Santiago Flórez

Comparative study of single-dose and 24-hour multiple-dose antibiotic prophylaxis for cardiac surgery

OBJECTIVE Use of single-dose antibiotic prophylaxis is associated with reduced antibiotic resistance, lower costs, and fewer problems with drug toxicity and superinfections. We tested the hypothesis that single doses of cefazolin are as effective as a 24-hour regimen of cefazolin in preventing surgical site infections in adults undergoing cardiac procedures. METHODS This random, prospective, clinical study included 838 adult patients undergoing elective coronary artery bypass grafting, valve operations, or both. These patients were randomly given a single dose of cefazolin (2 g) or a 24-hour treatment (2-g initial dose, followed by 1 g every 8 hours). Investigators blinded to the drug regimen diagnosed wound infections according to Centers for Disease Control and Prevention criteria. Patient clinical and demographic characteristics were noted, with follow-up for 12 postoperative months. The primary objective was to compare the incidence of surgical infections between groups up to 12 months postoperatively. RESULTS A total of 419 patients received single-dose cefazolin, and another 419 received the 24-hour treatment. Surgical site infection occurred in 35 (8.3%) patients receiving single doses and 15 (3.6%) patients administered the 24-hour treatment (P = .004). We identified no differences between groups for mortality or duration of hospitalization (preoperative hospitalization, intensive care unit stay, and hospitalization after surgical intervention). The microorganisms isolated showed a similar distribution in both groups. The germs isolated were gram-positive cocci in 86% of the surgical site infections. CONCLUSIONS Single-dose cefazolin used as antibiotic prophylaxis in cardiac surgery is associated with a higher surgical site infection rate than the 24-hour, multiple-dose cefazolin regimen.

Isolated Right-Sided Valvular Endocarditis in Non-Intravenous Drug Users

INTRODUCTION AND OBJECTIVES Characteristics of isolated right-sided endocarditis in patients without a pacemaker and who are not intravenous drug users (IVDU) are poorly understood. The aim of this study was to investigate the current frequency of this entity and describe its clinical, microbiological, echocardiographic and prognostic profile. METHODS We have prospectively analyzed 17 consecutive cases of isolated right-sided endocarditis in non-IVDU who did not have a pacemaker, out of a total of 583 consecutive episodes of endocarditis (2.9%). RESULTS Mean age was 38+/-15 years; 11 of the 17 patients were men. Almost half of the patients had at least one predisposing disease. An intravascular catheter was the most frequent port of entry (35%). The most common signs and symptoms on admission were fever, dyspnea, septic pulmonary embolisms, pleural effusion and right-sided heart failure. The most frequent microorganism was Staphylococcus aureus (41%). In most cases (82%) the infection was located in the tricuspid valve. Recurrent pulmonary embolisms were the most frequent complication and the main cause for surgery, which was needed in 5 patients (29%). Two patients died during hospitalization (12%), both from septic shock. During follow-up one patient died of unknown causes 1 month after discharge, and other relapsed 3 months after discharge. CONCLUSIONS Isolated right-sided endocarditis should be included in the differential diagnosis of patients with febrile syndrome, respiratory symptoms and predisposing disease, even when they do not have a pacemaker and are not IVDU. The presence of intravascular catheters and Staphylococcus bacteriemia should heighten suspicion of endocarditis.

Building a New Annulus: A Technique for Mitral Valve Replacement in Heavily Calcified Annulus

We describe the rationale, methodology, and our preliminary experience with a new surgical technique for mitral valve replacement in patients with severe calcification of the mitral annulus in which the conventional techniques can not be applied. In contrast with other procedures published in the literature for these patients, in which the placement of the prosthesis is supra-annular, we plicate both mitral leaflets and the atrial wall creating a new annulus that allows the intra-annular placement of the prosthesis.

Hemodynamic and cerebral repercussions arising from surgical interruption of the superior vena cava: Experimental model

This study was designed to analyze the hemodynamic and cerebral repercussions arising from the surgical interruption of the superior vena cava. The experiments were carried out in 12 mongrel dogs under two different conditions: with shunt (group A, n = 6) and without the installation of a shunt (group B, n = 6). The period of occlusion was 35 minutes. The right atrium pressure, pulmonary arterial pressure, and aortic pressure are not significantly modified in the two groups. The intracranial pressure had an important correlation with the central venous pressure (r2 = 0.8572). In group B, the intracranial pressure had a sharp increase between the basal period (6.9 +/- 1.47 mm Hg) and the clamping superior vena cava (17.2 +/- 1.05 mm Hg), accentuated with the interruption of the azygous vein (32.2 +/- 0.7 mm Hg). In group A, the use of a shunt avoided this alteration during clamping of the superior vena cava (6.8 +/- 2.0 mm Hg) and the azygous vein (8.0 +/- 2.24 mm Hg). However, after removal of the clamps in group B, an elevated residual intracranial pressure was observed (21.1 +/- 3.33 mm Hg) in contrast to the central venous pressure, which returned to the basal values (4.4 +/- 0.7 mm Hg). The biomechanic findings of the volume-pressure curves (with Miller and Marmarou-Shapiro tests) and the cerebral necropsy showed brain damage in group B, without the shunt. Three animals had areas of hemorrhagic infarction. Histologic study demonstrated signs the incipient vasogenic edema. In group A, all findings were compatible with the normal. In conclusion, these results suggest the importance of shunting the blood in those cases of a nonobstructed superior vena cava because the clamping and reconstruction produce hemodynamic compromise and brain damage.

The inflammatory response to colloids and crystalloids used for pump priming during cardiopulmonary bypass.

Background: Systemic inflammatory response frequently occurs after coronary artery bypass surgery and is strongly correlated with the risk of postoperative morbidity and mortality. This study tests the hypothesis that the priming of the extracorporeal circuit with colloid solutions results in less inflammation in patients undergoing cardiac surgery than priming with crystalloid solutions.

El polimorfismo R753Q del toll-like receptor 2 se asocia a un aumento en el riesgo de sufrir endocarditis infecciosa

The ability to respond to the ligands of toll-like receptors (TLR) could be affected by single nucleotide polymorphisms in TLR codifying genes. The influence of the polymorphisms TLR2 (R753Q, R677W), TLR4 (D299G, T399I) and CD14 (C-159T) was consecutively studied in 65 patients with infective endocarditis. The control group (n=66) consisted of healthy volunteers. All the polymorphisms were genotyped by means of restriction analysis after their amplification. An association between endocarditis and variants of TLR2 R753Q (P <.001) was observed, but no association with other polymorphisms was found. The TLR2 R753Q co-dominant (odds ratio=13.33), recessive (odds ratio=9.12) and dominant (odds ratio=3.65) genotypes showed a positive association with the infective endocarditis phenotype. The polymorphism TLR2 R753Q was associated with a greater susceptibility towards the development of infective endocarditis. Further studies are required to validate these results and identify other genetic risk factors.

Cardiac Surgery With Extracorporeal Circulation in Cancer Patients: Influence on Surgical Morbidity and Mortality, and on Survival

INTRODUCTION AND OBJECTIVES Morbimortality related to cardiac surgery may be superior in patients with malignant neoplastic disease. Inflammatory phenomena and immunologic changes secondary to extracorporeal circulation use can also increase tumor recurrence. We evaluate characteristics and results of cardiac surgery in our neoplastic patients. METHODS Out of 2146 consecutive patients who underwent cardiac surgery with extracorporeal circulation, 89 (4.2%) had been previously affected by cancer. Cancer was active (recent diagnosis or under treatment) in 33 patients (group A) and 56 (group B) were in remission. Both groups were matched with 165 patients with no tumor, according to age, gender, type of surgery, and comorbidity (group C). We retrospectively evaluated incremental risk factors for surgical morbimortality, survival and tumor recurrence. RESULTS Median interval between cancer diagnosis and surgery was 60 months and mortality and morbidity were 4.5% and 36%, respectively, vs 5,4% and 32,7% in group C. During follow-up, 12 patients died (8 due to cancer), 16 suffered cancer recurrence and 2 new tumors were diagnosed. Statistical analysis did not permit us to identify any incremental risk factor for mortality. Postoperative morbidity was increased in case of preoperative renal failure. During follow-up, survival was significantly decreased in group A, in case of preoperative left ventricular dysfunction or pulmonary obstructive disease, and when interval between cancer diagnosis and cardiac surgery was under 2 years. CONCLUSIONS We have not observed an increase in cardiac surgery morbimortality in cancer patients. Anyway, survival is decreased in case of active or recently diagnosed cancer.

Risk Factors for Mediastinitis and Endocarditis after Cardiac Surgery

A prospective open-cohort study was performed in 838 adults undergoing coronary revascularization or valve surgery to define the risk factors for development of surgical site infections. Patients diagnosed with mediastinitis or endocarditis during follow-up were compared with patients with no such infection. After 1 year of follow-up, 22 (2.6%) patients had developed mediastinitis or endocarditis. No preoperative or intraoperative variables were identified as risk factors. By multivariate analysis of postoperative variables, respiratory insufficiency, microorganisms in blood cultures, and intensive care unit stay were independent risk factors for the development of these complications. The type of antibiotic prophylaxis had no influence on the incidence of organ or space infections after cardiac surgery.

Cirugía cardiaca con circulación extracorpórea en pacientes oncológicos: influencia en la morbimortalidad quirúrgica y la supervivencia

Introduccion y objetivos La morbimortalidad de la cirugia cardiaca parece ser mayor en los pacientes neoplasicos. Los fenomenos inflamatorios y las reacciones inmunitarias secundarias a la circulacion extracorporea pueden favorecer la recidiva tumoral. Evaluamos las caracteristicas y los resultados de la cirugia cardiaca en nuestros pacientes oncologicos. Metodos De 2.146 pacientes consecutivos sometidos a circulacion extracorporea, 89 (4,2%) presentaban una neoplasia. El cancer estaba activo (recientemente diagnosticado o en tratamiento) en 33 pacientes (grupo A) y en remision completa en 56 (grupo B). Se pareo ambos grupos con 165 pacientes sin tumor similares en edad, sexo, tipo de cirugia y comorbilidad (grupo C). Evaluamos retrospectivamente los factores de riesgo de morbimortalidad quirurgica, supervivencia y recidiva tumoral. Resultados La mediana del intervalo entre diagnostico del cancer y cirugia fue de 60 meses, con mortalidad y morbilidad hospitalarias del 4,5 y el 36%, respectivamente, frente al 5,4 y el 32,7% en el grupo C. Durante el seguimiento, fallecieron 12 pacientes (8 por causa tumoral), 16 sufrieron recidiva y 2, tumores nuevos. El analisis estadistico no permitio identificar ningun factor de riesgo de mortalidad. La morbilidad postoperatoria aumento en pacientes con insuficiencia renal. Durante el seguimiento, la supervivencia disminuyo significativamente en el grupo A en caso de disfuncion ventricular izquierda preoperatoria y enfermedad pulmonar obstructiva cronica y cuando el intervalo entre diagnostico de cancer y cirugia fue Conclusiones No hemos observado un incremento en la morbimortalidad de la cirugia cardiaca en pacientes oncologicos. No obstante, la supervivencia disminuye en neoplasias activas o de diagnostico reciente.

Efecto de la simvastatina en la concentración de las proteínas de fase aguda después de la cirugía cardíaca

Fundamento y objetivo Existe informacion contradictoria referente a que los efectos pleiotropicos de las estatinas mejoran la morbimortalidad de las intervenciones con circulacion extracorporea, ya que reducen las concentraciones plasmaticas de proteinas de fase aguda. Pacientes y metodo Se ha realizado un estudio prospectivo y aleatorizado que incluyo a 44 pacientes a los que se efectuo derivacion aortocoronaria con circulacion extracorporea. Se dividieron en 2 grupos: A (n = 22), formado por pacientes que tomaron simvastatina, y B (n = 22), que fue el grupo control. Se determinaron las concentraciones plasmaticas de proteinas de fase aguda (interleucina 6, fraccion C4 del complemento y proteina C reactiva). Resultados No se observaron diferencias significativas entre ambos grupos en las concentraciones de proteinas de fase aguda ni en las complicaciones postoperatorias. En ambos grupos, las concentraciones maximas de interleucina 6 se observaron a las 6 h de la cirugia y las de proteina C reactiva a las 48 h. Las concentraciones de C4 descendieron al inicio de la derivacion cardiopulmonar y volvieron a la normalidad a las 48 h. Conclusiones La administracion de simvastatina a pacientes intervenidos de revascularizacion miocardica con circulacion extracorporea no modifica las concentraciones plasmaticas de proteinas de fase aguda.