Evidence review

Clinical and technical evidence

Regulatory bodies

A search of the Medicines and Healthcare Products Regulatory Agency website revealed no manufacturer Field Safety Notices or Medical Device Alerts for TactiCath Quartz.

A search of the US Food and Drug Administration database: Manufacturer and User Device Facility Experience (MAUDE) for 'TactiCath' between 2009 and 2015 identified 106 records, each describing the use of TactiCath Quartz (or its predecessor technology, TactiCath) in cardiac ablation procedures (but not explicitly for atrial fibrillation). Reported events occurred after October 2014, with the most recent in October 2015. Reported events included injury (96), death (7) and malfunction (2), with event type for 1 record not reported.

Common issues reported:

  • Known risks associated with the procedure (91 records) including pericardial effusion, cardiac perforation, tamponade, pericarditis, atrial‑oesophageal fistula, cerebrovascular events, steam pop and death.

  • Product defects (13 records), including short circuits caused by fluid leaks, loss of contact force‑sensing, deflection issues, no flow through the catheter and device error message.

  • Incorrect usage (2 records), specifically excessive force and accessing the left side of the heart in a retrograde fashion.

The manufacturer has stated that design and process changes have since been incorporated in the manufacture of TactiCath Quartz.

The MAUDE database houses reports on medical devices that were submitted because of suspected device‑associated deaths, serious injuries and malfunctions. Reports are submitted by mandatory reporters such as manufacturers, importers and facilities where the devices are used and voluntary reporters such as health care professionals, patients and consumers.

It should be noted that the MAUDE database is a passive surveillance system and potentially includes incomplete, inaccurate, untimely, unverified or biased data. The incidence of an event cannot be determined from this reporting system alone due to potential under‑reporting of events and lack of information about frequency of device used.

Clinical evidence

A systematic literature search identified 7 studies that reported on the TactiCath ablation catheter (the predecessor to TactiCath Quartz) for radiofrequency ablation in patients with atrial fibrillation. This included 1 multicentre randomised controlled trial (Reddy et al. 2015), 1 non‑randomised comparative study (Wakili et al. 2014), 1 non‑randomised comparative study that used retrospective data from a local registry (Wutzler et al. 2014), and 3 prospective single‑arm multicentre interventional studies (Kautzner et al. 2015, Kuck et al. 2012, Reddy et al. 2012). The remaining study was a prospective, single‑arm, single‑centre interventional study (Vaccari et al. 2014). This has not been included in this briefing because it was considered to provide lower quality evidence.

The TOCCASTAR randomised controlled trial (Reddy et al. 2015) was done across 17 global study centres and enrolled 317 patients. It was powered to assess the non‑inferiority of a contact‑sensing catheter (TactiCath, intervention arm; final group size n=155) compared with a standard ablation catheter (ThermoCool, control arm; final group size n=145). Different navigation systems were used in the 2 arms (EnSite NavX in the TactiCath arm and CARTO in the control arm). The primary outcome was a combination of short‑term ablation success (complete isolation of all pulmonary veins), longer‑term effectiveness (prevention of symptomatic arrhythmia without drugs) and safety (device‑related serious adverse events). Long‑term ablation success (at 12 months) was achieved in 67.8% of patients with TactiCath and 69.4% of patients with ThermoCool (p<0.05 for non‑inferiority, 15% margin allowed for effectiveness). Device‑related serious adverse events were seen in 1.97% of patients with TactiCath and 1.40% patients with ThermoCool (p<0.05 for non‑inferiority, 9% margin allowed for safety). The authors concluded that TactiCath met the safety and effectiveness end points. The authors also reported that the contact force achieved by operators using TactiCath was highly variable, and that only 33% (12/36) of the operators achieved optimal contact force (where 90% or more of the lesions in a single patient were created using a contact force of 10 g or more). However, through retrospective threshold analysis, the authors were able to confirm that optimal contact force, achievable by using TactiCath, improved effectiveness outcomes. An overview and summary of the results can be found in tables 1 and 2 of the appendix.

A non‑randomised single‑centre study in Germany (Wakili et al. 2014) compared ablation using a contact force‑sensing catheter (TactiCath, n=32) with ablation using a standard ablation catheter (ThermoCool, n=35) and analysed procedural parameters and clinical outcomes. A separate circular catheter was used for mapping in both arms. The study found that compared with a standard ablation catheter, contact force‑guided ablation resulted in fewer energy applications needed to isolate the pulmonary vein (34 compared with 44, p<0.05), greater reduction in impedance in the first 10 seconds (9.09 ohm compared with 6.58 ohm, p<0.001), shorter left atrial procedure time (78 minutes compared with 96 minutes, p<0.05), and shorter fluoroscopy time (33 minutes compared with 51 minutes, p<0.001). Freedom from atrial fibrillation was not statistically significantly different between the groups; 62.5% compared with 62.9% (at 6 months) and 59.4% compared with 62.9% (at 12 months) for contact force‑sensing and standard ablation catheters respectively. Similar complication rates were seen in both groups, but none was considered to be severe. An overview and summary of the results can be found in tables 3 and 4 of the appendix.

A single‑centre comparator study in Germany (Wutzler et al. 2014) retrospectively analysed data from a local atrial fibrillation ablation registry, in order to determine if atrial fibrillation recurrence rate differed in PVI ablation procedures done with contact force‑sensing catheters (TactiCath, n=31) and non‑contact force‑sensing catheters (control group, CoolPath, n=112). Both arms used the same navigation system (EnSite NavX). A separate circular mapping catheter was used in both arms to confirm pulmonary vein isolation after the ablation. The authors reported that at 12‑month follow‑up atrial fibrillation had recurred in 36.6% (41/112) of patients with CoolPath and 16.1% (5/31) of patients with TactiCath p (p=0.031). Additionally, the total procedure time was significantly shorter in the TactiCath group (128 minutes) compared with the CoolPath group (158 minutes, p=0.001). No other significant differences in ablation time, total ablation energy or fluoroscopy time were reported between the groups. One minor complication was reported in the TactiCath group, and 1 major and 3 minor complications were reported in the CoolPath group (in the absence of contact force measurement). An overview and summary of the results can be found in tables 5 and 6 of the appendix.

Three prospective, single‑arm, multicentre studies described the use of TactiCath in patients with paroxysmal atrial fibrillation (Kautzner et al. 2015, Kuck et al. 2012, Reddy et al. 2012). A total of 58 patients were included in these studies (with 2 studies reporting outcomes on the same patients). The TOCCATA study (Kuck et al. 2012) reported serious adverse events in 12% (4/34) of patients (including tamponade, sinus bradycardia, groin bleeding and stroke), with audible steam pops reported in 12% (4/34) of patients. At 3 months after the procedure, mild pulmonary vein stenosis was reported in 12% (4/34) of patients. At 12 months after the procedure, 26% (9/34) of patients experienced serious adverse events related to arrhythmia recurrence. The study by Reddy et al. (2012) included the same paroxysmal atrial fibrillation subgroup as the TOCCATA study. Of the 32 patients followed up until the end of the study, 17 were categorised as having a successful initial ablation procedure. In the 10 patients with an average contact force greater than 20 g recorded during the ablation procedure, 80% (8/10) had no atrial fibrillation recurrence or atrial fibrillation recurrence with confirmed durable PVI. However, all 5 patients having ablation with an average contact force of less than 10 g experienced atrial fibrillation recurrence at 12 months. The EFFICAS‑II study (Kautzner et al. 2015) reported durable PVI at 3 months in 85% of cases (77/91 pulmonary veins from 24 patients), compared with 72% (73/103 pulmonary veins from 26 patients) in the earlier EFFICAS‑I study (p=0.037). This study also used a separate circular catheter to confirm PVI isolation after the ablation. Two patients (8.3%) experienced tamponade related to the procedure using TactiCath; 1 patient needed pericardiocentesis and the other needed surgery despite the site of perforation not being identified. A summary of results can be found in table 7 of the appendix.

Recent and ongoing studies

One ongoing trial on TactiCath was identified in the preparation of this briefing:

  • TactiCath contact force ablation catheter study for atrial fibrillation post approval study (TactiCathPAS) – This is a prospective, multicentre, interventional study to collect confirmatory evidence on the safety and effectiveness of TactiCath Quartz for treating symptomatic paroxysmal atrial fibrillation using contact force‑assisted irrigated radiofrequency ablation. The expected primary completion date for the study is stated as July 2016, but according to St. Jude Medical the primary completion date is February 2017.

Costs and resource consequences

TactiCath Quartz would replace conventional catheters without contact force‑sensing technology used in radiofrequency ablation for atrial fibrillation. Conventional radiofrequency ablation catheters without contact force‑sensing technology are available from St. Jude Medical, ranging in cost from £1,147 to £3,255. Separate circular mapping catheters (to confirm electrical PVI) are also available from St. Jude Medical, ranging in cost from £1,550 to £2,170.

When compared with standard ablation catheters, using TactiCath Quartz and the additional components needed (the TactiSys Quartz system and additional software either integrated or non‑integrated into a dedicated workstation) would pose an additional expense to the NHS. However, this could be offset if the device is associated with a long‑term reduction in atrial fibrillation recurrence (fewer healthcare visits, reduced medications), reduction in procedure and fluoroscopy time, and reduced complications.

No published evidence on resource consequences was identified.

Strengths and limitations of the evidence

The evidence to support the use of TactiCath Quartz in managing atrial fibrillation is limited in terms of quantity, with only 2 prospective (Reddy et al. 2015, Wakili et al. 2014) and 1 retrospective (Wutzler et al. 2014) comparative trials being identified. The TOCCASTAR study by Reddy et al. (2015) was the only randomised controlled trial and the largest study reviewed. It compared the TactiCath contact force‑sensing catheter with a non‑contact force‑sensing catheter (ThermoCool) in patients with symptomatic paroxysmal atrial fibrillation. This study was statistically powered to show non‑inferiority of TactiCath and included various definitions of procedural success in order to compare outcomes with previously published studies. The authors did not provide information about why a non‑inferiority trial was selected rather than a superiority trial. A superiority trial could have demonstrated improved efficacy or safety for TactiCath. This was a multicentre study (17 centres), and the variations between the study centres (for example treatment differences) was accounted for using multivariate analysis. The authors acknowledged several limitations and potential sources of bias in the study, including: the lack of strict contact force guidelines in the TactiCath (intervention) group in the study protocol; the high variability in contact force measurements achieved by operators (not accounted for in the multivariate analysis); and that the use of 2 ablation catheters from 2 different manufacturers needed 2 different mapping systems (with the operators having less experience with 1 of the systems). The authors accepted that the small differences in outcomes may have been attributable to the different ablation catheter designs. This study did not include a UK centre and was highly selective in its recruitment of patients so it is not clear how generalisable it is to UK practice.

Both studies by Wutzler et al. (2014) and Wakili et al. (2014) evaluated ablation procedures done with and without contact force‑sensing catheters, allowing the potential benefits of contact force to be compared with standard practice in a population with atrial fibrillation. The study by Wakili et al. (2014) was prospective but not randomised, with the standard catheter (ThermoCool) being used in the first 35 consecutive patients and TactiCath being used in the next 32 consecutive patients, which introduces the potential for selection bias. The study by Wutzler et al. (2014) retrospectively analysed observational data from a local atrial fibrillation registry and had the potential for selection bias and confounding. Although Wutzler et al. (2014) and Wakili et al. (2014) reported that using a contact force‑sensing catheter reduced total procedural time, as well as left atrial procedure time and fluoroscopy time respectively, it is unclear whether these reductions were clinically important. Furthermore, both studies reported no statistically significant difference in ablation time between groups. Both studies also had the potential for reporting bias. Major limitations of both studies include the use of multiple models of catheters (ThermoCool in the Wakili et al. [2014] study, and CoolPath in the Wutzler et al. [2014] study) in the intervention and control arms, and the use of different mapping systems between arms (in the Wakili et al. [2014] study), making it difficult to attribute outcomes to the TactiCath catheter alone.