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- Kristenson, Karolina, et al.
(author)
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Peak oxygen uptake in combination with ventilatory efficiency improve risk stratification in major abdominal surgery
- 2024
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In: Physiological Reports. - : WILEY. - 2051-817X. ; 12:1
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Journal article (peer-reviewed)abstract
- This pilot study aimed to evaluate if peak VO2 and ventilatory efficiency in combination would improve preoperative risk stratification beyond only relying on peak VO2. This was a single-center retrospective cohort study including all patients who underwent cardiopulmonary exercise testing (CPET) as part of preoperative risk evaluation before major upper abdominal surgery during years 2008-2021. The primary outcome was any major cardiopulmonary complication during hospitalization. Forty-nine patients had a preoperative CPET before decision to pursue to surgery (cancer in esophagus [n = 18], stomach [6], pancreas [16], or liver [9]). Twenty-five were selected for operation. Patients who suffered any major cardiopulmonary complication had lower ventilatory efficiency (i.e., higher VE/VCO2 slope, 37.3 vs. 29.7, p = 0.031) compared to those without complications. In patients with a low aerobic capacity (i.e., peak VO2 < 20 mL/kg/min) and a VE/VCO2 slope >= 39, 80% developed a major cardiopulmonary complication. In this pilot study of patients with preoperative CPET before major upper abdominal surgery, patients who experienced a major cardiopulmonary complication had significantly lower ventilatory efficiency compared to those who did not. A low aerobic capacity in combination with low ventilatory efficiency was associated with a very high risk (80%) of having a major cardiopulmonary complication.
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| 2. |
- Kristenson, Karolina, et al.
(author)
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VE/VCO2 slope threshold optimization for preoperative evaluation in lung cancer surgery: identifying true high- and low-risk groups
- 2024
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In: Journal of Thoracic Disease. - : AME PUBLISHING COMPANY. - 2072-1439 .- 2077-6624. ; 16:1, s. 123-132
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Journal article (peer-reviewed)abstract
- Background: Cardiopulmonary exercise testing (CPET) enables measurement of the slope of the increase in minute ventilation in relation to carbon dioxide elimination during exercise (the VE/VCO2 slope). Several studies have shown that the VE/VCO2 slope is a strong marker for postoperative complications and mortality. However, current thresholds for adverse outcomes are generated from historical data in heart failure patients.Methods: This was a retrospective analysis of 158 patients with lung cancer who underwent lobectomy or pneumonectomy during 2008–2020. The main outcome was major pulmonary complications (MPC) or death ≤30 days of cancer surgery. Patients were first categorized using two different single threshold approaches; the traditional threshold of 35 and the highest Youden value from the receiver operating curve (ROC) analysis. Secondly, patients were categorized into three risk groups using two thresholds. These two thresholds were determined in an ROC analysis, where the VE/VCO2 slope values generating either a 90% sensitivity (lower threshold) or a 90% specificity (upper threshold) for the main outcome were chosen. The frequency of complications was compared using Chi2. The overall model quality was evaluated by an area under the curve (AUC) analysis. Positive predictive values (PPVs) and negative predictive values (NPVs) are presented.Results: The two thresholds, <30 (90% sensitivity) and >41 (90% specificity), created three risk groups: low risk (VE/VCO2 slope <30, n=44, 28%); intermediate risk (VE/VCO2 slope 30–41, n=95, 60%) and high risk (VE/VCO2 slope >41, n=19, 12%). The frequency of complications differed between groups: 5%, 16% and 47% (P<0.001). Using two thresholds compared to one threshold increased the overall model quality (reaching AUC 0.70, 95% confidence interval: 0.59–0.81), and identified a high sensitivity threshold (VE/VCO2 slope <30) which generated a NPV of 95% but importantly, also a high specificity threshold (VE/VCO2 slope >41) with a PPV of 47%.Conclusions: Risk stratification based on three risk groups from the preoperative VE/VCO2 slope increased the model quality, was more discriminative and generated better PPV and NPV compared to traditional risk stratification into two risk groups.
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| 3. |
- Kristenson, Karolina, 1984-, et al.
(author)
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Ventilatory efficiency in combination with peak oxygen uptake improves risk stratification in patients undergoing lobectomy
- 2022
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In: JTCVS Open. - : Elsevier. - 2666-2736. ; 11:C, s. 317-326
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Journal article (peer-reviewed)abstract
- Objective: We aimed to evaluate whether or not using the slope of the increase in minute ventilation in relation to carbon dioxide (VE/VCO2-slope), with a cutoff value of 35, could improve risk stratification for major pulmonary complications or death following lobectomy in lung cancer patients at moderate risk (VO2peak = 10-20 mL/kg/min). Methods: Single center, retrospective analysis of 146 patients with lung cancer who underwent lobectomy and preoperative cardiopulmonary exercise testing in 2008-2020. The main outcome was any major pulmonary complication or death within 30 days of surgery. Patients were categorized based on their preoperative cardiopulmonary exercise testing as: low-risk group, peak oxygen uptake >20 mL/kg/min; low-moderate risk, peak oxygen uptake 10 to 20 mL/kg/min and VE/VCO2-slope <35; and moderate-high risk, peak oxygen uptake 10 to 20 mL/kg/min and VE/VCO2-slope =35. The frequency of complications between groups was compared using ?2 test. Logistic regression was used to calculate the odds ratio with 95% CI for the main outcome based on the cardiopulmonary exercise testing group. Results: Overall, 25 patients (17%) experienced a major pulmonary complication or died (2 deaths). The frequency of complications differed between the cardiopulmonary exercise testing groups: 29%, 13%, and 8% in the moderate-high, low-moderate, and low-risk group, respectively (P = .023). Using the low-risk group as reference, the adjusted odds ratio for the low-moderate risk group was 3.44 (95% CI, 0.66-17.90), whereas the odds ratio for the moderate-high risk group was 8.87 (95% CI, 1.86-42.39). Conclusions: Using the VE/VCO2-slope with a cutoff value of 35 improved risk stratification for major pulmonary complications following lobectomy in lung cancer patients with moderate risk based on a peak oxygen uptake of 10 to 20 mL/kg/min. This suggests that the VE/VCO2-slope can be used for preoperative risk evaluation in lung cancer lobectomy. © 2022 The Author(s)
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