of thoracic aortic disease. METHODS: After induction of anaesthesia, a multiplane or biplane TEE probe was placed to obtain views of the diseased aorta. Both transverse and longitudinal planes of the aortic arch and descending thoracic aortic segments were imaged. The aortic pathology was confirmed by TEE and the proximal and distal extents of the intrathoracic lesion were defined. Doppler and colour-flow imaging was used to identify flow patterns through the aorta before and after stent-graft deployment. RESULTS: Visualisation and confirmation of the aortic pathology by ultrasonography was accomplished in all patients. TEE was able to confirm proper placement of the endograft relative to the aortic lesion after deployment and was able to confirm exclusion of blood flow into the aneurysm sacs. CONCLUSIONS: TEE may facilitate repair by confirming aortic pathology, identifying endograft placement, assessment of the adequacy of aneurysm sack isolation, as well as dynamic intraoperative cardiac assessment.

Adult↗

PubMed1999

Analysis of endovascular graft treatment for aortoiliac occlusive disease: what is its role based on midterm results?

OBJECTIVE: To analyze the authors' midterm results (up to 4 years) using endovascular grafts to treat aortoiliac occlusive disease in patients with limb-threatening ischemia. SUMMARY BACKGROUND DATA: Endovascular grafts are being used to manage some aortoiliac lesions formerly treated by aortofemoral or extraanatomic bypass grafts. However, widespread acceptance of these new grafts depends on their late patency and clinical utility. METHODS: Between January 1993 and December 1997, 52 patients with aortoiliac occlusive disease were treated with endovascular grafts. The primary indication for treatment was gangrene or ulceration in 42 patients (81%) and rest pain in 10 patients (19%). Sixteen patients had symptomatic contralateral limbs that were also treated, and 27 (52%) patients required a synchronous infrainguinal bypass. Results up to 4 years were evaluated by life table analysis. RESULTS: Forty-six (88%) of the patients had complete follow-up of 3 to 57 months (median 22 months). Six patients were lost to follow-up at a mean of 20 months after surgery. The 4-year primary and secondary patency rates for the endovascular grafts were 66.1% and 72.3% respectively. Six patients required a major amputation, and the limb salvage rate was 88.7%. Four-year patient survival was 37%, with 23 patients dying during this follow-up period. CONCLUSIONS: Endovascular grafts can often be used when conventional procedures are contraindicated or technically impractical. These grafts are a valuable alternative to extraanatomic and aortofemoral bypasses in high-risk patients with aortoiliac occlusive disease and critical ischemia.

Aged↗

PubMed1999

A novel missense mutation, GLY424SER, in Brazilian patients with 21-hydroxylase deficiency.

A previous screening of 17 mutations in 130 Brazilian patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency did not identify mutations in 20% of the alleles. To diagnose these alleles we sequenced the entire CYP21 gene of one Mulatto patient with the simple virilizing form, who had only the R356W mutation in a heterozygous state. We identified a heterozygous G-A transition in codon 424. This mutation leads to a substitution of glycine by serine in a conserved region where glycine is conserved in at least 4 species. This novel mutation eliminates 1 of the restriction sites of the BanI enzyme, which made its screening possible for the whole series. The G424S mutation was found in a compound heterozygous state in 5 families; 4 presented the simple virilizing form, and 1 presented the nonclassical form. Interestingly, 3 of 5 families have a Mulatto origin. This mutation was not identified in 118 CYP21 alleles of normal individuals, ruling out the possibility of a polymorphism, or in 80 pseudogenes, indicating a casual mutagenic event and not a microconversion event. All patients with the G424S mutation presented CYP21P and C4A gene deletions and human leukocyte antigen DR17 on the same haplotype, suggesting a linkage disequilibrium and a probable founder effect. Search for the G424S mutation in other populations will reveal whether it is restricted to the Brazilian patients or if it has a wider ethnic distribution.

Adrenal Hyperplasia, Congenital↗

PubMed1999

Endovascular grafts.

The clinical application of endovascular grafts began with the work of Parodi in 1990, which fused intravascular stent and prosthetic graft technologies. These less invasive devices have been applied to the treatment of arterial aneurysm, long segment occlusive disease, and traumatic vascular injuries. A host of different systems have been developed that exploit the unique properties of balloon, superelastic metal, and vascular graft devices.

Arteries↗

PubMed1998

Endovascular treatment of a ruptured lumbar artery aneurysm: case report and review of the literature.

Lumbar artery aneurysms are uncommon lesions that usually present as pseudoaneurysms secondary to vessel injury. Despite their small size and retroperitoneal location, these lesions are potentially lethal once they rupture. This report describes a ruptured lumbar artery aneurysm which was successfully treated in a minimally invasive fashion. The diagnosis was suggested by computed tomography scan and confirmed with angiography. Successful treatment consisted of placing intravascular metallic coils into the lumbar artery. The literature contains only seven previous reports of ruptured lumbar artery aneurysms and these were managed either operatively or via an endovascular approach. Based upon the outcome of all reported cases, we believe that coil embolization of lumbar artery aneurysms following diagnostic angiography is an appropriate and effective mean of treating these lesions.

Aged↗

PubMed1998

The relationship between apolipoprotein E, dementia, and vascular illness.

The purpose of this study was to concurrently assess the relationship of Apolipoprotein E (APOE) with both dementias and vascular illnesses in the very old. Nine hundred and fifty nine subjects (mean age 85 years) in a long-term care facility were genotyped and cognitively tested with the Mini Mental State Exam. All subjects were studied for the relationship of APOE with atherosclerotic heart disease, hypertension, or stroke without concomitant dementia. Four hundred fifty individuals met criteria for inclusion into one of the following groups: Alzheimer's disease (n = 318), vascular dementia (n = 49), or not demented controls (n = 83) and were investigated for the relationship between APOE and these diagnostic categories. APOE epsilon4 was not associated with atherosclerotic heart disease, hypertension, or stroke without concomitant dementia. The APOE epsilon3 allele was more common in men with atherosclerotic heart disease. In contrast, the APOE epsilon4 allele was more common in patients with Alzheimer's disease (22%) and vascular dementia (26%) than in not demented controls (7%). APOE epsilon4 is associated with dementias in the very old, whereas its relationship with either peripheral or central nervous system vascular disease without dementia is not as robust.

Aged↗

PubMed1998

Varying strategies for endovascular repair of abdominal an iliac artery aneurysms.

Endovascular grafting for abdominal aortic aneurysm has evolved over the past 7 years from Parodi's simple tubular aortic endografts with uniform attachment systems to more complex "modular" designs that begin to provide some flexibility of graft construction at the time of implantation. The future of these systems likely resides in a series of devices that contain sufficient flexibility to permit the operator the option for in situ customization of graft dimensions in accordance with realtime operative/fluoroscopic findings.

Aortic Aneurysm, Abdominal↗

PubMed1998

Endovascular grafting for abdominal aortic aneurysms.

Despite the initial success of endovascular grafts in a very difficult patient population, many problems remain. These procedures are often time-consuming and quite complicated, requiring the close cooperation of an experienced team of vascular surgeons and interventional radiologists. Access may be difficult through occluded, stenotic, and tortuous vessels. Inadequate graft deployment may result in arterial rupture or graft migration, which could potentially lead to acute occlusion of the renal or iliac arteries. Occlusion of the inferior mesenteric artery may result in ischemic colitis. Also, endovascular grafts may fail to exclude an aneurysm from systemic arterial blood pressure, not protecting the patient against impending rupture, and embolization and thrombosis are ever-present dangers. Concerns have been raised regarding radiation exposure and intravenous contrast loads used during these procedures. Clearly, more experience must be gained and technologic advancements made before the use of these devices becomes commonplace, something that may not be too far off in the future.

Aortic Aneurysm, Abdominal↗

PubMed1998

HLA-DRB1*0405 is the predominant allele in Brazilian patients with Vogt-Koyanagi-Harada disease.

Vogt-Koyanagi-Harada (VKH) disease is a rare disorder affecting pigmented structures especially the eye and is the main cause of autoimmune non-infectious uveitis in the Brazilian population. The autoimmune target is believed to be the melanocyte. A strong association of VKH disease with HLA-DR4 in the Japanese population is well known. The same association, albeit with lower relative risks has been found in other populations. A secondary association to HLA-DR1 involving a sequence linked with susceptibility to Rheumatoid Arthritis has also been described. VKH disease is more common in non-Caucasian populations. Brazilian patients of varying ethnic origins have been typed for HLA class II antigens. Several of the features found in other population samples are present. Over half of the patients typed HLA-DR4 (20/37) and typing with sequence-specific oligonucleotides disclosed predominance of the DRB1*0405 allele with a relative risk of 11.76 over the general population. In addition, HLA-DR1 and DQ4 were also present, in patients both positive and negative for HLA-DR4. These results suggest that, as in other autoimmune diseases, multiple overlapping susceptibility factors encoded by the MHC complex contribute to the overall susceptibility for the disease, the major factor however, being the presence of the DRB1*0405 allele.

Adolescent↗

PubMed1998

Impact of transrenal aortic endograft placement on endovascular graft repair of abdominal aortic aneurysms.

PURPOSE: Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. METHODS: Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. RESULTS: There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts (P < or = .05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (> or =50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. CONCLUSION: Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion.

Aged↗

PubMed1998

Endoleaks after endovascular graft treatment of aortic aneurysms: classification, risk factors, and outcome.

PURPOSE: Incomplete endovascular graft exclusion of an abdominal aortic aneurysm results in an endoleak. To better understand the pathogenesis, significance, and fate of endoleaks, we analyzed our experience with endovascular aneurysm repair. METHODS: Between November 1992 and May 1997, 47 aneurysms were treated. In a phase I study, patients received either an endovascular aortoaortic graft (11) or an aortoiliac, femorofemoral graft (8). In phase II, procedures and grafts were modified to include aortofemoral, femorofemoral grafts (28) that were inserted with juxtarenal proximal stents, sutured endovascular distal anastomoses within the femoral artery, and hypogastric artery coil embolization. Endoleaks were detected by arteriogram, computed tomographic scan, or duplex ultrasound. Classification systems to describe anatomic, chronologic, and physiologic endoleak features were developed, and aortic characteristics were correlated with endoleak incidence. RESULTS: Endoleaks were discovered in 11 phase I patients (58%) and only six phase II patients (21%; p < 0.05). Aneurysm neck lengths 2 cm or less increased the incidence of endoleaks (p < 0.05). Although not significant, aneurysms with patent side branches or severe neck calcification had a higher rate of endoleaks than those without these features (47% vs 29% and 57% vs 33%, respectively), and patients with iliac artery occlusive disease had a lower rate of endoleaks than those without occlusive disease (18% vs 42%). Endoleak classifications revealed that most endoleaks were immediate, without outflow, and persistent (71% each), proximal (59%), and had aortic inflow (88%). One patient with a persistent endoleak had aneurysm rupture and died. CONCLUSIONS: Endoleaks complicate a significant number of endovascular abdominal aortic aneurysm repairs and may permit aneurysm growth and rupture. The type of graft used, the technique of graft insertion, and aortic anatomic features all affect the rate of endoleaks. Anatomic, chronologic, and physiologic classifications can facilitate endoleak reporting and improve understanding of their pathogenesis, significance, and fate.

Aged↗

PubMed1998

Endoleak after endovascular graft repair of experimental aortic aneurysms: does coil embolization with angiographic "seal" lower intraaneurysmal pressure?

PURPOSE: To investigate the relation between endoleaks and intraaneurysmal pressure (IAP) and the effect of coil embolization in the management of endoleaks. METHODS: The infrarenal aorta of a dog (n = 15) was replaced by a polytetrafluoroethylene aneurysm containing a pressure transducer. Group I (n = 4) had untreated aneurysms. Group II (n = 4) had endovascularly excluded aneurysms without an endoleak. Group III (n = 7) had aneurysms excluded by means of grafts with a defect that represented the source of an endoleak. After 4 weeks of follow-up study, the endoleaks in group III dogs were subjected to coil embolization. Systolic IAP was measured daily and expressed as a ratio of systolic blood pressure obtained from a forelimb cuff. Arteriography, duplex ultrasonography, and spiral contrast computed tomography were performed to evaluate endoleaks. RESULTS: In group I, the LAP remained close to systolic blood pressure (ratio of 0.96 +/- 0.06), whereas in group II the IAP ratio showed a decline to 0.34 +/- 0.16 (p = 0.0009 group I versus II). After an initial decrease, the IAP ratio in group III stabilized at 0.75 +/- 0.18 (p = 0.003, group II versus III). Aneurysms with an endoleak remained pulsatile with a pulse pressure of 30 +/- 16 mm Hg, which was less than that of untreated aneurysms (62 +/- 15 mm Hg; p < 0.0001 group I versus III). Arteriography and computed tomography revealed "sealing" of endoleaks after coil embolization, but IAP ratio did not decrease (0.76 +/- 0.14) after coil embolization. CONCLUSIONS: Incomplete endovascular aneurysm exclusion caused by an endoleak fails to reduce IAP ratio and may subject the aneurysm to a continued risk for rupture. Although coil embolization resulted in angiographic and computed tomographic sealing, it failed to reduce IAP ratio.

Aneurysm, False↗