Project description:Platypnea-orthodeoxia syndrome, a rare condition characterized by posture-related dyspnea, is usually caused by an intracardiac shunt, hepatopulmonary syndrome, or shunting resulting from severe pulmonary disease. We report the case of a 33-year-old woman who presented with increasing dyspnea and oxygen desaturation when she sat up or arose. Our diagnosis was platypnea-orthodeoxia syndrome. A lead of a previously implanted pacemaker exacerbated a severe tricuspid regurgitant jet that was directed toward the patient's intra-atrial septum. Percutaneous closure of a small secundum atrial septal defect eliminated right-to-left shunting and substantially improved the patient's functional status. In addition to this case, we discuss this unusual condition.
Project description:Congenital thrombotic thrombocytopenic purpura (cTTP) is caused by ADAMTS13 mutations and associated with high risk of microvascular thrombosis. A 58 year old female had an ischemic stroke during hormonal fertility, and a TIA a year after. She suffered another stroke 18 years later while on warfarin. Four months after she developed severe thrombocytopenia, mild anemia, and increased LDH. Blood film showed schistocytes. She was hospitalized with presumptive TTP. ADAMTS 13 activity was undetectable without inhibitor. She developed another stroke and received plasma exchange. A homozygote ADAMTS 13 mutation was identified. Despite plasma, the ADAMTS13 activity remained < 10% and she had another stroke. Recombinant ADAMTS13 therapy was obtained through compassionate use. She receives weekly infusions maintaining ADAMTS13 trough levels above 10% without thrombotic recurrences. This case underscores the need to recognize cTTP as a cause of cryptogenic strokes, and the diagnostic value of the peripheral blood film. rADAMTS13 replacement may prevent recurrences.
Project description:Lipoprotein(a) is a plasma lipoprotein and known cardiovascular risk factor, most recently implicated in the development of high-risk carotid atherosclerotic plaques without significant carotid stenosis. We present a case of a young African-American female with recurrent embolic strokes of undetermined source. After our thorough investigation, we identified the link between a small, irregular plaque in the right internal carotid artery, and an extremely elevated plasma level of lipoprotein(a) as the source of her embolic strokes.
Project description:Up to a third of strokes are rendered cryptogenic or of undetermined etiology. This number is specifically higher in younger patients. At times, inadequate diagnostic workups, multiple causes, or an under-recognized etiology contributes to this statistic. Embolic stroke of undetermined source, a new clinical entity particularly refers to patients with embolic stroke for whom the etiology of embolism remains unidentified despite through investigations ruling out established cardiac and vascular sources. In this article, we review current classification and discuss important clinical considerations in these patients; highlighting cardiac arrhythmias and structural abnormalities, patent foramen ovale, paradoxical sources, and potentially under-recognized, vascular, inflammatory, autoimmune, and hematologic sources in relation to clinical practice.
Project description:Platypnea orthodeoxia syndrome (POS) occurs when an upright position results in acute-onset hypoxemia and is relieved with recumbency. POS can be due to intracardiac shunting, intrapulmonary shunting, ventilation-perfusion mismatch, or a combination of these. We report a case of POS that developed 3 days post liver transplantation as a result of new-onset right to left shunting across a patent foramen ovale. Right heart catheterization revealed a posteriorly directed inferior vena cava likely due to altered inferior vena cava-right atrial junction anatomy as a result of liver transplantation. The patient underwent successful transcatheter patent foramen ovale closure with a 25-mm Gore Cardioform septal occluder device with immediate and sustained improvement in hypoxia.
Project description:Low serum albumin concentrations have been associated with increased stroke risk, but the underlying mechanisms are less well studied. We aimed to investigate the association between serum albumin levels and ischemic stroke etiologies in a large, population-based, multiethnic, prospective, cohort study.Participants from the Northern Manhattan Study (NOMAS; n=2986; mean age, 69±10 years) free of stroke at baseline were followed for incident stroke (a median follow-up of 12 years). Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for baseline serum albumin levels and risk of ischemic stroke and ischemic stroke subtypes after adjusting for vascular risk factors.The mean baseline serum albumin level was 4.42±0.33 g/dL. There were 271 ischemic strokes during follow-up. Participants with serum albumin levels of 2.7 to 4.2 g/dL (the lowest tertile) had increased risk of all stroke (HR, 1.76; 95% CI, 1.32-2.35), ischemic stroke (HR, 1.67; 95% CI, 1.21-2.29), cardioembolic stroke (HR, 1.92; 95% CI, 1.10-3.34), and cryptogenic stroke (HR, 2.59; 95% CI, 1.21-5.53), compared with those with levels of 4.6 to 5.5 g/dL (the top tertile; reference). Low albumin levels (2.7-4.2 g/dL) were not associated with large vessel or lacunar stroke.Our study shows an association between low serum albumin levels and ischemic stroke, particularly cardioembolic and cryptogenic subtypes. These results suggest the potential shared pathophysiological relationship between low serum albumin levels, cardiac embolism, and cryptogenic infarction, which warrants further investigation.
Project description:Objectives:The higher than expected PFO rate in CS patients has raised concerns that paradoxical embolism maybe the pathophysiologic mechanism for strokes. However, only a small proportion of pathogenic PFOs cause CS. Therefore, accurate recognition of patients with pathogenic PFOs among all CS patients could guide clinical decision making in selecting the most appropriate treatment. The aim of this study was to devise a new algorithm to stratify cryptogenic stroke (CS) patients into pathogenic patent foramen ovale (p-PFO)- and non-p-PFO-related patients. Methods:A total of 1201 patients with acute ischemic stroke were recruited from two different medical centers, and 253 CS patients were identified. Of the 253 patients, 111 were diagnosed with PFO using contrast transcranial Doppler. Data on medical histories, neuroimaging and laboratory tests were compared in CS patients with or without PFO. Results:Compared with PFO-negative CS patients, PFO-positive CS patients showed younger onset age, lower incidence of hypertension and dyslipidemia, characteristic infarction pattern in magnetic resonance imaging and specifically altered platelet activity and coagulation function. Based on the above information, we constructed a PFO judgment formula (Hr-PFOJ) by means of feature weight estimation and predictive performance evaluation to predict pathogenic PFO in CS patients with a sensitivity of 76.3% and a specificity of 66.5%. Interpretations:Hr-PFOJ judgment formula is a useful screening tool for identification of patients with pathogenic PFO who may benefit from PFO-related treatment.
Project description:BackgroundHaving an inter-atrial shunt in the form of a patent foramen ovale or atrial septal defect increases the risk of developing cryptogenic stroke. Prompt action is required in order to prevent stroke recurrence. The source of embolization may not be clear on stroke workup.Case presentationA young female acutely presented with recurrent embolizations to the eye and brain. She was found to have an atrial septal defect. No clear intra-cardiac source of embolization was detected on workup including trans-esophageal echocardiography. Given the options between surgical versus device closure, the attending team opted for the surgical closure which yielded on direct left heart inspection small organized clots adherent to the tips of the mitral valve leaflets.ConclusionsThe case report illustrates the potential advantages of the direct surgical closure in detecting and extracting the embolization source in patients who present with recurrent cryptogenic stroke.
Project description:Despite a long and rich history of scientific investigation, fluid turbulence remains one of the most challenging problems in science and engineering. One of the key outstanding questions concerns the role of coherent structures that describe frequently observed patterns embedded in turbulence. It has been suggested, but not proved, that coherent structures correspond to unstable, recurrent solutions of the governing equation of fluid dynamics. Here, we present experimental and numerical evidence that three-dimensional turbulent flow tracks, episodically but repeatedly, the spatial and temporal structure of multiple such solutions. Our results provide compelling evidence that coherent structures, grounded in the governing equations, can be harnessed to predict how turbulent flows evolve.