Morán S

Adenosine 5′-triphosphate and neuropeptide Y are co-transmitters in conjunction with noradrenaline in the human saphenous vein

Human saphenous veins were used to assess the cooperative participation of adenosine 5‐triphosphate (ATP), neuropeptide Y (NPY), and noradrenaline (NA) in the vasomotor responses elicited following electrical depolarization of the perivascular nerve terminals. Rings from recently dissected human biopsies were mounted to record isometric muscular contractions; the motor activity elicited in the circular muscle layer following electrical depolarization (2.5–20 Hz, 50 V, 0.5 msec) were recorded. Incubation of the biopsies with either 100 nM tetrodotoxin (TTX) or 1 μM guanethidine abolished the vasomotor response elicited by electrical nerve depolarization. The independent application of either ATP or NA to vein rings induced concentration‐dependent contractions. Tissue incubation with 30 μM suramin or 10 nM prazosin produced 10 fold rightward displacements of the α,β‐methylene ATP and NA concentration‐response curves respectively. NPY contracted a limited number of biopsies, the vasoconstriction elicited was completely blocked by 1 μM BIBP 3226. A 5 min incubation of the biopsies with 10–100 nM NPY synergized, in a concentration‐dependent fashion, both the ATP and the ATP analogue‐induced contractions. Likewise, tissue preincubation with 10 nM NPY potentiated the vasomotor responses evoked with 20–60 nM NA. Neither suramin, BIBP 3226, nor prazosin was individually able to significantly modify the derived frequency‐tension curves. In contrast, the co‐application of 30 μM suramin and 10 nM prazosin or 30 μM suramin and 1 μM BIBP 3226, elicited a significant (P<0.01) downward displacement of the respective frequency‐tension curves. The simultaneous application of the three antagonists–30 μM suramin, 1 μM BIBP 3226 and 10 nM prazosin–caused a significantly greater displacement of the frequency‐tension curve than that achieved in experiments using two of these antagonists. Electrically‐evoked vasomotor activity is blocked to a larger extent by tissue incubation with 2.5 μM chloroethylclonidine and 30 μM suramin rather than with 10 nM 5 methyl urapidil and 30 μM suramin. As a result, the α1‐adrenoceptor involved in the vasomotor activity has tentatively been associated with the α1B adrenoceptor family subtype. Results support the physiological role of ATP in sympathetic neurotransmission. The present results are consistent with the working hypothesis that human sympathetic vasomotor reflexes involve the coordinated motor action of ATP, NPY, and NA acting on vascular smooth muscle cells. The present results support the concept of sympathetic co‐transmission in the human saphenous vein.

Tratamiento endovascular del aneurisma de aorta torácica descendente

Background: The natural history of aneurysms ends in rupture and death. In 1990 the first endovascular exclusion of an aneurysm, using an endoluminal graft implanted through the femoral arteries was performed. More recently, the same procedure has been used for aneurysms of the thoracic aorta. Aim: To report our experience with endovascular treatment of thoracic aorta aneurysms. Material and methods: Analysis of 14 patients (nine male), aged 30 to 79 years, treated between May 2001 and August 2002. Results: The mean diameter of the aneurysms was 6.9 cm. The etiology was atherosclerotic in nine patients. The Excluder device (Goreâ) was preferentially used. There was no operative mortality or paraplegia. One patient had a transient leg monoparesis that reverted completely. No patient had type I endoleaks. Two patients had type II endoleaks on discharge, that sealed spontaneously. In a follow up, ranging from 2 to 17 months, one patient died of a bronchopneumonia and no aneurysm rupture has been detected. Conclusions: The short term results of endoluminal treatment of thoracic aorta aneurysms are excellent. This treatment is less invasive and has less complications than conventional surgery (Rev Med Chile 2003; 131: 617-22)

Comparison of two doses of aprotinin in patients receiving aspirin before coronary bypass surgery

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 ml, 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 III, respectively (p = 0.10). Tolerability was excellent and complications few and reversible. In conclusion, high and medium doses of aprotinin were well tolerated and reduced bleeding and transfusion requirements in patients submitted to coronary bypass surgery under the effects of aspirin.

Mixoma cardiaco: Caracterización clínica, métodos diagnósticos y resultados alejados del tratamiento quirúrgico durante tres décadas de experiencia

Background: Cardiac myxoma is the most common primary cardiac tumor. Aim: To evaluate clinical aspects, diagnostic methods and surgical outcomes in patients with cardiac myxoma. Patients and Methods: All patients who underwent surgical resection of a cardiac myxoma between January 1973 and December 2004 at our institution, were identified and their medical records and diagnostic data reviewed. Results: Thirty seven patients identified (24 women), with a median age of 54 years (range 2-74). The most common symptom was dyspnea (51%), followed by embolism (24%) and cardiac murmurs (16%). The diagnosis was made by echocardiogram in 84% of patients. The mean tumor size was 4.9 ± 1.3 cm. The tumor was located in the left atrium in 83% of the patients, right atrium in 8% and left ventricle in 3%. Two patients had multiple tumors. Surgical approach was transeptal in 51%, left atriotomy in 22%, combined transeptal and roof of the left atrium in 19% and right atriotomy in 8%. The tumor and its attachment base were excised in one piece. There were two operative deaths and five late deaths. The mean follow-up was 11.5 years. The 5, 10, 15 and 20 years survival was 89%, 83%, 75% and 64%, respectively. Two patients had recurrence (5.4%), at 2 and 25 years after surgery, respectively, and the recurrence free survival at 10 and 25 years was 97% and 73%, respectively. Conclusions: Dyspnea was the most common symptom and echocardiogram the main diagnostic method. Surgical treatment was highly effective, with low mortality and recurrence rate, with good long term survival (Rev Med Chile 2008; 136: 287-95). (Key words: Echocardiography; Heart neoplasms; Myxoma)

Persistencia del estrés oxidativo postrasplante cardíaco: estudio comparativo entre pacientes con trasplante cardíaco y con insuficiencia cardíaca crónica estable

Introduccion y objetivo Existe estres oxidativo en pacientes con insuficiencia cardiaca cronica (ICC). El trasplante cardiaco, alternativa terapeutica importante en estos pacientes, podria disminuir el estres oxidativo al mejorar la funcion cardiaca. Nuestro objetivo fue evaluar el estres oxidativo postrasplante cardiaco. Pacientes y metodo Fueron estudiados 3 grupos experimentales: a) trasplantados cardiacos, sin evidencia de rechazo (n = 11); b) pacientes con ICC capacidad funcional III de la NYHA (n = 19), y c) sujetos controles sanos (n = 14). El estres oxidativo se evaluo determinando valores plasmaticos de malondialdehido (MDA), y actividades de glutation peroxidasa (GSH-Px), catalasa (CAT) y superoxido dismutasa (SOD). Resultados Las caracteristicas demograficas fueron similares entre los grupos. El tiempo postrasplante fue 20,0 ± 4,8 meses. Los valores de MDA en trasplantados y con ICC fueron significativamente mayores que en sujetos normales (3,35 ± 0,8; 3,27 ± 1,7, y 0,90 ± 0,3 µM, respectivamente). La actividad de GSH-Px aumento en trasplantados respecto al grupo control (0,40 ± 0,07 y 0,33 ± 0,05 U/g Hb, respectivamente). La actividad de SOD fue menor en trasplantados respecto al grupo control ICC (0,44 ± 0,1 frente a 0,87 ± 0,6 U/mg Hb). No hubo diferencias en las actividades de CAT entre trasplantados y pacientes con ICC. Conclusion Los pacientes sometidos a trasplante cardiaco tienen un aumento del estres oxidativo, evidenciado por una elevacion del MDA y por una disminucion de la actividad de SOD, a pesar de una mayor actividad de GSH-Px. Este aumento del estres oxidativo fue similar al encontrado en pacientes con ICC estable CF III de la NYHA, y se observo en ausencia de episodios reconocidos de infeccion o rechazo.

Operación de Fontan: resultados inmediatos y a mediano plazo con anastomosis cavopulmonar total

Background: During the last five years, 65 patients with univentricular heart have been treated surgically in our institution, according to a protocol of staged operations that have been previously reported. Aim: To evaluate the early and mid-term outcome of those patients that have completed their staging protocol by means of a Fontan procedure. Patients and Methods: Between April 1996 and June 2001, 23 patients (age 16 to 223 months) underwent a Fontan procedure, 15 with an intracardiac lateral tunnel technique and 8 with an extracardiac conduit. A retrospective review of their clinical, surgical, echocardiographic, angiographic and hemodynamic data was performed, trying to identify risk factors for both mortality and functional capacity (FC). Follow up was complete in all survivors. Results: Three patients died early after surgery (13.04%). Excessive pulmonary blood flow was a risk factor for early death (p= 0.03). One patient died at 14 months. Follow up was 29.9 months (1-63). For those who survived the operation, five years survival was 93.3%. The majority of patients are in FC I or II, with no related risk factors. Conclusions: Our current results are comparable with those of larger series. Patients reach good FC and mid-term survival, irrespective of type of single ventricle or the surgical strategy (Rev Med Chile 2002; 130: 1217-26).

Factores determinantes en la aparición de fibrilación auricular post-cirugía de revascularización miocárdica: Un estudio prospectivo

Background: Atrial fibrillation (AF) is a relevant complication after coronary artery bypass grafting (CABG). However there is controversy regarding possible contributing factors. Aim: To study the incidence of AF, its risk factors and its repercussion on hospital stay and charges, in patients undergoing CABG. Material and methods: We prospectively collected information from all patients undergoing CABG in our institution, including demographic, surgical and laboratory variables. Exclusion criteria were chronic AF, recent onset AF and patients who needed additional surgical procedures. The primary endpoint was the incidence of AF during the hospital stay. Secondary endpoints were hospital length of stay and hospital charges. Results: We included 250 patients aged 62±9 years (199 males) in the analysis. Incidence of AF was 22% (54 patients). Multivariable analysis showed that age (Odds Ratio (OR) =1.10), previous CABG (OR =9.39), previous use of ACE inhibitors (OR =3.28) and aortic clamp >57 minutes (OR =3.97) were significantly associated with an increased risk of postoperative AF. Previous use of beta-blockers was associated with risk reduction (OR =0.43). Patients who developed AF had a longer hospital stay (p <0.001) and higher hospital charges (p =0.003). Conclusion: AF is a frequent complication in patients undergoing CABG. Risk factors are age, time of aortic clamp, previous CABG and ACE inhibitors. Beta-blockers may prevent its occurrence. Furthermore, AF has a negative impact on both hospital stay and hospital charges (Rev Med Chile 2007; 135: 967-74).

Cirugía valvular reparadora en endocarditis infecciosa

Background: Valve replacement has been the treatment of choice for patients with valvular complications of infectious endocarditis (IE). However, excellent results with valve repair allowed it to become a new therapeutic alternative for these patients. Aim: To evaluate the results of valve repair in patients with valvular complications of IE. Patients and Methods: From January 1991 to December 2000, 14 patients with valvular complications of IE underwent valve repair. Mean age was 37.9 ± 14.9. Results: New York Heart Association (NYHA) class was 2.8 ± 0.9. IE was located in the aortic in 6 (42%), in the mitral valve in 4 (29%) and in both valves in 4 cases (29%). Surgical indication was hemodynamic in 50% of the cases, echocardiographic in 29% and septic in 21%. Five aortic valves were bicuspid, 3 mitral valves were myxomatous and the rest were normal. The most common septic lesions were vegetations and leaflet perforations. A total of 23 aortic and 21 mitral valve repair procedures were performed. There were no deaths. Only 1 patient had a surgical complication (renal failure and prolonged mechanical ventilation). Follow-up was 100% complete. There was not late mortality. One patient with bone marrow aplasia required reoperation for a new episode of IE 19 months later. At the end of the follow-up NYHA class was 1.3 ± 0.6 and echocardiography showed a mild or absence of valve regurgitation in most patients. Conclusions: Valve repair surgery in IE has good results, with advantages over valve replacement (Rev Med Chile 2004; 132: 307-15). (Key Words: Cardiovascular surgical procedures; Endocarditis, bacterial; Surgical procedures, operative)

Tratamiento endovascular del trauma de aorta descendente

Mortality of traumatic aortic lesions is over 80%. Agroup of those who survive, develop a chronic pseudo aneurism, usually asymptomatic, that isdetected during imaging studies. Since conventional surgical treatment of traumatic aorticlesions has a great mortality, endovascular treatment has been used as an alternative treatmentin the last decade.

Cirugía paliativa mediante operación de Norwood en distintas formas de corazón univentricular: resultados quirúrgicos inmediatos

: Norwood procedure is used as the first stage in thepalliative treatment of the hypoplastic heart syndrome and can be used, with some technicalmodifications, in other forms of univentricular heart with aortic stenosis or hypoplasia. Thesepatients have a high mortality (50%), derived from the procedure itself and from their abnor-mal physiological status.