Browsing by Author "Irarrazaval, MJ"

Now showing 1 - 5 of 5
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    A numerical model for simulation of bioremediation of hydrocarbons in aquifers
    (GROUND WATER PUBLISHING CO, 1998) Munoz, JF; Irarrazaval, MJ
    A numerical model was developed to describe the bioremediation of hydrocarbons in ground water aquifers considering aerobic degradation. The model solves the independent transport of three solutes (oxygen, hydrocarbons, and microorganisms) in ground water flow using the method of characteristics. Interactions between the three solutes, in which oxygen and hydrocarbons are consumed by microorganisms, are represented by Monod kinetics, solved using a Runge-Kutta method. Model simulations showed good correlation as compared with results of soil column experiments. The model was used to estimate the time needed to remediate the columns, which varied from one to two years.
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    Comparison of two doses of aprotinin in patients receiving aspirin before coronary bypass surgery
    (ARNOLD, HODDER HEADLINE PLC, 2000) Moran, SV; Lema, G; Medel, J; Irarrazaval, MJ; Zalaquett, R; Garayar, B; Flaskamp, R
    This study was designed to evaluate efficacy and tolerability of two different doses of aprotinin in patients receiving aspirin before undergoing coronary artery bypass grafting. Forty-two patients were randomized to receive either placebo (group I), or aprotinin in doses of 4 000 000 KIU (group II) or 6 000 000 KIU (group III). Drug efficacy was determined by measuring postoperative blood loss and transfusion of blood products. Both doses were effective in reducing blood loss and transfusion requirements. Blood loss through thoracotomy drainage was 450 +/- 224, 182 +/- 144, 142 +/- 98 mi, respectively, for control and treatment groups II and III (p = 0.0001). The numbers of patients with blood transfusions were seven (50%), two (17%) and two (17%) for group I and treatment groups II and ill, respectively (p = 0.10). Tolerability was excellent and complications few and reversible.
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    Long-term results of repair versus replacement for degenerative mitral valve regurgitation
    (SOC MEDICA SANTIAGO, 2005) Zalaquett, R; Scheu, M; Campla, C; Moran, S; Irarrazaval, MJ; Becker, P; Arretz, C; Cordova, S; Braun, S; Chamorro, G; Godoy, I
    Background- Mitral valve repair is considered better than mitral valve replacement for degenerative mitral regurgitation. Aim To evaluate late clinical results of;mitral valve repair as compared to mitral valve replacement in patients with degenerative mitral regurgitation. Patients and methods: All patients subjected to open heart surgery for degenerative mitral regurgitation between 1990 and 2002 were assessed for surgical mortality late cardiac and overall mortality, reoperation, readmission to hospital, functional capacity and anticoagulant therapy. Eighty eight patients (48 males) bad mitral valve repair and 28 (79 males) bad mitral valve replacement (23 with a mechanical prosthesis). Mean age was 59.9 +/- 14.8 (SD) and 61.3 +/- 14.6 years, respectively. Sixty three percent of patients with repair and 50% of those with, valve replacement were in functional class III or IV before surgery. Results: Operative mortality was 2.3% for mitral valve repair and 3.6% for mitral valve replacement (NS). Also, there was no statistical difference in the need of reoperation during the follow-up period between both procedures (2.3% and 0%, respectively). Ninety four percent of the replacement patients but only 269,6 of the repair patients were in anticoagulant tberapy at the end of the follow-up period (p < 0.001). Ten years survival rates were 82 +/- 6% for mitral valve repair and 54 +/- 1.1% for replacement. The corresponding cardiac related survival rates were 89 +/- 6% and 79 +/- 10%. At the end of follow-up, all surviving patients were in functional class I or II. Ten years freedom from cardiac event rates (death, cardiac related rehospitalization and reoperation) were 90 +/- 3% for mitral valve repair and 84 +/- 6% for replacement. Conclusion: Repair of the mitral valve offers a better overall survival and a better chance of freedom from cardiac events as well as need for anticoagulation 10 years after surgery (Rev Med Chile 2005; 133: 1139-46).
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    Predictors of radial artery patency for coronary bypass operations
    (ELSEVIER SCIENCE INC, 2001) Moran, SV; Baeza, R; Guarda, E; Zalaquett, R; Irarrazaval, MJ; Marchant, E; Deck, C
    Background. Few data exist regarding angiographic predictors of radial artery patency for coronary bypass grafting, and the benefit of calcium antagonists is not clear.
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    Valve repair surgery for incompetent bicuspid aortic valves
    (SOC MEDICA SANTIAGO, 2005) Zalaquett, R; Campla, C; Scheu, M; Cordova, S; Becker, P; Moran, S; Irarrazaval, MJ; Baeza, C; Arretz, C; Braun, S; Chamorro, G; Godoy, I; Yanez, F
    Background Surgical valve repair is a good alternative for correction of incompetent bicuspid aortic valve. Aim: to report the early and late surgical, clinical and ecochardiographic results of surgical repair of incompetent bicuspid aortic valves. Patients and methods: Retrospective review of medical records of 18 patients aged 19 to 61 years, with incompetent bicuspid aortic valve in whom a valve repair was performed. Four patients had infections endocarditis and 17 were in functional class I or II. Follow up ranged from 3 10 113 months after surgery. Results: A triangular resection of the prolapsing larger cusp, which included the middle raphe, was performed in 17 cases, in 73 of these, a complementary subcommisural annuloplasty was performed. In the remaining case, with a perforation of the non-coronary cusp, a pericardial patch was implanted; this procedure was also performed in 2 other cases. In 3 cases large vegetations were removed. Postoperative transesophageal echocardiography showed no regurgitation in 11 patients (62%) and mild regurgitation in 7 (38%). There was no operative morbidity or mortality. There were no deaths during the follow-up period. In,3 patients (17%) the aortic valve was replaced with a mechanical prosthesis, 8 to 108 months after the first operation. Reoperation wets not needed in 93% 6,4% at 1 year and 85% 9,5% at 5 years, these patients were all in functional class 1 (it the end of the follow-lip period. 60% bad no aortic regurgitation, 20% had mild and 20% moderate aortic regurgitation on echocardiographic examination. A significant reduction of the diastolic diameter of the left ventricle was observed but there were no significant changes in systolic diameter or shortening fraction. Conclusions Surgical repair of incompetent bicuspid aortic valves has low operative morbidity and mortality and has a low risk of reoperation.