Liver Fibrosis Assessed by Fib-4 Score Unmasks Beneficial Effects of Off-Pump over On-Pump CABG

Background: Heated debates have arisen over potential advantages of avoiding cardiopulmonary bypass during coronary artery bypass grafting (Off-Pump CABG). Guidelines recommend Off-Pump in cases with elevated risks. Yet, in randomized patient populations, no survival advantage of Off-Pump has ever been documented. However, randomized patient populations mainly consist of selected low-risk individuals. One prohibitive risk factor for trials is liver cirrhosis, but earlier affections of liver function, such as liver fibrosis, have never been directly evaluated in CABG. We utilized the Fib-4 score to compare On-Pump and Off-Pump CABG in our elective or urgent CABG patients.

Methods: Between 1999 and 2023, 5,327 patients underwent elective or urgent CABG surgery. Of these, 1,466 (27.5%) were performed On-Pump, while 3,861 (72.5%) were conducted Off-Pump. We employed the Fib-4 score (calculated from ALT, AST, platelet count, and patient age) to assess potential liver fibrosis. A score below 1.3 indicates the histological absence of fibrosis, while a value above 3.25 suggests advanced liver fibrosis or cirrhosis. We present the mortality rates of Off-Pump and On-Pump CABG in relation to the Fib-4 score and comparable statistical analyses.

Results: Operative mortality increased with rising Fib-4 values, both in the On-Pump and Off-Pump patients. Demographics of Off-pump did not differ from On-Pump patients. There was no significant difference in operative mortality between Off- and On-Pump surgeries when the Fib-4 score was below 1.2 (1.9% vs. 2.3%, p = 0.61). However, in patients with a Fib-4 score above 1.2, mortality rates were 3.2% in Off-pump and 6.0% in On-Pump (p < 0.001). In the group of patients with a Fib-4 score >1.2 who underwent On-Pump surgery, there were significantly higher rates of low cardiac output (LCO), tamponade, rethoracotomy, resuscitation, stroke, and postoperative atrial fibrillation compared to off-pump. This difference in mortality increased with rising Fib-4 scores. In patients with Fib-4 scores exceeding 3.25, operative mortality was 6.7% for Off-Pump compared to 15.7% for On-Pump patients (p = 0.002).

Conclusion: Off-Pump appears to be superior to On-Pump CABG in patients with signs of early liver fibrosis. In addition, the Fib-4 score is a specifically valuable tool for assessing cardio-surgical risk, because it allows identification of elevated risks at times when individual laboratory values are still normal.

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Artikel online veröffentlicht:
13. Februar 2024