Bulletin 23-4

Standards Enforcement Discretion for Cardiac and Vascular Tissue: Total Ischemic Time, D5.400 and E2.520

July 24, 2023

This Bulletin seeks to clarify the total ischemic time for cardiac (C) and vascular (V) tissue within Standards for Tissue Banking, 14th Edition defined as “The time interval from asystole to subjecting tissue to disinfection solution. This is the sum of warm ischemic time and cold ischemic time.”

This issue being clarified involves current standards at D5.400 Time Limits for Postmortem Tissue Recovery and E2.520 Time Limits for Pre-processing, Processing and Preservation Phases.

D5.400 states, in part (bolded for emphasis): 
“Cardiac tissue and vascular tissue recovery and processing time limits (i.e., warm and cold ischemic time, disinfection time, and the perfusion time [specific to vascular tissues]) shall be established by each individual tissue bank; however, the following upper time limits for initiation of recovery of specific tissue types shall not be exceeded.”

E2.520 states, in part (bolded for emphasis): 
“Time limits and/or other valid process control end points or limits for the completion of each phase of processing and preservation shall be established and validated with reference to tissue quality. Additionally, a time limit and temperature for pre-processing quarantine storage that address tissue quality must be established and justified.

(C, V) Disinfection of cardiac and vascular tissue shall be accomplished via a time-specific, validated process (disinfection time). The total ischemic time shall not exceed 48 hours.”

E2.520 (C, V) potentially conflicts with D5.400 (C, V), in that E2.520 puts a limit on total ischemic time for disinfection to begin by 48 hours asystole for cardiac and vascular tissues. Warm ischemic time is established during the recovery of tissue from cadaveric donors. The time limit requirements for warm ischemic time must still be followed at the time of recovery and as described in D5.400. However, the length of cold ischemic time and thus total ischemic time can be established by each individual tissue bank as described in D5.400.

AATB consulted with all accredited establishments that process cardiac and vascular tissue and is now issuing this Bulletin to membership. The Association will exercise enforcement discretion for establishments affected by the 48-hour total ischemic time limit described in E2.520, until Standards are revised per current processes involving the Standards Committee, all-Council comment period and Board of Governors clearance.

Any potential Standards changes will not be contrary to FDA regulations, as there are currently no such requirements related to ischemic times in 21 CFR 1271.
 
If you have questions, please contact standards@aatb.org.