Study Population
From 2011 to 2017, a total of 43,077,206 discharge records comprised the
NIS for the US adult population (age 18 years or above), corresponding
to a national estimate of 214,107,782 hospitalizations across the
country. We identified all patients aged 18 years or older undergoing
LVAD implantation using ICD-9-PCS code 37.66 and ICD-10-PCS code 02HA0QZ
in any procedure field. Our final study cohort comprised 5,131 patients
undergoing LVAD implantation, corresponding to a weighted estimate of
25,503 overall LVAD implantations during this time period. This estimate
was calculated by using discharge weights provided with the NIS files.
The study population was reflective of the one device era—the
continuous flow (CF) device based on the US Food and Drug Administration
approval of CF devices in 2008. ICD-9-CM/PCS and ICD-10-CM/PCS coding
for comorbidities, post-LVAD complications and other procedures is
listed in Table I in the Data Supplement.