Evaluation of the tibial tunnel after intraoperatively administered platelet‐rich plasma gel during anterior cruciate ligament reconstruction using diffusion weighted and dynamic contrast‐enhanced MRI

Purpose:

To evaluate effect of platelet‐rich plasma gel (PRPG), locally administered during the anterior cruciate ligament (ACL) reconstruction, with two MRI methods. The proximal tibial tunnel was assessed with diffusion weighted imaging (DWI) and with dynamic contrast‐enhanced imaging (DCE‐MRI).

Materials and Methods:

In 50 patients, standard arthroscopic ACL reconstructions were performed. The patients in the PRPG group (n = 25) received a local application of PRPG. The proximal tibial tunnel was examined by DWI and DCE‐MRI, which were used to calculate apparent diffusion coefficient (ADC) values, as well as the contrast enhancement gradient (G_enh) and enhancement factor (F_enh) values.

Results:

At 1 month, the calculated average ADC value in the PRPG group was significantly lower than in the control group. At 2.5 and at 6 months, G_enh was significantly higher in the PRPG group. There were no significant differences in F_enh between the groups at any control examination.

Conclusion:

DWI and DCE‐MRI measurements indicate a reduced extent of edema during the first postoperative month as well as an increased vascular density and microvessel permeability in the proximal tibial tunnel at 1 and 2.5 postoperative months as the effect of the application of PRPG. J. Magn. Reson. Imaging 2013;37:928–935. © 2012 Wiley Periodicals, Inc.     

Electrical probing of cortical excitability in patients with epilepsy

Standard methods for seizure prediction involve passive monitoring of intracranial electroencephalography (iEEG) in order to track the 'state' of the brain. This paper introduces a new method for measuring cortical excitability using an electrical probing stimulus. Electrical probing enables feature extraction in a more robust and controlled manner compared to passively tracking features of iEEG signals. The probing stimuli consist of 100 bi-phasic pulses, delivered every 10 min. Features representing neural excitability are estimated from the iEEG responses to the stimuli. These features include the amplitude of the electrically evoked potential, the mean phase variance (univariate), and the phase-locking value (bivariate). In one patient, it is shown how the features vary over time in relation to the sleep-wake cycle and an epileptic seizure. For a second patient, it is demonstrated how the features vary with the rate of interictal discharges. In addition, the spatial pattern of increases and decreases in phase synchrony is explored when comparing periods of low and high interictal discharge rates, or sleep and awake states. The results demonstrate a proof-of-principle for the method to be applied in a seizure anticipation framework. This article is part of a Supplemental Special Issue entitled The Future of Automated Seizure Detection and Prediction.     

Heme oxygenase-1 induction by the clinically used anesthetic isoflurane protects rat livers from ischemia/reperfusion injury

OBJECTIVE: It was the aim of this study to characterize the influence of isoflurane-induced heme oxygenase-1 (HO-1) expression on hepatocellular integrity after ischemia and reperfusion. SUMMARY BACKGROUND DATA: Abundant experimental data characterize HO-1 as one of the most powerful inducible enzymes that contribute to the protection of the liver and other organs after harmful stimuli. Therapeutic strategies aimed at utilizing the protective effects of HO-1 are hampered by the fact that most pharmacological inducers of this enzyme perturb organ function by themselves and are not available for use in patients because of their toxicity and undesirable or unknown side effects. METHODS: Rats were pretreated with isoflurane before induction of partial hepatic ischemia (1 hour) and reperfusion (1 hour). At the end of each experiment, blood and liver tissue were obtained for molecular biologic, histologic, and immunohistochemical analyses. RESULTS: Isoflurane pretreatment increased hepatic HO-1 mRNA, HO-1 protein, HO enzyme activity, and decreased plasma levels of AST, ALT, and alpha-GST. Histologic analysis of livers obtained from isoflurane-pretreated rats showed a reduction of necrotic areas, particularly in the perivenular region, the predominant site of isoflurane-induced HO-1 expression. In addition, sinusoidal congestion that could otherwise be observed after ischemia/reperfusion was inhibited by the anesthetic. Furthermore, isoflurane augmented hepatic microvascular blood flow and lowered the malondialdehyde content within the liver compared with control animals. Administration of tin protoporphyrin IX inhibited HO activity and abolished the isoflurane-induced protective effects. CONCLUSIONS: This study provides first evidence that pretreatment with the nontoxic and clinically approved anesthetic isoflurane induces hepatic HO-1 expression, and thereby protects rat livers from ischemia/reperfusion injury.     

Haemodialysis clearance of baclofen

Background Baclofen is a centrally acting gamma-aminobutyric acid agonist used for spasticity of spinal origin and mainly excreted unchanged by the kidneys. We report haemodialysis clearance and the haemodialysis removal rate constant of baclofen in a comatose patient with baclofen overdose due to acute renal failure. Case report A 60-year-old man with spastic tetraplegia on chronic baclofen therapy was admitted due to pneumonia and acute renal failure. The patient became comatose and, as a result of the baclofen dosage being left unchanged despite a deterioration leading to renal failure due to hypotension, the concentration of baclofen was determined to be in the toxic range (0.70 mg/L). During a 4-hour-long bicarbonate haemodialysis the patient woke up and became completely orientated and cooperative. Baclofen therapy was subsequently stopped, and the patient remained conscious. The pharmacokinetics calculations revealed a baclofen haemodialysis removal rate constant of 0.152 h^-1 and a haemodialysis clearance of 2.14 mL/s. Conclusions Patients on a stable baclofen regime can develop baclofen toxicity due to acute renal failure. Haemodialysis removes baclofen as effectively as normal kidneys, and it would appear that haemodialysis is a reasonable treatment modality in patients with accidental baclofen overdose due to acute renal failure.     

Cardiac Toxicity of High-Dose Cyclophosphamide in Patients with Multiple Myeloma Undergoing Autologous Hematopoietic Stem Cell Transplantation

High-dose cyclophosphamide is a well-known mobilization regimen in patients with multiple myeloma undergoing autologous hematopoietic stem cell transplantation. Highly differing rates of cardiac complications associated with high-dose cyclophosphamide have been reported. To date, no systematic clinical study has investigated high-dose cyclophosphamide mobilization regimens in multiple myeloma patients and evaluated its cardiotoxicity. We administered high-dose cyclophosphamide (4 g/m2) to 23 consecutive multiple myeloma patients and followed the patients for 15 days by serially measuring the cardiotoxicity biomarkers troponin I (TnI), brain natriuretic peptide (BNP), and endothelin 1 (ET-1). Systolic and diastolic left ventricular function was assessed by complete echocardiography before and at 6 to 8 weeks after the therapy. Patients younger than 55 years showed significant differences between basal TnI levels and TnI concentrations determined at 15 days after high-dose cyclophosphamide treatment (P = .028). Significant differences between basal BNP concentrations and BNP levels measured at 8 hours after high-dose cyclophosphamide treatment were found in the entire group of patients as well as in 2 subgroups, patients younger than 55 years and those older than 55 years (P <.0001, P <.001, and P = .001, respectively). ET-1 results for the entire group of patients showed a significant difference between baseline ET-1 values and ET-1 values determined 8 hours after high-dose cyclophosphamide administration (P = .004). Echocardiographic measurements revealed a barely nonsignificant decrease in cardiac output after high-dose cyclophosphamide infusion compared with pretreatment values (P = .06), a result in accord with echocardiographically detected increases in mild functional mitral regurgitation (P = .025). TnI levels at 15 days after the completion of treatment correlated with left ventricular diastolic dysfunction, as indicated by the s/d index (r = 0.61; P = .04). In conclusion, the significant neurohumoral activation of heart failure occurring after high-dose cyclophosphamide treatment is manifested by an increase in BNP and ET-1 levels, yet without concomitant cardiomyocyte necrosis. BNP levels and to a lesser extent ET-1 levels are much more sensitive indicators of myocardial injury than functional tests, such as echocardiography, whereas diastolic functional parameters are more sensitive predictors of early cyclophosphamide-induced cardiotoxicity. Mild functional mitral regurgitation may develop in patients given high-dose cyclophosphamide therapy.     

Double venous drainage through the superior vena cava in minimally invasive aortic valve replacement: a retrospective study

Aim

To compare the outcomes of patients who underwent upper mini-sternotomy or right mini-thoracotomy and those who underwent full sternotomy and to report a technical improvement in venous drainage by means of double venous cannulation of the superior vena cava (SVC) in mini surgical procedures.

Methods

We retrospectively analyzed the outcome of 217 patients who underwent aortic valve replacement through upper mini-sternotomy or right mini-thoracotomy at the Department of Cardiovascular Surgery, University Medical Centre Ljubljana, Slovenia from 1996 till 2010. Cannulation of SVC and right atrial appendage was performed in 142/217 (65%) patients, while in the remaining 75 (35%) patients, double cannulation of SVC was used for venous drainage. The results of patients who underwent mini approaches were compared to 236 patients who underwent full sternotomy for the same purpose from 2009 to 2010 at the same center.

Results

We found a shorter mean length of intensive care unit stay, less volume chest-tube drainage, shorter crossclamp and cardio pulmonary bypass times, and less postoperative permanent pacemaker implantations in the minimally invasive group patients than in full sternotomy group patients. Using double cannulation of the SVC for venous drainage made venous cannulation in mini approaches easier and eliminated the need for obtaining femoral venous access.

Conclusion

Our study confirmed that even though technically challenging, upper mini-sternotomy and right mini-thoracotomy approaches for aortic valve replacement have potential advantages over conventional median sternotomy. They were proved to be safe, efficacious, and can significantly reduce surgical trauma and are therefore particularly valuable in some higher risk, obese, diabetic and elderly patients. Using double cannulation of SVC for venous drainage made venous cannulation easier and eliminated the need for obtaining femoral venous access.Minimally invasive cardiac valve surgery for patients with isolated valve pathology was introduced at the Department of Cardiovascular Surgery, University Medical Centre Ljubljana, Slovenia in 1996, the same year as at the Brigham and Women’s Hospital Boston, Loma Linda University, and the Cleveland Clinic (1,2). Less invasive approaches (upper mini-sternotomy, right mini-thoracotomy) confer many advantages when compared to median sternotomy, which is still considered a standard approach for the surgical repair or replacement of cardiac valves (3). It is true that the latter offers excellent exposure of the operating field, however the less invasive approaches lead to a smaller surgical wound and potentially less blood loss, decreased risk of infection, shorter intubation period, decreased postoperative pain, earlier hospital discharge, and a smaller, cosmetically more acceptable post-operative scar (4,5). Moreover, when re-operation is needed after mini incisions, it is less hazardous because the pericardium has not been completely dissected (6). They, on the other hand, can be quite challenging for the surgeon, sometimes making the standard venous cannulation of the superior vena cava (SVC) and right atrial appendage impossible due to insufficient exposure of the right atrial appendage and therefore constraining the surgeon to other ways of venous drainage. One of such ways is the well known cannulation of the SVC and femoral vein, where patient is subjected to femoral venous access (7). In order to be as little invasive as possible and avoid the latter, we performed a double venous cannulation of the SVC, first in the patients in whom a standard venous drainage was not possible and then also as a primary means of venous drainage.The aim of this study was to present the outcome of 217 patients who underwent aortic valve replacement through upper mini-sternotomy or right mini-thoracotomy and compare it to our contemporary full sternotomy cohort and to report our new technical improvement in venous drainage by means of double venous cannulation of the SVC in mini surgical procedures.     

Dual cerebral protection technique during carotid stenting.

PURPOSE: To present a technique for internal carotid artery stenting (CAS) with dual cerebral protection in patients with high-grade stenosis caused by large, soft atherosclerotic plaques. TECHNIQUE: The MO.MA proximal cerebral protection device is first placed in the external and common carotid arteries. Complete blockade of blood flow is achieved by inflating the occlusion balloons. A Spider filter is delivered to the distal internal carotid artery. All procedural steps of CAS are performed during continuous and simultaneous proximal occlusion and distal filter protection. After postdilation of the stent, the occlusion balloons are deflated, and antegrade flow is re-established with the distal filter basket still open. CONCLUSION: In selected patients with large atherosclerotic plaques, a dual cerebral protection technique during CAS may be a more efficacious form of cerebral protection than a single protection device.