Marco Ranucci

Risk of assessing mortality risk in elective cardiac operations: age, creatinine, ejection fraction, and the law of parsimony.

Background— Several mortality risk scores exist in cardiac surgery. All include a considerable number of independent risk factors. In elective cardiac surgery patients, the operative mortality is low, the number of events recorded per year is limited, and the risk model may be overfitted. The present study aims to develop and validate an operative mortality risk score for elective patients based on a limited number of factors. Methods and Results— The development series included 4557 adult patients who had undergone an elective cardiac operation at our institution from 2001 to 2003; the validation series includes the 4091 patients who subsequently underwent an operation. Three independent factors were included in the mortality risk model: age, creatinine, and left ventricular ejection fraction (ACEF). The ACEF score was computed as follows: age (years)/ejection fraction (%)+1 (if serum creatinine value was >2 mg/dL). The ACEF score was compared with 5 other risk scores in the validation series. Discriminatory power (accuracy) was defined with a receiver-operating characteristics analysis. The best accuracy was achieved by the Cleveland Clinic score (0.812), with ACEF score just below it (0.808). In coronary operations, the 2 scores performed equally well (0.815 versus 0.813), and in isolated coronary operations, the best accuracy was achieved by ACEF (0.826), with the Cleveland Clinic score at 0.806. Conclusion— A risk model limited to 3 independent predictors has similar or better accuracy and calibration compared with more complex risk scores if applied to elective cardiac operations.

Fenoldopam Reduces the Need for Renal Replacement Therapy and In-Hospital Death in Cardiovascular Surgery: A Meta-Analysis

OBJECTIVE Acute renal failure is a common and threatening complication in patients undergoing cardiovascular surgery. To determine the efficacy of fenoldopam in the prevention of acute renal failure, the authors performed a systematic review of randomized, controlled trials and propensity-matched studies in patients undergoing cardiovascular surgery. DESIGN Meta-analysis. SETTING Hospitals. PARTICIPANTS A total of 1,059 patients from 13 randomized and case-matched studies were included in the analysis. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Google Scholar, PubMed, and scientific sessions were searched (updated November 2006). Authors and external experts were contacted. Four unblinded reviewers selected controlled trials that used fenoldopam in the prevention or treatment of acute renal failure in cardiovascular surgery. Four reviewers independently abstracted patient data, treatment characteristics, and outcomes. Pooled estimates showed that fenoldopam consistently and significantly reduced the need for renal replacement therapy (odds ratio = 0.37 [0.23-0.59], p < 0.001) and in-hospital death (odds ratio = 0.46 [0.29-0.75], p = 0.01). These benefits were associated with shorter intensive care unit stay (weighted mean difference [WMD] = -0.93 days [-1.27; -0.58], p = 0.002). Sensitivity analyses, tests for small study bias, and heterogeneity assessment further confirmed the main analysis. CONCLUSIONS This meta-analysis provides evidence that fenoldopam may confer significant benefits in preventing renal replacement therapy and reducing mortality in patients undergoing cardiovascular surgery.

Multiple electrode whole-blood aggregometry and bleeding in cardiac surgery patients receiving thienopyridines

BACKGROUND Preoperative treatment with thienopyridines is associated with increased postoperative bleeding in cardiac surgery patients. Patients under treatment with thienopyridines have different levels of platelet dysfunction and the effects of discontinuation are not totally predictable. The present study aimed to determine if a preoperative assessment of platelet function in these patients could provide clinically relevant information regarding the risks of excessive postoperative bleeding and transfusion requirements. METHODS This is a retrospective analysis of prospectively collected data. Patients (n=87) under thienopyridine treatment until at least one week before cardiac surgery were enrolled in the study. Platelet function was assessed preoperatively with multiple electrode aggregometry: the adenosine diphosphate (ADP) test and TRAP (thrombin receptor-associated peptide) test were performed for all patients. RESULTS Univariate analysis revealed that postoperative bleeding was associated (p<0.1) with preoperative serum creatinine level, platelet count, CPB (cardiopulmonary bypass) duration, and results from the ADP test and the TRAP test. Multivariable linear regression analysis confirmed the CPB duration (p=0.049) and ADP test (p=0.007) as independently associated with postoperative bleeding. The relationship between the ADP test and postoperative bleeding was investigated with polynomial regression analysis, and a logarithmic equation provided the best fit. The accuracy of prediction was good (area under the curve 0.71, p=0.013), with a cutoff value for the ADP test at 31 U (sensitivity 72%, specificity 66%, negative predictive value 92%, and positive predictive value 29%). CONCLUSIONS The multiple electrode aggregometry ADP test in patients under thienopyridine treatment and undergoing cardiac surgery is associated with postoperative bleeding and platelet transfusion and provides an accurate preoperative prediction of postoperative bleeding risk.

Desmopressin reduces transfusion needs after surgery: a meta-analysis of randomized clinical trials.

Background:Perioperative pathologic microvascular bleeding is associated with increased morbidity and mortality and could be reduced by hemostatic drugs. At the same time, safety concerns regarding existing hemostatic agents include excess mortality. Numerous trials investigating desmopressin have lacked power to detect a beneficial effect on transfusion of blood products. The authors performed a meta-analysis of 38 randomized, placebo-controlled trials (2,488 patients) investigating desmopressin in surgery and indicating at least perioperative blood loss or transfusion of blood products. Methods:Pertinent studies were searched in BioMed Central, CENTRAL, and PubMed (updated May 1, 2008). Further hand or computerized searches involved recent (2003–2008) conference proceedings. Results:In most of the included studies, 0.3 &mgr;g/kg desmopressin was used prophylactically over a 15- to 30-min period. In comparison with placebo, desmopressin was associated with reduced requirements of blood product transfusion (standardized mean difference = −0.29 [−0.52 to −0.06] units per patient; P = 0.01), which were more pronounced in the subgroup of noncardiac surgery and were without a statistically significant increase in thromboembolic adverse events (57/1,002 = 5.7% in the desmopressin group vs. 45/979 = 4.6% in the placebo group; P = 0.3). Conclusions:Desmopressin slightly reduced blood loss (almost 80 ml per patient) and transfusion requirements (almost 0.3 units per patient) in surgical patients, without reduction in the proportion of patients who received transfusions. This meta-analysis suggests the importance of further large, randomized controlled studies using desmopressin in patients with or at risk of perioperative pathologic microvascular bleeding.

Hyperlactatemia during cardiopulmonary bypass: determinants and impact on postoperative outcome

IntroductionHyperlactatemia during cardiopulmonary bypass is relatively frequent and is associated with an increased postoperative morbidity. The aim of this study was to determine which perfusion-related factors may be responsible for hyperlactatemia, with specific respect to hemodilution and oxygen delivery, and to verify the clinical impact of hyperlactatemia during cardiopulmonary bypass in terms of postoperative morbidity and mortality rate.MethodsFive hundred consecutive patients undergoing cardiac surgery with cardiopulmonary bypass were admitted to this prospective observational study. During cardiopulmonary bypass, serial arterial blood gas analyses with blood lactate and glucose determinations were obtained. Hyperlactatemia was defined as a peak arterial blood lactate concentration exceeding 3 mmol/l. Pre- and intraoperative factors were tested for independent association with the peak arterial lactate concentration and hyperlactatemia. The postoperative outcome of patients with or without hyperlactatemia was compared.ResultsFactors independently associated with hyperlactatemia were the preoperative serum creatinine value, the presence of active endocarditis, the cardiopulmonary bypass duration, the lowest oxygen delivery during cardiopulmonary bypass, and the peak blood glucose level. Once corrected for other explanatory variables, hyperlactatemia during cardiopulmonary bypass remained significantly associated with an increased morbidity, related mainly to a postoperative low cardiac output syndrome, but not to mortality.ConclusionHyperlactatemia during cardiopulmonary bypass appears to be related mainly to a condition of insufficient oxygen delivery (type A hyperlactatemia). During cardiopulmonary bypass, a careful coupling of pump flow and arterial oxygen content therefore seems mandatory to guarantee a sufficient oxygen supply to the peripheral tissues.

Influence of the Timing of Cardiac Catheterization and the Amount of Contrast Media on Acute Renal Failure After Cardiac Surgery

Postoperative acute renal failure (ARF) is not uncommon after cardiac surgery and after angiography. However, limited information exists regarding the influence of the interval between cardiac catheterization and subsequent cardiac surgery and amount of contrast agent used during this procedure on the occurrence of postoperative ARF. Data for 423 consecutive adult patients who underwent elective cardiac surgery after cardiac catheterization were examined retrospectively. The influence of interval between cardiac catheterization and cardiac surgery on postoperative ARF (defined as postoperative serum creatinine > or =2 times baseline and >2 mg/dl and/or need for renal replacement therapy) was evaluated using multivariable logistic regression. ARF occurred in 24 patients (5.7%). Median time to angiography was 2 days (interquartile range 1 to 4.5), and median dose of contrast used was 1.36 ml/kg (interquartile range 1.12 to 1.69). Surgery on the day of cardiac catheterization was independently associated with increased risk of ARF (adjusted odds ratio 3.1, 95% confidence interval 1.1 to 8.8). This risk of ARF was highest in patients who underwent surgery on the same day as angiography and with a dose of contrast higher than median (14.6%) and lowest when surgery was delayed beyond 1 day of angiography and contrast dose was median or less (2.4%; adjusted odds ratio for same-day surgery and dose higher than median 4.2, 95% confidence interval 1.2 to 14.2). Cardiac surgery performed on the day of cardiac catheterization and higher dose of contrast agent used were both independently associated with increased risk of postoperative ARF. In conclusion, these findings suggest that delaying cardiac surgery beyond 24 hours of exposure to contrast agents (when feasible) and minimizing the use of these agents have significant potential to decrease the incidence of postoperative ARF in patients undergoing elective cardiac surgery.

Major bleeding, transfusions, and anemia: the deadly triad of cardiac surgery.

BACKGROUND Postoperative bleeding is common after cardiac surgery. Major bleeding (MB) is a determinant of red blood cell (RBC) transfusion, especially in patients with preoperative anemia. Preoperative anemia and RBC transfusions are recognized risk factors for operative mortality. The present study investigates the role of MB as an independent determinant of operative mortality in cardiac surgery. METHODS A single-center retrospective study based on the institutional database of cardiac surgery in the period 2000-2012 was conducted. Sixteen thousand one hundred fifty-four (16,154) consecutive adult patients undergoing cardiac surgery were analyzed. The impact of postoperative bleeding and MB on operative (30 days) mortality was analyzed univariately and after correction for preoperative anemia, RBC transfusions, and other confounders. RESULTS Postoperative bleeding was significantly (p < 0.001) associated with operative mortality, both in univariate and multivariable models. The main complications associated with MB were thromboembolic complications, infections, and surgical reexploration. In a multivariable model, MB remained an independent predictor of operative mortality (odds ratio, 3.45; 95% confidence interval, 2.78 to 4.28). Preoperative anemia and RBC transfusions coexist in the model, acting with a multiplying effect when associated with MB. CONCLUSIONS Major bleeding is per se a risk factor for operative mortality. However, its deleterious effects are strongly enhanced by RBC transfusions and, to a lesser extent, preoperative anemia. Major bleeding is a partially modifiable risk factor, and adequate preemptive and treatment strategies should be applied to limit this event.

Universal definition of perioperative bleeding in adult cardiac surgery

OBJECTIVES Perioperative bleeding is common among patients undergoing cardiac surgery; however, the definition of perioperative bleeding is variable and lacks standardization. We propose a universal definition for perioperative bleeding (UDPB) in adult cardiac surgery in an attempt to precisely describe and quantify bleeding and to facilitate future investigation into this difficult clinical problem. METHODS The multidisciplinary International Initiative on Haemostasis Management in Cardiac Surgery identified a common definition of perioperative bleeding as an unmet need. The functionality and usefulness of the UDPB for clinical research was then tested using a large single-center, nonselected, cardiac surgical database. RESULTS A multistaged definition for perioperative bleeding was created based on easily measured clinical end points, including total blood loss from chest tubes within 12 hours, allogeneic blood products transfused, surgical reexploration including cardiac tamponade, delayed sternal closure, and the need for salvage treatment. Depending on these components, bleeding is graded as insignificant, mild, moderate, severe, or massive. When applied to an established cardiac surgery dataset, the UDPB provided insight into the incidence and outcome of bleeding after cardiac surgery. CONCLUSIONS The proposed UDPB in adult cardiac surgery provides a precise classification of bleeding that is useful in everyday practice as well as in clinical research. Once fully validated, the UDPB may be useful as an institutional quality measure and serve as an important end point in future cardiac surgical research.

Transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis: Results from an intermediate risk propensity-matched population of the Italian OBSERVANT study

BACKGROUND Few studies have yielded information on comparative effectiveness of transcatheter aortic valve implantation (TAVI) versus surgical aortic valve replacement (SAVR) procedures in a real-world setting. The aim of this analysis is to describe procedural and post-procedural outcomes in a TAVI/SAVR intermediate risk propensity-matched population. METHODS OBSERVANT is an observational prospective multicenter cohort study, enrolling AS patients undergoing SAVR or TAVI. Propensity score method was applied to analyze procedural and post-procedural outcomes. Pairs of patients with the same probability score were matched (caliper matching). RESULTS The unadjusted enrolled population (N=2108) comprises 1383 SAVR patients, 602 transarterial-TAVI patients and 123 transapical-TAVI patients. Matched population comprised a total of 266 patients (133 patients for each group). A relatively low risk population was selected (mean logistic EuroSCORE 9.4 ± 10.4% vs 8.9 ± 9.5%, SAVR vs TAVI; p=0.650). Thirty-day mortality was 3.8% for both SAVR and TAVI (p=1.000). The incidence of stroke (1.5% SAVR and 0.0% TAVI; p=0.156) and myocardial infarction (0.8% SAVR and 0.8% TAVI; p=1.000) was not statistically different between groups, whereas a higher requirement for blood transfusion was reported across the surgical cohort (49.6% vs 36.1%; p=0.026). A higher incidence of major vascular damage (5.3% vs. 0.0%; p=0.007) and pacemaker implantation(0.8% vs 12.0%; p=0.001) were reported in the TAVI group. CONCLUSIONS Patients undergoing transcatheter and surgical treatment of severe aortic stenosis are still extremely distinct populations. In the relatively low-risk propensity-matched population analyzed, despite similar procedural and 30-day mortality, SAVR was associated with a higher risk for blood transfusion, whereas TAVI showed a significantly increased rate of vascular damage, permanent AV block and residual aortic valve regurgitation.

Impact of oligon central venous catheters on catheter colonization and catheter-related bloodstream infection

ObjectiveTo evaluate a new antimicrobial treatment for central venous catheters in comparison with a traditional treatment, by assessing the catheter colonization and catheter-related bloodstream infection rates in two groups of patients. DesignMultiple-center, prospective randomized study. SettingThe medical and surgical departments of ten institutions. PatientsPatients requiring a central venous catheter for medical or surgical pathologies between June 2000 and November 2001. InterventionsPatients in the control group received a conventional benzalkonium-treated double-lumen central venous catheter, while patients in the oligon group received an oligon-treated (polyurethane combined with silver, carbon, and platinum) catheter with the same characteristics. Data collection included demographics, preexisting clinical conditions, main pathology, catheter insertion, and management data. Catheter colonization was defined as the growth of ≥15 colony-forming units in culture of catheter segments by the roll-plate method, or ≥1000 colony-forming units for the sonication method, and catheter-related bloodstream infection was defined as isolation of the same organism from the colonized catheter and from the peripheral blood of a patient with clinical signs of bloodstream infection. Measurements and Main ResultsData were obtained from 545 catheters. Of these, 132 catheters (24.2%) were positive for colonization. Patients in the oligon group demonstrated a lower risk for catheter colonization in the overall population (relative risk, 0.63; 95% confidence interval, 0.46–0.86;p = .003) and in the surgical subgroup (relative risk, 0.5; 95% confidence interval, 0.33–0.76;p = .001). Significant differences between groups were detected for coagulase-negative staphylococci and Gram-negative bacilli colonization rates. Twenty-one patients (3.8%) were positive for catheter-related bloodstream infection, without significant differences between control and oligon groups. ConclusionsOligon treatment is effective in limiting the catheter colonization rate. Due to the limited amount of events, this study lacked the power to detect significant differences in terms of catheter-related bloodstream infection rate.