Device Increases Survival Rates for Children with Heart Failure

A ventricular assist device specifically designed for children produced significantly higher survival rates for children with severe heart failure who were waiting for cardiac transplants compared with extracorporeal membrane oxygenation (ECMO), according to the recent findings of a prospective study. The results of the multicenter study were reported in the New England Journal of Medicine [2012;367(6):532-541].

Currently, there are few options available for children who need mechanical circulatory support as they wait for cardiac transplantation and as a result, according to the authors of this latest study, there is a high death rate for children on cardiac transplant waiting lists. At present, many small children undergo ECMO; however, the effective period of support is usually only about 10 to 20 days. The EXCOR^® Pediatric Ventricular Assist Device (VAD) offers another option for children needing mechanical circulatory support. This device, which is a paracorporeal, pneumatically driven, pulsatile-flow device, is available in a variety of sizes to fit the needs of children.

Researchers in this prospective study wanted to evaluate the effectiveness of the VAD in serving as a bridge to heart transplantation by comparing children who underwent implantation with the device to a historical control group of children who had received support with ECMO.

During the study, which took place in 17 pediatric cardiac centers in the United States and Canada, 48 children £16 years of age, who weighed between 3 kg and 60 kg with 2-ventricle circulation and severe heart failure, underwent surgical implantation with an EXCOR Pediatric VAD. The children who received the VAD were divided into 2 cohorts based on their body surface area, with cohort 1 (n=24) comprising of those participants with a body surface area of <0.7 m² and cohort 2 (n=24) consisting of those participants with a body surface area of at least 0.7m² but <1.5 m².

Researchers compared these data with a historical control group of children receiving circulatory support with EMCO by using data from the Extracorporeal Life Support Organization (ELSO) registry. Using a propensity-score analysis, researchers said they matched each participant receiving a VAD with 2 children who had received support with EMCO.

The primary efficacy end point of the study differed depending on the treatment method. For those patients receiving a VAD, the primary end point was time to death or weaning from the device with an unacceptable neurological outcome, such as coma, or profound sensory, motor, language or cognitive impairment. For those patients in the historical control group, the primary end point was time to death.

Based on the results of the trial, researchers found that the survival rates were significantly higher for patients who had received the VAD than for those in the EMCO control group. They reported that in cohort 1, the median survival time had not been reached at 174 days, while the matched ECMO group had a median survival time of 13 days (P<.001 by the log-rank test). In addition, in cohort 2, the median survival time was 144 days compared with 10 days in the matched ECMO group (P<.001).

Researchers also assessed adverse events that occurred during the trial and found that those patients in the combination therapy group experienced serious adverse events during treatment. According to the data, 42% of participants in cohort 1 and 50% of participants in cohort 2 had major bleeding; 63% of those in cohort 1 and 50% of those in cohort 2 had infection; and 29% of those in cohort 1 and 29% in cohort 2 had a stroke.

The authors of the study cited the lack of randomization as an important limitation of the study.