SESSION TITLE: Cardiovascular Disease Posters I
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: The heart failure (HF) syndrome includes global and cerebral hypoperfusion. We reported that HF patients have low resting cerebral oxygen saturation (SctO2) and have a decline in SctO2 approaching the anaerobic threshold (AT). We sought to study peripheral (SpO2) and cerebral (SctO2) changes in oxygenation at rest and during 6 minute walk (6MW) and to study the impact of oxygen supplementation.
METHODS: We conducted a prospective cohort study in 30 patients with HF with 21 patients being male, average age of 66 and average HF duration of 48 months. LVEF ranged from 12-60% (32.1%) with only 4 pts > 55%. Average BNP was 353 pg/ml. During a non-urgent visit to our HF clinic, patients performed a 6MW without additional oxygen followed by a second 6MW with oxygen (3L/min nasal cannula) within 60 minutes or starting the 6MW with oxygen followed by a second 6MW without oxygen within 60 minutes. SctO2 and SpO2 were continuously monitored.
RESULTS: 30 patients safely completed both 6MW. Walk distances with or without supplemental oxygen (785 vs 814 feet, respectively) were not significantly different. Similarly, SpO2-rest (96.7% vs 97.9%), SpO2-6min (95.2% vs 95.5%), SctO2-rest (64.5% vs 62.7%) or SctO2-6 min (62.3 vs 61.3) did not significantly differ either with or without supplemental O2, respectively.
CONCLUSIONS: During 6MW in HF patients, oxygen supplementation did not alter walk distances, baseline or post walk SpO2 or SctO2, nor modest exercise declines observed in SpO2 and SctO2. This study underscores the complexity of peripheral/cerebral oxygen delivery in HF patients. It also suggests that 6MW, even in symptomatic HF patients, may not approximate AT in most patients. Given concern that repetitive episodes of cerebral hypoxia may contribute to cognitive dysfunction, a better understanding of this physiology is needed.
CLINICAL IMPLICATIONS: Both peripheral (SpO2) and cerebral (SctO2) oxygenation are important biomarkers in HF patients. We have observed abnormal SctO2, despite normal SpO2, in HF patients that decline at AT. The current study demonstrated the lack of these observations with 6MW and the lack of effect of oxygen supplementation.
DISCLOSURE: The following authors have nothing to disclose: Jeffrey Ziffra, Hesam Keshmiri, Luay Rifai, Tariq Yousuf, Jalal Vargha, Marc Silver
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