Experimental and clinical assessment of mitral annular area and dynamics: what are we actually measuring?

The mitral annulus is an essential, dynamic, and tightly coupled component of the mitral valve/left atrial/left ventricular complex that aids in effective and efficient valve closure and unimpeded left ventricular filling. Although the dynamic nature of mitral annular motion has been studied carefully for more than 30 years, accurate measurement of mitral annular area and motion continues to be a challenge for physiologists and clinicians alike. Roentgenographic ciné imaging of radiopaque markers, sonomicrometry, magnetic resonance imaging, and two-dimensional echocardiography have all been used to evaluate mitral annular area and dynamics, yet widely disparate measurements abound. Paradoxically, newer three-dimensional transesophageal echocardiographic findings may have added to this miasma. To explore the variability of these measurements, we reviewed our experimental data as well as clinical and experimental observations reported in the literature to clarify what we are actually measuring and perhaps explain the reported disagreement. The objective was to shed some light on the possible reasons for these discordant findings.

Robotic recovery of highly radioactive resin.

As the ALARA coordinator at Waterford 3 Nuclear Steam Electric Station, I have seen radiological challenges in many forms. Some are handled as routine with little effort, while others can severely challenge even the finest Health Physics staff. One such event occurred on 26 December 1997, during a routine recirculation of the Spent Resin Tank, when contents of an unknown origin spilled from the tank. Technicians performing initial actions to contain the spill monitored radiation levels of 5-20 rem h21 (50-200 mSv) at waist level. Based on photographs and visual accounts it was estimated that approximately 30-40 ft3 (0.57-1.12 m3) of resin had spilled into the pump room. A sample of the resin indicated that dose rates at the floor would exceed 100 rem h21 (1 Sv h21). It was clear, given the volume of material spilled and dose rates in the room, that robots would be required for any type of recovery effort. This presented another problem in that Waterford 3 did not own a robot, and we had no experience in this area.

Limited value of preoperative cervical vascular imaging in patients with velocardiofacial syndrome.

The purpose of this two-part study was to evaluate the safety of surgical management of speech production disorders in patients with velocardiofacial syndrome without preoperative cervical vascular imaging studies. Anomalous internal carotid arteries have been shown to be a frequent feature of velocardiofacial syndrome. These vessels pose a potential risk for hemorrhage during velopharyngeal narrowing procedures. Magnetic resonance angiography, and other forms of cervical vascular imaging studies such as computerized tomography, have been advocated as aids to surgery by defining the preoperative vascular anatomy. However, it remains unclear whether these studies alter either the conduct or outcome of operations on the velopharynx. In the first part of this study, we reviewed the charts and videonasendoscopic evaluations of 39 consecutive patients with confirmed or suspected velocardiofacial syndrome who underwent sphincter pharyngoplasty or pharyngeal flap from 1978 to 1996. The charts were reviewed to determine (1) the frequency of identification of abnormal pharyngeal pulsations; (2) whether such pulsations affected the conduct of the operative procedure; and (3) whether the presence of pulsations affected surgical morbidity and/or surgical outcome. None of the patients underwent any type of cervical vascular imaging study. In the second part of this study, we surveyed plastic surgeons with numerous years of experience participating on cleft-craniofacial teams, to ascertain practice patterns relating to the management of patients with velocardiofacial syndrome. The questions related specifically to the surgeons' behavior in relation to angiography and their awareness of any cases of surgical morbidity related to the cervical vascular system in patients with velocardiofacial syndrome. We were interested in discerning both how commonly this situation arises clinically and the distribution of the various types of operative procedures in common use. Of our 39 patients, 10 patients (26 percent) had detectable pulsations on preoperative nasendoscopy. Of these, five patients underwent sphincter pharyngoplasty and five underwent pharyngeal flap procedures. Preoperative instrumental and intraoperative clinical assessment of pulsatile vessels allowed velopharyngeal reconstruction in all patients without surgical morbidity. Results of the questionnaire indicated that most cleft surgeons do not routinely order cervical vascular imaging studies for all of their patients with velocardiofacial syndrome. About half of the respondents indicated that their operative approach was influenced by information obtained from angiographic studies. None of the surgeons queried were aware of any cases of surgical morbidity related to the cervical vascular system in patients with velocardiofacial syndrome. Nearly 50 percent of surgeons use pharyngeal flap procedures most frequently, whereas 22 percent of surgeons use sphincter pharyngoplasty most frequently. Results of this study support the safety of sphincter pharyngoplasty or pharyngeal flap procedures in patients with velocardiofacial syndrome without preparatory angiography. These procedures can be performed safely, even in patients having aberrant velopharyngeal pulsations. Given the market cost of magnetic resonance angiography ($1600), one must question the cost-efficacy of magnetic resonance angiography for routine use in the velocardiofacial syndrome population.

Randomized, prospective assessment of bioprosthetic valve durability. Hancock versus Carpentier-Edwards valves.

BACKGROUND: Although the major limitation of porcine valves is their finite durability, no controlled clinical data exist regarding the relative durability of the two porcine bioprostheses implanted most commonly today, the Carpentier-Edwards (C-E) and Medtronic Hancock I (H) valves. METHODS AND RESULTS: To assess this question, 174 patients undergoing aortic (AVR) or mitral (MVR) valve replacement with a bioprosthesis between March 1980 and March 1982 were randomized to receive either a C-E or a H valve. There were 102 AVRs (54 C-E and 48 H) and 74 MVRs (39 C-E and 35 H). For both the AVR and MVR cohorts, the average patient age was 58 +/- 14 years (+/- SD). The male/female ratio was 2.2:1 for AVR and 0.57:1 for MVR. Clinical follow-up was undertaken periodically; the most recent follow-up closing interval was July through October 1992, and current follow-up was 96% complete. Cumulative follow-up totaled 1369 patient-years (mean, 7.7 +/- 3.6 years; median, 9.1 years; maximum, 12.0 years). The main focus of this analysis was bioprosthetic durability, using the AATS/STS guidelines defining "Structural Valve Deterioration" (SVD). Multivariate analysis revealed that (younger) age was the only significant (P = .024) independent predictor of SVD. Valve manufacturer (C-E versus H) and valve site (aortic versus mitral) did not emerge as significant independent risk factors for SVD. Actuarial rates (Cutler-Ederer) expressed as percent free of SVD (+/- SEM) at 10 years (n = number of patients remaining at risk) were 71 +/- 7% and 59 +/- 9% for the C-E (n = 26) and H (n = 17) groups, respectively, for the AVR cohort; for the MVR cohort, these estimates were 60 +/- 10% (n = 12) and 72 +/- 10% (n = 11), respectively, but these differences were not statistically significant (P = NS, Lee-Desu). CONCLUSIONS: After 10 years, there was no statistically significant difference in durability or other valve-related complications between the H and C-E aortic or mitral valves. Based on current information, the choice of a porcine bioprosthesis should be based on factors other than durability, including ease of implantation, hemodynamic performance, and cost.

Therapeutic efficacy of intraaortic balloon pump counterpulsation. Analysis with concurrent "control" subjects.

During a 7-year period, intraaortic balloon pumping (IABP) was attempted in 319 cardiac surgical patients. The indications for IABP were stringent and consisted of unsuccessful discontinuation of cardiopulmonary bypass (39%), anticipated failure (40%) to wean from cardiopulmonary bypass, postoperative low cardiac output, or intractable ventricular tachyarrhythmias (15%). IABP support was successfully instituted in 280 patients and was unsuccessful in 39 patients ("controls"). These two groups were comparable except for an older mean age and a higher ejection fraction in controls. Operative mortality rates were 45% and 62% for IABP and control groups, respectively (p = 0.077). This difference was most evident in coronary artery bypass patients, in whom the decision to institute IABP counterpulsation was made intraoperatively before attempted discontinuation of cardiopulmonary bypass. Two years postoperatively the actuarial survival rate was 45 +/- 3% for the IABP group and 23 +/- 9% for the control group (p = 0.006). After exclusion of operative deaths, however, these survival rates were 81 +/- 3% and 60 +/- 20%, respectively (p = NS). The average hospital charge incurred by IABP patients was threefold greater than that of uncomplicated cardiac surgical procedures. We conclude that IABP counterpulsation is therapeutic for some cardiac surgical patients, but its benefits cannot be defined easily. The long-term survival rates for patients with advanced disease requiring IABP support perioperatively are poor and warrant continued development of more effective methods of mechanical circulatory assistance and heart replacement.

Children's services and Title XX from a national perspective.

The Social Security Act's Title XX, which became law in 1975, has brought many changes in social services. This article examines problems, confusions and opportunities that accompany the new regulations.

Simplified field assessment of nutritional status in early childhood: practical suggestions for developing countries.

This paper proposes a simple and inexpensive method for the field assessment of certain objective indicators of nutritional status in children of preschool age. It emphasizes the need for statistically valid sample selection and presents a design for randomly selecting 30 children from each of 30 village sites in each region for which quantitative inferences are to be made, the main purpose being to estimate the prevalence of protein-energy undernutrition and anaemia. The need to train indigenous paraprofessional workers as assessors and periodically to control their accuracy is stressed. The method used is limited to an estimate of the location and magnitude of common childhood malnutrition and it is recommended that it be supplemented by detailed ecological analysis to determine causal factors and propose remedial action.