Predictive factors of rehabilitation outcomes of perioperative stroke after surgery of the coronary artery and aorta: A pilot study

Abstract

BACKGROUND:

Perioperative stroke is a devastating complication of coronary artery and aortic surgery, resulting in significantly increased mortality and morbidity rates. As such, predicting rehabilitation outcomes after perioperative stroke would be valuable in establishing rehabilitation plans.

OBJECTIVE:

To identify prognostic factors of rehabilitation outcomes in perioperative stroke after surgery of the aorta and coronary arteries.

METHODS:

This study included patients who experienced perioperative stroke after coronary artery bypass grafting and aortic surgery, and underwent 3-weeks of rehabilitation. Demographic data included age, sex, diagnosis, brain lesions, and Charlson Comorbidity Index (CCI). To identify prognostic factors and the effectiveness of rehabilitation, the Modified Barthel Index (MBI), National Institutes of Health Stroke Scale (NIHSS), Medical Research Council (MRC) sum score, modified Rankin Scale (mRS) score, and Mini-Mental State Examination (MMSE) scores were investigated before and after a three-week rehabilitation period. Spearman rank correlation analyses were performed.

RESULTS:

Statistically significant improvements were observed in NIHSS, MBI, and MMSE scores after rehabilitation. Spearman rank correlation analysis revealed a significant correlation between sex, stroke type, and improvement in MRC sum score.

CONCLUSION:

The most crucial factors influencing the prognosis of perioperative stroke occurring after coronary artery or aortic surgery included sex and stroke type.

Keywords

Perioperative stroke CABG aortic surgery rehabilitation outcome sex stroke type

1 Introduction

Perioperative stroke is a devastating complication of aortic surgery and coronary artery bypass grafting (CABG). The incidence rates for perioperative stroke after surgery of the thoracic aorta and CABG are 7.3% and 1.87%, respectively (Goldstein et al., 2001; Mehta et al., 2017). Perioperative stroke following aortic surgery or CABG is associated with prolonged intensive care unit stays, delayed extubation, extended postoperative hospital stays, decreased age-adjusted survival, and significantly increased mortality and morbidity, leading to substantial financial burdens on healthcare systems (Goldstein et al., 2001).

Rehabilitation could facilitate the improvement of motor function and enhance cognitive functions and activities of daily living (ADL) in patients with perioperative stroke (Belagaje, 2017). Some previous studies have investigated the etiology of perioperative stroke after aortic surgery or CABG (Goldstein et al., 2001). However, research investigating predictive factors for rehabilitation outcomes after perioperative stroke is lacking. Understanding the factors that influence the rehabilitation outcome of perioperative stroke after aortic surgery and CABG is essential, not only to alleviate economic burdens and family caregiving responsibilities, but also to establish long-term rehabilitation and care plans.

This study aimed to identify predictive factors of rehabilitation outcomes following perioperative stroke after aortic and coronary artery surgeries.

2 Materials and methods

2.1 Study design and participants

Clinical data from consecutive patients admitted to the authors’ tertiary hospital between February 2022 and January 2024 were retrospectively analyzed. The inclusion criteria for this study were as follows: perioperative stroke after CABG and aortic surgery; transfer to the department of rehabilitation medicine of a tertiary hospital; and enrollment between February 2022 and January 2024. This study was approved by the Institutional Review Board of Ewha Womans University Mokdong Hospital (IRB No: 2024-03-039).

2.2 Data collection

Age at the time of transfer, sex, and the number of days since the onset of perioperative stroke were recorded for all patients. Comorbidity was assessed according to the Charlson Comorbidity Index (CCI). Stroke was defined as the sudden onset of acute neurological deficits along with evidence of acute brain lesions evaluated using computed tomography or magnetic resonance imaging. Brain lesions were categorized as supratentorial, infratentorial, or both, while stroke type was classified as embolic, non-embolic, or hemorrhagic. Coronary artery or aortic disease was categorized into groups based on aortic dissection, aortic aneurysm, or cases in which CABG was performed due to coronary artery occlusive disease (CAOD). In cases in which the aorta was involved, lesions were classified as ascending aorta, descending aorta, or aortic arch.

2.3 Rehabilitation therapy

All subjects underwent rehabilitation sessions 5 times per week for 3 weeks. Each daily session consisted of 2 parts: 1 h of physical therapy, 30 min of occupational therapy, and training for ADL.

2.4 Assessment of rehabilitation outcomes

Cognitive function was assessed at the time of admission using the Mini-Mental State Examination (MMSE). For functional assessment, the modified Barthel Index (MBI) was evaluated before and 3 weeks after rehabilitation. Disease severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (MRS) scores. Global muscle strength was evaluated using the Medical Research Council (MRC) score (Turan, Topaloglu, & Ozyemisci Taskiran, 2020).

2.5 Statistical analysis

Statistical analyses were performed using SPSS version 21.0 (IBM Corp., Armonk, NY, USA). Comparisons between pre- and post-rehabilitation therapy over the three-week period was performed using the Wilcoxon signed-rank test. Spearman rank correlation analysis was used to assess the relationship between improvements in demographic factors and rehabilitation outcomes.

3 Results

3.1 Clinical characteristics of the participants

Data from 7 patients, who experienced subacute hemiplegic stroke between February 2022 and February 2024, were reviewed. The demographic data are shown in Table 1.

Table 1
Demographic data of the participants

Total 7 participants Mean±Standard deviation

Age (year) 68.43±12.49

Sex (Male: Female) 4 : 3

Emergency: Elective 4 : 3

Diagnosis Aortic dissection 4

Aortic aneurysm 1

CAOD s/p CABG 2

Lesion of aorta Ascending aorta 3

Descending aorta 0

Aortic arch 2

Stroke type Embolic 3

Hemorrhagic 1

Ischemic 3

Brain lesion Supratentorial 3

Infratentorial 1

Dual 3

Charlson cormorbidity index 7.86±3.72

Period of stroke onset to rehabilitation 40.57±35.11

Total 7 participants		Mean±Standard deviation
Age (year)		68.43±12.49
Sex (Male: Female)		4 : 3
Emergency: Elective		4 : 3
Diagnosis	Aortic dissection	4
	Aortic aneurysm	1
	CAOD s/p CABG	2
Lesion of aorta	Ascending aorta	3
	Descending aorta	0
	Aortic arch	2
Stroke type	Embolic	3
	Hemorrhagic	1
	Ischemic	3
Brain lesion	Supratentorial	3
	Infratentorial	1
	Dual	3
Charlson cormorbidity index		7.86±3.72
Period of stroke onset to rehabilitation		40.57±35.11

3.2 Rehabilitation outcomes after 3 weeks’ rehabilitation

When comparing scores before and after 3 weeks of rehabilitation therapy, statistical significance was observed in the improvement of NIHSS, MBI, and MMSE scores, indicating meaningful progress (Table 2). In this study, the NIHSS demonstrated an improvement of 3.71 points, the MMSE exhibited an increase of 8.57 points, and the MBI demonstrated a gain of 14.43 points. Although the MRC sum and mRS scores exhibited trends toward improvement, they did not reach statistical significance.

Table 2
Comparison of outcomes before and after 3 weeks of rehabilitation

Pre-treatment Post-treatment Diff p-value

NIHSS 12.43±6.65 8.71±7.25 – 3.71±2.36 0.03^*

MBI 15.14±22.87 29.57±29.72 14.43±13.66 0.03^*

MMSE 8.00±10.47 16.57±9.54 8.57±6.13 0.03^*

MRCsum 35.71±11.91 38.43±11.24 2.71±6.52 0.27

MRS 4.57±1.13 4.00±1.63 – 0.57±0.97 0.16

	Pre-treatment	Post-treatment	Diff	p-value
NIHSS	12.43±6.65	8.71±7.25	– 3.71±2.36	0.03^*
MBI	15.14±22.87	29.57±29.72	14.43±13.66	0.03^*
MMSE	8.00±10.47	16.57±9.54	8.57±6.13	0.03^*
MRCsum	35.71±11.91	38.43±11.24	2.71±6.52	0.27
MRS	4.57±1.13	4.00±1.63	– 0.57±0.97	0.16

^*: p < 0.05.

3.3 Correlation analysis of demographic factors and rehabilitation outcomes

Sex and stroke type exhibited a significantly strong correlation with the difference in the MRC sum score (Supplementary Table 1). In terms of sex, among the 3 females, 2 exhibited improvement, with an mRC sum score of 0 points, while 1 experienced deterioration, with a score of – 7 points due to reinfarction. Among males, 1 had a score of 0 points, another had 4 points, and 2 showed improvement, with a score of 11 points. Overall, greater improvement in the mRC sum score was observed in males than in females.

When analyzing the mRC sum score based on stroke type, in the case of embolic ischemic stroke, 1 patient exhibited a score of 4 points, while 2 others exhibited improvement, with a score of 11 points. Hemorrhagic stroke exhibited no change in 1 patient, maintaining a score of 0 points. In non-embolic ischemic stroke, 1 patient experienced deterioration, with a score of – 7 points, while 3 others showed no change, with a score of 0 points. Based on this analysis, embolic ischemic stroke was associated with the most significant improvement in mRC sum score.

4 Discussion

This retrospective pilot study evaluated predictive factors of rehabilitation outcomes of perioperative stroke after coronary artery and aortic surgery. The results demonstrated that sex and stroke type were significantly associated with the rehabilitation outcomes of perioperative stroke in coronary artery and aortic surgeries. A greater improvement in rehabilitation outcomes was observed in males and in embolic ischemic stroke.

Of the 7 participants in this study, 4 experienced aortic dissection. According to previous studies, although aortic dissection occurs approximately twice as frequently in males, worse outcomes have been reported in females (Huckaby et al., 2022; Nienaber et al., 2004). Another study showed that females experience worse outcomes than males after undergoing CABG (Bryce Robinson et al., 2021; Nurkkala, Kauko, Palmu, Aittokallio, & Niiranen, 2022). In addition, a recent meta-analysis investigating sex differences in CABG outcomes from 2021 reported that female sex was associated with a higher risk for operative mortality (odds ratio 1.77) and late mortality (incidence rate ratio [IRR] 1.16) (Bryce Robinson et al., 2021). Previous studies have described the worse prognosis in females compared with males after CABG as being due to the greater comorbidity burden in females (Young & Cho, 2019).

According to previous studies, patients who experience ischemic stroke and those with non-traumatic intracerebral hemorrhage present sex-related differences in mortality and functional outcomes (Phan et al., 2018). A study by Rodriguez-Castro et al. (2019) reported that females exhibited a worse outcome at 3 months in both embolic and non-embolic ischemic strokes. Previous studies have indicated a slightly higher inflammatory response in females compared with males (Rodriguez-Castro et al., 2019). Additionally, other research has demonstrated that middle-age females exhibit a detrimental combination of elevated pro-inflammatory T-cells and decreased anti-inflammatory regulatory T-cells in adipose tissue, potentially fostering a pro-inflammatory environment and contributing to increased risk for cardiovascular disease (Ahnstedt et al., 2018). In summary, several previous studies have indicated that females experience worse outcomes than males after aortic dissection and CABG surgeries, and that stroke outcomes are also poorer in females. Considering these findings, it is likely that, in this study, owing to various factors, the rehabilitation outcome following perioperative stroke would have been worse in females.

Furthermore, this study revealed that stroke type influenced rehabilitation outcomes. In our study, embolic ischemic stroke demonstrated the most favorable outcome. According to a study by Dacey et al. (2005), perioperative strokes of the hypoperfusion type following CABG surgery had lower acute and long-term survival rates compared with embolic ischemic strokes. In another study, long-term disability resulting from perioperative stroke after cardiac surgery during follow-up was evidently correlated with the type of infarction (Salazar et al., 2001). Patients with a pure embolic ischemic stroke exhibited the most favorable prognosis, with an mRS score of 3.81 (Salazar et al., 2001). These results stem from the fact that perioperative stroke after cardiac surgery can be attributed to multiple etiologies. A significant potential cause of embolic stroke is associated with aortic manipulation, such as clamping and cannulation, as well as the “sandblasting effect” of flow through the aortic cannula against the aortic wall (Salazar et al., 2001). Therefore, embolic-ischemic stroke after cardiac surgery likely exhibits a more favorable outcome compared with other types of perioperative stroke because it is not primarily attributed to lower perfusion pressure of cardiopulmonary bypass or distal hypoperfusion.

The profound impact of perioperative stroke in coronary artery and aortic surgeries is demonstrated by a nearly five-fold increase in hospital mortality and a more than doubling of postoperative length of hospital stay (Roach et al., 1996). Furthermore, patients who experience perioperative stroke are only one-half as likely to be discharged to home and, therefore, incur much higher rehabilitation center costs.

5 Conclusion

Understanding the factors that may influence rehabilitation outcomes could be beneficial in determining long-term rehabilitation treatment plans and care strategies. The results of the present study suggest that considering sex and stroke type might be important when establishing such a plan.

Conflict of interest

None of the authors have any conflicts of interest to disclose.

Funding

No funding was received for this study.

Ethics statement

This study was approved by the Institutional Review Board of Ewha Womans University Mokdong Hospital (IRB No: 2024-03-039). The requirement for informed consent was waived.

Footnotes

The supplementary material is available in the electronic version of this article: .

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