Carlos Nojek

Impaired anti-platelet effect of aspirin, inflammation and platelet turnover in cardiac surgery

A reduced platelet inhibitory response to acetyl salicylic acid (ASA) has been associated with an increased risk of graft thrombotic occlusion after coronary artery bypass grafting (CABG). We performed a prospective, observational study of 18 patients on 100 mg/day ASA before and after CABG. We assessed antiplatelet response to ASA and its relationship with platelet turnover, inflammatory markers, and soluble thrombomodulin (sTM) levels. All patients showed optimal response to ASA preoperatively but had higher values during follow-up. Platelet aggregation and platelet count in the perioperative period were significantly associated (P=0.05). Platelet turnover was defined as the average daily turnover (ADTO). The lowest inhibitory value (28% of patients > or =6 Omega) was recorded at the same time of the highest platelet turnover (>10% daily in 77.77% of patients), one week after CABG. ADTO >10% was associated with an increased risk of platelet aggregation > or =6 Omega. Levels of sTM were significantly higher one week after CABG (median 13 vs. 3 ng/ml preoperatively, P=0.0011). There is a transient impairment in ASA antiplatelet effect after CABG related to an increased platelet turnover caused by the inflammatory process. This could be responsible for the high risk of occlusive thrombosis.

Cirugía cardíaca neonatal: análisis comparativo de resultados quirúrgicos según el método RACHS-1 de estratificación del riesgo

INTRODUCTION The RACHS-1 method (Risk Adjustment for Congenital Heart Surgery) is widely used to predict mortality and risk adjustment in pediatric cardiovascular surgery and constitutes a valid tool to compare results among different health centers. OBJECTIVE To analyze if the mortality observed in the neonatal group is related to age and/or the risk stratification according to RACHS-1. METHODS From March 2001 to May 2008 we operated on 751 consecutive patients: 160 neonates (0-30 days), 309 infants (31 days-1 year) and 282 olders (1-18 years). Patients in each group were analyzed according to age, RACHS-1, and mortality. We used a logistic regression in which the mortality was the dependent variable and the age and RACHS-1 the independent variables. RESULTS The total crude mortality was 4.3%, the neonatal 9.2%. We observed a significant statistical difference of RACHS-1 distribution according to age (chi(2)= 219, p< 0.0001). Logistic analysis showed no statistical difference of mortality (p> 0.05) in the age groups compared to RACHS-1. Furthermore, RACHS-1 is a most powerful mortality predictor (p< 0.001) while age is not (p= 0.8). Using our unit one of RACHS-1 as control group, the odds ratio of the different ages were 2.1 (CI 95%: 1.6-2.7) for each RACHS group. CONCLUSIONS The age of surgery was not an independent risk factor as to mortality. The RACHS-1 method appeared as a powerful risk factor predictor of mortality; no differences were found in the age groups when classified by RACHS -1.

Increase in elderly patients undergoing cardiac surgery. A worldwide phenomenon

We read with great interest the article by Saito et al. w1x, and we absolutely agree with their findings; in particular, the importance of using a local risk stratification system for preoperative assessment of cardiac surgical patients. In Argentina, as well as in other countries, the ageing population is indeed an issue for several reasons. For instance, as physicians we face an increasing number of elderly patients suffering from preoperative comorbidities, a situation especially common among those undergoing cardiac surgery w2x. In this regard, it is worth mentioning that our risk model initially had 2.69% of the study population 80 years old or more. However, 10 years later the same age group represented 5.24% of the whole sample size (P-0.001). As stated by Saito et al. w1x, the number of comorbidities increased in our validating population w2x. We strongly agree with the development of epidemiological studies in different parts of the world, such as the one published by Saito et al., since they provide good insight into the local population characteristics and risks models, clearly different from those found in Latin America w2x, Asia w1x, Europe w3x or North America w4x. The first Latin-American risk stratification system for cardiac surgery: can be used as a graphic pocket-card score.