Krzysztof Nycz

Bedside Ultrasonographic Measurement of the Inferior Vena Cava Fails to Predict Fluid Responsiveness in the First 6 Hours After Cardiac Surgery: A Prospective Case Series Observational Study

OBJECTIVE To assess validity of respiratory variation of inferior vena cava (IVC) diameter to predict fluid responsiveness and guide fluid therapy in mechanically ventilated patients during the first 6 hours after elective cardiac surgery. DESIGN Prospective observational case series study. SETTING Single-center hospital. PATIENTS 50 consecutive patients undergoing elective cardiac surgery. INTERVENTIONS Transthoracic bedside echocardiography. MEASUREMENTS AND MAIN RESULTS Parameters derived from ultrasonographic assessment of the IVC diameter (collapsibility index [CI], distensibility index [DI], and IVC/aorta index). In the whole study group, change in fluid balance correlated with change in IVC maximum diameter (p = 0.034, r = 0.176). IVC-CI and IVC-DI correlated with IVC/aorta index. A weak correlation between central venous pressure (CVP) and IVC-derived parameters (IVC-CI and IVC-DI) was noticed. Despite statistical significance (p<0.05), all observed correlations expressed low statistical power (r<0.21). There were no statistically significant differences between fluid responders and nonresponders in relation to clinical parameters, CVP, ultrasound IVC measurement, and IVC-derived indices. CONCLUSION Dynamic IVC-derived parameters (IVC-CI, IVC-DI, and IVC/aorta index) and CVP are not reliable predictors of fluid responsiveness in the first 6 hours after cardiac surgery. Complexity of physiologic factors modulating cardiac performance in this group may be responsible for the difficulty in finding a plausible monitoring tool for fluid guidance. Bedside ultrasonographic measurement of IVC is unable to predict fluid responsiveness in the first 6 hours after cardiac surgery.

The effect of chronic kidney disease on fibrin clot properties in patients with acute coronary syndrome.

Chronic kidney disease (CKD), defined as a decreased estimated glomerular filtration rate (eGFR < 60 ml/min), is an independent risk factor for cardiovascular events. Both acute coronary syndrome (ACS) and end-stage renal disease have been shown to be associated with formation of compact fibrin clots relatively resistant to lysis. The aim of the current study was to evaluate the effect of CKD on fibrin clot properties in patients with ACS. In 30 ACS patients, aged 48–72 years, with CKD and 30 ACS patients with eGFR more than 60 ml/min, we investigated plasma fibrin clot properties using permeation and turbidity assays, including three different clot lysis assays. The ACS patients with eGFR less than 60 ml/min and those with normal filtration rate did not differ with regard to demographics, risk factors, medications and routine laboratory tests, including fibrinogen. The former group had higher plasminogen activator inhibitor-1 (P = 0.002) and tissue-type plasminogen activator (tPA) (P = 0.008). Compared with ACS patients with eGFR more than 60 ml/min, the ACS patients with CKD formed less porous fibrin clots (P = 0.004) and susceptible to fibrinolysis (P < 0.001), had thicker overall fibrin fibers (P = 0.007), earlier onset of fibrin clot formation (P = 0.004) and increased clot mass (P < 0.001). By multiple regression analysis, clot permeability was independently predicted by eGFR (P = 0.0005) and fibrinogen (P = 0.001), whereas the only predictors of lysis time were eGFR (P = 0.006) and tPA (P = 0.002). This study indicates that ACS patients with CKD display unfavorable fibrin clot properties including impaired fibrinolysis, which might contribute to worse outcome in this population.

Feasibility and accuracy of bedside transthoracic echocardiography in diagnosis of acute proximal aortic dissection

Study objectiveThe purpose of the present study was to establish the accuracy of transthoracic echocardiography (TTE) in diagnosis of acute type A aortic dissection in comparison to computed tomography (CT), with reference to the intraoperative image.MethodsThe retrospective analysis included 178 patients referred to the cardiac surgery unit in our center due to acute type A dissection between 01-01-2008 and 31-12-2013, who underwent both TTE and CT. Intraoperative image was considered as a reference.ResultsStatistical analysis did not show any significant differences between computed tomography and echocardiography in the detection of the proximal aortic dissection. In patients with aortic valve abnormalities, procedure of choice was replacement by a composite graft (77,59%), whereas patients with a normal image of aortic valve were more likely to have the valve sparing procedure (50,88%). The R-Spearman statistics shows a strong positive correlation between maximum diameter of ascending aorta measured by TTE and CT (cc 0.869) and TTE and intraoperative measurement (cc 0.844).ConclusionOur data confirm that transthoracic echocardiography is a reliable method for diagnosis of proximal aortic dissection. TTE provides a reliable value of maximum diameter of the ascending aorta in comparison to both CT and direct intraoperative measurement. Moreover, transthoracic echocardiography gives the additional information that influences the operative technique of choice and identifies the high-risk patients (cardiac tamponade, severe aortic dilatation, severe aortic regurgitation). Our retrospective analysis confirms the pivotal role of TTE in the evaluation of the patients with suspected proximal aortic dissection in emergency room setting.

Evolution of myocardial perfusion during primary angioplasty in spontaneously reperfused infarct-related artery: impact on long-term clinical outcomes and left ventricular function recovery.

BACKGROUND TIMI myocardial perfusion grade (TMPG) reflects the integrity of microvasculature in ST-elevation myocardial infarction (STEMI). We sought to investigate whether TMPG evolution during primary angioplasty (pPCI) in spontaneously reperfused STEMI patients might predict long-term outcomes. METHODS 392 patients with TIMI-3 flow before pPCI were analyzed. According to pre- and post-pPCI TMPG four reperfusion patterns were created: A. TMPG deterioration from grade 2/3 to 0/1 after pPCI (n = 55, 14.0%), B. TMPG-0/1 before and after pPCI (n = 111, 28.3%), C. TMPG improvement from grade 0/1 to 2/3 (n = 52, 13.3%), D. TMPG-2/3 before and after pPCI (n = 174, 44.4%). 30-day and 1-year mortality and heart failure requiring hospitalization (HF-hosp) were recorded. Left ventricular ejection fraction (LVEF) was measured at first day (1D) and after 6 months (6M). RESULTS 1D-LVEF was similar in A-D groups. After 6M, LVEF improved in pattern D (7.5 ± 5.4%, p<0.01) and C (3.7 ± 3.4%, p < 0.05), deteriorated in pattern A (5.2 ± 3.9%, p<0.01) and did not change in pattern B. 6M-LVEF increased (p < 0.001) and frequency of 1-year HF-hosp decreased (p < 0.001) in stepwise fashion among A-D patterns. A 30-day mortality rate for A-D patterns was 9.1%, 2.7%, 1.9% and 0%, respectively (p < 0.001). 1-year mortality was 16.3%, 7.2%, 5.8% and 0.6%, respectively (p < 0.001). By multivariate analysis (c-index = 0.79), TMPG evolution was independent predictor of 1-year mortality (HR = 2.5, 95%CI 1.3-4.0, p = 0.006). CONCLUSIONS Maintaining TMPG-2/3 or improving TMPG-0/1 through pPCI in STEMI implies LV function recovery and good long-term survival. In contrast, substantial deterioration of TMPG is associated with lack of LV function recovery, and the highest mortality rate.

New diastolic cardiomyopathy in patients with severe accidental hypothermia after ECMO rewarming: a case-series observational study

IntroductionAccidental hypothermia is a condition associated with significant morbidity and mortality. Hypothermia has been reported to affect left ventricular systolic and diastolic function. However, most of the data come from animal experimental studies.Aim of the studyThe purpose of the present study was to assess the impact of severe accidental hypothermia on systolic and diastolic ventricular function in patients treated using veno-arterial extracorporeal membrane oxygenation (ECMO).MethodsWe prospectively assessed nine hypothermic patients (8 male, age 25–78 years) who were transferred to the Severe Accidental Hypothermia Center and treated with ECMO. Transthoracic echocardiography was performed on admission (in patients without cardiac arrest) and on discharge from ICU after achieving cardiovascular stability. Cardiorespiratory stability and full neurologic recovery was achieved in all patients.ResultsBiomarkers of myocardial damage (CK, CKMB, hsTnT) were significantly elevated in all study patients. Admission echocardiography performed in patients in sinus rhythm, revealed moderate-severe bi-ventricular systolic dysfunction and moderate bi-ventricular diastolic dysfunction. Discharge echocardiography showed persistent mild bi-ventricular diastolic dysfunction, although systolic function of both ventricles returned to normal. Discharge echocardiography in patients admitted with cardiac arrest showed normal (5 patients) or moderately impaired (1 patient) global LV systolic function on discharge. However, mild or moderate LV diastolic dysfunction was observed in all 6 patients. Discharge RV systolic function was normal, whereas mild RV diastolic dysfunction was present in these patients.ConclusionAfter severe accidental hypothermia bi-ventricular diastolic dysfunction persists despite systolic function recovery in survivors treated with ECMO.

Ultrasonographic caval indices do not significantly contribute to predicting fluid responsiveness immediately after coronary artery bypass grafting when compared to passive leg raising

BackgroundAppropriate fluid management is one of the most important elements of early goal-directed therapy after cardiothoracic surgery. Reliable determination of fluid responsivenss remains the fundamental issue in volume therapy.The purpose of the study was to assess the usefulness of dynamic IVC-derived parameters (collapsibility index, distensibility index) in comparison to passive leg raising, in postoperative fluid management in mechanically ventilated patients with left ventricular ejection fraction ≥ 30 %, immediately after elective coronary artery bypass grafting.MethodsProspective observational case series study including 35 patients with LVEF ≥ 30 %, undergoingelective coronary artery bypass grafting was conducted. Transthoracic echocardiography, passive leg raising and intravenous administration of saline were performed in all study subjects. Dynamic parameters derived from ultrasonographic assessment of the IVC diameter (collapsibility index–CI and distensibility index–DI), cardiac outputResultsThere were 24 (68.57 %) responders in the study population. There were no statistical differences between the groups in relation to: clinical parameters, pre- and postoperative LVEF, fluid balance and CVP. Change in cardiac output after passive leg raising correlated significantly with that after the volume expansion (p=0.000, r=0.822). Dynamic IVC derivatives were slightly higher in fluid responders, however this trend did not reach statistical significance. None of the caval indices correlated with fluid responsiveness.ConclusionDynamic IVC-derived parameters do not predict fluid responsiveness in mechanically ventilated patients with preserved ejection fraction immediately after elective coronary artery bypass grafting. Passive leg raising is not inferior to volume expansion in differentiating between fluid responders and nonresponders. Immediate fluid challenge after CABG is safe and well tolerated.

A comparison of the ultrasound measurement of the inferior vena cava obtained with cardiac and convex transducers

Background Ultrasound measurement of the inferior vena cava diameter and its respiratory variability are amongst the predictors of fluid volume status. The primary purpose of the present study was to compare the consistency of inferior vena cava diameter measurements and the collapsibility index, obtained with convex and cardiac transducers. A secondary aim was to assess the agreement of the patient’s allocation to one of the two groups: “fluid responder” or “fluid non-responder”, based on inferior vena cava collapsibility index calculation made with two different probes. Methods 20 experienced clinicians blinded to the purpose of the study analysed forty anonymized digital clips of images obtained during ultrasound examination of 20 patients. For each patient, one digital loop was recorded with a cardiac and the second with a convex probe. The participants were asked to determine the maximal and minimal diameters of the inferior vena cava in all presented films. An independent researcher performed a comparative analysis of the measurements conducted with both probes by all participants. The calculation of the collapsibility index and allocation to “fluid responder” or “fluid non-responder” group was performed at this stage of the study. Results The comparison of measurements obtained with cardiac and convex probes showed no statistically significant differences in the measurements of the maximal and minimal dimensions and in the collapsibility index. We also noticed that the decision of allocation to the “fluid responder” or “non-responder” group was not probe-dependent. Conclusion Both transducers can be used interchangeably for the estimation of the studied dimensions.