Preoperative Planning
Multidisciplinary preoperative and detailed planning allows better outcomes for patients. Essential and reproducible plannification is primordial for an efficient treatment.18 Effective preoperative planning is essential to identify any further complications prior to surgery that could delay patient recovery.
Preoperative conditions such as chronic lung diseases, cerebrovascular disease, peripheral artery disease and chest wall abnormalities, lung irradiation and previous cardiac/lung surgery are specially emphasised within these minimally invasive approaches.
Routine preoperative evaluation test such as electrocardiogram, chest X-Ray, complete bloods laboratory tests, echocardiogram and angiogram are performed in the usual manner for full sternotomy counterparts. However preoperative investigations could differ slightly from the routine investigations for standard AVR.
Computed tomography (CT) has an important role in the preoperative study for these minimally invasive procedures. CT allows better understanding of the anatomy and the safer delivery of either procedure. The CT gives us information about the lungs, airway, chest wall and mediastinum, including heart and great vessels. Different entities will preclude a challenging but not impossible procedure, such as lung adhesions, diaphragm paralysis and chest wall abnormalities with kyposcolisosis, pectus carinatum or pectus excavatum. Those pathologies might change the initial planned approach. In patients with previous cardiac surgery or chest wall irradiation, a chest CT conveys the distance between the posterior sternal table and right ventricle. The presence of patent coronary bypass grafts crossing the midline is particularly hazardous. For the UHS approach, CT scan confirms to which intercostal space to extend the J.
For the RAT approach, the CT scan also facilitates important information regarding the aorta and the relationship with the sternum. By noting which intercostal space is closest to the tip of the right atrial appendage, the preferred intercostal space is identified during the RAT approach. In essence, the RAT procedure is more favourable if:
Peripheral vascular and cerebrovascular disease increases the risk of stroke and embolisation. Careful assessment of the vascular system is carried out. CT angiogram is performed if suspicious or elevated risk of stroke or embolisation due to retrograde perfusion through peripheral cannulation is anticipated. Arteriosclerosis and calcium plaques in the aorta help us to choose different strategies for cannulation sites. Smooth, calcified plaque is less hazardous than soft or irregular plaque. In addition, the relative size and tortuosity of the iliofemoral vessels on angiogram are important factors in selecting the appropriate arterial cannula. Sealant devices such as angio-seal® are not recommended after preoperative angiogram because it will be difficult to perform femoral cut-down and subsequent cannulation in the procedure. In a patient with a history of stroke or transient ischaemic attack, duplex scanning of the carotid and vertebral arteries is obtained.
Hybrid Procedures
As growing expertise and number of procedures performed minimally invasive, the hybrid procedures are being explored. Pre-existing coronary disease does not contraindicate minimally invasive approaches as hybrid or staged procedures can be performed with good and comparable results. Different studies have evaluated the safety and benefit of these procedures. However, further prospective randomised controlled trials needs to be addressed to clarify which is the better approach whether staged/hybrid percutaneous coronary intervention (PCI) and AVR via minimal invasive or full sternotomy combined procedure AVR and coronary artery bypass graft.24