León Valdivieso

University of Buenos Aires, Buenos Aires, Buenos Aires F.D., Argentina

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Publications (23)47.82 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Critical limb ischemia complicates peripheral artery disease leading to tissue damage and amputation. We hypothesized that modifying adipose stromal cells (ASCs) to overexpress human vascular endothelial growth factor 165 (VEGF) would limit ischemic muscle damage to a larger extent than nonmodified ASCs. Rabbits with critical hindlimb ischemia were injected with allogeneic abdominal fat-derived ASCs transfected with plasmid-VEGF165 (ASCs-VEGF; n=10). Additional rabbits received nontransfected ASCs (ASCs; n=10) or vehicle (placebo; n=10). One month later, ASCs-VEGF rabbits exhibited significantly higher density of angiographically visible collaterals and capillaries versus placebo (both P<0.05) but not versus ASCs (both P=NS). Arteriolar density, however, was increased in both ASCs and ASCs-VEGF groups (both P<0.05 versus placebo). ASCs-VEGF and ASCs showed comparable post-treatment improvements in Doppler-assessed peak systolic velocity, blood pressure ratio, and resistance index. Ischemic lesions were found in 40% of the muscle samples in the placebo group, 19% in the ASCs-VEGF group, and 17% in the ASCs groups (both P<0.05 versus placebo, Fisher test). In a rabbit model of critical limb ischemia, intramuscular injection of ASCs genetically modified to overexpress VEGF increase angiographically visible collaterals and capillary density. However, both modified and nonmodified ASCs increase arteriolar density to a similar extent and afford equal protection against ischemia-induced muscle lesions. These results indicate that modifying ASCs to overexpress VEGF does not enhance the protective effect of ASCs, and that arteriolar proliferation plays a pivotal role in limiting the irreversible tissue damage of critical limb ischemia. © 2014 American Heart Association, Inc.
    Arteriosclerosis Thrombosis and Vascular Biology 11/2014; · 6.34 Impact Factor
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    ABSTRACT: Concurrent severe carotid and cardiac disease is a challenging situation where staged surgery is probably the most common strategy. However, in patients with an unstable clinical presentation, the best approach is still a matter of debate. To report in-hospital and midterm outcome in patients who received carotid artery stenting and synchronous cardiac surgery. From June 1998 to July 2012, 54 consecutive patients who were treated at a high-volume university medical center with this hybrid approach were included in the study. All of the patients received carotid angioplasty while being administered aspirin and regular unfractionated heparin. Then, all of the patients were immediately transferred to the operating room for coronary and/or cardiac valve surgery. All of the patients were administered aspirin and clopidogrel once bleeding was ruled out, after surgery. There were five in-hospital surgical related deaths, and no patient suffered a stroke or required carotid urgent re-intervention. At follow-up (55±28 months; range 1-144 months), there were no new neurological deficits, while one additional death occurred. In this series, synchronous carotid stenting and cardiac surgery were feasible with an acceptable complication rate in a high-surgical-risk population, which could not undergo staged procedures.
    Cardiology journal 02/2014; · 1.15 Impact Factor
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    ABSTRACT: Thromboembolic pulmonary disease is challenging for physicians when diagnosed in acute, sub-acute and chronic clinical patients, not only due to its morbi-mortality, but also because of its complex therapeutic management. Severity of the acute condition and potential commitment of right ventricular systolic function require therapeutic strategies, sometimes combined, in order to change the disease's course, optimizing patient survival. Pharmacological and mechanical thrombolysis are useful therapeutic tools for patients suffering from severe acute pulmonary embolism. This study refers to a young woman who developed a sub-massive pulmonary embolism, of sub-acute onset. She underwent the combined sequential therapeutic strategy of pharmacological and mechanical thrombolysis with successful outcome.
    Medicina 01/2014; 74(2):124-126. · 0.42 Impact Factor
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    ABSTRACT: Objectives: To report the incidence and predictors of moderate/severe radial artery spasm (RAS) in patients undergoing cardiovascular percutaneous procedures through a transradial approach (TRA) in center with TRA expertise. Background: Data regarding the actual rate of clinically meaningful RAS are limited due to difference in study designs and operator expertise. Methods: The RAS registry, an international (14 centers from Argentina, Chile, India, Indonesia, Macedonia, The Netherlands and United States of America) registry that included 1868 patients undergoing TRA cardiovascular procedures (63.5% diagnostic and 56.5% therapeutic).All selected centers used TRA as default strategy in the cardiac catheterization laboratory. Throughout 2012, each center included all consecutive TRA cases (during a two-month period) into a dedicated database covering clinical characteristics as well as procedural topics related to TRA patterns and RAS occurrence. Results: The incidence of moderate/severe RAS was 2.7%. Only 0.7% of patients required crossover (8 to transfemoral and 5 to contralateral TRA). Patients with moderately/severe spasm were more frequently females, had a history of dyslipidemia, received more often a 7F sheath and more puncture attempts than patients without spasm. By multivariate analysis, the need for more than one attempt and the use of a 7 F sheath were independent predictors of the development of moderate/severe RAS. Conclusion: The incidence of moderate/severe RAS is low in centers with a default TRA. Its development appears to be strongly related to the numbers of puncture attempts and the use of large sheaths. © 2013 Wiley Periodicals, Inc.
    Catheterization and Cardiovascular Interventions 06/2013; · 2.51 Impact Factor
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    ABSTRACT: Aims: To assess the results of transcatheter aortic valve implantation (TAVI) using the Medtronic CoreValve prosthesis (Medtronic, Minneapolis, Minnesota), without balloon predilation, in high-risk patients with degenerated severe aortic stenosis. Methods and Results: 51 consecutive patients who underwent direct TAVI, 98% through a transfemoral approach (TF). Patients were 79±8 years of age, 74% in New York Heart Association classes III or IV and at high risk for surgical valve replacement (mean logistic EuroScore 20±15). Mean aortic valve area was 0.7±0.2 cm2. Procedural success rate was 94.2%. In-hospital, there were 2 deaths, 1 minor stroke with minimal sequelae, and 14 (28%) pacemaker implantation. At 30 days, there was 1 additional stroke and no new deaths. The mean postprocedural transprosthetic gradient was 15±5 mm Hg; periprosthetic severe regurgitation was absent and moderate in 1 case. After a median follow-up of 7 months, there were 5 additional deaths (2 cardiac), while 84% of survivors were in New York Heart Association classes I or II. Conclusions: These results suggest that direct CoreValve implantation in patients with severe aortic stenosis is feasible and may lead to hemodynamic and clinical improvement in patients who are poor candidates for aortic valve surgery, pending confirmation in larger series with longer follow-up. © 2013 Wiley-Liss, Inc.
    Catheterization and Cardiovascular Interventions 04/2013; · 2.51 Impact Factor
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    ABSTRACT: Outcomes of Direct Implantation of Self-Expandable Aortic Valve Prosthesis for Severe Aortic Stenosis
    Revista argentina de cardiología. 10/2012; 80(5):360-365.
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    ABSTRACT: OBJECTIVES: We aimed to assess safety and, secondarily, the efficacy of intramyocardial high-dose plasmid-VEGF165 (pVEGF165) gene transfer in no-option patients with coronary artery disease (CAD) BACKGROUND: Controlled trials of pVEGF165 in CAD have shown little benefit. One possible reason is shortness of dosage. We have shown in large mammalian models of chronic myocardial ischemia and acute myocardial infarction that intramyocardial pVEGF165 at doses significantly higher than those used in recent phase II trials is safe and efficacious on myocardial perfusion, left ventricular function and infarct size limitation METHODS: Using an injection catheter, 10 patients with severe CAD not amenable for revascularization received 10 intramyocardial injections of 0.38 mg (total dose 3.8 mg) pVEGF165 in zones exhibiting myocardial ischemia, as assessed by combined stress 99mTc-sestamibi single photon emission computed tomography and stress echocardiography RESULTS: No serious adverse events related to either VEGF or the injection procedure occurred over 2 years follow-up. One patient suffered femoral artery thrombosis after a follow-up coronary angiography, successfully resolved with medical treatment. Six patients suffered uncomplicated coronary ischemic events during the second year follow-up. Angina functional class decreased from 2.6±0.2 to 1.2±0.3 (mean±SEM, P<0.05), quality of life increased from 56.9±3.2 to 82.6±2.4 (P<0.05), the summed difference score of myocardial perfusion decreased from 13.4±2 to 7.7±1.8 (P<0.04) and stress ejection fraction did not change (44.2±3.6 to 47.8±3.1%, P=NS) CONCLUSIONS: High-dose intramyocardial pVEGF165 is safe at 2 years follow-up in patients with severe CAD. The efficacy results observed must be taken cautiously given the uncontrolled, open-label study design. © 2012 Wiley Periodicals, Inc.
    Catheterization and Cardiovascular Interventions 07/2012; · 2.51 Impact Factor
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    ABSTRACT: We evaluated the incidence of clinical events after implantation of the TAXUS Liberté paclitaxel-eluting stent in saphenous vein graft (SVG) lesions in an unselected patient population. The OLYMPIA (TAXUS Liberté Post-Approval Global Registry) program gathered data on 21 954 patients receiving at least 1 TAXUS Liberté stent, including 345 patients with SVG lesions. All cardiac events were monitored with independent adjudication of end points. Patients enrolled at procedure started with no mandated inclusion/exclusion criteria. In SVG-OLYMPIA (n = 345), baseline comorbidities/complex disease were more frequent than the rest of the OLYMPIA (n = 21 560). SVG-OLYMPIA had similar cardiac death, target vessel revascularization, and definitive stent thrombosis rates than the rest of OLYMPIA. Despite higher baseline risk, the SVG-OLYMPIA had similar 12-month clinical outcome than the rest of the OLYMPIA registry, confirming the safety and efficacy of the TAXUS Liberté stent in this high-risk group.
    Angiology 01/2012; · 2.37 Impact Factor
  • Medicina 10/2011; 71(5):437-440. · 0.42 Impact Factor
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    ABSTRACT: Executive functions are crucial for organizing and integrating cognitive processes. While some studies have assessed the effect of carotid artery stenting (CAS) on cognitive functioning, results have been conflicting. The object of this study was to assess the effect of CAS on cognitive status, with special interest on executive functions, among patients with severe asymptomatic internal carotid artery (ICA) stenosis. The authors prospectively assessed the neuropsychological status of 20 patients with unilateral asymptomatic extracranial ICA stenosis of 60% or more by using a comprehensive assessment battery focused on executive functions before and after CAS. Individual raw scores on neuropsychological tests were converted into z scores by normalizing for age, sex, and years of education. The authors compared baseline and 3-month postoperative neuropsychological scores by using Wilcoxon signed-rank tests. The mean preoperative cognitive performance was within normal ranges on all variables. All patients underwent a successful CAS procedure. Executive function scores improved after CAS, relative to baseline performance as follows: set shifting (Trail-Making Test Part B: -0.75 ± 1.43 vs -1.2 ± 1.48, p = 0.003) and processing speed (digit symbol coding: -0.66 ± 0.85 vs -0.97 ± 0.82, p = 0.035; and symbol search: -0.24 ± 1.32 vs -0.56 ± 0.77, p = 0.049). The benefit of CAS for working memory was marginally significant (digit span backward: -0.41 ± 0.61 vs -0.58 ± 0.76, p = 0.052). Both verbal (immediate Rey Auditory Verbal Learning Test: 0.35 ± 1.04 vs -0.22 ± 0.82, p = 0.011) and visual (delayed Rey-Osterrieth Complex Figure: 0.27 ± 1.26 vs -0.22 ± 1.01, p = 0.024) memory improved after CAS. The authors found a beneficial effect on executive function and memory 3 months after CAS among their prospective cohort of consecutive patients with unilateral and asymptomatic ICA stenosis of 60% or more.
    Journal of Neurosurgery 09/2011; 116(1):179-84. · 3.15 Impact Factor
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    ABSTRACT: We report our experience using transradial access (TRA) for carotid artery stenting (CAS). Eighty-eight patients underwent CAS using a nonfemoral approach, 79 of them by TRA. Carotid artery stenting was performed using standard techniques with a long hydrophilic sheath. Mean age was 69.5 years. A total of 46 patients were symptomatic and 34 were asymptomatic. Transradial access and procedural success were achieved in 98.8% and 96.6% of the cases, respectively. There were no deaths, myocardial infarction, or radial access site complications. In all, 2 patients sustained a stroke, 1 hemorrhage, and 1 ischemia. Carotid artery stenting using TRA was safe and technically feasible.
    Vascular and Endovascular Surgery 08/2011; 45(6):499-503. · 0.88 Impact Factor
  • León Valdivieso, Miguel Cerdá, Oscar Méndiz
    Revista argentina de cardiología. 06/2011; 79(3):266-266.
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    ABSTRACT: To report our experience in patients with critical limb ischemia (CLI) due to isolated below-the-knee (BTK) arterial lesions. Between 1992 and 2009, we performed 2747 peripheral angioplasties, while 2.8% (78 of 2747) were only BTK and were included in the present study. Mean age was 70.2 ± 11 years, 58.4% had diabetic, 85.7% were smokers, and 20.8% had chronic renal failure. Baseline Rutherford class: 50 patients with class IV and 27 with class V to VI. Angiographic and clinical success were 97.4% and 90.91%, respectively. At 30 days, there were no deaths, 2 patients had acute vessel closure and 2 major amputation. At long-term follow-up (22.4 ± 9.6 months), there were 7 unrelated deaths (10%), 5 amputations (7.1%), 3 reinterventions (4.2%), while 16 patients remained symptomatic. Overall amputation and amputation plus claudication-free survival were 90% and 70%, respectively. Endovascular treatment of BTK lesions represents a safe and effective treatment option to patients with CLI.
    Angiology 03/2011; 62(5):359-64. · 2.37 Impact Factor
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    ABSTRACT: Chest pain is a frequent symptom in patients with pulmonary hypertension of any etiology. Its pathophysiology has not been clearly established, the proposed causes are ischemia due to increased right ventricle wall stress, transient increased pulmonary hypertension resulting in acute pulmonary artery dilatation and external compression of the left main coronary artery (LMCA) by a dilated pulmonary artery. We report and discuss here three cases where the association between chest pain and compression of the LMCA by a dilated pulmonary artery could be shown, and they were treated with coronary stenting.
    Medicina 01/2011; 71(5):437-40. · 0.42 Impact Factor
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    ABSTRACT: Une femme diabétique de 62 ans était adressée à notre établissement avec une histoire de six mois d’hypertension pulmonaire et d’insuffisance cardiaque droite progressive. La tomodensitométrie thoracique et l’angiographie pulmonaire montraient une masse de l’artère pulmonaire. En raison de l’état précaire de la patiente, un kissing-stenting palliatif des deux artères pulmonaires était fait avec des résultats angiographiques optimaux et une amélioration clinique manifeste. Au suivi de 5 mois, les deux stents étaient perméables et une perfusion satisfaisante des poumons était observée bilatéralement.
    Annales de Chirurgie Vasculaire 12/2010; 24(8).
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    ABSTRACT: A 62-year-old diabetic female was referred to our institution with a 6-month history of pulmonary hypertension and worsening right-sided heart failure. Computed tomography of the chest and pulmonary angiogram revealed a pulmonary artery mass. Due to patient's frail state, palliative kissing stenting to both pulmonary arteries was performed with optimal angiographic results and overt clinical improvement. At 5 month follow-up, both stents were patent and adequate lung perfusion was observed bilaterally.
    Annals of Vascular Surgery 11/2010; 24(8):1135.e9-12. · 0.99 Impact Factor
  • Journal of the American College of Cardiology 03/2010; 55(10). · 14.09 Impact Factor
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    ABSTRACT: BACKGROUND: Carotid lesions are observed in 8% to 14% of cardiovascular surgery candidates and increase the risk of perioperative stroke. This is particularly important in patients with coronary disease and/or severe valve disease who are not candidate to revascularization procedures at different time points. We assessed the results of a hybrid strategy, where carotid angioplasty and cardiovascular surgery were performed sequentially with an interval of a few hours. METHOD: Carotid lesions > 70% in symptomatic patients and > 80% in asymptomatic patients were treated. Acetylsalicylic acid was administered prior to carotid stenting and heparin was administered at the time of the procedure. Once the percutaneous intervention was over, patients were transferred to the surgery room to carry out the cardiovascular procedure. Clopidogrel was administered 8 hours after the end of the surgery. RESULTS: Forty-three consecutive patients were included and treated with the hybrid strategy. Male patients (81%) were prevalent, with mean age of 70.5 ± 8.5 years, and 25.6% were diabetic. A cerebral protection system was used in 42 patients and stents were implanted in all of them. Coronary artery bypass graft (CABG) was performed in 20 patients, CABG + aortic valve replacement (AVR) in 18, CABG + ascending aorta repair in 1, CABG + mitral valve annuloplasty in 1, CABG + mitral valve replacement (MVR) in 1, AVR in 1 and MVR in 1. Hospital results showed 4 deaths (2 due to multiple organ failure, 1 due to heart failure and 1 to bleeding), 1 case of perioperative acute myocardial infarction and no strokes. Late follow-up was performed in all of the patients at 25 ± 15 months. After hospital discharge, there were two deaths not related to the percutaneous or surgical procedures and no neurological events. CONCLUSION: A hybrid strategy combining carotid stenting and cardiovascular surgery is feasible and safe with an acceptable complication rate. It may be a good option in clinically unstable patients, however, further studies with a large number of patients are required to reproduce our findings.
    Revista Brasileira de Cardiologia Invasiva. 06/2009; 17(2):190-195.
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    ABSTRACT: Vascular endothelial growth factor (VEGF) gene transfer-mediated angiogenesis has been proposed for peripheral artery disease. However, protocols using single administration have shown little benefit. Given that the transient nature of VEGF gene expression provokes instability of neovasculature, we hypothesized that repeated administration would provide efficient tissue protection. We thus compared single vs repeated transfection in a rabbit model of hindlimb ischemia by injecting a plasmid encoding human VEGF165 (pVEGF165) at 7 (GI, n=10) or 7 and 21 (GII, n=10) days after surgery. Placebo animals (GIII, n=10) received empty plasmid. Fifty days after surgery, single and repeated administration similarly increased saphenous peak flow velocity and quantity of angiographically visible collaterals. However, microvasculature increased only with repeated transfection: capillary density was 49.4+/-15.4 capillaries per 100 myocytes in GI, 84.6+/-14.7 in GII (P<0.01 vs GI and GIII) and 49.3+/-13.6 in GIII, and arteriolar density was 1.9+/-0.6 arterioles per mm2 in GI, 3.0+/-0.9 in GII (P<0.01 vs GI and GIII) and 1.5+/-0.6 in GIII. Muscle lesions were reduced only within repeated transfection. With single administration, gene expression peaked at 7 days and declined rapidly, but with repeated administration, it remained positive at 50 days. At 90 days of repeated transfection (additional animals), gene expression decreased significantly, but neovessel densities did not. Thus, repeated, but not single, VEGF gene transfection resulted in increased microvasculature, which, in turn, afforded effective protection against ischemic muscle damage.
    Gene therapy 04/2009; 16(6):716-23. · 4.75 Impact Factor
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    ABSTRACT: Concurrent severe carotid and cardiac disease is a challenging situation where staged surgery is probably the most common strategy, although it is still controversial. We report in-hospital and midterm outcome of 30 patients who received carotid stenting and synchronous cardiac surgery. All received carotid stenting under aspirin and regular unfractioned heparin (UFH) and were immediately transferred to the operating room for coronary and/or cardiac valve surgery. All patients received aspirin and clopidogrel once bleeding was ruled out, after surgery. In-hospital complications were: three surgical related deaths, one TIA, and no patient suffered stroke or myocardial infarction. Hospital stay was 14 +/- 11.8 days. Survivors were followed for 18.4 +/- 14 months. There were two non-related deaths, but no stroke nor cardiac or carotid reinterventions. In conclusion, this small series showed that synchronous carotid stenting and cardiac surgery was feasible with an acceptable complication rate in a high-surgical-risk population which could not undergo staged procedures.
    Catheterization and Cardiovascular Interventions 10/2006; 68(3):424-8. · 2.51 Impact Factor

Publication Stats

46 Citations
47.82 Total Impact Points

Institutions

  • 2013
    • University of Buenos Aires
      Buenos Aires, Buenos Aires F.D., Argentina
  • 2012
    • Fundación Favaloro
      Buenos Aires, Buenos Aires F.D., Argentina
  • 2010
    • Favaloro University
      Buenos Aires, Buenos Aires F.D., Argentina