Sinusoidal changes in transcutaneous oxygen pressure, suggesting Cheyne-Stokes respiration, are frequent and of poor prognosis among patients with suspected critical limb ischemia

Background and aims: Transcutaneous oxygen pressure (TcpO(2)) is used in patients with suspected critical limb ischemia (CLI). Sinusoidal changes (SC-) in TcpO(2) are found in patients with Cheyne-Stokes respiration (CSR). We aimed to determine the characteristics of TcpO(2) changes at rest in patients with suspected CLI, define the objective criteria for SC similar to TcpO(2) patterns (SC+), and estimate the prevalence of SC+ in our population and its impact on the outcome. Methods: We retrospectively analyzed 300 chest TcpO(2) recordings performed in a 16-month period. We determined the presence/absence of SC similar to TcpO(2) by visual analysis. We determined the acceptable error in the regularity of peaks of the cross-correlation with ROC curve analysis, among patients with typical SC similar to TcpO(2) and non-sinusoidal patterns. Then, we defined SC + as a minimum of five peaks, a standard deviation of TcpO(2) 1.25 mmHg, an error in regularity of peaks of the cross-correlation < 10%, and a cycle length between 30 and 100 s. In patients included until October 2019, we compared the outcome as a function of SC + or SC with Cox models. Results: Mathematical detection of SC + found that 43 patients (14.3%) fulfilled all four defined criteria at the chest level, but only 23 did so at the limb level. In the follow-up of 207 patients, the presence of Sc similar to TcpO(2) at the chest significantly increased the risk of mortality: hazard ratio: 2.69 [95%CI: 1.37-5.30]; p < 0.005. Conclusions: SC similar to TcpO(2) is frequent, and is associated with a poor outcome in patients with suspected CLI.

Automated summary

In this study, sinusoidal changes similar to TcpO(2) were found to be common in patients with suspected CLI and were associated with poor outcomes. The prevalence of limb SC+ in suspected CLI patients was lower compared to chest level. The presence of chest SC similar to TcpO(2) significantly increased the risk of mortality in follow-up of patients.