Diseño y validación de la escala pronóstica cubana PREDICMED para estratificar el riesgo de mediastinitis postoperatoria / Design and validation of the Cuban prognostic scale PREDICMED to stratify the risk of postoperative mediastinitis

RESUMEN Introducción: La predicción de fenómenos en las ciencias médicas mediante escalas pronósticas constituye una herramienta valiosa en la actualidad y deben incluirse en el proceso de toma de decisiones. Pronosticar la mediastinitis postoperatoria permite disponer de recursos para su prevención. Objetivo: Construir una escala pronóstica para estratificar el riesgo de padecer mediastinitis postoperatoria. Método: Se realizó un estudio de casos y controles para los factores de riesgo de mediastinitis postoperatoria en el Cardiocentro Ernesto Guevara de Santa Clara, Cuba. Luego de la regresión logística se obtuvo el modelo y, a partir de este, se incluyeron y ponderaron los predictores para obtener la escala cubana pronóstica de mediastinitis postoperatoria: PREDICMED, que se validó por diversos métodos. Resultados: Esta escala se obtuvo con seis predictores y dos estratos de riesgo. Se analizó su rendimiento mediante ajuste, calibración y determinación de su poder discriminante, con buenos resultados. Se realizó validación interna por el método de división de datos y se comparó su capacidad en ambos subconjuntos (desarrollo y validación) sin diferencias. Se probó su buena validez de constructo, al no existir diferencias entre las probabilidades predichas y las observadas. También se analizó su validez de contenido mediante expertos. Por último, se determinó su validez de criterio al comparar con otra escala similar (MEDSCORE). PREDICMED presentó muy buena capacidad discriminatoria (área bajo la curva 0,962) y elevados valores de sensibilidad (84,62%) y especificidad (92,31%). Conclusiones: La escala pronóstica cubana PREDICMED, para estratificar el riesgo de mediastinitis postoperatoria, mostró buenos parámetros de validación y logró estratificar el riesgo en no alto y alto.

ABSTRACT Introduction: Phenomena prediction through prognostic scales is a valuable tool in medical sciences nowadays and it should be included in the decision-making process. Predicting postoperative mediastinitis allows to count on resources for its prevention. Objective: To build a prognostic scale to stratify the risk of suffering from postoperative mediastinitis. Method: A case-control study for the risk factors of postoperative mediastinitis was carried out at the Cardiocentro Ernesto Guevara from Santa Clara, Cuba. After the logistic regression, the model was obtained and from it, the predictors to obtain the Cuban prognostic scale of postoperative mediastinitis PREDICMED were included and weighted, which was validated through several methods. Results: This scale was obtained, counting on six predictors and two risk strata. Its performance was analyzed through adjustment, calibration and determination of its discriminating capacity, showing good results. Internal validation was carried out through the data division method and its capacity was compared in both subsets (development and validation) showing no differences. Its good construct validity was demonstrated, since there were no differences between the predicted and the observed probabilities. Its contents validity was also analyzed by experts. Finally, its criteria validity was determined when compared with another similar scale (Medscore). PREDICMED showed a very good discriminatory capacity (area under the curve 0.962) as well as high values of sensitivity (84.62%) and specificity (92.31%). Conclusions: The Cuban prognostic scale PREDICMED, to stratify the risk of postoperative mediastinitis showed good validation parameters and it was able to stratify the risk in not high and high.

Cuerpo extraño penetrante en el ventrículo izquierdo con evolución crónica inadvertida / Penetrating foreign body in the left ventricle with undetected chronic evolution

Penetrating cardiac trauma constitutes a serious threat for life. Less than the third part of all patients who suffer it arrives at the hospital alive, and half of them die. Most of the penetrating foreign bodies in the heart are metallic, and are frequently caused by firearms and rarely by self-injury. The accidental penetration is uncommon but inadvertent penetration is extremely rare. We present the case of a patient who suffered a closed-chest trauma and did not notice the penetration of a foreign body (copper wire fragment) in the heart. It remained lodged in the left ventricle for more than 3 months. This it is the only case reported in the literature where a strange body: a) crosses the free wall of the right ventricle, the right ventricular cavity, interventricular septum, and the mitral valve apparatus; b) occupies almost all the anteroposterior diameter of the heart, and c) did not produce acute or chronic bleeding.

Aneurisma gigante del apéndice auricular izquierdo / Huge aneurysm of the left atrial appendage

Atrial aneurysms are rare entities that can be congenital or acquired. Those involving the free wall or atrial appendage are even rarer. There are only 49 cases reported in the literature involving the left atrium and 8 in the right atrium until 2002. The most common clinical presentation is the appearance of recurring or incessant atrial arrhythmias. In addition, systemic embolization may occur as an imminent life-threatening event. We present the case of a female teenager who suffered from an embolic stroke during an atrial fibrillation. She had a giant aneurysm of the left atrial appendage that was successfully removed. Images from computed tomography, and of the aneurysm during the surgical intervention are shown.