Poor adherence to ultrasound surveillance is associated with infrainguinal bypass graft failure

Abstract

Backgrounds

Infra-inguinal bypass (IIB) surgery is a time-proven and reliable management avenue for the treatment of peripheral arterial disease (PAD). The importance of ultrasound surveillance in maintaining IIB graft patency is well-recognised, yet adherence rates are underreported. This study evaluates the impact of surveillance compliance on graft outcomes in an Australian setting.

Methods

A cross-sectional analysis of IIBs performed between 2010 and 2020 at a major vascular surgical institution in Australia was conducted retrospectively. Demographic data, peri-operative comorbidities and configuration of the bypass were captured as well as post-discharge results. Surveillance compliance was assessed based on adherence to post-operative ultrasound and clinic visits. The chief outcome measure was graft occlusion within 2 years. Secondary outcomes were major amputation, mortality and ambulatory function.

Results

Over a time period of 10 years, 239 bypasses were carried out on 207 individuals. 83% complied with surveillance protocols. Adherence rates were lower in regional patients. Non-compliance was significantly associated with vein graft occlusions (p < 0.01) but not with synthetic grafts. Regional referrals (p < 0.01), low pre-operative haemoglobin (p < 0.01), post-operative transfusion (p = 0.02) and use of prosthetic conduit (p < 0.01) were identified as significant predictors of graft thrombosis. Patients with occluded grafts were at substantially higher risk of ambulatory deterioration (2.4 fold), major limb amputation or death (8.6 fold) within 12 months. One-year survival without amputation was 88.3%.

Conclusion

Enhanced bypass graft surveillance is essential in clinical practice to minimise graft occlusion, reduction in morbidity, limb loss and death. This study reveals suboptimal compliance in Australian vascular surgical setting, particularly in regional areas, underscoring the need for improved education, resource allocation and infrastructural development.

Keywords

Graft surveillance ultrasound bypass australia

Introduction

Chronic limb-threatening ischaemia (CLTI) often originates from Peripheral Arterial Disease (PAD) which is a progressive atherosclerotic process involving the arteries of the lower extremities. It markedly affects older individuals through limb loss and degrades health-related quality of life (QoL).¹ Infra-inguinal bypass (IIB) surgery, despite the advancement of endovascular techniques, continues to be pivotal in CLTI management, demonstrating better outcomes in the long term with regards to limb salvage and mortality.² Australia and New Zealand recorded 5224 IIB procedures from 2018 to 2020.³

Maintenance of patency has been the critical focus in recent vascular literature due to its direct correlation with limb preservation and QoL. Autogenous veins, preferred for IIB grafting, are susceptible to stenosis, which develops in one-third of patients.⁴ This has led to the establishment of routine non-invasive graft surveillance and elective revision strategies to preclude graft occlusion. The 2018 Society of Vascular Surgery guidelines advocate for early post-operative evaluation followed by regular monitoring at 3, 6 and 12 months, and subsequently, at least annually.⁵

Duplex Ultrasound Scanning (DUS), providing detailed anatomical and haemodynamic insights, remains the cornerstone of graft surveillance. Its efficacy in early lesion detection, coupled with timely interventions, mitigates the risk of graft failure and limb amputation.⁶ The cost-effectiveness of DUS surveillance, in stark contrast to the expenses incurred from graft thrombosis and limb loss, further underscores its imperative role in post-operative management.^7,8

Despite the extensive study of ultrasound graft surveillance, actual adherence rates remain underreported, with most efficacy studies excluding non-participatory patients.⁶ This study evaluates the impact of surveillance compliance on graft outcomes in an Australian public hospital setting, with a primary focus on adherence to post-operative ultrasound and clinic visits. We hypothesise that non-adherence to ultrasound graft surveillance is associated with worse graft patency, graft thrombosis and limb loss. By scrutinising graft patency, limb salvage, and mortality, our research aims to underscore the pivotal role of DUS in IIB surgical outcomes, seeking to identify and modify factors to enhance patient outcomes.

Methods

Study population and design

From 1^st January 2010 to 1^st January 2020, IIB grafts in individuals afflicted by CLTI and lifestyle-limiting intermittent claudication (IC) were studied retrospectively at a centre in Melbourne, Victoria, Australia. The St Vincent’s Hospital Melbourne Human Research Ethics Committee granted ethics approval. The indications of aneurysmal disease, acute limb ischaemia, resection of malignancy and trauma were criteria of exclusion.

The ANZSVS oversees the Australasian Vascular Audit (AVA) database where data is proactively recorded. The AVA, together with the hospital’s electronic medical records (EMR) and International Classification of Diseases (ICD-10) codes allowed for a thorough inclusion of cases.³

Information was collected on medical backgrounds, demographics, pre-surgery assessments, characteristics of grafts, pathological findings, complications, monitoring and subsequent interventions of grafts, mobility status, ipsilateral major limb amputations, hospital stay duration, destination upon discharge and mortality rates at 30 days and 1 year. Specifically, we used the Modified Monash Model (MMM) to classify regional and rural areas based on patients’ primary residence addresses.⁹ Any residence located in MM2 or above was categorised as regional or rural.

Details of patient characteristics comprised age, gender, referral sources, cardiovascular risk factors, medications, pre-operative investigations and post-operative red cell transfusion requirement (reference range for Haemoglobin level: 125–185 g/L in men, 115–165 g/L in women). Bypass specifics were collated, including indication, urgency, operation type, prior bypass, anaesthesia type, graft inflow, outflow and number of run-off vessels, conduit type and quality. Details for data collection are outlined in Supporting Document 1.

Ultrasound surveillance compliance

We evaluated the influence of adherence to a surveillance program with ultrasound on graft failure. A patient was deemed compliant with surveillance if they attended a minimum of one follow-up ultrasound and clinic appointment at 6 weeks. The next intervals were at 6 months, 1 year and 2 years. Missing any of these would result in non-compliance. Unplanned admissions due to graft pathologies in the setting of non-compliance were also captured.

For 2 years, we recorded details of ultrasound surveillance and sorted the findings into three categories: patent, at-risk and occluded grafts. A graft was considered at-risk if it showed critical stenosis, evidenced by a peak systolic velocity (PSV) exceeding 300 cm/s or a velocity ratio (Vr) above 3.5; alternatively, an at-risk graft might exhibit a low mean graft velocity (MGV) below 45 cm/s or a decline in the ankle-brachial index greater than 0.15, indicating potential issues with inflow, outflow or the graft conduit itself.¹⁰

Outcome measures

The main outcome measured was the occlusion of the primary graft within a 2-year timeframe, not counting the failures of the graft within 30 days. The condition of the graft was verified using ultrasound, CT angiography or during surgery. Secondary endpoints included the 1-year rates of ipsilateral major amputation, death, ambulatory capability and residential status to assess the impact of graft occlusion. Mobility levels were classified as independent, requiring a walking aid or confined to a wheelchair; meanwhile, the discharge locations were noted as either home, nursing home or a rehabilitation centre.

A graft considered primarily patent is one that has remained open continuously without needing any intervention, aside from addressing diseases more proximal or distal to the graft, excluding the conduit and anastomoses themselves. The determination of patency rates was based on the timing and results of surveillance ultrasounds, as well as the specifics of any procedures from re-interventions noted during hospital stays within the 2-year observation period.¹

Statistical analysis

Descriptive statistics and correlation analyses were employed to examine the interactions among variables. For variables with small sample sizes, Fisher’s exact test was applied, while the chi-square test was utilised for examining relationships between categorical variables. To construct a predictive model and assess the impact of variables on graft failure and functional outcomes, multivariate regression, univariate Cox proportional hazards regression and Kaplan–Meier plots were utilised. Predictor variables for the final model were chosen based on p-values below 0.25. Non-adherence to ultrasound surveillance protocols was analysed as a time-varying covariate within a longitudinal framework, aggregated by each participant. The assumption of hazard proportionality was verified using the Schoenfeld residuals test. A significance threshold of 5% was established, and STATA 15.0 was the statistical software employed. The selection of statistical methods was carefully done to prevent overfitting of the model.

Results

Over a decade, 239 IIB surgeries were conducted on 207 individuals. Follow-up was incomplete for 64 cases, with 41 (17.2%) not adhering to surveillance and 23 (9.6%) lost due to either death or palliation. In 19 (8.0%) instances, acute graft failure was noted, including 7 cases of surveillance non-compliance. The patency rates at 2 years stood at: primary patency at 66.9%, primary-assisted patency at 82.9% and secondary patency at 89.7%. A year into the study, 19.3% of participants experienced a decline in mobility, while the amputation-free survival rate was 88.3%.

Study population characteristics

The average age was 67.6 +/− 11.5 (range, 35–91), with a majority being male (80.8%). The prevalence of cardiovascular risk factors was high, with 74.9% having a history of smoking and 82.0% presenting with severe systemic diseases. Most subjects were receiving antiplatelet (86.6%) and lipid-lowering treatments (87.2%). IIB surgery was primarily performed for tissue loss (48.1%), followed by lifestyle-limiting intermittent claudication (IC) (30.5%) and rest pain (21.3%), with 51.5% undergoing elective procedures, predominantly under general anaesthesia (69.0%). The common femoral artery was the most frequent site for graft inflow (67.0%), and the popliteal artery for outflow (66.5%), with single-vessel run-off in 38.9% of cases. The most frequently used conduit was the single-segment great saphenous vein (GSV) in a reversed configuration (54.39%), with PTFE grafts used in 15.1% of cases. The quality of autologous conduits was deemed good in 84.7% of instances. The average pre-operative haemoglobin level was 128.9 +/− 21.2(g/L), with 39.3% requiring post-operative transfusion.

The average hospital stay was 18.7 +/− 15.2 days (range, 4–94), with a 30-day mortality rate of 2.1%. Post-operatively, nearly 30% of patients went through rehabilitation, with 76.2% returning home. Prior to surgery, 70.0% of patients were mobilising independently, a figure that slightly decreased to 64.7% at the 1-year mark. The percentage of patients using a wheelchair increased from 1.4% pre-surgery to 10.0% one year later. At the one-year follow-up, 23 major limb amputations had occurred [Tables 1–4].

Table 1.

Characteristics of study population and investigation results.

Demographics	N	%
Gender, male	193	80.75
Age, mean (SD, range)	67.6 (11.5, 35–91)
Referral source, regional	156	65.27
Insurance status, public	237	99.16
Co-morbidities
IHD	131	54.81
Diabetes	104	43.51
Hypertension	209	87.45
Smoking history
- Non-smoker	60	25.10
- Ex-smoker	128	53.56
- Current	51	21.34
Creatinine >150 mmol/L	35	14.64
ASA status
- ASA II	43	17.99
- ASA III	180	75.31
- ASA IV	16	6.69
Medications
Antiplatelet therapy
- No	32	13.39
- Single agent	177	74.06
- DAPT	30	12.55
Anticoagulation	76	31.80
Beta-blocker use	78	36.97
Statin use	184	87.20
Best medical therapy*	131	61.21
Pre-operative blood tests	Mean+/−SD	Range
Haemoglobin (g/L)	128.90+/−21.23	67–169
Haematocrit (l/l)	0.392+/−0.61	0.20–0.50
Creatinine concentration (umol/L)	103.26+/−78.70	34–720
Albumin (g/L)	34.23+/−5.18	18–45
HbA1c if diabetic (%)	7.35+/−1.88	5–13
Pre-operative workup	N	%
TTE
- Normal TTE	117	55.45
- Abnormal TTE	34	16.11
- No TTE	60	28.44
RFT
- Normal RFT	55	26.07
- Abnormal RFT	44	20.85
- No RFT	112	53.08
Functional Cardiac tests
- Normal findings	55	26.07
- Abnormal findings	40	18.96
- No test	116	54.98
Pre-op PCI if abnormal functional cardiac test	19	47.50

Values are given as mean +/− standard deviation(SD) and range, or number(N) and percentages(%).

*Best medical therapy encompasses smoking cessation, antiplatelet and statin therapy.

Table 2.

IIB surgery context and graft characteristics.

Bypass context	Total, N (%)	Patent graft, N	Occluded graft, N
Indication of bypass
- Tissue loss (ulcer or gangrene)	115 (48.12)	91	24
- Severe IC	73 (30.54)	61	12
- Rest pain	51 (21.34)	40	11
Urgency
- Elective	123 (51.46)	104	19
- Semi-urgent	104 (43.51)	80	24
- Emergency	12 (5.02)	8	4
Operation type
- Bypass graft	170 (71.13)	135	35
- Bypass + endarterectomy	58 (24.27)	49	9
- Bypass + thrombectomy	10 (4.18)	7	3
- Interposition	1 (0.42)	1	0
Completion angiogram	63 (26.36)	49	14
Prior bypass	70 (29.29)	52	18
Re-do bypass	44 (18.41)	31	13
Anaesthetic choice
- General	165 (69.04)	131	34
- Regional	66 (27.62)	53	13
- GA + RA	8 (3.35)	8	0
Bypass characteristics
Inflow
- CFA	160 (66.95)	158	26
- SFA	49 (20.50)	35	14
- AK popliteal	9 (3.77)	9	0
- BK popliteal	15 (6.28)	10	5
- Profunda femoris	6 (2.51)	4	2
Outflow
- AK pop	82 (34.31)	74	8
- BK pop	77 (32.22)	59	18
- Crural vessel	70 (29.29)	55	15
- Pedal vessel	10 (4.18)	4	6
Number of run-off vessels
- 1	93 (38.91)	69	24
- 2	75 (31.38)	65	10
- 3	71 (29.71)	58	13
Conduit
- GSV, reversed	130 (54.39)	113	17
- PTFE	36 (15.06)	21	15
- GSV, non-reversed	27 (11.30)	24	3
- Arm vein	16 (6.69)	13	3
- GSV, in situ	12 (5.02)	10	2
- PTFE with cuff	8 (3.35)	4	4
- Composite vein	6 (2.51)	4	2
- SFV	2 (0.84)	2	0
- Omniflow	1 (0.42)	0	1
- SSV	1 (0.42)	1	0
Conduit quality
- Good	172 (84.73)	149	23
- Suboptimal	31 (15.27)	23	8
Complications
Infection	13 (5.44)	6	7
Haematoma	8 (3.35)	7	1
Cardiac	4 (1.67)	4	0
Wound breakdown	3 (1.26)	2	1
Lymph leak	3 (1.26)	1	2
Respiratory	2 (0.84)	2	0
Multi-organ dysfunction	1 (0.42)	1	0
Gastrointestinal	1 (0.42)	1	0
Renal	1 (0.42)	1	0
Death within 30 days	5 (2.09)	4	1
Post-operative transfusion requirement	83 (39.34)	58	25

Values are given as number (N) and percentages (%) of patients.

Table 3.

Discharge destination.

	Mean +/− SD	Range
Length-of-stay	18.72+/−15.23	4–94
Discharge outcomes	N	%
- Home	144	68.25
- Rehabilitation	62	29.38
- Nursing home	1	0.47
- Death	4	1.9
Post-rehabilitation outcomes
- Home	48	76.19
- Other	12	19.05
- Death	3	4.76

Values are given as mean +/− standard deviation (SD) and range, or number (N) and percentages (%) of patients.

Table 4.

Pre- and post-operative mobility status.

Status	Pre-operative, N (%)	Post-operative, N (%)	At 1 year, N (%)
Independent	146 (69.86)	92 (44.44)	123 (64.74)
Gait aid	60 (28.71)	105 (50.72)	48 (25.26)
Wheelchair	3 (1.44)	10 (4.83)	19 (10)

Values are given as number (N) and percentages (%) of patients.

Predictors of Primary Graft Occlusion

Throughout the 2-year monitoring period, we noted 47 instances of graft occlusions. Key factors significantly associated with the occlusion of grafts encompassed:

• Non-adherence to scheduled ultrasound surveillance (p < 0.01)

• Referrals from regional areas (p < 0.01)

• Statin therapy (p = 0.03)

• Reduced levels of haemoglobin before surgery (p < 0.01)

• The necessity for blood transfusions after surgery (p = 0.02)

• Prosthetic conduit (p < 0.01)

Kaplan–Meier survival curves for these predictors are presented in Figures 1–5.

Figure 1.

Kaplan–Meier survival curve by ultrasound surveillance compliance.

Figure 2.

Kaplan–Meier survival curve by referral source.

Figure 3.

Kaplan–Meier survival curve by statin use.

Figure 4.

Kaplan–Meier survival curve by post-operative transfusion requirement.

Figure 5.

Kaplan–Meier survival curve by conduit type.

Our analysis revealed a notable difference in ultrasound surveillance compliance based on geographic region, with metropolitan areas showing higher compliance (90.3%) compared to regional areas (79.9%). However, the disparity in compliance rates between regions did not reach statistical significance.

In the subset of 180 vein grafts, 84.4% were compliant with post-operative ultrasound surveillance. Notably, of the 28 non-compliant vein grafts, six grafts were incidentally captured, with four found to be occluded at presentation and two remaining patent. There was a statistically significant association between non-compliance and vein graft occlusion (p < 0.01).

Among the 59 patients with synthetic grafts, 78.0% were compliant. In the non-compliant group, three of the 13 grafts were occluded at presentation, while one was patent. No statistically significant association was found between non-compliance and synthetic graft occlusion.

Predictors of graft surveillance non-adherence

We conducted additional analyses to investigate the factors impacting graft surveillance adherence. Both geographical location and ASA status were found to have statistically significant effects on compliance.

Patients residing in regional areas (MM2 and above) were significantly less likely to comply with follow-up surveillance compared to those in metropolitan areas, with an odds ratio (OR) of 0.39 (p = 0.046). This suggests that patients in regional areas had approximately 61.2% lower odds of complying with surveillance.

Worse ASA status was also associated with lower surveillance compliance. Patients with ASA status three had 87.7% lower odds of compliance (OR = 0.12, p = 0.043), and those with ASA status four had 94.9% lower odds of compliance (OR = 0.05, p = 0.013) compared to ASA status 2. This reflects a strong inverse relationship between ASA status and adherence.

Predictors of functional outcomes

Graft failure significantly correlated with mobility deterioration (2.4 times higher risk, p < 0.01), and an increase in major limb amputation and mortality within 1 year (8.6 fold, p < 0.01). No demonstratable association was observed between graft failure and discharge destination. [Table 5]

Table 5.

Graft failure and functional outcomes.

Functional outcomes at 1 year	Patent graft, N (%)	Occluded graft, N (%)	p
Deterioration in mobility status	20 (14.93)	15 (35.71)	<0.01
Major limb amputation or death	6 (3.95)	16 (34.04)	<0.01

Values are given as number (N) and percentages (%) of patients.

Discussion

This study represents one of the first to report on real-world infra-inguinal bypass graft surveillance in public hospital settings in Australia.¹¹ Existing literature consistently highlights the cost-effectiveness of graft surveillance, particularly for vein grafts, by preventing graft thrombosis and limb loss through early detection and timely intervention.^7,8 Despite its proven benefits, our findings revealed a suboptimal adherence rate of 83%, with non-adherence being more prevalent among patients residing in regional and rural areas. This is concerning given the established role of surveillance in improving patient outcomes.

Our analysis demonstrated that poor adherence to surveillance is significantly associated with vein graft occlusion. However, maintaining graft patency requires more than surveillance alone. A holistic approach is necessary, which includes managing factors such as peri-operative anaemia, medications and conduit selection. Patients with occluded bypass grafts were at a substantially higher risk of experiencing ambulatory deterioration, major amputation or death. These findings underscore the critical importance of preserving graft patency to achieve favourable patient-centred outcomes.

Geographical location emerged as a notable factor contributing to non-adherence, with patients in regional and rural areas showing significantly lower compliance rates compared to those in metropolitan regions. This may be attributed to several barriers, including limited access to specialised vascular imaging providers, longer travel distances and fewer healthcare resources.¹² Additionally, the absence of a centralised imaging provider in Victoria likely exacerbated these challenges, creating delays in timely scanning and further reducing the likelihood of adherence to surveillance protocols. These findings suggest that addressing geographical disparities in healthcare access is vital for improving graft surveillance outcomes.

In addition to geographical location, patients with worse ASA status (ASA three and 4) were significantly less likely to attend follow-up surveillance. This highlights the role that comorbidity burden plays in adherence to graft surveillance, with sicker patients potentially facing more barriers to consistent follow-up.

In our study, ultrasound surveillance of prosthetic grafts did not demonstrate a significant improvement in graft patency, which is consistent with observations from other studies. Despite this, many clinicians continue to perform surveillance on prosthetic grafts in real-world practice, possibly due to a belief in its utility for detecting issues that clinical examination might miss. It may be that clinical examination is more effective for these types of grafts, or perhaps alternative imaging modalities need to be explored. As noted in the ESVS guidelines, surveillance strategies should be tailored to individual patient risk profiles, potentially incorporating other imaging techniques where necessary.¹³

Limitations

Our study has certain limitations that must be considered. Due to its retrospective nature, loss to follow-up may have affected the analysis, particularly in drawing associations between surveillance non-adherence and graft patency. Additionally, other factors that could contribute to non-adherence, such as the patient’s primary language, socioeconomic status and regional differences in ultrasound interpretation, were not included in our analysis. The variability in ultrasound interpretation, especially in regional centres lacking specialised personnel, may also have impacted the reliability of the surveillance data. A prospective cohort study with a standardised surveillance protocol and a unified vascular imaging provider could help address these gaps and better assess whether improving adherence enhances graft patency and increases the rate of prophylactic interventions.

Additionally, our study did not collect data on post-operative compliance with antiplatelet therapy, statin therapy or smoking cessation. While these factors are known to influence graft patency, they were beyond the primary focus of our study, which was centred on ultrasound surveillance compliance. The absence of this information limits our ability to fully assess their impact on graft survival in our cohort. Future prospective studies should include detailed monitoring of post-operative medication adherence and lifestyle modifications to provide a more comprehensive understanding of factors affecting graft patency.

As part of our study, we assessed ambulatory deterioration and major limb amputation as functional outcomes related to graft preservation and failure. Our intent was to capture the broader clinical relevance of graft surveillance and the cascading effects of graft failure on patient quality of life. However, we acknowledge that this approach does not fully encompass the patient’s overall quality of life. Future prospective studies should employ multidimensional measurement tools, such as the Short Form Health Survey and the EuroQol-5 Dimension forms, to provide a more comprehensive assessment of the functional impacts of bypass graft failure.¹³

Future practice recommendations

We recommend the implementation of a comprehensive registry that consolidates graft surveillance data across health networks.^3,14 While the AVA database captures intra-operative details and early post-operative outcomes, it lacks data on pre-operative investigation, surveillance, patency, amputation and functional outcomes following discharge.^2,3 Expanding the AVA to include this information, along with facilitating entries from multiple users (for instance, sonographers), would provide a more complete picture of patient outcomes and allow for better tracking of long-term graft performance. In addition, addressing resource disparities in regional areas is critical. Initiatives such as a vascular sonographer outreach program could help bridge the gap in access to imaging services, while educating both patients and healthcare professionals, particularly general practitioners in regional areas, about the importance of graft surveillance in prolonging graft patency and improving limb salvage rates. Surveillance responsibilities could also be shared with local GPs, allowing them to conduct routine ultrasound surveillance and clinical assessments to reduce the burden on centralised facilities.

Lastly, developing a unified platform imaging referrals and reviews in Victoria could significantly improve coordination and standardisation of graft surveillance. A centralised referral system, led by vascular units, could prioritise high-risk grafts and ensure timely interventions based on graft anatomy and scan urgency. Future research should adopt a multicentric approach, employing standardised surveillance protocols to investigate factors specific to the local population that affect IIB outcomes and improve post-surgical success rates across Australia.

Conclusion

Our research offered a perspective on the monitoring and results of IIB grafts within the current context of vascular surgery in Australia. Our study highlights the indispensable role of effective ultrasound surveillance in managing IIB grafts. The insights gained point towards the need for improved educational initiatives, resource allocation, and infrastructure development to enhance patient outcomes in IIB surgeries.

Footnotes

Author contributions

Mei Ping Melody Koo – conceptualisation, data curation, investigation, methodology, project administration, resources, validation, visualisation, writing - original draft, review and editing of drafts.

Hansraj Riteesh Bookun – conceptualisation, data curation, formal analysis, methodology, supervision, writing - review and editing drafts.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Mei Ping Melody Koo

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Poor adherence to ultrasound surveillance is associated with infrainguinal bypass graft failure – An ongoing challenge in Australia

Abstract

Backgrounds

Methods

Results

Conclusion

Keywords

Introduction

Methods

Study population and design

Ultrasound surveillance compliance

Outcome measures

Statistical analysis

Results

Study population characteristics

Predictors of Primary Graft Occlusion

Predictors of graft surveillance non-adherence

Predictors of functional outcomes

Discussion

Limitations

Future practice recommendations

Conclusion

Footnotes

Author contributions

Declaration of conflicting interests

Funding

ORCID iD

References