[Prevention of early graft occlusion after coronary bypass grafting by post-operative reduction of plasma fibrinogen by H.E.L.P. apheresis. First evaluation of 12 patients treated during our study (44 bypasses)].
BACKGROUND
Early graft occlusion is a known complication after CABG (Coronary Artery Bypass Grafting). The thromboembolic closure of the bypass occurs at a frequency of 5-15%, depending on the implemented vessel (arterial or venous graft). Fibrinogen as a substrate of thrombus formation plays a major role in both primary and secondary haemostasis. The operative trauma triggers the acute phase-response and also activates the clotting process. This leads to high fibrinogen levels of up to 600 mg/dl postoperatively, providing an impaired haemorrheological pattern which promotes thrombus formation. In a prospective pilot-study we examined whether drastic postoperative lowering of fibrinogen by H.E.L.P.-(Heparin-mediated Extracorporeal LDL-/Fibrinogen Precipitation) apheresis can prevent early graft vessel closure in patients undergoing CABG.


METHODS
For the purpose of this study 12 male patients (mean age 60+/-5.8 years) who underwent multivessel CABG were recruited between 12/2000 and 2/2002 according to a GCP approved protocol. The postoperative fibrinogen levels of the patients were monitored and H.E.L.P. apheresis was applied when plasma fibrinogen levels exceeded >350 mg/dl on day 1 and >250 mg/dl every following day up to day 8 after the operation. Pre- and post apheresis blood samples were obtained and reduction of plasma fibrinogen, LDL-Cholesterol and CRP were determined. Coronary angiography was performed within the 9th-16th postoperative day. To investigate the long term outcome a second coronary angiography was performed half a year after the operation.


RESULTS
A total of 44 bypass grafts (23 arterial; 21 vein grafts) were implemented in 12 patients (mean 3.6/patient) and a total of 66 H.E.L.P.-Apherses from day 1-8 were postoperatively applied (mean 5.5/patient). Fibrinogen levels were lowered from a maximum on day 2 of 447+/-112.2 mg/dl (pre-apheresis) to a minimum on day 8 of 228+/-46.2 mg/dl (pre-apheresis) demonstrating a reduction of 50%. Per single treatment the fibrinogen was lowered from 357+/-93 mg/dl (pre-apheresis) to 157+/-46 mg/dl (post apheresis); reduction: 55%. Coronary angiography revealed graft patency in 43 of 44 grafts (97.7% patency). The one occluded bypass was an Y-graft to a diagonal branch less than 1mm in diameter. No bleeding or H.E.L.P. related complications were observed.Up to now 7 of 12 patients underwent the second coronary angiography according to the study protocol. Apart from the already immediately postoperatively occluded Y-graft no new bypass-occlusion was revealed.


CONCLUSIONS
Early and extensive reduction of postoperatively elevated plasma fibrinogen levels by H.E.L.P. apheresis seems to be an efficient and safe therapeutic approach for preventing early graft occlusion in patients undergoing multivessel CABG.
Blessing
F
F
Institut für Klinische Chemie, Klinikum Grosshadern, Ludwig-Maximilians-Universität, Marchioninistrasse 15, 81377 München, Germany. Frithjof.Blessing@klch.med.unimuenchen.de
Jaeger
B R
BR
Oberhoffer
M
M
Reichart
B
B
Seidel
D
D
D000925:Anticoagulants / Q000627:therapeutic use; D001781:Blood Component Removal / Q000379:methods*; D011232:Chemical Precipitation; D008078:Cholesterol, LDL / Q000097:blood / Q000302:isolation & purification; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000209:etiology / Q000601:surgery*; D005112:Extracorporeal Circulation / Q000379:methods*; D005340:Fibrinogen / Q000302:isolation & purification*; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000209:etiology* / Q000517:prevention & control*; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D006937:Hypercholesterolemia / Q000150:complications / Q000628:therapy; D008077:Lipoproteins, LDL / Q000097:blood / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D016896:Treatment Outcome
D000925:Anticoagulants; D008078:Cholesterol, LDL; D008077:Lipoproteins, LDL; D005340:Fibrinogen; D006493:Heparin