Fluid responsiveness in patients under mechanical ventilation and low tidal volume ventilation through the pulse pressure variation after tidal volume challenge in the post-operative cardiac surgery

Background

It is known that in the immediate postoperative period of cardiac surgery, strict control of hemodynamic variables and blood volume is necessary, since there is an imbalance between oxygen supply and consumption. Thus, the present study seeks to validate methods previously used in different clinical situations to predict fluid responsiveness, in the current scenario of the immediate postoperative period of cardiac surgery.

Purpose

To evaluate the influence of “tidal volume challenge” from 6 ml / kg to 8 ml / kg of the predicted body weight (PBW) in conjunction with the end expiratory occlusion test (EEOT) in the variation of pulse pressure to predict fluid responsiveness in the immediate postoperative period of cardiac surgery.

Methodology

This prospective study included 30 patients after cardiac surgery. Hemodynamic and ventilatory parameters were initially recorded in mechanical ventilation at 6 ml/kg and after tidial volume challenge and with the EEOT at 8 ml/kg of predicted body weight (PBW). After recorded the intervention data, there was a return to ventilation at 6 ml/kg and a saline infusion of 500 ml was performed for 15 minutes. Fluid responsiveness was defined for patients who had an increase of 10% or more in velocity time integral (VTI) by echocardiogram after volume expansion compared to baseline value. Multivariate analysis was used to identify independent predictors of fluid response status. Sensitivity and specificity analyzes were performed to determine the predictive precision of each parameter.

Results

The main result of our study is that, when the tidal volume is increased from 6 to 8 ml/kg of PBW, the relative increase in pulse pressure variation (%ΔPPV6–8) predicts with excellent accuracy responsiveness to fluids with cut-off values of 18.3%, with sensitivity of 92.9% and specificity of 84% (P=0.019). Although changing PPV6, EEOT6 and EEOT8 are not reliable in predicting fluid responsiveness, they still require additional calculations. PPV8 also discriminates between responders and non-responders; however, with sensitivity (78.6%) and specificity (66.6%) when the value found in the PPV8 is up 8.5, but without statistical significance (figure).

Conclusion

The challenge of tidal volume and its influence on the ΔPP variation has excellent accuracy to predict fluid responsiveness in the immediate postoperative period of cardiac surgery. EEOT did not present good accuracy to predict fluid responsiveness in patients in the immediate postoperative period of cardiac surgery.

Funding Acknowledgement

Type of funding sources: None.

Impact of tricuspid repair on surgical death in patients undergoing mitral valve surgery due to rheumatic disease

Introduction

Observational studies differ on the impact of performing tricuspid repair on surgical mortality. Some studies demonstrate increased surgical mortality related to right ventricular failure and circulatory shock, while there are other studies that evidence improvement in quality of life and signs of right heart failure in the long time.

Objective

To evaluate the impact on surgical mortality of concomitant tricuspid annuloplasty in patients undergoing cardiac surgery for rheumatic mitral valve disease, who have moderate to severe tricuspid regurgitation.

Methods

This is a prospective cohort from January 1, 2017 to December 30, 2020. All patients over 18 years of age who underwent cardiac surgery to correct rheumatic mitral valve disease with moderate to significant tricuspid regurgitation were included. The primary outcome was 30-days mortality.

Results

165 patients were included, 98 (59.4%) underwent tricuspid valve annuloplasty. The mean age was 46, 5 (±12) years, the median of Euroscore II was 2,33%. The 30-days mortality was 17 (10.3%) and there was no difference between the groups submitted or not to tricuspid repair: 12 (12.2%) versus 5 (7.5%); p=0.44, respectively. In the multivariate analysis involving seven variables with a potential prediction of death in 30 days, tricuspid repair had no association with death, RR 2,4 (0,5 – 8,3); p=0.27.

Conclusion

In patients with rheumatic heart disease undergoing cardiac surgery for rheumatic mitral valve disease, perform tricuspid annuloplasty in individuals who had moderate to severe tricuspid insufficiency was not associated with increased surgical mortality.

Funding Acknowledgement

Type of funding sources: None.

P1835Application of SYNTAX score I, II and residual SYNTAX as predictors of long-term clinical outcomes after coronary artery bypass grafting

Background

The evaluation of coronary disease by SYNTAX score I (SSI) is used to grade coronary complexity. Following SSI, two other scores were developed: SYNTAX score II (SSII) and residual SYNTAX score (rSS). Nevertheless, there is still a lack of evidence about the prognostic significance of these scores among patients undergoing CABG.

Purpose

Our aim was to evaluate the relation of the SSI, SSII and rSS score with outcomes in a long-term follow-up after elective CABG.

Methods

This is a single center, registry-based study. Baseline SSI was calculated from patients undergoing CABG by interventional cardiologists. SSI results were considered as usual: <23, 23–32 and >32. SSII and rSRR were then calculated and categorized in tertiles: <21.4, 21.4–29.4 and >29.4 for SSII and 0, 1–5 and >5 for rSS. Primary outcome was a composite of overall death, myocardial infarction, additional revascularization, or stroke (MACCE).

Results

Data were obtained from 559 patients. Median follow-up was 6 years (IQR: 4.9–9.8) and 170 events were documented. The Kaplan-Meier curves (figure 1) showed significant differences of MACCE in higher SSI, SSII and rSS (p=0.039, 0.033, <0.001 respectively). After multivariate adjustment, rSS, ejection fraction (EF) and age were found to be independent predictors of MACCE (p<0.001, 0.034 and 0.006, respectively).

Figure 1

Conclusion

In this sample SSI, II and residual were associated with the occurrence of events. However, just the rSS remained an independent predictor of MACCE together with age and EF.