Prophylactic effect of angiotensin receptor blockers in children with genetic aortopathies: the early bird catches the worm

AIMS

In genetic aortopathies (GA) particular attention is paid to aortic root dilatation which has an impact on morbidity and mortality. This study focuses on the effects of therapy with angiotensin-II-receptor-blockers (ARB) or beta-blockers (BB) on aortic root growth and the question which therapy should be initiated at which dosage and at what age.

METHODS

Since 1998 we diagnosed 208 patients with GA (170 FBN-1). 81 patients between 5 months and 18 years receiving either ARB or BB therapy were included. We retrospectively analyzed the progression of the dilatation of Sinus Valsalva aortae (SV) using calculated z-scores before and after therapy initiation and compared BB and ARB treatment.

RESULTS

Both ARB and BB (p < 0.05) therapy showed significant improvement in aortic root growth, while the effect is significantly more pronounced in ARB (p < 0.01) independent of age and genetic cause. A detailed comparison of the two drug groups showed a more sustained effect in limiting the progression of the dilatation of the aortic root in patients treated with ARB. Progression of dilatation of the SV was significantly lower in children treated with ARBs compared to BB (delta z-score, p < 0.05). In addition, ARBs were better tolerated and had a significantly lower discontinuation rate (3%) compared to BB (50%) (p < 0.01). Independently of age at initiation all children and adolescents were able to reach the target dose under ARB.

CONCLUSION

We demonstrated a significant change in both treatment options, with the effect of ARB being more pronounced while being better tolerated throughout the treatment period.

[Improvements in implantable mechanical circulatory support systems : literature overview and update]

In recent years, ventricular assist devices (VAD) supporting the left (LVAD), the right (RVAD) or both ventricles (BVAD) have rapidly emerged as the standard of care for advanced heart failure patients. Both the numbers and ages of patients in which they are used are rising worldwide, especially when used as a permanent support (bridge to destination, BTD). Due to the continuing lack of donor organs, these devices now represent a viable alternative to bridge patients to transplantation (BTT), with a 1-year survival rate of 86%. BTD, especially in long-term support, might be a valid, and the sole, option for those patients in whom heart transplantation is contraindicated. Patient selection, pre- and intra-operative preparation, as well as the timing of VAD implantation are important factors critical to successful circulatory support. While BTT remains the goal in the majority of patients, the number of permanent VADs (i. e. BTD) is rising significantly. Although explantation of a VAD system as a bridge to recovery (BTR) can be considered in only a small number of patients, it represents a very special part of this therapy modality.

Onset of pulmonary stenosis after arterial switch operation for transposition of great arteries with intact ventricular septum

INTRODUCTION

Pulmonary stenosis remains the most frequent complication and cause of reintervention after the arterial switch operation for transposition of the great arteries We investigated the onset, incidence, and outcome of pulmonary stenosis after arterial switch operation in neonates with transposition of the great arteries and intact ventricular septum.

METHODS

Arterial switch operation using Lecompte maneuver was performed in 222 neonates with transposition of great arteries and intact ventricular septum. Complete medical records with serial echocardiograms were available for 174 (73%) patients and were reviewed for incidence of postoperative pulmonary stenosis defined as a thickened and doming pulmonary valve and/or a pressure gradient of >25 mmHg.

RESULTS

During a mean follow-up of 14.4 ± 0.54 years, 31 children developed pulmonary stenosis. Onset of significant stenosis occurred as early as 30 days and as late as 10 years after arterial switch operation. Uncomplicated interventional balloon/stent angioplasty was performed in 11 patients with supravalvular stenosis (mean pressure gradients of 65 mmHg). Severe restenosis occurred in these patients post-angioplasty (range 2-7 years). In other 10 patientseither patch enlargement of the area involved or angioplasty were performed. Freedom from intervention was 68.6±8.7% at 1 year and 42.8.1±9.5% at 15 years and onwards.

CONCLUSION

Over time, pulmonary stenosis developed after arterial switch operation. Balloon angioplasty for supravalvular pulmonary stenosis could be the initial treatment of choice owing to the high success rate. Surgical intervention is offered to those with pulmonary valve stenosis having pressure gradients of >50 mmHg, and for re-stenosis after intervention/stent implantation.

Dynamic changes in cerebral oxygenation related to deep hypothermia and circulatory arrest evaluated by near-infrared spectroscopy

BACKGROUND

Total circulatory arrest in deep hypothermia, which is used in corrective surgery of complex cardiovascular malformations, has been said to cause brain injury. Near-infrared spectroscopy (NIRS) is a new non-invasive method that potentially monitors changes in cerebral oxygenation and tissue oxygen utilisation. The aim of this experimental study in rabbits was to evaluate the change in intravascular and intracellular oxygenation patterns during cooling, deep hypothermic circulatory arrest and rewarming using a commercially available NIRS-cerebral oximeter.

METHODS

Ten New Zealand White male rabbits (weight, 3.1+/-0.25 kg BW) were included in this study. All animals underwent cardiopulmonary bypass (CPB), cooling to a rectal temperature below 15 degrees C, 60 min of deep hypothermic circulatory arrest (DHCA) followed by reperfusion and rewarming. Cerebral oxyhaemoglobin (HbO2), deoxyhaemoglobin (HHb) and cytochrome oxidase aa3 (CytOxaa3) concentrations were continuously measured during the entire procedure using the Cerebral RedOx Monitor 2020 (Criticon cerebral redox monitor 2020, Johnson & Johnson Medical). Total haemoglobin concentration (tHb) and regional cerebral oxygen saturation (rSO2) values were calculated by integrated algorithm.

RESULTS

In all animals an initial increase of oxygenated haemoglobin (HbO2, rSO2) and a fall in deoxygenated haemoglobin (HHb) were found during cooling on bypass. A slight decrease in CytOxaa3 signal was observed in response to initial cooling. Variation in intravascular haemoglobin oxygenation parameters (HbO2, HHb) were related to haemodynamic changes associated with fluid loading, initiation and termination of CPB, bypass flow rate and cooling and rewarming. When the pump flow was stopped all NIRS parameters, except the HHb value, decreased precipitously during the DHCA-period (P<0.01). After reperfusion and rewarming, all haemoglobin oxygen saturation readings returned nearly to pre-CPB levels (P=0.09), but the CytOxaa3 was still significantly lower than the pre-CPB levels (P<0.05).

CONCLUSION

The change in the NIRS-derived haemoglobin oxygenation parameters may reflect physiological changes in systemic and cerebral haemodynamics. CytOxaa3 values may represent related effects on cellular oxygenation. Thus, continuous, real-time NIRS-monitoring may identify critical periods with inadequate brain tissue oxygenation, particularly during DHCA. The neurological implications of the observed changes in NIRS oxygenation parameters, however, require further quantitative morphological evaluation of the brain in animals surviving a longer reperfusion and observation period.