Case history

A 72-year-old female patient has been scheduled for TAVI for aortic stenosis, which has been classified as severe on echocardiography. You have been asked to anaesthetize her for this procedure.

What are the indications for performing an aortic valve replacement using the transcatheter aortic valve insertion technique?

◆ The operative morbidity in patients undergoing AVR through sternotomy and CPB, who have concomitant LV dysfunction, renal disease, respiratory disease, and previous sternotomy, increases from 4% in the population without these comorbidities to approximately 22%

◆ Based on the increased risk, NICE produced guidelines on those patients who should be considered for a TAVI procedure:

1 A EuroSCORE of >20 (i.e. the percentage of predicted operative mortality for cardiac surgery)

2 Severe respiratory disease

3 Refused surgery by two cardiac surgeons

4 Previous sternotomy and patent coronary bypass grafts (‘hostile chest’)

◆ The European Society of Cardiology recommendations are outlined as follows:

1 TAVI should only be undertaken following assessment by both cardiologists and cardiac surgeons

2 TAVI should only be performed in hospitals with cardiac surgery services on site

3 TAVI is indicated in symptomatic patients who have been refused surgery and who are expected to achieve an improvement in quality of life and have a life expectancy of >1 year.

What are the contraindications to transcatheter aortic valve implantation?

◆ An estimated life expectancy of <1 year

◆ Comorbidities likely to limit the quality of life, regardless of TAVI success

◆ Disease of other valves which require surgical repair

◆ An inadequate aortic valve annulus size (i.e. very small or very large)

◆ LV thrombus

◆ Active endocarditis

Relative contraindications include:

◆ Bicuspid valve

◆ Untreated coronary artery disease

◆ Cardiovascular instability

◆ LV ejection fraction of <20%.

There are three different approaches to TAVI that can be considered by the TAVI team:

◆ Transfemoral (TF)

◆ Transaortic (TAo)

◆ Transapical (TAp).

TF TAVI is the most straightforward and commonly used approach, involving bilateral groin punctures. Those suitable for TAVI, but with small femoral vessels or with atheromatous disease of the femoral vessels or the abdominal or thoracic aorta, may be considered for TAo TAVI. This is done via a small anterior upper right thoracotomy or an upper sternal wound. However, if the ascending aorta is inaccessible via either of these wounds or the ascending aorta is heavily calcified or atheromatous, then TAp TAVI, via a small left thoracotomy over the apex of the heart, may be possible.

Your patient has met the above criteria for aortic valve replacement using a transcatheter aortic valve implantation technique. What are the potential advantages to her of having her procedure in this manner?

◆ A full sternotomy is not required: this has implications for reduced post-operative pain and recovery time. There is a lower incidence of post-operative wound infection

◆ No need for CPB and the associated complications

◆ Reduced stay in critical care and reduced hospital stay: these patients would have previously been in the subgroup of patients who had prolonged periods of post-operative mechanical ventilation and critical care management.

Your patient has severe respiratory disease in the form of chronic obstructive pulmonary disease. She has symptomatic aortic stenosis, chronic kidney disease stage 3, and a EuroSCORE of 23. How would you approach this patient’s perioperative care?

Preoperative assessment

◆ A thorough history and examination, ensuring that the medical therapy is optimized for all comorbid conditions

◆ A focused anaesthetic history and examination

◆ A 12-lead ECG

◆ Haematological and biochemistry blood tests

◆ A blood sample sent to blood bank for cross-matching

◆ A detailed transthoracic echocardiogram

◆ CXR

◆ Gated CT angiogram of the aortic valve, thoracic and abdominal aorta, and iliofemoral vessels

◆ Coronary angiography ± angioplasty may be indicated

◆ Aspirin is prescribed preoperatively

◆ No sedative premedication is generally required, but, on an individual basis, a light, short-acting sedative may be indicated.

How would you prepare to anaesthetize your patient for her transcatheter aortic valve implantation?

◆ Ensure familiarity with the facilities provided for TAVI procedures, as these are often carried out in distant or isolated sites where additional help is not readily available. The facility (usually a cardiac catheter laboratory or hybrid theatre) should therefore have a piped gas supply, scavenging capability, anaesthetic machines, difficult airway equipment, access to anaesthetic and emergency drugs, and full patient and anaesthetic monitoring equipment

◆ The facility should also contain some means of supporting the circulation mechanically, e.g. with an intra-aortic balloon pump (IABP), an ECMO circuit, or a CPB circuit, with a perfusionist dedicated to the facility

◆ Anaesthetic and emergency drugs should be prepared and be ready for use prior to the patient’s arrival in the anaesthetic room

◆ The monitoring equipment, anaesthetic machine, and emergency equipment should be checked to ensure adequate function and identify any potential problems

◆ In working in an isolated environment with a team of cardiothoracic surgeons, cardiologists, pacing technicians, and catheter laboratory staff, it is especially important to have a comprehensive team briefing. Everyone has to be aware of, and agree with, the escalation plan and the level that treatment will be taken to for each individual patient, in the event of complications arising.

Can you outline the intraoperative management of this patient?

◆ Most procedures are carried out under general anaesthesia, but, in a small subset of patients, it may be possible to perform TF TAVI under local anaesthesia and sedation

◆ Monitoring should be established, and a large-bore peripheral cannula sited

◆ An arterial line should be placed prior to induction

◆ Following induction and tracheal intubation, central venous cannulation is performed

◆ A urinary catheter is inserted

◆ Remote defibrillator pads must be attached

◆ Temperature monitoring and active maintenance of normothermia with patient- and fluid-warming devices

◆ 150 U/kg of heparin is given (aiming for an ACT of >300 s) after the initial vessel punctures are made

◆ TOE (ideally three-dimensional) is used, in conjunction with radiological screening, to permit constant visualization of the aortic valve throughout the procedure, thus assisting in the correct placement of the replacement valve.

Outline the post-operative plan

◆ The patient will be extubated at the end of the procedure, unless there has been a complication

◆ Admission to critical care post-operatively is advised for a period of close monitoring

◆ Analgesia can be provided with the use of a long-acting local anaesthetic to the operating site (local infiltration and intercostal nerve blocks, as indicated) and simple analgesics, e.g. paracetamol. Long-acting opiates may be required for the TAo and TAp patients

◆ Antiplatelet therapy is required.

No procedure is without risk, and it is imperative that you are aware of the potential risks associated with a transcatheter aortic valve implantation in order to identify and manage them swiftly. Can you identify the major risks of the transcatheter aortic valve implantation procedures?

◆ The technique involves the passage of a wire across the aortic valve, and then a balloon valvuloplasty is performed to dilate the valve. At this point, rapid ventricular pacing is initiated to reduce the LV ejection and cardiac motion; this can result in prolonged cardiovascular instability, possibly requiring inotropic support and/or mechanical support

◆ TAVI placement can result in an obstruction of the coronary blood flow, causing ischaemia of the myocardium. A rapid diagnosis on coronary angiography and stent deployment can be lifesaving

◆ Haemorrhage: blood and blood products should be easily available from blood bank. Cardiothoracic surgeons can deal with haemorrhage from chest wounds, whilst vascular surgeons may be required to assist if there has been damage to the femoral vessels

◆ Pericardial tamponade: the echocardiographer will diagnose this quickly on TOE, and relief, either by percutaneous drainage or by an open procedure, may be required

◆ Stroke due to embolization of atheromatous plaques from the aorta

◆ Arrhythmias and, in particular, complete heart block: the temporary ventricular pacing wire used for the procedure can be left in situ, if required.

Summary

Patients selected for TAVI procedures are high-risk surgical candidates with multiple comorbidities. They require a comprehensive preoperative assessment and optimization carried out by a multidisciplinary team, consisting of cardiac anaesthetists, cardiac surgeons, and cardiologists. Anaesthesia is conducted in unfamiliar surroundings in remote locations, requiring forward planning to ensure equipment and appropriate staff are immediately available. The technique requires coordinated teamworking of the cardiac anaesthetists, cardiac surgeons, cardiologists, and catheter laboratory staff. Full knowledge of the potential complications and appropriate management are essential for patient safety in this setting.

Background

Learning outcomes

CPD matrix matches