Cerebrovascular Complication and Valve Surgery in Infective Endocarditis.

Infective endocarditis (IE) with neurologic complications is common in patients with active IE. The most common and feared neurological complication of left-sided IE is cerebrovascular, from septic emboli causing ischemic stroke, intracranial hemorrhage (ICH), or an infectious intracranial aneurysm with or without rupture. In patients with cerebrovascular complications, valve replacement surgery is often delayed for concern of further neurological worsening. However, in circumstances when an indication for valve surgery to treat IE is present, the benefits of early surgical treatment may outweigh the potential neurologic deterioration. Furthermore, valve surgery has been associated with lower in-hospital mortality than medical therapy with intravenous antibiotics alone. Early valve surgery can be performed within 7 days of transient ischemic attack or asymptomatic stroke when medically indicated. Timing of valve surgery for IE after symptomatic medium or large symptomatic ischemic stroke or ICH remains challenging, and current data in the literature are conflicting about the risks and benefits. A delay of 2 to 4 weeks from the time of the cerebrovascular event is often recommended, balancing the risks and benefits of surgery. The range of timing of valve surgery varies depending on the clinical scenario, and is best determined by a multidisciplinary decision between cardiothoracic surgeons, cardiologists, infectious disease experts, and vascular neurologists in an experienced referral center.

Ischemic Stroke and Intracranial Hemorrhages During Impella Cardiac Support.

Impella is a percutaneously placed, ventricular assist device for short-term cardiac support. We aimed to study acute neurologic complications during short-term cardiac support with Impella. We reviewed prospectively collected data of 79 consecutive persons implanted with Impella at a single tertiary center. Acute neurologic events (ANE) were defined as ischemic strokes or intracranial hemorrhages. Among those with ANE, specific causes of ischemic and hemorrhagic events were collected and discussed. Of 79 persons with Impella with median 8 days of support (range 1-33 days), six (7.5%) developed ANE at a median of 5 days from implant (range 1-8 days). There were three ischemic strokes, two intracerebral hemorrhages, and one subdural hematoma. Hemorrhagic events were attributed to anticoagulant use and thrombocytopenia at the time of the events. Two ischemic strokes were attributed to inadequate anticoagulation with one case of pump thrombosis diagnosed at the time of ischemic stroke. Only two of the six patients survived the acute cardiogenic shock period to achieve heart transplantation. In-hospital ischemic strokes and intracranial hemorrhages are not uncommon during short-term cardiac support period with Impella. Antithrombotic intensity, duration of device support time, and thrombocytopenia might contribute to the incidence of these events.

Cerebral Microembolization in Left Ventricular Assist Device Associated Ischemic Events.

INTRODUCTION: The significance of microembolic signals (MES) detected by transcranial Doppler ultrasound emboli monitoring (TCD-e) in patients supported with left ventricular assist devices (LVAD) remains unclear. We aimed to investigate the relationship between cerebral microembolization detected by TCD-e and acute ischemic events in LVAD patients. METHODS: We reviewed consecutive patients with acute ischemic stroke or transient ischemic attack (TIA) in a prospectively collected database of LVAD patients. TCD-e exams consisted of monitoring the middle cerebral arteries for microembolic signals (MES) over 30 minutes. RESULTS: Of 515 persons with LVAD, 41 TCD-e studies were performed in 35 patients with acute ischemic stroke or transient ischemic attack (TIA) in a median of 1 day (Interquartile range [IQR]: 0-2) after the event. MES were present in 15 (44%) TCD-e studies with a median MES count of 4 (IQR: 2-15.5). Bloodstream infections were more common in patients with MES (38% versus 8%, P = .039). There were trends for lower international normalized ratio (1.39 versus 1.69, P = .214), lower activated partial thromboplastin (33.2 versus 36.6, P = .577), higher lactate dehydrogenase (531 versus 409, P = .323) and a higher frequency of pump thrombosis (13% versus 8%, P = .637) in patients with MES compared with those without MES. CONCLUSIONS: LVAD patients with acute ischemic stroke or TIA have a high prevalence of MES on TCD-e, which may serve as a marker for a prothrombotic state. Further study of MES in LVAD patients is warranted.

Ultrasound Criteria for Assessment of Vertebral Artery Origins.

BACKGROUND AND PURPOSE: We sought to validate ultrasound as a reliable means of assessing vessel stenosis of vertebral artery origins. METHODS: We reviewed 1,135 patient charts with ultrasound of the posterior circulation performed in 2008-2015 in a single hospital. Inclusion criteria for native vessels consisted of ultrasound and digital subtraction angiography (DSA) performed within 3 months. Patients with indwelling stents were analyzed separately from native vessels. Using DSA as the gold standard, we determined sensitivity and specificity of ultrasound in detecting occlusion at vertebral artery origin. All patients with nonoccluded native vertebral artery origins were evaluated for degree of stenosis on DSA, and compared to mean flow velocity (MFV), peak systolic velocity (PSV), and end-diastolic velocity (EDV) on ultrasound. RESULTS: Among 218 vertebral artery origins in 139 patients evaluated, ultrasound showed sensitivity of 85.7% (95% confidence interval (CI): 69.7-95.2%) for occlusion and specificity of 99.5% (95%CI: 96.9-99.9%). Among 126 arteries without occlusion, <50% stenosis had average MFV (39 ± 19 cm/s), 50-69% stenosis had average MFV (68 ± 35 cm/s), and severe (70-99%) stenosis had average MFV (120 ± 93 cm/s) (P < .001). MFV cutoff value of 44 cm/s corresponded to 77% sensitivity and 70% specificity to detect vertebral artery origin stenosis >50% (C-statistic: .81). PSV value of 97 cm/s corresponded with 72% sensitivity and 70% specificity to detect >50% stenosis (C-statistic: .77). MFV cutoff value of 60 cm/s corresponded with 70% sensitivity and 82% specificity to predict 70-99% stenosis (C-statistic: .83). PSV cutoff value of 110 cm/s corresponded with 80% sensitivity and 72% specificity to predict 70-99% stenosis (C-statistic: .84). CONCLUSION: Ultrasound has good sensitivity and excellent specificity for detecting vertebral origin occlusion. Flow velocity can be used to screen for severe stenosis of vertebral artery at origin.

Clinical course of infectious intracranial aneurysm undergoing antibiotic treatment.

INTRODUCTION: Infectious intracranial aneurysm (IIA, or mycotic aneurysm) is a cerebrovascular complication of infective endocarditis. We aimed to describe the clinical course of IIAs during antibiotic treatment. METHODS: We reviewed medical records of persons with infective endocarditis who underwent cerebral angiography at a single tertiary referral center from 2011 to 2016. Aneurysms were followed with subsequent angiography for unfavorable outcome (growth, rupture, no change, or new IIA formation) or favorable outcome (regression or resolution) until endovascular therapy, aneurysm resolution, or end of observation. RESULTS: Of 618 patients included, 40 (6.5%) had 43 IIAs. Eighteen (42%) aneurysms underwent initial endovascular treatment. Twenty-five unruptured aneurysms were followed for a median 18 antibiotic days after IIA discovery (interquartile range [IQR] 4-32). Eleven (44%) aneurysms had unfavorable outcome (1 rupture, 2 new IIA formation, 6 enlargement, and 2 no change) at median 21 days (IQR 5-32). Favorable angiographic outcome was seen in 7 (28%) patients (6 resolution, 1 regression) at median 36 days (IQR 24-41). Seven aneurysms had no angiographic reevaluations but showed no evidence of rupture during clinical follow-up for median 4 days (IQR 3-12) until hospital discharge. Saccular morphology was associated with unfavorable aneurysmal outcome (p = 0.013). Longer duration of antibiotic exposure prior to IIA discovery was associated with favorable aneurysmal outcome (p = 0.046). CONCLUSION: IIAs represent a dynamic disease. Only a quarter of IIAs resolve with antibiotics alone. Saccular aneurysmal morphology might predict unfavorable aneurysmal outcome. IIA found after longer antibiotic therapy has higher likelihood of resolution or regression on antibiotic treatment.

Early versus Delayed Extracranial-Intracranial Bypass Surgery in Symptomatic Atherosclerotic Occlusion.

BACKGROUND: Clinical trials of extracranial-intracranial (EC-IC) bypass surgery studied patients in subacute and chronic stage after ischemic event. OBJECTIVE: To investigate the short-term outcomes of EC-IC bypass in progressive acute ischemic stroke or recent transient ischemic attacks. METHODS: The study was a retrospective review at a single tertiary referral center from 2008 to 2015. Inclusion criteria consisted of EC-IC bypass within 1 yr of last ischemic symptoms ipsilateral to atherosclerotic occlusion of internal carotid or middle cerebral artery. Early bypass group who underwent surgery within 7 d of last ischemic symptoms were compared to late bypass group who underwent surgery >7 d from last ischemic symptom. The primary endpoint was perioperative ischemic or hemorrhagic stroke or intracranial hemorrhage within 7 d of surgery. RESULTS: Of 126 patients who underwent EC-IC bypass during the period, 81 patients met inclusion criteria, 69 (85%) persons had carotid artery occlusion, 7 (9%) had proximal MCA occlusion, and 5 (6%) had both. Early surgery had a 31% (9/29) perioperative stroke rate compared to 11.5% (6/52) of patients undergoing late bypass (P = .04). Of patients with acute stroke within 7 d of surgery, 41% (7/17) had perioperative stroke within 7 d (P = .07). Six of nine patients (67%) with blood pressure dependent fluctuation of neurologic symptoms had perioperative stroke (P = .049). CONCLUSION: EC-IC bypass in setting of acute symptomatic stroke within 1 wk may confer higher risk of perioperative stroke. Patients undergoing expedited or urgent bypass for unstable or fluctuating stroke symptoms might be at highest risk for perioperative stroke.

MRI Presentation of Infectious Intracranial Aneurysms in Infective Endocarditis.

BACKGROUND: The radiographic appearance of infectious intracranial aneurysms (IIAs) of infective endocarditis (IE) on magnetic resonance imaging (MRI) of brain is varied. We aimed to describe the IIA-specific MRI features in a series of patients with IIAs. METHODS: Records of patients with active IE who had digital subtraction angiography (DSA) at a tertiary medical center from January 2011 to December 2016 were reviewed. MRIs performed prior to IIA treatment were reviewed for findings on susceptibility-weighted imaging (SWI), diffusion-weighted imaging, and T1 with and without contrast. RESULTS: Of the 732 patients with IE, 53 (7%) had IIAs. Of these, 28 patients had an evaluable pre-treatment MRI, in whom 33 IIAs were imaged. MRI to DSA median time was 1 day (interquartile range = 1-5). On MRI, 12 (36%) IIAs had SWI lesion with contrast enhancement, 7 (21%) had cerebral microbleeds, 3 (11%) had sulcal SWI lesion, 2 (6%) IIAs had abscesses, 3 (9%) had intraparenchymal hemorrhage, 3 (9%) had subarachnoid hemorrhage, and 6 (18%) had ischemic stroke at the anatomical locations of IIAs. Four IIAs (12%) had no correlating MRI findings, though those patients had MRI without contrast. CONCLUSION: The MRI features such as SWI lesion and contrast enhancement were the commonest MRI presentations associated with the presence of IIA.

What Causes LVAD-Associated Ischemic Stroke? Surgery, Pump Thrombosis, Antithrombotics, and Infection.

Acute ischemic stroke (AIS) is a major complication in left ventricular assist device (LVAD) population. A better understanding of clinical risk factors associated with AIS may help mitigate risk of stroke. We reviewed prospectively collected data of 477 LVAD patients from a tertiary center from October 1, 2004 to December 31, 2016. Supplemental data abstraction was performed on patients with AIS. Fifty-seven (12%) developed 61 AIS. Of 61, 17 (28%) AIS occurred perioperatively. The median time from implant to perioperative AIS was 5 days (interquartile range: 3-9). Pump thrombosis accounted for 19 (31%) of 61 AIS, and 7 (37%) presented initially with AIS before the pump thrombosis. The median lactate dehydrogenase (LDH) at the time of AIS in the pump thrombosis group (806) was higher than LDH at 1 month (437, P = 0.27) at 3 months (334, P = 0.01), and 6 months (286, P = 0.001) before AIS. Thirty-three (54%) AIS occurred while receiving inadequate antithrombotic therapy. Acute infections were common (31, 51%) in AIS and 12 (20%) were associated with acute bloodstream infection. All AIS were explained by a combination of four clinical risk factors. All LVAD-associated AIS occurred perioperatively or in conjunction with pump thrombosis, subtherapeutic anticoagulation, and bloodstream infection. The common underlying thread is occurrence of a prothrombotic state. The results of this study underscore the potential consequences of disruption of delicate hemostatic balance in patients with LVAD.

The Management of Acute Ischemic Strokes and the Prevalence of Large Vessel Occlusion in Left Ventricular Assist Device.

BACKGROUND: Ischemic and hemorrhagic strokes are frequent complications among those with left ventricular assist device (LVAD). Scarce data exist regarding the prevalence of acute large vessel occlusion (LVO) and treatment of acute ischemic stroke (AIS) in this setting. METHODS: We reviewed prospectively collected data of LVAD patient registry from a single, tertiary center from October 2004 to November 2016. Among those with AIS complications, patients were divided into early stroke (during implantation hospitalization) and late stroke (post-discharge) groups, and neuroimaging was reviewed and data on acute stroke therapy were collected. RESULTS: Of 477 persons with LVAD, 49 (10.3%) AIS occurred. The majority (29/49, 59%) of AIS occurred in-hospital. Thirty-two (65%) persons had international normalized ratios less than 1.7 at the time of AIS, but none qualified to receive acute intravenous thrombolysis. Of 25 (51%) persons who underwent CT angiography (CTA), 33% (16/49) had acute LVOs. Thirty-one percent (5/16) of persons with acute LVOs underwent intra-arterial endovascular therapy. All of 5 cases presented with middle cerebral artery syndrome with a median pre-procedural National Institutes of Health Stroke Scale of 13 (interquartile range 10-18). Successful recanalization was achieved in all 5 cases. CONCLUSIONS: In-hospital strokes and acute LVOs are common in LVAD-associated AIS. Prompt evaluation with CTA and endovascular therapy should be pursued for these critically ill patients.