The investigators had the best success using direct aspiration and recommend it as the first-line approach.
Patients with ventricular assist device (VAD) support can feasibly be treated with endovascular therapy if they experience a large-vessel-occlusion (LVO) stroke while awaiting heart transplantation, according to a small Japanese study published online May 2, 2019, ahead of print in the Journal of NeuroInterventional Surgery.
“In Japan, a lot of patients are waiting for heart transplantation, and we see many LVO events in hospital. Of course, most of them are young people,” study author Hajime Nakamura, MD, PhD (Osaka University Graduate School of Medicine, Japan), told Neurovascular Exchange in an email. “Therefore, I think we have to try mechanical embolectomy, even in cases of VAD-support patients, as we do for normal LVO patients.”
The investigators, led by Yoshinori Kadono, MD (Osaka University Graduate School of Medicine), evaluated 12 consecutive patients (mean age 35.4 years) with VAD support who experienced 15 LVO events involving 20 arterial occlusions and who underwent an endovascular intervention between 2006 and 2017 at their institution. Median ASPECTS was 10. None of the study patients received IV thrombolysis.
Endovascular therapy was performed on 18 of the 20 occluded arteries, including balloon angioplasty in five and mechanical thrombectomy with either an aspiration system or stent retriever in 13. Successful reperfusion, defined as an mTICI ≥ 2b, was achieved in 67% of all endovascular therapies and 85% of all mechanical thrombectomies. Histological analysis revealed fibrin-rich thrombi in four of five samples. The only periprocedural complications were two symptomatic intracranial hemorrhages.
At 90 days, seven of 12 patients (58%) maintained their neurological function, defined as an mRS ≤ 2 or equal to their prestroke score. The 90-day mortality rate was 13%. Seven of the 10 cardiac transplant candidates returned to the waiting list, and three received transplants.
Unique Features, Special Challenges
All endovascular procedures were undertaken within 6 hours of stroke symptom onset. The authors speculate, however, that patients with VAD support who experience LVO stroke may have smaller ischemic cores and a larger therapeutic time window for several reasons. First, some arteries in the study were not completely occluded due to use of strong antithrombotic therapy and the nature of the thrombi, which were hard, fibrin-rich, and irregularly-shaped, and therefore less likely to deform the vessel walls. Second, ischemic tolerance may have developed in advance. “Brain tissue has chronically poor perfusion in patients with long-term heart failure; thus, collateral circulation may develop, as shown by mice developing arteriogenesis after mild cerebral hypoperfusion,” write the authors. Preceding ischemic events, including transient ischemic attacks, may have caused “ischemic preconditioning,” which also could have contributed to ischemic tolerance.
Endovascular therapy has some unique challenges in this patient population, however. “The problem [with these procedures] is that the groin puncture is difficult in pulseless patients, and the clot is very hard and difficult to catch,” Nakamura told NVX. In addition, some arteries are difficult to puncture due to injuries incurred from previous percutaneous cardiopulmonary support, he said. Four patients required ultrasound guidance for successful groin puncture. In these patients, puncture took more than 30 minutes.
In terms of removing the rigid, fibrin-rich thrombi, the investigators found balloon angioplasty and stent retriever thrombectomy to be among the most problematic approaches, with both cases of symptomatic hemorrhage occurring in patients treated with a stent retriever. They achieved the greatest success using contact aspiration. “Advantages of contact aspiration are that it does not require fragmentation of emboli and is capable of aspirating even hard and irregular shaped thrombi,” they write. They recommend that other interventionalists use this as their first-line approach.
Kadono Y, Nakamura H, Saito S, et al. J NeuroIntervent Surg. 2019;Epub ahead of print.
Nakamura and Kadono report no relevant conflicts of interest.