Toe Pressure and Toe Brachial Index are Predictive of Cardiovascular Mortality, Overall Mortality, and Amputation Free Survival in Patients with Peripheral Artery Disease

Abstract

Objective/background: Peripheral haemodynamic parameters are used to assess the presence and severity of peripheral artery disease (PAD). The prognostic value of ankle brachial index (ABI) has been thoroughly delineated. Nonetheless, the relative usefulness of ankle pressure (AP), ABI, toe pressure (TP), and toe brachial index (TBI) in assessing patient outcome has not been investigated in a concurrent study setting. This study aimed to resolve the association of all four non-invasive haemodynamic parameters in clinically symptomatic patients with PAD with cardiovascular mortality, overall mortality, and amputation free survival (AFS).

Methods: In total, 732 symptomatic patients with PAD admitted to the Department of Vascular Surgery for conventional angiography at Turku University Hospital, Turku, Finland, between January 2009 and August 2011 were reviewed retrospectively. Demographic factors, cardiovascular mortality, all-cause mortality, and above foot level amputations were obtained and assessed in relation to AP, ABI, TP, and TBI by means of Kaplan-Meier life tables and a multivariate Cox regression model.

Results: The haemodynamic parameter that was associated with poor 36 month general outcome was TP < 30 mmHg. Univariate Cox regression analysis of stratified values showed that TP and TBI associated significantly with mortality. In multivariate analysis both TP and TBI were associated with a significant risk of death. For TP < 30 mmHg and TBI < 0.25 the risk of cardiovascular mortality was hazard ratio [HR] 2.84, 95% confidence interval [CI] 1.75-4.61 [p<.001]; HR 3.68, 95% CI 1.48-9.19 [p=.050], respectively; all-cause mortality (HR 2.05, 95% CI 1.44-2.92 [p<.001]; HR 2.53, 95% CI 1.35-4.74 [p=.040], respectively); and amputation or death (HR 2.13, 95% CI 1.52-2.98 [p<.001]; HR 2.46, 95% CI 1.38-4.40 [p=.050], respectively)...

Conclusion: Among non-invasive haemodynamic measurements and pressure indices both TP and TBI appear to be associated with cardiovascular and overall mortality and AFS for patients with PAD presenting symptoms of the disease.

Keywords: ABI; Amputation free survival; Ankle pressure; Mortality; TBI; Toe pressure.