Outcomes Following Coronary Artery Bypass Graft Surgery in Patients with Mild Preoperative Renal Insufficiency

Central Oxygen Venous Saturation and Mortality in Patients Undergoing Coronary Artery Bypass Grafting

Purpose

Central venous oxygen saturation (ScvO₂) has been reported as a prognostic marker of in-hospital mortality when it is below 60% in certain situations. Nevertheless, it has not been widely reported in patients undergoing coronary artery bypass graft (CABG). The study determined the association between ScvO₂ and in-hospital mortality in patients undergoing CABG in a high-complexity health institution in Santiago de Cali, Colombia.

Patients and Methods

A retrospective cohort study was conducted with patients undergoing isolated CABG. The subject sample included 515 subjects aged 18 years or older. Exposure was defined as ScvO₂ <60% upon admission to the intensive care unit (ICU) following surgery. The major outcome was mortality rates after 30 days. Furthermore, exposure variables were measured at preoperative, intra-operative, and postoperative time points.

Results

A total of 103 exposed and 412 unexposed subjects were included. The final model revealed a higher mortality risk in individuals with ScvO₂ <60% upon ICU admission compared with those with higher saturation levels (relative risk 4.2, 95% confidence interval: 2.4-7.2; p = 0.001). Values were adjusted using variables such as age (>75 years), low socioeconomic stratum, chronic kidney failure before surgery, unstable angina before surgery, ischemia time (>60 min), and intra-operative inotrope use. The primary cause of death was cardiogenic shock (54.7%), followed by sepsis (25.0%) and postoperative bleeding (17.2%).

Conclusion

The study identified an association between ScvO₂ <60% and in-hospital mortality in patients undergoing CABG.

Estimated glomerular filtration rate and postoperative mortality in patients undergoing non-cardiac and non-neuron surgery: a single-center retrospective study

Background

There is limited evidence to clarify the specific relationship between preoperative estimated glomerular filtration rate (preop-eGFR) and postoperative 30-day mortality in Asian patients undergoing non-cardiac and non-neuron surgery. We aimed to investigate details of this relationship.

Methods

We reanalyzed a retrospective analysis of the clinical records of 90,785 surgical patients at the Singapore General Hospital from January 1, 2012 to October 31, 2016. The main outcome was postoperative 30-day mortality.

Results

The average age of these recruited patients was 53.96 ± 16.88 years, of which approximately 51.64% were female. The mean of preop-eGFR distribution was 84.45 ± 38.56 mL/min/1.73 m². Multivariate logistic regression analysis indicated that preop-eGFR was independently associated with 30-day mortality (adjusted odds ratio: 0.992; 95% confidence interval [CI] 0.990–0.995; P < 0.001). A U-shaped relationship was detected between preop-eGFR and 30-day mortality with an inflection point of 98.688 (P for log likelihood ratio test < 0.001). The effect sizes and confidence intervals on the right and left sides of the inflection point were 1.013 (1.007 to 1.019) [P < 0.0001] and 0.984 (0.981 to 0.987) [P < 0.0001], respectively. Preoperative comorbidities such as congestive heart failure (CHF), type 1 diabetes, ischemic heart disease (IHD), and anemia were associated with the odds ratio of preop-eGFR to 30-day mortality (interaction P < 0.05).

Discussion

The relationship between preop-eGFR and 30-day mortality is U-shaped. The recommended preop-eGFR at which the rate of the 30-day mortality was lowest was 98.688 mL/min/1.73 m².

The impact of mild renal dysfunction on isolated cardiopulmonary coronary artery bypass grafting: a retrospective propensity score matching analysis

BACKGROUND

Mild preoperative renal dysfunction (RD) is not rare in patients receiving isolated cardiopulmonary coronary artery bypass grafting (CCABG). However, there are not too many studies about the impact of mild preoperative RD on in-hospital and follow-up outcomes after isolated CCABG. This single-centre, retrospective propensity score matching study designed to study the impact of mild preoperative RD on in-hospital and long-term outcomes after first isolated CCABG.

METHODS

After propensity score matching, 1144 patients with preoperative estimated glomerular filtration rate (eGFR) of more than 60 ml/min/1.73 m² receiving first isolated CCABG surgery from January 2012 to December 2015 entered the study, who were divided into 2 groups: A group (eGFR ≥90 ml/min/1.73 m2, n = 572) and B group (eGFR of 60-89 ml/min/1.73 m2, n = 572). The in-hospital and long-term outcomes were recorded and analyzed. The mean follow-up time was 54.4 ± 10.7 months. Acute kidney injury (AKI) was defined and classified according to the Acute Kidney Injury Network (AKIN) criteria.

RESULTS

The 2 propensity score-matched groups had similar baseline and procedure except the baseline eGFR. There were 8 patients died in A group (mortality is 1.4%) and 14 died in B group (mortality is 2.5%) during the in hospital and 30-day postoperatively(χ² = 1.159, p = 0.282). There were totally 38 patients lost to follow-up, 18 in group A and 20 in group B. 21 patients died in group A and 37 died in group B during the follow-up, and long-term survival in group A was higher than in group B (96.2% vs 93.1%, χ² = 4.336, p = 0.037). Comparing with group A, group B was associated with an increased rates and severity of AKI postoperatively (total AKI: 62 vs 144. AKIN stageI: 54 vs 113; AKIN stageII: 6 vs 22; AKIN stageIII: 2 vs 9, p<0.0001). During follow-up, group B also had a higher rate of new onset of dialysis (0 vs 6, χ² = 4.432, p = 0.039). Multivariable logistic regression showed that comparing with A group, the HR for long-term mortality and new onset of dialysis in B group was 1.67 and 1.52 respectively (95%CI 1.09-2.90, p = 0.035; 95%CI 1.14-2.49, p = 0.027).

CONCLUSIONS

Comparing with normal preoperative renal function, patients with mild preoperative RD had a similar in-hosptial mortality, but with an increased in-hosptial rates and severity of AKI, and with a decreased long-term survival and increased long-term new onset of dialysis.