| JOURNAL HOME | CME HOME | THIS MONTH | PAST ISSUES | ETOC | COLLECTIONS |
| AUTHORS | REVIEWERS | EDITORIAL BOARD | FEEDBACK | RSS | HELP |
 
|
|
|
||
|
|
Anesth Analg 2003;97:950-957 © 2003 International Anesthesia Research Society
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Interpretation of perioperative measurements of cardiac function during cardiac surgery is complicated by changes in loading conditions induced by anesthesia, cardiopulmonary bypass (CPB), and the surgical procedure itself. Quantification of left ventricular (LV) function by pressure-volume relations as obtained by the conductance catheter would be advantageous because load-independent indices can be determined. Accordingly, we evaluated methodological aspects of the conductance-catheter technique and documented LV function before and after CPB in eight patients undergoing coronary artery bypass grafting. LV pressure-volume loops by transesophageal echocardiography-guided transaortic application of the conductance catheter were obtained at steady-state and during preload reduction by temporary occlusion of the inferior cava. All patients remained hemodynamically stable, and no complications occurred. Complete data were acquired within 15 min before and after CPB. Cardiac output (5.2 ± 1.3 L/min to 6.0 ± 1.4 L/min) and LV ejection fraction (46% ± 17% to 48% ± 19%) did not change, but end-diastolic pressure increased significantly after CPB (8 ± 2 mm Hg to 16 ± 7 mm Hg; P < 0.05). Load-independent systolic indices remained constant (end-systolic elastance: 1.31 ± 1.20 mm Hg/mL to 1.13 ± 0.59 mm Hg/mL). Diastolic function changed significantly after CPB, as the relaxation time constant decreased from 64 ± 6 ms to 52 ± 5 ms (P < 0.05) and the chamber stiffness constant increased from 0.016 ± 0.014/mL to 0.038 ± 0.016/mL (P < 0.05). We conclude that the conductance catheter method provides detailed data on perioperative myocardial function and may be useful for evaluating the effects of new surgical and anesthetic procedures.
IMPLICATIONS: Pressure-volume loops provide on-line quantification of intrinsic systolic and diastolic myocardial function in a load-independent fashion. This study shows the feasibility of perioperative pressure-volume analysis by use of the conductance-catheter method. This method provides detailed data about the immediate effects of surgery and may be used to evaluate complex cardiac procedures.
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Recently, several new approaches were introduced in cardiac surgery, such as undersized mitral annuloplasty, endoventricular circular patch-plasty, and off-pump coronary artery bypass grafting (CABG). Generally, the efficacy of new techniques is assessed by long-term follow-up of patients. However, the acute effects on left ventricular (LV) function of these procedures are not well documented and may be predictive of long-term outcome. Perioperative assessment of LV function may allow better evaluation of new surgical procedures and may help postoperative management by providing insight into cardiac pathophysiology. During cardiac surgery, cardiac output (CO), aortic pressure, central venous pressure, and pulmonary arterial wedge pressure are commonly used to assess hemodynamic status. In addition, transesophageal echocardiography (TEE) is used to assess regional contractile function. However, interpretation of all these variables is complicated by their load dependency. Therefore, given the substantial changes in loading conditions that may occur during cardiac surgery, these variables may not reflect intrinsic myocardial function. Pressure-volume relations, as obtained by the conductance catheter (1), have been shown to provide load-independent indices of systolic and diastolic function (2). Accordingly, the aim of this study was twofold: First, we described and evaluated the application of the conductance technique in the operating room, including catheter placement, calibration procedures, and heart rate (HR)-controlled measurement of systolic and diastolic pressure-volume relations. Second, we compared various indices of LV function before and after cardiopulmonary bypass (CPB) in patients undergoing CABG. These data obtained in patients with relatively normal LV function may provide reference data for future studies evaluating more complex cardiac surgical procedures.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The study protocol was approved by our local Ethics Committee, and all patients gave informed consent. Eight patients with multivessel coronary artery disease elected for CABG were included. Patients with severely depressed LV function (LV ejection fraction [EF] <35%), unstable angina, or atrial fibrillation were excluded.
After 2 mg of lorazepam as sublingual premedication 2 h before surgery, all patients received total IV anesthesia with target-controlled infusion of propofol, remifentanil, and sufentanil (3–5). The hypnotic state was monitored with a bispectral index monitor (Aspect Medical Systems, Newton, MA). The induction of anesthesia was started with a targeted concentration of propofol 1.5 µg/mL and remifentanil 3 ng/mL. Before intubation, the remifentanil-targeted concentration was increased to 9 ng/mL and the targeted propofol concentration to 2 µg/mL. A single dose of pancuronium bromide (0.1 mg/kg) was given to facilitate intubation. During surgery, the propofol concentration was adjusted between 1.5 and 2.0 µg/mL to maintain a bispectral index value less than 60. Remifentanil was titrated between 5 and 10 ng/mL in response to the patient’s hemodynamic reaction on surgical stimuli. Sufentanil was started at a targeted concentration of 0.1 ng/mL after the start of surgery to allow smooth transition of the patient’s analgesic state from the operating room to the intensive care unit (ICU). The patients were ventilated with an oxygen/air mixture (fraction of inspired oxygen, 40%) at a ventilatory rate of 12–15 breaths/min, and ventilatory volume was adjusted to maintain PaCO2 between 4.5 and 5.5 kPa (34–41 mm Hg). A thermal filament catheter was placed with its tip in the pulmonary artery via the right internal jugular vein for semicontinuous CO measurements (Edwards Lifesciences, Uden, The Netherlands). A multiplane TEE probe was inserted to monitor cardiac function and facilitate positioning of the conductance catheter perioperatively.
We used a 7F integrated pressure-conductance catheter (CD-Leycom, Zoetermeer, The Netherlands) incorporating a solid-state pressure sensor and 12 electrodes with an interelectrode spacing of 10 mm. A pigtail facilitates placement through the aortic valve and positioning within the LV apex (Fig. 1). The catheter is connected to a Leycom Cardiac Function Lab signal processor. Between the two most proximal and two most distal electrodes, a dual electric field (20 kHz; 30 µA) is generated (6). The remaining eight electrodes are used to measure five segmental volume signals. The user may select from three settings the best match with the LV long axis: by skipping electrodes 1 or 2, 1-cm segments may be converted to 2-cm segments, thereby extending the effective length of the catheter. The optimal setting is selected on the basis of inspection of the segmental volume signals. An aortic volume signal is easily distinguished from a ventricular signal because it resembles an aortic pressure signal and is out of phase with the ventricular volume signals. The segmental conductance values are summed to yield total conductance [G(t)] and, taking into account the specific resistivity of blood and the electrode spacing, converted to a time-varying volume signal, V(t), which follows through the equation:
|
|
|
where
is a slope factor, L is the interelectrode spacing, rho is the specific resistivity of blood measured from a 5-mL blood sample by using a special four-electrode cuvette connected to the Cardiac Function Lab, and GP is the parallel conductance. G(t) is the sum of the conductance of the blood in the LV and GP. The latter results from the conductance of the ventricular wall, other cardiac chambers, and, to some extent, all electrically conductive structures outside the LV cavity. Baan et al. (1) devised a method to determine GP by injecting a small bolus (7 mL) of hypertonic saline solution (10%) in the distal port of the pulmonary artery catheter. The highly conductive saline transiently changes blood conductivity, which is measured only in the LV. By analyzing the conductance signal registered during passage of the bolus through the LV, GP can be determined (1). The correction volume (Vc) corresponding to GP can be determined as follows: equation
|
|
After correction for GP, the volume signal is directly proportional to actual ventricular volume but generally underestimates true volume by a fixed factor. There are two main causes for this underestimation. First, there may be a mismatch between the measured segments and the LV long axis. Second, the conversion of conductance to volume assumes that the electric field is homogeneous within the cavity. In reality, this is not entirely the case, and the result is underestimation. The development of dual-field excitation (6) has substantially improved electric field homogeneity, but some underestimation remains, especially in large hearts. To correct for this underestimation, the factor was introduced, which is obtained by comparing conductance-derived stroke volume (SV) with an independent measure of SV. In most studies, is calculated by dividing SV of the conductance catheter by SV obtained by thermodilution: = SVconductance/SVthermodilution. In this study, we compare conductance values with the "stat" CO measurements recorded from a Vigilance® Continuous Cardiac Output Monitoring System (Edwards Lifesciences).
After bypass material was harvested, the pericardium was opened, and epicardial pacemaker leads were placed on the right atrium. A caval tourniquet was applied around the inferior cava to perform temporary preload reductions by caval vein occlusion. After systemic heparinization, a sheath (F8; Cordis, Roden, The Netherlands) was introduced into the ascending aorta for placement of the conductance catheter. Subsequently the conductance catheter was inserted into the LV and positioned along the long axis toward the LV apex. Catheter introduction and positioning were guided and verified by TEE and inspection of the segmental conductance signals. Positioning was aimed at locating the pigtail in the apex and locating the most proximal electrodes just above the aortic valve. Measurements were obtained if five segmental LV volume signals were obtained.
The protocol included measurements at a paced HR of 80 bpm before and after CPB. If the intrinsic rate was more than 80 bpm, the pacemaker was set slightly above the intrinsic rate. Pressure-volume loops were measured at steady-state and during transient vena caval occlusion (typical pressure decrease of 20 mm Hg within 5–10 s) to obtain systolic and diastolic pressure-volume relationships. Mechanical ventilation was interrupted to exclude the effects of respiration. Rho was measured just before data acquisition, both before and after CPB. Additional acquisitions (before and after CPB) were performed for determination of GP after the injection of 7 mL of 10% hypertonic saline solution through the distal port of the pulmonary artery catheter. Independent CO measurements by thermodilution were obtained during steady-state. The thermodilution catheter provides update measurements approximately every minute that indicate average CO over the preceding period. An analog signal reflecting the "stat" signal was recorded simultaneously with the pressure-volume signals for off-line calculation of .
Baseline hemodynamic data were calculated from steady-state pressure-volume loops: HR, end-systolic volume, end-diastolic volume (EDV), end-systolic pressure (ESP), end-diastolic pressure (EDP), CO, SV, stroke work (SW), maximal and minimal rate of LV pressure change (dP/dtMAX and dP/dtMIN), EF, and the relaxation time constant (Tau). Tau, reflecting the early active relaxation process, was calculated as the time constant of monoexponential pressure decay during isovolumic relaxation. The isovolumic period was defined as the period between the time point of dP/dtMIN and the time point at which dP/dt reached 10% of the dP/dtMIN value. Indices of systolic and diastolic function were derived from pressure-volume loops during caval vein occlusion. For systolic function, the ESP-volume relation (ESPVR), the dP/dtMAX-EDV relation, and the preload recruitable stroke work relation (PRSW; SW versus EDV) were determined, and for diastolic function, the chamber stiffness constant (CS) was determined. The systolic relationships were characterized by their slope and volume intercept. The slope of the ESPVR (Ees) and its volume intercept at a fixed systolic pressure of 75 mm Hg are indices of contractility that are largely independent of loading conditions (7,8). The ESPVR was determined by linear regression of ESP-volume points obtained during caval vein occlusion. Similarly, the PRSW slope was determined by plotting SW against EDV, and the same was done for the slope of the dP/dtMAX-EDV relation. The slopes of these two relationships also reflect contractility (9,10). CS was determined by exponential regression of the EDPVR by means of the following equation: equation
|
|
where yo is the pressure asymptote and A is a constant.
Pre- and post-CPB data were compared by using paired Student’s t-tests. Statistical significance was assumed at P < 0.05. All data are presented as mean ± SD.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Patient characteristics are shown in Table 1. All patients underwent normothermic CPB and intermittently received antegrade warm oxygenated blood cardioplegia. The surgical procedure and postoperative ICU stay were uncomplicated. Perioperative and postoperative electrocardiograms did not show signs of ischemia. Furthermore, troponin T levels were measured at least up to 12 hours after surgery and did not exceed 0.6 µg/L at any time point, indicating that perioperative myocardial infarction occurred in none of the patients (11).
|
In all patients, complete pressure-volume data were acquired before and after CPB. Preparation of the pacemaker wires, application of the caval tourniquet, and introduction of the sheath were uncomplicated. The introduction of the conductance catheter through the aortic valve and catheter placement required careful monitoring by use of TEE (Fig. 1) to reduce the risks of perforation and to obtain an optimal catheter position. The optimal transesophageal long-axis view was obtained with the multiplane TEE probe from the midesophageal transducer position with the array at 135° of rotation. Occasionally, placement of the catheter within the apex caused ventricular extrasystolic beats, but a stable catheter position without arrhythmias could always be obtained. After the pre-CPB measurements, the conductance catheter was withdrawn, rinsed with normal saline, and placed on a sterile table to be reused after CPB. During CPB, the introducer sheath on the ascending aorta was used to infuse cardioplegia. Catheter placement and measurements before and after CPB were completed within approximately 15 minutes.
Rho measurements and assessment of Vc and were performed in each patient before and after CPB. Results are summarized in Table 2. Rho decreased significantly after CPB as expected because of hemodilution. Mean values of Vc and were not significantly altered after CPB but showed a substantial interindividual variability.
|
Measurements were obtained in each patient before and after CPB. Figure 2 shows typical steady-state volume, pressure, and dP/dt signals and pressure-volume loops. Systolic and diastolic pressure-volume relations (ESPVR, EDP-volume relation [EDPVR], PRSW, and dP/dtMAX-EDV) in the same patient derived from pressure-volume loops during caval vein occlusion are shown in Figure 3. All patients had sinus rhythm and were paced at 80–90 bpm during measurements. Hemodynamic data are summarized in Table 3: only EDP, Tau, and CS changed significantly after CPB.
|
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Assessment of perioperative ventricular function during cardiac surgery is complicated by the potential occurrence of substantial changes in loading conditions. Therefore, the quantification of systolic and diastolic function requires load-independent indices that can be determined from ventricular pressure-volume relations as obtained by the conductance catheter. Accordingly, the purpose of this study was twofold: we evaluated methodological aspects of perioperative application of the conductance catheter and documented changes of various indices of LV function after CPB in patients undergoing CABG.
Previous studies have extensively shown that the conductance catheter can be applied to obtain pressure-volume relationships. Although most patient studies were performed in the catheterization laboratory, several groups have demonstrated feasibility of the technique in the operating room under various conditions (12–14). Consistent with these previous studies, our study demonstrates that perioperative pressure-volume measurements by the conductance catheter can be used to quantify detailed intrinsic systolic and diastolic function within an acceptable time window. Measurements were uncomplicated, and there were no technical difficulties during instrumentation, catheter placement and loading interventions.
New technical aspects of our study were the use of retrograde insertion of the conductance catheter by using TEE guidance compared with the transmitral approach used in previous studies in the operating room. Both approaches may have theoretical advantages and disadvantages. The transaortic approach provides a better match of the catheter position with the LV long axis. Compared with the anterograde placement, this provides a better registration of the volume changes, especially in the basal segments. In contrast, anterograde placement through the mitral valve may complicate interpretation of segmental volume signals because of changes in the mitral valve plane during ejection and filling. Conversely, with retrograde placement, eccentric (anteromedial) displacement of the catheter at the base of the heart may occur. The electric field is such that the measurement electrodes will move approximately parallel to the equipotential planes field, and thus the eccentric movement is unlikely to strongly influence the conductance signal. Another reason for using the transaortic approach is that we aim to apply this methodology in future studies to evaluate the effects of mitral valve surgery, in which case placement through the aortic valve is clearly preferable. Furthermore, we analyzed the changes in the calibration factors. As a disadvantage, substantial between-patient variability was found for calibration factors (rho, , and Vc), indicating the need for careful assessment of these factors in each individual patient. In addition, after CPB, rho and, to a lesser extent, and Vc were changed because of reduced hematocrit, fluid shifts, and possibly altered catheter position with reinsertion. Although the average and Vc were not significantly changed, substantial differences were present in individual patients, indicating that reassessment is required at the various stages of surgery. Besides influencing between- and within-patient variability, the calibration factors are important for determining the absolute accuracy of the conductance-derived volumes.
Calibration factors and Vc are both obtained by means of indicator-dilution methods: thermodilution and saline dilution, respectively. Thermodilution is widely used in the surgical setting, and the accuracy is generally found to be acceptable (15). In this study, we used "stat" continuous CO measurements with a thermal filament catheter that has accuracy comparable to that of the bolus injection method (16,17). The saline dilution method has been used extensively to obtain parallel conductance and was found to be accurate, with a slight tendency to underestimate the parallel conductance obtained by alternative methods (18). An important advantage of these indicator-dilution methods, compared with imaging modalities such as TEE, is that they do not require assumptions regarding the geometry of the ventricle. This may be relevant especially when comparing conditions in which geometrical changes would be anticipated, such as after ventricular reconstruction or mitral valve surgery. Furthermore, the inter- and intraobserver variability of indicator-dilution methods is limited.
Our main physiological findings were that systolic function was unchanged after CPB in these patients undergoing CABG, whereas early relaxation was improved and diastolic stiffness was increased. Previous pressure-volume studies comparing pre- and post-CPB cardiac function in patients undergoing CABG have shown conflicting data. Schreuder et al. (13) reported unchanged systolic function and increased diastolic stiffness, whereas Wallace et al. (14) found a decrease in systolic function but no changes in relaxation or diastolic stiffness. Both studies used cold cardioplegia, whereas our study was performed with warm-blood cardioplegic arrest, which may explain the preserved systolic function in our study as compared with the decrease found by Wallace et al. The unchanged systolic function found by Schreuder et al. may be attributed to their pre-CPB measurement being obtained at a temperature that was decreased to less than 35°C, which, according to a recent study, significantly reduces Ees by approximately 50% (19). Because the post-CPB measurements in Schreuder et al.’s study were performed at 37°C, this may have masked an actual reduction in systolic function.
With regard to diastolic function, all studies report an increase in diastolic stiffness, although in Wallace et al.’s study (14) this effect did not reach statistical significance. Also in the study of Schreuder et al. (13), the increase was less pronounced as compared with our study (39% increase versus 138%). However, Schreuder et al. described the EDPVR as linear, whereas we derived the diastolic stiffness constant from an exponential relation. The increase is most likely due to myocardial edema after CPB, because myocardial lymph flow has been shown to almost cease during cardioplegic arrest (20). De Hert et al. (21) have shown that a more rapid normalization of diastolic stiffness may be obtained by optimizing preload conditions before weaning from CPB. Furthermore, Allen et al. (22) demonstrated that increasing contractility by dobutamine infusion enhanced myocardial lymphatic function, thus speeding edema removal after CPB. Thus, when difficulty is encountered in weaning from CPB because of increased diastolic stiffness, inotropic support should be considered. However, it should be used with caution because it may adversely affect energetics, increase HR, and induce ischemia (23). In addition, several pharmacological substances added to the cardioplegia composition are associated with reduced edema formation (24–26). Remarkably, although diastolic stiffness was increased, early relaxation was improved in our study, as shown by the significantly reduced Tau. After revascularization, enhanced oxygen-dependent reuptake of calcium into the sarcoplasmic reticulum would be expected to improve active relaxation (27). Our findings are consistent with the results of Humphrey et al. (28), who demonstrated a reduced Tau after CPB in patients undergoing CABG. In contrast, De Hert et al. (21) found an increased Tau in a similar patient group. Differences may be due to the applied anesthetic and cardioplegic protocols that influence post-CPB relaxation directly or indirectly via changes in contractility or loading, which are tightly coupled with relaxation (23,29). Thus, unchanged or even increased Tau as found in some studies may be related to post-CPB changes in systolic function and/or loading conditions. In our study, EDV, ESP, dP/dtMAX, and Ees were not significantly altered after CPB, whereas De Hert et al. (21) reported a reduced dP/dtMAX, indicating a reduced contractile state.
As an alternative to invasive volume measurements, several groups have used TEE to obtain on-line area determination (30–33). This method is less invasive, but when used to construct pressure-area loops, it still requires a LV catheter for pressure measurements, and a loading intervention. Schmidlin et al. (33) tested whether pressure-area relations may be used as a surrogate for pressure-volume relations to detect changes in contractile state, and they concluded that pressure-area analysis provides the same changes as pressure-volume analysis. However, the calculations derived from area estimates have several limitations. During the cardiac cycle, through-plane motion of the LV complicates volume calculations when using short-axis area estimates. This effect is even more prominent during acute loading interventions. In contrast, the intraventricular placement of the conductance catheter provides on-line volume measurements of nearly the entire ventricle unaffected by translations or rotations of the heart within the thorax. In general, on-line area determination by TEE requires optimal image quality, and the stability and reproducibility of measurements are better at higher preload conditions because the effects of tracing errors are minimized (31). Area estimates derived during caval vein occlusion could become very small, thereby decreasing the precision of the digital echocardiographic quantification method for calculation of pressure-area relations. In addition, the precision is reduced in the presence of regional wall motion abnormalities (30). Conventional assessment of diastolic function by TEE (i.e., without simultaneous LV pressure measurement) has two disadvantages compared with the conductance-catheter method. First, assessment of both active and passive components requires two separate TEE views: the midpapillary esophageal long-axis view and transgastric short-axis view, respectively (32). Second, the active diastolic relaxation measured by mitral Doppler flow analysis is HR and load dependent.
In conclusion, the limitations of TEE are outweighed by its proven clinical value to visualize the endoventricular wall and to quantify segmental wall motion. Conversely, the important value of the conductance catheter is that it yields accurate, load-independent quantitative data on basic systolic and diastolic function. The possibility to measure these fundamental quantities in addition to the data provided by TEE may prove to be important in selected patient groups to evaluate new surgical techniques or anesthetic drugs or procedures. The physiological effects on systolic and diastolic function reported in this study will be useful reference data for future studies in patients with depressed LV function undergoing cardiac surgery.
|
Acknowledgments |
|---|
We want to thank Roy L. E. Derikx for his participation in the data analysis.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
- Baan J, van der Velde ET, de Bruin HG, et al. Continuous measurement of left ventricular volume in animals and humans by conductance catheter. Circulation 1984; 70: 812–23.
[Abstract/Free Full Text] - Kass DA, Maughan WL, Guo ZM, et al. Comparative influence of load versus inotropic states on indexes of ventricular contractility: experimental and theoretical analysis based on pressure-volume relationships. Circulation 1987; 76: 1422–36.
[Abstract/Free Full Text] - Bovill JG, Sebel PS, Blackburn CL, et al. The pharmacokinetics of sufentanil in surgical patients. Anesthesiology 1984; 61: 502–6.[Web of Science][Medline]
- Coetzee JF, Glen JB, Wium CA, Boshoff L. Pharmacokinetic model selection for target controlled infusions of propofol: assessment of three parameter sets. Anesthesiology 1995; 82: 1328–45.[Web of Science][Medline]
- Minto CF, Schnider TW, Shafer SL. Pharmacokinetics and pharmacodynamics of remifentanil. II. Model application. Anesthesiology 1997; 86: 24–33.[Web of Science][Medline]
- Steendijk P, van der Velde ET, Baan J. Left ventricular stroke volume by single and dual excitation of conductance catheter in dogs. Am J Physiol 1993; 264: H2198–207.
- Suga H, Sagawa K, Shoukas AA. Load independence of the instantaneous pressure-volume ratio of the canine left ventricle and effects of epinephrine and heart rate on the ratio. Circ Res 1973; 32: 314–22.
[Abstract/Free Full Text] - Little WC, Cheng CP, Peterson T, Vinten-Johansen J. Response of the left ventricular end-systolic pressure-volume relation in conscious dogs to a wide range of contractile states. Circulation 1988; 78: 736–45.
[Abstract/Free Full Text] - Glower DD, Spratt JA, Snow ND, et al. Linearity of the Frank-Starling relationship in the intact heart: the concept of preload recruitable stroke work. Circulation 1985; 71: 994–1009.
[Abstract/Free Full Text] - Little WC. The left ventricular dP/dtmax-end-diastolic volume relation in closed-chest dogs. Circ Res 1985; 56: 808–15.
[Abstract/Free Full Text] - Fransen EJ, Diris JH, Maessen JG, et al. Evaluation of "new" cardiac markers for ruling out myocardial infarction after coronary artery bypass grafting. Chest 2002; 122: 1316–21.
[Abstract/Free Full Text] - Al Khalidi AH, Townend JN, Bonser RS, Coote JH. Validation of the conductance catheter method for measurement of ventricular volumes under varying conditions relevant to cardiac surgery. Am J Cardiol 1998; 82: 1248–52.[Web of Science][Medline]
- Schreuder JJ, Biervliet JD, van der Velde ET, et al. Systolic and diastolic pressure-volume relationships during cardiac surgery. J Cardiothorac Vasc Anesth 1991; 5: 539–45.[Medline]
- Wallace A, Lam HW, Nose PS, et al. Changes in systolic and diastolic ventricular function with cold cardioplegic arrest in man: the Multicenter Study of Perioperative Ischemia (McSPI) Research Group. J Card Surg 1994; 9: 497–502.[Web of Science][Medline]
- Stetz CW, Miller RG, Kelly GE, Raffin TA. Reliability of the thermodilution method in the determination of cardiac output in clinical practice. Am Rev Respir Dis 1982; 126: 1001–4.[Web of Science][Medline]
- Singh A, Juneja R, Mehta Y, Trehan N. Comparison of continuous, stat, and intermittent cardiac output measurements in patients undergoing minimally invasive direct coronary artery bypass surgery. J Cardiothorac Vasc Anesth 2002; 16: 186–90.[Web of Science][Medline]
- Sun Q, Rogiers P, Pauwels D, Vincent JL. Comparison of continuous thermodilution and bolus cardiac output measurements in septic shock. Intensive Care Med 2002; 28: 1276–80.[Web of Science][Medline]
- Steendijk P, Staal E, Jukema JW, Baan J. Hypertonic saline method accurately determines parallel conductance for dual-field conductance catheter. Am J Physiol Heart Circ Physiol 2001; 281: H755–63.
[Abstract/Free Full Text] - Lewis ME, Al Khalidi AH, Townend JN, et al. The effects of hypothermia on human left ventricular contractile function during cardiac surgery. J Am Coll Cardiol 2002; 39: 102–8.
[Abstract/Free Full Text] - Mehlhorn U, Geissler HJ, Laine GA, Allen SJ. Myocardial fluid balance. Eur J Cardiothorac Surg 2001; 20: 1220–30.
[Abstract/Free Full Text] - De Hert SG, ten Broecke PW, Mertens E, et al. Sevoflurane but not propofol preserves myocardial function in coronary surgery patients. Anesthesiology 2002; 97: 42–9.[Web of Science][Medline]
- Allen SJ, Geissler HJ, Davis KL, et al. Augmenting cardiac contractility hastens myocardial edema resolution after cardiopulmonary bypass and cardioplegic arrest. Anesth Analg 1997; 85: 987–92.[Abstract]
- Zile MR, Brutsaert DL. New concepts in diastolic dysfunction and diastolic heart failure. II. Causal mechanisms and treatment. Circulation 2002; 105: 1503–8.
[Free Full Text] - Jayawant AM, Stephenson ER Jr, Damiano RJ Jr. 2,3-Butanedione monoxime cardioplegia: advantages over hyperkalemia in blood-perfused isolated hearts. Ann Thorac Surg 1999; 67: 618–23.
[Abstract/Free Full Text] - Kevelaitis E, Oubenaissa A, Peynet J, et al. Preconditioning by mitochondrial ATP-sensitive potassium channel openers: an effective approach for improving the preservation of heart transplants. Circulation 1999; 100: II345–50.
- Tritto FP, Inserte J, Garcia-Dorado D, et al. Sodium/hydrogen exchanger inhibition reduces myocardial reperfusion edema after normothermic cardioplegia. J Thorac Cardiovasc Surg 1998; 115: 709–15.
[Abstract/Free Full Text] - Halow JM, Figueredo VM, Shames DM, et al. Role of slowed Ca(2+) transient decline in slowed relaxation during myocardial ischemia. J Mol Cell Cardiol 1999; 31: 1739–48.[Web of Science][Medline]
- Humphrey LS, Topol EJ, Rosenfeld GI, et al. Immediate enhancement of left ventricular relaxation by coronary artery bypass grafting: intraoperative assessment. Circulation 1988; 77: 886–96.
[Abstract/Free Full Text] - Brutsaert DL, Sys SU, Gillebert TC. Diastolic dysfunction in post-cardiac surgical management. J Cardiothorac Vasc Anesth 1993; 7: 18–20.[Medline]
- De Hert SG, Rodrigus IE, Haenen LR, et al. Recovery of systolic and diastolic left ventricular function early after cardiopulmonary bypass. Anesthesiology 1996; 85: 1063–75.[Web of Science][Medline]
- Gorcsan J III, Gasior TA, Mandarino WA, et al. Assessment of the immediate effects of cardiopulmonary bypass on left ventricular performance by on-line pressure-area relations. Circulation 1994; 89: 180–90.
[Abstract/Free Full Text] - Houltz E, Hellstrom A, Ricksten SE, et al. Early effects of coronary artery bypass surgery and cold cardioplegic ischemia on left ventricular diastolic function: evaluation by computer-assisted transesophageal echocardiography. J Cardiothorac Vasc Anesth 1996; 10: 728–33.[Web of Science][Medline]
- Schmidlin D, Aschkenasy S, Vogt PR, et al. Left ventricular pressure-area relations as assessed by transoesophageal echocardiographic automated border detection: comparison with conductance catheter technique in cardiac surgical patients. Br J Anaesth 2000; 85: 379–88.
[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
 |
|
  E. A. ten Brinke, R. J. Klautz, S. A. Tulner, F. H. Engbers, H. F. Verwey, D. E. Atsma, M. J. Schalij, E. E. van der Wall, J. J. Bax, H. Putter, et al. Haemodynamics and left ventricular function in heart failure patients: Comparison of awake versus intra-operative conditions Eur J Heart Fail, May 1, 2008; 10(5): 467 - 474. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A.F. Tulner, P. Steendijk, R. J.M. Klautz, J. J. Bax, M. J. Schalij, E. E. van der Wall, and R. A.E. Dion Surgical ventricular restoration in patients with ischemic dilated cardiomyopathy: Evaluation of systolic and diastolic ventricular function, wall stress, dyssynchrony, and mechanical efficiency by pressure-volume loops. J. Thorac. Cardiovasc. Surg., September 1, 2006; 132(3): 610 - 620. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. A.F. Tulner, P. Steendijk, R. J.M. Klautz, J. J. Bax, M. I.M. Versteegh, E. E. van der Wall, and R. A.E. Dion Acute hemodynamic effects of restrictive mitral annuloplasty in patients with end-stage heart failure: Analysis by pressure-volume relations J. Thorac. Cardiovasc. Surg., July 1, 2005; 130(1): 33 - 40. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A.F. Tulner, R. J.M. Klautz, F. H.M. Engbers, J. J. Bax, J. Baan, E. E. van der Wall, R. A.E. Dion, and P. Steendijk Left ventricular function and chronotropic responses after normothermic cardiopulmonary bypass with intermittent antegrade warm blood cardioplegia in patients undergoing coronary artery bypass grafting Eur. J. Cardiothorac. Surg., April 1, 2005; 27(4): 599 - 605. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Steendijk, S. A.F. Tulner, M. Wiemer, R. A. Bleasdale, J. J. Bax, E. E. van der Wall, J. Vogt, and M. J. Schalij Pressure-volume measurements by conductance catheter during cardiac resynchronization therapy Eur. Heart J. Suppl., August 1, 2004; 6(suppl_D): D35 - D42. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. G. de Hert, P. J. Van der Linden, S. A. F. Tulner, R. J. M. Klautz, G. L. van Rijk-Zwikker, F. H. M. Engbers, J. J. Bax, J. Baan, E. E. van der Wall, R. A. Dion, et al. Left Ventricular Function After Cardiopulmonary Bypass Is Related to the Length-Dependent Regulation of Myocardial Function * Response Anesth. Analg., July 1, 2004; 99(1): 311 - 312. [Full Text] [PDF]
|
|
|
|
 |
|
 P. Steendijk, S. A. F. Tulner, J. J. Schreuder, J. J. Bax, L. van Erven, E. E. van der Wall, R. A. E. Dion, M. J. Schalij, and J. Baan Quantification of left ventricular mechanical dyssynchrony by conductance catheter in heart failure patients Am J Physiol Heart Circ Physiol, February 1, 2004; 286(2): H723 - H730. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. B. Moreno, S. Margraf, A. M Schuller, A Simon, A Moritz, and M Scholz Inhibition of neutrophil activity in cardiac surgery with cardiopulmonary bypass: a novel strategy with the leukocyte inhibition module Perfusion, January 1, 2004; 19(1): 11 - 16. [Abstract] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
