Methylation status in females with rett syndrome

The authors studied methionine and creatine metabolism in females with Rett syndrome. Plasma metabolites (including methionine, homocysteine, guanidinoacetate) and urine creatine/creatinine ratios in 29 females with Rett syndrome were within the age-appropriate range. Although the authors have not been able to identify any abnormalities, it can be speculated that patients with Rett syndrome may benefit from dietary intervention to increase the supply of labile methyl groups to affected tissues.

Does totally endoscopic access for off-pump cardiac surgery influence the incidence of postoperative atrial fibrillation in coronary artery bypass grafting? A preliminary report

BACKGROUND

The occurrence rate of atrial fibrillation (AF) after coronary artery bypass grafting, quoted in the literature, is wide ranging from 5% to over 40%. It is speculated that, off-pump coronary artery bypass grafting (OPCAB) and also minimally invasive cardiac surgery reduces the incidence of postoperative AF due to reduced trauma, ischemia, and inflammation. Current data, however, do not clearly answer the question, whether the incidence of postoperative AF is reduced in using minimally invasive techniques, ideally resulting in the combination of both small access and off-pump surgery. The aim of this study was to evaluate the incidence of postoperative AF in patients undergoing totally endoscopic off-pump coronary artery bypass grafting (TECAB).

METHODS

A retrospective analysis of 72 patients undergoing myocardial revascularization was performed. Early postoperative incidence of AF was compared between three groups of patients: 24 after conventional coronary artery bypass grafting (CABG), 24 after OPCAB, and 24 after totally endoscopic off-pump CABG. Clinical profile of the patients, including factors having potential influence on postoperative AF was matched for groups.

RESULTS

Postoperative AF occurred in 25% of the patients in the CABG group, in 16% of the patients in the OPCAB group, and in 16% of the patients in the TECAB group. This difference has no statistical significance. Risk factors and incidence of postoperative complications were comparable in all groups excepting the number of distal anastomoses. There was a statistical significance between CABG group and TECAB group.

CONCLUSION

Avoiding cardiopulmonary bypass and minimizing surgical trauma did not reduce the incidence of postoperative AF in this patient collective. It remains an attractive hypothesis that postoperative AF is reduced by off-pump myocardial revascularisation and minimizing surgical trauma but more robust data are required.

Low-dose remifentanil to suppress haemodynamic responses to noxious stimuli in cardiac surgery: a dose-finding study

BACKGROUND

High-dose remifentanil (1-5 microg kg-1 min-1), commonly used for cardiac surgery, has been associated with muscle rigidity, hypotension, bradycardia, and reduced cardiac output. The aim of this study was to determine an optimal lower remifentanil dose, which should be accompanied by fewer adverse events, that still effectively suppresses haemodynamic responses to typical stressful stimuli (i.e. intubation, skin incision, and sternotomy).

METHODS

Total i.v. anaesthesia consisted of a target-controlled propofol (2 microg ml-1) and a remifentanil infusion. Forty patients were allocated to receive either a constant infusion of remifentanil at 0.1 microg kg-1 min-1 or up-titrations to 0.2, 0.3, or 0.4 microg kg-1 min-1, respectively, 5 min before each stimulus. Subsequently, changes in heart rate and mean arterial blood pressure were recorded for 8 min. Increases exceeding 20% of baseline were considered to be of clinical relevance. Patients who exhibited these alterations were termed responders.

RESULTS

The number of responders was less with the two higher remifentanil dosages (P<0.05) while propofol target doses could either be kept at the same level or even be reduced without affecting the plane of anaesthesia. Although single phenylephrine bolus had to be applied more frequently in these two groups (P<0.05), no severe haemodynamic depression was observed.

CONCLUSIONS

Remifentanil at 0.3 and 0.4 microg kg-1 min-1 in combination with a target-controlled propofol infusion in the pre-bypass period is well tolerated. It appears to mitigate potentially hazardous haemodynamic responses from stressful stimuli equally well as higher doses when compared with data from the literature.

Primary pigmented nodular adrenocortical disease (PPNAD) and pituitary adenoma in a boy with sporadic Carney complex due to a novel, de novo paternal PRKAR1A mutation (R96X)

We report the sporadic case of a 9 year-old boy with Carney syndrome, who presented with precocious puberty due to the endocrinological effects of primary pigmented nodular adrenocortical disease (PPNAD) and a synchronous pituitary adenoma. The adrenal tumor was removed surgically. Following unsuccessful treatment with bromocriptine the pituitary adenoma was also resected and a residual tumor irradiated. Thirty months after diagnosis the boy is free of symptoms. Mutation screening of the entire coding region of the PRKAR1A gene identified five single nucleotide exchanges, four of which were either heterozygous or homozygous polymorphic variants that were also present in his parents. However, the hitherto unreported disease-relevant mutation R96X in exon 3 had occurred de novo on the paternal allele.

Behavior of gaseous microemboli in extracorporeal circuits: air versus CO2

BACKGROUND

Open heart surgery is associated with serious risk of cerebral and peripheral organ dysfunction, attributed in part to air microbubbles generated in or not eliminated from the extracorporeal circuit (ECC). Venous air leakage leads to increased arterial bubble load. CO2 replacing air in cardiac chambers show faster resorption times, reducing possible cerebral or peripheral organ damage after heart valve interventions. In two models of ECC the effect of air entering closed circuits was demonstrated and compared to the effect of CO2 entry.

METHODS

Fragmentation and dissolution of gas (0.5 mL) was evaluated in an in vitro model of ECC, using ultrasonic bubble detection. Air leakage (10 mL) in the venous line of the ECC was simulated and compared to the effect of the same quantity of CO2 entering the circuit. Both models used whole blood priming and physiological conditions, verified with blood gas analyses.

RESULTS

Fragmentation and dissolution of gas bubbles injected into a closed ECC could be demonstrated, complete resorption of CO2 bubbles was observed earlier than complete resorption of room air (5.0+/-0.6 vs. 14.4+/-5.9 min, p=0.0009). CO2 entering the venous line lead to 40% less arterial bubble load as compared to the same amount of room air entering the circuit (2099+/-991 vs. 3555+/-632, p=0.005).

CONCLUSIONS

Current ECC systems fail to eliminate gas entering the circuit, leading rather to microbubble dispersion. CO2 is much faster resorbed within the circuit than room air. In open heart surgery as valvular operations, CO2 insufflation into the operative field is protective, as we have demonstrated in our models.

Approaching actinide(+III) hydration from first principles

A systematic computational approach to An(III) hydration on a density-functional level of theory, using quasi-relativistic 5f-in-core pseudopotentials and valence-only basis sets for the An(III) subsystems, is presented. Molecular structures, binding energies, hydration energies, and Gibbs free energies of hydration have been calculated for [An(III)(OH(2))(h)](3+) (h = 7, 8, 9) and [An(III)(OH(2))(h-1) * OH(2)](3+) (h = 8, 9), using large (7s6p5d2f1g)/[6s5p4d2f1g] An(III) and cc-pVQZ O and H basis sets within the COSMO implicit solvation model. An(III) preferred primary hydration numbers are found to be 8 for all An(III) at the gradient-corrected density-functional level of theory. Second-order Møller-Plesset perturbation theory predicts preferred primary hydration numbers of 9 and 8 for Ac(III)-Md(III) and No(III)-Lr(III), respectively.

Eignung des portablen Blutgasanalysegeräts OPTI® CCA zur Untersuchung arterieller Blutproben des Pferdes

Gegenstand und Ziel: Ziel der Untersuchung war, die Eignung des tragbaren Blutgasanalysegeräts Roche OPTI® CCA zum Einsatz in der Bestimmung arterieller Partialdrücke beim Pferd zu überprüfen. Material und Methoden: Arterielle Blutproben von 25 Pferden wurden vergleichend mit dem OPTI® CCA und dem OMNI® untersucht. Die Auswertung umfasste folgende Parameter: arterielle Partialdrücke von Sauerstoff (paO2) und Kohlendioxid (paCO2); pH-Wert (diese drei Parameter auch temperaturkorrigiert); alveoloarterielle Sauerstoffpartialdruckdifferenz (p(A-a)O2); Basenabweichung in vitro (BE); aktuelles Bikarbonat (HCO3 –) sowie Barometerdruck. Ergebnisse: Mithilfe des Mittelwertvergleichs (t-Test) ließen sich keine statistisch signifikanten Unterschiede der Partialdrücke nachweisen. Beide Geräte korrelierten bezüglich des Barometerdrucks hochsignifikant (r = 0,99), wenngleich die absoluten Werte am OPTI® CCA durchschnittlich hochsignifikant niedriger lagen. Für die Säure-Basen-Parameter (pH-Wert, BE, HCO3 –) wurden am OPTI® CCA im Mittel hochsignifikant höhere Werte bestimmt, wobei die Ergebnisse für den pH-Wert (bei 37 °C und temperaturkorrigiert) nur eine mäßige Korrelation zeigten (r = 0,68 bzw. r = 0,79). Die Bland-Altman-Analyse ergab für alle Parameter mit Ausnahme des BE keine Abhängigkeit der Messwertdifferenzen von der Wertehöhe. Schlussfolgerung und klinische Relevanz: Die statistisch nachgewiesenen Unterschiede zwischen den Geräten liegen (mit Ausnahme des BE) im klinisch nicht relevanten Bereich. Somit eignet sich der OPTI® CCA zur Bestimmung arterieller Blutgaswerte (Partialdrücke) und der Ermittlung des Säure- Basen-Status beim Pferd ebenso gut wie der OMNI®.

Decalcification of the Mitral Annulus: Surgical Experience in 81 Patients

OBJECTIVE

Mitral valve surgery in the presence of extensive calcification of the mitral annulus is a technical challenge and increases perioperative risk. This study reviews our experience with decalcification of the mitral annulus in patients undergoing mitral valve reconstruction or replacement.

METHODS

From 1995 to 2003, 81 patients (mean age 64 +/- 13 years, 30 male, 51 female) with extensive calcification of the mitral annulus underwent mitral valve repair (n = 42) or replacement (biological n = 20, mechanical n = 19). The mean follow-up was 24 months. Patients presented with a mean EuroSCORE of 7. Concomitant surgical procedures were performed in 62 %. Patient outcomes were retrospectively assessed.

RESULTS

Perioperative survival was 97.5 % (n = 79) and hospital survival was 91.3 % (n = 74). Two-year survival was 88.9 %. Eight patients needed reexploration due to bleeding and five patients required prolonged mechanical ventilation. No perioperative stroke was observed. Freedom from reoperation was 90.2 % (n = 73). Early reoperation for recurrent incompetence was necessary in 3 patients and late reoperation in 5 patients.

CONCLUSIONS

Despite the elevated perioperative risk and the high risk of reoperation with this procedure, decalcification of the annulus and repair/replacement of the mitral valve could be performed with good clinical results.

Aprotinin in der Kardiochirurgie

Antifibrinolytic therapy with the serine protease inhibitor Aprotinin or the lysine analogues epsilon-aminocapronic acid or tranexamic acid is a therapeutic measure to reduce perioperative blood loss during cardiac surgery. In an international, prospective, non-randomised phase 4 observation study, Mangano et al. investigated the effectiveness and side-effects of Aprotinin, epsilon-aminocapronic acid and tranexamic acid in comparison to no antifibrinolytic therapy in a total of 4,374 patients who underwent cardiac surgery with extracorporeal circulation. In the opinion of Mangano et al. the results of this study question the safety and effectiveness of Aprotinin for reduction of perioperative blood loss by cardiac surgery patients. Despite a critical review of the study and results reported by Mangano et al., the authors of the present paper come to the conclusion that, in view of the availability of more reasonably priced alternatives in Germany, it appears to be sensible to give preference to tranexamic acid instead of aprotinin.

Assessment of the distal anastomosis of coronary artery bypass grafts with a 2D T2-weighted turbo spin echo sequence and correlation to conventional coronary angiography

OBJECTIVE

The aim of the study was to evaluate the patency of the distal anastomoses of coronary artery bypass grafts and to detect graft stenoses and occlusions with a magnetic resonance (MR) spin echo sequence.

PATIENTS AND METHODS

One hundred and eighty-five patients with 481 distal anastomoses were examined with a 1.5 T MR scanner and coronary angiography. A 2-dimensional T2-weighted breath-hold half-Fourier acquisition single-shot turbo spin echo sequence (Haste) was performed. All images were evaluated independently by a radiologist and cardiologist and compared to the conventional coronary angiography. The observers were blinded to the coronary angiography findings, but informed in regard to the surgical graft anastomosis.

RESULTS

With the Haste sequence, 76% of the distal anastomoses were recognized (368/481). Forty-five of 52 (87%) stenoses and all occlusions were identified. The sensitivity and specificity for the evaluation of the distal anastomosis with the spin echo sequence was 87% and 96%. Twenty-four percent of the distal anastomoses were not identified due to a poor image quality or motion artefacts.

CONCLUSION

Using the Haste sequence, a reliable assessment of graft patency of the distal anastomosis is possible. Further improvements of the spatial resolution and the image quality are necessary to recommend this MR technique for routine clinical use.

Detection of vein graft disease using 4-row computed tomography. Evaluation of coronary bypass graft patency and correlation with the Ca-score

BACKGROUND

Multi-row computed tomography (MDCT) is a promising non-invasive technique and capable of rapid imaging of cardiac structures, including coronary arteries and bypass grafts during a single held breath. In this study, we evaluated coronary artery bypass graft (CABG) patency by comparing 4-slice computed tomography with conventional contrast angiography. One disadvantage of MDCT is the limited diagnostic accuracy with + increased calcification of the grafts. Therefore, the correlation between Ca-grading and diagnostic accuracy was examined.

METHODS

We examined 30 patients with 104 bypass grafts with a 4-row MDCT scanner. On the basis of the Ca-score, patients were divided into 3 groups.

RESULTS

It was possible to assess the exact degree of stenosis in 25 of 32 > 50% stenoses with 4-row MDCT, 7 stenoses were underestimated. All occlusions in 21 patients were identified correctly, 33 graft segments were underestimated in MDCT, of which 28 were in the group with a Ca-score of > 800.

CONCLUSIONS

MDCT allows non-invasive angiographic evaluation of coronary bypass grafts with a high diagnostic accuracy. However, the method strongly depends on the degree of vascular calcification and underrates the degree of stenosis subject to the Ca-score. This is a distinct limitation in distal vascular segments of small calibre which cannot be validly displayed. In patients with low or moderate Ca-score values, MDCT coronary angiography is promising new technique with a high diagnostic accuracy for the detection of graft stenosis or occlusions.