Case 2: Emergency Mechanical Thrombectomy for Acute Cerebral Thromboembolism

DANG NGUYEN1, CUONG TRAN CHI2, TUAN TRAN QUOC2, CHINH NGUYEN DUC2, LUAN TRAN MINH2

1: Can Tho University of Medicine and Pharmacy VIETNAM.

2: Medical University of Ho Chi Minh City VIETNAM

 

ABSTRACT

Treatment for ischemic stroke has remained uncertain. So far, the intravenous thrombolysis was accepted commonly, and in the mean time, mechanical thrombectomy/ intra-arterial thrombolysis has been increasingly applied as cerebral thromboembolism therapy.

                                                     

We are reporting a case of a 65-year-old, Vietnamese gentlemen who was taken into HCM CT University Medical Center with symptoms of acute left hemiparesis. CT scan showed dense MCA sign on the right side without changes in parenchyma density nor intracranial hemorrhage. His estimated admission time was about 5 hour after the onset and was over indicated for intravenous thrombolysis. He was experienced mechanical thrombectomy and the right occluded MCA was successfully recanalized. His movement on the left side was improved slightly right after the procedure, however on CT scan images, only part of the right MCA territory was salvageable due to prolong waiting time. Via this case, we highlight the role of catheter based rtpa/thrombectomy in acute ischemic stroke and the importance of time period before the procedure being crucial for brain salvageability.

 

INTRODUCTION

Besides supporting treatment, the current curable methods for ischemic stroke management includes intravenous thrombolysis, intra-arterial thrombolysis, mechanical thrombectomy, angioplasty or stenting. However, currently they are all in controversy. So far, the intravenous thrombolysis remained popularly approved, but the successful rate still seems limited with regular risk of complication. Concurrently, the mechanical thrombectomy has been proven to have a role in management of acute stroke. Moreover, the range of clinical recovery is dependent on the time duration from symptom onset until the procedure.

 

CASE REPORT

Mr P is a 65 year-old, Vietnamese, gentlemen who was brought to Ho Chi Minh CT university medical center with sudden onset of left hemiparesis. On arrival clinical assessment, his Glasgow comma scale (GCS) was 11 (movement 5, voice 3, eye3). His muscle strength of the left leg was 2/5, and that of the left hand was 0/5. Auscultation revealed an atrial fibrilation with rapid ventricle response which was confirmed by electrocardiography. Plain CT scan showed no evidence of intracranial hemorrhage. There was suspicious of dense right middle cerebral artery (MCA) sign and the brain parenchyma was normal in density.

 

A swift discussion between the neurology, emergency and neurointervention teams for an optimal management had taken place. The diagnosis was likely to be infarction due to acute thromboembolus secondary to atrial fibrilation. The National Institute of Health stroke scale (NIHSS) assessment gave a score of 7 which indicated a moderate stroke. Based on the history, the time from the symptom onset until the admission was about 5 hours. A final decision of catheter based thrombectomy/rt-PA was indicated because the IV thrombolysis was over-indicated. A quick consent between the patient relatives and the neurointerventionist was done when the patient was being transferring into the angiosuite.

 

There was a little of delayment during preparation before starting the procedure. The total preparation time was about 2 hour including CT scan, GA and discussion. The total time from the onset was 7 hours. The cerebral angiogram was performed under general anesthesia. The diagnostic cerebral angiography images show total cut-off of the M1 portion of the right MCA which was likely due to acute thrombus emboli (Figure 1). The other cerebral vessels were normal and at that time we swiftly decided to proceed with mechanical thrombectomy.

 

Due to the tortuosity of the right ICA, with difficulty, a Corail 8F balloon-carrying guiding catheter was inserted with its tip at the distal cervical portion of the right internal carotid artery (ICA). The 2.4F Rebar microcatheter and hybrid microwire .017” was used for canulation of the right middle cerebral artery. The microwire and microcatheter were managed to be threaded through the clot eventually. The microguidewire was withdrawed and the Solitaire clot-retriever stent was inserted. The stent was deployed and retrieved 4 times with a bit of clots obtained at the first threes. Finally one major piece of clot was obtained at the last retrieval. Check run showed total recanalization of the right MCA and good revascularization of the right MCA territories (Figure 2). The total time of procedure was 1.5 hours.

 

Post procedure, he was transferred to the intensive care unit after the thrombectomy for hemodynamic supports. He gained a full GCS subsequently and his vital signs was normal. His movement on the left side was recovered back but the strength was only equal to the pre-procedure levels. On the next day, his movement improved which were 3/5 on the left leg and 1/5 on the left hand. Repeated CT scan showed hypodensity at the right MCA territories suggestive of infarction. Three day later he was transferred to the neurology department and his movement of the left side had improved slightly to 4/5 in the left leg and 2/5 in the left hand.

 

DISCUSSION

 

Intravenous (IV) thrombolytic therapy is currently generally accepted and it effectiveness has been relatively favourable. In the trial of the 624 ischemic stroke patients administered doses of 0.9mg/kg IV recombinant tissue plasminogen activator (rtpa) within 3 hours of onset, approximately 31-50% of stroked patients could achieve complete or nearly complete neurological recovery after 3 months. The risk of hemorrhage was 6.4%. Death rate was 17% at 3 months and 24% after 1 year (1). A series of 4 trials by European Cooperative and Acute Stroke Study (ECASS I and II) and Alteplase thrombolysis for Acute Noninterventional Therapy in Ischemic Stroke (ATLANTIS A and B)  showed similar effect with the treatment initiated within 3 hours of  the onset (2, 3).

 

One of the important aspects in using rtpa is the point of time for drug administration. It is suggested that the early the initiation of treatment, the better the result.  In a study of rtpa administered up to 6-hour duration from the onset, the result showed increasing rate of excellent outcome within 3-4.5hours. However, it created no significant increase in that of excellent outcome at the point of 4.5 to 6 hour time and conversely, increased the rate of parenchymal hemorrhage (6.9% in rtpa group vs 1% in placebo) and mortality (15% in rtpa group vs 10% in placebo) (4).

 

Beside the risk of intracranial hemorrhage, the rtpa has also embedded some other rare adverse effects including systemic bleeding, myocardial rupture if rtpa administered in a few days within the myocardial infarct, anaphylaxis, angioedema (1.3-5.1%) (5). 

 

Endovascular intervention recently has offered substantial number of options for treatment of stroke including intra-arterial fibrinolysis, mechanical clot retrieval, acute angioplasty and stenting. The intra-arterial approach is considered more efficacious for recanalization of the proximal arterial occlusion than intravenous thrombolysis. A favourable outcome from a trial comparing between intravenous thrombolysis and intra-arterial urokinase showed 53% of recanalization in intra-arterial urokinase group compared to 23% in intravenous urokinase group (6).

 

The results of Prolyse in Acute Cerebral Thromboembolism (PROACT) II trial with the treatment starting time within 6 hours of onset showed 66% of recanalization achieved by intra-arterial fibrinolysis. The major risk of intra-arterial thrombolysis was bleeding which were 10% in the intra-arterial thrombolysis group and 2% in the controlled group infused with placebo. However, the mortality rates ware similar in the two groups (7). Results of the Middle cerebral artery Embolism Local fibrinolytic intervention Trial (MELT) also showed similar effectiveness and consistent hemorrhagic rate to the PROACT II trial (8).  

 

Mechanical thrombectomy can be considered as a primary reperfusion strategy or can be in conjunction with thrombolysis to achieve recanalization in patient with acute ischemic stroke. The technique could be performed via fragmentation, blood clot retrieval and/or fibrinolytic penetration. Many clot retriever devices are currently available including Merci retriever system, Penumbra system, Solitaire FR, Trevo Retriever. 

 

The effectiveness of these devices was various in different studies. In a report of treatment for 157 ischemic stroke patients experienced mechanical thrombectomy using Penumbra system, the patient was presented with NIHSS score >8 and the treatment was initiated within 8 hours of symptom onset. Those presented within 3 hours either was refractory or impractical for IV thrombolysis. The partial and complete revascularization rate was achieved at 87% which was very encouraging. The procedural complication happened in 9 cases and device malfunction was in 3 cases. After following up 90 days, all-cause mortality was 20% but 41 % of patients achieved modified Ranking Scale of 0-2 (9).

 

In this patient, since the time of onset was 5 hours, he did not have intravenous thrombolysis due to overindication. Technically, his occluded right MCA was successfully saved after the thrombectomy, but unfortunately, his brain still have areas of infraction which was attributed to the prolong preparation and delayed procedure initiation. Clinically he had partial recover from disability, but his infarct areas after the procedure was believed to be smaller than it should be.

 

CONCLUSION

Mechanical thrombectomy has been proven to be a potential option for acute stroke management. Early procedure initiation would help to increase the likelihood of cerebral salvageability.

 

 

 

REFERENCES

1. The national Institute of Neurological Disorders and Stroke rTPA Stroke Study group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med. 1995;333:1581-1587.

2. Kaste M, Hacke W, Fieschi C. Result of European cooperative acute stroke study (ECASS). Cerebrovasc Dis. 1995;5:225.

3. Hacke W, Kaste M, Fieschi C, Von Kummer R, Davalos A, Meier D et al. Randomised double-blind placebo-controlled trial of thrombolytic therapy with intravenous alteplase in acute ischemic stroke (ECASS II). Second European-Australasian Acute stroke study investigators. Lancet. 1998;352:1245-1251.

4. Hawke W, Donnan G, Fieschi C, Kaste M, Von Kummer R, Broderick JB et al. Association of outcome with early stroke treatment: pooled analysis of ATLATIS, ECASS and NINDS rt-PA stroke trials. Lancet. 2004;363:768-774.

5. Lyden PD. Thrombolytic therapy for acute stroke. 2nd ed. Totowa, NJ: Humana Press. 2005.

6. Mattle HP, Arnold M, Georgiadis D, Baumann C, Nedeltchev K, Benninger D et al. Comparison of intra-arterial and intravenous thrombolysis for ischemic stroke with hyperdense middle cerebral artery sign. Stroke. 2008;39:379-383.

7. Furlan A, Higashida R, Wechsler L, Gent M, Rowley H, Kase C. Intra-arterial prourokinase for acute ischemic stroke: the PROACT II study: a randomized controlled trial: Prolyse in acute cerebral thromboembolism. JAMA. 1999;282:2003-2011.   

8. Ogawa A, Mori E, Minematsu K, Taki W, Takahashi A, Nemoto S et al. Randomized trial of intra-arterial infusion of urokinase within 6hours of middle cerebral artery stroke: the middle cerebral artery local fibrinolytis intervention trial (MELT) Japan. Stroke. 2007;26:807-812.

9. Tarr R, Hsu D, Kulcsar Z, Bonvin C, Rufenacht D, Alfke K et al. The POST trial: initial post-market experience of the Penumbra system: revascularization of large vessel occlusion in acute ischemic stroke in United State and Europe. J Neurointerv Surg. 2010;2:341-344.  

 

Figures:

Figure 1: Pre-thrombectomy image shows a cut-off appearance at M1 portion of the right MCA (arrow).

 

 

 

 

 

 

 

 

 

 

 

Figure 2: Post-thrombectomy image with complete recanalization of the right MCA (arrow head).

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