Complication patterns in patients undergoing venoarterial extracorporeal membrane oxygenation in intensive care unit: Multiple correspondence analysis and hierarchical ascendant classification

Abstract

Background: Treatment by venoarterial extracorporeal membrane oxygenation (VA-ECMO) is widely used today, even though it is associated with high risks of complications and death. While studies have focused on the relationship between some of these complications and the risk of death, the relationship between different complications has never been specifically examined, despite the fact that the occurrence of one complication is known to favor the occurrence of others. Our objective was to describe the relationship between complications in patients undergoing VA-ECMO in intensive care unit (ICU) and to identify, if possible, patterns of patients according to complications.

Methods and findings: As part of a retrospective cohort study, we conducted a multiple correspondence analysis followed by a hierarchical ascendant classification in order to identify patterns of patients according to main complications (sepsis, thromboembolic event, major transfusion, major bleeding, renal replacement therapy) and in-ICU death. Our cohort of 145 patients presented an in-ICU mortality rate of 50.3%. Morbidity was high, with 36.5% of patients presenting three or more of the five complications studied. Multiple correspondence analysis revealed a cumulative inertia of 76.9% for the first three dimensions. Complications were clustered together and clustered close to death, prompting the identification of four patterns of patients according to complications, including one with no complications.

Conclusions: Our study, based on a large cohort of patients undergoing VA-ECMO in ICU and presenting a mortality rate comparable to that reported in the literature, identified numerous and often interrelated complications. Multiple correspondence analysis and hierarchical ascendant classification yielded clusters of patients and highlighted specific links between some of the complications studied. Further research should be conducted in this area.

Fig 1. Multiple correspondence analysis: Variable plot for dimensions 1 and 2.

Active modalities are in red and illustrative modalities are in green. RRT: Renal replacement therapy. This figure represents the two-dimensional (dimensions 1 and 2) graph generated from the estimated model, which showed the importance of the different complication variables and their impact on data distribution.

Fig 2. Multiple correspondence analysis: Variable plot for dimensions 1 and 3.

Active modalities are in red and illustrative modalities are in green. RRT: Renal replacement therapy. This figure represents the two-dimensional (dimensions 1 and 3) graph generated from the estimated model, which showed the importance of the different complication variables and their impact on data distribution.

Fig 3. Hierarchical ascending classification of patients: Dendrogram.

A dendrogram is a tree diagram which is used to illustrate the arrangement of clusters. Here, individuals are plotted on the abscissa axis. The black, red, green, and blue rectangles define the four clusters of patients. The graph in the top right corner represents the loss of inertia according to the different dimensions.

Fig 4. Hierarchical ascending classification of patients for dimensions 1 and 2.

A three-dimensional hierarchical tree and a factorial plane in which individuals are colored according to the cluster to which they belong. The classification of individuals yielded four clusters.