Chest
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Randomized Controlled Trial
Exaggerated pulmonary hypertension and right ventricular dysfunction in high-altitude dwellers with patent foramen ovale.
There is considerable interindividual variability in pulmonary artery pressure among high-altitude (HA) dwellers, but the underlying mechanism is not known. At low altitude, a patent foramen ovale (PFO) is present in about 25% of the general population. Its prevalence is increased in clinical conditions associated with pulmonary hypertension and arterial hypoxemia, and it is thought to aggravate these problems. ⋯ These findings show, we believe for the first time, that although the prevalence of PFO is not increased in HA dwellers, its presence appears to facilitate pulmonary vasoconstriction and RV dysfunction during a mild physical effort frequently associated with daily activity.
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Comparative Study
Effect of Acute Arteriolar Vasodilation on Capacitance and Resistance in Pulmonary Arterial Hypertension.
Pulmonary vascular capacitance (PVC) is reduced in pulmonary arterial hypertension (PAH). In normal lung, PVC is largely a function of vascular compliance. In PAH, increased pulmonary vascular resistance (PVR) arises from the arterioles. PVR and PVC share pressure and volume variables. The dependency between the two qualities of the vascular bed is unclear in a state of intense vasoconstriction. ⋯ In vasoresponsive PAH, PVC is a function of the pressure response of the vasoconstricted arterioles to stroke volume. Immediately upon vasodilation, the capacitance increases markedly. The compliance vessels are, thus, the same as the resistance vessels. The immediate reduction in pulmonary arterial pressure during NO inhalation suggests that large vessel remodeling is not a major contributor to systolic pressure in these patients.
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Comparative Study
Natural History of Typical Pulmonary Carcinoid Tumors: A Comparison of Non-surgical and Surgical Treatment.
The natural history of typical pulmonary carcinoid tumors has not been described and has important implications for counseling elderly patients or patients with high operative-risk about surgical resection. ⋯ In this population-based cohort, surgical resection of lymph node-negative carcinoid tumors is associated with a survival advantage over nonoperative treatment. However, the DSS at 5 years was still high without any treatment, suggesting that observation of asymptomatic peripheral typical carcinoid tumors or endoscopic management of symptomatic central carcinoid tumors may be considered in patients at high risk for surgical resection.
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Carotid arteriosclerosis and sleep apnea are considered as independent risk factors for stroke. Whether sleep apnea mediates severity of carotid stenosis remains unclear. Sleep apnea comprises two pathophysiologic conditions: OSA and central sleep apnea (CSA). Although OSA results from upper airway occlusion, CSA reflects enhanced ventilatory drive mainly due to carotid chemoreceptor dysfunction. ⋯ Sleep apnea is highly prevalent in asymptomatic carotid stenosis. Further, it is associated with arteriosclerotic disease severity as well as presence of hypertension and diabetes. This vascular risk constellation seems to be more strongly connected with CSA than with OSA, possibly attributable to carotid chemoreceptor dysfunction. Because sleep apnea is well treatable, screening should be embedded in stroke prevention strategies.
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Diabetes mellitus is recognized as a stroke risk factor in atrial fibrillation (AF). Patients with diabetes with retinopathy have an increased risk for systemic cardiovascular complications, and severe diabetic retinopathy predisposes to ocular bleeding. We hypothesized that patients with diabetes, retinopathy, and AF have increased stroke/thromboembolism (TE) and severe bleeding risks when compared with patients with diabetes and AF who do not have retinopathy or to patients with AF and without diabetes. ⋯ Crude rates of stroke/TE increased in a stepwise fashion when patients without diabetes and with AF were compared with patients with diabetes with no retinopathy and patients with diabetes with retinopathy. However, we have shown for the first time, to our knowledge, that the presence of diabetic retinopathy did not emerge as an independent predictor for stroke/TE or severe bleeding on multivariate analysis.