Search

Although myocardial perfusion positron emission tomography (PET), using either cyclotron-produced ammonia or generator-produced rubidium 82, has reported excellent diagnostic capabilities in the detection of coronary artery disease (CAD) in individual studies, the technique is not widely used in practice. This may be driven by cost and availability or by unawareness of performance. The purpose of our study was to conduct an evidence-based evaluation of PET in the diagnosis of CAD.We examined studies from January 1977 to July 2007 using MEDLINE and EMBASE. A study was included if it (1) used PET as a diagnostic test for CAD and (2) used catheter x-ray angiography as the reference standard (or =50% diameter stenosis). Analysis was performed on a subject and coronary territory level.Nineteen studies (1442 patients) met the inclusion criteria. On a patient level, PET demonstrated a sensitivity of 0.92 (95% confidence interval [CI]: 0.90-0.94) and specificity of 0.85 (CI: 0.79-0.90), with a positive likelihood ratio (LR+) of 6.2 (CI: 3.3-11.8) and negative likelihood ratio (LR-) of 0.11 (CI: 0.08-0.14). On a coronary territory level (n = 1130), PET showed a sensitivity of 0.81 (CI: 0.77-0.84) and specificity of 0.87 (CI: 0.84-0.90), with an LR+ of 5.9 (CI: 4.5-7.9) and an LR- of 0.19 (CI: 0.09-0.38).PET demonstrates excellent diagnostic properties in the diagnosis of CAD, especially at the patient level. The capabilities appear superior to those reported in meta-analyses for perfusion imaging with Tl-201 and sestamibi, or anatomical imaging with coronary MDCT angiography or MRA. Given that previous studies have found PET to be cost-effective and the current findings of excellent sensitivity and specificity, the modality should be more widely considered as an initial test in the diagnosis of CAD.

Pompe disease (PD), or glycogen storage disease type II, results from deficiency of acid α-glucosidase. Patients with infantile-onset PD die by early childhood if untreated. Patient survival has improved with enzyme replacement therapy. We report a case series of 8 patients with infantile-onset PD on enzyme replacement therapy with premature pubarche.

The existence of electromagnetic fields not generated by neuronal action or muscle stimulation remains controversial especially because they are difficulty to detect. We attempted to investigate the existence of electromagnetic fields associated with biologic systems using new image analysis techniques to analyze high-voltage electrophotography.Five energy practitioners (three males and two females) and five control subjects (four males and one female) participated in the study. Each practitioner had studied a formal training curriculum and was a professional energy practitioner. Images representing attempts of both energy practitioners and controls to elicit a change in electromagnetic emissions were captured by electrophotographic means. A statistical analysis on the comparison of "ON" vs. "OFF" states for the controls and practitioners in the study was made via digital representation of analogue images.Our interest was threefold: (1) to determine whether corona discharge patterns could be obtained and photographed and be reproducible; (2) to quantify some of the qualitative properties of the coronas; and (3) to determine if individuals can alter, at will, their electrophotographic images. We found a correlation between a change in the electromagnetic emissions for the body and the conscious desire of an energy practitioner to change this state. Analyses of individual finger coronas demonstrate statistically significant differences as analyzed by overall color changes and via analysis of individual sections of the various colors dominating the field. Control subjects were unable to produce statistically significant changes that were reproducible. Physiologic processes, such as changes in skin resistance, sweating, and surface blood constriction, have been suggested as an explanation of the colors and patterns that appear on the film in previous studies, but were not observed in this investigation.After controlling for the above variables and identifying reproducible and statistically significant changes, we believe the images created in our study represent the interaction of biologically generated electromagnetic fields interacting with the corona discharge created by the electrophotographic device.

Background and aims Advances in neonatal intensive care and nutrition support have increased survival of preterm infants, but the risk of compromised neurodevelopment is a concern. We evaluated parenteral nutrition (PN) as a heretofore unreported contributing factor to compromised neurodevelopment after preterm birth. Methods Neurodevelopment of preterm pigs delivered at 92% of gestation (representative of 32 week preterm infants) and provided PN or enteral nutrition (EN) for 10 days was assessed by observations of motor activity, sensory and cognitive skills, brain mass, magnetic resonance imaging, and cerebellar histology. Fluid volumes, energy, and nutrients were comparable. Results PN pigs grew slightly better than EN pigs, but had smaller brains (28 + 0.5 vs 32 + 0.6; p = 0.009), including the cerebellum, reduced motor activity (p = 0.005) and sensory responses (p Conclusions PN is essential for many preterm infant, and particularly those delivered earlier in gestation. The neurodevelopment delay caused by total PN independent of confounding variables (disease, inconsistent gestational ages,diverse genetics, different nutritional support and NICU protocols) is a novel and disturbing finding. The preterm pig is a translational animal model for investigating the relationship between nutrition support and neurodevelopment after preterm birth, improving PN solutions, and advancing neonatal intensive care.

Background: Support with a left ventricular assist device leads to normalization of left ventricular chamber geometry, regression of myocyte hypertrophy, alterations in left ventricular collagen content, and normalized expression of genes involved with excitation-contraction coupling in patients with heart failure. The objective of this study was to investigate the time course of these processes. Methods: Passive left ventricular pressure-volume relationships were obtained from explanted hearts of 19 patients with heart failure undergoing transplantation without left ventricular assist device support, 25 patients with heart failure supported before transplantation (duration of support ranging between 8 and 155 days), and 5 normal human hearts not suitable for transplantation. Left ventricular size was indexed by the volume at which left ventricular pressure reached 30 mm Hg. Left ventricular tissue samples were probed for sarcoplasmic endoreticular calcium adenosine triphosphatase 2a expression and processed for analysis of myocyte diameter and relative myocardial collagen content. Results: The volume at which left ventricular pressure reached 30 mm Hg was not significantly different between hearts without and with assist device support for less than 40 days. However, the volume at which left ventricular pressure reached 30 mm Hg in patients with assist devices supported for more than 40 days was significantly smaller than that of the hearts without assist devices but was larger than that of normal hearts. A similar pattern was observed for myocyte diameter. Sarcoplasmic endoreticular calcium adenosine triphosphatase 2a expression increased to normal levels by about 20 days of support with an assist device. Relative collagen content was significantly increased in hearts supported for more than 40 days. Conclusion: Maximum structural reverse remodeling by left ventricular assist devices is complete by about 40 days. Molecular reverse remodeling of sarcoplasmic endoreticular calcium adenosine triphosphatase 2a expression is quicker, being complete by about 20 days. (J Thorac Cardiovasc Surg 2001;121:902-8)

Vasodilatory hypotension requiring the administration of catecholamine pressors may occur following cardiopulmonary bypass. We investigated the hemodynamic response to arginine vasopressin (AVP) in 20 patients who developed vasodilatory hypotension after cardiac transplantation. In this cohort, AVP infusion (0.1 U/min) significantly increased mean arterial pressure and decreased norepinephrine requirements, allowing rapid discontinuation of norepinephrine infusions in 7 patients. Judicious use of this novel agent in appropriately selected patients may minimize end-organ sequelae of hypotension and high-dose catecholamine therapy.

Severe pulmonary hypertension and right-sided circulatory failure (RSCF) represent an increasing cause of morbidity and mortality in patients undergoing high-risk cardiac surgery. Increased pulmonary vascular resistance in the setting of cardiopulmonary bypass (CPB) may further lead to decreased blood flow across the pulmonary vascular bed; thereby decreasing left ventricular filling and cardiac output. Current management techniques for RSCF include both nonspecific vasodilator and inotropic agents (often limited by systemic hypotension) and the placement of right ventricular assist devices (associated with increased perioperative morbidity). Inhaled nitric oxide (NOi) represents a novel, specific pulmonary vasodilator that has been proven efficacious in these clinical settings. We evaluated 34 patients in 38 operations who underwent cardiac surgery at Columbia Presbyterian Medical Center, and who received NOi (20 ppm) through a modified ventilatory circuit for hemodynamically significant elevations in pulmonary vascular resistance. Nine patients underwent cardiac transplantation, three patients bilateral lung transplantation, 16 patients left ventricular assist device placement and 10 patients routine cardiac surgery. Patients receiving NOi exhibited substantial reductions in mean pulmonary artery pressure (mPAP) (34.6 ± 2.0 to 26.0 ± 1.7 mmHg, p < 0.0001), with improvements in systemic hemodynamics, mean arterial pressure (68 ± 3.1 to 75.9 ± 2.0 mmHg, p = 0.006). In five cases, patients could not be weaned from CPB until NOi was administered. Patients were maintained on NOi from 6 to 240 h postoperatively (median duration 36 h). Inhaled NO induces substantial reductions in mPAP and increases in both cardiac index and systemic blood pressure in patients displaying elevated pulmonary hemodynamics after high-risk cardiac surgery. NO is, therefore, a useful adjunct in these patients in whom acute pulmonary hypertension threatens right ventricular function and hemodynamic stability.

Background . Pulmonary vascular resistance is often elevated in patients with congestive heart failure, and in those undergoing left ventricular assist device (LVAD) insertion, it may precipitate right ventricular failure and hemodynamic collapse. Because the effectiveness of inotropic and vasodilatory agents is limited by systemic effects, right ventricular assist devices are often required. Inhaled nitric oxide (NO) is an effective, specific pulmonary vasodilator that has been used successfully in the management of pulmonary hypertension. Methods . Eleven of 23 patients undergoing LVAD insertion met criteria for elevated pulmonary vascular resistance on weaning from cardiopulmonary bypass (mean pulmonary artery pressure >25 mm Hg and LVAD flow rate −1 · m −2 ) and were randomized to receive either inhaled NO at 20 ppm (n = 6) or nitrogen (n = 5). Patients not manifesting a clinical response after 15 minutes were given the alternative agent. Results . Hemodynamics for the group at randomization were as follows: mean arterial pressure, 72 ± 6 mm Hg; mean pulmonary artery pressure, 32 ± 4 mm Hg; and LVAD flow, 2.0 ± 0.3 L · min −1 · m −2 . Patients receiving inhaled NO exhibited significant reductions in mean pulmonary artery pressure and increases in LVAD flow, whereas none of the patients receiving nitrogen showed hemodynamic improvement. Further, when the nitrogen group was subsequently given inhaled NO, significant hemodynamic improvements ensued. There were no significant changes in mean arterial pressure in either group. Conclusions . Inhaled NO induces significant reductions in mean pulmonary artery pressure and increases in LVAD flow in LVAD recipients with elevated pulmonary vascular resistance. We conclude that inhaled NO is a useful intraoperative adjunct in patients undergoing LVAD insertion in whom pulmonary hypertension limits device filling and output.

Objective The h -index was introduced as a means of quantifying the contribution a researcher makes to the scientific literature. We evaluated the h -index for academic neurosurgeons to assess the various methods of calculation and to determine whether the h -index can be used to differentiate groups of individuals by various classifications. Methods The h -index was calculated for all neurosurgeons from 10 institutions ranked highly by 2012 U.S. News & World Report plus the authors' institution via Scopus. The h -index also was calculated manually to evaluate its accuracy. The average h -index was calculated for groups on the basis of sex, academic rank, years in practice, institution, and subspecialty. Cumulative and mean h -indices were calculated for each department. Results The median h -index for the 188 neurosurgeons was 16 (mean, 19.71; range, 0–61). There was a positive association between the h -index, academic rank, and years posttraining. There was a significant difference between the "manually calculated" and automated h-indices, particularly for more senior physicians. The difference in h -index between men and women was not statistically significant. Among subspecialties, vascular surgeons had the greatest average h -index and general neurosurgeons had the lowest. There were significant shifts in departmental rankings when the cumulative or mean departmental indices were compared with the U.S. News & World Report rankings. Conclusion Application of the h -index as a bibliometric in neurosurgery can distinguish academic productivity on the basis of academic rank, years posttraining, and neurosurgical subspecialties. The application of the h -index to compare departments is problematic and, at this time, not reliable.

Axenfeld-Rieger syndrome (ARS) is a genetic disorder representing a disease spectrum resulting from neural crest cell maldevelopment. Glaucoma is a common complication from the incomplete formation of the iridocorneal angle structures. Neural crest cells also form structures of the forebrain and pituitary gland, dental papillae, aortic arch walls, genitalia, and long bones; therefore, patients with ARS manifest a wide range of systemic findings. To our knowledge, detailed magnetic resonance imaging findings have not been previously reported. We report a case of a 19-month-old Indian male diagnosed with ARS with emphasis on magnetic resonance imaging findings of the globes, brain, teeth, and skull base.

Objective: To determine if MRI is as effective as CT in identification of calcified subependymal nodules in tuberous sclerosis (TS) patients, so that the number of CT scans that TS patients undergo may be able to be reduced, leading to less radiation exposure and less cost. Background CT has been used to look for calcifications in TS patients, especially if they have enlarging subependymal nodules concerning for subependymal giant cell astrocytomas. However, CT has been found to be a source of significant radiation, and MRI techniques have advanced. Design/Methods: TS patients who underwent both a CT and MRI within a 120 day period were evaluated. CT and MR studies from the same patient were compared. CT was considered the gold standard in identification of calcification. Calcification on CT was considered a true positive (TP). Results: Neuroimaging from 9 patients has been reviewed. Patient ages ranged from 2 months to 7 7/12 years, with an average of 3.9 years. Only 2 patients had SWI sequences, which was a limitation of this study. Fifty-five subependymal nodules were identified. MRI overall detected 52 of 55 lesions. The sensitivity for detecting subependymal nodules was 94.5% for T2-weighted imaging, 85% for B0 sequences, and 87% for SWI. The overall sensitivity of CT for detecting subenpendymal nodules was 94.5%; however, most of the lesions were calcified. The sensitivity of CT for uncalcified subependymal nodules was 25%. Among the MRI sequences, the sensitivity for detecting calcifications on T2-weighted sequences was 78%, B0 sequences was 82%, and SWI was 87%. Conclusions: CT is more sensitive than MRI at detecting calcified subependymal nodules. However, it is not sensitive for uncalcified nodules. Traditional MRI (without SWI) tended to underestimate calcified subependymal nodules. However, addition of SWI, which appeared to be the most sensitive MRI sequence to calcification, may allow closer approximation to CT findings. Disclosure: Dr. McGregor has received royalty payments from MedHumor Publishing. Dr. Caron has nothing to disclose. Dr. Perkins has nothing to disclose. Dr. Wheless has received personal compensation for activities with Abbott, UCB, GSK, Novartis, Ortho-McNeil, Cyberonics, Abbott, Cyberonics, Inc., Novartis, Ovation Pharmaceuticals, Marinus Pharmaceuticals, Questcor, Valeant, Pfizer Inc as a consultant and/or participant on an advisory board. Dr. Wheless has received research support from Abbott Laboratories, Cyberonics, Inc., Ortho-McNeil Pharmaceuticals, Novartis, UCB Pharma and Ovation Pharmaceauticals. Dr. Choudhri has nothing to disclose.

To identify the sources of electromagnetic interference (EMI) that may alter the performance of implanted cardiac devices and develop strategies to minimize their effects on patient hemodynamic status.Since the development of the sensing demand pacemaker, EMI in the clinical setting has concerned physicians treating patients with such devices. Implanted cardiovertor defibrillators (ICDs) and ventricular assist devices (VADs) can also be affected by EMI.All known sources of interference to pacemakers, ICDs, and VADs were evaluated and preventative strategies were devised.All devices should be thoroughly evaluated before and after surgery to make sure that its function has not been permanently damaged or changed. If electrocautery is to be used, pacemakers should be placed in a triggered or asynchronous mode; ICDs should have arrhythmia detection suspended before surgery. If defibrillation is to be used, the current flow between the paddles should be kept as far away from and perpendicular to the lead system as possible. Both pacemakers and ICDs should be properly shielded if magnetic resonance imaging, positron emission tomography, or radiation therapy is to be used. The effect of EMI on VADs depends on the model. Magnetic resonance imaging adversely affects all VADs except the Abiomed VAD, and therefore its use should be avoided in this population of patients.The patient with an implanted cardiac device can safely undergo surgery as long as certain precautions are taken.

Left ventricular assist devices (LVAD) are implantable mechanical blood pumps providing circulatory assistance for patients in heart failure, and are currently being investigated as a long‐term alternative to cardiac transplantation. While effective in short term use as a bridge to transplantation, the durability of the device for extended use has yet to be demonstrated. To prospectively follow the mechanical status of the devices, biweekly transabdominal acoustic readings from a standard microphone and accelerometer are obtained. Time‐domain analysis of the recordings allows the timing of ejection (device systole) and passive filling (device diastole) to be measured. Ejection duration was measured at 240 ms in 11 new devices and exceeded 300 ms in two aging devices which subsequently failed within 3 weeks of measurement. Frequency‐domain analysis showed the presence of a 230‐Hz signal in both failing devices, possibly indicative of bearing wear within the motor. In addition, a 50‐Hz signal present in all properly functioning devices was missing in one of the devices which failed. Acoustical analysis will play a vital role in the continuing care of LVAD patients and will allow a more rapid and noninvasive method of assessing device status.