Revascularization results in the Interventional Management of Stroke II trial

Abstract

Background and purpose: Our aim was to detail revascularization results, including impact on outcome and mortality, in the Interventional Management of Stroke (IMS) II trial.

Materials and methods: IMS II was designed to obtain estimates of the efficacy and safety of reduced-dose intravenous recombinant tissue plasminogen activator (rtPA) followed by additional intra-arterial rtPA and low-energy sonography via the EKOS Primo Micro-Infusion Catheter at the occlusion in selected patients with ischemic stroke treated within 3 hours of onset. Revascularization outcomes were detailed and compared with modified Rankin Scale scores 0-2, mortality outcomes, and results from IMS I.

Results: Complete recanalization at 60 minutes occurred in 12 of 29 (41.4%) sonography microcatheter-treated occlusions. Complete recanalization was achieved at 2 hours or procedure end in 20/29 (68.9%) in the ultrasound catheter-treated group, and final thrombolysis in cerebral infarction (TICI) 2/3 reperfusion was achieved in 18/29 (62.0%) ultrasound-treated subjects. Fifteen-minute angiograms demonstrated some recanalization in 69/145 (46.7%) sonography microcatheter treatment intervals, compared with 39/111 (35.1%) in IMS I treatments in 23 subjects with reliable 15-minute angiograms (P = .046). Pooled IMS I-II data demonstrated that partial or complete recanalization occurred in 56/75 (74.6%) and good reperfusion (TICI 2/3) occurred in 46/75 (61.3%) of internal carotid artery T and M1 occlusions. Revascularization correlated with good outcome for TICI 2/3 reperfusion (P = .0004), TICI 2B/3 reperfusion (P = .0002), and arterial occlusive lesion 2/3 recanalization (P = .03).

Conclusion: IMS II provides evidence that the EKOS Primo sonography microcatheter exhibits a trend toward improved recanalization of the occlusion compared with a standard microcatheter and again confirms the correlation between recanalization and reperfusion with good clinical outcome and reduced mortality.

Fig 1.

Patient flow and treatment group designation for 81 subjects entered into IMS II.

Fig 2.

Graph depicts total cumulative complete grade 3 AOL recanalization at each 15-minute interval for the EKOS Primo sonography microcatheter (n = 29) and the standard microcatheter in IMS II (n = 14). Standard microcatheter recanalization data points at 60 and 120 minutes are also depicted. IMS I data are incomplete at 60 minutes, with 23 confirmed control arteriograms. Sixty- and 120-minute IMS I data points closely approximate the line of IMS II microcatheter recanalization. The open circle emphasizes an early equivalence of standard microcatheter to the sonography (US) microcatheter. The greatest recanalization effect (>20%) is within the first 15 minutes of microcatheter placement.

Fig 3.

Temperature (T) chart correlation to recanalization in M2 occlusion. Upper left: control arteriogram demonstrates EKOS sonography microcatheter placed in the M2 occlusion (white arrow) just before treatment time 0. Upper right: 15-minute control arteriogram demonstrates microcatheter tip retraction into the M1 segment (white arrow). Note the temperature decrease of approximately 0.2°C during the 15-minute time interval, indicating cooling of the catheter by flowing blood. Lower right: oblique 30-minute arteriogram with catheter-tip position (white arrow) proximal to recanalization of the M2 segment, with distal emboli (AOL 3 recanalization, TICI 2 perfusion). Note the temperature drop of approximately 0.4°C during the 15-minute time interval. The downward spikes of T indicate cooling by contrast injection. The spike at 25 minutes was an additional injection to confirm maintenance of catheter position, where no recanalization was yet identified. deg C indicates degrees celsius.