Peripheral arterial disease: A small and large vessel problem

Peripheral arterial pathology and osteoarthritis of the knee: US examination of arterial wall stiffness, thickness, and flow characteristics

Background

Osteoarthritis (OA) is a widespread chronic joint disorder characterized by the degeneration of articular cartilage, extensive bone remodeling, ligamentous fibrosis, and synovial inflammation impacting millions. Shared factors like phenotypic similarities, hypofibrinolysis, and inflammation constitute similarities in pathophysiology and clinical manifestations between OA and peripheral vascular disease (PVD). This study investigated peripheral arterial flow characteristics, vascular wall thickness, and stiffness in knee OA to clarify a potential association with early atherosclerosis.

Methods

The OA cohort consisted of 35 knees with a mean age of 69 years. The control cohort consisted of 58 knees with a mean age of 68 years. Subjects underwent arterial ultrasound scanning of the common femoral, superficial femoral, and popliteal arteries. Data measured included peak systolic volumetric flow, intima-media thickness, systolic and diastolic vessel diameter, and simultaneous EKG and flow curves. Structural and functional vascular data were quantified using the incremental Young's modulus, pulse wave velocity (PWV), and distensibility.

Results

Significantly elevated arterial volumetric flow, measures of arterial stiffness, and intima-media wall thickness were observed in those with OA compared to those without. PWV as calculated by the Bramwell-Hill equation were found to be significantly greater in all three vessels of patients with OA.

Conclusions

This study supports the association between peripheral arterial pathology and knee OA, consistent with shared clinical and phenotypic traits. The observed characteristics of early vascular pathology suggest potential pathophysiologic linkages between OA and PVD. This foundational framework provides avenues for mechanistic studies exploring the relationship between these two disease processes.

Relative Flow Index as a Novel Optical Coherence Tomography Angiography Biomarker in Primary Open Angle Glaucoma

PRCIS

Relative flow indices as novel optical coherence tomography angiography (OCTA) biomarkers demonstrated reduced optic nerve head and peripapillary large vessel and capillary perfusion in primary open angle glaucoma (POAG). Large vessel perfusion correlated with disease severity and progression.

PURPOSE

To introduce relative flow indices as novel OCTA biomarkers and their pathologic insights in POAG.

MATERIALS AND METHODS

This is a retrospective case-control study where 57 POAG and 57 control eyes were included. OCTA 4.5×4.5 mm optic nerve head (ONH) were analyzed using ImageJ 1.53t to calculate global flow indices (GFIs) and relative flow indices (RFIs) for whole image optic nerve head, isolated radial peripapillary capillary plexus, and isolated large vessel angiograms.

RESULTS

Retinal nerve fiber layer thickness (RNFLT), ONH vascular density (VD), except inside disc and large vessel VD, GFIs, and RFIs were lower in POAG than control. There was a positive correlation between RNFLT and both VD and GFIs. Among RFIs, only large vessel RFI (ONHLVRFI) demonstrated a positive correlation with average RNFLT. Linear regression demonstrated a significant positive coefficient for ONHLVRFI with RNFLT as the dependent variable. The area under receiver operating characteristic curve showed diagnostic accuracy ranging fair, good, and excellent for all biomarkers. Inferior RNFLT had the highest area under the curve (0.922) while optic nerve head large vessel density had the lowest (0.523).

CONCLUSIONS

POAG showed structural loss of RNFL neurovascular unit manifesting as positively correlated reduction of VD and RNFLT. Also, POAG had lower global perfusion of the optic nerve head and peripapillary area, resulting in the positively correlated reduction of GFIs and RNFLT. Although RFIs were lower in POAG, only ONHLVRFI demonstrated a positive correlation and regression with RNFLT, implying that large vessel hypoperfusion was associated with POAG severity and progression.