Patent foramen ovale: anatomy versus pathophysiology--which determines stroke risk?

This study investigated anatomic and pathophysiologic variables that may determine which patent foramen ovale (PFO) are associated with cerebrovascular accidents (CVAs). Anatomic features of a PFO have been identified as risk factors that predispose certain people to cryptogenic strokes (strokes of unknown cause). However, potential pathophysiologic variables that can determine the pressure gradient between left and right atria, which could influence the right-to-left shunt through a PFO, have not been examined. A retrospective study included 78 consecutive patients in whom PFOs were detected during routine transesophageal echocardiography examination. Group I included 36 patients with CVAs of unknown cause (cryptogenic stroke). Group II included 42 patients without CVAs whose PFOs were incidental findings. Anatomic features measured included separation and overlap between septum primum and septum secundum, interatrial septal motion, and the relative size of the right-to-left shunt with peripheral saline solution contrast injections. Pathophysiologic variables considered were those that could cause elevated left atrial pressure, thereby minimizing the right-to-left shunt.Patients with a clinical neurologic event (group I) had a larger right-to-left shunt volume of contrast bubbles than did patients with asymptomatic PFO (group II; P =.004). The size of the overlap between septum primum and septum secundum was less in patients from group I as compared with patients from group II (7.5 +/- 3.4 mm versus 9.9 +/- 6.0 mm; P =.026). However, other anatomic features of PFO that are determinants of the "opening" were not significantly different between the 2 groups. No statistically significant difference was found in the distance of the separation between septum primum and septum secundum (2.5 +/- 2.0 mm versus 1.9 +/- 1.6 mm; P = not significant). The prevalence of interatrial septal aneurysm was also similar between the 2 groups (28% versus 21%; P = not significant). However, the prevalence of variables that could potentially raise left atrial pressure was greater in patients without CVA as compared with those with a CVA (48% versus 14%; P =.01). In our study, anatomic features alone did not determine interatrial shunt size and pathophysiologic variables that could raise left atrial pressures did differentiate between patients with a PFO with a CVA/transient ischemic attack and those without it. Thus, both anatomic and pathophysiologic mechanisms should be considered in determination of the potential clinical significance of a PFO.     

Patent foramen ovale in patients with tension headache: is it as common as in migraineurs? An age- and sex-matched comparative study

The association of patent foramen ovale (PFO) and atrial septal aneurysm (ASA) with migraine headache attack (MHA) has been clearly shown. The same findings have been recently demonstrated also in cluster headache. Although tension-type headaches (TTH) are the most common kind of headache, their association with these atrial septal abnormalities has never been studied before. The study was conducted to clarify whether there was a significant association between the presence of such atrial septal abnormalities and tension headache, when compared with migraineurs. One hundred consecutive patients with migraine and 100 age- and sex-matched subjects with TTH and 50 healthy volunteers with no headache were enrolled in the study and underwent a complete transesophageal echocardiographic study with contrast injections at rest and with the Valsalva maneuver. There was no significant difference between the age and the sex of the participants of the three groups. The overall prevalence of PFO was 23% in patients with TTH and that of large PFOs was only 11%. The 23% prevalence of PFO in patients with TTH was not statistically different from 16% found in our normal control group. Furthermore, we found a significantly higher prevalence of PFO in migraineurs (50%) when compared with patients with tension headache (p < 0.001). This was also true for the collective presence of large PFOs and ASAs (35%) (p < 0.001). Although atrial septal anomalies have an association with MHA, they do not have a significant association with TTH.     

Does smoking affect hospital use before death? A comparison of ever- and never-smokers in the last years of life

BACKGROUND: Given the apparent greater use of health care services by smokers and predictions of higher costs for a never-smoking population, we aimed in this study to determine whether the acute hospital costs in the last years of life of never- and ever-smokers differed before death using a database of the decedents in 1 year in Hong Kong. OBJECTIVES: To compare the acute hospital use of ever- and never-smoker decedents. METHODS: The data on cause of death, personal characteristics, and public hospital discharges were linked for all decedents in 1998 in Hong Kong. The incidence rate ratio was used to compare, for ever- and never-smokers, the number of days spent in an acute hospital over the prior 7 years. Analyses were done using specific and all cause mortality, adjusted for sex, lifestyle factors, and life expectancy. RESULTS: Compared with never-smokers who died of the same condition, ever-smokers who died of chronic obstructive pulmonary disease used 28% more acute hospital bed days and those dying of smoking-related cancer 9% fewer. These differences cancelled out over the case-mix of deaths with no net difference in acute bed day use by smoking status for all-cause mortality. CONCLUSIONS: There was no difference in acute hospital bed days in the last years of life of ever- and never-smokers but some differences by cause of death. Reducing smoking in this population will not increase acute hospital use.     

Artificial rehydration in the last days of life: is it beneficial?

Dehydration is a common concern in palliative care, and can be an emotive issue for patients and their families (Patchett, 1998). Family members instinctively wish to continue caring for a dying relative, and no more so than by giving nourishment. When the time comes that food cannot be tolerated, giving fluid can seem to be the last way of providing the patient with comfort and nurture. Dehydration may be perceived as the reason for death, rather than a natural part of the dying process. Is it therefore reasonable to give patients fluid by an alternative method? Hypodermoclysis (HDC), or subcutaneous hydration, is sometimes used to administer fluids in the last days of life in a palliative care setting. This article aims to consider the benefits and problems associated with artificial rehydration in these circumstances.     

Clinical evaluation of a novel occluder device (Occlutech<Superscript>®</Superscript>) for percutaneous transcatheter closure of patent foramen ovale (PFO)

Background

We investigated the safety, feasibility and usefulness for closure of PFO with the new nitinol meshwire PFO-occluder device (Occlutech Figulla^®-single layer occluder) with an unique braiding technology which allows a 50% reduction of meshwork material on the left atrial side in combination with a greater flexibility as compared to the Amplatzer^® occluder device.

Methods

The retention discs of the new PFO Occlutech Figulla^® single layer device (23/25 mm) are connected by a 3 mm waist in the centre with only one right atrial side hub. The left atrial disc is a single flat layer covered by an ultrathin polyethylene terephthalate (PET) patch. We investigated the safety, feasibility and usefulness for closure of PFO in a multicenter clinical trial. Indications for closure included cryptogenic stroke with evidence of a patent foramen ovale in transesophageal echocardiography (PFO max. diameter 13 mm according to sizing balloon). The device was implanted in 36 patients (mean age 57, 18–80 years) by means of fluoroscopy and transesophageal echocardiography (TEE) using a 9 French delivery sheath and employing a femoral vein approach. Both acetylsalicylacid 100 mg/d (6 months) and clopidogrel 75 mg/d (3 months) were administered post interventional. A transthoracal (TTE) and transesophageal echocardiography follow-up examination was performed after 1, 2 and 6 months (TTE day 30 and 180; TEE day 60).

Results

The device was successfully implanted in 36 pts. In one patient PFO implantations was attempted but not crossed with a guide wire. Perioperativly there were no major in-hospital-adverse events or complications thromboembolism, occluder dislodgement, infection or myocardial infarction. One patient had transient atrial fibrillation 2 h after implantation, which terminated medically after 12 h. TEE studies in the remaining 35 pts (one pt was unwilling to further participate) showed a residual shunt in 8.6% (3/35) after 60 days and a left-to-right shunt in 2.6% (1/35) of pts. After 180 days one pt with severe arteriosclerotic heart disease and A.carotic stenosis revealed a stroke without evidence of cardioembolic origin or devices thrombosis.

Conclusions

The novel Occlutech Figulla^® PFO N single layer device appears to be safe, feasible and useful for PFO closure despite a 50% reduction of the meshwire, no distal hub and an improved flexibility of the left atrial disc.

     

Thrombus in transit within a patent foramen ovale: An argument for consideration of prophylactic closure?

Recurrent pulmonary embolism (PE) in prothrombotic patients with patent foramen ovale (PFO) is not considered a setting for elective PFO closure. We describe a 35-year-old woman with known PFO, recurrent PE on warfarin, and Klippel-Trenaunay syndrome-a condition with predisposition for thromboembolism-who suffered concurrent saddle PE and devastating stroke with further impending paradoxical embolus across the PFO. Optimal management in patients with biatrial thromboembolus caught in transit across PFO is challenging. Patients with recurrent PE, prothrombotic states, and PFO should be considered for PFO closure. Prompt diagnosis of impending paradoxical embolus with echocardiography and consideration of surgical removal and PFO closure are critical.     

House calls: is there an APN in the house?

PURPOSE: To report how a group of geriatric advanced practice nurses (APNs) participated in a house calls program that increased access to care for homebound and frail community-dwelling elders. DATA SOURCES: Selected literature and author experiences, illustrated with clinical examples. CONCLUSIONS: Many frail older adults are unable to access healthcare due to functional impairments related to multiple, chronic medical conditions. Many of these adults inappropriately utilize the emergency department for episodic care. IMPLICATIONS FOR PRACTICE: The model of care maximizes utilization of APNs to provide cost effective, culturally sensitive, quality care. The goal of geriatric assessment and primary care in this practice is to add quality to later years of life, promoting dignity and comfort to older adults and their families.     

How accurate is glucose analysis in the presence of multiple interfering substances in the neonate? (glucose analysis and interfering substances)

Whole blood glucose testing by reagent sticks is inaccurate at low plasma glucose concentrations and with varying hemalocrit. Both conditions are frequently seen in newborn infants. Therefore plasma glucose analysis is the preferred method for newborn glucose monitoring. We encountered unanticipated difficulties in plasma glucose measurement by the automated hexokinase method caused by the combinations of plasma free hemoglobin, bilirubin, and plasma triglycerides, which are frequently elevated in newborn plasma. We determined the adverse effects of various combinations of these interfering substances on glucose analysis by the hexokinase method and demonstrated that accurate analysis is possible by a 1:1 plasma dilution only at high plasma glucose levels but not at the more critical low plasma glucose concentration. The dilution reduced the number of repeat specimen required in newborns. But 1:1 plasma dilution overestimated the glucose levels at low plasma glucose values, and therefore this automated hexokinase method is not suitable for glucose analysis in the newborn. Glucose-oxidase remains the method of choice for plasma glucose analysis in neonates. This information is important because using this hexokinase methodology, one might miss hypoglycemia in the newborn. © 1996 Wiley-Liss, Inc.     

Nursing home staffing: is there a nurse in the house?

With an ever-increasing emphasis on cost containment, the health care industry has been expanding its use of unlicensed personnel. The danger of substituting unlicensed assistive personnel for registered nurses threatens the public's ability to secure the full range of nursing care services.     

The P2X7 ATP receptor in the kidney: a matter of life or death?

P2X7 is an intriguing membrane receptor for the extracellular nucleotide ATP, which functions as a ligand-gated ion channel; it can activate cell membrane permeabilization and also has a wide range of downstream signaling pathways, including mediation of inflammatory responses and modulation of cell turnover. Despite recent identification of P2X7 receptor protein in the renal tract, the biological and potential pathological functions of this receptor and its signaling cascades in the kidney are not yet fully understood. P2X7 receptor protein is expressed in normal kidney development, predominantly in the condensing mesenchyme, and later in the maturing and adult derivatives of the ureteric bud. Glomerular expression of the molecule is scarce in normal kidney, but is upregulated in chronic and inflammatory conditions, suggesting a role in the inflammatory response or in repair and remodeling in these settings. P2X7 receptor expression in the adult collecting ducts of murine kidney, as well as the collecting duct cysts in autosomal recessive polycystic kidney disease, has been described and agonists of the receptor can modulate the development of renal cysts in an in vitro model of cyst formation derived from the cpk/cpk mouse. Further investigation of the function of the P2X7 receptor in normal and abnormal kidneys might lead to novel therapeutic targets in a wide range of renal diseases.