Advice

Technology overview

Technology overview

This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.

About the technology

CE marking

Endosense SA was awarded a CE mark for the original TactiCath force‑sensing ablation catheter as a class III device in 2009. This was superseded by the third generation TactiCath Quartz ablation catheter, which was CE‑marked in 2012.

Endosense SA was acquired by St Jude Medical in August 2013. St. Jude Medical was awarded a CE mark for the TactiCath Quartz in 2014, with the current certification dated October 2015.

The TactiCath Quartz catheter requires the TactiSys Quartz system with analysis software and display workstation to visualise the contact force information. Endosense SA was awarded a CE mark for the TactiSys Quartz system as a class IIb device in 2012.

Current certifications for TactiCath Quartz and the TactiSys Quartz system expire in January 2019 and September 2017 respectively.

Description

TactiCath Quartz is a flexible catheter with a deflectable distal section and a contact force sensor at the tip which is indicated for use in cardiac electrophysiological mapping (stimulation and recording) and cardiac ablation to treat supraventricular arrhythmias, including atrial fibrillation. It provides a real‑time measurement of the contact force applied by the catheter tip to a patient's heart wall during an ablation procedure, using white light interferometry. This is designed to give clinicians more control than with a standard catheter by monitoring and modifying the applied force in order to create more effective scar tissue, and prevent accidental damage, during ablation procedures.

TactiCath Quartz is a single‑use device with an overall length of 115 cm. It has a 7 Fr outer diameter and is available with either a 65 mm or 75 mm deflectable distal section. It consists of the following components:

  • A deflectable distal section which includes 4 platinum‑iridium electrodes, a 3.5 mm tip electrode and 3 ring electrodes (spaced 2 mm, 5 mm, 2 mm apart). All of the electrodes can be used for stimulating and recording (for electrophysiological mapping), so a separate cardiac mapping catheter is not needed when using TactiCath Quartz for ablation. The tip electrode also delivers the radiofrequency current to the desired ablation site and is irrigated.

  • A hand‑piece that controls the deflection of the distal section.

  • A thermocouple temperature sensor embedded in the tip electrode.

  • A tri‑axial optical force sensor embedded in the distal section of the catheter. This has a resolution and sensitivity of approximately 1 g and measures the contact force magnitude and orientation every 100 milliseconds.

  • A saline input port with a standard luer fitting at the proximal end of the catheter. This allows the injection of isotonic saline solution to 6 holes located at the tip of the catheter to irrigate and cool the tip electrode and ablation site during the ablation phase of the procedure.

The TactiSys Quartz system connects the radiofrequency generator, the computer with proprietary analysis software (TactiSoft) and the TactiCath Quartz catheter. TactiCath Quartz has separate electrical and optical connectors which plug into the TactiSys Quartz system. Light emitted by the TactiSys Quartz system through the ablation catheter is reflected through cavities in the catheter tip, creating interference between light beams. The pattern of interference changes when contact force is applied by the catheter. These patterns are returned through the catheter and then analysed by the TactiSys Quartz system. The software calculates both the magnitude and orientation of the contact force applied (in a similar manner to Fabry‑Perot interferometry, Liu et al. 2012) and are displayed on a screen.

Additional software from St. Jude Medical is needed for 3D mapping of the signal data. This consists of either:

  • TactiSoft software on a standalone computer and display screen (included in the TactiSys Quartz system), or

  • EnSite contact force module, which integrates the contact force information into the EnSite velocity cardiac mapping system (which includes a display workstation), which may already be in use in a cardiac catheterisation laboratory.

Additional components needed for the ablation procedure include:

  • A compatible radiofrequency generator (only the Ampere generator, St. Jude Medical or the Stockert 70 Generator with software version 1.037, Stockert Medical Solutions are compatible).

  • A compatible irrigation pump and irrigation tubing, such as the Cool Point, irrigation pump (St. Jude Medical) or COOLFLOW pump (Biosense Webster), which connects to the catheter saline port's luer fitting.

  • An introducer sheath with a minimum diameter of 8.5 Fr to insert the catheter into a large central blood vessel, usually the femoral vein. A steerable introducer sheath may be used to aid catheter handling.

  • A separate disposable dispersive pad (indifferent patch electrode) which completes the ablation circuit. This usually connects to the patient's back, but can be placed at other locations to permit maximal skin contact.

TactiCath Quartz is inserted through the introducer sheath and manually moved through the blood vessels in order to map the site of the abnormal heart rhythm. Fluoroscopy and electrocardiograms are used to aid catheter positioning. When the site is identified, the same TactiCath Quartz catheter is used to carry out the ablation and deliver radiofrequency energy (at a recommended contact force of 10 g to 30 g. This blocks the electrical path that causes the abnormal heart rhythm. TactiCath Quartz transmits contact force information (calculated by the TactiSys Quartz system) to the clinician throughout the procedure, using the TactiSoft software on a standalone computer or the EnSite Velocity cardiac mapping system. TactiCath Quartz is also used to confirm entrance and exit block of the electrical impulse (that is successful PVI) during the procedure. The catheter is removed after treatment. In some cases the clinician may prefer to use a separate mapping catheter to identify the site of the abnormal heart rhythm and confirm electrical isolation of the pulmonary veins. A separate mapping catheter can be used simultaneously, sequentially or interchangeably with TactiCath Quartz.

Setting and intended use

TactiCath Quartz would be used in a cardiac catheterisation laboratory during percutaneous PVI. It would be used by cardiac electrophysiologists trained in cardiac ablation who have appropriate training on TactiCath Quartz and the TactiSys Quartz system. The procedure is usually done with the patient under local anaesthesia and sedation, although PVI can also be done under general anaesthesia according to patient or centre preference.

TactiCath Quartz and its additional components are indicated for catheter‑based cardiac ablation when used with a compatible radiofrequency generator, and also for cardiac electrophysiological mapping.

Contraindications for use are similar to other cardiac ablation catheters, and include: cardiac surgery within previous 4 weeks; artificial heart valves; active systemic infection; use in coronary vasculature; myxoma (a heart tumour) or intracardiac thrombus (blood clot); trans‑septal approach in patients with an interatrial baffle or patch; and retrograde trans‑aortic approach in patients with aortic valve replacement.

Current NHS options

NICE guidance on the management of atrial fibrillation recommends offering people a personalised care package of information and prompt referral for specialised management if treatment fails to control symptoms at any stage. Recommended interventions include anticoagulation medications to reduce the risk of stroke, and heart rate and rhythm control (antiarrhythmic) medications or electrical cardioversion. Left atrial catheter ablation is recommended for people with paroxysmal atrial fibrillation, and considered in people with persistent atrial fibrillation, in whom drug treatment has failed to control their symptoms or is unsuitable. NICE interventional procedures guidance on percutaneous radiofrequency ablation states that the evidence for the safety and efficacy of this treatment for atrial fibrillation is adequate to support its use in appropriately selected patients, provided that normal arrangements are in place for audit and clinical governance. The guidance also states that clinicians should ensure that patients fully understand the potential complications, the likelihood of success and the risk of recurrent atrial fibrillation associated with this procedure. The guidance further recommends that the procedure should only be done in specialist units and with arrangements for cardiac surgical support in the event of complications, and should only be done by cardiologists with extensive experience of other types of ablation procedures. Other cardiac ablation procedures are described in related interventional procedures guidance (see relevance to NICE guidance programmes). Other available interventions include surgical lesions (by sternotomy, thoracoscopy or minimally invasive approaches) used alone or in combination with valve or revascularisation surgery to control heart rate.

NICE is aware of the following CE‑marked devices that appear to fulfil a similar function to TactiCath Quartz (and its additional components):

NICE has produced a medtech innovation briefing on the ThermoCool SmartTouch catheter.

Costs and use of the technology

St. Jude Medical has provided the following list prices (excluding VAT) for each component of the TactiCath system:

  • TactiCath Quartz ablation catheter: £3,565

  • TactiSys Quartz system (including TactiSoft software): £25,730

  • EnSite contact force module (which integrates with EnSite Velocity cardiac mapping system which may already be in use in the cardiac catheterisation laboratory): £21,700 

  • Optional steerable introducer sheath: £1,178 to £1,364.

These costs can be reduced for customised NHS contracts depending on volume and contract duration.

A radiofrequency generator (for example the Ampere generator, St. Jude Medical; £31,000), and irrigation pump (for example Cool Point Irrigation Pump, St. Jude Medical; £12,400) are also needed. These components could be used for other ablation procedures and may already be present in some cardiac catheterisation laboratories. A dispersive pad (not supplied by St. Jude Medical) is also needed.

TactiCath Quartz catheters are single‑use and have been validated for a 2‑year shelf‑life. The TactiSys Quartz system has an anticipated lifespan of 7 years and comes with a 12‑month warranty. It requires a force measurement calibration check every 450 days, which would normally be done by St Jude Medical product specialists.

Onsite training in the use of TactiCath Quartz and the TactiSys Quartz system is routinely provided by St. Jude Medical personnel or accredited trainers at no cost.

Likely place in therapy

TactiCath Quartz would be used in people diagnosed with symptomatic atrial fibrillation when drug treatment has failed to control their symptoms (NICE guidance on the management of atrial fibrillation). It would replace conventional radiofrequency ablation catheters without contact force‑sensing technology, which are typically used with a separate mapping catheter. The overall care pathway would not be changed.

Specialist commentator comments

All 4 specialist commentators highlighted that the degree of contact between tissue and catheter is critical for successful pulmonary vein isolation. One specialist commentator noted that real‑time dynamic contact force feedback during cardiac ablation procedures would enable operators to adjust catheter position, improve procedure efficacy and increase safety by avoiding the application of excessive force. One specialist commentator noted that only 1 published study (EFFICAS‑II) has demonstrated that using the device leads to durable lesions by confirming PVI at follow‑up. The study did not define how to achieve lesion durability but suggested a threshold contact force above which better outcomes were obtained. One specialist commentator noted that the consistent message from general published evidence is that contact force‑guided ablation results in better isolation of the pulmonary veins, and improvement in clinical outcomes in addition to other surrogates such as procedure time and radiation dose, when compared with non‑contact force‑guided ablation.

A reduction in fluoroscopy time was highlighted as being important by another specialist commentator given the hazards associated with ionising radiation to both patients and operators.

One specialist commentator highlighted that contact force capability should allow more effective and safer ablation of complex arrhythmia substrates, and should not be restricted to treating atrial fibrillation.

One specialist commentator stated that contact force is 1 of several variables that affect ablation delivery. Cardiac perforation has been shown with force above 40 g; however, energy delivery not only involves contact force but also ablation time and radiofrequency power output. Tissue thicknesses differ between different areas of the atrium and the atrium is surrounded by structures such as the oesophagus posteriorly which may be particularly sensitive to heating. The specialist commentator noted that some data exists that may define efficacy, but none currently exists to define a safe contact force range. Another commentator agreed that what constitutes good contact and sufficient force is less well defined in the literature.

One specialist commentator advised that most centres in which atrial fibrillation ablation is done are within teaching hospitals, and being able to directly observe the force a trainee is exerting (during an ablation procedure) is invaluable but unlikely to be measured in a clinical trial.

The manufacturer states that the patient having had a ventriculotomy or atriotomy within the preceding 4 weeks and the presence of a prosthetic valve are contraindications for using TactiCath Quartz. However, 1 specialist commentator indicated that these patient groups may need ablation treatment for arrhythmias, and that using a contact force‑recording catheter in these patients is advantageous.

One specialist commentator noted that TactiCath Quartz handles less well than they would expect for a catheter used for atrial fibrillation ablation, and stated that they heard the same from other clinicians. The specialist commentator indicated that as a consequence, TactiCath Quartz is frequently used with a steerable introducer sheath (for example Agilis), which incurs an additional cost. The specialist commentator noted that St. Jude Medical is planning to combine the tip technology of TactiCath Quartz with its new catheter platform (Flexibility), which would provide better catheter handling.

Equality considerations

NICE is committed to promoting equality, eliminating unlawful discrimination and fostering good relations between people with particular protected characteristics and others. In producing guidance, NICE aims to comply fully with all legal obligations to:

  • promote race and disability equality and equality of opportunity between men and women

  • eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, marriage and civil partnership, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief (these are protected characteristics under the Equality Act 2010).

The risk of atrial fibrillation increases with age, and is more common in men than women. PVI catheter ablation is typically done under fluoroscopy guidance and therefore not recommended in people who are pregnant. Age, sex and pregnancy are protected characteristics under the Equality Act 2010.