Practice and Safety of Static Balloon Atrial Septostomy Based on a Nationwide Registry Data

Abstract

Background: Balloon atrial septostomy (BAS) is an essential catheterization procedure for congenital heart lesions. Recently, a balloon catheter for static BAS was approved for the first time in Japan as an alternative to the conventional pull-through BAS. Despite the expected increase in the use of static BAS, reports on its safety are scarce worldwide.

Methods and Results: Data on static and pull-through BAS registered in a national registry between 2016 and 2018 were collected. During the study period, 247 sessions of static BAS and 588 sessions of pull-through BAS were performed on a total of 674 patients. Patients who underwent static BAS were older (P<0.001). The incidence of serious adverse events (4.3% vs. 0.9%, P=0.03) and the overall incidence of adverse events (8.1% vs. 3.2%, P=0.03) were higher in static BAS than in pull-through BAS. Among patients who underwent static BAS, the risk factor for adverse events was a body weight <3 kg at the time of the procedure (odds ratio: 4.3 [confidence interval: 1.7–11], P=0.003).

Conclusions: This nationwide study revealed differences in patient background between static and pull-through BAS, as well as a higher incidence of adverse events related to static BAS. Patients weighing <3 kg are at high risk for adverse events after static BAS and may require surgical and circulatory support backup.

Balloon atrial septostomy (BAS) is an essential catheterization procedure for some congenital heart lesions that require interatrial communication, such as to increase cardiac output in right-sided obstructive lesions, to enhance mixing in patients with transposition of the great arteries (TGA), and to relieve left atrial hypertension in left-sided obstructive lesions.

Pull-through BAS, in which the inflated balloon catheter is forcefully pulled through the atrial septum to tear open the atrial septum, is the conventional and standard BAS method.¹ Static BAS (or static balloon atrial septal dilation) using a dilation balloon to enlarge the atrial septal defect is an alternative method, especially when the atrial septum is thickened and resistant to pull-through BAS. Such conditions can be anticipated in infants aged >4–6 weeks or in those with left-sided obstructive lesions such as hypoplastic left heart syndrome (HLHS).^2–5 In addition, all the catheters that could be used for pull-through BAS in Japan required a sheath of 6Fr or larger until recently, which may increase access-related complications in small infants. Therefore, in Japan, static BAS has also been used as an alternative to pull-through BAS to reduce vascular injury in patients with low body weight.

Although static BAS cannot be replaced by surgical atrial septostomy, which is known to have poor results,⁶ and has a certain role in the treatment of congenital heart disease, it has been an off-label procedure in Japan until recently. The TMP PED balloon catheter (Tokai Medical Products, Aichi, Japan) for valvuloplasty, which was specially designed for static BAS, was approved as the first balloon catheter for static BAS in December 2020.⁷ However, the approval of TMP PED was based on few off-label clinical data due to the urgent need caused by the shortage of catheters for pull-through BAS in Japan. Despite the expected increase in the use of static BAS after its approval, reports on its safety are scarce worldwide. The Japanese Society of Congenital Interventional Cardiology (JCIC) has established a registry covering almost all interventional cardiac catheterizations for children with congenital heart disease, which may provide comprehensive nationwide data on the practice and safety of static BAS in Japan.

Therefore, the present study investigated the practice and safety of static BAS in comparison with conventional pull-through BAS, based on the JCIC Registry data.

Methods

Data Source

The JCIC Registry collects data from approximately 100 pediatric and general hospitals performing >4,000 interventional cardiac catheterizations for children and adults with congenital heart disease annually.⁸ Demographics, medical/surgical history, procedural information, and adverse events during hospitalization for all patients undergoing interventional cardiac catheterization are registered at the participating centers in a secure centralized web-based database. Annual audits were conducted to assess data validity and reliability. The participation in the JCIC Registry was approved by the ethics committee of each hospital.

Study Design, Setting, and Participants

This was a multi-institutional retrospective cohort study. Data on static BAS and pull-through BAS registered in the JCIC Registry between 2016 and 2018 were collected, consisting of 247 sessions of static BAS and 588 sessions of pull-through BAS performed on a total of 674 patients. The process from sheath insertion to removal was counted as one session. We compared the: (1) demographics; (2) re-intervention rates; and (3) adverse event rates between the static and pull-through BAS. Demographics and adverse event rates were counted per session, and if both static and pull-through BAS were performed in the same session, they were counted in both the static and pull-through BAS groups. Reintervention rates were calculated for each patient, rather than for each session, and factors associated with adverse events were also investigated in both static and pull-through BAS.

Clinical Data

Anatomical diagnosis was made based on the International Paediatric and Congenital Cardiac Code nomenclature and classified into 5 anatomical groups: (1) left-sided obstructive lesions; (2) right-sided obstructive lesions; (3) TGA; (4) anomalous pulmonary venous return; and (5) others. The severity of heart failure signs and symptoms was graded based on the Modified Ross Heart Failure Classification for Children, and severe heart failure was defined as the Ross Heart Failure Classification III or IV. For pre-procedure risk factors for catheter-related adverse events, we collected information on the presence of duct-dependent circulation, pulmonary hypertension, and dependence on mechanical ventilation, inotropes, mechanical circulatory support, and intra-aortic balloon pumping. The urgency of the procedure was defined as urgent for interventions initiated within 24 h of the decision to treat, emergent for interventions initiated immediately after the decision to treat, and elective for all other scheduled procedures. Procedure time was defined as the time from sheath insertion to removal. The completion of the procedure was defined as whether the balloon was expanded at the atrial septum for static BAS or pulled through the atrial septum for pull-through BAS, regardless of the treatment effect. The severity of catheterization-related adverse events was defined by the change in the patient’s condition and was classified into 5 levels: (1) none; (2) transient/not life-threatening; (3) transient/life-threatening if not treated; (4) life-threatening; and (5) resulting in subsequent death. The third level and above were defined as serious adverse events.

Statistical Analysis

Categorical variables are presented as numbers and percentages and were compared between the groups using Fisher’s exact test. Numerical variables were expressed as mean±standard deviation or median (interquartile range [IQR]) and were compared using the Wilcoxon rank-sum test. For the risk analyses, the patient characteristics and procedure details are listed in Tables 1,2, respectively. Body weight at the time of the procedure was dichotomized into the first quartile (3.0 kg for static BAS and 2.7 kg for pull-through BAS). Statistical significance was set at P<0.05. The analyses were performed using R Studio (version 1.4.1717).

Table 1. Patient Characteristics

	Static BAS (n=247)	Pull-through BAS (n=588)	P value
Age group			<0.001
≤28 days	84 (34)	440 (75)
≥29 days–<1 year	111 (45)	141 (24)
≥1–<3 years	25 (10)	6 (1.0)
≥3–<15 years	25 (10)	1 (0.17)
≥15–<20 years	0 (0)	0 (0)
≥20 years	2 (0.81)	0 (0)
Body weight at the time of procedure, kg	3.7 (3.0–5.7)	3.0 (2.7–3.3)	<0.001
Early delivery (<37 GW)	46 (19)	47 (8.0)	<0.001
Anatomical group			<0.001
Left‐sided obstructive lesions	64 (25.9)	117 (19.9)
Right‐sided obstructive lesions	54 (21.9)	138 (23.5)
Transposition of great arteries	75 (30.4)	310 (52.7)
Anomalous pulmonary venous return	36 (14.6)	7 (1.2)
Others	18 (7.3)	16 (2.7)
Chromosomal abnormalities	14 (5.7)	15 (2.6)	0.04
Genetic syndromes	17 (6.9)	15 (2.6)	0.005
Trisomy 21	1	0
Trisomy 18	3	1
CHARGE syndrome	3	2
Williams syndrome	3	0
Kabuki syndrome	2	3
22q11.2 deletion syndrome	0	1
Jacobsen syndrome	0	1
Other syndromes	5	7
Ross III/IV	118 (47.8)	232 (39.5)	0.050
Oxygen saturation, %	83 (75–90)	81 (75–88)	0.006
Creatinine, mg/dL	0.3 (0.25–0.50)	0.52 (0.35–0.66)	<0.001
Pre-procedural risk factors
Duct-dependent circulations	100 (41)	357 (61)	<0.001
Pulmonary hypertension	90 (36)	236 (40)	0.35
Mechanical ventilation	63 (26)	183 (31)	0.11
Inotropes	27 (11)	97 (17)	0.043
Mechanical circulatory support	5 (2.0)	3 (0.5)	0.053

Data are presented as median (interquartile range [IQR]), n and n (%). BAS, balloon atrial septostomy; GW, gestational week; Ross, modified Ross Heart Failure Classification.

Table 2. Procedure Details

	Static BAS (n=247)	Pull-through BAS (n=588)	P value
Degree of urgency			<0.001
Elective	152 (61)	253 (43)
Urgent	58 (24)	192 (33)
Emergency	37 (15)	143 (24)
Procedure time, min	113 (81–150)	65 (45–100)	<0.001
Fluoroscopy time, min	43 (28–69)	20 (10–34)	<0.001
Combined techniques
None	192 (78)	582 (99)	<0.001
Double balloon	28 (11)	–	–
Trans-septal puncture	25 (10)	4 (0.7)	<0.001
Trans-hepatic puncture	0 (0)	1 (0.17)	1.00
Hybrid surgical approach	3 (1.2)	1 (0.17)	0.08
Concomitant procedures
None	163 (66)	518 (88)	<0.001
Pull-through BAS	49 (20)	–	–
Static BAS	–	49 (8.3)	–
Balloon dilation other than static BAS	–	10 (1.7)	–
Valvuloplasty	4 (1.6)	5 (0.85)	0.46
Stent implantation	2 (0.81)	7 (1.2)	1.00
Stent redilation	29 (12)	1 (0.17)	<0.001
Device closure	0 (0)	2 (0.34)	1.00
Coil embolization	2 (0.81)	0	0.09
Completion of the BAS procedure	243 (98)	584 (99)	0.24

Data are presented as median (interquartile range [IQR]) or n (%).

Results

Patient Characteristics

During the 3-year study period, 247 sessions of static BAS and 588 sessions of pull-through BAS were performed on a total of 674 patients. Patient characteristics counted based on sessions were compared between the static and pull-through BAS groups (Table 1).

Patients who underwent static BAS were older (P<0.001), more likely to have chromosomal abnormalities (P=0.04) and genetic syndromes (P=0.005), were less dependent on inotropes (P=0.043), were more cyanotic (P=0.006), and had lower creatinine levels (P<0.001). The median body weight at the time of the procedure was higher in the static BAS group: 3.7 kg (IQR: 3.0–5.7 kg) than for the pull-through BAS group: 3.0 kg (IQR: 2.7–3.3 kg) (P<0.001). The proportion of low-weight infants <2,500 g at the time of the procedure was similar in both groups (8.9% [static BAS] vs. 10% [pull-through BAS], P=0.41). Early delivery and duct-dependent circulation were more common in patients who underwent static BAS (P<0.001). The anatomical diagnosis differed between static BAS and pull-through BAS groups (P<0.001), and the static BAS group tended to have more left-sided obstructive lesions, such as hypoplastic left heart syndrome, more anomalous pulmonary venous return, and less TGA.

Procedure Details

Table 2 shows details of the procedure for interventional catheterization. The urgency level was higher in the pull-through group, and the pull-through method tended to be chosen in urgent situations. Meanwhile, procedure and fluoroscopy times were longer in the static BAS group (P<0.001). As a combined technique, the double balloon technique was used in 11% of cases of static BAS. In addition, the use of trans-septal puncture was significantly more common in the static BAS group (P<0.001). In the static BAS group, other procedures were performed more commonly in the same session than in the pull-through BAS group (P<0.001). Other procedures performed within the same session included valvuloplasty, stent implantation, stent redilation, coil embolization, and device closure. Both static and pull-through BAS were performed in 49 sessions. The BAS procedure was completed in almost all cases in both groups.

The main devices used in the static BAS group included angioplasty balloons in 140 sessions (56.7%), valvuloplasty balloons in 85 sessions (34.4%), percutaneous transluminal coronary angioplasty balloons in 10 sessions (4.0%), cutting balloons in 5 sessions (2.0%), and other balloons in 9 sessions (3.6%); those for the pull-through BAS group included the Rashkind catheter in 420 sessions (71.4%), the Fogaty catheter in 127 sessions (21.6%), and the Miller catheter in 31 sessions (5.3%).

Re-Intervention Rate

Of the 674 patients identified, 146 received only a static BAS, 486 received only a pull-through BAS, and 42 received both procedures in the initial session. A higher percentage of patients in the initial static BAS group required re-intervention compared to the initial pull-through group (P<0.001); 43 (29.5%) patients in the initial static BAS group, 29 (6.0%) in the initial pull-through BAS group, and 8 (19%) in the initial both-procedures group subsequently required some type of BAS session.

Incidence of Adverse Events

The incidence of serious adverse events (P=0.03) and the overall incidence of adverse events (P=0.03) were higher in the static BAS (Figure 1). Of the 247 sessions of static BAS, in-hospital adverse events were observed in 20 sessions (8.1%), including serious adverse events in 8 sessions (3.2%). Of the 588 sessions of pull-through BAS, adverse events were observed in 25 sessions (4.3%), including serious adverse events in 5 sessions (0.9%). The overall adverse event rate was higher in the static BAS group than in the pull-through BAS group, even after excluding sessions with concomitant procedures (7.4% vs. 3.5%, respectively, P=0.047). The breakdown of adverse events is shown in Figure 2. Adverse events such as tissue injury, arrhythmia, access-related complications, device-related complications, and thromboembolism were observed in both groups. Although there was no statistically significant difference, there was a trend toward more tissue injuries in the static BAS group and more arrhythmias in the pull-through BAS group.

Figure 1.

Adverse event rates for static and pull-through balloon atrial septostomy. The severity of catheterization-related adverse events was defined by the change in the patient’s condition and was classified into 5 levels: (1) none; (2) transient/not life-threatening; (3) transient/life-threatening, if not treated; (4) life-threatening; and (5) resulting in subsequent death. The third level and above were defined as serious adverse events. BAS, balloon atrial septostomy; AEs, adverse events.

Figure 2.

Breakdown of adverse events for static and pull-through balloon atrial septostomy. BAS, balloon atrial septostomy.

Table 3 shows the details of the serious adverse events in both groups. Most patients who had serious adverse events were aged ≤28 days. The techniques used in conjunction with BAS included the hybrid surgical approach in Case 3 and transseptal puncture in Case 6. Concomitant procedures included balloon dilation of the pulmonary vein in Case 7, stent implantation for patent ductus arteriosus and balloon valvuloplasty for the aortic valve in Case 12, and balloon valvuloplasty for the pulmonary valve in Case 13. Adverse events such as shock, arrhythmia, and left atrial perforation were observed in both groups, and the timing of the diagnosis of adverse events was during and after the procedure.

Table 3. Details of Serious Adverse Events

	Age	Weight, kg	Diagnosis	Timing	Adverse events	Additional treatment	Surgical interventions	Subsequent death
Static BAS
1	≤28 days	2.3	SV	During procedure	Sinus bradycardia		+
2	≤28 days	1.8	HLHS	During procedure	VT/VF		+	+
3	≤28 days	2.7	HLHS	During procedure	Shock		+
4	≤28 days	2.3	TGA	During procedure	Shock	Drainage
5	≥1–<3 years	4.5	MS	During procedure	LA perforation		+	+
6	≥29 days–<1 year	3.7	HLHS	After procedure	Thromboembolism
7	≥29 days–<1 year	3.3	TAPVC	After procedure	Cardiac arrest			+
8	≥29 days–<1 year	2.9	TA	After procedure	Others	Foreign body retrieval
Pull-through BAS
9	≤28 days	2.6	TGA	During procedure	Shock
10	≤28 days	2.7	TGA	During procedure	Sinus bradycardia
11	≤28 days	2.9	TGA	During procedure	LA perforation		+
12	≥29 days–<1 year	3.3	AS	After procedure	Progression of TR		+
13	≤28 days	2.8	PAIVS	After procedure	NEC

AS, aortic stenosis; HLHS, hypoplastic left heart syndrome; LA, left atrium; MS, mitral stenosis; NEC, necrotizing enterocolitis; PAIVS, pulmonary atresia with intact ventricular septum; SV, single ventricle; TA, tricuspid atresia; TAPVC, total anomalous pulmonary venous connection; TGA, transposition of great arteries; TR, tricuspid valve regurgitation; VF, ventricular fibrillation; VT, ventricular tachycardia. Other abbreviations as in Table 1.

Unplanned surgical treatment due to adverse events was required in 4 patients in the static BAS group and 2 patients in the pull-through BAS group. There were 3 deaths related to adverse events in the static BAS group. The rate of unplanned surgical intervention or death was significantly higher in the static BAS group than in the pull-through BAS group (2.0% vs. 0.3%, P=0.03).

Risk Factors for Adverse Events

Risk factors for adverse events were investigated, including age, weight at the time of the procedure, anatomical group, presence of any preprocedural risk factors, main device used, and presence of other interventional catheter procedures performed within the same session. Among the patients who underwent static BAS, the risk factors for adverse events were body weight <3 kg at the time of the procedure (odds ratio [OR]: 4.3 [CI: 1.7–11], P=0.003) and a hybrid surgical approach (OR: 24 [CI: 1.2–1470], P=0.018). In contrast, in patients who underwent pull-through BAS, factors other than the pull-through BAS itself, such as the presence of other interventional catheter procedures performed within the same session (OR: 3.1 [CI: 1.04–8.1], P=0.02) and the presence of any combined technique (OR: 12 [CI: 1.04–88], P=0.02), were associated with a higher incidence of adverse events.

Discussion

Recently, a balloon catheter has been approved for insurance coverage for static BAS in Japan; thus, the number of static BAS procedures conducted is expected to increase. This nationwide study showed that static BAS accounted for 30% of the total BAS, even when static BAS was off-label. Although static and pull-through BAS are used in different clinical situations and therefore are associated with different patient demographics, static BAS requires more re-intervention BAS than pull-through BAS. Although the overall incidence of adverse events related to BAS was low, the incidence of serious adverse events and the overall incidence of adverse events were higher in the static BAS group than in the pull-through BAS group. In addition, static BAS tended to be performed on larger patients than pull-through BAS, with only one-quarter of patients weighing <3 kg at the time of static BAS, although the risk of adverse events for those patients was approximately four-fold higher. The effectiveness and safety of the BAS may differ depending on the method used, and care should be taken when selecting the most appropriate method.

In this study, differences in patient and procedural profiles between static and pull-through BAS were identified. As expected, patients who underwent static BAS were older and tended to have left-sided obstructive lesions and thus were at risk of atrial septal thickening, which is the main indication for static BAS. This was also suggested by the higher percentage of patients who underwent simultaneous transseptal punctures. The lower percentage of ductus-dependent circulation and lower creatinine levels in the static BAS group may also be related to older age at the time of the procedure. The proportion of low weight infants (<2,500 g) at the time of the procedure was similar in both groups, and it was unexpected that as many as 10% of patients undergoing pull-through BAS weighed <2,500 g. As it is difficult to place a 6Fr sheath in the femoral vein in patients weighing <2,500 g, we speculate that the procedure was probably performed via the umbilical vein in such cases. The exact reasons for the higher proportion of early delivery, chromosomal abnormalities, genetic syndromes (with no preponderance of specific genetic syndromes), and lower oxygen saturation in the static BAS group are unknown, but a lower proportion of inotropic use may be related to longer procedure time. Because pull-through BAS can be performed in a relatively short period of time, pull-through BAS tends to be the treatment of choice in urgent situations.^9–11 Furthermore, all of these differences may be influenced not only by slight differences in the indications for the procedure, but also by the fact that static BAS was off-label at the time of the study, and pull-through BAS was preferred in situations where both could be performed.

Because BAS is performed for various indications,² it is difficult to define the success or efficacy of BAS in a uniform manner; however, the efficacy has been reported for each anatomical diagnosis. In patients with TGA, a significant increase in oxygen saturation and a high success rate (>95%) in terms of atrial septal defect enlargement have been reported both for static and pull-through BAS.^1,2,11–14 Even in patients with HLHS, a combination of static BAS, pull-through BAS, blade septostomy, and stent placement has been reported to result in successful left atrial decompression in 96% of patients.¹⁵ In the current study, even though the procedure was completed in almost all cases, the proportion of patients who required recurrent BAS was as high as 29.5% in the initial static BAS group, suggesting that the effectiveness of static BAS was much lower than previously reported. Furthermore, surgical intervention was not considered in this study, and the true reintervention rate may have been higher. This is partly because the thickening of the atrial septum, which is resistant to BAS, is a main indication for static BAS. To enhance the effectiveness of BAS in patients with a thickened atrial septum, use of a relatively large balloon (>15 mm),¹³ double balloon technique,⁷ or concomitant use of other procedures, such as atrial septum stenting, blade atrial septostomy, or wire atrial septostomy, may be required to produce effective atrial communication.¹⁶

Pull-through BAS has been reported to cause various complications in its long history, up to 11% of procedures in some series,^17–19 including rhythm disturbances, perforation of the heart, balloon fragment embolization, laceration of atrioventricular valves, systemic or pulmonary veins, and failure of balloon deflation.¹⁷ However, complications associated with pull-through BAS are considered to be very rare these days.²⁰ Regarding complications of static BAS, Thanopoulos et al reported that 23 patients with congenital heart disease or pulmonary hypertension underwent static BAS, and none of them suffered any complications.²¹ In the present study, although serious adverse events of pull-through BAS were indeed very rare (0.9%), serious adverse events associated with static BAS were observed at a much higher rate (3.2%), which included 3 subsequent deaths (1.2% of total static BAS procedures performed). Considering that static BAS tends to be performed in older patients, who are supposed to have a very thick or tough atrial septum, the higher incidence of adverse events related to static BAS likely reflects differences in patient background. However, it remains unclear how the thickness and strength of the atrial septum relate to the high incidence of adverse events when static BAS is used, even though static BAS allows precise control over the rate of balloon inflation and the exact diameter of the opening created with dilation balloons.²² Furthermore, at least 5 of the 8 patients who experienced serious adverse events associated with static BAS had no concomitant procedures or techniques in the same session, suggesting that the influence of concomitant procedures or techniques, such as trans-septal puncture, was minimal. Therefore, the high incidence of adverse events may still be related to the risk of the procedure itself, at least in part, because it requires the appropriate selection of balloon size, guidewire stiffness, and guidewire placement. Now that the balloon for static BAS has been approved, guidance for its widespread use in clinical practice may be needed to standardize the selection of balloon size, guidewire stiffness, and guidewire placement. Furthermore, because of the recent shortage of pull-through catheters, static BAS has been used as an alternative treatment in situations where pull-through BAS cannot be used, but we need to pay attention to the potential difference in the incidence of adverse events.²³

Although risk models for cardiac catheterization based on procedure-type risk categories have been reported, risk factors for adverse events specific to BAS have not been reported.²⁴ This study showed for the first time that those weighing <3 kg have an approximately four-fold risk of adverse events related to static BAS. The hybrid surgical approach, although associated with adverse events related to static BAS, is unlikely to be a major contributor because it was performed in only 3 sessions. Because a higher percentage of patients undergoing static BAS require emergency surgical intervention for adverse events, patients at high risk of adverse events who undergo static BAS may require surgical and circulatory support backup.² It may also be necessary to fully explain the risks to the patient’s family before the procedure and to consider alternative treatments for high-risk patients, such as bilateral PAB combined with surgical atrial septostomy for HLHS.

This study has several limitations. Because this was a retrospective study based on a nationwide registry, only the variables collected by the registry could be used in the analysis. Thus, efficacy could only be assessed by re-intervention rates that did not include surgical interventions or catheterization procedures other than the BAS. Furthermore, assessing the efficacy based on the re-intervention rate would underestimate the effectiveness of BAS if restrictive interatrial communication is intended to promote ventricular growth. In addition, some variables that could affect treatment efficacy (e.g., balloon size, order of procedures within a session, etc.) were not collected. Second, adverse events were reported in conjunction with a sheath-to-sheath catheterization session and not with each procedure in the session; therefore, if procedures other than BAS were performed within the same session, it was not possible to distinguish which procedure caused the adverse events.

Conclusions

This nationwide study revealed differences in patient background between static and pull-through BAS groups, as well as a higher incidence of adverse events in the static BAS group. Patients weighing <3 kg are at high risk for adverse events when undergoing static BAS and may require surgical and circulatory support backup.

Acknowledgments

The views expressed in this article are those of the authors and do not necessarily reflect the official views of the Pharmaceuticals and Medical Devices Agency.

Sources of Funding

This study was supported by a grant from the Japanese Ministry of Health, Labour and Welfare, for the evaluation and development of pediatric medical devices based on real-world clinical data.

Disclosures

All authors declare that they have no conflicts of interest.

IRB Information

The use of the registration data for this study was approved by the Research Ethics Committee of the University of Tokyo (3569).

Data Availability

The deidentified participant data will not be shared.

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