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Biomedical subjects

M Maynar

Publications and source records attributed to M Maynar.

At least 19 recordsLinked to original sources
PubMed2005

Treatment of innominate arterial stenosis with self-expanding stent: long-term follow-up.

We report our experience with the use of a self-expanding stent in the treatment of a severe innominate artery stenosis resulting in right upper limb ischemia. A 45-year-old woman was admitted for right upper limb ischemia, asymmetry of the carotid pulse and the lack of pulse in the right upper extremity. The patient had a history of chain smoking, hypertension, hypercholesterolemia, and acute myocardial infarction one year ago. She was diagnosed of the innominate artery stenosis by angiography one year ago at another hospital. At the time of admission her blood pressure was normal in the left arm and absent in the right upper limb. Arteriography showed a severe stenosis subocclusion of the innominate artery with an inverse flow of the ipsilateral vertebral artery. As the patient was not considered to be a surgical candidate due to instable angina, stent placement was indicated. After placement through an axillary approach an angiogram showed a patent right subclavian artery without residual stenosis. Angiographic follow-up showed a patent innominate arterial lumen two years after the procedure. The patient continued to be asymptomatic during six years follow-up. Blood pressure remained normal in both upper extremities, without any ischemic signs. Our experience indicates that placement of an endovascular stent is an effective therapeutic option in selected patients with symptomatic stenosis in the innominate artery when a surgical treatment is contraindicated.

Journal Article↗
PubMed2001

Menopause-induced changes in lipid fractions and total fatty acids in plasma.

UNLABELLED: The purpose of the present work was to evaluate the changes induced by the menopause in plasma lipids and total fatty acids. METHODS: 35 post-menopausal and 25 non-postmenopausal women were included in the study. Plasma triglycerides (TG), total cholesterol (TC) and HDL-C concentrations were detemined enzymatically. Plasma fatty acids were determined by capillary gas chromatography. RESULTS: Total cholesterol was higher (p < 0.05) in the postmenopausal women (6.18 +/- 0.77 mmol/l vs. 5.21 +/- 0.85 mmol/l). No significant changes were observed, however, in TG, HDL-C or LDL-C. The study of plasma fatty acids showed the post-menopausal women to have raised levels (p < 0.05) of stearic acid (C18:0), oleic acid (C18:1), and decrease of arachidonic acid (C20:4). Also noteworthy was the significant decrease (p < 0.001) of the desaturation index D5 (3.82 +/- 1.75) in the post-menopausal women. The SHBG level was lower (p <0.001) in the post-menopausal women (55.98 +/- 20nmol/l) than in the non-menopausal women (68.36 +/- 30 nmol/l). Multivariate analysis revealed correlation between menopause and SHBG (r = -0.3904, p < 0.05), D5 (r = -0.500, p < 0.001), TC (r = 0.3137, p <0.05), stearic acid (r = 03564, p < 0.05) and oleic acid (r = 0.2954, p < 0.05). CONCLUSION: In post-menopausal women, as well as higher total cholesterol, the alterations in plasma fatty acids may constitute an important risk factor for cardiovascular diseases.

Adult↗
PubMed2001

Abdominal decompression plays a major role in early postparacentesis haemodynamic changes in cirrhotic patients with tense ascites.

BACKGROUND: Some cirrhotic patients with tense ascites who undergo paracentesis develop a circulatory dysfunction syndrome, manifested by an increase in plasma renin activity. Recently, a significant inverse correlation between postparacentesis changes in plasma renin activity and systemic vascular resistance has been demonstrated in these patients, suggesting that peripheral arterial vasodilatation could be responsible for this circulatory dysfunction, but the mechanisms by which tense ascites removal induces such changes are unknown AIM: To investigate the role of a decrease in intra-abdominal pressure (IAP) in the development of early postparacentesis haemodynamic changes METHODS: Eleven cirrhotic patients with tense ascites received a large volume paracentesis. A specially designed pneumatic girdle was used to compress the abdomen to avoid a decrease in IAP during ascites removal. Haemodynamic studies were performed before paracentesis, one hour after ascites flow stopped, and 30 minutes after pneumatic girdle deflation RESULTS: When IAP was maintained at its original level, no haemodynamic changes were observed, despite large volume paracentesis. However, a significant decrease in systemic vascular resistance was seen immediately after pneumatic girdle deflation CONCLUSIONS: Early haemodynamic changes after paracentesis are avoided if IAP is maintained at its original level. The abrupt decrease in IAP could be the trigger for the development of the initial haemodynamic changes that eventually produce postparacentesis circulatory dysfunction.

Abdomen↗
PubMed2000

Implantation of a composite bifurcated cryopreserved aorto-iliac-femoral homograft in a patient with Candida albicans endocarditis.

A 35 year old woman, cocaine addict, suffered Candida albicans aortic valve endocarditis complicated with embolisation of infected vegetations in the distal abdominal aorta. She underwent successful staged aortic valve replacement followed by transaortic and transfemoral thrombectomy. One month later an arteriogram disclosed partial occlusion of the left iliac artery, bilateral aneurysmal degeneration of both iliac arteries and right iliac artery-right iliac vein fistula. She was operated again, performing re-laparotomy and re-exploration. A composite bifurcated cryopreserved homograft was implanted end-to-side between the infrarenal abdominal aorta, right external iliac artery and left common femoral artery. The right iliac artery-iliac vein fistula was obliterated with suture. The patient had an uneventful recovery but a relapsing arterio-venous fistula was diagnosed by arteriography. Three months later she underwent percutaneous transluminal closure of the reopened fistula. At present, 17 months after the implantation of the homograft, the patient is symptom-free, on antifungal agents and with arteriographic and clinical evidence of a well-functioning arterial homograft.

Adult↗
PubMed2000

Endovascular repair of abdominal aortic aneurysm in a renal transplant patient.

A 65-year-old man presented with an asymptomatic infrarenal abdominal aortic aneurysm of 6 cm in transverse diameter. Five years before he received a cadaveric renal transplant. The patient also had the following risk factors and associated diseases: arterial hypertension, coronary artery disease, previous myocardial infarction, coronary angioplasty and stent, ileal resection secondary to Chron disease, hepatopathy, hyperlipidemia and hepato-renal cystic disease. The ASA classification was III, IV. Considering previous abdominal operations and risk factors, we decided to repair the aneurysm with a minimal aggression. The aneurysm was successfully approached by an endovascular route implanting a 22x10 bifurcated aorto-iliac endovascular prosthesis. The patient died 13 months later after being diagnosed of enterocolitis by cytomegalovirus complicated with sepsis and lung infection. We consider this less invasive modality of treatment a valid and useful alternative in this high-risk group of patients.

Aged↗
PubMed1999

CO2 as a contrast medium in endoluminal treatment of high flow vascular malformations.

PURPOSE: To evaluate the diagnostic usefulness of CO2 as a radiologic contrast medium in pre and post-embolization of hemodynamically active vascular malformations. MATERIAL AND METHODS: Eight pre-and post-embolization angiographies were performed on five patients with hemodynamically active vascular malformations. In all cases sequentially iodinated contrast medium and CO2 were used. Procedures were performed using Philips Integris V equipped with specific software to process images obtained with CO2 as contrast medium and with a purpose-built gas injector pump. The images were assessed by three interventional radiologists who evaluated the findings by consensus. They were asked whether uptake of the malformations were better, worse or the same with iodinated contrast and CO2. The images were judged according to the following characteristics; quality, the filling in of the contrast in afferent artery of the HAVM, caliber and number of vessels and existence of pathologic communications in HAVM. These characteristics were assessed in all the patients of the study, both before and after embolization. RESULTS: The CO2 angiographic results were compared to those obtained using iodinated contrast material. Iodinated contrast provided superior image quality in all performed studies. The filling of arterial afference of HAVM was well defined with both contrast media. In all performed cases with CO2, the malformations showed more vessels. No inmediate nor subsequent complications developed with CO2 injections, except in one female patient, who presented an intense sensation of cramps in the lower limbs. CONCLUSION: CO2 is a useful diagnostic and assessment tool before and especially during the embolization of hemodynamically active vascular malformations. It improves quantification and uptake of the malformation's vascular architecture, detecting collateral circulation and arteriovenous shunts. It also detects residual post-embolization disease when iodinated contrast agent is unsuccessful.

Adolescent↗
PubMed1999

Animal model of bile duct dilatation created with minimally invasive surgery.

RATIONALE AND OBJECTIVES: The purpose of the study was to evaluate a method of producing obstruction of the common bile duct and concomitant biliary duct dilatation in an animal model. MATERIALS AND METHODS: Laparoscopic placement of a double-balloon occlusion device was used to produce common bile duct obstruction and bile duct dilatation in pigs. RESULTS: One week after the procedure, common bile duct obstruction and dilatation of the biliary tree were demonstrated with either percutaneous transhepatic cholangiography or percutaneous cholecystography. CONCLUSION: The use of this method is technically feasible and provides a useful subacute and chronic animal model of common bile duct obstruction and dilatation of the biliary tree for percutaneous interventional training and research purposes.

Animals↗
PubMed1999

Effects of physical exercise in pre-and postmenopausal women on lipid peroxidation and antioxidant systems.

The effects of moderate physical activity were studied in 19 postmenopausal and 25 premenopausal women on the enzymatic (superoxide dismutase and catalase) and non-enzymatic (vitamins A and E) antioxidant systems and on the processes of lipid peroxidation (malondialdehyde), and to see whether there is any variation in oxidative stress indicators between the postmenopausal and non-menopausal women. The subjects were also studied anthropometrically. At the end of a training period, there was a decrease in body fat percentage and in various skin folds. Neither group presented a rise in lipid peroxidation levels, although there was a significant (p<0.05) rise in superoxide dismutase activity in the postmenopausal women.

Adult↗
PubMed1999

Recanalization of thrombosed superficial femoral arteries with a hydraulic thrombectomy catheter in a canine model.

OBJECTIVE: This experiment was conducted to evaluate efficacy and safety of the Oasis thrombectomy catheter on arterial thrombosis in dogs. MATERIALS AND METHODS: Thrombosis was induced in 18 femoral arteries of nine mongrel dogs. Recanalization of the thrombosed femoral artery was performed using a thrombectomy catheter 7-10 days after thrombus induction. Pre- and postprocedural arterial status was documented by angiography. After mechanical thrombectomy, the animals were sacrificed and the femoral arteries were harvested and examined macro- and microscopically. Additionally, in vitro fragmentation was carried out to determine particle size and distribution from the recovered effluent. RESULTS: Subacute thrombosis was successfully created in 15 femoral arteries. Full recanalization was achieved in 80% (12/15) of the thrombosed femoral arteries without any residual thrombus. No significant downstream embolization was documented angiographically. Endothelial denudation was observed in all the treated arteries along with occasional disruption of the internal elastic lamina. No medial injury was seen. Ninety-eight percent of thrombus was liquefied, defined as particles smaller than 15 microm, by the catheter. Particles larger than 400 microm represented 0.27% of the original clot weight. CONCLUSION: Occluded femoral arteries with 7- to 10-day-old thrombus can be efficiently recanalized with the Oasis catheter in dogs without any significant complication. This thrombectomy catheter appears to be highly effective and safe and requires no sophisticated equipment. Blood loss was our major concern regarding use of this catheter but can be minimized by strictly controlling activation time and restricting the inflow into the vascular segment being treated.

Animals↗
PubMed1999

A simplified arteriovenous malformation model in sheep: feasibility study.

BACKGROUND AND PURPOSE: Recently, a swine model of a cerebral arteriovenous malformation (AVM) has been developed that closely resembles a human AVM of the brain. The creation of such a model requires sophisticated neurointerventional techniques. The purpose of this study was to develop a simple and cost-effective AVM animal model that does not require additional endovascular techniques. METHODS: A surgical anastomosis was created in seven sheep between the common carotid artery and the ipsilateral jugular vein, followed by ligation of the jugular vein above the anastomosis and of the proximal common carotid artery below the anastomosis. The anastomosis was created on the left side in four animals and on the right side in three. Cerebral angiography from the contralateral carotid artery was performed before and immediately after surgery to delineate the relevant cerebral vascular anatomy and to determine the direction of blood flow. RESULTS: An angiographic appearance simulating an AVM was found in all the animals. The ramus anastomoticus and arteria anastomotica functioned as the feeding vessels to the rete mirabile, which represented the nidus in our model, and to the jugular vein, which represented the draining vein from the malformation. Extensive collateral flow through the rete mirabile into the distal segment of the external carotid artery above the ligature was observed angiographically, with retrograde flow through the surgical anastomosis into the jugular vein. CONCLUSION: A simple surgically created experimental model for cerebral AVMs was developed in sheep without the need for additional complex endovascular catheter manipulations of intracranial branches. Such an animal model can substantially reduce the cost of research and training in the neurointerventional or radiosurgical management of AVMs.

Anastomosis, Surgical↗
PubMed1999

Diagnosis and percutaneous treatment of gastrointestinal hemorrhage. Long-term experience.

OBJECTIVE: to report our experience in the diagnosis and treatment of gastrointestinal hemorrhage. METHOD: from April 1987 to April 1997, 196 patients with gastrointestinal hemorrhage (134 men and 62 women) were studied. 165 (84%) were diagnosed as presenting upper gastrointestinal hemorrhage, and 31 (16%) presented lower gastrointestinal hemorrhage. The patients were studied with endoscopy and arteriography, and embolization was prescribed in 131 (67%). Patients with bleeding from esophageal varices were excluded from this study. RESULTS: a bleeding point was identified angiographically in 33% (n = 65) patients. 131 (67%) patients were treated with therapeutic embolization, which was successful in 89% (n = 116) patients. The bleeding was resolved in 80% (n = 93) of the patients. Complications included arterial spasm (n = 12), pain (n = 24), coil migration (n = 8), allergic reaction (n = 2) and celiac trunk dissection (n = 2). During follow-up 16 patients presented rebleeding that stopped after reembolization in 9 cases, whereas in 7 cases surgery was needed. CONCLUSIONS: in our experience, diagnostic angiography and percutaneous therapeutic embolization are effective, less aggressive methods that lead to few complications. Both methods have become indispensable tools in managing patients with gastrointestinal hemorrhage that does not respond to conservative therapy. Even in patients with no evidence of angiographic bleeding, embolization in selected patients is successful.

Adult↗
PubMed1998

[Treatment of dysphagia of malignant origin with the endoprosthesis of Strecker].

OBJECTIVE: To evaluate the effectiveness of metallic Strecker stents for palliation of malignant dysphagia. PATIENTS AND METHODS: From June 1992 to August 1995, 66 Strecker stents were inserted in 55 consecutive patients, 50 male and 5 female, with a mean age of 62 years (range 25-83). The cause of dysphagia was incurable malignant obstruction of the esophagus. Three patients presented with dysphagia grade I, 8 grade II, 27 grade III and 17 grade IV. All the procedures were performed under fluoroscopic control. RESULTS: Exact positioning of the stent was technically feasible in all patients. No procedure-related mortalities or major complications occurred. Immediate complications were transient chest pain (n = 11), blood stain sputum (n = 8) and gastroesophageal reflux (n = 8). During follow-up, 7 patients (12.7%) had recurrent dysphagia due to tumor ingrowth or overgrowth. In these patients an additional overlapping stent was successfully placed in six cases and balloon dilatation in one. Latest evaluation revealed dysphagia grade O in five patients (9%), 10 dysphagia grade I (18%), 14 grade II (25%), 13 grade III (23.6%) and seven grade IV. CONCLUSIONS: Implantation of Strecker stents is an effective and safe method of palliating severe malignant dysphagia. Placement of the stents was feasible without major procedure complications.

Adult↗
PubMed1998

Transcatheter embolization of symptomatic hepatic venous malformations.

The aim of this study was to evaluate our results in treatment and management of symptomatic hepatic venous malformations using transcatheter embolization therapy. From 1991 to 1997 five venous malformations were embolized in one man and four women ranging in age from 31 to 50 years. All patients presented nonspecific abdominal pain and were assessed in the general surgery unit. Percutaneous embolization was recommended. In all cases polyvinyl alcohol was used to embolize the afferent arterioles. Clinical and echographic control follow-up was carried out on an outpatient basis in our Vascular and Interventional Radiology Unit. Embolization was possible in all cases. No complications developed during the procedure, except in one case where the subject suffered a spasm of the hepatic artery. Mean follow-up time was 42 months (6-73 months). Four patients remained asymptomatic during the entire follow-up period, whereas one patient required reembolization. In our experience, transcatheter embolization of hepatic venous malformations is a noninvasive technique which requires few admissions and presents few complications. With further use, it could become the treatment of choice in symptomatic hepatic venous malformations as an alternative to surgery.

Adult↗
PubMed1998

Intramuscular low flow vascular malformations: treatment by means of direct percutaneous embolization.

PURPOSE: Intramuscular hemodynamically inactive vascular malformations are infrequent entities whose surgical treatment is often impossible, crippling, or inefficient. We describe a nonsurgical therapeutic approach consisting on embolization by direct puncture with sclerosant substances. METHODS: Four patients have been treated from April to November 1994, three female and one male, ranging in age from 13 to 31 years. Three vascular malformations were located in the quadriceps and one in the deltoid muscle. The point of access was determined with information provided by MR. The skin was cleaned with an antiseptic solution and puncture was performed with a 22 gauge Chiva needle. Blood flow inside the malformation was slow in all cases and no afference to the normal venous system was detected. We embolized with 5-15 cc (mean 7.5 cc) of a mixture of ethibloc and ethanol. RESULTS: The mean follow-up period was 17 months (range 14-21). All patients remain asymptomatic and have resumed normal daily life activities. There were no complications. CONCLUSION: Percutaneous embolization by direct puncture of intramuscular vascular malformations is a feasible and simple procedure. Our preliminary results are promising, although more extensive studies need to be to performed in order to reach definite conclusions.

Adolescent↗
PubMed1998

[Endovascular treatment of abdominal aorta aneurysms using bifurcated endoprosthesis].

OBJECTIVE: To obtain an initial assessment of the implantation technique of bifurcated vascular endoprothesis in the treatment of abdominal aorta aneurysms (AAA). METHODS: Eleven Vanguard type endoprostheses were implanted in eleven patients with infra-renal aortic aneurysm. The technique was performed with surgical approach in one femoral artery, and percutaneously in the other. The procedure was performed with epidural anesthesia. RESULTS: A technical success--i.e., the exclusion of the aneurysm--was obtained in all cases. No technical complications occurred during the procedure. Three patients had low degree contrast leak in the angiographic control immediately after the procedure. Eight patients had low grade fever in the immediate follow-up which resolved with medical therapy, two patients had hematomas in the approach sites, one renal infarction, one ileus for two days, another one for five days, and three patients had lymphatic effusion. During follow-up the patients with leak had to undergo co-axial endoprosthesis implantation. CONCLUSIONS: It is our view that bifurcated vascular endoprostheses offer a valid alternative in the treatment of AAA. The procedure can be performed with epidural anesthesia and sedation, with a low rate of complications. The long term follow-up and the perfecting of the approach and resection systems will ultimately dictate their usefulness in this and other vascular conditions.

Aged↗
PubMed1998

[Percutaneous extraction of a foreign body from the right ventricle. Clinical case].

Percutaneous retrieval of intravascular foreign bodies has emerged as a standard method of treatment, which audits major surgery. This procedure was performed in a patient with a fragment of a broken introducer sheath located in the right ventricle with risk of arrhythmias. Extraction was difficult because the sheath was trapped in the tendinous cords. The foreign body was embolized to the pulmonary artery and extraction was performed. No clinically significant complications occurred.

Adolescent↗