DNA-Binding Proteins and Passenger Proteins in Plasma DNA-Protein Complexes: Imprint of Parental Cells or Key Mediators of Carcinogenesis Processes?

Knowledge of the composition of proteins that interact with plasma DNA will provide a better understanding of the homeostasis of circulating nucleic acids and the various modes of interaction with target cells, which may be useful in the development of gene targeted therapy approaches. The goal of the present study is to shed light on the composition and architecture of histone-containing nucleoprotein complexes (NPCs) from the blood plasma of healthy females (HFs) and breast cancer patients (BCPs) and to explore the relationship of proteins with crucial steps of tumor progression: epithelial-mesenchymal transition (EMT), cell proliferation, invasion, cell migration, stimulation of angiogenesis, and immune response. MALDI-TOF mass spectrometric analysis of NPCs isolated from blood samples using affine chromatography was performed. Bioinformatics analysis showed that the shares of DNA-binding proteins in the compositions of NPCs in normal and cancer patients are comparable and amount to 40% and 33%, respectively; in total, we identified 38 types of DNA-binding motifs. Functional enrichment analysis using FunRich 3.13 showed that, in BCP blood, the share of DNA-binding proteins involved in nucleic acid metabolism increased, while the proportion of proteins involved in intercellular communication and signal transduction decreased. The representation of NPC passenger proteins in breast cancer also changes: the proportion of proteins involved in transport increases and the share of proteins involved in energy biological pathways decreases. Moreover, in the HF blood, proteins involved in the processes of apoptosis were more represented in the composition of NPCs and in the BCP blood-in the processes of active secretion. For the first time, bioinformatics approaches were used to visualize the architecture of circulating NPCs in the blood and to show that breast cancer has an increased representation of passenger proteins involved in EMT, cell proliferation, invasion, cell migration, and immune response. Using breast cancer protein data from the Human Protein Atlas (HPA) and DEPC, we found that 86% of NPC proteins in the blood of BCPs were not previously annotated in these databases. The obtained data may indirectly indicate directed protein sorting in NPCs, which, along with extracellular vesicles, can not only be diagnostically significant molecules for liquid biopsy, but can also carry out the directed transfer of genetic material from donor cells to recipient cells.

Volatile versus Total Intravenous Anesthesia for Coronary Artery Bypass Graft Surgery: Analysis of 1586 MYRIAD Trial Patients Managed with the Same Perioperative Protocol.

Background: This study investigated the influence of volatile anesthesia (VA) on major complications and mortality in patients undergoing coronary artery bypass graft surgery (CABG). Methods: This post-hoc analysis included 1586 patients from the MYRIAD trial managed using the same perioperative protocol at a single institution. Patients were randomized to receive either volatile anesthesia (sevoflurane, isoflurane, or desflurane) or total intravenous anesthesia (TIVA). The assessed study outcomes were the rate of complications, including: myocardial infarction, stroke, acute kidney injury, prolonged ventilation ( > 24 h), receipt of high-dose inotropic support (inotropic score > 10), and need for mechanical circulatory support. The duration of intensive care unit (ICU) stay, length of hospitalization, hospital readmission during follow-up, 30-days and 1-year mortality were also analyzed. Results: 1586 patients were enrolled between September 2014-September 2017 and randomly assigned to the volatile anesthesia group (n = 794) and the TIVA group (n = 792). The median patient age was 63 years, with a median ejection fraction of 60%. There were no significant differences in the rates of major complications, duration of ICU stay, and hospitalization between the groups. The median total dose of fentanyl was 12.0 mcg/kg in volatile group and 14.4 mcg/kg in TIVA group (p < 0.001). One-year mortality rates were 2.5% (n = 20) and 3.2% (n = 25) in the volatile and TIVA groups, respectively. Two patients were lost at the 30-day and 1-year follow-ups in the volatile group compared to four patients in TIVA group. Regression analysis showed that cardiopulmonary bypass (CPB) duration, fentanyl dose, and baseline serum creatinine level were associated with 30-days mortality, while ejection fraction was associated with 1-year mortality. Conclusions: The use of VA in patients undergoing CABG did not result in a reduction in major complications or mortality compared with TIVA. A higher dose of fentanyl was used in the TIVA group and was associated with an increase in the 30-days mortality. These findings warrant further investigation. Clinical Trial Registration: ClinicalTrials.gov (NCT02105610).

The effect of the stented iliac lesions TASC-II C, D on the femoropopliteal bypass patency: Propensity score-matched observational study.

INTRODUCTION: Concurrent stenting of complex iliac lesions during infrainguinal bypasses can increase the complexity of a case and impact outcomes. OBJECTIVE: Our aim was to evaluate the effect of inflow stenting of TASC-II C, D iliac lesions on femoropopliteal bypass patency. METHODS: A retrospective observational cohort study of patients who underwent femoropopliteal bypass with TASC-II C, D iliac artery stenting (hybrid group) or without inflow lesions (non-hybrid group) was conducted. After propensity score matching, 120 patients were included in the non-hybrid group and 60 patients in the hybrid one. The median follow-up was 432 (193; 1313) days in the hybrid group and 472 (196; 1376) days in the non-hybrid group (p = 0.94). RESULTS: No significant differences were found between the groups in 30-day morbidity and serious adverse events. At 3 years, primary and secondary bypass patency for the hybrid group and non-hybrid group were 62.2% versus 59.9% (p = 0.36) and 63.7% versus 64.3% (p = 0.077), respectively. The primary patency of the iliac stents in patients of the hybrid group was 95% at 3 years. The estimated hazard ratio for primary patency for hybrid versus non-hybrid was 0.77, with 90% CI: 0.50-1.21; the noninferiority upper bound being 1.31, which corresponds to a 10% additive noninferiority margin for probabilities. The 3 years of freedom from amputation in patients with chronic limb-threatening ischemia was 94.1% and 75.0% in the hybrid and non-hybrid groups, respectively (p = 0.09). CONCLUSION: The outcomes of the femoropopliteal bypass in hybrid surgery supplemented with stenting of TASC-II C, D iliac lesions was similar to femoropopliteal bypass with intact inflow arteries.

Opioid-Sparing Cardiac Anesthesia: Secondary Analysis of an Enhanced Recovery Program for Cardiac Surgery.

BACKGROUND: Cardiac anesthetics rely heavily on opioids, with the standard patient receiving between 70 and 105 morphine sulfate equivalents (MSE; 10-15 µg/kg of fentanyl). A central tenet of Enhanced Recovery Programs (ERP) is the use of multimodal analgesia. This study was performed to assess the association between nonopioid interventions employed as part of an ERP for cardiac surgery and intraoperative opioid administration. METHODS: This study represents a post hoc secondary analysis of data obtained from an institutional ERP for cardiac surgery. Consecutive patients undergoing cardiac surgery received 5 nonopioid interventions, including preoperative gabapentin and acetaminophen, intraoperative dexmedetomidine and ketamine infusions, and regional analgesia via serratus anterior plane block. The primary objective, the association between intraoperative opioid administration and the number of interventions provided, was assessed via a linear mixed-effects regression model. To assess the association between intraoperative opioid administration and postoperative outcomes, patients were stratified into high (>50 MSE) and low (≤50 MSE) opioids, 1:1 propensity matched based on 15 patients and procedure covariables and assessed for associations with postoperative outcomes of interest. To investigate the impact of further opioid restriction, ultralow (≤25 MSE) opioid participants were then identified, 1:3 propensity matched to high opioid patients, and similarly compared. RESULTS: A total of 451 patients were included in the overall analysis. Analysis of the primary objective revealed that intraoperative opioid administration was inversely related to the number of interventions employed (estimated -7.96 MSE per intervention, 95% confidence interval [CI], -9.82 to -6.10, P < .001). No differences were detected between low (n = 136) and high (n = 136) opioid patients in postoperative complications, postoperative pain scores, time to extubation, or length of stay. No differences were found in outcomes between ultralow (n = 63) and high (n = 132) opioid participants. CONCLUSIONS: Nonopioid interventions employed as part of an ERP for cardiac surgery were associated with a reduction of intraoperative opioid administration. Low and ultralow opioid use was not associated with significant differences in postoperative outcomes. These findings are hypothesis-generating, and future prospective studies are necessary to establish the role of opioid-sparing strategies in the setting of cardiac surgery.

Comparative Analysis of Carotid Artery Stenting and Carotid Endarterectomy in Clinical Practice.

The objective of the study was to describe immediate and long-term results of carotid endarterectomy (CEA) versus carotid stenting (CAS) with embolic protection in patients with severe carotid artery stenosis in clinical practice. MATERIALS AND METHODS: This is a retrospective cohort study, conducted between 2009 and 2017. During the analyzed period, 2132 operations (2006 patients) were performed: 1215 (57%) CEA and 917 (43%) CAS. 278 patients (13.8% of 2006) were not contactable during the follow-up period (>30 days) leaving 1791 cases (1728 patients) for inclusion in the analysis. Propensity score matching was used to compare the treatment results of groups (561 cases were matched out of 1791). The results of 615 CEA (316 eversion, 299 "classic" with patch) and 615 CAS (using a variety of carotid stents) were compared. RESULTS: In the asymptomatic subgroup (n = 455), the 30-day rate of stroke was not significantly different between the CEA group and the CAS group (1.5% versus 2.4%, P = .48). The 5-year rate of stroke was not significantly higher for CAS than for CEA (4.6% versus 3.3%, P = .3). In the symptomatic subgroup (n = 160), the 30-day rate of stroke was significantly higher in the CAS group than in the CEA group (7.5% versus 2.5%, P = .04). The 5-year rate of stroke was 13% for CAS and 8.7% for CEA (P = .2). CONCLUSIONS: In the symptomatic subgroup, the 30-day rate of stroke was significantly higher in the CAS group than in the CEA group, therefore the use of CAS for symptomatic patients in routine practice should be limited. Our study demonstrates that the rates of stroke and survival after CEA and CAS in patients aged 80 years or younger with asymptomatic or symptomatic severe carotid stenosis did not differ significantly over a period of 5 years.

Pulse wave travel distance as a novel marker of ventricular-arterial coupling.

Each stroke volume ejected by the heart is distributed along the arterial system as a pressure waveform. How far the front of the pressure waveform travels within the arterial system depends both on the pulse wave velocity (PWV) and the ejection time (ET). We tested the hypothesis that ET and PWV are coupled together, in order to produce a pulse wave travel distance (PWTD = PWV × ET) which would match the distance from the heart to the most distant site in the arterial system. The study was conducted in 11 healthy volunteers. We recorded lead II of the ECG along with pulse plethysmography at ear, finger and toe. The ET at the ear and pulse arrival time to each peripheral site were extracted. We then calculated PWV followed by PWTD for each location. Taken into account the individual subject variability PWTDToe in the supine position was 153 cm (95% CI 146-160 cm). It was not different from arterial pathway distance from the heart to the toe (D Toe 153 cm). The PWTDFinger and PWTDEar were longer than the distance from the heart to the finger and ear irrespective of body position. ETEar and PWVToe appear to be coupled in healthy subjects to produce a PWTD that is roughly equivalent to the arterial pathway distance to the toe. We propose that PWTD should be evaluated further to test its potential as a noninvasive parameter of ventricular-arterial coupling in subjects with cardiovascular diseases.

Systemic Thrombolytic Therapy and Catheter-Directed Fragmentation with Local Thrombolytic Therapy in Patients with Pulmonary Embolism.

BACKGROUND: The objective was to compare immediate and long-term results of systemic thrombolytic therapy (STT) and catheter-directed fragmentation (CDF) with local thrombolytic therapy (LTT) in patients with massive pulmonary embolism (PE). METHODS: About 209 patients with massive PE (the high risk of early death) were included in our study. From 2008 till 2010 in the first group (n = 102), STT was performed. From 2011 till 2013 in the second group (n = 107), CDF with LTT was carried out. Echocardiography and pulmonary arteriography were performed in all patients on admission to hospital and in 5 days after treatment. The patients of both groups were re-examined in 6 months, 1, 2, and 3 years after the operation. RESULTS: In the first group, there were 5 (4.9%) cases of in-hospital 30-day mortality. In the second group, there was 1 (0.9%) case of in-hospital 30-day mortality (P = 0.08). In the first group, a clinically significant bleeding was noted in 4 (3.9%) cases, but it caused mortality only in 1 case. In the second group, the clinically significant bleeding was not found (P = 0.038). Persistent postembolic pulmonary hypertension (PPPH) in 9.8% cases of patients in the first group and 2.9% cases of patients in the second group was determined (P = 0.048). CONCLUSIONS: CDF combined with LTT is an effective minimal invasive treatment (helped us to reduce significantly the number of bleeding and PPPH cases), at least in the midterm, in patients with massive PE.

The role of stump pressure and cerebral oximetry in predicting ischaemic brain damage during carotid endarterectomy.

Objective is to compare the predictive value of stump pressure (SP) and cerebral oximetry (rSO2) levels in the evaluation of ischaemic injury of the cerebrum during clamping of the carotid artery (CCA) without temporary shunt (TS). Methods We included 84 patients with an asymptomatic stenosis (>70%) of the internal carotid artery (ICA) who underwent carotid endarterectomy (CEA) under GA. Cerebral ischaemic tolerance (CIT) was determined on the basis of SP, rSO2 and ∆rSO2 (↓rSO2 from baseline) during CCA. The levels of S100 protein (S100) and neuron-specific enolase (NSE) were measured on each stage of the study. MRI was performed for all patients. Results There were no perioperative strokes and myocardial infarctions during the study. Temporary shutdown of blood flow in CAs during CEA is accompanied by a significant elevation of S100, NSE concentration with their subsequent restoration (three days after surgery). ROC analysis showed that none of the methods for CIT assessment (SP, rSO2 and ∆rSO2) was a valuable predictor of cerebral damage during CEA. Conclusion SP with a threshold value of ≤40 mmHg has an average quality of prediction (AUC = 63). ∆rSO2 of ≥20% and a threshold value of rSO2 ≤ 40% have an unsatisfactory quality of prediction (AUC < 60).

The impact of posture on the cardiac depolarization and repolarization phases of the QT interval in healthy subjects.

BACKGROUND: Postural changes affect both heart rate and the QT interval. OBJECTIVE: To investigate the effects of postural changes on the depolarization and repolarization phases of the QT interval. METHODS: A three lead ECG from 12 healthy young volunteers was recorded in the standing, sitting and in the supine positions. For the purpose of this study, we defined the depolarization phase as the QRS complex plus the ST segment and the repolarization phase as the duration of the T wave. RESULTS: QTc did not change with changes in position. The ratio of the duration of the depolarization phase to the repolarization phase was higher in the supine position (0.98±0.13) compared to the standing position (0.83±0.17). CONCLUSIONS: The origin of the T wave moves closer to the QRS complex during standing compared to the supine position. The observed changes are mainly due to shortening of the ST segment during standing compared to supine position.

Concomitant ablation for non-paroxysmal atrial fibrillation: combined energy versus cryoablation alone.

Background: Surgical ablation of atrial fibrillation has been the most efficient treatment for atrial fibrillation (AF). Combined energy (CE) ablation and cryoablation alone (CA) are the most common energy modes used for ablation, however, comparative data is lacking. Objectives: To compare the efficacy of CE ablation with CA in the setting of concomitant biatrial ablation for non-paroxysmal AF. Methods: A retrospective analysis of 453 patients with non-paroxysmal AF undergone concomitant biatrial ablation from November 2007 to December 2022 during elective cardiac surgery using either combined bipolar radiofrequency with cryoenergy or cryoenergy alone was performed. Propensity score matching was conducted to balance the covariates in the groups. Results: There were 157 patients per group after matching. CE ablation was associated with lower odds of atrial tachyarrhythmia recurrence (OR = 0.13, 95% CI 0.02-0.91, p = 0.040), a significantly lower rate of hospital readmissions due to rhythm disruption (HR = 0.34, 95% CI 0.18-0.65, p < 0.001), and lower cumulative incidence of stroke (SHR = 0.38, 95% CI 0.15-0.97, p = 0.043). No significant difference in permanent pacemaker implantation was observed between the two groups. Conclusions: In the setting of concomitant biatrial ablation for non-paroxysmal AF, combined bipolar radiofrequency and cryoablation appear to be a superior treatment modality compared to cryoablation alone in achieving long-term freedom from atrial arrhythmias, in reducing arrhythmia-related hospital readmissions and ischemic strokes.

Locus-Specific Bisulfate NGS Sequencing of GSTP1, RNF219, and KIAA1539 Genes in the Total Pool of Cell-Free and Cell-Surface-Bound DNA in Prostate Cancer: A Novel Approach for Prostate Cancer Diagnostics.

The locus-specific methylation of three genes (GSTP1, RNF219, and KIAA1539, also known as FAM214B) in the total pool of blood cell-free DNA, including cell-free DNA from plasma and cell-surface-bound DNA, of patients with prostate cancer and healthy donors was studied on the MiSeq platform. Our study found a higher methylation index of loci for total cell-free DNA compared with cell-free DNA. For total cell-free DNA, the methylation of GSTP1 in each of the 11 positions provided a complete separation of cancer patients from healthy donors, whereas for cell-free DNA, there were no positions in the three genes allowing for such separation. Among the prostate cancer patients, the minimum proportion of GSTP1 genes methylated in any of the 17 positions was 12.1% of the total circulated DNA fragments, and the minimum proportion of GSTP1 genes methylated in any of the 11 diagnostically specific positions was 8.4%. Total cell-free DNA was shown to be more convenient and informative as a source of methylated DNA molecules circulating in the blood than cell-free DNA.

Selection of reference genes for quantitative analysis of microRNA expression in three different types of cancer.

MicroRNAs (miRNAs) are promising biomarkers in cancer research. Quantitative PCR (qPCR), also known as real-time PCR, is the most frequently used technique for measuring miRNA expression levels. The use of this technique, however, requires that expression data be normalized against reference genes. The problem is that a universal internal control for quantitative analysis of miRNA expression by qPCR has yet to be known. The aim of this work was to find the miRNAs with stable expression in the thyroid gland, brain and bone marrow according to NanoString nCounter miRNA quantification data. As a results, the most stably expressed miRNAs were as follows: miR-361-3p, -151a-3p and -29b-3p in the thyroid gland; miR-15a-5p, -194-5p and -532-5p in the brain; miR-140-5p, -148b-3p and -362-5p in bone marrow; and miR-423-5p, -28-5p and -532-5p, no matter what tissue type. These miRNAs represent promising reference genes for miRNA quantification by qPCR.

Locus-Specific Methylation of GSTP1, RNF219, and KIAA1539 Genes with Single Molecule Resolution in Cell-Free DNA from Healthy Donors and Prostate Tumor Patients: Application in Diagnostics.

The locus-specific methylation of three genes (GSTP1, RNF219, and KIAA1539 (also known as FAM214B)) in the blood plasma cell-free DNA (cfDNA) of 20 patients with prostate cancer (PCa), 18 healthy donors (HDs), and 17 patients with benign prostatic hyperplasia (BPH) was studied via the MiSeq platform. The methylation status of two CpGs within the same loci were used as the diagnostic feature for discriminating the patient groups. Many variables had good diagnostic characteristics, e.g., each of the variables GSTP1.C3.C9, GSTP1.C9, and GSTP1.C9.T17 demonstrated an 80% sensitivity at a 100% specificity for PCa patients vs. the others comparison. The analysis of RNF219 gene loci methylation allowed discriminating BPH patients with absolute sensitivity and specificity. The data on the methylation of the genes GSTP1 and RNF219 allowed discriminating PCa patients, as well as HDs, with absolute sensitivity and specificity. Thus, the data on the locus-specific methylation of cfDNA (with single-molecule resolution) combined with a diagnostic approach considering the simultaneous methylation of several CpGs in one locus enabled the discrimination of HD, BPH, and PCa patients.

Results from an enhanced recovery program for cardiac surgery.

OBJECTIVE: Enhanced recovery programs are multidisciplinary perioperative bundles of evidence-based process measures. Following the design and implementation of preanesthesia and intraoperative enhanced recovery programs for cardiac surgery guidelines, we evaluated the association between compliance and key clinical outcomes. METHODS: Consecutive patients undergoing cardiac surgery at a single tertiary medical center from September 2017 to June 2018 were included. Patients were stratified into low (0-4 measures) and high (5-7 measures) compliance groups and then 1-to-3 propensity matched on the basis of 15 patient and surgical covariables. The primary outcome of interest was time to postoperative extubation. Secondary outcomes included interval time point extubation rates and intensive care unit, floor, and hospital lengths of stay. RESULTS: A total of 451 patients were included in the study. After propensity matching (n = 315), patients in the high compliance group (n = 84) had a significant reduction in time to extubation (P < .001), floor length of stay (P = .01), and hospital length of stay (P = .03) compared with patients in the low compliance group (n = 231). Patients in the high compliance group were more likely to be extubated in the operating room (odds ratio, 35.8; 95% confidence interval, 10.66-168.75; P < .001) and within 6 hours of surgery (odds ratio, 2.6; 95% confidence interval, 1.18-6.07; P < .02). High compliance was associated with a median estimated time reduction of 3.4 hours to postoperative extubation (P < .001) and 19.4 hours in hospital length of stay (P = .01) compared with low compliance counterparts. There were no reintubations reported among patients extubated in the operating room (0/62 patients). CONCLUSIONS: There is value in developing phase-specific enhanced recovery programs guidelines, which improve rates of early extubation and affect the duration of stay after cardiac surgery. These results are hypothesis generating, and further prospective study is necessary to identify clinical impact of further program expansion.

Profiling 25 Bone Marrow microRNAs in Acute Leukemias and Secondary Nonleukemic Hematopoietic Conditions.

INTRODUCTION: The standard treatment of acute leukemias (AL) is becoming more efficacious and more selective toward the mechanisms via which to suppress hematologic cancers. This tendency in hematology imposes additional requirements on the identification of molecular-genetic features of tumor clones. MicroRNA (miRNA, miR) expression levels correlate with cytogenetic and molecular subtypes of acute leukemias recognized by classification systems. The aim of this work is analyzing the miRNA expression profiles in acute myeloblastic leukemia (AML) and acute lymphoblastic leukemia (ALL) and hematopoietic conditions induced by non-tumor pathologies (NTP). METHODS: A total of 114 cytological samples obtained by sternal puncture and aspiration biopsy of bone marrow (22 ALLs, 44 AMLs, and 48 NTPs) were analyzed by real-time PCR regarding preselected 25 miRNAs. For the classification of the samples, logistic regression was used with balancing of comparison group weights. RESULTS: Our results indicated potential feasibility of (i) differentiating ALL+AML from a nontumor hematopoietic pathology with 93% sensitivity and 92% specificity using miR-150:miR-21, miR-20a:miR-221, and miR-24:nf3 (where nf3 is a normalization factor calculated from threshold cycle values of miR-103a, miR-191, and miR-378); (ii) diagnosing ALL with 81% sensitivity and 81% specificity using miR-181b:miR-100, miR-223:miR-124, and miR-24:nf3; and (iii) diagnosing AML with 81% sensitivity and 84% specificity using miR-150:miR-221, miR-100:miR-24, and miR-181a:miR-191. CONCLUSION: The results presented herein allow the miRNA expression profile to de used for differentiation between AL and NTP, no matter what AL subtype.

Difference between ejection times measured at two different peripheral locations as a novel marker of vascular stiffness.

Pulse wave velocity (PWV) has been recommended as an arterial damage assessment tool and a surrogate of arterial stiffness. However, the current technology does not allow to measure PWV both continuously and in real-time. We reported previously that peripherally measured ejection time (ET) overestimates ET measured centrally. This difference in ET is associated with the inherent vascular properties of the vessel. In the current study we examined ETs derived from plethysmography simultaneously at different peripheral locations and examined the influence of the underlying arterial properties on ET prolongation by changing the subject's position. We calculated the ET difference between two peripheral locations (ΔET) and its corresponding PWV for the same heartbeat. The ΔET increased with a corresponding decrease in PWV. The difference between ΔET in the supine and standing (which we call ET index) was higher in young subjects with low mean arterial pressure and low PWV. These results suggest that the difference in ET between two peripheral locations in the supine vs standing positions represents the underlying vascular properties. We propose ΔET in the supine position as a potential novel real-time continuous and non-invasive parameter of vascular properties, and the ET index as a potential non-invasive parameter of vascular reactivity.

A Pulse Wave Velocity Based Method to Assess the Mean Arterial Blood Pressure Limits of Autoregulation in Peripheral Arteries.

Background: Constant blood flow despite changes in blood pressure, a phenomenon called autoregulation, has been demonstrated for various organ systems. We hypothesized that by changing hydrostatic pressures in peripheral arteries, we can establish these limits of autoregulation in peripheral arteries based on local pulse wave velocity (PWV). Methods: Electrocardiogram and plethysmograph waveforms were recorded at the left and right index fingers in 18 healthy volunteers. Each subject changed their left arm position, keeping the right arm stationary. Pulse arrival times (PAT) at both fingers were measured and used to calculate PWV. We calculated ΔPAT (ΔPWV), the differences between the left and right PATs (PWVs), and compared them to the respective calculated blood pressure at the left index fingertip to derive the limits of autoregulation. Results: ΔPAT decreased and ΔPWV increased exponentially at low blood pressures in the fingertip up to a blood pressure of 70 mmHg, after which changes in ΔPAT and ΔPWV were minimal. The empirically chosen 20 mmHg window (75-95 mmHg) was confirmed to be within the autoregulatory limit (slope = 0.097, p = 0.56). ΔPAT and ΔPWV within a 20 mmHg moving window were not significantly different from the respective data points within the control 75-95 mmHg window when the pressure at the fingertip was between 56 and 110 mmHg for ΔPAT and between 57 and 112 mmHg for ΔPWV. Conclusions: Changes in hydrostatic pressure due to changes in arm position significantly affect peripheral arterial stiffness as assessed by ΔPAT and ΔPWV, allowing us to estimate peripheral autoregulation limits based on PWV.