4th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV 22-25 September 2002, San Diego, CA, USA

A COMPARISON OF CARDIAC OUTPUT AND ARTERIOVENOUS OXYGEN DIFFERENCE IN INDIVIDUALS WITH HIV TAKING AND NOT TAKING HIGHLY ACTIVE ANTIRETROVIRAL THERAPY

Antiviral Therapy 2002; 7:L10 (abstract 16)

WT Cade¹, LE Fantry¹, SR Nabar¹, DK Shaw² and RE Keyser^1
1Departments of Physical Therapy and Internal Medicine, School of Medicine, University of Maryland, Baltimore, Md., USA; ²Department of Physical Education, Southwest Texas State University, San Marcos, Tex., USA

AIM: The aim of this study was to compare central oxygen delivery [cardiac output (Qt)] and peripheral oxygen extraction-utilization [arteriovenous oxygen difference (a-vO₂)] in groups of individuals with HIV taking and not taking highly active antiretroviral therapy (HAART).

METHODS: Fifteen subjects (6 female and 9 male) infected with HIV taking highly active antiretroviral therapy (HAART), 15 subjects infected with HIV not taking HAART and 15 healthy gender and activity level-matched non-HIV-infected controls (n=45) performed an incremental maximal exercise treadmill test to exhaustion. Continuous ECG and metabolic data were recorded. Non-invasive Qt was measured at each stage and at peak exercise. A-vO₂ was determined by rearrangement of the indirect Fick equation. Variance in peak metabolic intensity was secondarily adjusted for using analysis of covariance (ANCOVA).

RESULTS: Peak a-vO₂ was significantly lower (P<0.05) in subjects with HIV taking HAART (10.0 ±0.5 volume%) compared with subjects with HIV not taking HAART (11.7 ±0.5 volume%) and non-infected controls (12.7 ±0.5 volume%). In subjects with HIV taking HAART, peak heart rate (170.5 ±3.9 bpm) was lower (P<0.05) and stroke volume (123.0 ±3.9 ml/beat) at peak exercise was higher (P<0.05) than subjects with HIV not taking HAART (179.9 ±3.5 bpm) (106.6 ±3.9 ml/beat) and non-infected controls (185.4 ±3.8 bpm; 100.6± 4.0 ml/beat). There were no significant differences in peak Qt between groups.

CONCLUSIONS: Peak a-vO₂ was diminished in subjects infected with HIV taking HAART compared with HIV-infected subjects not taking HAART and noninfected controls matched for age, gender and physical activity level. Findings of the current study implicated HAART as a primary contributor to decreased muscle oxygen extraction-utilization in individuals infected with HIV. Nucleoside analogue medication has been demonstrated to decrease mitochondrial enzyme function. Therefore, the limited ability of the muscles to extract oxygen may have been the result of reduced oxidative enzyme function as opposed to alterations in other factors that determine a-vO₂, such as oxygen convection-diffusion coupling.

Presenting author: WT Cade

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