Preoperative assessment and surgical techniques
Heart valves function was assessed by transthoracic and transoesophageal
echocardiography. In the early years of our experience all patients
underwent preoperative CT angiogram of the whole aorta to evaluate
femoral access, aorto-iliac axes and the size of aortic root and the
ascending aorta. In the last four years, CT scan was performed only in
case of redo procedures and clinical suspicion or evidence of severe
atherosclerotic disease. Coronary arteries were assessed by coronary
angiogram.
Most of the operations (93%) on the atrioventricular valves in our
institute were performed through right mini-thoracotomy (MICS). In some
cases, median sternotomy was performed.
Main reasons for a sternotomy approach were: left ventricular ejection
fraction<25%, presence of pleural adhesion for previous
thoracic operations or chronic disease, severe chronic obstructive
pulmonary disease, severe peripheral arterial disease, active
endocarditis with abscess involving the mitro-aortic continuity [1].
Right anterior thoracotomy was performed through a 5-7 cm skin incision
placed at 4th intercostal space. In men, the incision is usually
immediately above the nipple. In women with pronounced breasts the
incision can be made in the sub-mammary sulcus. In the case of a small
and not very pronounced breast in women and in all men, a periareolar
incision can be made. Two trocars were used, one for the camera in the
third intercostal space, and one for CO2 delivery in the fifth space.
At the beginning of our experience, the surgical operation was performed
on direct vision and video assistance, while, recently, we have move
towards a totally endoscopic procedure (n=17, 25%).
All interventions were performed with cardiopulmonary bypass with
peripheral cannulation.
An incision of about 4 cm was performed at the level of the groin, with
exposure of the femoral vessels. The femoral artery was cannulated using
the Seldinger technique with a 17-19 Fr Bio-medicus cannula (Medtronics,
Minneapolis, MN 55432-5604 USA) or a 22 EOPA cannula (Medtronics,
Minneapolis, MN 55432-5604 USA). The choice of cannula was determined by
the diameter and characteristics of the femoral artery. When an endo
aortic balloon was used, the femoral artery was cannulated with a 21-23
Fr EndoReturn cannula (Edwards Lifesciences, Irvine, CA 92614 USA).
Aortic clamp and cardioplegia delivery was achieved by Endoaortic
balloon or direct cross clamp of the ascending aorta with a Chitwood or
a Cygnet vascular clamp. In the first scenario a Y shaped 21 or 23 F
cannula was used. The decision between these two different techniques
was based on the anatomy of the sinotubular junction, the
aorto-iliac-femoral anatomy and chest conformation. Generally, all redo
operations were performed using an endobaloon aortic clamp.
A double venous cannulation has been invariably used. A 14 Fr cannula
(Medtronics, Minneapolis, MN 55432-5604 USA) was usually inserted
percutaneously and with the Seldinger technique into the right internal
jugular vein and advanced into the superior caval vein. Through the
femoral vein a 23-25 Fr venous cannula (LivaNova, London, W2 6LG,
United Kingdom) was positioned at the level of the inferior vena cava.
Positioning of the cannulas was guided by transoesophageal
echocardiogram.
The tip of the cannula in the superior vena cava laid at superior
atriocaval junction, while the tip of the cannula in the inferior vena
cava 1 cm beyond the inferior atriocaval junction, in the right atrium.
Two types of pumps for cardiopulmonary bypass have been used: in the
first part of the experience a roller pump has been used, subsequently a
centrifugal pump has been used instead. In all interventions, before
right atriotomy, an active venous drainage (vacuum) was used, the
intensity of the venous drainage ranges from -20 to a maximum of -40
mmHg.
In all cases caval veins were not snared nor occluded from the inside
and the venous drainage was adjusted to avoid air suction while allowing
a satisfactory exposure of the tricuspid valve. Cardiopulmonary bypass
was generally conducted in normothermia with the use of normothermic
blood cardioplegia. In case of redo procedures or use of endoaortic
balloon, crystalloid custodial cardioplegia was used and mild systemic
hypothermia was established (32°C).