A measured approach to managing the aortic root in patients with bicuspid aortic valve disease

Bicuspid (or bicommissural) aortic valve (BAV) is the most common cardiovascular malformation in humans, with a prevalence of 1% to 2% in the general population and a 2:1 male:female ratio. BAV is frequently associated with other cardiovascular malformations, including aortic root dilatation, which affects about 40% of individuals with BAVs and is thought to be associated with increased risk of dissection and/or rupture. Currently, no agreement exists about the optimal management of these patients. We review the pathophysiology and possible determinants of aortic disease associated with BAV, the natural history of aortic wall size progression, and suggest management strategies to prevent acute aortic events.     

Pathophysiologic significance of left ventricular hypertrophy in dilated cardiomyopathy

Background and hypothesis: Patients with dilated cardiomyopathy (DCM) with left ventricular hypertrophy (LVH) have been found to have a better prognosis than patients without LVH. However, the pathophysiologic mechanism for that has not been investigated. We sought to clarify the pathophysiologic significance of LVH in DCM. Methods: We performed isoproterenol infusion echocar-diography (0.02 m?g/kg/min) in 17 patients with DCM, and measured plasma epinephrine and norepinephrine levels at rest and at the end of ergometer exercise in 14 of the 17 patients. Patients were classified into groups according to the presence (9 patients) (LVH+) or absence (8 patients) (LVH-) of LVH. Left ventricular hypertrophy was defined as an inter-ventricular thickness or posterior wall thickness ≥13 mm. Results: Although there was no significant difference between groups in fractional shortening at rest during isoproterenol infusion, fractional shortening was significantly higher in the LVH (+) group than in the LVH (-) group (29 ± 9 vs. 17 ± 8%;p<0.025). Although there was no significant difference in plasma norepinephrine level, it was significantly lower in the LVH (+) group than in the LVH (-) group (233 ± 169 vs. 519 ± 258 pg/ml;p<0.05) at the end point of the exercise. Conclusion: Systolic reserve, represented by the response to isoproterenol, is greater in patients with DCM with LVH than in those without LVH, and a lower plasma level of norepinephrine is needed to activate the myocardium during ex ercise in patients with DCM with LVH. This pathophysiologic characteristic could be one of the mechanisms which explain a better prognosis in patients with DCM with LVH.     

Intraoperative complications using the Bio-Transfix femoral fixation implant in anterior cruciate ligament reconstruction

The use of biodegradable Transfix femoral fixation technique is a safe and well-accepted method when performing anterior cruciate ligament reconstruction. We report on three cases of deformation and back out of the Bio-Transfix implant over the lateral, distal femoral cortex, with failure of the passing wire when advancing the graft into the femoral tunnel in one of these patients. Two of the patients presented with symptoms of iliotibial band friction syndrome, while the third patient was asymptomatic. The graft had clinically integrated demonstrating AP and rotational stability. The symptoms relieved after removal of the failed Bio-Transfix implants in the symptomatic patients. The aetiology of the implant failure and the alternative methods to avoid such complications are discussed.     

Rejection of persistent‐bounded disturbances in continuous time‐delay systems using observer‐based feedback

In this paper, the problem of persistent‐bounded disturbance rejection of linear continuous‐time systems with time‐varying delays is investigated using the tools of invariant set analysis and Lyapunov‐function methodology. We derive less conservative sufficient conditions on robust attractor for time‐delay systems in terms of strict linear matrix inequalities (LMIs) to guarantee the desired ??₁‐performance. A robust output‐feedback controller is designed and the associated gain is determined using strict LMIs. The developed results are tested on two representative time‐delay examples. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of conversion from mycophenolate mofetil to enteric-coated mycophenolate sodium on maximum tolerated dose and gastrointestinal symptoms following kidney transplantation

Despite the potential tolerability advantage of enteric-coated mycophenolate sodium (EC-MPS), no prospective, randomized trial has evaluated whether conversion from mycophenolate mofetil (MMF) to EC-MPS permits mycophenolic acid dose to be increased or gastrointestinal side-effects to be ameliorated. In a randomized, multicenter, open-label trial, kidney transplant recipients experiencing gastrointestinal side-effects either remained on MMF or switched to an equimolar dose of EC-MPS, adjusted 2 weeks subsequently to target the highest tolerated dose up to 1440 mg/day (EC-MPS) or 2000 mg/day (MMF). Patients were followed up to 12 weeks postrandomization. One hundred and thirty-four patients were randomized. The primary efficacy endpoint, the proportion of patients receiving a higher mycophenolic acid (MPA) dose at week 12 than at randomization, was significantly greater in the EC-MPS arm (32/68, 47.1%) than the MMF arm (10/61, 16.4%; P  < 0.001). At the final visit, 50.0% (34/68) of EC-MPS patients were receiving the maximum recommended dose versus 26.2% (16/61) of MMF patients ( P  = 0.007). Kidney transplant patients receiving reduced-dose MMF because of gastrointestinal side-effects can tolerate a significant increase in MPA dose after conversion to EC-MPS. Patient-reported gastrointestinal outcomes with higher doses of EC-MPS remained at least as good as in MMF-treated controls.     

Bridge to transplantation with a left ventricular assist device for systemic ventricular failure after Mustard procedure

In recent years the conservative techniques to treat degenerative mitral valve insufficiency have developed to such an extent mainly due to a better understanding of the physiology and pathology of the mitral valve and to the possibility to get predictable and satisfactory results. Still a challenge persists for the cardiac surgeon when he has to deal with complex reconstructions. The technique described seems to offer an even better surgical option for patients with complex lesions involving the posterior mitral leaflet, especially as far as the hemodynamic performance is concerned.