Cardiothoracic surgery: overview
Cardiothoracic surgery encompasses all aspects of disease that can be managed surgically within the thorax. This includes primarily conditions of the heart, thoracic aorta, lungs, tracheobronchial tree, and conditions of the chest wall. Transplantation of the heart and/or lungs and mechanical circulatory support also fall under the remit of the speciality.
Cardiothoracic surgery is a highly specialized field and despite the extent of anatomical coverage, it is a small speciality with a relatively small body of consultants in the UK, with further divergence within the specialty to subspecialize either into cardiac or thoracic surgery. Within each subspeciality there are opportunities to further super-specialize. Due to the nature of the speciality, cardiothoracic surgery has always remained within a tertiary referral centre and commonly one that is also a major trauma centre. In the UK occasionally, a thoracic surgical unit may be at a different geographical location to a cardiac surgical unit. Therefore depending where you are posted, you may not necessarily see the full gamut of the speciality. In addition, a cardiothoracic surgical placement may not be part of your standard surgical rotation and extra effort may be required to organize such a placement (i.e. special study module, optional attachment, taster weeks). Therefore, if you are placed in a regional tertiary referral centre make the extra effort during your surgical attachments to organize some time within the cardiothoracic department. It may be your only exposure. You will gain the most from this during your later stages of surgical training, once you have mastered the generality of undergraduate surgical training.
Cases to see
Ischaemic heart disease (IHD)
This is the most common condition that is referred to a cardiac surgeon by a cardiologist. This referral may take place once medical therapy has failed and the patient remains symptomatic, or the extent/pattern of IHD warrants an early cardiac surgical referral. In addition, this may be either before or after an ACS or following an admission to hospital with unstable angina.
Valvular heart disease
Valvulopathy can affect any valve but commonly affects the left-sided valve (aortic and mitral). It can either be stenotic, regurgitant, or mixed. Valvular heart disease is the second most common pathology that is referred to the cardiac surgeon and therefore is a prevalent condition. Patients with mixed valvulopathy may have one valve with mixed pathology or more than one valve being affected at the same time.
Disease of the aorta
There is a large spectrum of disease that can affect the aorta but commonly this takes the feature of aortic ectasia where the aorta becomes aneurysmal. Connective tissue diseases (i.e. Marfan’s disease, Ehlers–Danlos syndrome, mixed connective tissue disease) 
the risk of aneurysmal change in the aorta. It is this aneurysmal change that causes greatest harm and the risk of aortic rupture. Once diagnosed, surveillance is paramount and surgical intervention is warranted if the patient is symptomatic. In the ascending aorta, if the diameter is >5 cm in a patient with connective tissue disease, female, or of South Asian ethnicity or >5.5 cm otherwise, elective surgery is indicated. This threshold is lower if the patient is undergoing a cardiac procedure for a different pathology (i.e. aortic valve replacement for AS). The threshold to >5 – 6 cm if the aortic arch is aneurysmal and >6.5 cm with an aneurysmal descending thoracic aorta.
Lung cancer
Thoracic surgeons are referred patients that are deemed operable or have a type and/or pattern of lung cancer than is amenable to surgical treatment. This is usually decided in an MDT, which takes place before the referral for surgical review. Lung cancer surgery is the brunt of the thoracic surgical workload and mostly includes tumours of the lung and also includes tumours of tracheobronchial tree and chest wall.
Benign thoracic disease
This encompasses all benign conditions of the tracheobronchial tree, lungs, mediastinum, and chest wall and includes conditions such as surgical management of tracheal strictures, pneumothoraces, pleural effusions, and empyemas.
Investigations and procedures to see
Coronary angiography
The best place to see how this is done and understand the technique is the cath lab in the cardiology department. The interventional cardiologists perform this procedure routinely. It assesses the two-dimensional (2D) anatomy and degree of stenosis within the coronary arteries. While you are in the cath lab you may also see some coronary angioplasties and coronary stenting. Angioplasty simply means restoring the patency of the blood vessel but stenting maintains patency. Once you understand the technique of acquiring these images, they can be viewed offline for each patient having a cardiac operation.
Transthoracic echocardiogram
This is a 2D representation of the heart and its structures. It allows for the assessment of valvular and ventricular function and through this the extent of valvular disease can be quantified.
Lung function tests
These provide an assessment of the patient’s baseline pulmonary lung function. They measure the FEV1 and the FVC, which are used to calculate the ratio of FEV1/FVC to assess the degree of lung disease (i.e. obstructive or restrictive) (see 
Chapter 30). It also plots flow–volume loops.
CT thorax
A CT scan is a common tool for radiological diagnosis and is mandatory in the diagnosis of lung tumours. Visit the radiology department to see how this is performed and then get familiar with the lung, mediastinal, and bone windows (which you can switch between), which allow for greater clarity to view the different tissue densities.
Operations to see
In addition to the operations listed in the next section, depending on the expertise of the unit, try to observe surgery of the aorta, trachea, and bronchial tree as well as cardiac and lung transplantation. Chest wall surgery is not common but can be graphic if it entails a large resection. Transplantation usually happens overnight and if it is during the day, do not miss the opportunity to witness it. Aortic surgery is complex and therefore can be a long, all-day case; be prepared for this, especially if it is descending thoracic or thoracoabdominal surgery.
Intensive care
(See Chapter 9.) During your placement in this speciality, it is important not to miss the opportunity to visit the cardiac ITU and/or the thoracic HDU. All patients following a cardiac operation will spend the first day or two on the ITU, and this is an opportunity to familiarize yourself with the extent of haemodynamic and respiratory support that some patients require. Try to familiarize yourself with some of the common drug used (e.g. adrenaline (epinephrine), noradrenaline (norepinephrine)) and types of respiratory support (mechanical ventilation, CPAP, etc.). Once you have spent some time on the cardiac ITU, you will find that most patients will recover very quickly and be transferred to ward. In thoracic surgery, most patients will be transferred to HDU mainly for postoperative monitoring. These patients are at high risk of developing early complications hence more intensive monitoring is required for a day or two.
Cardiothoracic surgery: in clinic
Attending a cardiac outpatient clinic will provide the best opportunity to hone your skills of obtaining a focused cardiovascular history and examination. In a thoracic outpatient clinic, you will be able to practise taking a respiratory history and perform examinations. Invariably, a patient with a valvular lesion or IHD will attend a cardiac clinic and one who has been diagnosed with a lung tumour will attend the thoracic clinic. In addition, this is a good opportunity to review patients post major cardiac and thoracic surgery, as you will get an opportunity to see follow-up patients. Preoperative assessment clinic is a good opportunity to practise your history and examination as well as review all the preoperative investigations prior to surgery.
Cardiac history
Within the HPC, if it is related to pain follow the SOCRATES scheme. If there is angina or dyspnoea, confirm exactly when they come on and what the patient was doing at the time they get the symptoms. Is it reproducible? Confirm if there is evidence of rest or night pain, which indicates more unstable and severe angina. Establish symptoms of heart failure such as orthopnoea or paroxysmal nocturnal dyspnoea and confirm any history of peripheral oedema especially towards the end of the day. Key features in a cardiac history should include the risk factors the patient has for developing a cardiac condition. Common risk factors: include diabetes, smoking, hypercholesterolaemia, hypertension, male sex, age, IHD, and significant family history of heart disease. Within PMHx, with valvular heart disease establish if they have had rheumatic fever as a child. Establish their respiratory status by specifically asking them about asthma, COPD/emphysema, and TB. Within the SHx, try and establish their capabilities of independence and activities of daily living. Clarify the extent of help they receive with these tasks and also address their mobility and overall frailty.
Thoracic history
Lung cancer is common, and the PC may usually be as simple as shortness of breath (SOB). Pain is not a common association. In the HPC try to tease out other associated symptoms such as duration and progression of dyspnoea, cough, haemoptysis, and constitutional symptoms including weight loss, anorexia, and night sweats. Also, identify risk factors such as history of smoking (calculated the number of pack-years smoked), and type of occupation (miners and those who have worked in the heavy dye industry may have been exposed to carcinogenic chemicals dyes, etc.) The PMHx follows the same criteria as a cardiac history. In the SHx, again identify the extent the condition impinges on activities of daily living and through this, assess their general state of health (are they physically capable to undergo a major operation?).
Cardiothoracic surgery: in the emergency department
When a patient presents to the ED with a cardiothoracic problem, it is likely to be a life-threatening emergency in the resuscitation unit.
Stanford type A aortic dissection
This is a cardiac surgical emergency. A tear in the intima creates a dissection plane between the intima and media of the aortic wall and blood traverses through this plane, creating a false lumen. A type A dissection is one that originates anywhere between the aortic valve and the left subclavian artery and hence within the pericardium. The dissection can progress from the point of origin proximally or distally and can involve the entire aortic vasculature. Depending on the extent of the tear, complications include cardiac tamponade, aortic valve incompetence, MI (involving the coronary ostia), stroke, rupture into the pleura, or compromise of any of the aortic branches. Branch compromise can 
stroke, upper limb arterial insufficiency, paraplegia, lower limb ischaemia, renal ischaemia, or mesenteric ischaemia.
Risk factors for an aortic dissection include hypertension and connective tissue disorders. Patients with a bicuspid aortic valve are known to have a higher incidence of aortic dissection. A CT aortogram aids in accurate diagnosis of an aortic dissection. However, subtle feature may include widening of the mediastinum on CXR. In addition, a TOE can assess the aortic valve, exclude tamponade, and confirm a dissection. At times, a dissection is only diagnosed in the cath lab during a coronary angiogram for a suspected coronary event. (See Fig. 33.1.)
Surgery is indicated for all patients with a type A dissection and the goals of surgery are to re-establish the true lumen, obliterate the false lumen, maintain aortic valve competence, and re-establish coronary arterial blood flow.
Chest trauma
Chest trauma is common and can either be blunt or penetrative. Life-threatening injuries can be remembered by ATOM FC:
• Airway disruption
• Tension pneumothorax
• Open pneumothorax
• Massive haemothorax
• Flail chest
• Cardiac tamponade.
Each patient assessed in the resuscitation department needs to be done systematically as per the Advanced Trauma Life Support® (ATLS®) principles. You will also see thoracostomy tubes (chest drains) inserted.
Potentially life-threatening injuries can be remembered by PODCAST:
• Pulmonary contusion
• Oesophageal disruption
• Diaphragmatic tear
• Cardiac contusion
• Aortic disruption
• Sternal and rib fractures
• Tracheobronchial disruption.
Traumatic disruption of the aorta occurs in any type of deceleration injury (i.e. road traffic accident or a fall). Oesophageal injures and diaphragmatic tears1 can be difficult to diagnose. With all chest trauma one should have a high index of suspicion for these injuries. One of the most dramatic scenes in the resuscitation departments in trauma centres is clamshell thoracotomies done in absolute emergencies. The procedure exposes both thoracic cavities to allow access to the heart for cardiac massaging and managing profound hypotension or cardiac arrest. These patients will need to be transferred to theatre imminently.
Reference
1. Wilson E, Metcalfe D, Sugand K, et al. (2012). Delayed recognition of diaphragmatic injury caused by penetrating thoraco-abdominal trauma. Int J Surg Case Rep 3(11):544–7.
Cardiothoracic surgery: in theatre
Coronary artery bypass graft surgery
This is the commonest procedure performed by a cardiac surgeon and essentially involves bypassing the area of coronary stenosis with a suitable conduit, usually long saphenous vein harvested from the leg. The direction of flow within the vein is inverted (to prevent the valves within the vein restricting flow) and the distal anastomosis is constructed onto the coronary artery distal to the area that is affected, with the proximal anastomosis onto the proximal ascending aorta. Therefore blood flow is re-established from the proximal ascending aorta, beyond the coronary stenosis to a myocardial territory that previously had inadequate blood supply (i.e. ischaemia).
Surgery on the heart can be performed with the heart beating or with the heart stopped. However, beating heart operations are limited to mainly CABG. Most cardiac procedures are performed while the heart is stopped and therefore the role of the cardiopulmonary bypass (CPB) machine is essential to keep the patient alive during the length of the procedure. In essence, the CPB machine drains the venous blood from the patient, the blood is temperature controlled, oxygenated, filtered, and then returned to the arterial system. During cardiac surgery, an optimum operating environment is when there is a motionless and bloodless operative field, in which the heart needs to be arrested. A cross-clamp is placed across the ascending aorta proximal to the arterial return from the CPB machine. The heart is then arrested with a potassium-rich solution called ‘cardioplegia’. This is then administered intermittently during the operation to maintain diastolic arrest which reduces the metabolic demands of the heart. Following cardioplegia, the heart regains its intrinsic activity on reperfusion when the aortic cross-clamp is released at the end of the main procedure. The patient is gradually weaned off the CPB machine, and the work of the heart and lungs are gradually transferred from the machine back to the patient.
Aortic valve replacement
This is one of the most common open-heart operations. An open-heart operation is one where one or more chambers of the heart are opened to the atmosphere as part of the procedure and therefore the patient is liable to have an air embolism if the chambers of the heart are not de-aired at the end of that segment of the procedure. The aortic valve is routinely replaced but aortic valve repair is also susceptible to pathologies. During valve replacement, a biological (e.g. bovine or porcine) pericardial tissue valve or a mechanical valve can be implanted. The ascending aorta is opened to access the native aortic valve. The valve is debrided and explanted off the aortic annulus and the new valve is stitched in place. Finally the aorta is closed, the heart is de-aired, and the aortic cross-clamp is removed.
Mitral valve repair/replacement
The mitral valve is repaired whenever possible. A repair maintains part of the valvular apparatus, which includes the chordae tendineae and papillary muscles. The type of repair depends on the extent and type of the underlying pathology. When a repair is not suitable, the mitral valve too can be replaced with a tissue or mechanical valve.
The approach to the mitral valve can be transseptal or directly into the left atrium through Sondergaard’s groove.
Lobectomy
This refers to the surgical removal of one or more lobes of the lung that has a lung tumour within it. Preoperative planning will identify which lobe the tumour is in and if there is any invasion into another adjacent lobe or if there is any local spread to surrounding tissue or lymph nodes. The right lung consists of three lobes and the left has two lobes. The left lung lacks a middle lobe but has a smaller lobe called the lingula. The lobes are separated by inter-lobar fissures. These fissures aid in excision of an entire lobe, as the surgical plane follows the inter-lobar fissures and dissection continues down into the hilum to identify the lobar bronchus, veins, and pulmonary arteries that supply the lobe that is to be excised. Once the lobectomy is complete, a series of lymph nodes are sampled for pathological stages of the tumour.
Video-assisted thoracic surgery (VATS)
This refers to the equivalent of laparoscopy surgery but in the chest, and is a form of minimally invasive surgery. Ideally three incisions are made and access gained through appropriate intercostal spaces; the camera port is placed through one and surgical equipment through the other two ports. Procedures commonly performed using VATS include lobectomy, wedge resections, pleurectomy, bullectomy, and lung biopsies for diagnosis. VATS offers a better view of the anatomy and surgical procedure being performed compared to one that is accessed via a thoracotomy, due to the restricted space provided.
Bronchoscopy
This is a key skill and is performed in every patient prior to undertaking the main operation. It allows for visual assessment of the tracheo-bronchial tree in case of tumour invasion. Brush cytology and biopsies can be sampled for microscopic diagnoses. (See Fig. 33.3.)
Cervical mediastinoscopy
This is a procedure that is performed mainly for diagnostic purposes. It is performed through a small transverse incision 1–2 cm above the suprasternal notch. Dissection is made down to the trachea and a mediastinoscope is placed in the pretracheal plane. It allows for multiple lymph node biopsies to be taken for diagnosis and staging of tumours.
Intercostal chest drain insertion
This is a common surgical procedure and every doctor should know the principles of this procedure and be familiar with it. It is performed in the safe triangle—the area between latissimus dorsi, pectoralis major, apex of the axilla, and fifth intercostal space within the anterior axillary line. The procedure is performed by blunt dissection using artery forceps and a key step is digital palpation after penetrating the pleural cavity to push the lung away. This protects the lung from penetrative trauma as the chest drain advances into the pleural cavity. An appropriately sized drain is placed to the apex (for air) or to the base (for fluid) and secured with an external suture.
Cardiothoracic surgery: in exams
As cardiothoracic surgery is a specialized field, you will not get examined extensively on this speciality per se. However, the medical conditions that warrant referral to cardiothoracic surgery will certainly get examined and these are what you should be confident about (i.e. angina, AS, AR, lung cancer, pneumothorax, pleural effusions). In the history stations, it is common to have a PC of chest pain or SOB. With chest pain you should go down the cardiac history route, but with SOB it could either be cardiac or respiratory in origin. You may also get a history on palpitations so remember to ask about frequency, duration, preceding events, and associated symptoms (i.e. SOB, chest pain, and associated PMH such as TIA/stroke). Be confident with a full CVS and respiratory examination and their separate components. It is highly likely in an OSCE that you will be asked to examine the chest or precordium. The clue to which system you need to examine will be in the question, where you may be offered a short history. There are plenty of patients with asymptomatic murmurs and they are commonly asked to attend an OSCE, so be confident in identifying a systolic from a diastolic murmur (it is likely to be a systolic murmur). Practise the additional manoeuvres you can perform to elicit clearer heart sounds or murmurs (i.e. roll the patient into the left decubitus position for mitral murmurs, sit the patient upright and lean them forward for AR, left-sided murmurs are enhanced on expiration and right-sided murmurs are enhanced on inspiration). See Table 33.1.
Table 33.1 Recent research trials
| Year |
Trial |
Comments |
|
2009
NEJM
N = 2368 |
Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) |
Patients with T2DM + stable CAD that are CABG candidates, CABG + OMT reduced the rate of CV events compared to optimal medical therapy (OMT) alone, but no difference in the PCI cohort |
|
2011
NEJM
N = 1212 |
Surgical Treatment for Ischemic Heart Failure (STICH) |
In ischaemic cardiomyopathy with LV ejection fraction ≤35%, CABG (added to OMT) only reduces cardiovascular-related deaths after 5 years and all-cause mortality after 10 years |
|
2012
NEJM
N = 1900 |
Future Revascularization Evaluation in patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) |
Among diabetic patients with multivessel CAD, CABG reduces the rate of death + MI compared to PCI, but causes rate of stroke |
|
2013
JAMAN = 1021 |
Mitral Regurgitation International Database (MIDA) |
Retrospective study: in chronic flail MR, early surgery was associated with improved survival compared to medical management |
Cardiovascular system examination
(See ‘Cardiovascular examination’ pp. 900–904.) Concentrate on practising a complete CVS exam. There is enough time in clinic to do this especially if you are seeing a new patient. A full CVS examination should include the assessment of the patient from the end of the couch, assessment of their peripheries (capillary refill time, peripheral warmth, and examination of their hands to identify features of cardiovascular disease) before moving onto examining the chest. You can conclude your CVS examination by examining the peripheral arteries and assessing for signs of heart failure (i.e. peripheral and/or sacral oedema and auscultating the lung bases for crepitations). If you are asked to examine the chest, then this should include the inspection, palpation, percussion, and auscultation (IPPA) model of the chest only and not a full CVS exam. Examination of the chest should be limited to the CVS and not be overlapped with the respiratory system. You may be specifically asked to examine the precordium.
In examining the precordium, do not rush through inspection (looking at chest deformities, i.e. pectus excavatum and carinatum), previous incisions, and visible pulsations. Palpate and show that you are confirming the position of the apex beat (by counting from the manubriosternal joint). Also take time in palpating for heaves or thrills (palpable murmur). Being able to palpating a thrill is not common but look out for it, as once you have felt it, it is indistinguishable. On auscultation, first identify which heart beat corresponds with the pulse by palpating the carotid artery at the same time (the pulse corresponds with the first heat beat). If you then hear a murmur, identify if this in the systolic phase or the diastolic phase of the cardiac cycle. Once this is established, try to identify if its ejection is systolic (AS), pansystolic (MR), early diastolic (AR), or late diastolic (MS). The latter two are more difficult to identify. Right-sided valve lesions are less common and tend to coincide with congenital abnormalities.
Respiratory examination
(See ‘Respiratory examination’ pp. 905–909.) The complete respiratory examination is a full assessment of the patient as per the CVS examination, which includes assessment from the end of the couch, examination of the hands, examination of the neck for cervical lymphadenopathy (indicative of lymph node involvement/metastases) and palpation for the trachea (displacement and tracheal tug), before focusing on the chest. Examination of the peripheral arteries is not necessary. To be more focused on the chest, examination includes the IPPA model.
Do not forget to examine both the anterior and posterior chest including the axilla. The thoracic clinic will allow you to assess patients post major thoracic surgery and may have patients with a previous thoracotomy scar. Some patients may have had lobectomies, whereas others may have had a pneumonectomy (complete resection of the lung on one side). These patients have interesting and rare clinical signs so look out for them.
