Table 1.

Study Definitions for BSI in LVAD Recipients

LVAD classification	Definition	Radiographic Criteria	Microbiologic Criteria	Operative or Histopathology Criteria
LVAD-associated	Episodes involving all “indeterminate” cases of BSI where infection of the internal surface of the LVAD is suspected but cannot be confirmed and after an alternative site of infection has been ruled out based on review of clinical findings, imaging studies, and microbiologic and laboratory data.	No definitive evidence of LVAD infection on imaging.	2 or more positive blood cultures of indeterminate source.	No inflammation or purulence of LVAD surrounding tissues.
LVAD-related	Episode of BSI arising from an infection on the external or internal surface of the device components including driveline, pocket, pump or cannula, and/or surrounding tissues	Any imaging modality showing fluid collection, gas, soft tissue inflammation, or increased uptake along the device components.	2 or more positive blood cultures± local swab from driveline, surgical site, or operative cultures demonstrating the same organism and susceptibility pattern.	Intraoperative evidence of tissue inflammation or purulence.
	Evidence of LVAD infection on physical examination (local inflammatory signs) or imaging.			Histopathology with acute or chronic inflammation and/or positive microbial stains.
Non-LVAD related	BSI episodes secondary to a confirmed alternative source of infection other than the internal or external surfaces of the LVAD or surrounding tissues (ie, pneumonia, catheter-related BSI, CIED infection).	No radiographic signs of LVAD infection. Imaging supporting infection elsewhere.	Blood cultures and local cultures with same organism and susceptibility pattern.	N/A

Abbreviations: BSI, bloodstream infection; CIED, cardiovascular implantable electronic device; LVAD, left ventricular assist device; N/A, not applicable.