Stroke as a complication of cardiac catheterization: risk factors and clinical features.

The authors aimed to delineate the risk factors and radiologic pattern of stroke complicating cardiac catheterization. Twenty-two cases were matched with three control subjects. Stroke was significantly associated with severity of coronary artery disease and length of fluoroscopy time (OR 1.96 and 1.65). The use of MRI with diffusion weighting allowed the identification of multiple asymptomatic lesions and a subset of lacunar-type infarcts (23%), which most likely occurred on an atheroembolic basis.

Balloon deflection technique: A method to facilitate entry of a balloon catheter into a deployed stent.

The entry of an angioplasty balloon into a coronary stent is occasionally difficult due to poorly expanded stent struts or calcified tissue blocking balloon passage. We describe a simple technique using a second guidewire and balloon to facilitate entry into the stent. Cathet. Cardiovasc. Intervent. 51:312-313, 2000.

The rational clinical examination. Is this patient hypovolemic?

OBJECTIVE: To review, systematically, the physical diagnosis of hypovolemia in adults. METHODS: We searched MEDLINE (January 1966-November 1997), personal files, and bibliographies of textbooks on physical diagnosis and identified 10 studies investigating postural vital signs or the capillary refill time of healthy volunteers, some of whom underwent phlebotomy of up to 1150 mL of blood, and 4 studies of patients presenting to emergency departments with suspected hypovolemia, usually due to vomiting, diarrhea, or decreased oral intake. RESULTS: When clinicians evaluate adults with suspected blood loss, the most helpful physical findings are either severe postural dizziness (preventing measurement of upright vital signs) or a postural pulse increment of 30 beats/min or more. The presence of either finding has a sensitivity for moderate blood loss of only 22% (95% confidence interval [CI], 6%-48%) but a much greater sensitivity for large blood loss of 97% (95% CI, 91%-100%); the corresponding specificity is 98% (95% CI, 97%-99%). Supine hypotension and tachycardia are frequently absent, even after up to 1150 mL of blood loss (sensitivity, 33%; 95% CI, 21%-47%, for supine hypotension). The finding of mild postural dizziness has no proven value. In patients with vomiting, diarrhea, or decreased oral intake, the presence of a dry axilla supports the diagnosis of hypovolemia (positive likelihood ratio, 2.8; 95% CI, 1.4-5.4), and moist mucous membranes and a tongue without furrows argue against it (negative likelihood ratio, 0.3; 95% CI, 0.1-0.6 for both findings). In adults, the capillary refill time and poor skin turgor have no proven diagnostic value. CONCLUSIONS: A large postural pulse change (> or =30 beats/min) or severe postural dizziness is required to clinically diagnose hypovolemia due to blood loss, although these findings are often absent after moderate amounts of blood loss. In patients with vomiting, diarrhea, or decreased oral intake, few findings have proven utility, and clinicians should measure serum electrolytes, serum blood urea nitrogen, and creatinine levels when diagnostic certainty is required.

Calcium entry attenuates adenylyl cyclase activity. A possible mechanism for calcium-induced catecholamine resistance.

In experimental animals, coadministration of calcium (Ca) salts with beta-adrenergic receptor agonists reduces the increased blood pressure and cyclic AMP (cAMP) produced by beta-adrenergic receptor agonists alone. In patients, coadministration of these drugs reduces the increased cardiac output and blood glucose produced by selective administration of beta-adrenergic agonists. The mechanism by which Ca might produce catecholamine resistance remains unclear. Healthy volunteers donated venous blood from which lymphocytes were isolated. The cAMP production was measured by radioimmunoassay under control conditions and after incubation with epinephrine or colforsin (forskolin) in the presence and absence of inhibitors. Epinephrine and colforsin produced concentration-dependent increases in cAMP production. Extracellular Ca concentration over the range from 0 to 8 mM did not inhibit basal cAMP production or that stimulated by either colforsin or epinephrine. The calcium channel agonist Bay K 8644 (50 microM) combined with normal extracellular Ca concentration significantly attenuated colforsin-induced increases in cAMP production. When barium was substituted for Ca in the extracellular fluid, the cAMP response to colforsin was restored, despite Bay K 8644. Inhibition of Ca channel permeability with cadmium or cobalt ions partially restored colforsin-stimulated cAMP production, despite the presence of extracellular Ca and Bay K 8644. These results suggest that entry of Ca ions through Ca channels attenuates adenylyl cyclase. The inhibition appears specific for Ca ions over other permeant divalent cations, and favors a possible physiologic role for the recently cloned Ca-inhibited adenylyl cyclase.

Microvascular density of the human paraventricular nucleus decreases with aging but not hypertension.

Microvascular density was determined in the supraoptic nuclei (SON) and paraventricular nuclei (PVN) of fixed brain tissue from 19 human subjects ranging in age from 30 to 85 years. Eight of these patients had hypertension. No sex- or hypertension-related differences in microvascular density were found in either the SON or PVN. However, capillary density decreased in the PVN with aging. These results indicate a differential pattern of microvascular loss in the human hypothalamus with aging.

Radiologic evaluation of esophageal motility: results in 170 patients with chest pain.

The role of radiologic evaluation of esophageal motility in patients with chest pain has been studied rarely. Consequently, we compared the results of radiologic and manometric examinations of the esophagus in 170 patients (106 women, 64 men; mean age, 53 years) with chest pain. Manometry, used as the standard, was normal in 114 (67%) patients, and showed the following abnormal diagnoses in the remaining 56 (33%): nonspecific esophageal motility disorder in 27 (48%), nutcracker esophagus in 16 (29%), diffuse esophageal spasm in 11 (20%), and achalasia in two (4%). Radiologic specificity was 93% (106/114) and overall sensitivity only 36% (20/56). Sensitivity increased to 50% by excluding those with nutcracker esophagus, a purely manometric diagnosis. Of the 20 patients in whom nonspecific esophageal motility disorder and diffuse esophageal spasm were undetected on radiologic examination, minimal manometric criteria for diagnosis were available in 18. Our results show that radiologic recognition of normal esophageal peristalsis is excellent. However, the vast majority of patients with chest pain do not appear to have abnormal esophageal motility on radiologic evaluation.