Collateral circulation on perfusion-computed tomography-source images predicts the response to stroke intravenous thrombolysis

Background and purpose Perfusion-computed tomography-source images (PCT-SI) may allow a dynamic assessment of leptomeningeal collateral arteries (LMC) filling and emptying in middle cerebral artery (MCA) ischaemic stroke. We described a regional LMC scale on PCT-SI and hypothesized that a higher collateral score would predict a better response to intravenous (iv) thrombolysis. Methods We studied consecutive ischaemic stroke patients with an acute MCA occlusion documented by transcranial Doppler/transcranial color-coded duplex, treated with iv thrombolysis who underwent PCT prior to treatment. Readers evaluated PCT-SI in a blinded fashion to assess LMC within the hypoperfused MCA territory. LMC scored as follows: 0, absence of vessels; 1, collateral supply filling 50%; 2, between>50% and <100%; 3, equal or more prominent when compared with the unaffected hemisphere. The scale was divided into good (scores 23) vs. poor (scores 01) collaterals. The predetermined primary end-point was a good 3-month functional outcome, while early neurological recovery, transcranial duplex-assessed 24-h MCA recanalization, 24-h hypodensity volume and hemorrhagic transformation were considered secondary end-points. Results Fifty-four patients were included (55.5% women, median NIHSS 10), and 4-13-23-14 patients had LMC score (LMCs) of 0-1-2-3, respectively. The probability of a good long-term outcome augmented gradually with increasing LMCs: (0) 0%; (1) 15.4%; (2) 65.2%; (3) 64.3%, P=0.004. Good-LMCs was independently associated with a good outcome [OR 21.02 (95% CI 2.23197.75), P=0.008]. Patients with good LMCs had better early neurological recovery (P=0.001), smaller hypodensity volumes (P<0.001) and a clear trend towards a higher recanalization rate. Conclusions A higher degree of LMC assessed by PCT-SI predicts good response to iv thrombolysis in MCA ischaemic stroke patients.