Silent Brain Infarcts Following Cardiac Procedures: A Systematic Review and Meta-Analysis

Abstract

Background Silent brain infarcts ( SBI ) are increasingly being recognized as an important complication of cardiac procedures as well as a potential surrogate marker for studies on brain injury. The extent of subclinical brain injury is poorly defined. Methods and Results We conducted a systematic review and meta-analysis utilizing studies of SBI s and focal neurologic deficits following cardiac procedures. Our final analysis included 42 studies with 49 separate intervention groups for a total of 2632 patients. The prevalence of SBI s following transcatheter aortic valve implantation was 0.71 (95% CI 0.64-0.77); following aortic valve replacement 0.44 (95% CI 0.31-0.57); in a mixed cardiothoracic surgery group 0.39 (95% CI 0.28-0.49); coronary artery bypass graft 0.25 (95% CI 0.15-0.35); percutaneous coronary intervention 0.14 (95% CI 0.10-0.19); and off-pump coronary artery bypass 0.14 (0.00-0.58). The risk ratio of focal neurologic deficits to SBI in aortic valve replacement was 0.22 (95% CI 0.15-0.32); in off-pump coronary artery bypass 0.21 (95% CI 0.02-2.04); with mixed cardiothoracic surgery 0.15 (95% CI 0.07-0.33); coronary artery bypass graft 0.10 (95% CI 0.05-0.18); transcatheter aortic valve implantation 0.10 (95% CI 0.07-0.14); and percutaneous coronary intervention 0.06 (95% CI 0.03-0.14). The mean number of SBI s per patient was significantly higher in the transcatheter aortic valve implantation group (4.58 ± 2.09) compared with both the aortic valve replacement group (2.16 ± 1.62, P=0.03) and the percutaneous coronary intervention group (1.88 ± 1.02, P=0.03). Conclusions SBI s are a very common complication following cardiac procedures, particularly those involving the aortic valve. The high frequency of SBI s compared with strokes highlights the importance of recording this surrogate measure in cardiac interventional studies. We suggest that further work is required to standardize reporting in order to facilitate the use of SBI s as a routine outcome measure.

Keywords: cardiac surgery; magnetic resonance imaging; silent brain infarction; transapical aortic valve implantation.

Figure 1

PRISMA flow diagram. AF indicates atrial fibrillation; DWI, density‐weighted imaging; MRI, magnetic resonance imaging; SBI, silent brain infarct.

Figure 2

Pooled prevalence of silent brain infacts (SBIs) post–cardiac procedures. AVR indicates aortic valve replacement; CABG, coronary artery bypass graft; MixedCTSx, mixed cardiothoracic surgical group; OPCAB, off‐pump coronary artery bypass; PCI, percutaneous coronary intervention; Prev, prevalence; TAVI, transcatheter aortic valve implantation.

Figure 3

Pooled prevalence of focal neurologic deficits post–cardiac procedures. AVR indicates aortic valve replacement; CABG, coronary artery bypass graft; Mixed CTSx, mixed cardiothoracic surgical group; OPCAB, off‐pump coronary artery bypass; PCI, percutaneous coronary intervention; Prev, prevalence; TAVI, transcatheter aortic valve implantation.

Figure 4

Funnel plots assessing interstudy bias for pooled prevalence of silent brain infarcts. AVR indicates aortic valve replacement; CABG, coronary artery bypass graft; mixedCTSx, mixed cardiothoracic surgical group; PCI, percutaneous coronary intervention; SBI, silent brain infarct; TAVI, transcatheter aortic valve implantation.

Figure 5

Funnel plots assessing interstudy bias for pooled prevalence of focal neurologic deficits. AVR indicates aortic valve replacement; CABG, coronary artery bypass graft; FND, focal neurologic deficits; MIXEDCTSX, mixed cardiothoracic surgical group; PCI, percutaneous coronary intervention; TAVI, transcatheter aortic valve implantation.

Figure 6

Meta‐analysis demonstrating risk ratio of focal neurologic deficits (FNDs) to silent brain infarcts (SBIs) for cardiac procedures. AVR indicates aortic valve replacement; CABG, coronary artery bypass graft; Mixed CTSx, mixed cardiothoracic surgical group; OPCAB, off‐pump coronary artery bypass; PCI, percutaneous coronary intervention; RR, risk ratio; TAVI, transcatheter aortic valve implantation.

Figure 7

Funnel plots assessing interstudy bias meta‐analysis comparing risk ratio of focal neurologic deficits (FNDs) to silent brain infarcts (SBIs). AVR indicates aortic valve replacement; CABG, coronary artery bypass graft; Mixed CTSX, mixed cardiothoracic surgical group; PCI, percutaneous coronary intervention; RR, risk ratio; TAVI, transcatheter aortic valve implantation.