The impact of reduced left ventricular contractility on retinal perfusion

Abstract

Purpose : To show the relationship between left ventricular contractility (LVc) and retinal blood flow (Q), including the influence of intraocular pressure (IOP).

Methods : A mathematical model of retinal circulation was developed to predict alterations in total Q associated with reductions in LVc and categorized levels of IOP. The model simulates blood flow in the retinal circulation as an electric circuit where the current flows through a network of capacitance and resistances. Variable resistances represent passive diameter changes due to the level of IOP. Q is driven by systemic pressures computed using a mathematical model of cardiovascular physiology that simulates reductions in LVc, as previously validated in a preclinical model of myocardial infarction. Alterations of LVc by 10%, 30%, and 50% for IOP levels of 15, 20, 25, and 30 mmHg were considered.

Results : Model simulations indicate that Q decreased as LVc is reduced for all IOP levels (Table1). At IOP 15mmHg, reducing LVc by 50% from baseline induced a change in Q from 6.57 to 5.45 10^-4 cm³/s (17%). At IOP 25mmHg, LVc reduction of 50% induced a 30% decrease in Q (Figure B). Simulations indicate that the LVc-induced reduction of blood supply to the retina is more pronounced at higher IOP levels. The effect of LVc reduction on blood flow can be comparable to that expected in ocular hypertensive eyes with normal LVc (Figure A). For IOP 15mmHg and LVc reduced by 50%, Q is predicted to be 5.45 10^-4 cm³/s, lower than the value predicted for IOP 25mmHg and baseline LVc.

Conclusions : Model simulations suggest that LVc reductions decrease blood flow to the retina and pose a risk to retinal perfusion similar to ocular hypertension. In addition, these changes are more pronounced for elevated levels of IOP, suggesting a strong relationship between systolic cardiac function and retinal blood flow. This finding is likely to be of clinical importance as it may allow for ongoing monitoring of cardiac function.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.