Low Toe–Brachial Index Is Associated With Stroke Outcome Despite Normal Ankle–Brachial Index

Introduction: We investigated whether the toe–brachial index (TBI) is associated with stroke prognosis and evaluated this association in patients with normal ankle–brachial index (ABI).Methods: Acute ischemic stroke patients who underwent TBI measurements were enrolled. Poor functional outcome was defined as modified Rankin Scale score ≥3. Major adverse cardiovascular event (MACE) was defined as stroke recurrence, myocardial infarction, or death. Normal ABI was defined as 0.9 ≤ ABI ≤ 1.4.Results: A total of 1,697 patients were enrolled and followed up for a median 39.7 (interquartile range, 25.7–54.6) months. During the period, 305 patients suffered MACE (18.0%), including 171 (10.1%) stroke recurrences. TBI was associated with hypertension, diabetes, atrial fibrillation, aortic plaque score, ABI, and brachial–ankle pulse wave velocity (all p < 0.05). In multivariable logistic regression, TBI was inversely associated with poor functional outcome in all patients [odds ratio (OR) 0.294, 95% confidence interval (CI) 0.114–0.759], even in patients with normal ABI (OR 0.293, 95% CI 0.095–0.906). In multivariable Cox regression, TBI < 0.6 was associated with stroke recurrence [hazard ratio (HR) 1.651, 95% CI 1.135–2.400], all-cause mortality (HR 2.105, 95% CI 1.343–3.298), and MACE (HR 1.838, 95% CI 1.396–2.419) in all patients. TBI < 0.6 was also associated with stroke recurrence (HR 1.681, 95% CI 1.080–2.618), all-cause mortality (HR 2.075, 95% CI 1.180–3.651), and MACE (HR 1.619, 95% CI 1.149–2.281) in patients with normal ABI.Conclusions: Low TBI is independently associated with poor short- and long-term outcomes in acute ischemic stroke patients despite normal ABI.

Toe pressure and toe brachial index are predictive of cardiovascular mortality regardless of the most diseased arterial segment in symptomatic lower-extremity artery disease—A retrospective cohort study

Objective Although lower extremity arterial disease (LEAD) is most often multisegmental, the predominant disease location and risk factors differ between patients. Ankle-brachial index (ABI), toe-brachial index (TBI), and toe pressure (TP) are predictive of outcome in LEAD patients. Previously, we reported a classification method defining the most diseased arterial segment (MDAS); crural (CR), femoropopliteal (FP), or aortoiliac (AOI). Current study aimed to analyze the associations between MDAS, peripheral pressure measurements and cardiovascular mortality. Materials and methods We reviewed retrospectively 729 consecutive LEAD patients (Rutherford 2–6) who underwent digital subtraction angiography between January, 2009 to August, 2011 and had standardized peripheral pressure measurements. Results In Cox Regression analyses, cardiovascular mortality was associated with MDAS and non-invasive pressure indices as follows; MDAS AOI, TP <30 mmHg (HR 3.00, 95% CI 1.13–7.99); MDAS FP, TP <30 mmHg (HR 2.31, 95% CI 1.36–3.94), TBI <0.25 (HR 3.20, 95% CI 1.34–7.63), ABI <0.25 (HR 5.45, 95% CI 1.56–19.0) and ≥1.30 (HR 6.71, 95% CI 1.89–23.8), and MDAS CR, TP <30 mmHg (HR 4.26, 95% CI 2.19–8.27), TBI <0.25 (HR 7.71, 95% CI 1.86–32.9), and ABI <0.25 (HR 2.59, 95% CI 1.15–5.85). Conclusions Symptomatic LEAD appears to be multisegmental with severe infrapopliteal involvement. Because of this, TP and TBI are strongly predictive of cardiovascular mortality and they should be routinely measured despite the predominant disease location or clinical presentation.

Toe-brachial index is beyond a peripheral issue in patients with type 2 diabetes

Background Atherosclerosis is the leading cause of death in patients with diabetes. We aimed to evaluate the association between ankle-brachial index (ABI) and toe-brachial index (TBI) with carotid intima-media thickness (CIMT) in patients with type 2 diabetes (T2DM). Methods This cross sectional study included 296 patients with T2DM who met the American Diabetes Association criteria for the assessment of peripheral arterial atherosclerosis. The ABI ≤ 0.9 and TBI ≤ 0.7 were considered as abnormal values. Linear and logistic regression analyses were performed to evaluate the association between TBI/ABI and CIMT. Results Right CIMT was significantly greater in the low TBI group (p = 0.03) while, left CIMT did not show a significant difference. Each 0.1-unit decrease in TBI value was independently associated with 0.017 mm increase in the right CIMT (β ± SE; -0.017 ± 0.005, p = 0.002) and with odds of the presence of increased CIMT [odds ratio and 95% confidence interval: 1.21 (1.02, 1.44)] after adjustment with all traditional risk factors. There was not any significant association between ABI and increased CIMT. Conclusions Beyond a suitable tool for the diagnosis of peripheral artery disease in patients with T2DM, TBI can be applied for prediction of subclinical carotid atherosclerosis.

Ankle and Toe Brachial Index Extraction from Clinical Reports For Peripheral Artery Disease Identification: Unlocking Clinical Data through Novel Methods

ABSTRACT Importance: Despite its high prevalence and poor outcomes, research on peripheral artery disease (PAD) remains limited due to the poor accuracy of billing codes for identifying PAD in health systems. Objective: Design a natural language processing (NLP) system that can extract ankle brachial index (ABI) and toe brachial index (TBI) values and evaluate the performance of extracted ABI/TBI values to identify patients with PAD in the Veterans Health Administration (VHA). Design, Setting, Participants: From a corpus of 392,244 ABI test reports at 94 VHA facilities during 2015-2017, we selected a random sample of 800 documents for NLP development. Using machine learning, we designed the NLP system to extract ABI and TBI values and laterality (right or left). Performance was optimized through sequential iterations of 10-fold cross validation and error analysis on 3 sets of 200 documents each, and tested on a final, independent set of 200 documents. Performance of NLP-extracted ABI and TBI values to identify PAD in a random sample of Veterans undergoing ABI testing was compared to structured chart review. Exposure: ABI <0.9, or TBI <0.7 in either right or left limb used to define PAD at the patient-level Main Outcome: Precision (or positive predictive value), recall (or sensitivity), F-1 measure (overall measure of accuracy, defined as harmonic mean of precision and recall) Results: The NLP system had an overall precision of 0.85, recall of 0.93 and F1-measure of 0.89. The F-1 measure was similar for both ABI and TBI (0.88 to 0.91). Recall was higher for ABI (0.95 to 0.97) while precision was higher for TBI (0.94 to 0.95). Among 261 patients with ABI testing (49% with PAD), the NLP system was able to extract ABI and TBI values in 238 (91.2%) patients. The NLP system had a positive predictive value of 92.3%, sensitivity of 89.3% and specificity of 92.3% to identify PAD. Conclusion: We have successfully developed and validated an NLP system to extract ABI and TBI values which can be used to accurately identify PAD within the VHA. Our findings have broad implications for PAD research and quality improvement efforts in large health systems.

Mönckeberg’s Disease of the Lower Limb

Vascular calcification represents a group of several pathological states of differing aetiologies. Mönckeberg medial sclerosis is considered to be more widespread in the lower abdominal region and lower limbs. We present a 59-years-old male patient presented right foot gangrene. At physical exploration, femoral and popliteal pulses were presented and the ankle-brachial pressure index was 0.45, and the toe-brachial index was 0.33. The patient underwent distal angioplasty of anterior and posterior tibial arteries and due to inaccurate evolution a transmetatarsal amputation was required. Mönckeberg’s medial sclerosis is diagnosed with an ABI>1.1, however, questions have been raised about the validity and the role of ABI in diagnosis of Mönckeberg’s medial sclerosis. Colour-doppler vascular ultrasound allow a non-invasive technique widely available to detect vascular calcification and to differentiation between Mönckeberg’s medial sclerosis and the atherosclerosis-related lesions.

Isolated low toe–brachial index is associated with increased mortality and morbidity: a retrospective cohort study

Objective: The aim was to assess the prognostic impact of perfusion assessments including ankle–brachial Index (ABI) and toe–brachial Index (TBI) on survival of patients who present with diabetic foot ulceration and to analyse clinical outcomes when patients are categorised into three levels of limb ischaemia. Method: This was a retrospective cohort analysis of consecutive patients presenting with foot ulceration. Patients continued with their standard of care, after having baseline assessments of limb perfusion. Patients were retrospectively categorised into three groups according to baseline ABI and TBI: Group 1 (n=31) non-ischaemic (TBI≥0.75, ABI≥0.9), Group 2 (n=67) isolated low TBI with foot ischaemia (TBI<0.75, ABI≥0.90) and Group 3 (n=30) foot–leg ischaemia (TBI<0.75, ABI<0.90). Results: A total of 128 patients took part in the study. Low TBI was associated with a significant decrease in patient survival (42±20 versus 51±16 months, p=0.011). There was a progressive and significant decline in mean patient survival time (51±16 versus 44±20 versus 39±22 months, respectively, for ANOVA across the three groups, p=0.04). Patients with isolated low TBI had angioplasty and bypass at a rate similar to that of patients in Group 3 (low ABI and low TBI). The proportion of angioplasties was significantly higher in the isolated low TBI (19.4% (13/67) versus the non-ischaemic 3.2% (1/31), p=0.033). Such revascularisation resulted in ulcer healing within the foot ischaemic group that was similar to the non-ischaemic group (68% versus 60% over 12 months, p=0.454). Conclusion: Regardless of ABI level, measurement of TBI identifies patients with isolated low TBI who require specialised care pathways and revascularisation to achieve ulcer healing that is similar to non-ischaemic patients.