Presentation on theme: "A Novel Score to Estimate the Risk of Pneumonia After Cardiac Surgery"— Presentation transcript:
1 A Novel Score to Estimate the Risk of Pneumonia After Cardiac Surgery Arman Kilic, MD1, Rika Ohkuma, MD 1, J. Trent Magruder, MD1, Joshua C. Grimm, MD1, Marc Sussman, MD1,Eric B. Schneider, PhD1, Glenn J.R. Whitman, MD11Division of Cardiac Surgery, Johns Hopkins Hospital, Baltimore, MDNone of the authors have any relevant financial relationships to disclose.
2 BackgroundPneumonia is the most common nosocomial infection after cardiac surgeryPostoperative pneumonia is associated with increased risk of mortality and readmission, as well as prolonged ICU and hospital stay and increased costs of careA composite risk index for estimating pneumonia risk after cardiac surgery would have clinical utility
3 Study AimTo derive and validate a risk score for postoperative pneumonia after cardiac surgery
4 Study Design Data Source Single institution series Study Population Adult patients (18 or older)Study period: January 1, 2005 to December 31, 2012Excluded: ECMO or heart transplant patients
5 Data Analysis Primary Outcome Postoperative pneumonia – STS definition – “positive sputum cultures, transtracheal fluid, bronchial washings, and/or clinical findings consistent with pneumonia”Study PopulationRandomly divided 3:1 into training and validation sets
6 Data Analysis Generation of Risk Score in the Training Set Univariable logistic regression analysis to evaluate association between multiple preoperative and intraoperative variables and postoperative pneumoniaVariables associated with pneumonia in univariable analysis (p<0.20) and <10% missing data entered into a multivariable modelPoints were assigned to significant risk factors based on the relative magnitudes of the odds ratios.
7 Data Analysis Validation of Risk Score in the Validation Set Predictive accuracy of the risk score evaluated using logistic regression, area under receiver operating characteristic curve (c-index)C-indices also compared between risk score and STS prolonged ventilation model in predicting pneumonia.
10 Results Postoperative pneumonia rate of 4.5% (n=282) In-hospital mortality rate15.3% (pneumonia) versus 4.8% (no pneumonia)p<0.00130-day mortality rate8.0% (pneumonia) versus 4.6% (no pneumonia)p=0.01.
11 Multivariable Model for Pneumonia CovariateOdds Ratio (95% Confidence Interval)P-valuePoints AssignedAge ≥ 65 Years1.40 ( )0.043Chronic Lung DiseaseNoneMildModerateSevereReference1.97 ( )3.07 ( )3.31 ( )0.005<0.0010.002467Peripheral Vascular Disease1.69 ( )0.01Cardiopulmonary Bypass Time >100 Minutes1.71 ( )Intraoperative Red Blood Cell Transfusion1.08 ( )2Pre- or Intraoperative Intra-Aortic Balloon Pump2.01 ( )TOTAL POINTS POSSIBLE-22*other variables included in the multivariable model but not significant predictors:hypertension, prior cardiac intervention, myocardial infarction in last 24 hours, cardiogenic shock, increasing serum creatinine, emergent operation, type of operation, increasing aortic cross clamp time, and tricuspid valve procedure
12 Probability of Pneumonia Based on the Training Set
13 Probability of Pneumonia Based on the Training Set Predicted Rate95% CI for Predicted Rate
14 Probability of Pneumonia Based on the Training Set Predicted Rate95% CI for Predicted RateScore=0Rate=1.2%
15 Probability of Pneumonia Based on the Training Set Score=22Rate=55%Predicted Rate95% CI for Predicted RateScore=0Rate=1.2%
16 Predicted Rates of Pneumonia in the Training Set by Score Categories
17 Actual Rates of Pneumonia in the Validation Set by Score Categories
18 Correlation Between Predicted and Actual Rates of Pneumonia Correlation between predicted rates in training set and actual rates in validation setr= p<0.001
19 Predictive Accuracy of the Risk Score in the Validation Set Logistic regressionOdds ratio 1.32, 95% CIp<0.001C-index0.74 (risk score) versus 0.71 (STS prolonged ventilation model) in predicting postoperative pneumonia.
20 Summary Component Points Age ≥ 65 years 3 Chronic Lung Disease None MildModerateSevere467Peripheral Vascular DiseaseCardiopulmonary Bypass Time >100 MinutesIntraoperative Red Blood Cell Transfusion2Pre- or Intraoperative Intra-Aortic Balloon PumpTOTAL POINTS POSSIBLE22
21 Limitations Clinical diagnosis of pneumonia can be subjective In-hospital pneumonia diagnoses onlyPotential for other risk factors not captured in our analysisDid not account for interrelationship between pneumonia and other postoperative complications
22 ConclusionsWe derived and validated a risk score for postoperative pneumonia in adult patients undergoing cardiac surgeryImmediately applicable on ICU arrivalRisk score may aid in identifying high risk patients, and therefore have applications in:clinical research stratificationtargeting patients who will benefit from tailored preoperative management
23 A Novel Score to Estimate the Risk of Pneumonia After Cardiac Surgery Arman Kilic, MD1, Rika Ohkuma, MD 1, Joshua C. Grimm, MD1,J. Trent Magruder, MD1, Marc Sussman, MD1,Eric B. Schneider, PhD1, Glenn J.R. Whitman, MD11Division of Cardiac Surgery, Johns Hopkins Hospital, Baltimore, MD