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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: Chronic mesenteric ischaemia (CMI) is a vastly underdiagnosed condition that typically leads to postprandial abdominal pain and weight loss. The aim of the study was to explore the involvement of various mesenteric vessels in total splanchnic blood flow (SBF) and hepatic vein oxygenation. Methods: Single-blinded comparative trial of 476 patients clinically suspected of CMI. Routine investigation included measurement of hepatic vein oxygen saturation, indirect measurement of the total splanchnic blood flow (SBF), using Fick's principle and the tracer [ 99mTc]Mebrofenin, before and after a meal, and digital subtraction angiography. Results: A total of 176 of the 476 patients (36%) had at least one angiographically significant stenosis (lumen reduction ≥70%). In patients with a significant one-vessel disease, the percentage having CMI according to SBF was 10% for a celiac trunk stenosis (n = 60), 50% for a superior mesenteric stenosis (n = 24) and 6% for an inferior mesenteric artery stenosis (n = 34). In patients with a significant two-vessel disease, the percentage with CMI according to SBF response was 92%, 18% and 79%, for no significant stenosis of the celiac trunk (n = 13), superior mesenteric artery (n = 17) and inferior mesenteric artery (n = 19), respectively. Conclusion: Patients with significant one- or two-vessel stenosis involving the superior mesenteric artery have a higher likelihood of CMI according to flow criteria and a greater postprandial decrease in hepatic vein saturation on average than patients with no involvement of the superior mesenteric artery.

Ventilation/perfusion single-photon emission computed tomography performed using an aerosol of carbon-coated technetium is frequently used for diagnosing pulmonary embolism. Certain patients may suffer from chronic obstructive pulmonary disease (COPD); for such patients, the formation of mucus clots in airways can cause accumulation of the aerosol in the larger airways. This centralized deposition of the aerosol leads to insufficient activity in peripheral lung segments and subsequently results in ventilation images of substandard or even nondiagnostic quality. Continuous positive airway pressure (CPAP) therapy improves airway dynamics and quality of life for COPD patients. We report for the first time the results for two patients for whom initial ventilation scans were of insufficient quality, but diagnostic-quality images were obtained after CPAP therapy.

AIM: To examine the interchangeability of two methods for distal pressure measurement based on photoplethysmography using a truncated or full display of the arterial inflow curve, respectively.METHODS: Toe and ankle pressures were obtained from 69 patients suspected of peripheral arterial disease (PAD). Observer reproducibility of the curve readings was examined by blinded reassessment of the pressure curves in a randomly selected subgroup (60 limbs).RESULTS: There were no significant differences in mean pressures between the two methods (p for all > .455). The limits of agreement for the differences were -15.0-15.4 mmHg for right toe pressures, -16.3-16.2 mmHg for left toe pressures, -14.2-15.7 mmHg for right ankle pressures, and -18.3-17.7 mmHg for left ankle pressures. Correlation analysis revealed intraclass correlation coefficients ≥0.960 for all measuring sites. Cohen's Kappa showed excellent agreement in diagnostic classification, with κ = 0.930 for the diagnosis of PAD and perfect agreement in the diagnosis of critical limb ischemia (κ = 1.000). The analysis of intra-observer variation for curve reading showed limits of agreement of -3.9-4.0 for toe pressures and -7.6-7.7 for ankle pressures for the method involving truncated display and -3.1-3.2 for toe pressures and -6.3-8.6 for ankle pressures for the method involving full display of the signal.CONCLUSION: The present study shows minimal differences in diagnostic classification, as well as in ankle and toe pressures, between the full display and the truncated display of the photoplethysmographic pulse signal. Furthermore, the inter-observer variation was low for both of the photoplethysmographic methods investigated.

Mercury-in-silastic strain gauge pletysmography (SGP) is a well-established technique for blood flow and blood pressure measurements. The aim of this study was to examine (i) the possible influence of clinical clues, e.g. the presence of wounds and color changes during blood pressure measurements, and (ii) intra- and inter-observer variation of curve interpretation for segmental blood pressure measurements.A total of 204 patients with known or suspected peripheral arterial disease (PAD) were included in a diagnostic accuracy trial. Toe and ankle pressures were measured in both limbs, and primary observers analyzed a total of 804 pressure curve sets. The SGP curves were later reanalyzed separately by two observers blinded to clinical clues. Intra- and inter-observer agreement was quantified using Cohen's kappa and reliability was quantified using intra-class correlation coefficients, coefficients of variance, and Bland-Altman analysis.There was an overall agreement regarding patient diagnostic classification (PAD/not PAD) in 202/204 (99.0%) for intra-observer (κ = 0.969, p0.001), and 201/204 (98.5%) for inter-observer readings (κ = 0.953, p0.001). Reliability analysis showed excellent correlation between blinded versus non-blinded and inter-observer readings for determination of absolute segmental pressures (all intraclass correlation coefficients ≥ 0.984). The coefficient of variance for determination of absolute segmental blood pressure ranged from 2.9-3.4% for blinded/non-blinded data and from 3.8-5.0% for inter-observer data.This study shows a low inter-observer variation among experienced laboratory technicians for reading strain gauge curves. The low variation between blinded/non-blinded readings indicates that SGP measurements are minimally biased by clinical clues.

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.

We examine the reliability of single and repeated blood pressure measurements at ankle, toe, and arm levels for the diagnosis of peripheral arterial disease (PAD) by laser Doppler flowmetry. Segmental pressures were measured in 200 patients with known or suspected PAD. Segmental indices were calculated using (1) one measurement [M-1], two measurements [M-2], or by a predefined reproducibility criterion (RC) as well as (2) by using one brachial blood-pressure (BBP-one) or correspondent to each segmental pressure (BBP-all) as reference. The agreement in diagnosis of PAD by Cohen's Kappa was κ = 0.930 when comparing RC to M-1, and κ = 0.977 when comparing RC to M-2. The same comparison showed excellent relative reliability for segmental indices (all intra-class correlation coefficients (ICC) ≥ 0.980). Diagnostic classification agreement for BBP-all versus BBP-one were κ = 0.831 for RC, κ = 0.804 for M-1, and κ = 0.847 for M-2. The relative reliability analysis showed excellent correlation in segmental indices (all ICC ≥ 0.957). The study shows minimal difference in segmental indices and diagnostic classification when comparing calculations based on the listed strategies. However, the study indicated that it is important to measure BBPs correspondent to each segmental pressure.

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.