Conference Lectures

John Jerstice
UK

Anaesthesia for Cardiological interventions in the Catheterisation Laboratory.

There is an increasing trend to performing invasive procedures in the catheterisation lab. This was initially due to a need to provide care for patients who were deemed too sick for surgical intervention. With increasingly good and effective devices, and improved imaging with x-ray and trans-oesophageal echo (especially 3D), these interventions are now regarded as the primary mode of treatment.
In order to perform these interventions it is usually preferable to give the patients a general anaesthetic. This is primarily to facilitate the TOE, but to also to improve patient experience. In my experience general anaesthesia improves efficiency as the operators have better control of the procedure and improve quality of outcome.
There are a number of factors to consider when providing anaesthesia for these interventions.
A major consideration is the physical environment where the procedure is to be carried out.
Catheterisation laboratories are often remote from the theatre complex.
This means that all facilities that are available for giving a safe anaesthetic in theatres should be replicated in the catheterisation lab.
Most theatres in the UK have anaesthetic rooms; this is usually not an option in the catheterisation Lab. The patient will have to be anaesthetised in the treatment room. The patients are usually anaesthetised on the X-ray table. These are flat and often do not have a tilt mechanism, therefore care needs to be taken in patients who have a risk of reflux or regurgitation.
The intervention labs are often cold. Active patient warming is advised. A forced air system is the most practical due to being radio translucent.
There is usually no dedicated recovery room available. So a controlled area with oxygen and monitoring should be identified before the start of the procedure. The staff, usually have limited experience of dealing with patients recovering from a general anaesthetic, so prior education is needed before starting an intervention program.
Equipment availability is an important consideration before starting an intervention list.
All the usual anaesthetic equipment should be present. This should include airway management equipment, anaesthetic machine, ventilator and monitors. Consideration as to gas supplies is important, as supplies of piped medical air and oxygen may not be available, therefore, cylinders may need to be used.
The storage and supply of anaesthetic agents should be worked out before the start of treatment.
Warm fluids and fluid warming devices should be available.
In the event of patient collapse or arrest, a worked out resuscitation process and pathway is advised. HDU or ITU support may be required.
A close working relationship with the interventional cardiologist is very important. This leads to a proficient and experienced team, which in turn leads to good patient experience and outcome. I would suggest a regular senior anaesthetist is an important factor in all catheterisation lab interventions.

Having looked at some of the general considerations of anaesthesia in the catheterisation lab, I will look in more detail at specific interventions. It should be noted that the anaesthetic technique should be tailored to the patient, the physical environment and the technique of device deployment.

 

Patent Foramen Ovale Closure Devices

Background considerations.
The frequency of PFO occurrence was until recently thought to be quite low in the general population. With increasing use of ECHO in the investigation of TIA and stroke, especially in the younger population, the incidence of PFO is surprisingly high. The incidence of PFO is estimated at 25% of the adult population. A PFO is present in 40% of patients presenting with stroke.
It is suggested, at present, that a patient with a PFO less than 4mm is unlikely to benefit form closure. Closure of a PFO of more than 4mm leads to a reduction in TIA and stroke rate, with possible benefit in the treatment of migraine headaches.
The heart is usually approached from a venous femoral puncture. A guide wire, using ECHO and X-ray control, is placed up the IVC and advanced through the right atrium and across the PFO. There is usually no need for measurement of PFO. The closure device is then advanced over the wire and across the defect. The first disc is pushed out and allowed to reform its shape (disc). This is then pulled back to sit against the left Atrial side of the PFO. The deployment sheath is then withdrawn a little to allow for the second disc to reform. The position is checked with the ECHO, making sure that the mitral valve is clear of the PFO closure device. Once checked and position confirmed then it is released and rechecked with the ECHO.

Patient Demographics
Tend to be younger patients (less than 50), who have presented having had a stroke or TIA. Investigations of the type and cause of the stroke by TOE show a PFO.
Patients usually have preserved myocardial function if the PFO is small to moderate in size.
The patients usually have some neurological deficit. This deficit is stable following an embolic event across the PFO.

Points of Anaesthesia.
Patient warming (under body bair hugger) as catheterisation labs are cold.
Variable duration of procedure, in the region of 30mins to 90mins.
Standard monitoring:
NIBP, SaO2, EtCO2, Volatile.
ECG is usually displayed on the cardiology equipment and TOE so, usually no need for the anaesthetic machine as well.
IV access should be established, there should be no need for A-line or CVP.
1000ml Hartmann’s fluid should be sufficient.
Endotracheal tube should be used to allow for TOE.
Antibiotics to cover device deployment.
Usually Flucloxacillin 1g and Gentamycin 240mg but should be guided by local antibiotic policy and microbiology advice.

Recovery Area.
Little pain generally.
Oxygen via mask until fully awake.
Headache is frequent, treated with simple oral analgesics for example paracetamol.
Femoral access port is often left in, so patient has to lie flat until it is removed.

Post operatively.
Patients should usually be able to go the ward following the procedure.

 

Atrial Septal Defect Closure Devices

Background considerations.
Atrial Septal Defects are classed as part of Adult Congenital Heart Defects.
They are estimated as to being 6 to 10% of all congenital heart defects.
The most common ASD type is through the Ostium Secundum, this accounts for 75% of all ASDs. An ASD of greater than 9mm will give a significant shunt. There is a 2 to 1 ratio for female to male patients.
Patients tend to be younger (less than 50) who have presented with a stroke or TIA. Investigation of the cause of stoke with ECHO demonstrates the ASD.
Myocardial function is usually preserved with this group of patients. However, heart function should be assessed prior to treatment, to assess right heart function particularly.
Most patients have some neurological deficit as a result of stroke.
The heart is usually approached from a venous femoral puncture. A guide wire, using ECHO and X-ray control, is placed up the IVC and advanced through the right atrium and across the ASD. The ASD is measured with a balloon device and an appropriate size of closure device selected. The closure device is then advanced over the wire and across the defect. The first disc is pushed out and allowed to reform its shape (disc). This is then pulled back to sit against the left Atrial side of the ASD. The deployment sheath is then withdrawn a little to allow for the second disc to reform. The position is checked with the ECHO, making sure that the mitral valve is clear of the ASD closure device and to check for continued flow. Once checked and position confirmed then it is released and rechecked with the ECHO. If significant flow remains then a second device may be deployed.

Points of Anaesthesia.
Patient warming (under body forced air) as catheterisation labs are cold.
Variable duration of procedure 45mins to 120mins, can be a lot longer due to the use of multiple devices.
Standard monitoring:
NIBP, SaO2, EtCO2, Volatile.
ECG is usually monitored by cardiology and TOE so usually not needed on the anaesthetic machine as well.
IV access should be sufficient. An A-line or CVP line may be indicated if the patient has poor myocardial function.
1000ml Hartmann’s fluid should be sufficient for maintenance and fluid replacement.
Endotracheal tube is necessary to allow for TOE.
Antibiotics to cover device deployment.
Usually Flucloxacillin 1g and Gentamycin 240mg but should be guided by local antibiotic policy and microbiology advice.

Recovery.
Little pain generally.
Oxygen via mask until fully awake.
Headache is frequent, treated with simple oral analgesics for example paracetamol.
Femoral access port is often left in, so patient has to lie flat until it is removed.

Post operatively.
Patients should usually be able to go the ward following the procedure.

 

Ventricular Septal Defect Closure Devices

Background considerations.
VSD may occur as a congenital defect. Care should be taken to investigate the heart fully as there are often other cardiac problems. These cases often present in childhood and are managed by the paediatric team.
In adults, the presentation is usually by two mechanisms. First with investigation of stroke, where a small VSD is found on ECHO. Second following a myocardial infarct. Patients presenting with post infarct VSD tend to be older patient with significant myocardial compromise.
Following the development of a post infarct VSD, very careful myocardial assessment should be made. Common finding are a severely impaired LV function with left to right shunt. Right ventricular function can be badly impaired. Bi-ventricular failure may be present. Respiratory and renal function should be assessed due to frequent pulmonary oedema and secondary renal failure.

Once it has been decided that VSD closure is appropriate the closure requires catheterization of right and left heart. The heart is approached from the femoral artery and right internal jugular vein. A wire is fed across the VSD from left and right ventricles. Atrial septal puncture may also be required.

Points of Anaesthesia.
Patient warming (under body forced air unit) as catheterisation labs are cold.
The procedure has very variable duration from 60mins to 120+mins. There is often a trial of VSD closure with a balloon is order to assess heart function following a definitive closure.
Standard monitoring:
Initially NIBP, SaO2, EtCO2, Volatile.
ECG is usually monitored by the cardiologists and TOE so usually not needed for the anaesthetic machine as well.
A-line is needed due to haemodynamic instability and ACT sampling.
IV access 20g or 18g should be sufficient with 1000ml Hartmann’s fluid. Fluids may need to be restricted due to myocardial failure and fluid overload.
Endotracheal tube to allow for TOE.
Antibiotics to cover device
Usually Flucloxacillin 1g and Gentamycin 240mg but should be guided by local antibiotic policy and microbiology advice.

Recovery
Oxygen until fully awake.
The procedure is usually not painful afterwards.
Femoral access may be left in, so patient has to lie flat until removed.
There can be significant haemorrhage from cannulation site.
The patient may have haemodynamic instability.
The decision as to the extent of post intervention support should be worked out before the procedure. Interventions may be inotropes, ventilation in ITU or surgical intervention.

Post operatively
Patients will go to the CCU afterwards if the procedure is successful. Careful monitoring is required as further myocardial infarction can occur, leading to the displacement of the device. The change of blood flow following VSD closure can cause significant haemodynamic instability.

Mitral Valve Clips

Background considerations.
The Mitral clip is indicated for the reduction of functional Mitral regurgitation. The patients are older with a high risk from operation. Currently regarded as a risk high than 6% of peri-operative death.
Investigation with TOE demonstrates severe MR. Myocardial function is often very poor hence not suitable for surgery.
The patient may have significant co-morbidities, especially renal and respiratory dysfunction.
The Mitral valve is approached from a Femoral vein and an Atrial septal puncture. The mitral valve is approached from the left atrium.
The degree of MR reduction is assessed with ECHO (3D preferred) following deployment of the clip. If significant MR persists then a further device may be deployed.

Points of Anaesthesia.
Patient warming (under body forced air unit) as catheterisation labs are cold.
The procedure has very variable duration from 60mins to 120+mins. Duration of procedure may be extended if more than one clip is required.
Standard monitoring:
Initially NIBP, SaO2, EtCO2, Volatile.
ECG is usually monitored by the cardiologists and on the TOE machine so usually not needed for the anaesthetic machine as well.
A-line is needed due to haemodynamic instability and ACT sampling.
IV access 20g or 18g should be sufficient with 1000ml Hartmann’s fluid. Fluids may need to be restricted due to myocardial failure and fluid overload.
Endotracheal tube to allow for TOE.
Antibiotics to cover device
Usually Flucloxacillin 1g and Gentamycin 240mg but should be guided by local antibiotic policy and microbiology advice.

Recovery.
Oxygen until fully awake.
The procedure is usually not painful afterwards.
Femoral access may be left in, so patient has to lie flat until removed.
There can be significant haemorrhage from cannulation site.
The patient may have haemodynamic instability.

Post operatively.
Patients will go to the CCU afterwards. Careful haemodynamic monitoring is required. Myocardial function should improve with reduction of MR, however, complete valve failure may occur.

Left Atrial Appendage Closure Device

Background considerations.
This is a device for patients who have high risk of embolisation BUT cannot have anticoagulation. These are usually patients in AF with bleeding problem e.g. intra-cerebral.
The myocardial function is often preserved. However the patients may have significant co-morbidities.
The left Atrial appendage is approached via the femoral vein and an Atrial septal puncture. If there is a PFO this can be used for the guide wire. Deployment of the device is under fluoroscopy and ECHO control.

Points of Anaesthesia.
Patient warming (under body forced air unit) as catheterisation labs are cold.
The procedure has very variable duration from 60mins to 120mins.
Standard monitoring:
Initially NIBP, SaO2, EtCO2, Volatile.
ECG is usually monitored by the cardiologists and on the TOE machine so usually not needed for the anaesthetic machine as well.
A-line may be useful if there are predicted haemodynamic instabilities or poor myocardial function.
IV access 20g or 18g should be sufficient with 1000ml Hartmann’s fluid. Fluids may need to be restricted due to myocardial failure and fluid overload.
Endotracheal tube to allow for TOE.
Antibiotics to cover device
Usually Flucloxacillin 1g and Gentamycin 240mg but should be guided by local antibiotic policy and microbiology advice.

Recovery.
Oxygen until fully awake.
The procedure is not particularly painful afterwards.
Femoral access may be left in, so patient has to lie flat until cannula is removed.
Can have significant haemorrhage from cannulation site.

Post operatively.
Patients should be able to go to the ward afterwards.

Transcatheter Aortic Valve Implant

Background considerations.
Patients are older and deemed not suitable for operation. The patient selection is usually a joint assessment by the cardiologist and cardiac surgeon.
Myocardial function is often poor with significant LV dysfunction. The patients also often have significant co-morbidities.
Approach to the aortic valve is via the femoral artery. We have vascular surgical help for this, which has led to a low incidence of vascular damage and post procedural bleeding. The valve can also be approached for the apex of the left ventricle.
There will be a period of VT pacing when the device is deployed and significant haemodynamic instability can occur.
The worse case scenario is having to go on bypass. Cardiac surgeon and perfusion standby are available for salvage procedure, if deemed appropriate.

Points of Anaesthesia.
Patient warming (under body forced air unit) as catheterisation labs are cold.
The procedure has very variable duration from 60mins to 120+mins. Duration of procedure may be extended if there are problems with device deployment or need for surgical intervention.
Standard monitoring:
Initially NIBP, SaO2, EtCO2, Volatile.
ECG is usually monitored by the cardiologists and on the TOE machine so usually not needed for the anaesthetic machine as well.
A-line is needed due to haemodynamic instability and ACT sampling.
A CVP is also needed for monitoring and administration of inotropes. If required.
Large reliable IV access is needed, with 1000ml Hartmann’s fluid initially. Fluids may need to be restricted due to myocardial failure and fluid overload.
Endotracheal tube may be preferred for good control of the airway, especially during the period of VT.
Antibiotics to cover device
Usually Flucloxacillin 1g and Gentamycin 240mg but should be guided by local antibiotic policy and microbiology advice.

Recovery.
Oxygen until fully awake.
The procedure is usually not painful afterwards.
Femoral access may be left in, so patient has to lie flat until removed.
There can be significant haemorrhage from cannulation site.
The patient may have haemodynamic instability.

Post operatively.
Patients will go to the CCU afterwards unless there are complications. We do not have routine HDU or ITU bed availability.