Highly Sensitized Patient (HSP) Program
Highly Sensitized Patient (HSP) Program Introduction
The Highly Sensitized Patient (HSP) Program was established by Canadian Blood Services in collaboration with provincial and territorial governments and organ donation and transplantation programs around the country to increase transplant opportunities for patients needing very specific matches from deceased kidney donors. Through the HSP Program, this group of patients now has access to a larger national donor pool, increasing the chance of a match. Prior to HSP, kidneys from deceased donors stayed within the province of origin – now, when a deceased donor anywhere in Canada has two eligible kidneys, one kidney is provided through the CTR to the HSP program for matching to potential recipients across the country. Kidneys are shared between provinces using the Canadian Transplant Registry (CTR), which tracks all HSP matches, offers and transplants.
The implementation of this national program began in October 2013 and by November 2014 all provinces and territories had joined the HSP Program.
- Highly sensitized patients are people who critically need an organ transplant, but because their immune system is sensitized, very few available donors can provide a match.
- Immune system sensitization may occur from blood transfusions, previous transplants or pregnancies, which is why many highly-sensitized patients are women.
- Highly sensitized patients wait much longer on average for a kidney transplant and have a greater chance of becoming more ill or dying while they wait.
HSP Program Policy
The program has formalized national policies approved by all provinces and territories. Canadian Blood Services and its advisory committees* work in collaboration with donation and transplantation programs to evaluate and improve HSP Program policies. The program life cycle is presented below:
The list of policies required to facilitate the HSP Program are presented below:
1) Recipient Eligibility Criteria
- Defines the eligibility requirements for potential transplant recipients to participate
2) Matching & Ranking
- Outlines the matching algorithm rules used to identify and rank highly sensitized patients who are potential matches to an available organ
3) Requirement to Offer
- Describes the mandatory procedure for program participants with respect to making offers of donated organs
4) Inter-provincial Balancing Protocol
- Promotes equitable sharing of hearts by establishing thresholds to limit the number of imports and exports of hearts by any one province
How the HSP operates
There are four tiers of matching and ranking that the HSP algorithm performs to develop a final listing of potential HSP recipients who are compatible with an available deceased donor organ.
• Step One: Matching for compatible blood group, using the same compatibility rules as any patient requiring a blood transfusion.
• Step Two: Screen for HLA compatibility to avoid donor specific antibodies for patients identified as blood group compatible.
• Step Three: Further screening of donor suitability based on individual attributes of the potential recipient/donor or the clinical direction of potential receiving local programs.
• Step Four: If more than one potential recipient is identified, the HSP algorithm uses agreed-upon policies to transparently prioritize recipients based on key medically and logistically relevant factors.
The allocation list of prioritized potential HSP recipients who are compatible is then presented to the Organ Donation Organization (ODO) coordinator from the CTR. The ODO coordinator uses the allocation list to make offers to potential recipients on the list, by rank. The potential recipient’s transplant team and HLA Laboratory assess the offer and a decision is made to accept or decline the offer. If accepted, the donor ODO and potential recipient’s ODO, transplant program and HLA Laboratory work collaboratively to recover the kidney, perform an actual crossmatch, transport the kidney, and transplant the kidney.
The HSP algorithm is part of Canadian Blood Services’ Canadian Transplant Registry, which is a web-based technology available 24/7 to Transplant Programs, Organ Donation Organizations (ODOs) and Human Leukocyte Antigen (HLA) Laboratories.
Through the HSP program, Canadian Blood Services helps simplify and accelerate organ sharing across the country 24/7 and in real-time by:
- Listing highly sensitized patients waiting for a match in the Canadian Transplant Registry
- Managing a detailed list of clinical and immune data to allow for precise donor matching
- Using the HSP algorithm in the Canadian Transplant Registry to match donors to sensitized patients across Canada
- Using the Canadian Transplant Registry to track organ sharing between provinces
- Reporting on and sharing national program performance data so organ donation and transplantation in Canada can continue to improve
*Kidney Transplant Advisory Committee, National HLA Advisory Committee, Donation and Transplantation Administrators Advisory Committee and Organ Donation and Transplantation Expert Advisory Committee