Mechanical Thrombectomy for Tandem Posterior Circulation Strokes: A Systematic Review and Meta-analysis

Introduction: Tandem strokes involving vertebral stenosis or occlusion with an acute intracranial occlusion in the posterior circulation pose a complex problem for endovascular treatment. This study systemically reviews the literature on the efficacy and outcomes of mechanical thrombectomy (MT) in tandem posterior circulation strokes.

Methods: PubMed and EmBase were queried for ‘mechanical thrombectomy’ of ‘tandem stroke’ in ‘posterior circulation’. Studies meeting inclusion criteria were extracted for patient demographics, procedures, neurological outcomes, complications, and mortality. Meta-analysis was performed for variables reported by ≥3 studies on R version-4.3.2.

Results: Sixteen studies reporting 323 patients met the inclusion criteria. The mean age was 64.15 years [62.09-66.28] with 76.34%[70.83-81.08%] male representation. Hypertension was present in 69.72%[63.61-75.21%] of cases, while 38.45%[26.22-52.34%] had a smoking history. The mean presenting NIHSS score was 21.74[19.76-23.91]. Tandem occlusion involving a basilar clot occurred in 96.27%[92.83-98.10%] of cases, with 3.73%[1.90-7.17%] having a PCA clot. tPA was administered in 28.4%[23.32-34.1%] of cases, while GPIIb/IIIa antagonists was administered in 31.55%[11.84-61.27%]. MT was performed through femoral access in 92.97%[83.63-97.16%] of cases, and general anesthesia was used in 76.65%[50.60-91.32%]. Thrombectomy modality involved aspiration only in 34.04%[21.03-49.99%], stent retriever only in 32.18%[14.64-56.75%], and Solumbra in 30.57%[8.98-66.28%] of cases. First-pass TICI 2B-3 score was achieved in 45.33%[15.38-79.09%], with a final TICI 2B-3 achieved in 86.04%[78.95-91.01%] of cases after a mean of 1.87[1.36-2.57] passes and a mean onset-to-reperfusion time of 457.6[396.2-528.6] minutes. Symptomatic intracranial hemorrhage (sICH) was observed in 11.13%[7.89-15.47%] of cases, and iatrogenic vertebral artery dissection in 8.46%[4.9-14.24%]. Good outcomes (mRS 0-2 at 90 days) was observed in 37.10%[29.14-45.84%] of cases, with a mean 90-day mRS of 3.13[2.53-3.89]. A high mortality rate of 31.09%[24.73-38.26%] was observed.

Conclusion : Tandem posterior circulation strokes present a much higher mortality rate compared to non-tandem lesions. However, mechanical thrombectomy leads to excellent recanalization rates and is a suitable treatment option for tandem posterior circulation strokes.