repair of inter-ventricular communication
Inter-ventricular communication (abbreviated CIV) is the most common congenital heart defect and represents nearly 40% of all congenital heart diseases in humans.
In the normal heart, the wall that separates the right and left ventricles, called the "interventricular septum", is totally hermetic. A CIV corresponds to the presence of a more or less wide orifice in this partition, allowing direct passage of blood from one ventricle to the other. The consequences of this malformation essentially depend on the size of the communication. In most cases, the orifice is small and these CIVs without really bothersome consequences are called "Roger's disease". The evolution of a VSD depends on its location on the septum, some being likely to close spontaneously in the months or years following birth.
The presence of an isolated CIV is usually of no consequence before birth. The fetal circulation is in fact already based on the presence of two communications between the right heart and the left heart, the oval foramen at the entrance to the heart, the arterial canal at its exit. Provided that there is no other malformation present, the existence of an additional communication, located between the two preceding ones, modifies only very little the circulation of the blood and this all the more so than in the fetus , the blood pressure is practically equal in the two ventricles. The amount of blood that passes through the VSD is therefore minimal, usually directed from the right ventricle to the left ventricle, especially in the third trimester of pregnancy.
Normally, the foramen ovale and the ductus arteriosus close and a pressure difference is gradually established between the right heart (right atrium, right ventricle and pulmonary arteries) and the left heart (left atrium, left ventricle and aorta). The pressure tends to drop sharply in the right heart, especially the right ventricle (where the pressure drops from about 60 mmHg to about 20–25 mmHg). It remains stable then increases in the left heart and in particular in the left ventricle where its evolution can be assessed simply by measuring blood pressure. The passage of blood through the VSD therefore tends to increase, its importance depending on the size of the orifice and the pressure difference on either side of the communication.
It is a treatment aimed at reducing the manifestations of heart failure and pulmonary oedema. It may be indicated in infants in the first months of life. It will possibly (but not always) be initiated during a short hospitalization, but the general rule is to avoid hospitalizations as much as possible (and even more prolonged hospitalizations), and to carry out this treatment at home, with drugs given by oral route, under cover of regular monitoring in consultation.
This treatment is based on the use of Digoxin (digitalic), the usefulness of which is disputed by some, diuretics (drugs increasing diuresis) and vasodilator drugs such as inhibitors of the enzyme of conversion of the mainly angiotensin. We will often add childcare measures such as rest and calm, temperate atmosphere in the room, elevated position of the head of the cradle, feeding with enriched milk, etc. and patience of parents when taking bottles which is desperately slow. We will limit contact with those around us as much as possible (in particular school-going brothers or sisters) to limit the risk of infectious contagion. For the same reasons, stays in a crèche are strongly discouraged and you can only consider using an (experienced) babysitter if she only takes care of your child or, if necessary, other infants of the same age.
Two types of surgery can be considered:
Cerclage (or banding) of the pulmonary artery. This is a “palliative” intervention, that is to say one that aims to temporarily limit the consequences of the anomaly without correcting it;
The closure of the VSD with a patch of pericardium or synthetic tissue. This is the “curative” and (normally) definitive intervention.
Their respective places have evolved considerably over time and currently, in developed countries, most CIVs are immediately closed by patch, without prior installation of strapping.
Cerclage of the pulmonary artery
During this intervention, the surgeon encloses the trunk of the pulmonary artery in a tissue sleeve in order to reduce its diameter. This narrowing is the cause of an increase in pressure in the right ventricle and therefore a decrease in the pressure gradient between the two ventricles. The amount of blood passing through the CIV is reduced, which relieves left ventricular failure on the one hand, and pulmonary hypervascularization on the other.
Closing under CEC
The approach is via median sternotomy (i.e. opening of the sternum). The intervention itself is done with the heart stopped, under extracorporeal circulation (CEC). The surgeon must open the heart to access its medial septum and the communication. The opening mode depends on the location of the VIC(s). As much as possible, the surgeon avoids opening a ventricular wall (in particular of the left ventricle) to avoid weakening this muscle which is still in work. VSD can be approached through the tricuspid valve after opening the right atrium or through the pulmonary valves after opening the pulmonary trunk. The communication is closed by a piece (“patch”) of synthetic fabric fixed by stitches on the right side of the interventricular septum. The synthetic fabric used is well tolerated and presents no risk of rejection. After a few months, it will be colonized by cells of the organism which will line it as they line the rest of the septum (endothelialisation).
Treatment by interventional catheterization
Closure by placement of an obstructive device during catheterization (thus without surgery) has become the common treatment for some ASD (atrial septal defect) or persistent ductus arteriosus. This technique is proposed for VSDs, in particular when they are located in the muscular septum, which is more difficult for the surgeon to access. Its realization is more difficult for perimembranous VSDs due to the proximity of the conduction pathways and the risk of occurrence of atrioventricular block (which may require the placement of a pacemaker).
Most CIVs can be considered as a one-time accident ("a finishing defect") whose risk of recurrence is close to that observed in the general population. As such, they do not justify genetic counselling. Genetic counseling, not related to the presence of CIV, but to the chromosomal abnormality that accompanies it, will be justified in the following situations:
CIV posterior linked to the existence of trisomy 21.
Subaortic VSD occurring in the setting of a 22q11 micro-deletion.
CIV observed within a polymalformative syndrome revealing trisomy 13, trisomy 18 or another genetic abnormality revealed by the fetal or neonatal karyotype.