A feasibility study to evaluate a novel method of assessing microcirculatory function as a predictor of major adverse cardiovascular events

Abstract

Cardiovascular disease (CVD) is a leading cause of mortality and represents a group of disorders including coronary artery disease, cerebrovascular disease, peripheral vascular disease and structural heart disorders. The microcirculation represents the site at which the earliest signs of CVD occur. The conjunctival microcirculation is readily accessible and a few groups have reported the feasibility of assessing conjunctival microcirculatory parameters using a combination of a slit-lamp biomicroscope and digital camera.

The aims of this project were to determine if the conjunctival microcirculation could, be feasibly assessed using a combination of a slit-lamp biomicroscope (TopCon SL-D4) and a smartphone (iPhone 6s) and if this combination could detect differences in microcirculatory parameters between healthy controls and two distinct patient groups with CVD.

Assessment of conjunctival microcirculatory parameters using this novel imaging modality was successfully performed in a group of healthy controls, as described in chapters 2 and 3. Microvessel diameter (D), axial velocity (Va), wall shear rate (WSR) and blood volume flow (Q) represented the measured parameters.

Chapter 4 describes the comparison of 59 patients with acute myocardial infarction (MI) and 56 healthy controls. Significantly lower Va and WSR was found in the MI patients. Q was lower in the MI patients but only for vessels above 16μm.

Chapter 5 describes the comparison of 11 cyanotic congenital heart disease (CCHD) patients and 14 healthy controls. Va and WSR were significantly lower in the CCHD patients and Q was also significantly lower but only in vessels above 22μm.

This thesis reports the feasibility of a smartphone-led assessment of the conjunctival microcirculation while demonstrating differences in microcirculatory parameters between healthy controls and two CVD groups. The clinical application of this imaging modality, requires further study to assess if it can augment CVD screening and/or the assessment of microcirculatory response to specific CVD therapies.

Date of Award	Apr 2020
Original language	English
Supervisor	Andrew Nesbit (Supervisor) & Tara Moore (Supervisor)