Subcutaneous insertable cardiac monitors (ICMs) continuously record ECG for up to 3 years and are used clinically for the detection of infrequent arrhythmias and atrial fibrillation management. The traditional settings for ICM insertion procedures have been the cardiac catheterization (cath) lab, the electrophysiology (EP) lab and the operating room (OR) - the same facilities used for more complex cardiac device implants, such as pacemakers, cardiac resynchronization therapy devices, and implantable cardioverter defibrillators. This practice became widespread due to the larger size of early ICM models. However, miniaturization of ICM devices has resulted in a less invasive insertion procedure, enabling relocation of device insertion within the hospital to clean rooms, procedure rooms and holding areas, and to practice offices outside the hospital walls [1]. This approach is appealing because it could reduce costs related to the procedure and increase physician and patient convenience and satisfaction [2, 3].

To further evaluate the safety of Reveal LINQ ICM insertion within the hospital, but outside the traditional settings, we built upon previous literature to conduct the first prospective, international multi-site trial to assess the rate of adverse events through 3 months post device insertion. The study was mainly conducted in Europe and collected patient, physician, and detailed staff procedure time interval data to document the resources necessary for the procedure.

The RIO2 International study evaluated the safety of performing Reveal LINQ ICM insertions in-hospital, but outside the traditional procedure settings. It is the first study to characterize resource utilization, procedure time intervals, and physician satisfaction from multiple centers across different geographies, including Europe, Canada and Australia. All 191 insertion attempts were successful, and no untoward events were observed among the 176 patients evaluable for the primary endpoint during a follow-up period of 3 months. Additionally, there was high compliance with the protocol specified insertion procedure. Importantly, even under circumstances with deviations from protocol, there was no increase in the risk of adverse events, punctuating the benign nature of the insertion procedure. As such, these results provide strong evidence that the Reveal LINQ ICM insertion can be safely performed out-of-lab within the hospital by following good sterile technique and the manufacturer’s instructions. Other studies have assessed procedure safety outside the traditional hospital settings. In the randomized Reveal LINQ In-Office 2 (RIO 2) study performed in the United States, low rates of untoward events were observed when device insertion occurred in an office outside the hospital (n = 251; 0.8%) or in the traditional hospital setting (n = 231; 0.9%), with no difference between groups [3]. Two observational studies (performed in Denmark and Australia) compared the safety of ICM insertions performed in a hospital procedure room vs. EP lab and also reported low rates of across insertion environments (0.6–1.7%), with no significant differences between settings [4, 5]. Absent or low complication rates have been observed in three single arm studies in which all device insertions occurred in either a hospital holding area or procedure room (0.0–0.8%) [6‐8]. Importantly, the above findings demonstrate similar or lower complication rates than were observed in a combined analysis of the Reveal LINQ Usability and Reveal LINQ Registry studies (0.7 and 1.6%, respectively), where most device insertions occurred in a cath/EP lab [9]. Finally, a recent analysis of the multi-center Reveal LINQ Registry in a larger population (N = 1222) confirmed these observations, with 0.5% vs 1.0% of complications occurring in patients with procedures performed outside of the EP/cath lab vs in the EP/cath lab, respectively [10]. Together, these findings suggest that insertion of miniaturized ICMs can be moved outside the traditional hospital settings without compromising patient safety.

It is notable that no infections were observed in the present investigation, even under circumstances requiring device repositioning and despite pre-procedure antibiotics only being administered in 44% of patients. This corresponds with previous studies reporting low infection rates across insertion environments regardless of antibiotic use. Specifically, no infections were observed when an ICM was inserted in either the office (n = 251) or traditional hospital setting (n = 231) in the randomized RIO 2 US study. In that investigation, prophylactic antibiotics were administered to approximately 45% of patients, and the rate did not differ between groups [3]. In addition, the Reveal LINQ Registry showed an infection rate of 0.7% among patients who had the procedure performed out-of-lab, and 0.5% for those located in-lab, with similar infection rates observed in patients irrespective of prophylactic antibiotic administration [10]. An interim analysis of the randomized LOOP trial did demonstrate a higher rate of infections following device insertion in a procedure room vs. EP lab (1.6% vs. 0.1%, p = 0.004) despite administration of pre-procedural antibiotics in over 95% of patients [4]. However, the infection rate in the procedure room remained low and comparable to rates observed in-lab in other studies [9, 10]. LOOP also showed a trend for fewer adverse events, including infections, with an increase in physician experience. Lastly, two single arm studies where device insertion occurred in a hospital holding area or procedure room observed infection rates of 0.0 and 0.8% when prophylactic antibiotics were used in none and all insertion procedures, respectively [6, 7]. Together, these data suggest that infection rates with miniaturized ICM insertion are low (≤1.6%) across insertion environments irrespective of antibiotic prophylaxis.

One of the novelties in the present investigation was the characterization of time intervals during the different steps of the patient care pathway across multiple centers and geographies (patient preparation, procedure room occupancy, process time, education, and total visit duration). We observed that device insertion could be completed efficiently out-of-lab with an average visit duration of 115 min, procedure room occupancy time of 54 min, and process duration of 29 min (from patient preparation to skin closure). Others have reported on room occupancy times and have found similar results (55–58 min) [2, 11]. Moreover, in the present study physicians reported few delays over 15 min. This corresponds with findings from the RIO 2 US study, where physicians reported fewer delays when a miniaturized ICM was inserted in an office vs. in-lab [3]. Together, these observations suggest that moving device insertion outside the traditional hospital settings can result in time savings.

Another interesting finding was the involvement of non-physician personnel throughout the care pathway. Although physicians participated in most device insertions, registered nurses and cardiovascular/surgical technologists were predominant in performing pre- and post-insertion activities, respectively. Other single-center studies have also described successful experiences with non-physician providers inserting miniaturized ICMs in ambulatory settings in terms of safety, improved patient flow, reduced costs, and better allocation of resources [6, 11, 12].

Finally, physician perception of performing the procedure outside the traditional settings was very positive in terms of satisfaction with the environment, convenience, and positive feedback from patients. Results from the RIO 2 randomized study, comparing Reveal LINQ insertions performed in-office vs in the traditional hospital settings, also showed improved patient and physician experience with in-office insertions [3].

Findings from the RIO 2 International study, the first prospective, international, multicenter trial of its kind, add to a growing body of evidence that the Reveal LINQ ICM can be safely and efficiently inserted outside the traditional hospital settings.