Patient‐reported quality of life and acceptance of the extravascular implantable cardioverter‐defibrillator: Results from pivotal study

The pivotal study of the extravascular implantable cardioverter‐defibrillator (EV ICD) recently demonstrated primary efficacy and safety endpoints comparable to previous ICD systems. Patient experience with this novel device has not been reported. The current study examined the standardized patient‐reported outcome (PRO) metrics of quality of life (QOL) and patient acceptance of the device.

device acceptance, extravascular ICD, patient reported outcomes, quality of life

| INTRODUCTION
Cardiac electrophysiology research has established the efficacy of the implantable cardioverter-defibrillator (ICD) to reduce mortality and has consistently innovated the technology to improve the ICD patient experience. 1 ICDs have rapidly evolved from transvenous ICDs (TV-ICD) to subcutaneous ICDs (S-ICD) and more recently, the extravascular ICD (EV ICD) with substernal lead placement. 2The need for continuous surveillance and the impact of lead-related complications have adversely impacted the patient experience and prompted development of alternative, nontransvenous ICD systems.
The EV ICD has potential patient benefits that include nontransvenous leads, smaller device size (33 cm 3 ) than S-ICD (60 cm 3 ), greater battery longevity than other nontransvenous platforms, and the capability of pacing and antitachycardia pacing.The small size of the pulse generator and its placement at the midaxillary line, coupled with substernal lead placement may significantly impact the patient experience with ICD therapy.The EV ICD was recently evaluated in a global clinical study and demonstrated primary efficacy and safety endpoints and freedom from major complications comparable to previous ICD systems. 3Successful medical innovation must include attention to quality of life (QOL) and patient acceptance to create true benefit and broad utility.This initial study included metrics to address the patient experience and acceptability of the EV ICD.
This study aims to report on the QOL and acceptance of the EV ICD by patients enrolled in the EV ICD Pivotal Study from baseline to 6-month follow-up and to compare standardized patient-reported outcome (PRO) metrics in patients with the EV ICD to patients with TV-ICD and S-ICDs using historical norms. 4

| Study design
The EV ICD Pivotal Study, described previously, 3,5 was a prospective, single-arm, nonrandomized, global, premarket approval study.Patients were requested to complete the 12-Item Short Form Survey (SF-12) 6 physical and mental health QOL surveys at baseline before implant and at 6 months following implant.SF-12 scores range from 0 to 100, with higher scores indicating better PROs for physical and mental health status.Additionally, patients who completed the informed written consent forms in English could complete the Florida Patient Acceptance Survey (FPAS) 7 QOL survey at 6 months.
Overall and component FPAS scores also range from 0 to 100.Better patient acceptance is associated with higher overall and component scores for return to function and positive appraisal and lower component scores for device-related distress and body image concerns.Patients with a prior device implanted were excluded from the analysis.Stratifications by age, sex, body mass index (BMI), and atrial fibrillation (AF) used baseline data.
Additionally, a retrospective comparison to historical data from a previous study 4 that included FPAS survey results for patients with S-ICD and TV-ICD systems was performed by extracting data points from the published dot plots.

| Statistics
Changes from baseline SF-12 components were evaluated using the paired t test.The associations of baseline characteristics with results at 6 months were assessed individually using a two-sample t test with an assumption of equal variance (two groups) or a one-way analysis of variance (three groups).Dunnett's t test was used to compare FPAS scores for EV ICD with historical norms for S-ICD and TV ICD.
No other adjustment for multiple comparisons or multiple tests was used.

| Institutional review board approval
The study protocol was approved by ethics committees at participating sites and all patients provided written informed consent.

| RESULTS
Of patients who successfully received a device (n = 299), 281 did not have a previous device implanted.Of those, 247 completed both the baseline and 6-month SF-12 QOL surveys (average age 53.7 ± 13.3 years old, 27.1% female, and 81.8% primary prevention).Among patients who completed the informed consent in English (n = 119), 109 completed the FPAS survey (average age 52.6 ± 13.7 years old, 32.1% female, 77.1% primary prevention).Full patient baseline characteristics are listed in Table 1.

| SF-12 scores
The physical SF-12 score (indicative of PRO for physical health) for the EV ICD increased for patients from baseline to 6 months (45.4 ± 9.4 vs. 46.8± 9.1 respectively, p = .020,Figure 1).No statistically significant difference was observed in the mental SF-12 score in EV ICD patients (indicative of PRO for mental health) from baseline to 6 months (49.3 ± 10.4 vs. 50.5 ± 9.7, p = .061,Figure 1).When the 6-month SF-12 scores were stratified by sex (Supporting Information S1: Table 1 history of AF (Supporting Information S1: Table 2), and whether the patient experienced a shock (Supporting Information S1: Table 3), no statistically significant difference in either physical or mental score was observed.Additionally, no statistically significant difference was observed in physical score by BMI (Supporting Information S1: Table 4).

| DISCUSSION
As follow-up to the EV ICD pivotal study main results, 3 this paper reports on the patient experience with this novel device.We hypothesized that EV ICD's smaller device footprint and its imperceptible substernal lead positioning might be better tolerated by patients than transvenous or SICDs.We found a small but statistically significant improvement in component scores for physical QOL and no changes in mental QOL in baseline to 6 months comparisons.No differences were noted by sex, history of AF, or the experience of ICD shock.Age-related differences were found, such that physical QOL was highest in the youngest age groups (<50-yearold) and mental health scores were the lowest in the same group, consistent with previous research. 8Patient acceptance scores of the EV ICD patients were statistically significantly better than those reported by S-ICD and TV-ICD patients using historical norms. 4bscale comparisons indicated that EV ICD patients reported less device-related distress and less body image concerns than patients with S-ICD and TV-ICDs.Moreover, the EV ICD patients reported more positive appraisal of the ICD than TV-ICD patients.
These results suggest that the EV ICD fosters device acceptance.
However, the results should be interpreted cautiously as the sample is based on the initial group of patients who were willing to accept a novel technology.These patients may differ from those who declined or were ineligible for study.Specifically, positive congruence or positive bias is possible, in which patients align their beliefs with their positive decision.Since the patients agreed to "accept" or implant this device, they align their beliefs with high acceptance. 9Patients recruited at high profile centers may also have a greater sense of trust in their attending medical team and improve their tendency toward acceptance. 10Regardless, patients in this initial study appeared to accept the novel procedure of the EV ICD with lead positioning under the sternum, to potentially gain the advantages of a smaller device silhouette, availability of pacing therapies, and anatomically unobtrusive implant site.Future randomized controlled trials will have to further examine the trade-off beliefs that may underlie these positive patient appraisals.
Medical innovation without attention to QOL and patient acceptance can create technology with limited benefits and use. 11e current study employed both a general QOL measure (SF-12) and a device-specific QOL measure (FPAS) and both provided useful sensitivity to a physical health change over time and device acceptance information.Rapid innovations and investigations over the past four decades have transformed ICD therapy from a simple decision set to a multi-device choice with broad sets of attributes to engage in a shared decision-making process. 12Sampling the patient experience with attention to both general QOL and disease-and device-specific patient experience metrics can allow for increased understanding for potential targets for intervention.4][15] Comprehensive measurement of health, disease management, and general and diseasespecific QOL remain essential to evaluate new technologies.

| LIMITATIONS
This study had several limitations to consider when interpreting the results.First, only patients from the EV ICD Pivotal study that completed the QOL surveys were included in this study, with a minority of patients completing the FPAS questionaries due to the requirement of the informed consent being completed in English.
Second, the comparison of FPAS scores between patients in the EV ICD Pivotal study and the previously reported FPAS values for the TV-ICD and S-ICD was a retrospective analysis of data extracted from a study that was not a randomized clinical trial and is therefore limited.Patientreported outcomes represent a broad set of potentially important variables to continue to examine, and this study provided a preliminary look at two key variables.Additional research examining shock anxiety, body image, and activity levels will add to our understanding of the patient experience.The small sample of a selected group of potential ICD patients also limits our ability to generalize this data.Longer followup, beyond 6 months, will also allow for a more complete picture of the patient experience in future studies.

| CONCLUSION
The EV ICD Pivotal Study met the prespecified safety and efficacy endpoints, and the current paper expanded on our understanding of patient experience with the EV ICD by examining QOL and patient acceptance of this novel device.We found that patients with the EV ICD reported statistically significant improvements in physical QOL and no changes in mental QOL from baseline to 6-month comparisons.No differences were noted by sex, history of AF, or the experience of ICD shock.Younger patients (<50-year-old) reported better physical QOL and worse mental QOL at each timepoint.EV ICD patients reported better total patient acceptance than TV-ICD or S-ICD patients using historical norms of the metrics.These results suggest that the initial EV ICD patients had less device-related distress and better overall acceptance of their ICD, suggesting that the EV ICD is evaluated positively by patients.
SEARS ET AL.

F
I G U R E 1 SF-12 quality of life survey responses.Average survey response scores for patient reported mental (red line) and physical (blue line) SF-12 quality of life surveys are shown at baseline and 6 months.Error bars represent the 95% confidence interval.T A B L E 2 FPAS score by device.EV ICD (N = 109) S-ICD (N = 101) EV-vs.S-ICD TV ICD (N = 100) EV-vs.

Table 4 )
, with patients with a lower BMI showing a lower mental score on average.T A B L E 1 (Continued)cardiac implantable device) for the EV ICD (80.4 ± 15.7) was higher than that previously reported for the S-ICD (70.2 ± 17.8, p < .0001)orTV-ICD(73.0 ± 17.4, p = .004)(FPASScoreresultsinTable2).Devicerelated distress was reported to be significantly less for the EV ICD (20.0 ± 19.8) compared to those previously reported for the S-ICD (36.5 ± 29.4, p < .0001)andTV-ICD(29.0 ± 23.7, p = .017).Positive the S-ICD (27.7 ± 32.5, p = .001)andtheTV-ICD(21.6 ± 25.6, p = .12).When the EV ICD overall and component FPAS scores were stratified by sex (Supporting Information S1: Table6), and whether the patient experienced shock (Supporting Information S1: Table7), no differences were observed.When stratified by history of AF, the Positive Appraisal score was higher in patients without AF compared patients with AF (85.7 ± 17.7 vs. 71.3±42.2,respectively,p= .037;SupportingInformationS1:Table8)while all other component scores and the overall score were not significantly different by the presence or absence of AF (Supporting Information S1: Table8).Finally, when stratified by either BMI or age, statistically significant differences in Body Image Concern were observed (BMI ≥ 25: 11.5 ± 20.0 vs. BMI < a For this component of the FPAS a lower score is associated with better patient acceptance.to