EComment. The prognostic role of the MELD score in cardiac surgery patients with cirrhosis

Abstract

We read with great interest the recent article from Lopez-Delgado and colleagues [1], addressing the very relevant issue of risk prediction of short-term outcome in cirrhotic patients undergoing cardiac surgery. However, we believe that some aspects of the article require further comment. The Model for End-stage Liver Disease (MELD) score has gained increased popularity over recent years in predicting the risk of mortality in patients with liver cirrhosis undergoing cardiac surgery. We agree that the MELD score improves prognostic assessment of those cirrhotic patients who are at an extraordinary high risk for major postoperative complications and in-hospital mortality after conventional cardiac surgery. Crucially, the mean preoperative MELD score is usually significantly lower among survivors compared to non-survivors. In a recent article [2], our group showed that in 57 cirrhotic patients, those with a MELD score of 13.5 points or higher had a significantly higher risk of dying within 30 days of cardiac surgery (mortality: 56%) than patients with a MELD score less than 13.5 (mortality: 9%) with a sensitivity of 82.0% and a specificity of 78.5%. With an even better discriminative power, Lopez-Delgado and colleagues [1] demonstrate the prognostic strength of the MELD score for in-hospital mortality with a cut-off value of 18.5. In this study of 58 patients who underwent cardiac surgery, predominantly for isolated primary valve replacement (71%), the overall mortality rate was 12% at 4 months. This figure consisted exclusively of in-hospital mortality, without any further documentation of deaths in the early period after discharge from the cardiac surgery clinic. These promising results are inconsistent with our data [2] and those of another recently published retrospective study of 109 such patients from Germany [3], in which the overall in-hospital mortality was found to be 29.8% and 26%, respectively. Unfortunately, the work of Lopez-Delgado and colleagues [1] focused only on short-term outcome, with a follow-up of just four months. Therefore, their work contributes no additional knowledge to this field, as they simply did not incorporate a long enough follow-up period to enable comparison with other studies in this area. In addition, the authors state that,“ … the MELD values are higher than in previous studies, which is likely due to the high number of patients awaiting liver transplantation … ” It would be interesting to know if and how many of these cirrhotic patients indeed underwent liver transplantation after successful cardiac surgery, and particularly whether this institutional strategy could have influenced short-term survival. Clarity on this specific issue and a better longitudinal data collection would add important information to the study. However, irrespective of early outcomes achieved, it is clear that 1-year survival rate drops significantly in cirrhotic patients considered to be at elevated operative risk. In our study [2] and according to the MELD score, 1-year survival was 23.8% with MELD score > 13.5 as compared to 74.6% with MELD score < 13.5. Roughly 75% of our high-risk cirrhotic population died after conventional cardiac surgery, despite adherence to strict preventive and postoperative management strategies, and expert consultation before and up to one year after surgery. Disappointingly, cardiac surgery in such individuals is performed before liver transplantation candidacy and often on an emergency basis with little if any impact on long-term survival. Although liver cirrhosis alone is not considered a contraindication for surgery, cirrhotic patients with a high preoperative MELD score, in whom life expectancy per se is also limited by non-cardiac comorbidities, should be treated with caution. In this sub-group of cirrhotic patients, we believe that conventional cardiac surgery should not be performed. Conflict of interest: none declared