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Background: Patients with schizophrenia have an increased prevalence of risk factors for peripheral artery disease (PAD) and is expected to have an increased prevalence of PAD. PAD can be detected utilizing toe-brachial index (TBI) which screens for vascular pathology proximal to the toes.Methods: Using a cross-sectional design, we defined the subpopulations: (1) Patients diagnosed with schizophrenia less than 2 years before inclusion (SCZ < 2), (2) Psychiatric healthy controls matched to subpopulation 1 on sex, age, and smoking status, and (3) Patients diagnosed with schizophrenia 10 or more years before inclusion (SCZ ≥ 10). TBI was calculated by dividing toe pressures by systolic brachial blood pressure, and PAD was defined by TBI < 0.70. Logistic regression analysis with PAD as outcome and sex, age, smoking status, BMI, skin temperature, diagnosis of schizophrenia, and comorbidities as explanatory variables was conducted.Results: PAD was present in 26.2% of patients diagnosed with SCZ < 2 (17 of 65) and in 18.5% of psychiatric healthy controls (12 of 65) with no statistically significant difference in prevalence rates (p = 0.29). PAD was present in 22.0% of patients diagnosed with SCZ ≥ 10 (31 of 141). In logistic regression, patients diagnosed with SCZ < 2 had an increased odds of PAD with psychiatric healthy controls as reference (Odds ratio = 2.80, 95% confidence interval 1.09-7.23, p = 0.03). The analysis was adjusted for age, sex, smoking status, BMI and comorbidities such as hypertension, diabetes and heart disease.Conclusions: This study did not find statistically significant increased prevalence rates of PAD in patients with schizophrenia even though patients with SCZ were compared to psychiatric healthy controls using TBI. Utilizing logistic regression PAD was associated with schizophrenia diagnosis within the last 2 years, age and skin temperature. As PAD is initially asymptomatic, screening could be relevant in patients with schizophrenia if other risk factors are prevalent. Further large-scale multicenter studies are warranted to investigate schizophrenia as a potential risk factor for PAD.Trial registration: Clinicaltrials.gov identifier NCT02885792. Background: Patients with schizophrenia have an increased prevalence of risk factors for peripheral artery disease (PAD) and is expected to have an increased prevalence of PAD. PAD can be detected utilizing toe–brachial index (TBI) which screens for vascular pathology proximal to the toes. Methods: Using a cross-sectional design, we defined the subpopulations: (1) Patients diagnosed with schizophrenia less than 2 years before inclusion (SCZ < 2), (2) Psychiatric healthy controls matched to subpopulation 1 on sex, age, and smoking status, and (3) Patients diagnosed with schizophrenia 10 or more years before inclusion (SCZ ≥ 10). TBI was calculated by dividing toe pressures by systolic brachial blood pressure, and PAD was defined by TBI < 0.70. Logistic regression analysis with PAD as outcome and sex, age, smoking status, BMI, skin temperature, diagnosis of schizophrenia, and comorbidities as explanatory variables was conducted. Results: PAD was present in 26.2% of patients diagnosed with SCZ < 2 (17 of 65) and in 18.5% of psychiatric healthy controls (12 of 65) with no statistically significant difference in prevalence rates (p = 0.29). PAD was present in 22.0% of patients diagnosed with SCZ ≥ 10 (31 of 141). In logistic regression, patients diagnosed with SCZ < 2 had an increased odds of PAD with psychiatric healthy controls as reference (Odds ratio = 2.80, 95% confidence interval 1.09–7.23, p = 0.03). The analysis was adjusted for age, sex, smoking status, BMI and comorbidities such as hypertension, diabetes and heart disease. Conclusions: This study did not find statistically significant increased prevalence rates of PAD in patients with schizophrenia even though patients with SCZ were compared to psychiatric healthy controls using TBI. Utilizing logistic regression PAD was associated with schizophrenia diagnosis within the last 2 years, age and skin temperature. As PAD is initially asymptomatic, screening could be relevant in patients with schizophrenia if other risk factors are prevalent. Further large-scale multicenter studies are warranted to investigate schizophrenia as a potential risk factor for PAD. Trial registration: Clinicaltrials.gov identifier NCT02885792.

Background: Peripheral arterial disease (PAD) in the presence of a normal ankle-brachial index (ABI) can be diagnosed noninvasively by measuring a postexercise ABI or by measuring the toe-brachial index (TBI). Methods: This was a prospective comparative study. Over a period of 30 months, a total of 415 patients who were referred with the suspicion of vascular claudication and resting values of 0.91 ≤ ABI1.10 (P ≤ 0.022 for both), but there were no statistically significant differences found in other ABI intervals (P > 0.200 for all). Conclusions: The magnitude of the TBI reduction correlates with an increased probability of an abnormal postexercise ABI. However, this is due in part to limbs with a low TBI having a lower resting ABI on average than limbs with a normal TBI, which also correlates with the probability of an abnormal exercise test result. This study shows that the TBI and the postexercise ABI are not interchangeable for establishing a PAD diagnosis.

BACKGROUND AND AIMS: Classically, peripheral arterial disease (PAD) is diagnosed by a low ankle-brachial index (ABI), but the diagnosis can also be made based on toe-brachial index (TBI) measurements. The objective of this study was to characterize patients with low TBI but normal ABI, and chart potential underestimation of PAD prevalence by solitary use of ABI.METHODS: A total of 3739 consecutive patients with known or suspected PAD referred for ABI and TBI measurements in a four-year period were compared to an age- and gender matched control group (n = 17,340).RESULTS: In the patient cohort, 65.0% had low ABI, 20.5% had low TBI but normal ABI, and 14.5% had normal indices. When comparing the frequencies of comorbidities related to atherosclerotic disease (myocardial infarction, congestive heart failure, cerebrovascular disease, diabetes mellitus, chronic kidney failure), there were no significant differences among patients with low ABI or low TBI with normal ABI in any of the variables (all p > 0.06). Of the patients with low TBI and normal ABI, 18.7% were diagnosed with diabetes mellitus type I or II, and 8.2% with chronic kidney disease.CONCLUSIONS: Patients with low TBI but normal ABI represented 20.5% of patients referred with the suspicion of PAD. Furthermore, patients with low TBI but normal ABI presented similar comorbid characteristics to patients with low ABI, who have a well-described increased risk of cardiovascular morbidity and mortality. The solitary use of ABI underestimated the prevalence of PAD in the population, and PAD screening could potentially be improved by routine application of TBI.

Objective: In patients with peripheral arterial disease (PAD), measurements of distal blood pressure form the basis of assessing the severity of the disease along with symptoms and objective findings. The reliability and accuracy of a fully automated bedside device (SysToe) vs. strain gauge plethysmography (SGP) in patients with low toe pressures in a bedside setting in an outpatient clinic of vascular surgery were investigated. Methods: This was a prospective, single blinded study carried out in compliance with the Standards of Reporting of Diagnostic Accuracy Studies. A total of 94 outpatients with symptomatic PAD in an outpatient vascular surgery clinic were included and had index measurements performed with the automated bedside device in a bedside setting by observers with no training in routine distal pressure measurements. SGP reference measurements were performed in a vascular laboratory. Results: There was agreement between modalities regarding the diagnostic classification of chronic limb threatening ischaemia (CLTI) in 79/94 (84%) patients. For detection of CLTI, Cohen's kappa was 0.57 with a sensitivity of 94%, specificity of 82%, positive predictive value (PPV) 52%, and negative predictive value (NPV) 98%. On average, the automated bedside device underestimated the pressures, compared with the SGP. The mean difference between SGP and SysToe was 9 ± 16 mmHg for right limbs and 10 ± 16 mmHg for left limbs (p < .001). Conclusion: The automated bedside device showed a high sensitivity and a high NPV for excluding CLTI. However, the low PPV may result in overdiagnosis. The automated bedside device may function as a screening tool identifying patients in need of further diagnostics with more accurate equipment, for example SGP.

ObjectiveTo assess the accuracy of a fully automated portable device (APD) for diagnosing peripheral arterial disease (PAD) by measuring the toe–brachial index (TBI) and using mercury-in-silastic, strain-gauge plethysmography (SGP) as reference.DesignProspective, randomised, double-blinded diagnostic accuracy study.Materials and methodsA total of 204 consecutive patients with known or suspected PAD were randomly assigned to measurement of TBI by the portable device followed by the SGP technique or the opposite sequence. Finally, ankle–brachial index (ABI) was assessed by SGP.ResultsThe APD showed a sensitivity of 98.8%, a specificity of 61.0%, a positive predictive value of 91.0% and a negative predictive value of 92.6% for detecting PAD compared to a full SGP test comprised of ABI and TBI. According to the SGP test, 35 patients (17.2%) had an ABI > 0.90 but a TBI

BACKGROUND Warm ischemia and subsequent reperfusion of the heart can induce a temporary dysfunction known as myocardial stunning. The aim of this study was to investigate the ability of tissue Doppler imaging (TDI) to quantify longitudinal myocardial stunning close to the apex, and perform a comparison with sonomicrometry using a well-established large size porcine model. METHODS In anesthetized pigs, postischemic myocardial stunning was induced by occluding LAD for 15 min followed by 90 min reperfusion (n = 7). Long-axis strain and strain rate was quantified by both TDI and sonomicrometry. RESULTS During reperfusion, peak systolic strain measured by TDI decreased from -11.2% (+/-3.0) at baseline to -4.9% (+/-3.6), -3.4% (+/-2.9), and -4.3% (+/-5.0) at 30, 60, and 90 min, respectively (all P < 0.007). Postsystolic strain increased from -1.3% (+/-1.6) at baseline to -6.4% (+/-4.4), -4.8% (+/-4.0), and -5.2% (+/-2.7) by TDI in the reperfusion phase (all P < 0.048 except at 60 min of reperfusion (P = 0.081)). Postsystolic index increased from 0.10 (+/-0.13) at baseline to 0.56 (+/-0.24), 0.54 (+/-0.30), and 0.64 (+/-0.37) subsequently (all P < 0.012). [Correction added after online publication 30-May-2007: In the preceding sentence, the phrase 'Postsystolic index decreased from 0.10 (+/-0.13)' was changed to 'Postsystolic index increased from 0.10 (+/-0.13).'] Difference-mean and line of identity plots did not disclose any systematic error, but revealed substantial variation, indicating a mismatch between TDI and sonomicrometry. CONCLUSIONS It is feasible to quantify postischemic myocardial stunning by TDI in a large size porcine model using longitudinal postsystolic shortening, and postsystolic index as indicators. TDI and sonomicrometry data reach the same end point, but the two techniques are not interchangeable when investigating myocardial stunning close to apex in reference to longitudinal strain and strain rate.

Objectives To assess the intra- and inter-observer variation in laser Doppler flowmetry curve reading for measurement of toe and ankle pressures. Methods A prospective single blinded diagnostic accuracy study was conducted on 200 patients with known or suspected peripheral arterial disease (PAD), with a total of 760 curve sets produced. The first curve reading for this study was performed by laboratory technologists blinded to clinical clues and previous readings at least 3 months after the primary data sampling. The pressure curves were later reassessed following another period of at least 3 months. Observer agreement in diagnostic classification according to TASC-II criteria was quantified using Cohen's kappa. Reliability was quantified using intra-class correlation coefficients, coefficients of variance, and Bland–Altman analysis. Results The overall agreement in diagnostic classification (PAD/not PAD) was 173/200 (87%) for intra-observer ( κ = .858) and 175/200 (88%) for inter-observer data ( κ = .787). Reliability analysis confirmed excellent correlation for both intra- and inter-observer data (ICC all ≥.931). The coefficients of variance ranged from 2.27% to 6.44% for intra-observer and 2.39% to 8.42% for inter-observer data. Subgroup analysis showed lower observer-variation for reading of toe pressures in patients with diabetes and/or chronic kidney disease than patients not diagnosed with these conditions. Bland–Altman plots showed higher variation in toe pressure readings than ankle pressure readings. Conclusions This study shows substantial intra- and inter-observer agreement in diagnostic classification and reading of absolute pressures when using laboratory technologists as observers. The study emphasises that observer variation for curve reading is an important factor concerning the overall reproducibility of the method. Our data suggest diabetes and chronic kidney disease have an influence on toe pressure reproducibility.

BackgroundPeripheral arterial disease (PAD) can be diagnosed noninvasively by segmental blood pressure measurement and calculating an ankle-brachial index (ABI) or toe-brachial index (TBI). The ABI is known to be unreliable in patients with vascular stiffness and fails to detect the early phase of arteriosclerotic development. The toe vessels are less susceptible to vessel stiffness, which makes the TBI useful. However, the diagnostic limits used in guidelines, clinical settings, and experimental studies vary substantially. This review provides an overview of the evidence supporting the clinical use of the TBI.MethodsA review of the literature identified studies reporting the use of the TBI regarding guideline recommendations, normal populations, correlations to angiographic findings, and prognostic implications.ResultsEight studies conducted in a normal population were identified, of which only one study used imaging techniques to rule out arterial stenosis. A reference value of 0.71 was estimated as the lowest limit of normal based on the weighted average in studies with preheating of the limbs. A further seven studies showed correlations of the TBI with angiographic findings. The TBI had a sensitivity of 90% to 100% and a specificity of 65% to 100% for the detection of vessel stenosis. Few studies investigated the value of the TBI as a prognostic marker for cardiovascular mortality and morbidity, and no firm conclusions could be made. Studies have, however, shown correlation between the TBI and comorbidities such as kidney disease, diabetes, and microvasculature disease.ConclusionsIn contrast to the well-defined and evidence-based limits of the ABI, the diagnostic criteria for a pathologic TBI remain ambiguous. Although several guidelines and reviews of PAD diagnostics recommend a TBI

Objective Mitral valve replacement with preservation of the entire subvalvular apparatus entails superior postoperative left ventricular function compared with other techniques. However, this option is often not possible because of valve pathology. We hypothesized that preservation of only 4 mitral valve secondary ("strut") chordae would be functionally and geometrically equivalent to total valve preservation in the long-term setting. In a porcine mitral valve replacement model we investigated the long-term effects of 3 surgical techniques on left ventricular function and geometry: (1) total preservation of the native valve, (2) strut chordal preservation, and (3) total excision of the subvalvular apparatus. Methods Forty 60-kg pigs were randomized to 1 of the 3 techniques. Global and regional left ventricular function and dimensions were assessed with cardiovascular magnetic resonance and conductance catheter 90 days after mitral valve replacement. Groups were compared by multivariate analysis of variance. Results There was no overall difference between groups 1 and 2. Group 3 animals had (1) greater base-apex diastolic and systolic lengths, and smaller short-axis diameters, and (2) lower sphericity indices, and greater base-apex and short-axis fractional shortening than groups 1 and 2. Regional analysis showed slimming and elongation to occur primarily in the basal left ventricular segments. Left ventricular contractility and hemodynamic parameters did not differ between groups. Conclusions Strut chordal preservation was equivalent to total valve preservation during mitral valve replacement, whereas total chordal resection caused significant left ventricular slimming with compensatory increases in fractional shortening. Therefore, to preserve left ventricular geometry, special attention must be paid to maintain the valvular–ventricular continuity through the strut chordae during mitral valve replacement. This concept may have important therapeutic implications for chordal-sparing mitral valve replacement.

ObjectiveTo assess the diagnostic accuracy of laser Doppler flowmetry (LDF) with mercury-in-silastic strain gauge plethysmography (SGP) as a reference test for measuring the toe and ankle pressures in patients with known or suspected peripheral arterial disease (PAD).MethodsThis was a prospective, randomized, blinded diagnostic accuracy study. Toe and ankle pressures were measured using both methods in 200 consecutive patients, who were recruited at our vascular laboratory over a period of 30 working days. Classification of PAD and critical limb ischemia (CLI) was made in accordance with TASC-II criteria.ResultsThe LDF method demonstrated 5.8 mm Hg higher mean toe pressures than the SGP method for the right limb and 7.0 mm Hg for the left limb (both P < .001). There were no significant differences in the mean ankle pressures (both P > .129). The limits of agreement for the differences (SGP − LDF) were −31.7 to 20.2 mm Hg for right toe pressures, −28.0 to 14.0 mm Hg for left toe pressures, −25.5 to 22.8 mm Hg for right ankle pressures, and −26.9 to 24.6 mm Hg for left ankle pressures. A correlation analysis of the absolute pressures using the two methods showed an intraclass correlation coefficient of 0.902 (95% confidence interval [CI], 0.835-0.938) for right toe pressures, 0.919 (95% CI, 0.782-0.960) for the left toe pressures, 0.953 (95% CI, 0.937-0.965) for right ankle pressures, and 0.952 (95% CI, 0.936-0.964) for left ankle pressures. Cohen's Kappa showed an agreement in the diagnostic classification of κ = 0.775 (95% CI, 0.631-0.919) for PAD and κ = 0.780 (95% CI, 0.624-0.936) for CLI.ConclusionsLDF showed a good correlation with SGP over a wide range of toe and ankle pressures, as well as substantial agreement for the diagnostic classification of PAD including CLI.