Lawrence Ka Sing Wong

Angioplasty and Stenting of Atherosclerotic Middle Cerebral Arteries with Wingspan: Evaluation of Clinical Outcome, Restenosis, and Procedure Outcome

BACKGROUND AND PURPOSE: MCA is a common location of intracranial stenosis. It is relatively more peripherally located and of a smaller caliber, and could therefore be a site technically more challenging and risky for angioplasty and stenting. The study aimed to evaluate the clinical outcome, restenosis rate, and procedural safety of Wingspan stent placement for atherosclerosis in the MCA compared with stenosis in other arteries. MATERIALS AND METHODS: Patients who underwent Wingspan stent placement for symptomatic intracranial stenosis of ≥70% (or stenosis of ≥50% for recurrent ischemia despite medical therapy) were recruited prospectively and allocated into a study group (MCA stenosis, n = 35) and a control group (other stenosis, n = 25). Primary end points were the following: 1) all stroke or death rate at 1 year, and 2) significant in-stent restenosis rate at 1 year. Secondary end points were the following: 1) periprocedural complications within 24 hours, rate of TIA during the procedure, all stroke or death rate within 30 days; and 2) the inability to complete the procedure due to technical problems. RESULTS: Results of study group versus the control group were the following: degree of stenosis, 78.4 ± 10.9% versus 72.5 ± 11.2% (P value = .0456); diameter of stenosis, 0.6 ± 0.3 versus 1.0 ± 0.5 mm (P = .0017); all stroke or death rate at 1 year, 14.3% versus 12% (OR = 1.22); in-stent restenosis rate at 1 year, 10% versus 10.5% (OR = 1.05); periprocedural complication rate at 24 hours, 2.9% versus 4% (OR = 0.70); TIA rate during the procedure, 8.6% versus 4% (OR = 2.25); all stroke or death rate at 30 days, 5.7% versus 12% (OR = 0.44); and technical failure rate, 2.9% versus 0%. CONCLUSIONS: In this study, there were no significant differences in procedural safety, patient outcome, and restenosis rates of stent placement between the group with MCA stenosis and the group with stenoses located at other sites.

Symptomatic Ostial Vertebral Artery Stenosis: Treatment with Drug-eluting Stents—Clinical and Angiographic Results at 1-year Follow-up

PURPOSE To evaluate the feasibility and preliminary results of using paclitaxel-eluting stents for angioplasty and to treat symptomatic atherosclerotic ostial vertebral artery (VA) stenosis. MATERIALS AND METHODS Institutional review board approval and written informed consent were obtained for this prospective study. Nine men and one woman (average age, 65.9 years +/- 11.6 [standard deviation]) were included. Inclusion criteria were as follows: (a) Patients had angiographic evidence of VA ostial stenosis of 50% or more or stenosis of more than 45% if the contralateral VA was occluded. (b) Refractory vertebrobasilar ischemia, such as a stroke or transient ischemic attack, occurred while patients were taking one antiplatelet medication with optimal cardiovascular risk factor control. (c) Patients did not have another substantial vertebrobasilar stenotic lesion in the same territory. The primary end point was procedure safety, defined as mortality and permanent neurologic morbidity 30 days after stent placement. The secondary end point was clinical effectiveness, defined as recurrent vertebrobasilar ischemic symptoms within 12 months after stent placement and restenosis greater than or equal to 50% of the treated VA segment within 12 months after stent placement. RESULTS The degree of stenosis ranged from 46% to 83% (mean, 67.3% +/- 11.9). The technical success rate was 100%. Procedure-related complication rate, mortality rate, and permanent neurologic morbidity rate at 30-day follow-up were 0%. At 12-month follow-up, no patient reported recurrent vertebrobasilar ischemic symptoms or had VA restenosis. CONCLUSION This pilot study suggests that use of paclitaxel-eluting stents in angioplasty and to treat symptomatic atherosclerotic ostial VA stenosis are feasible and promising in terms of potential safety and effectiveness in prevention of recurrent ischemia and restenosis. These results could be helpful in the formulation of a larger prospective randomized controlled trial.

Learning curve of Wingspan stenting for intracranial atherosclerosis: single-center experience of 95 consecutive patients

Background Symptomatic brain hemorrhage was a significant cause of periprocedural stroke or death following stenting in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis trial, which called into question the safety of Wingspan stenting for intracranial atherosclerosis. This study analyzed the role of a learning curve in the safety and outcome of Wingspan stenting from the experience of 95 consecutive patients at a single center. Methods In this prospective study the endpoints were major stroke or death (modified Rankin Scale score >3) within 30 days, other neurological complications, technical procedural problems, technical success in completion of angioplasty and stenting and recurrent ischemic stroke in the corresponding vascular territory after 30 days. Data splitting into quarters was used for learning curve analysis. Results The periprocedural major stroke or death rate was 4.2% (4/95), minor stroke rate was 5.3% (5/95), total 9.5% (9/95). The technical procedural problem rate was 11.6% (11/95) and the technical success rate was 93.7% (89/95). The 89 patients were followed for 38.9±22.7 months (median 40.8, range 0.2–72, 3463 patient-months) after stenting. The risk of recurrent ischemic stroke in the corresponding vascular territory was 0.7% per patient per year (2/3463 patient-months). Guidewire- or angioplasty-related hemorrhage was the major cause of periprocedural major stroke or death (3/4, 75%) and did not occur in the last quarter. Periprocedural intracerebral hemorrhage was uncommon and perforator stroke did not occur. Conclusions There may be a learning curve for mastering the safety precautions of Wingspan stenting for intracranial atherosclerosis.

Angioplasty and stenting of intracranial atherosclerosis with the Wingspan system: 1-year clinical and radiological outcome in a single Asian center

Background This study aimed to evaluate the 1-year clinical and angiographic outcome of angioplasty and stenting of intracranial atherosclerosis using Wingspan and Gateway system. Methods In this prospective study, patients with symptomatic lesions were treated and followed clinically and angiographically by digital subtraction angiography (DSA) for 1 year. The two primary endpoints were recurrent ipsilateral ischemic stroke and in-stent restenosis (ISR) at 1 year. Secondary endpoints included periprocedural death or stroke and all strokes at 1 year. Potential factors correlated with ISR were studied using univariate and multivariate analysis. Results Treatment was attempted in 65 patients and successfully completed in 61 (93.8%). Fifty-nine patients (44 men, 15 women) aged 62.86±11.38 years with 66 stenoses (average degree of stenosis 71.78±11.23%) underwent clinical and DSA follow-up at 1 year. There were 66 stenotic lesions. ISR occurred in 11 of the 66 lesions (16.7%). Luminal gain occurred in 32 of the lesions (48.5%), an unchanged lumen in 4 (6%) and luminal loss in 30 (45.4%). The periprocedural stroke or death rate was 6.1% (4/65), including three hemorrhagic and one ischemic stroke, all of which occurred at the corresponding site and resulted in death. There were no interval strokes between the periprocedural time and the 1-year follow-up. The occurrence of ISR was correlated with the degree of stenosis before treatment and was not correlated with patient age or sex, vessel diameter, location of stenosis or failure to control risk factors for atherosclerosis. Conclusions One-year clinical and angiographic outcomes of angioplasty and stenting are promising for symptomatic intracranial atherosclerosis.

Angioplasty and stenting for intracranial atherosclerotic stenosis with nitinol stent: factors affecting technical success and patient safety.

BACKGROUND: Angioplasty and stenting using nitinol stents is a recognized treatment option for intracranial atherosclerosis. OBJECTIVE: To identify procedure-related factors that may affect patient safety and technical outcome. METHODS: In this prospective study of 57 consecutive patients, the primary end points were intraprocedural technical problems, periprocedure morbidity, and complications. Major periprocedure complication was defined as all stroke or death at 30 days. Technical failure was defined as the inability to complete the procedure because of technical or safety problems. Procedure failure was defined as a procedure outcome of technical failure or major periprocedure complication. Secondary end points were procedure-related factors that may affect patient safety and technical outcome. RESULTS: Procedure failure rate was 12.3% (7/57) (major periprocedure complication rate, 5.3% [3/57]; technical failure rate, 7% [4/57]). Initial failure in tracking of balloon or stent occurred in 20 patients, other technical problems occurred in 11 patients, including kinking or trapping of balloon catheter (2 cases), difficulty in unsheathing of stent (3 cases), forward migration of stent during deployment (4 cases), trapping of nose cone after stent deployment (1 case), fracture of delivery system (2 cases), and guidewire fracture (1 case). Unfavorable vascular morphology signified by the presence of 2 or more reverse curves along the access path was found to associate with initial failure in the tracking of instruments (OR = ∞), and occurrence of other technical problems (OR = 25). CONCLUSION: Procedure-related factors could be identified and lead to improvements in patient safety and technical outcome. Tortuous vascular morphology is a key factor to be overcome.

External Counterpulsation Reduces Beat-to-Beat Blood Pressure Variability When Augmenting Blood Pressure and Cerebral Blood Flow in Ischemic Stroke

Background and Purpose External counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown. Methods We enrolled recent ischemic stroke patients and healthy controls. Changes in the blood flow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and after ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04–0.15 Hz), and high frequency (HF; 0.15–0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated. Results We found that ECP significantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. The decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not differ from those in healthy controls. The change in flow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035). Conclusions ECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood flow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies.

Predictors of good functional outcome in counterpulsation-treated recent ischaemic stroke patients.

Objectives External counterpulsation (ECP) is a non-invasive method being investigated for ischaemic stroke. We aimed to explore predictors of good functional outcome for ECP-treated ischaemic stroke patients who completed a minimum of 10 sessions. Methods We analysed our ECP registry of ischaemic stroke patients with cerebral large artery stenosis who underwent ECP therapy at the Prince of Wales Hospital from 2004 to 2010. We included 155 patients who completed at least 10 sessions of ECP and had 3-month follow-up data as well as 52 medical controls. Functional outcomes were dichotomised into good outcome (modified Rankin Scale (mRS) 0–2) and bad outcome (mRS 3–6). We compared the differences in two groups in terms of demographics, medical history and parameters of ECP treatment. Results At 3 months after stroke, 70.5% of patients who finished the whole course of ECP had a good outcome (only 46.5% in the unfinished group and 38.5% in the medical group). Among all 207 recruited cases, 119 (57.5%) patients had a good outcome at 3 months after stroke. Compared with the bad outcome group, patients in the good outcome group were younger and had a lower baseline National Institutes of Health Stroke Scale (NIHSS) and longer ECP therapy duration. Multivariate logistic regression showed that ECP duration (OR 1.032), baseline NIHSS (OR 0.734) and age (OR 0.961) were independent predictors for a favourable outcome. Conclusions Duration of ECP therapy is first found to be an important predictor for good outcome of ECP-treated ischaemic stroke patients, in addition to the well-known prognostic factors such as age and NIHSS.

External Counterpulsation Increases Beat-to-Beat Heart Rate Variability in Patients with Ischemic Stroke

BACKGROUND AND PURPOSE External counterpulsation (ECP) is a noninvasive method used to augment cerebral perfusion in ischemic stroke. However, the response of beat-to-beat heart rate variability (HRV) in patients with ischemic stroke during ECP remains unknown. METHODS Forty-eight patients with unilateral ischemic stroke at the subacute stage and 14 healthy controls were recruited. Beat-to-beat heart rate before, during, and after ECP was monitored. The frequency components of HRV were calculated using power spectral analysis. Very low frequency (VLF; <.04 Hz), low frequency (LF; .04-.15 Hz), high frequency (HF; .15-.40 Hz), total power spectral density (TP; <.40 Hz), and LF/HF ratio were calculated. RESULTS In stroke patients, although there were no statistical differences in all of the HRV components, the HRV at VLF showed a trend of increase during ECP compared with baseline in the left-sided stroke patients (P = .083). After ECP, the HRV at LF and TP remained higher than baseline in the right-sided stroke patients (LF, 209.4 versus 117.9, P = .050; TP, 1275.6 versus 390.2, P = .017, respectively). Besides, the HRV at TP also increased after ECP compared with baseline in the left-sided stroke patients (563.0 versus 298.3, P = .029). CONCLUSIONS Irrespective of the side of the ischemia, patients showed an increased beat-to-beat HRV after ECP. Additionally, sympathetic and parasympathetic cardiac modulations were increased after ECP in patients after right-sided subacute stroke.

The potential synergism by combining external counterpulsation with intermittent theta burst stimulation in post-stroke motor function recovery.

Upper limb weakness and incoordination is a common disability following ischemic stroke. Previous studies have showed that the single application of external counterpulsation (ECP) and intermittent theta burst stimulation (iTBS) can effectively enhance the cortical motor excitability and facilitate recovery. However, it remains uncertain if sequential application of these therapies would further augment the recovery. We hypothesize a synergistic effect of ECP followed by iTBS to upper limb function may happen through improvements in both cerebral perfusion and neuron excitability.

Combined external counterpulsation and endovascular stenting treatment for symptomatic vertebrobasilar artery stenosis: two case reports

Symptomatic vertebrobasilar artery (VBA) stenosis has a poor prognosis. Intravascular stents provide a new therapeutic approach, but the long-term outcome of stenting compared with medical outcome is controversial. External counterpulsation (ECP) is a noninvasive method to improve perfusion of vital organs. We report two cases of this combination with ECP treatment in addition to receiving endovascular stenting. Two patients experienced posterior ischemic stroke. Digital subtraction angiography revealed a severe basilar or vertebral artery stenosis. Computed tomographic perfusion revealed significantly decreased perfusion of posterior artery territories. Both of them underwent combined ECP treatment and endovascular stenting of the stenosed basilar or vertebral artery, without recurrent stroke within 30 days after stenting. The two patients were independent (modified Rankin scale ≤2) at the 12-month follow-up time. Combined ECP treatment and endovascular stent placement may be effective and safe for patients with symptomatic VBA stenosis who failed aggressive medical treatment.