Duplex ultrasound assessment of early-stage peripheral artery disease in the lower limbs of Zimbabwean diabetic patients

Tityiwe, JS 2020, Duplex ultrasound assessment of early-stage peripheral artery disease in the lower limbs of Zimbabwean diabetic patients , PhD thesis, University of Salford.

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Abstract

Keywords: Spectral Doppler imaging, peak systolic velocity, pulsatility index, vessel diameter, resistive index, nitrite, nitric oxide, systolic blood pressure, diastolic blood pressure. Objectives: i) To determine the repeatability of ultrasound parameters in measuring blood flow in diabetic patients with early-stage peripheral artery disease (PAD); ii) To determine whether there is a difference in blood flow between the diabetic lower limb arteries with early-stage PAD and non-diabetic controls. iii) To determine the acute effects of beetroot juice ingestion on blood flow and blood pressure in diabetic patients with early-stage PAD compared to non-diabetic controls. Methods: In the first investigation, within and between sessions reliability intraclass correlation coefficients [ICC], percentage coefficient of variation [%CV]), measurement error (standard error of measurement [SEM] and smallest detectable difference [SDD] were calculated for peak systolic velocity (PSV), resistive index (RI), pulsatility index (PI), and vessel diameter inner to the inner (VDI) to establish their repeatability in measuring blood flow in the popliteal arteries [PA], anterior tibial arteries [ATA] and posterior tibial arteries [PTA] of diabetic patients with early-stage peripheral artery disease [PAD]. Paired t-tests were performed and effect sizes calculated to establish if the differences between sessions were significant or meaningful. In the second investigation, PSV, RI and PI were compared between diabetic lower limb arteries with early-stage PAD and non-diabetic controls. Two samples of t-test and effect sizes were performed to determine if differences between groups were significant or meaningful. In the third investigation, PSV, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were utilised to assess blood flow in the PA, 90 minutes, 150 minutes and 210 minutes after ingestion of beetroot juice and compared between groups. Two-way analyses of variance and posthoc analyses were performed to compare the two groups across 4 - time points after the intake of beetroot juice, with a series of one sample and two samples t-tests, performed and effect sizes calculated to compare dependent variables within and between groups at individual time points respectively. Results: In the first investigation, PSV, PI and RI showed very good (ICC ≥0.8; 0.6 – 0.9, 95% CI) to excellent (ICC ≤1.0; 1.0 -1.0, 95% CI) reliability and acceptably low variability (≤5.6%CV) both within and between sessions. The SEM was acceptably low (SEM ≤1.1) with low SDD (SDD <10%) for all parameters other than VDI-PTA (SDD = 13.6%). In the second investigation, PSV and RI were significantly and meaningfully higher (P <0.05; d ≥2.1), in diabetic patients compared to controls, other than PI-PTA (P >0.05; d ≤0.3). In the third investigation, within groups PSV, SBP and DBP reduced significantly and meaningfully across all time points (p ≤0.02; d ≥1.7), However, SBP and PSV showed no significant or meaningful difference between groups only during the 150 - 210 minutes time point (p < 0.0001) while DBP showed no significant or meaningful difference between groups throughout all time points. Conclusions: PSV, PI and RI were robust in measuring blood flow in the lower limbs of diabetic patients with early-stage PAD except for VDI (investigation 1). PSV and RI demonstrated effects of early-stage PAD in the lower limbs diabetic patients except for PI-PTA (investigation 2). Beetroot juice ingestion resulted in a significant reduction of PSV, SBP and DBP in the PA during the 150 - 210 minutes time points (investigation 3). Correspondence to: Josephine S Tityiwe, National University of Science and Technology, Radiography Department, Corner Cecil/Gwanda Road, P. O. Box AC 939 Ascot, Bulawayo, Zimbabwe. Email: josephine.tityiwe@nust.ac.zw/ J.S.Tityiwe@edu.salford.ac.uk

Item Type: Thesis (PhD)
Contributors: Comfort, P (Supervisor)
Schools: Schools > School of Health Sciences
Funders: National University of Science and Technology, Bulawayo, Zimbabwe
Depositing User: Josephine Sekai Tityiwe
Date Deposited: 21 Apr 2021 15:14
Last Modified: 27 Aug 2021 21:51
URI: http://usir.salford.ac.uk/id/eprint/59777

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