Impact and Predictors of Noncircular Left Ventricular Outflow Tract Shapes on Estimating Aortic Stenosis Severity by Means of Continuity Equations

Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm²) was underestimated by the standard method (1.05 ± 0.47 cm²; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.     

Stones, bones, and heredity

Genetic disorders of mineral metabolism cause urolithiasis, renal disease, and osteodystrophy. Most are rare, such that the full spectrum of clinical expression is difficult to appreciate. Diagnosis is further complicated by overlap of clinical features. Dent's disease and primary hyperoxaluria, inherited causes of calcium urolithiasis, are both associated with nephrocalcinosis and urolithiasis in early childhood and renal failure that can occur at any age but is seen more often in adulthood. Bone disease is an inconsistent feature of each. Dent's disease is caused by mutations of the CLCN-5 gene with impaired kidney-specific CLC-5 chloride channel expression in the proximal tubule, thick ascending limb of Henle, and the collecting ducts. Resulting hypercalciuria and proximal tubule dysfunction, including phosphate wasting, are primarily responsible for the clinical manifestations. Low-molecular-weight proteinuria is characteristic. Definitive diagnosis is made by DNA mutation analysis. Primary hyperoxaluria, type I, is due to mutations of the AGXT gene leading to deficient hepatic alanine–glyoxylate aminotransferase activity. Marked overproduction of oxalate by hepatic cells results in the hyperoxaluria responsible for clinical features. Definitive diagnosis is by liver biopsy with measurement of enzyme activity, with DNA mutation analysis used increasingly as mutations and their frequency are defined.

Conclusion

These disorders of calcium urolithiasis illustrate the value of molecular medicine for diagnosis and the promise it provides for innovative and more effective future treatments.     

Intrathecal Ziconotide in the Treatment of Chronic Nonmalignant Pain: A Randomized,Double‐Blind,Placebo‐Controlled Clinical Trial

Objective. The safety and efficacy of intrathecal (IT) ziconotide was studied in a randomized, double‐blind, placebo‐controlled trial. Materials and Methods. Patients (169 ziconotide, 86 placebo) with severe chronic nonmalignant pain unresponsive to conventional therapy and a visual analog scale of pain intensity (VASPI score) ≥ 50 mm were treated over a 6‐day period in an inpatient hospital setting. Initial starting dose was 0.4 µg/hour and was titrated to analgesia or intolerance (maximum dose 7.0 µg/hour). The starting and maximum doses were reduced to 0.1 µg/hour and 2.4 µg/hour, respectively, due to adverse events (AEs). Results. The mean percent reduction in VASPI score from baseline was 31.2% and 6.0% for ziconotide‐ and placebo‐treated patients, respectively (p ≤ 0.001). During the initial titration phase, a significantly greater percentage of patients in the ziconotide group compared to the placebo group reported AEs, including abnormal gait, amblyopia, dizziness, nausea, nystagmus, pain, urinary retention, and vomiting. Conclusion. Ziconotide provided significant analgesia in patients for whom conventional therapy failed. However, there was a considerable incidence of ziconotide‐associated AEs due to the rapid titration and high doses administered.     

Parents' Views about Special Provision for their Child with Severe or Profound and Multiple Learning Difficulties

This paper reports on the findings of a research study, conducted via a postal questionnaire, which aimed to elicit the wishes, needs and satisfaction with special educational provision of parents of children with severe or profound and multiple learning difficulties. Parents' views regarding services received, type of housing and employment preferred for their child, present and future concerns are also reported. The results indicated that the majority of parents in the sample are generally satisfied with their child's current special school placement and do not want a change of placement. However, one in five parents did indicate a desire for a change of placement, with the preferred option being a special class in an ordinary school. A priority for their child's learning is communication skills. A desire for a high level of involvement in their child's education was indicated but, on the whole, parents did not achieve as high a level as they would wish. Parents were generally satisfied with services received but a significant proportion expressed a desire for additional services. In terms of the future, the majority of parents expect that their child is unlikely to live or work independently or semi-independently as an adult. The paper concludes by discussing ways of enhancing parents' involvement in the decision-making process regarding special provision for their child.     

Percutaneous management of lymphatic fluid collections

Eight lymphatic fluid collections were drained percutaneously. There were no immediate or late complications. Seven patients had follow-up; 1 required surgical drainage of a residual or recurrent lymphocele, and another had reaccumulated fluid in a lymphocele which was detected on autopsy. The remaining lymphatic collections responded to percutaneous drainage. Percutaneous drainage is safe and can be an effective tool in the management of lymphatic collections.     

Traumatic injuries associated with horseback riding.

BACKGROUND: According to the Center for Disease Control and Prevention (CDC), an estimated 30 million people ride horses each year in the United States. Horseback riding related injuries are common, with an estimated 50,000 emergency room visits annually. The popularity of recreational horseback riding has increased in South Florida and the incidence of associated traumatic injuries is a reflection of this. MATERIAL AND METHODS: Retrospective review of patients admitted to a state designated Level I trauma center that sustained horseback riding associated injuries between January 2000 and December 2003. Information extracted from the Trauma Center's data base included demographics, mechanism of injury and toxicology screening. RESULTS: During the review period, twenty-seven patients were identified. There were 12 men and 15 women. The average age was 36 years. The injuries occurred during pleasure riding in 23 patients and thoroughbred related activities in 4 patients. Multiple severe injuries were common and documented in 24 patients. All patients required hospitalization with an average stay of 5 days. Five patients had a positive toxicology screen on admission. No deaths were documented in this review. CONCLUSION: Horseback riding related injuries tends to be serious. Alcohol and recreational drugs may contribute to exacerbate the extent of these injuries. The use of proper protective equipment, instructions for safe riding, and discouraging drug and alcohol use during riding activities should be emphasized.     

Developing a Peer Review Process for Web-based Curricula

The World Wide Web creates new challenges and opportunities for medical educators. Prominent among these are the lack of consistent standards by which to evaluate web-based educational tools. We present the instrument that was used to review web-based innovations in medical education submissions to the 2003 Society of General Internal Medicine (SGIM) national meeting, and discuss the process used by the SGIM web-based clinical curriculum interest group to develop the instrument. The 5 highest-ranked submissions are summarized with commentary from the reviewers.