Abstract P296: Poor Functional Capacity is Associated With Peripheral Microvascular Dysfunction in Coronary Artery Disease

Abstract

Introduction: Reduced functional capacity, assessed by self-reported Duke Activity Status Index (DASI) is associated with adverse outcomes. Peripheral microvascular dysfunction, measured as reduced digital reactive hyperemia index (RHI) is also associated with adverse events. Whether microvascular dysfunction is related to functional capacity is unknown. Hypothesis: We hypothesized that peripheral microvascular dysfunction is associated with diminished functional capacity. Methods: In 531 patients with stable CAD (age 62±9, 75% male, 30% Black, EF 55±13%) enrolled in the Mental Ischemia Prognosis Study, self-reported functional capacity was assessed with the DASI questionnaire with a score of >25 as the cutoff for normal. Pulsatile arterial tonometry (EndoPat, Itamar Inc.) was used to measure digital RHI during 5 minutes of upper arm occlusion with blood pressure cuff followed by reperfusion. Logistic regression was used to model reduced RHI (<median) as a function of normal vs low DASI score (>25 vs ≤ 25). Results: Median RHI was 2.01 [IQR 1.67, 2.49] while median DASI score was 45 [29,53], equivalent to 8.3 METs. Compared to those with normal DASI score (>25; N=425), subjects with low DASI score (≤25; N=106) had lower RHI (1.88 [1.64, 2.24] vs 2.06 [1.69, 2.54], P=0.048), higher BMI (32±7 kg/m 2 vs 29±5 kg/m 2 , P<0.001), were more likely to be female (48% vs 20%, P<0.001) and Black (42% vs 28%, P=0.005), and more likely to have a history of hypertension (87% vs 75%, P=0.009), diabetes (39% vs 29%, P=0.046), and heart failure (34% vs. 20%, P=0.003). After adjusting for the aforementioned variables in addition to history of dyslipidemia, smoking and prior MI, those with a low DASI score had a significantly higher likelihood of a reduced RHI (<median) (OR 1.72, 95% CI 1.08 - 2.74, P=0.023) Conclusion: Poor functional capacity is independently associated with microvascular dysfunction in patients with stable CAD, and illustrates a potential mechanism by which reduced functional capacity increases cardiovascular risk. Whether improvement in functional capacity by exercise/rehabilitation programs improves microvascular function requires further investigation.