Approach to planned reexposure to heparin for cardiac or vascular surgery, or for hemodialysis, in a patient with a previous history of HIT
| Considerations . | Comment . |
|---|---|
| Pre-UFH reexposure considerations | |
| 1. Does the patient have a strong indication for heparin, such as UFH for cardiac or vascular surgery, or UFH or LMWH for hemodialysis? | Numerous non-heparin anticoagulants are available for most other anticoagulant treatment or prophylaxis indications |
| 2. Did the previous episode of HIT occur more than 3 to 12 months ago? | The probability of a positive SRA is <5% by 3 months and negligible by 12 months, thus allowing for heparin reexposure in emergency settings (when there is no time for repeat testing) |
| 3. Do the serological studies indicate that the patient can receive UFH or LMWH safely? | EIA-negative or EIA-positive/SRA-negative (or HIPA-negative) status usually indicates that heparin administration is safe |
| Recommended intra- and postoperative management (cardiac or vascular surgery) | |
| 1. Give UFH (and protamine, if indicated) per usual dosing and practice | There is negligible risk of triggering acute HIT if platelet-activating antibodies are not present |
| 2. Postoperative anticoagulation, whether prophylactic or therapeutic dose, should be given with a non-heparin anticoagulant | Fondaparinux and danaparoid are viewed as nonheparin anticoagulants, although there is a low risk of clinically significant cross-reactivity with these drugs |
| 3. Perform platelet counts daily as inpatient, every 2 to 3 days as outpatient, until at least postoperative day 10 | Platelet count decrease in the first 4 postoperative days does not indicate HIT; however, any new decrease (>30%) in platelet count that begins in the postoperative day 5 to 10 window should be presumed HIT unless proven otherwise |
| Hemodialysis | |
| 1. Do the serological studies indicate that the patient can receive UFH or LMWH safely? | EIA-negative or EIA-positive/SRA-negative (or HIPA-negative) status indicates that heparin administration is safe |
| 2. Switch to UFH (or LMWH) for hemodialysis per usual practice at dialysis center | The intention (in the absence of HIT recurrence) is to continue heparin indefinitely |
| 3. Obtain pre- and postdialysis platelet counts and monitor for systemic (anaphylactoid) reactions (until approximately day 14 after the resumption of heparin) | Recurrent HIT could occur during the day 5 to 14 window after resuming heparin for hemodialysis; thus, monitoring for HIT recurrence during the day 5 to 14 time period is recommended |
| Considerations . | Comment . |
|---|---|
| Pre-UFH reexposure considerations | |
| 1. Does the patient have a strong indication for heparin, such as UFH for cardiac or vascular surgery, or UFH or LMWH for hemodialysis? | Numerous non-heparin anticoagulants are available for most other anticoagulant treatment or prophylaxis indications |
| 2. Did the previous episode of HIT occur more than 3 to 12 months ago? | The probability of a positive SRA is <5% by 3 months and negligible by 12 months, thus allowing for heparin reexposure in emergency settings (when there is no time for repeat testing) |
| 3. Do the serological studies indicate that the patient can receive UFH or LMWH safely? | EIA-negative or EIA-positive/SRA-negative (or HIPA-negative) status usually indicates that heparin administration is safe |
| Recommended intra- and postoperative management (cardiac or vascular surgery) | |
| 1. Give UFH (and protamine, if indicated) per usual dosing and practice | There is negligible risk of triggering acute HIT if platelet-activating antibodies are not present |
| 2. Postoperative anticoagulation, whether prophylactic or therapeutic dose, should be given with a non-heparin anticoagulant | Fondaparinux and danaparoid are viewed as nonheparin anticoagulants, although there is a low risk of clinically significant cross-reactivity with these drugs |
| 3. Perform platelet counts daily as inpatient, every 2 to 3 days as outpatient, until at least postoperative day 10 | Platelet count decrease in the first 4 postoperative days does not indicate HIT; however, any new decrease (>30%) in platelet count that begins in the postoperative day 5 to 10 window should be presumed HIT unless proven otherwise |
| Hemodialysis | |
| 1. Do the serological studies indicate that the patient can receive UFH or LMWH safely? | EIA-negative or EIA-positive/SRA-negative (or HIPA-negative) status indicates that heparin administration is safe |
| 2. Switch to UFH (or LMWH) for hemodialysis per usual practice at dialysis center | The intention (in the absence of HIT recurrence) is to continue heparin indefinitely |
| 3. Obtain pre- and postdialysis platelet counts and monitor for systemic (anaphylactoid) reactions (until approximately day 14 after the resumption of heparin) | Recurrent HIT could occur during the day 5 to 14 window after resuming heparin for hemodialysis; thus, monitoring for HIT recurrence during the day 5 to 14 time period is recommended |