Let’s be CLEAR: Cath Lab Evaluation of Atherosclerotic Risk is a disease modifying opportunity

Coronary artery disease (CAD) remains a leading cause of morbidity and mortality globally, with early identification and management of risk factors being crucial to its management. Patients undergoing day-case angiograms represent a relatively high-risk population, yet often lack comprehensive risk-factor evaluation. Interventions have been shown to be more consistently aligned with guideline-recommended targets when conducted in hospital. As such, the cardiac catheterisation lab offers an invaluable opportunity for cardiovascular risk factor screening and intervention.

We enrolled 585 consecutive patients attending our institution for day-case coronary angiograms. Blood samples were collected for lipid profile and glycated haemoglobin (HbA1c), in addition to blood pressure recordings and a smoking history taken. The results were available for clinician review on the day, with encouragement to intervene on off-target risk factors.

We identified high levels of patients with established CAD and risk factors outside of the target range. This included 77% and 70% with low-density lipoprotein (LDL) and non-high-density lipoprotein (non-HDL) above target, respectively. There were also 19% smoking and 14% with HbA1c above target. A number of patients with CAD and previously undiagnosed risk factors were also identified, including 18 newly diagnosed with diabetes. A considerable proportion of these had interventions made on the day of their procedure.

Our results demonstrate a clear benefit to risk-factor screening in the catheterisation lab, with a high number of patients found to have risk factors outside of the target range, or previously undiagnosed, and appropriate interventions were made as a result.

Introduction

Coronary artery disease (CAD) remains one of the leading causes of mortality worldwide,¹ accounting for nine million deaths globally in 2021.² Numerous modifiable risk factors are associated with its development and progression, including dyslipidaemia, glycaemic control and smoking.^3–9 Effective management of risk factors can reduce or even reverse the disease process.^10–15

Screening for risk factors, however, is often sporadic and opportunistic in nature. Indeed, even after they are identified, gaps in treatment are common, with patients frequently falling short of updated guideline targets.^16-20 It has been shown that when risk factors are identified, interventions are more consistently aligned with guideline targets when conducted in hospital by a specialist service, than in primary care.^21–24

This is particularly relevant for patients presenting to the cardiac catheterisation lab, who are known to have an increased prevalence of both atherosclerosis and uncontrolled cardiovascular risk factors.^25–27 Despite this, routine risk factor screening and management in such patients is not widespread.²⁸ This is reflected in the Society for Cardiovascular Angiography and Interventions (SCAI) expert consensus on best practice, which recommends pre-procedural bloodwork, but stops short of recommending assessment of lipids and other risk factors.²⁹ This practice has come under scrutiny in the literature in recent years, with calls for a greater onus to be placed on routine risk factor assessment and management in the catheterisation lab setting.²⁸

We believe the identification of patients with suboptimal control of modifiable CAD risk factors in the catheterisation lab provides an invaluable opportunity for disease modification. Our aim was, therefore, to identify uncontrolled CAD risk factors in such patients, and to intervene, as appropriate, to reach recommended guideline targets.

Method

The Catheterisation Laboratory Evaluation of Atherosclerosis Risk factors (CLEAR) study was a single-centre, open-label, prospective cohort study designed to identify and address modifiable CAD risk factors in patients presenting for day-case angiography.

We prospectively enrolled 585 consecutive patients attending our institution for day-case invasive coronary angiography over a two-year period, spanning 2020–2022.

Once informed consent was obtained, a full risk factor profile for each patient was collected. This included age, sex, lipid profile, diabetes status, smoking status and blood pressure. Medication regimen was also recorded for each patient, as well as any adjustments made. Blood pressure readings were taken at the time of patient arrival and again prior to discharge. Blood samples including lipid profile and glycated haemoglobin (HbA1c) were collected during pre-assessment, with the results being available for clinician review on the day of the procedure.

Angiographic results were combined with European Society of Cardiology (ESC) guidelines to identify patients not reaching risk factor targets. Targets for those with CAD were low-density lipoprotein (LDL) <1.4 mmol/L, non-high-density lipoprotein (non-HDL) <2.2 mmol/L, HbA1c <53 mmol/L and not actively smoking. Choice of medication and the dosing used were at the clinician’s discretion. Interventions made in patients currently smoking consisted of smoking cessation advice, as well as referral to a local smoking cessation service, where the patient was agreeable. Data regarding patient risk factors and interventions made were recorded and analysed using SPSS version 28.

Results

In total, 585 patients were enrolled in the study. Male patients accounted for 63% of participants. Patient age ranged from 31 to 87 years, with a mean age of 63.2 years. Prior percutaneous coronary intervention (PCI) had been performed in 16.9% of patients. In total, 497 (85%) were found to have CAD, which included everything from minor plaque burden to severely stenotic disease.

Of these, 77% (383) had a LDL above target (≥1.4 mmol/L). This was in addition to 70% (348) who had a non-HDL above target (≥2.2 mmol/L). The glycaemic target for patients with diabetes and CAD (<53 mmol/L) was not being achieved in 14% of patients. A further 19% of patients with CAD were active smokers (figure 1).

Off-target LDL was addressed in 54% (205/383) of patients with CAD. This compared with 56% (198/352) of those above non-HDL target range. Smoking cessation intervention was conducted in 44% (42/96) of smokers. Medication adjustments were made in 31% (22/70) of patients whose HbA1c was above target (figure 2).

There was an increase in the frequency with which risk factor interventions were being made over time. The 383 patients with CAD and a LDL above target were chronologically divided into the first 191 enrolled and the second 192. Adjustments to lipid-lowering therapy were made in 49% (93/191) of the first half, rising to 58% (112/192) in the second half of the study. A similar trend was identified in patients outside of non-HDL targets, with 51% (89 of 176) of patients intervened upon in the first half of the study, rising to 62% (109 of 176) in the second half. A comparable pattern was seen in patients with CAD and diabetes who were outside their target glycaemic range. This comprised of 5% (3 of 55) with interventions made in the first half of the study, rising to 15% (8 of 55) in the second.

A further 18 patients with CAD (4%) who were not previously known to be diabetic, were found to have HbA1c levels within the diabetic range (≥48 mmol/L), with 16 of these (89%) commenced on a hypoglycaemic agent on the day and referred on to diabetology.

Discussion

Our results demonstrate a clear benefit in screening for modifiable CAD risk factors in patients attending for day-case angiography. We observed high levels of patients with CAD and risk factors outside of ESC guideline targets. We also identified a number of patients with previously undiagnosed risk factors. It is known that if interventions are not made in the hospital setting at the time of diagnosis, they are less likely to be aligned with guideline targets.^21–24 As such, this programme provided an invaluable opportunity to intervene more effectively against atherosclerosis.

The greatest scope for benefit was in lipid management. High levels of patients with CAD had LDL and non-HDL levels above target, with the majority of these having adjustments made to their lipid-lowering therapy, consisting of statin initiation or uptitration. It is worth noting that even though a patient’s lipid target may have changed in light of their angiogram results, 19% and 27% of those enrolled were found to have a LDL and non-HDL, respectively, which would have been outside of target, regardless of their angiographic findings (LDL ≥3.0 mmol/L, non-HDL ≥3.4 mmol/L).

There was also a sizeable cohort of patients with a HbA1c level above target, including 18 patients who were newly diagnosed with diabetes. Many of these had interventions made on the day of the procedure. A further 19% of patients with CAD were actively smoking, with just under half of these having a formal intervention made. While other CAD risk factors were recorded as part of the study, these were somewhat less helpful in the overall analysis. Individual blood pressure readings, for example, may be overinterpreted in the peri-procedural setting, owing to both ‘white-coat’ hypertension and procedural sedation.

There were notably increasing rates of risk factor interventions being made over the course of the study. This is felt to reflect increasing awareness and pro-activeness of staff towards addressing risk factors on the day of the procedure. It also demonstrates how a programme of this type can alter clinician behaviour over time. This was evident in both lipid-lowering management and glycaemic control.

Lower absolute rates of intervention

Explanations for the relatively low rates of intervention seen, include a high throughput of patients with the associated workload placed on staff, as well as a period of time required to raise staff awareness and change practice. Regarding glycaemic management, there was a degree of reluctance among cardiology physicians to initiate new agents prior to diabetology assessment. Given the potential for harm associated with initiating certain drugs without appropriate expertise, as well as concern regarding metformin use post-contrast, in many cases this may have been appropriate. The COVID-19 pandemic, which began shortly after commencement of the study, undoubtedly also impacted on routine clinical practice. The primary barrier to increasing the rate of smoking intervention was patient willingness.

Representative cohort

The cohort included in the CLEAR study were felt to be representative of a typical catheterisation lab cohort, with outcomes of angiography reflecting current best practice guidelines. The majority (73%) were treated with optimal medical therapy in the first instance. PCI was performed in 8% of patients, with a further 19% going on to be discussed at a HEART team meeting.

Study limitations

The CLEAR study was a single-centre design and it is uncertain the extent to which these results would be reflected in other centres. In addition, there was no standardised protocol in the study governing risk factor interventions, and, as such, there was an inevitable degree of variation in practice between clinicians. This, however, is likely in keeping with real-world variations in practice.

Conclusion

The CLEAR study illustrates a distinct benefit to screening for modifiable CAD risk factors in the catheterisation lab. While there have been calls for this in the literature of late,²⁸ it is often deferred to the primary care and outpatient settings. By conducting such screening at the time of angiography, we were able to institute earlier interventions and provide patients with a greater chance of minimising atherosclerosis progression.

Key messages

• Patients presenting for day-case angiography have high levels of uncontrolled cardiovascular risk factors, which are frequently not at guideline targets
• Risk factor screening in this setting allows for earlier and more targeted intervention
• Numerous patients with previously undiagnosed risk factors were also identified
• This programme changed clinical practice over time with increasing rates of risk factor interventions seen

Conflicts of interest

None declared.

Funding

None.

Study approval

The authors have obtained informed consent from each patient participating in the study for participation and subsequent publication of the data arising from same, in line with local and international ethical best practice.

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