Association between preoperative blood pressure and outcomes in cardiac surgery: results of a prospectively planned cohort study.

BACKGROUND: It is unknown whether unwitnessed BP (UBP) measurement or ambulatory BP (ABP) monitoring improves the prediction of adverse events estimated by risk scores. We intended to study associations between preoperative BP measured through these two methods and the incidence of adverse outcomes in patients undergoing cardiac surgery. METHODS: We included a cohort of 167 patients undergoing elective or urgent cardiac surgeries. Preoperative BP was measured by UBP and 24-hour ABP. Primary outcome was the combination of mortality from any cause, nonfatal myocardial infarction, nonfatal stroke, new hospital admission, and dialysis occurring within 30 days after surgery. The associations between preoperative BP and surgical outcomes were tested using the Chi-square test and Analysis of Variance. A generalized linear model with a logistic link function and a robust estimator was used to adjust for the EuroScore-II risk estimation. RESULTS: The incidence of the primary outcome increased in parallel with the quartiles of the 24-hour ABP in participants submitted to CABG: 10% in the first quartile, 13% in the second, 37% in the third, and 53% in the fourth quartile (P for trend<0.01). Quartiles of overnight ABP were also significantly associated with postoperative complications in patients undergoing CABG (P=0.04). The risks in CABG patients were independent of the EuroScore-II. There was no association between BP and outcomes in patients submitted to other surgeries. CONCLUSIONS: High preoperative BP measured by ABP monitoring is a risk factor for postoperative complications in patients submitted to CABG.

Diagnosis of obstructive sleep apnea syndrome and its outcomes with home portable monitoring.

BACKGROUND: The use of portable respiratory monitoring (PM) has been proposed for the diagnosis of obstructive sleep apnea syndrome (OSAS), but most studies that validate PM accuracy have not followed the best standards for diagnostic test validation. The objective of the present study was to evaluate the accuracy of PM performed at home to diagnose OSAS and its outcomes after first validating PM in the laboratory setting by comparing it to polysomnography (PSG). METHODS: Patients with suspected OSAS were submitted, in random order, to PM at the sleep laboratory concurrently with PSG (lab-PM) or at home-PM. The diagnostic performance was assessed by sensitivity, specificity, positive and negative predictive values, positive likelihood ratio (+LR), negative likelihood ratio (-LR), intraclass correlation coefficients, kappa statistic, and Bland-Altman plot. RESULTS: One hundred fifty-seven subjects (73% men, mean age +/- SD, 45 +/- 12 yr) with an apnea-hypopnea index (AHI) of 31 (SD +/- 29) events/h were studied. Excluding inadequate recordings, 149 valid comparisons with lab-PM and 121 with unattended home-PM were obtained. Compared to PSG for detecting AHI > 5, the lab-PM demonstrated sensitivity of 95.3%, specificity of 75%, +LR of 3.8, and -LR of 0.11; the home-PM exhibited sensitivity of 96%, specificity of 64%, +LR of 2.7, and -LR of 0.05. Kappa statistics indicated substantial correlation between PSG and PM results. Bland-Altman plot showed smaller dispersion for lab-PM than for home-PM. Pearson product moment correlation coefficients among the three AHIs and clinical outcomes were similar, denoting comparable diagnostic ability. CONCLUSIONS: This study used all available comparison methods to demonstrate accuracy of PM in-home recordings similar to that of repeated PSGs. PM increases the possibility of correctly diagnosing and effectively treating OSAS in populations worldwide.