The latest from Dr Bookstein and based on thrombosed rabbit IVC - but it correlates well with my personal experience so it seems reasonable to use it.

Reteplase Pulse-Spray Regimen

1. Reteplase 20 Units diluted in 1000 cc NS

2. Add 3000 Units Heparin to the 1 liter bag. This is the thrombolytic infusate.

3. Place pulse-spray catheter across thrombosed segment.

4. Pulse 0.2 to 0.5 cc of the thrombolytic infusate thru the catheter q 30 seconds.

1. Use three-way stopcock and 1 cc luer-loc syringe.
2. Each pulse consists of a rapid, forceful injection of the prescribed volume using the syringe.
3. Angiodynamics pulse-spray pump machine is preferred if available.

5. Monitor for effect, complications in the ICU.

6. No new venous and absolutely no new arterial punctures.

7. Neurochecks q 4 hours.

8. Guiac all stools and emesis.

9. CBC with platelets, PT/PTT, fibrinogen, fibrin split products - q 4hrs.

10. Stop thrombolytic and notify MD:

1. Any neurological change (ie. HA, blown pupil)
2. Frank hemorrhage of BRB not controlled with manual compression.
3. Fibrinogen level below 100 , PTT > 150 s, platelets < 50 K
4. Pain, particularly abdominal, that is out of the ordinary or unexplained by the vascular disease present.

11. Apply pressure bandage to puncture site oozing prn provided:

1. There is no neurovascular compromise to the limb
2. Oozing is not brisk
3. Enlarging hematoma is not present. Hgb stable.

12. Notify MD for any clinical changes, questions or problems and when pulses return to the affect limb.

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This regimen will also work for venous thrombolysis. May want to consider IVC filtration. A long infusion catheter is very helpful for extensive thromboses.

Call me if you have questions. - MRM

JVIR Volume 12(11); 1319-24 November, 2001

Pulse-Spray Thrombolysis with Reteplase: Optimization and Comparison with tPA in a Rabbit Model

Joseph J. Bookstein, MD1 and Fred L. Bookstein, PhD

From the Division of Research (J.J.B.), VA Hospital, La Jolla, and the Hospital of the University of California San Diego, San Diego, California; and Department of Biostatistics and Institute of Gerontology (F.L.B.), University of Michigan, Ann Arbor, Michigan.

PURPOSE: To critically evaluate and optimize methodology for pulse-spray thrombolysis with reteplase in a rabbit inferior vena cava (IVC) thrombosis model and to compare results with optimized parameters for the use of tissue plasminogen activator (tPA).

MATERIALS AND METHODS: Occlusive IVC thrombus was produced in 102 rabbits and treated 2 days later for 1 hour with pulse-spray thrombolysis using reteplase. Methodologic variables included pulse frequency, concentration and amount of reteplase, infusion versus pulse therapy, and admixture of heparin. After the rabbits were killed, residual thrombus was weighed and percent lysis was estimated on the basis of previous control values. Results were compared with those achieved with tPA in 18 additional rabbits and also with previous tPA results.

RESULTS: As in earlier tPA studies, pulse-spray methods were far more effective than constant infusion. Pulses at 30-second intervals produced better results than pulses at 2-minute intervals. At the optimal concentration of 0.02 U/mL (molarity 90 x 10-8 ), reteplase produced 79% lysis. At two-fold higher or lower concentrations, lysis was reduced by approximately 25%, and at eight-fold higher or six-fold lower concentrations, lysis was reduced by approximately 50%. Optimal concentration of tPA was 0.02 mg/mL, yielding 78% lysis. Admixture of reteplase with heparin suggested improvement, but differences were statistically insignificant.

CONCLUSION: When used with pulse-spray methodology, reteplase demonstrated a steep bell-shaped response-concentration curve similar in pitch and amplitude to that of tPA. The optimal molar concentration of reteplase was approximately three times that of tPA. However, at their respective optimal concentrations, reteplase and tPA were equally effective