Postoperative thrombocytopenia and subsequent consequences in acute type A aortic dissection

Abstract

Objectives

To ascertain if postoperative thrombocytopenia following open aortic surgery with a median sternotomy can predict early- and intermediate-term morbidity and mortality.

Methods

From January 2018 to December 2022, a comparison was made between patients who had and didn’t have postoperative thrombocytopenia (defined as a nadir < 75 × 103/μL after 72 h of open aortic surgery with median sternotomy). Intermediate-term mortality during follow-up was the main result, with cerebrovascular accident and acute renal injury requiring dialysis as secondary events. Inverse probability treatment weighting (IPTW) was used to account for selection bias between groups. The Kaplan-Meier method with the log-rank test was used to assess intermediate-term survivals following IPTW modification. To identify the nonlinear link between platelet nadir and mortality probability, a generalized additive mix model was applied. To help increase power in testing for the overall effect of platelet nadir on outcomes in the generalized additive mix model, the hazard ratios and 95% CIs for each subgroup and their interactions were examined.

Results

The study included 457 patients, 347 male (75.9%), with mean age of 54 ± 12 years. The last follow-up was done on April 14^th, 2023 and the median follow-up time was 16 (6-31) months. Following IPTW, patient characteristics were balanced among cohorts. Platelet nadir was found to be significantly inversely related to early-term mortality (IPTW-adjusted hazard ratio = 0.968 (0.960, 0.977), p < 0.001), and AKI requiring dialysis (IPTW-adjusted hazard ratio = 0.979 (0.971, 0.986), p < 0.001). A nonlinear relationship between platelet nadir and mortality risk probability during follow-up visually showed that the likelihood of mortality decreased with platelet nadir increased. In confounder-adjusted survival (‘postoperative thrombocytopenia not acquired’ vs ‘postoperative thrombocytopenia’; HR: 0.086 [95% CI: 0.045-0.163]; p < 0.01) analysis, non-acquired postoperative thrombocytopenia was associated with a lower risk of mortality, and the treatment benefit was validated in IPTW-adjusted analysis, which showed an HR of 0.067.

Conclusions

Early postoperative thrombocytopenia following type A aortic dissection surgery is a risk factor for morbidity and mortality. Because postoperative thrombocytopenia can indicate a poor prognosis, monitoring early postoperative platelets helps identify individuals who may develop late postoperative problems, which is performed by this affordable biomarker.

PLAIN LANGUAGE SUMMARY

What is the context?

1. The most common complications of acute type A aortic dissection included postoperative bleeding, acute kidney injury (AKI), rethoracotomy for hemostasis due to hemorrhage, stroke and even death.

2. It is unknown that platelets are associated with morbidity and mortality in type A aortic dissection.

What is new?

1. The present study suggests that early postoperative thrombocytopenia following type A aortic dissection surgery is a risk factor for short- and intermediate-term morbidity and mortality.

2. Furthermore, a nonlinear relationship between platelet nadir and mortality risk probability during follow-up visually showed that the likelihood of mortality decreased with platelet nadir increased.

3. Especially, in confounder-adjusted Kaplan-Meier survival analysis, postoperative thrombo­cytopenia was associated with a higher risk of mortality, and the effect was also validated in IPTW-adjusted analysis.

What is the impact?

This study provides further evidence that the platelet count represents a reliable early monitoring tool for the predictive value in the prognosis of acute type A aortic dissection.

Keywords:

• Postoperative thrombocytopenia
• type a acute aortic dissection
• mortality and morbidity

Acknowledgements

We thank Academic Editor Dr Petri Kovanen and reviewers for their comments and help with the manuscript. We thank and show respect to Sheng Zhao, Weidong Gu, Buqing Ni, Jiaxi Gu, Minghui Li and Hong Liu for their contributions in aortic dissection in the department of cardiovascular surgery of the first affiliated hospital with Nanjing Medical University.

Contributions

All authors participated in the method development. Zhiwei Tang developed the essence of the text, and participated in all phases of the manuscript creation. Yongfeng Shao guided the dissection procedure, discussed the results, and edited the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethics approval and consent to participate

This study was approved by the Ethics Committee of The First Affiliated Hospital of Nanjing Medical University (ID: 2021-SR-381) and conformed to the Declaration of Helsinki.

Data availability [database]

Individual data used for this study are not publicly available for proprietary reasons.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (82000305, 82070483), and Jiangsu Province Capability Improvement Project through Science, Technology and Education (ZDXK202230).