Screening for deep venous thrombosis after idiopathic scoliosis surgery in children: a pilot study

Background: Venous thrombosis remains an uncommon disorder in childhood. However, the incidence appears to be increasing for a multitude of reasons. The aim of the study was to detect asymptomatic deep venous thrombosis and prothrombotic diseases in nonsyndromic children undergoing scoliosis surgery. Methods: A prospective study including forty successive teenagers scheduled for posterior spinal fusion. Patients with scoliosis with a history of hemoglobinopathies, cardiac defects, blood clots, early onset osteoporosis, as well as patients with skeletal dysplasias and nonskeletal dysplastic syndromic entities have been excluded. The protocol was designed for active screening of deep venous thrombosis using color Doppler ultrasonography on a day before surgery and repeated on the 3rd, 7th and 15th day postoperatively. Evaluation of prothrombotic disorders included antithrombin and protein C activities, and total protein S antigen level. Results: No patient has manifested clinical symptoms of venous thrombosis in our study. Preoperative Doppler and ultrasound examinations were normal in all patients. Although repeated Doppler ultrasonography demonstrated a transient small clot in two patients. Congenital antithrombin deficiency of 5% has been observed in one child only, without the development of deep venous thrombosis. Conclusion: Thromboembolic event seems to be rare after scoliosis surgery. Prophylaxis for venous thrombosis should not be recommended in such patient. But, larger series are required to confirm such results.     

Efficacy of Ascorbic Acid,N‐Acetylcysteine,or Combination of Both on Top of Saline Hydration versus Saline Hydration Alone on Prevention of Contrast‐Induced Nephropathy: A Prospective Randomized Study

Background

Antioxidant drugs such as N‐acetylcysteine (NAC) and ascorbic acid have been evaluated in interventional studies to prevent contrast‐induced nephropathy (CIN), however, there are limited data on comparing either or both, with background of standard intravenous saline hydration versus the standard intravenous saline hydration alone in preventing CIN.

Methods

We conducted a single‐center randomized trial among patients undergoing coronary angiography or percutaneous coronary intervention who had serum creatinine ≥ 1.3 mg/dL or were on diabetes mellitus medication. Eligible patients were randomly assigned to one of the following 4 groups: (1) NAC, (2) ascorbic acid, (3) combination of both drugs, and (4) control group. Additionally, all the groups received the standard intravenous saline hydration. Creatinine was measured 4–5 days after procedure.

Results

A total of 243 patients were randomized; 62 to NAC, 57 to ascorbic acid, 58 to both drugs, and 66 to placebo. The development of 0.5 mg/dL absolute increase of serum creatinine, 25% relative decrease of creatinine clearance, or either (CIN) were measured in the ascorbic acid group (3.6% for all), NAC group (6.8%, 3.4%, 8.5%, respectively), combined group (5.5%, 5.5%, 9.1%, respectively), and control group (6.2%, 6.2%, 7.7%, respectively). None of these differences were significant (P = 0.896 for serum creatinine, P = 0.863 for creatinine clearance, and P = 0.684 for CIN).

Conclusions

In a cohort of patients at risk of developing CIN, we could not detect any significant benefit of the use of ascorbic acid, NAC, or a combination of both drugs over the standard hydration regimen in preventing CIN. (J Interven Cardiol 2013;26:90–96)

     

Racial Disparities in Left Main Stenting: Insights from a Real World Inner City Population

Background

Left main coronary artery (LMCA) disease is associated with significant cardiovascular mortality. The data on patient characteristics' predicting outcomes after LMCA revascularization is sparse.

Methods

A retrospective study of 227 patients with LMCA disease documented on coronary angiography from March 2000 to December 2008. Data included demographic variables, co‐morbidities, cardiac function, and medications. Race was self‐identified. The study outcome was a composite end‐point including myocardial infarction (MI) and all‐cause mortality. Cox proportional hazard analysis was performed to study the effect of various patient attributes including race and gender on the composite end‐point.

Results

Baseline characteristics were specifically compared between individuals who had the study outcome versus those who did not. Mean age was higher in the group with study outcomes when compared to the group without any outcomes (64.3 ± 11.8 years versus 59.2 ± 13.6 years; p = 0.013). After the final multivariate regression analysis, only African American (AA) race and age were found to be independent predictors of adverse cardiac outcome at the end of the first year (race—hazard ratio (HR) 3.82, 95% confidence interval (CI) 1.38–10.62, p = 0.010; age—HR 1.08, 95% CI 1.04–1.13, p < 0.001) and at the end of the study (race—HR 2.71, 95% CI 1.44–5.10, p = 0.002; age—HR 1.03, 95% CI 1.01–1.08, p = 0.017).

Conclusion

In our study of patients with unprotected LMCA disease, AA race, and age were significantly predictive of poor prognosis following revascularization, while gender had no predictive value in prognosticating cardiovascular mortality.

     

A Twin Study of Metabolic Syndrome and Autonomic Tone

Introduction: One possible mechanism of higher cardiovascular mortality associated with the metabolic syndrome (MetS) may be through abnormal modulation in autonomic tone.
Methods and Results: We examined the association between the MetS and autonomic tone as measured by heart rate variability (HRV) among 288 twins from the Twins Heart Study (THS). Of the 288 participants, 151 (52%) had the MetS. The MetS was associated with decreased HRV across all frequency ranges, and each additional MetS risk factor was associated with lower HRV. After adjustment for several potential confounders, very-low frequency (P < 0.001), low frequency (P < 0.001), and total power (P = 0.02) spectra of HRV remained significantly lower in twins with a progressively higher number of MetS components (18–50% decrease comparing twins with 5 risk factors to those with no risk factors). Among 87 twin pairs who were discordant for the number of MetS components, a one-unit increment in MetS components was associated with an 8% smaller very-low frequency (p = 0.03) and a 15% smaller low frequency spectrum (P = 0.002) comparing each twin with his brother.
Conclusion: MetS was associated with lower HRV in a well-characterized sample of middle-aged male twins. This association persisted even after controlling for genetic and shared environmental factors accounted for by comparison within twin pairs. Abnormalities of autonomic tone, as evidenced by lower HRV, may be partly responsible for the higher rate of atrial fibrillation, coronary heart disease, cardiac death, and overall mortality seen in patients with the MetS.     

The mode of anti‐arthritic peptide delivery impacts on the severity and outcome of adjuvant induced arthritis

Aim: A synthetic nonapeptide (core peptide [CP]) was tested as a potential therapeutic agent for the treatment of acute onset arthritis. Differing modes of delivery (subcutaneous [SCI]vs. intraperitoneal [IP]) and lipid conjugation of CP were examined. Methods: Wistar rats aged 9–12 weeks were injected SCI in the tail with 1 mg of heat‐killed Mycobacterium tuberculosis (MTB) to bring about adjuvant induced arthritis. After development of arthritis (day 12), 6 mg of CP, 6 mg of CP‐lipid conjugate (LP), or 1.2 mg cyclosporin A (Csp; 3 mg/kg) in 100 µL of diluent were given SCI or IP for 4 consecutive days. Severity of arthritis was assessed by changes in body weight, paw thickness, paw and ankle width, and the total number of arthritic joints involved up to 7 days after the first onset of arthritis and the commencement of treatment. Results: Core peptide and LP given either SCI or IP were effective in the treatment of acute adjuvant induced arthritis. IP administration of LP was significantly better than that of control and CP‐treated rats (P < 0.05) when examined at two separate time points, day 4 and day 7, after commencement of treatment. The effectiveness of IP‐administered LP was comparable to cyclosporin. Conclusions: CP‐lipid conjugate and CP have a therapeutic benefit in the treatment of acute arthritis. The mode of delivery and lipid conjugation of CP influences the efficacy and outcome of arthritis.     

Evaluation of a transgenic mouse model for alpha-1-antitrypsin (AAT) related liver disease

We have attempted to produce a transgenic mouse model of the neonatal liver disease associated with the human PIZ allele. Analysis of a number of transgenic mouse lines carrying either a normal human PIM gene construct or the mutant Z is reported. Using isoelectric focusing analysis of plasma from transgenic mice, we have shown that the human AAT proteins produced in mice are processed in a similar way to their counterparts in humans. By comparing the level of M and Z mRNA in liver with the levels of M and Z proteins in plasma we have inferred that, as in humans, the mutant protein tends to accumulate within the hepatocyte. Accumulation of Z protein has also been demonstrated by immunocytochemistry. Two of the M transgenic lines produce such high levels of the human protein that it, like the Z protein, accumulates as globules. Histological features of livers from 116 mice of different ages and genotypes were examined: 37 non-transgenic, 62 Z transgenic (23 low expressing and 39 high expressing) and 17 M transgenic mice, all high expressing. Cirrhosis or fibrosis was not seen in any animal and we were unable to find any evidence for neonatal liver disease. Some necrosis was seen in all genotypes and this increased significantly with age with one Z line showing significantly more frequent necrosis than any other group. This line, the highest expressing Z line, was back crossed onto 7 different genetic backgrounds but no major differences between the back crosses with respect to liver disease were observed. The mouse model we have developed is compared with other transgenic Z mouse models; none of these is representative of human neonatal liver disease. Our view is that the transgenic animals generated in these experiments may be most useful for investigating the liver manifestations that almost invariably occur in ZZ adults. Alteration of additional factors other than accumulation of Z protein, for example inactivation of the endogenous mouse genes or some environmental challenge, might produce a mouse model with more relevance to neonatal liver disease.     

HUMAN LEARNING DURING GENERAL ANAESTHESIA AND SURGERY

To determine if learning occurs during general anaesthesia,72 women undergoing surgery were given postoperative implicitmemory tests in which performance could be influenced by auditoryinformation presented during general anaesthesia. Two methodsof anaesthesia were used: nitrous oxide and opioids (n = 24)or nitrous oxide and isoflurane (1, 1.3 and 1.5 MAC for n =12, 24 and 12, respectively). Three tests showed some retention,apparently unconscious, of information presented during anaesthesia:in Behavioural Suggestions tests, patients who were instructedduring anaesthesia to touch a particular body part (ear or nose)during later questioning touched the "correct" (suggested) bodypart longer than the "incorrect" (not suggested) body part duringa postoperative interview on the day of surgery (means 2.5 vs0.2 s); in Word Completion tests, patients shown a page containingthe first three letters of words and asked to give words beginningwith those letters gave more words from a list that had beenplayed during anaesthesia than from a list not played (means0.48 vs 0.27 words); in Nonsense Word tests, patients who wereplayed different nonsense words between two and 16 times duringanaesthesia preferred and guessed more accurately those thathad been played most often (16 times) relative to those playedless often in subsequent preference and recognition tests (means56% vs 46% for preference and 62% vs 48% for recognition), whileshowing no such patterns in additional control tests. Learningdid not vary with the method of anaesthesia, as might have beenexpected if learning was a monotonic function of brain depression.Some information processing functions of the brain evidentlycontinue to function during adequate general anaesthesia. Presented in part at the First International Symposium on Memoryand Awareness in Anaesthesia, University of Glasgow, Glasgow,Scotland, April 6–9, 1989 and the American Society ofAnesthesiologists annual meeting, New Orleans, Louisiana, October14–18, 1989.     

Preliminary Clinical Results of a Biphasic Waveform and an RV Lead System

Biphasic defibrillation waveforms have provided a reduction in defibrillation thresholds in transvenous ICD systems. Although a variety of biphasic waveforms have been tested, the optimal pulse durations and tilts have yet to be identified. A multicenter clinical study was conducted to evaluate the performance of a new ICD biphasic waveform and new RV active fixation steroid eluting lead system. Fifty-three patients were entered into the study. Mean age was 63 years with a mean ejection fraction of 36.8%. Primary indication for implantation was monomorphic ventricular tachycardia alone (54.7%). Forty-eight patients (90.6%) were implanted with an RV shocking lead and active can alone as the anodal contact. The ICD can was the cathode. In four cases (7.5%), an additional SVC or CS had was used due to a high DFT with the RV lead alone. In an additional case, a chronic SVC lead was used although the RV-Can DFT was acceptable. DFT for all cases at implant was 9.8 ± 3.7 J. Repeat testing at 3 months for a subset of patients showed a reduction in DFT (7.4 ± 3.0 J), P value = 0.03. Sensing and pacing characteristics of the RV lead system remained excellent during the study period (acute 0.047 ± 0.005 ms at 5.4 V and 9.9 ± 6.2 mV R wave; chronic 0.067 ± 0.11 ms at 5.4 V and 9.3 ± 5.4 mV R wave). It is concluded that this lead system provides good acute and chronic sensing and pacing characteristics with good DFT values in combination with this waveform.