Relative contribution of vitamin D deficiency to subclinical atherosclerosis in Indian context: Preliminary findings.

ABSTRACT: Asian Indians have a genetic predisposition to atherothrombotic risk. common carotid intima-media thickness (CCIMT) measured by ultrasound is a quantitative marker for atherosclerotic burden and a derived variable, that is, "CCIMT statistical Z-score (Z-score)" is useful for better quantification. The association between vitamin D deficiency and atherosclerosis is inconclusive. Since, vitamin D deficiency is highly prevalent in India, there is a need to study its relative contribution to subclinical atherosclerotic burden.This prospective cross-sectional study (n = 117) in apparently healthy individuals aged 20 to 60 years sought to identify the determinants of CCIMT Z score with CCIMT measured by "echo-tracking" method. A multivariable linear regression analysis was done with CCIMT Z score as dependent variable and the following as independent variables: age, body mass index, waist-to-height ratio, total cholesterol to HDL ratio (TC-HDL ratio), serum vitamin D3 levels (ng/mL), sex, diabetes mellitus, current cigarette smoking status. A diagnostic prediction model was also developed with a threshold value of 1.96 for CCIMT Z score.The mean (SD) for calendar age (y) was 40 (8). There were 26 (22.22%) individuals in sample with CCIMT Z score ≥1.96 (advanced stage) of whom 14 (23.33%) were <40 y (n = 60). The mean score was 1.28 (90th percentile) in the entire sample. Vitamin D3 deficiency with a mean (SD) blood level (ng/mL) of 14.3 (6.4) was noted and prevalence of deficiency was 81%. The final model wasCCIMT Z-score = 0.80 +  (0.841 × current smoking = 1) + (0.156 × TC-HDL ratio) - (0.0263 × vitamin D3 blood level in ng/mL).The decreasing order of association is smoking, TC-HDL ratio, and vitamin D3. With the model, likelihood ratio (95% CIs) was better for positive test 3.5 (1.23-9.94) than that for a negative test 0.83 (0.66-1.02).Internal validation with Bootstrap resampling revealed stability of baseline diagnostic variables.There is substantial subclinical atherosclerotic burden in Indian setting with independent contribution by vitamin D deficiency. The model is valuable in "ruling-in" of the underlying advanced atherosclerosis. The study is limited by convenient sampling and lack of external validation of the model.

Use of Common Carotid Intima-Media Thickness Measured by Ultrasound Echo-Tracking in Cardiovascular Risk Stratification Before Noncardiac Surgery in Low-Risk Category: A Research Idea.

Preoperative cardiac risk stratification algorithms typically use a Bayesian approach to identify a low-risk category group for which the outcome is unlikely to be improved by further testing. This report suggests evaluating common carotid intima-media thickness (CCIMT) as measured by ultrasound to determine whether it strengthens and optimizes perioperative Bayesian risk indices. The idea proposes to use CCIMT Z score and vascular age to quantify atherosclerotic burden. CCIMT may be useful as part of shared decision-making for perioperative care. A website (www.suhitam.com/vascularage) designed by one of the authors (S.M.) is a useful resource.).

Up/down conversion luminescence and charge compensation investigation of Ca0.5Y1-x(WO4)2:xLn(3+) (Ln=Pr, Sm, Eu, Tb, Dy, Yb/Er) phosphors.

Microstructures of Ca0.5Y(1-x)(WO4)2:xLn(3+) (Ln=Pr, Sm, Eu, Tb, Dy, Yb/Er) phosphors were prepared via the solid-state reaction method. X-ray diffraction, scanning electron microscopy and photoluminescence were used to characterize the prepared phosphor samples. The results reveal that the phosphor samples have single phase scheelite structures with tetragonal symmetry of I41/a. The down/up conversion photoluminescence of the Ca0.5Y(1-x)(WO4)2:xLn(3+) (Ln=Pr, Sm, Eu, Tb, Dy, Yb/Er) phosphors properties reveal characteristic visible emissions. The energy transfer process, fluorescence lifetime and color coordinates are discussed in detail. Furthermore, the phosphor Ca0.5Y(1-x)(WO4)2:xPr(3+) co-doped with alkali chlorides shows the enhancement of luminescence, which was found in the sodium chloride co-doped powder phosphor. The photometric characteristics indicate the suitability of the inorganic powder phosphors for solid-state lighting and display applications.

Efficacy and outcomes of perioperative anesthetic management of extracranial to intracranial bypass for complex intracranial aneurysm in the absence of advanced neurological monitoring.

BACKGROUND AND AIMS: Anesthetic management of extracranial to intracranial (EC-IC) bypass for complex intracranial aneurysms is challenging as the goals involve balancing the cerebral perfusion during parent artery clamping and avoiding factors that predispose to rupture of the unsecured aneurysm. There is very sparse literature available on anesthetic management for this procedure. MATERIALS AND METHODS: A retrospective review of the records of 20 patients undergoing EC-IC bypass was performed with an objective of assessing the efficacy and outcomes of anesthetic management in the absence of advanced neurological monitoring. RESULTS: A total of 20 patients underwent EC-IC bypass as an adjunct cerebral revascularization in the management of complex intracranial aneurysms. Intraoperatively normotension and normocarbia were maintained. During the EC-IC bypass, when the temporary clamp was applied, mild hypertension (increase from baseline by 20%) and hypervolemia (central venous pressure increased to 12 mmHg) were maintained. Cerebral protection during temporary clipping of intracranial vessel was provided using moderate hypothermia to 34°C and intravenous thiopentone. Temporary clip time ranged from 15 min to 54 min (mean-25 min). All patients except one were extubated post-operatively (19/20 = 95%). None of the patients had rupture of aneurysm in the peri-operative period. Three patients developed neurologic events (3/20 = 15%). One patient had cerebral vasospasm and two patients developed cerebral infarction. Two patient subsequently improved and one succumbed to the neurological deterioration (mortality 1/20 = 5%). CONCLUSION: Adherence to the principal goals for the procedure, avoidance of hemodynamic fluctuations such as hypotension and hypertension, maintenance of normocarbia, and cerebral protection, result in favorable neurological outcome even in the absence of advanced neuromonitoring.

Unilateral neurogenic pulmonary oedema: An unusual cause for post-operative respiratory dysfunction following clipping of ruptured intracranial aneurysm.

A variety of central nervous system lesions like stroke, subarachnoid haemorrhage, trauma and seizure activity can result in neurogenic pulmonary oedema (NPE). Unilateral neurogenic pulmonary oedema is very rare. There are no reports of unilateral NPE with aneurysmal vasospasm. We present the case of a 55-year-old female who developed respiratory distress with unilateral pulmonary oedema and mild left ventricular dysfunction in the context of postoperative cerebral vasospasm following clipping of ruptured intracranial aneurysm. Neurogenic pulmonary oedema should always be in the differential diagnosis when patients with presumed neurogenic pathology develop respiratory compromise. The diagnosis of unilateral neurogenic pulmonary oedema requires a high index of suspicion. Early initiation of supportive treatment results in good outcome.

Development and validation of predictors of respiratory insufficiency and mortality scores: simple bedside additive scores for prediction of ventilation and in-hospital mortality in acute cervical spine injury.

BACKGROUND: Numerous studies have developed a "severity score" or "risk index" for mechanical ventilation and mortality, but there are few to predict outcomes for cervical spine injury (CSI) patients. Our objective in this study was to develop a simple bedside additive predictive score for requirement for ventilation and early in-hospital mortality for patients with CSI. METHODS: Multivariate logistic regression analysis of the data obtained from 101 patients (development set) after surgical stabilization of traumatic CSI was performed to identify independent predictors of the need for mechanical ventilation and of early in-hospital mortality. Predictors of respiratory insufficiency and mortality (PRIM) scores were developed separately for ventilation and mortality by using the coefficients of the logistic regression model. The model was validated using the receiver operating characteristics curve to test its discriminatory ability and by comparing the predicted and observed outcomes. Validation was performed on an independent data set of 87 consecutive patients (validation set) with traumatic acute CSI. RESULTS: Mechanical ventilation was required in 16.8% of the patients, and the in-hospital mortality rate was 17.8% in the development set. Independent risk factors for mechanical ventilation were severe injury (American Spinal Injury Association Impairment Scale Grades A and B), breath-holding time, pulmonary infection, hemodynamic instability, and progressive neurologic deterioration. Scores of 15, 20, 25, 25, and 15 were assigned to these variables, respectively. Independent predictors of death were severe injury (American Spinal Injury Association Impairment Scale Grades A and B), hemodynamic instability, progressive neurologic deterioration, and mechanical ventilation. The scores assigned for each of the variables were 20, 20, 40, and 20, respectively. The PRIM scores for mechanical ventilation and mortality had excellent discrimination (area under receiver operating characteristics curve >0.75). There was good correlation between predicted and observed outcomes in the development set and the validation set. CONCLUSION: PRIM scores enable accurate prediction of individual patient risk of need for mechanical ventilation and in-hospital mortality in association with acute CSI.

Train of four responses in paretic limbs.

Quadriplegic patients pose difficulty for neuromuscular monitoring owing to nonavailability of accessible normal muscle. It is known that train of four responses (T4/T1 ratio) was exaggerated in paretic limbs. However, no studies have quantified the exaggeration at different degrees of block. This study was undertaken to quantify the exaggeration of train of four responses in paretic limbs with increasing levels of block after the administration of neuromuscular blocking drugs. Nine patients with normal motor power (group N) and 9 patients with paraplegia (group P) were studied. The mean difference in T4/T1 ratio (95% CI) between upper limb and lower limbs in normal group at T4/T1 81-90, T4/T1 71-80, T4/T1 51-70, T4/T1 31-50, and T4/T1 0-30 were 8.9 (0.8 to 16.9), 11.6 (3.8 to 19.5), 5.1 (-8.6 to 18.8), 7.6 (-6.8 to 21.9), and 3.8 (-0.9 to 8.5) and in paraplegic group, 14.5 (7.6 to 21.5), 25.1 (13.9 to 36.4), 35.6 (27.5 to 43.7), 29.1 (15.4 to 42.7), and 60 (39.4 to 80.7), respectively. There was a statistically significant difference in the train of four responses between normal and paretic limbs at all levels of block except at T4/T1 81-90. There was a significant positive correlation between difference in the T4/T1 ratio between the upper and lower limbs and intensity of block in the paraplegic group but no correlation in the normal group. The observation that T4/T1 ratio enhancement in denervated limbs is dependent on depth of neuromuscular block may have future implications for monitoring and reversal of neuromuscular block in this patient population.

Intense cardiac troponin surveillance for long-term benefits is cost-effective in patients undergoing open abdominal aortic surgery: a decision analysis model.

BACKGROUND: Strategies to limit adverse cardiac events after vascular surgery continue to evolve. Early recognition and treatment of myocardial ischemia may be a key to improving postoperative survival rates. Cardiac troponin I (cTnI) screening is an effective means of surveillance for postoperative myocardial ischemic injury and has long-term prognostic value. METHODS: We designed a Markov-based decision analysis model to determine the cost-effectiveness of routine surveillance with cTnI on postoperative Days 0, 1, 2, and 3, with an aim to institute tight heart rate control (60-65 bpm) with close monitoring and coronary care in the intensive care unit for 5 days in patients with cTnI >1.5 ng/mL. The key input variables obtained from published literature were as follows: probability of myocardial infarction, 0.049; cost of cTnI surveillance, $357; cost and efficacy of interventions, $13,145 and 0.55, respectively. The time horizon was lifetime and the target population being individuals aged 65 yr (median) undergoing elective open abdominal aortic surgery. The perspective for analysis was third-party payer. RESULTS: The incremental cost-effectiveness ratio for cTnI surveillance was $12,641 per quality-adjusted life year compared with standard care without cTnI surveillance. During one-way sensitivity analysis, probability of myocardial infarction and efficacy of interventions were found to influence the cost-effectiveness. Multivariate sensitivity analysis with second-order Monte Carlo simulation revealed that cTnI surveillance was favored in 90.75% of simulations at a commonly used threshold of $50,000 per quality-adjusted life year. CONCLUSIONS: In patients presenting for elective open abdominal aortic surgery, intensive surveillance with cTnI and early institution of aggressive beta-blockade is cost-effective.

Should troponin and creatinine kinase be routinely measured after vascular surgery?

The current guidelines for the evaluation and prediction of adverse cardiovascular events (CVEs) following vascular surgery in high-risk patients recommends serial electrocardiograms (ECGs) but not biomarkers such as cTn-I and CK-MB. The objective of this study was to determine whether biomarkers should be routinely measured in high-risk patients undergoing vascular surgery. A multicenter, prospective study with investigators blinded to core laboratory results was conducted. cTn-I and CK-MB were obtained on the day of surgery, as well as 24 hours, 72 hours and 120 hours after surgery, 24 hours prior to planned hospital discharge and at the onset of symptoms of a suspected CVE. The CVE was adjudicated by an endpoint committee using ECG, biomarker and symptoms data and was defined as cardiac death or myocardial infarction (MI) occurring up to 30 days after surgery. A total of 784 patients, with a mean age of 70.1 (SD +/- 9.8), underwent vascular surgery. Of the 83 patients with a CVE, cTn-I was positive in 42 and CK-MB was positive in 29 on or before the day of the CVE. The number of patients not classified as having a CVE but positive for elevation of cTn-I or CK-MB was 64 and 20, respectively. cTn-I was more sensitive than CK-MB (50.6% versus 34.9%) for predicting a CVE. The optimum time for measuring cTn-I after surgery with the highest positive predictive value was 24 hours. In conclusion, these data support routine serial measurement of cTn-I after vascular surgery.

Usefulness of routine preoperative testing: a prospective single-observer study.

STUDY OBJECTIVE: The purpose of this study is to determine whether routine preoperative testing has a usefulness not previously recognized in a small preliminary study to decide if such a hypothesis might be worthy of testing in a larger study. DESIGN: Single-observer, prospective, observational study. SETTING: Tertiary-care referral center in South India that performs 11 preoperative tests on each patient. PATIENTS: One hundred twenty-seven adult patients scheduled for elective neurosurgery. INTERVENTIONS: Patients were studied to determine whether outcome was influenced by laboratory tests, which were either indicated by health history elicited by a computerized rule-based questionnaire or unindicated by patient history. MEASUREMENT AND MAIN RESULTS: Of the 1395 tests performed preoperatively, 513 (36.8%) were indicated and 882 (63.3%) were unindicated. Of 513 indicated tests, 17 (3.3%) prompted changes in patient care; 8 (0.91%) of 882 unindicated tests (P < .001) prompted changes in care. All patients with anemia, significant electrocardiographic abnormalities, or HIV infection were detected by the computerized questionnaire. Among the changes in care prompted by unindicated tests, 4 patients received diabetic therapy or counseling, and 4 patients with abnormal silhouettes on chest radiograph had nonbeneficial echocardiography. Only screening for diabetes seemed to have usefulness as a routine preoperative test in this patient population. CONCLUSION: Although the incidence of unindicated preoperative screening tests is still more than 50%, no previously unidentified benefit was found to support this persistence of unwarranted testing. The limited number of patients in this study necessitates a larger study to ensure greater certainty before such a recommendation is made to the public. If similar results in another but larger study involving similar design, simple changes in the system of preoperative care may save the health care system the considerable expense of unwarranted testing.