Diagnostic Value of Procalcitonin and Interleukin-6 on Early Postoperative Pneumonia after Adult Cardiac Surgery: A Prospective Observational Study

Background: Postoperative pneumonia (PP) is the most common primary infection after cardiac surgery, increasing the hospitalization expense and causing the consumption of healthcare resources. This study aimed to investigate the diagnostic value of procalcitonin (PCT) and interleukin-6 (IL-6) on early postoperative pneumonia after adult cardiac surgery. Methods: In this prospective observational study, patients with pneumonia and age- and sex-matched cases in our center from October 10, 2020 to January 31, 2021 were included. Patients diagnosed with pneumonia in this study needed meet both clinical and microbiological diagnostic criteria. Blood samples were collected in all patients from postoperative day (POD) 1 to postoperative day 5 to detect PCT, IL-6, white blood cell count, and C-reactive protein. The diagnostic performance of different biomarkers was evaluated by the receiver operating characteristic curves and the area under the curves. Results: Our study enrolled 272 patients, including 24 patients with postoperative pneumonia and 248 age- and sex-matched cases. From POD1 to POD5, the absolute value of PCT and PCT variations showed diagnostic significance for pneumonia (P < .05); the diagnostic value of the absolute value of IL-6 and IL-6 variations was not satisfying. White blood cell count showed no differences; C-reactive protein had no diagnostic value before POD4. Multivariable logistic regression showed that PCT variation and IL-6 variation from POD3 to POD1 were the strongest risk factors for postoperative pneumonia [OR:12.50, 95% CI: (3.40-45.5); OR:13.71, 95% CI: (1.11-168.47)]. According to the above results, we defined the PL Index. PL Index showed the best diagnostic value among those biomarkers in POD3 [AUC: 0.90, 95% CI: (0.79-0.95)]. Multivariable logistic regression showed PL Index POD3 has significant correlation with postoperative pneumonia [OR:1.23, 95% CI: (1.11-1.37), P = .041]. Conclusions: PCT variation and IL-6 were more accurate than C-reactive protein and white blood cell count to predict early postoperative pneumonia, but the diagnostic properties of PCT could not be observed during the first three postoperative days due to the inflammatory process. By combining the variations of PCT and IL-6, we defined the PL Index, which shows the best diagnostic ability on early postoperative pneumonia after adult cardiac surgery.

Efficacy of Pulsatile Flow Perfusion in Adult Cardiac Surgery: Hemodynamic Energy and Vascular Reactivity

Background: The role of pulsatile (PP) versus non-pulsatile (NP) flow during a cardiopulmonary bypass (CPB) is still debated. This study’s aim was to analyze hemodynamic effects, endothelial reactivity and erythrocytes response during a CPB with PP or NP. Methods: Fifty-two patients undergoing an aortic valve replacement were prospectively randomized for surgery with either PP or NP flow. Pulsatility was evaluated in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE). Systemic (SVRi) and pulmonary (PVRi) vascular resistances, endothelial markers levels and erythrocyte nitric-oxide synthase (eNOS) activity were collected at different perioperative time-points. Results: In the PP group, the resultant EEP was 7.3% higher than the mean arterial pressure (MAP), which corresponded to 5150 ± 2291 ergs/cm3 of SHE. In the NP group, the EEP and MAP were equal; no SHE was produced. The PP group showed lower SVRi during clamp-time (p = 0.06) and lower PVRi after protamine administration and during first postoperative hours (p = 0.02). Lower SVRi required a higher dosage of norepinephrine in the PP group (p = 0.02). Erythrocyte eNOS activity results were higher in the PP patients (p = 0.04). Renal function was better preserved in the PP group (p = 0.001), whereas other perioperative variables were comparable between the groups. Conclusions: A PP flow during a CPB results in significantly lower SVRi, PVRi and increased eNOS production. The clinical impact of increased perioperative vasopressor requirements in the PP group deserves further evaluation.

Del Nido versus HTK cardioplegia for myocardial protection during adult complex valve surgery: a retrospective study

Background Histidine-tryptophan-ketoglutarate (HTK) and del Nido (DN) cardioplegia are intracellular-type and extracellular-type solution respectively, both can provide a long period of myocardial protection with single-dose infusion, but studies comparing the two are rare for adult cardiac surgery. This study aims to evaluate whether DN is suitable for cardioplegia in complex and high-risk valve surgery with long-term cardiac ischemia when compared with HTK. Methods The perioperative records of adult patients infused with DN/HTK as a cardioplegic solution who underwent complex valve surgery with an expected myocardial ischaemic duration longer than 90 min between Oct 2018 and Oct 2019 were analysed retrospectively. Results Of the 160 patients who received DN/HTK and underwent complex valve surgery, we propensity matched 73 pairs. Both groups achieved satisfactory cardiac arrest effects, and no significant difference was found in their cTnI and CK-MB levels within 12 to 72 h postoperatively. The DN group had a higher rate of return to spontaneous rhythm (0.88 v 0.52, P < 0.001), a lower frequency of postoperative severe arrythmias (12% v 26%, P = 0.036), a higher postoperative stroke volume (65 v 59 ml, P = 0.011) and a higher cardiac output (6.0 v 4.9 L/min, P = 0.007) as evaluated by echocardiography, fewer transfusions and shorter ICU stays (both P < 0.05). The two groups had similar inotrope usage and similar incidences of low cardiac output, morbidities and mortality. Subgroup analysis showed that when the aortic clamping time was greater than 120 min, the advantages of DN were weakened. Conclusions DN can be safely applied to complex valve surgery, and it has a similar myocardial protection effect as HTK. Further prospective studies are required to verify these retrospective findings. Trial registration retrospectively registered.

Fibrinogen and Bleeding in Adult Cardiac Surgery: A Review of the Literature

Background: Fibrinogen is a substrate for blood clots formation. In cardiac surgery, a number of different mechanisms lead to a decrease in fibrinogen levels and consequent impaired haemostasis. Patients undergoing cardiac surgery are therefore frequently exposed to blood loss and allogeneic blood transfusion, which are risk factors associated with morbidity and mortality. Thus, particular efforts in fibrinogen management should be made to decrease bleeding and the need for blood transfusion. Therefore, fibrinogen remains an active focus of investigations from basic science to clinical practice. This review aims to summarise the latest evidence regarding the role of fibrinogen and current practices in fibrinogen management in adult cardiac surgery. Methods: The PubMed database was systematically searched for literature investigating the role and disorders of fibrinogen in cardiac surgery and diagnostic and therapeutic procedures related to fibrinogen deficiency aimed at reducing blood loss and transfusion requirements. Clinical trials and reviews from the last 10 years were included. Results: In total, 146 articles were analysed. Conclusion: The early diagnosis and treatment of fibrinogen deficiency is crucial in maintaining haemostasis in bleeding patients. Further studies are needed to better understand the association between fibrinogen levels, bleeding, and fibrinogen supplementation and their impacts on patient outcomes in different clinical settings.

Red blood cell transfusion induces abnormal HIF-1α response to cytokine storm after adult cardiac surgery

Patients undergoing cardiac surgery develop a marked postoperative systemic inflammatory response. Blood transfusion may contribute to disruption of homeostasis in these patients. We sought to evaluate the impact of blood transfusion on serum interleukin-6 (IL-6), hypoxia induced factor-1 alpha (HIF-1α) levels as well as adverse outcomes in patients undergoing adult cardiac surgery. We prospectively enrolled 282 patients undergoing adult cardiac surgery. Serum IL-6 and HIF-1α levels were measured preoperatively and on the first postoperative day. Packed red blood cells were transfused in 26.3% of patients (mean 2.93 ± 3.05 units) by the time of postoperative sampling. Postoperative IL-6 levels increased over 30-fold and were similar in both groups (p = 0.115), whilst HIF-1α levels (0.377 pg/mL vs. 0.784 pg/mL, p = 0.002) decreased significantly in patients who received red blood cell transfusion. Moreover, greater decrease in HIF-1α levels predicted worse in-hospital and 3mo adverse outcome. Red blood cell transfusion was associated with higher risk of major adverse outcomes (stroke, pneumonia, all-cause mortality) during the index hospitalization. Red blood cell transfusion induces blunting of postoperative HIF-1 α response and is associated with higher risk of adverse thrombotic and pulmonary adverse events after cardiac surgery. Clinical Trial Registration ClinicalTrials.gov Identifier: NCT03444259.