SUMMARY
Ventricular septal defects (VSDs) are one of the most common congenital cardiac malformations. They are generally classified into 4 groups depending upon their location in the interventricular septum: supracristal, perimembranous, inlet and muscular VSDs.
Perimembranous VSDs form about 80% of the defects. Surgical closure of pmVSD is a well-established therapy, but still carries many risks such as tricuspid incompetence, complete heart block, early &late arrhythmias and postpericardiotomy syndrome. Complications of cardiopulmonary bypass, blood priming, bad thoracotomy scar & wound infection are also documented.
That is why an alternative trans catheter approach for closure of pmVSD has been attempted with various types of occluding devices: Asymmetric Amplatzer VSD occluder, Amplatzer Muscular VSD occluder and Amplatzer Duct Occluders I &II. However, catheter closure is not appropriate in certain conditions such as severe aortic valve prolapse, large VSD with pulmonary hypertension and small infants with low body weight, and such cases should be referred for open heart surgery.
Conduction disturbances are common complications after pmVSD closure, due to the close proximity of the defect to the conduction system. These include complete heart block, whether temporary or permanent requiring pacemaker and other minor ECG abnormalities like RBBB and LBBB.
Conventional Echocardiography is the mainstay for assessing the size of the defect, chamber dimensions, ventricular function and effect on mitral, aortic or tricuspid valves. Tissue Doppler Imaging (TDI) is a new technique that uses Doppler signals to quantify regional myocardial velocities in septum, anterior or posterior walls.
This study is a cross-sectional study done on 80 patients with pmVSDs following surgical or transcatheter defect closure within a period of 6 months up to 2 years following the VSD closure. 20 normal age-matched healthy children were included as control group.
Children who had surgical VSD closure had significantly younger age and lower body surface area than those closed via transcatheter approach. Preoperative Echo showed that patients in the surgical group had significantly larger VSD and lower transventricular pressure gradient than the catheter group. Consequently, subjects whose VSDs were closed surgically had higher values for left atrial &left ventricular dimensions, tricuspid regurge and estimated systolic pulmonary pressure. However, there was no significant difference in preoperative global systolic and diastolic functions between the 2 groups.
Following VSD closure, the period of ICU stay and postoperative morbidity were significantly increased in the surgical group. Main complications encountered after surgical closure in this study were wound infection, pneumonia, infective endocarditis, postpericardiotomy syndrome and major arrhythmias. Meanwhile, post device closure, the majority of complications were vascular and minor rhythm changes.
This study showed significant reduction in LVEDD, LAD and RVD z-scores in patients after VSD closure in both groups. Values of estimated systolic pulmonary artery pressure decreased significantly after closure of VSD, but postoperative values were still higher in surgical group.
The results of the current study showed that the decrease in systolic function was more in surgical patients; however, there was no significant difference in diastolic function between the 2 groups as detected by conventional echocardiography.
Meanwhile, in comparison with the healthy controls, there was a significant difference in postoperative values for ejection fraction during midterm follow up in both groups than normal subjects.
Tissue Doppler Imaging offers many potential advantages in quantifying subtle impairment of ventricular performance. The results of this study showed that TDI values for assessment of systolic and diastolic functions were significantly more impaired post-surgical closure, with the effect more detrimental on septal mechanics.
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