Recurrent Ischemic Stroke: A Manifestation of a Sinus of Valsalva Pseudoaneurysm.

An 83-year-old female presented to the emergency department with bilateral eye pain, dizziness, and acute shortness of breath. Her blood pressure (BP) at presentation was 184/93 mmHg. She was admitted for hypertensive emergency and her symptoms improved with BP control. However, during hospitalization, she developed left-sided paresthesia which on investigation was found to be secondary to ischemic stroke. She had two previous aortic mechanical valve replacements for aortic stenosis. Transthoracic echocardiogram revealed a large pseudoaneurysm of the non-coronary sinus of Valsalva that we believe was the cause of her recurrent stroke. A sinus of Valsalva pseudoaneurysm is an uncommon complication of aortic valve replacement surgery which in turn has been associated with aortic rupture, myocardial infarction, and stroke. Our case identifies a situation where sinus of Valsalva pseudoaneurysm predisposed our patient to recurrent ischemic strokes and this should be kept in mind when evaluating a patient with ischemic stroke.

A Fish Mouth Appearing Perforation of the Native Aortic Valve Due to Streptococcus infantarius subspecies coli.

Infective endocarditis due to Streptococcus infantarius with the subspecies (subsp.) coli is infrequently encountered in healthy humans. This entity is associated with hepatobiliary malignancies and colorectal neoplasia. Here, we report on a unique case of endocarditis associated with S. infantarius subsp. coli in an 80-year-old male with no known risk factors of the infective endocarditis.

Acute Stent Fracture During Balloon Post Dilation of an Everolimus Eluting Stent.

Coronary artery stent fracture is a well described complication during percutaneous intervention, with rates ranging from 0.84 to 8.4 percent in first generation drug eluting stents. Complications of stent fractures usually present with symptoms of acute coronary syndrome or progressive angina days, months to years after initial implantation. We present a case of an acute stent fracture during post balloon dilation of an everolimus eluting stent at a critical stenosis junction of a saphenous vein graft to the first diagonal of the left anterior descending artery. A shorter oversized drug eluting stent was placed to cover the stent fracture with good angiographic results. To our knowledge, this is the first incidence in literature of an acute stent fracture in a saphenous vein graft.

Reduction in Contrast Nephropathy From Coronary Angiography and Percutaneous Coronary Intervention With Ultra-Low Contrast Delivery Using an Automated Contrast Injector System.

OBJECTIVE: To evaluate the incidence of contrast-induced nephropathy (CIN) following coronary angiography and percutaneous coronary intervention (PCI) utilizing a novel ultra-low contrast delivery (ULCD) technique. BACKGROUND: Current techniques for reducing contrast volumes during angiographic and PCI procedures require the use of advanced coronary imaging methods, such as intravascular ultrasound and coronary flow wires. We propose the use of an automated contrast injector system (ACIS) with a novel programming technique that significantly reduces contrast volumes and CIN development. METHODS: From 2013 to 2014, a total of 123 patients with stage III or higher chronic kidney disease (CKD) underwent coronary angiography, PCI, or a combined procedure using the ULCD technique. A retrospective analysis was conducted to evaluate contrast volumes and rate of CIN development. Patients developing CIN were compared using tests of proportions. RESULTS: The median contrast volume was 17.9 mL (n = 123). The study cohorts comprised diagnostic (15.2 mL; n = 72), PCI (17.1 mL; n = 30), and PCI + diagnostic groups (27.9 mL; n = 21). The incidence of CIN observed in the entire cohort through day 7 was 3.3% (4/123). Seventy-five percent of the CIN cases occurred following diagnostic angiography alone. Longitudinal follow-up at 21 days identified an additional 5 cases of CIN. Compared to literature data, the ULCD technique delivers less contrast per case. CONCLUSION: The adaptation of the ULCD technique for coronary procedures significantly reduces contrast volume delivery when compared with conventional practice or previously described low-contrast techniques. The ULCD appears to be an efficacious method of limiting CIN development in a susceptible population with CKD.

A rare large right atrial myxoma with rapid growth rate.

Atrial myxomas are the most common benign intracavitary cardiac neoplasms. They most frequently occur in the left atrium. Right atrial tumors are rare, comprising 20 percent of myxomas achieving an incidence of 0.02 percent. Due to their rarity, right atrial tumor development and associated clinical symptoms has not been well described. The classical clinical triad for the presentation of left atrial myxomas--heart failure, embolic events, and constitutional symptoms--may not be applicable to right sided tumors. Also, natural development of myxoma is not well described, as surgical resection is the common practice. Previously ascribed growth rates of myxomas refer mostly to left atrial ones, as right atrial tumors are rare. We present a case of right atrial myxoma with growth rates exceeding those previously described.

Development and implantation of a minimally invasive wireless subretinal neurostimulator.

A wirelessly operated, minimally invasive retinal prosthesis was developed for preclinical chronic implantation studies in Yucatan minipig models. The implant conforms to the outer wall of the eye and drives a microfabricated polyimide stimulating electrode array with sputtered iridium oxide electrodes. This array is implanted in the subretinal space using a specially designed ab externo surgical technique that fixes the bulk of the prosthesis to the outer surface of the sclera. The implanted device is fabricated on a host polyimide flexible circuit. It consists of a 15-channel stimulator chip, secondary power and data receiving coils, and discrete power supply components. The completed device is encapsulated in poly(dimethylsiloxane) except for the reference/counter electrode and the thin electrode array. In vitro testing was performed to verify the performance of the system in biological saline using a custom RF transmitter circuit and primary coils. Stimulation patterns as well as pulse strength, duration, and frequency were programmed wirelessly using custom software and a graphical user interface. Wireless operation of the retinal implant has been verified both in vitro and in vivo in three pigs for more than seven months, the latter by measuring stimulus artifacts on the eye surface using contact lens electrodes.

Methods and perceptual thresholds for short-term electrical stimulation of human retina with microelectrode arrays.

PURPOSE: To report methods for performing epiretinal electrical stimulation with microfabricated electrode arrays and determining perceptual thresholds on awake human volunteers during acute surgical trials. METHODS: Four hypotheses were tested: (1) epiretinal stimulation can be performed during acute experiments without obviously damaging the retina or degrading vision or the health of the eye; (2) perception can be obtained 50% of the time in blind patients with charge densities below published safety limits; (3) the minimal charge needed to induce perception would be higher in patients with more severe retinal degeneration; and (4) threshold charge would be lower at shorter stimulus durations. Five subjects with severe blindness from retinitis pigmentosa and one with normal vision (who underwent enucleation of the eye because of orbital cancer) were studied. Electrical stimulation of the retina was performed on awake volunteers by placing a single 250-microm diameter handheld needle electrode or a 10-microm thick microfabricated array of iridium oxide electrodes (400-, 100-, or 50-microm diameter) on the retina. Current sources outside the eye delivered charge to the electrodes. Assessment of damage was made by observing the clinical appearance of the eyes, comparing pre- and postoperative visual acuity, obtaining retinal histology in one case, and comparing perceptual thresholds with published safety limits. RESULTS: No clinically visible damage to the eye or loss of vision occurred. Even at sites removed from stimulation, histology revealed swollen photoreceptor inner and outer segments, which were believed to be nonspecific findings. Percepts could not be reliably elicited with 50-microm diameter electrodes using safe charges in one blind patient. With the two larger electrodes, only the normal-sighted patient had thresholds at charge densities below 0.25 and 1.0 millicoulombs (mC)/cm(2) for 400- and 100-microm diameter electrodes, respectively, which is one seemingly reasonable estimate of safety derived from the product of charge per phase and charge density per phase. In blind patients, thresholds always exceeded these levels, although most were close to these limits in patient 6. The range of charge density thresholds with the 400- microm electrode in blind patients was 0.28 to 2.8 mC/cm(2). The normal-sighted patient had a threshold of 0.08 mC/cm(2) with a 400-microm electrode, roughly one quarter of the lowest threshold in the blind patients. Strength-duration curves obtained in two blind patients revealed the lowest threshold charge at the 0.25- or 1.0-ms stimulus duration. CONCLUSIONS: Threshold charge densities in severely blind patients were substantially higher than that in a normal-sighted patient. Charge densities in blind patients always exceeded one seemingly reasonable estimate of safe stimulation. The potential adversity of long-term stimulation of the retina by a prosthesis has yet to be determined.

Perceptual efficacy of electrical stimulation of human retina with a microelectrode array during short-term surgical trials.

PURPOSE: This work is part of a feasibility assessment of a retinal prosthesis as a means to restore vision to patients with blindness caused by retinitis pigmentosa. The primary goal was to assess the concordance of the form of induced perception and the pattern of electrical stimulation of the retina, and the reproducibility of the responses. METHODS: Five volunteers with severe retinitis pigmentosa and one with normal vision were studied. A companion paper in this issue provides details on demographics, visual function, surgical methods, general stimulation strategy, and data analysis. Volunteers were awake during surgery while a 10-microm-thick, microfabricated electrode array was placed on the retina. The array was connected to extraocular current sources that delivered charges to 50-, 100-, and 400-microm-diameter electrodes. Negative control trials were randomly included. Perceptual quality was judged by the similarity between the form of stimulation and perception (i.e., accuracy) and the reproducibility of responses. RESULTS: Only 1 of 40 control tests yielded a false-positive result. On average, volunteers 3, 5, and 6 reported percepts that matched the stimulation pattern 48% and 32% of the time for single- and multiple-electrode trials, respectively. Two-point discrimination in the best cases may have been achieved in two blind subjects using (center-to-center) electrode separation of 600 and 1960 microm. Reproducibility was achieved 66% of the time in the blind subjects. By comparison, in the normal-sighted subject, perceptual form was reported accurately 57% of the time, with 82% reproducibility, and two-point discrimination may have been achieved in one trial with 620-microm electrode spacing and in two trials each with 1860- and 2480-microm electrode spacing. In subjects 5 and 6, perceptual size was inconsistently related to the charge, although relatively large differences in charge (median: 0.55 microcoulombs [microC]) between two trials produced differently sized percepts. Longer stimuli did not produce rounder percepts. CONCLUSIONS: Single percepts induced by single-electrode stimulation were relatively small, but the form of percepts, especially after multielectrode stimulation, often did not match the stimulation pattern, even in a normal-sighted volunteer. Reproducible percepts were more easily generated than those that matched the stimulation pattern.