Low platelet activity predicts 30 days mortality in patients undergoing heart surgery

Do selective serotonin reuptake inhibitors increase the risk of bleeding or mortality following coronary artery bypass graft surgery? A meta-analysis of observational studies

INTRODUCTION

Depressive illness has a high prevalence in patients undergoing coronary artery bypass graft surgery (CABG). The first line treatment for depression are selective serotonin reuptake inhibitors (SSRIs) which inhibit serotonin reuptake in the presynaptic neuronal membrane and uptake by platelets, inhibiting subsequent serotonin-mediated platelet activation. This presents a theoretically increased risk of bleeding and subsequent postoperative mortality. This review aims to investigate the effects of SSRIs on postoperative bleeding, defined as the need for transfusions and re-operation for bleeding, as well as 30-day mortality in patients undergoing CABG.

METHOD

Four hundred and thirty-seven papers were screened with seven meeting the full inclusion criteria.

RESULTS

Meta-analysis demonstrated that SSRI use increased the risk of red blood cell transfusion (odds ratio (OR) = 1.15; 95% confidence interval (CI): 1.06-1.26), but resulted in no difference in the rate of re-operation for bleeding (OR = 1.07; 95% CI: 0.66-1.74). SSRI use had no effect on the rates of platelet (OR = 0.93; 95% CI: 0.79-1.09) or fresh frozen plasma (OR = 0.96; 95% CI: 0.74-1.24) transfusion nor on the mortality rate (OR =1.03; 95 CI: 0.90-1.17).

CONCLUSION

This review demonstrates that SSRIs are largely safe in cardiac surgery as no increase in mortality was observed. However, there is a significantly raised chance of red blood cell transfusion. The heterogeneous nature of the current evidence base highlights the need for further research into SSRIs and whether any effect on patient outcomes in cardiac surgery occurs.

Over-expression of cyclooxygenase-2 in increased reticulated platelets leads to aspirin resistance after elective off-pump coronary artery bypass surgery

INTRODUCTION

Aspirin resistance (AR) has been reported to present after coronary artery bypass graft causing saphenous vein graft failure. We aimed to investigate the factors that affect the anti-platelet effect of aspirin after off-pump coronary artery bypass surgery (OPCAB).

MATERIALS AND METHODS

Thirty OPCAB candidates were successively recruited. Platelet count, platelet aggregation, reticulated platelet (RP), platelets' cyclooxygenase (COX)-1 and COX-2 expressions were determined during the peri-operative period. Besides, 10 healthy volunteers were enrolled to determine the onset of the anti-platelet effect of aspirin as comparison.

RESULTS AND CONCLUSIONS

The arachidonic acid-induced platelet aggregation (PL_AA) decreased to <20% within 8h after taking 100mg aspirin in healthy volunteers. However, in the OPCAB patients, PL_AA levels remained over 20% in 16 (53.3%) patients after resuming aspirin for 24h. The surgical bleeding volumes were higher in the AR patients compared to the normal responders (512.5±192.8 vs. 314.3±94.9, p=0.002). The platelet count on Day 8, RP proportions on Days 1, 4, 8, and COX-2 level on Day 4 were significantly increased compared to their baseline levels in AR group but not in AS group. Platelet count on Day 8, RP proportion and COX-2 on Day 4 were all significantly higher in AR group than those in AS group. The surgical bleeding volume and COX-2 over-expression were predictors of post-OPCAB AR. As a conclusion, the inability of aspirin to inhibit the COX-2 created by increased RP would account for the post-OPCAB AR.