Low prevalence of significant carotid artery disease on ultrasound in patients proceeding to coronary artery bypass surgery

Should we screen patients for carotid artery disease before lung cancer resection?

Background

Postoperative stroke is a rare complication after lung cancer surgery but has a high mortality rate. No strategy has been recommended to detect carotid artery disease preoperatively in lung cancer patients. The main objective of this study was to evaluate whether a routine carotid duplex ultrasound (DUS) altered the preoperative management of these patients.

Methods

We performed a single-centre, retrospective study of all patients referred for lung cancer resection over a two-year period and reviewed the available carotid DUS results. We quantified the number of carotid artery disease diagnosis, the severity of the disease according to DUS results, and the number of treatments initiated preoperatively. We examined relationships between cardiovascular history and preoperative carotid artery disease diagnosis.

Results

Among the 398 consecutive lung surgery patients, 6% had a preoperative history of stroke or transient ischemic attack, and one developed a postoperative stroke, of cardioembolic origin. Three hundred and seven patients (77%) had preoperative carotid DUS. Carotid DUS results elicited anti-platelet therapy initiation or endarterectomy before lung resection in 7 out of these 307 patients (2.3%). One hundred and seventy-one carotid DUS were retrospectively reviewed by an expert, who diagnosed carotid stenosis >50% and occlusion in 2.3% and 1.2% of patients, respectively. Abnormal carotid DUS was associated with history of lower extremity artery disease (P<0.001), diabetes mellitus (P<0.05) and dyslipidemia (P<0.05).

Conclusions

This retrospective observational study showed that routine preoperative carotid DUS led to few carotid stenosis detection and few perioperative management alterations. Carotid artery disease diagnosis was associated with cardiovascular history and risk factors. Future studies should examine how to select patients who will benefit from a preoperative carotid DUS.

Is carotid screening redundant for patients undergoing coronary artery bypass grafting?

OBJECTIVES

Stroke is a devastating complication following coronary artery bypass grafting, which thankfully occurs with low incidence. The role of preoperative carotid ultrasound remains unclear. Whilst it is a cheap and reliable way of diagnosing carotid stenosis (CS), it is unclear if and how this knowledge should impact on subsequent patient management.

METHODS

A systematic review of the literature was performed using the PRISMA guideline. A literature search was conducted on the MEDLINE database from 1950 to May 2020 using the OVID interface. Fifteen papers out of a total of 5931 were identified for inclusion.

RESULTS

The evidence overall suggests that patients with severe CS are likely to have an increased incidence of postoperative stroke-however, the prevalence of severe CS is low, and even in this cohort of patients, the incidence is not particularly high.

CONCLUSION

In screened patients identified to have severe CS, there appears to be a generally low appetite for undertaking carotid intervention internationally either before or concurrently with the coronary artery bypass grafting. Putting this all together, the widespread screening of asymptomatic patients would appear to not be justified.

Validation of Risk Prediction Models to Detect Asymptomatic Carotid Stenosis

Background Significant asymptomatic carotid stenosis (ACS) is associated with higher risk of strokes. While the prevalence of moderate and severe ACS is low in the general population, prediction models may allow identification of individuals at increased risk, thereby enabling targeted screening. We identified established prediction models for ACS and externally validated them in a large screening population. Methods and Results Prediction models for prevalent cases with ≥50% ACS were identified in a systematic review (975 studies reviewed and 6 prediction models identified [3 for moderate and 3 for severe ACS]) and then validated using data from 596 469 individuals who attended commercial vascular screening clinics in the United States and United Kingdom. We assessed discrimination and calibration. In the validation cohort, 11 178 (1.87%) participants had ≥50% ACS and 2033 (0.34%) had ≥70% ACS. The best model included age, sex, smoking, hypertension, hypercholesterolemia, diabetes mellitus, vascular and cerebrovascular disease, measured blood pressure, and blood lipids. The area under the receiver operating characteristic curve for this model was 0.75 (95% CI, 0.74-0.75) for ≥50% ACS and 0.78 (95% CI, 0.77-0.79) for ≥70% ACS. The prevalence of ≥50% ACS in the highest decile of risk was 6.51%, and 1.42% for ≥70% ACS. Targeted screening of the 10% highest risk identified 35% of cases with ≥50% ACS and 42% of cases with ≥70% ACS. Conclusions Individuals at high risk of significant ACS can be selected reliably using a prediction model. The best-performing prediction models identified over one third of all cases by targeted screening of individuals in the highest decile of risk only.

Does preoperative carotid stenosis screening reduce perioperative stroke in patients undergoing coronary artery bypass grafting?

A number of institutions routinely perform carotid artery ultrasound screening before coronary artery bypass grafting (CABG) to identify carotid artery disease requiring revascularization before or during CABG, with the expectation of reducing perioperative neurologic events. The assumptions are that carotid disease is causally related to perioperative stroke and that prophylactic carotid revascularization decreases the risk of post-CABG neurologic events. Although carotid artery stenosis is a known risk factor for perioperative stroke in patients undergoing CABG, it might be a surrogate marker for diffuse atherosclerotic disease rather than a direct etiologic factor. Moreover, the benefit of prophylactic carotid revascularization in patients with asymptomatic unilateral carotid disease is uncertain. Therefore, we have reviewed the literature for evidence that preoperative carotid artery screening, by identifying patients with significant carotid artery stenosis and altering their management, reduces perioperative neurologic events in those undergoing CABG.