In patients with obesity undergoing implantation with a left ventricular assist device (LVAD) as a bridge to transplantation, weight loss was possible, but not typical, according to research published in JACC: Heart Failure.

Investigators from New York-Presbyterian Hospital/Columbia University Medical Center and the Icahn School of Medicine at Mount Sinai in New York City sought to determine if post-LVAD implantation outcomes were worse in patients with obesity and if the implantation enabled patients to lose weight. As the researchers wrote, heart transplantation is not ideal for patients with morbid obesity; therefore, LVAD implantation can be a good alternative. However, little is known about implantation outcomes in these patients.

Using the United Network for Organ Sharing (UNOS) database, the researchers gathered information on patients who were bridged to transplantation with a continuous-flow LVAD between 2004 and 2014. In terms of body mass index (BMI), 2.2% of patients were classified as underweight, 25.5% as normal weight, 35.5% as overweight, 26.6% as class I obese, and 10.2% as class II obese or greater. The underweight group comprised more female patients with fewer ischemic cardiomyopathies; in addition, they had increased use of HVAD (Heartware; Framingham, MA), higher pulmonary vascular resistance, and higher glomerular filtration rates.


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The primary end point was delisting from the transplantation list while on device support and freedom from death, which was analyzed based on BMI group.

The researchers found no statistically significant difference in event-free survival between all groups while on LVAD support. There was also no significant difference between risk of death or delisting between BMI groups (P =.347), according to an unadjusted Cox-proportional hazards model.

However, compared with patients who had normal BMIs, patients with class II obesity or greater did have an increased risk of the primary end point (hazard ratio [HR]: 1.265; P =.054), but this did not reach statistical significance. In addition, there was no difference between BMI groups for risk of delisting from the transplantation list while on LVAD support or death, according to a competing risk analysis (P =.918 and P =.234, respectively).

When analyzing BMI as a continuous variable, the researchers also found no association between BMI and the primary end point on unadjusted or multivariable analysis (HR: 1.01; P =.14 and HR: 1.01; P =.11, respectively).

Regarding weight loss, only a small fraction (15.5%) of patients with class II obesity or greater were able to lose enough weight to decrease their BMI category at transplantation or delisting. Among those patients who were able to bridge to transplantation, BMI lowering while on LVAD support was also low (class I obesity: 10.1% and class II obesity or greater: 19.3%; P =.90).

At transplantation, patients with class I obesity had a 76% increased risk of death compared to patients with normal BMI (P =.001), followed by patients with class II obesity or greater, and finally, patients who were overweight.

The authors concluded that bridge to transplantation using LVADs should be carefully considered in patients with class II obesity or greater, and a multidisciplinary team (eg, nutritionists, cardiac physical therapists, and advance heart failure cardiologists) may be the best approach to help these patients lose weight.

“Otherwise, the waiting list will continue to expand with patients with a decreased chance of transplantation and have worse outcomes after transplantation,” they wrote.

Study Limitations

The researchers noted the retrospective nature of their study may have limited their findings, as well as certain data not being available via the UNOS database (eg, readmission rates, bleeding events, and serum albumin levels). There may have also been errors in patient weight reporting.

Disclosures: Dr Naka received consulting fees from Thoratec.

Reference

Clerkin KJ, Naka Y, Mancini DM, Colombo PC, Topkara VK. The impact of obesity on patients bridged to transplantation with continuous-flow left ventricular assist devices. JACC Heart Fail. 2016. doi:10.1016/j.jchf.2016.05.010.