Bolus Thermodilution Method Research Articles

Sex-differences in ANOCA patients undergoing invasive coronary function testing: preliminary results from the Dutch national NL-CFT registry

Abstract Background The majority of patients with angina and non-obstructive coronary arteries (ANOCA) are women. In most of these patients coronary vasomotor dysfunction, consisting of coronary vasospasm and coronary microvascular dysfunction (CMD), are identified through invasive coronary function testing (CFT). To acknowledge possible sex differences in clinical characteristics and in the entities of coronary vasomotor dysfunction more data are needed. Therefore, this study presents data from one centre participating in the Dutch national CFT (NL-CFT) registry in order to investigate sex differences in patients with a clinical indication for CFT. Methods This retrospective cohort study included 285 consecutive ANOCA patients undergoing clinically indicated CFT, using the Doppler wire or the bolus thermodilution method, from November 2016 till June 2023. CFT consisted of incremental doses of intracoronary acetylcholine (ACh) for the diagnosis of coronary vasospasm and intracoronary adenosine for the diagnosis of CMD defined as abnormal coronary flow reserve (CFR) and/or microvascular resistance (MR). Results In total, 285 patients of which 233 (82%) women and 52 (18%) men were included. Women were significantly younger (56 vs 59 yrs.; p=0.046), had less diabetes (6% vs 23% p<0.001), less prior PCI (12% vs 27%; p=0.019) and less statin use (39% vs 60%; p=0.006), and more often migraine at some point in their life (38% vs 9%; p<0.001). The prevalence of coronary vasomotor dysfunction (77% vs 65%, p=0.086), epicardial spasm (26% vs 31%, p=0.500), microvascular spasm (35% vs 23%, p=0.104), and CMD (35% vs 27%, p=0.304), was not significantly different between women and men. However, a trend was seen towards a higher prevalence of coronary vasomotor dysfunction, microvascular spasm and CMD in women. In total, 29% of women had an abnormal CFR compared to 16% of men (p=0.065) and an abnormal MR was seen in 11% of women and 12% of men (p=0.938). Cardiovascular risk factors were similar between women and men with epicardial spasm. In patients with microvascular spasm women had less prior PCI (p=0.025) and more migraine (p=0.005), in CMD patients women had less diabetes (p=0.002) and hypercholesterolemia (p=0.044) and more migraine (p=0.006). Conclusion In the NL-CFT registry study including ANOCA patients with a clinical indication for CFT women were younger, had less prior PCI and, diabetes and more often migraine. A trend towards a higher prevalence of coronary vasomotor dysfunction, microvascular spasm and CMD was found in women. Furthermore, our results suggest that men with CMD or microvascular spasm have a different cardiovascular risk profile compared to women, which might suggest different optimal tailored treatment for men compared to women. * Upon acceptance for presentation at the ESC Congress, all patients from the Dutch NL-CFT registry will be incorporated into this analysis, resulting in a study population of approximately 1200 individuals.

ERBB4 activation prevents microvascular dysfunction in a large animal model of hypertensive heart disease

Abstract Background Coronary microvascular dysfunction (CMD) participates in the pathophysiology of multiple cardiovascular diseases, but treatment options are limited. A new treatment option may include ERBB4 stimulation by neuregulin-1 (NRG1), which has anti-inflammatory, antifibrotic, and cardioprotective effects in models of heart failure. Objectives To assess the effect NRG1/ERBB4 stimulation on CMD in hypertensive heart disease. Methods Hypertensive heart disease was induced in 12 Aachener minipigs by implantation of deoxycorticosterone acetate (DOCA) pellets for 8 weeks and compared to 6 controls. The DOCA pigs were randomized to a weekly infusion of JK07, a NRG1 fusion protein with improved pharmacokinetic and pharmacodynamic properties, or vehicle. Microvascular resistance was measured using the bolus thermodilution method. Results DOCA significantly increased microvascular resistance compared to controls (from 14.5 to 19.9 mmHg.s, p = 0.028). This increase was abrogated by JK07 (11.3 mmHg.s, p = 0.018 vs DOCA). dP/dtmax increased by DOCA compared to controls (from 2415.5 to 4455.5 mmHg/s, p = 0.011), which was also abrogated by JK07 (3107.3 mmHg/s, p = 0.055 vs DOCA). Interstitial left ventricular fibrosis was significantly lower in JK07-treated pigs compared to DOCA only (2.1 vs. 5.4 %, p = 0.026), but without difference in perivascular fibrosis (p = 0.48). JK07 did not affect myocyte cross-sectional area, capillary density, pericyte coverage, or microvascular vessel thickness. Conclusions ERBB4 activation by JK07 is capable to prevent CMD in a DOCA hypertensive pig model. Functional rather than structural alterations may explain the protective effects of JK07 on microvascular resistance.Visual summaryJK07 decreases microvascular resistance

Functional improvement of non-infarct related coronary artery stenosis by extensive LDL-C reduction with a PCSK9 antibody: the FITTER trial, microvascular function analysis

Abstract Background Atherosclerosis and microvascular dysfunction are closely linked. Moreover, impaired microvascular function is strongly associated with increased risk on major adverse cardiac events. In patients presenting with acute coronary syndrome (ACS), microvascular function is reduced. PCSK9-inhibitors have shown to reduce plaque burden and lipid load in epicardial vessels and might exhibit similar results on microvascular vessels, thereby improving microvascular function. The FITTER trial offers the unique opportunity to test this hypothesis. Methods The FITTER trial is a multi-center, randomized, double blind, placebo controlled clinical trial for patients presenting with ACS and multi-vessel disease (MVD). After treatment of the culprit lesion, fractional flow reserve (FFR) measurement of non-infarct related artery (non-IRA) lesions was performed. Patients with intermediate, non-critical lesions (FFR: 0.67-0.85) were included in this trial. For exploratory purpose, additional physiological assessment of the non-IRA included coronary flow reserve (CFR) and microvascular resistance index (IMR) measurements. Microvascular function was evaluated using a pressure- and temperature-sensitive guidewire and a bolus thermodilution method. Participants were randomized and treated for 12 weeks with either evolocumab or placebo in addition to high-intensity statin therapy. Staged reevaluation was done at 12 weeks. After repeated physiology testing, PCI was performed if deemed necessary. Pre-defined exploratory analysis includes the absolute and relative difference in change between CFR and IMR from baseline to follow up in the non-IRA. PCSK9 inhibition might result in a relatively larger increase of CFR and larger decrease of IMR. Results Between March 2020 and August 2023, a total of 150 patients were included in the trial. In 61 patients (88.5% male, age 65.3 ± 9.1 years, 23.0% STEMI, 70.5% non-STEMI, 6.6% UAP) successful baseline and follow-up measurements of microvascular function were performed. Complete results will be available at the beginning of March 2024. The primary- and secondary endpoints will be submitted for late-breaking clinical trials selection. The results of this abstract will include a per vessel analysis of coronary artery microvascular function. Conclusion The FITTER trial will provide new insights on the potential of extensive LDL-C reduction with a PCSK9 antibody on microvascular coronary artery function in patients presenting with ACS and MVD.

Predictors of microvascular spasm by spasm provocation testing in patients having angina with no obstructive coronary arteries

Abstract Background Microvascular dysfunction in patients having angina with no obstructive coronary arteries (ANOCA) has been recognized to be associated with poor prognosis, while microvascular spasm (MVS) has not been fully studied due to its diagnostic challenge. Purpose We aimed to explore clinical and coronary physiological characteristics of MVS. Methods We retrospectively studied patients with ANOCA who underwent spasm provocation test (SPT) with intracoronary acetylcholine administration followed by coronary physiological assessment. Epicardial spasm and MVS were diagnosed in accordance with the latest guideline. Physiological indices such as coronary flow reserve (CFR), index of microcirculatory resistance (IMR) and microvascular resistance reserve (MRR) were assessed by bolus thermodilution method using pressure temperature wire in LAD and RCA. Results In a total of 141 patients, 40 (28.4%) patients were diagnosed as epicardial spasm and 22 (15.6%) were diagnosed as MVS according to the diagnostic criteria of the latest guideline. Women was more frequent (63.9% vs 27.3%, P=0.002) and IMR of LAD was significantly higher (34.80 vs 22.95, P=0.005) in patients with versus without MVS. In addition, hypertension tended to be frequent (81.8% vs 60.5%, P=0.089) in patients with MVS. In a multivariable logistic regression analysis, women (odds ratio 5.64 [OR], 95% CI 1.90 – 16.7, P=0.0018) and IMR of LAD (OR 1.02, 95% CI 1.00 – 1.05, P=0.029) were independently associated with the diagnosis of MVS. On the other hand, no clinical characteristics and physiological parameter were significantly associated with epicardial spasm. In a comparison between microvascular and epicardial spasm, women (OR 8.30, 95%CI 2.23 – 30.9, P=0.0016) and IMR of LAD (OR 1.04, 95%CI 1.00 – 1.08, P=0.0462) were still significantly more frequent in MVS patients in multivariable analysis. Conclusion Women and higher IMR of LAD were significantly frequent in patients with versus without MVS, and hypertension tended to be frequent in MVS patients.

Impact of microvascular resistance reserve on post-STEMI cardiac remodelling and diastolic function

Abstract Background Coronary microvascular dysfunction (CMD) is a common sequelae of ST-segment elevation myocardial infarction (STEMI), preventing adequate recovery of left ventricular (LV) perfusion. The interferences of con-commitment epicardial stenosis or hyperemic hemodynamic alterations limit traditional physiologic metrics. The microvascular resistance reserve (MRR) was developed to overcome these shortcomings. Purpose We aim to investigate the association between post-STEMI MRR, and the ensuing left ventricle (LV) diastolic dysfunction, and functional remodeling. Methods In this prospective, observational study, we enrolled STEMI patients with multivessel disease who successfully underwent primary percutaneous coronary intervention (PCI). At three months post-PCI, all patients received complete revascularization followed by coronary physiology assessment using the bolus thermodilution method to measure the fractional flow reserve (FFR), coronary flow reserve (CFR), and the index of microcirculatory resistance (IMR). MRR was calculated using the formula: MRR = (CFR/FFR) × (Pa rest/Pa hyper), where Pa rest and Pa hyper represent resting and hyperemic aortic pressure, respectively(1). CMD was defined as an MRR < 3.0 based on Boerhout et al(2). Diastolic dysfunction was defined according to the ASE 2016 guidelines. Functional LV remodelling (FLVR) was categorized according to Chimed et al(3). The relationship between CMD and the stages of FLVR and diastolic dysfunction was scrutinized over a 12-month follow-up period. Results We enrolled 210 patients, of whom 125 (59.5%) were men with a median age of 65 (IQR: 58–76). At the 3-month follow-up, the MRR was 3.46 (IQR 3.00, 3.92), with 56 (26.7%) patients having CMD (MRR<3.0). MRR is significantly correlated with the change of LVEF between primary PCI and 12 months (r=0.48, p<0.001, Fig1A). CMD patients have lower LVEF at 12 months (50.00% vs. 40.00%; p < 0.001) and demonstrated significantly less recovery in LV systolic function (-10.00% vs. 8.00%; p < 0.001, Fig 1B, 1C). CMD patients had a higher prevalence of grade 2 or 3 LV diastolic dysfunction (65.38% vs. 3.95%; p < 0.001, Fig 2A) and a higher incidence of advanced FLVR (Groups 3 and 4) compared to those without CMD (30.77% vs. vs. 10.53%; p < 0.001, Fig 2B). In multivariable logistic regression analysis, MRR was independently associated with LV diastolic dysfunction (0.17, 95%CI 0.08-0.33, p<0.001). Conclusions The novel parameter MRR is significantly related to LVEF recovery in STEMI patients and is an independent predictor for advanced LV diastolic dysfunction and FLVR. CMD patients, as diagnosed with MRR, showed a higher prevalence of advanced FLVR and diastolic dysfunction. These results suggest that MRR is a useful parameter for the identification and management of CMD in STEMI patients.

Prognostic Value of Microvascular Resistance Reserve Measured Immediately After PCI in Stable Coronary Artery Disease.

Microvascular resistance reserve (MRR) has been proposed as a specific metric to quantify coronary microvascular function. The long-term prognostic value of MRR measured in stable patients immediately after percutaneous coronary intervention (PCI) is unknown. This study sought to determine the prognostic value of MRR measured immediately after PCI in patients with stable coronary artery disease. This study included 502 patients with stable coronary artery disease who underwent elective PCI and coronary physiological measurements, including pressure and flow estimation using a bolus thermodilution method after PCI. MRR was calculated as coronary flow reserve divided by fractional flow reserve times the ratio of mean aortic pressure at rest to that at maximal hyperemia induced by hyperemic agents. An abnormal MRR was defined as ≤2.5. Major adverse cardiac events (MACEs) were defined as a composite of all-cause mortality, any myocardial infarction, and target-vessel revascularization. During a median follow-up of 3.4 years, the cumulative MACE rate was significantly higher in the abnormal MRR group (12.5 versus 8.3 per 100 patient-years; hazard ratio 1.53 [95% CI, 1.10-2.11]; P<0.001). A higher all-cause mortality rate primarily drove this difference. On multivariable analysis, a higher MRR value was independently associated with lower MACE and lower mortality. When comparing 4 subgroups according to MRR and the index of microcirculatory resistance, patients with both abnormal MRR and index of microcirculatory resistance (≥25) had the highest MACE rate. An abnormal MRR measured immediately after PCI in patients with stable coronary artery disease is an independent predictor of MACE, particularly all-cause mortality.

C-29 | Utility of invasive bolus thermodilution method in diagnosis of coronary microvascular dysfunction (CMD): Real World data

C-29 | Utility of invasive bolus thermodilution method in diagnosis of coronary microvascular dysfunction (CMD): Real World data

Agreement between direct Fick and bolus thermodilution measurements of cardiac output during right heart catheterisation and the impact on haemodynamic classifications

Abstract Background/Introduction When measuring cardiac output (CO) during right heart catheterisation (RHC), both direct Fick (DF) and bolus thermodilution (TD) methods are endorsed by pulmonary hypertension (PH) guidelines (1). Agreement between these techniques in contemporary practice is not well understood, nor are the diagnostic consequences of disagreement. Purpose To investigate the real-world agreement between DF and TD techniques for measuring CO during contemporary RHC, and evaluate the impact of disagreement on patients’ haemodynamic classification. Methods This was a single-centre study including 182 patients who had CO measured simultaneously by DF and TD methods during RHC. Oxygen consumption (VO2) was measured with an indirect calorimeter. The primary outcome was the agreement between DF and TD derived CO using Bland-Altman analysis. Secondary outcomes included the impact of specific clinical variables on CO agreement, and the frequency of disagreement in determining patients’ haemodynamic classification. Results Disagreement between DF and TD measures of CO was noted, with the DF technique tending to overestimate CO relative to the TD measurement (median DF-CO 5.42 L/min [interquartile range (IQR) 3.90 – 7.41] vs median TD-CO 4.10 L/min [IQR 3.47 – 5.10], p&amp;lt;0.001). For CO values between 3-7 L/min, the error between DF and TD measurements ranged from -4.75% to +44.5%, and limits of agreement were between -69.9% and +101% (Figure 1). Disagreement was increased by 19.2% in patients with at least moderate-to-severe tricuspid regurgitation, and by 16.0% in those with irregular heart rhythms (Table1). The agreement between DF and TD derived pulmonary vascular resistance (PVR) was equally poor. Nonetheless, in 86.3% of patients, the techniques agreed in classifying the PVR as abnormally elevated (&amp;gt; 2 Wood Units), with disagreement occurring more frequently in patients with less severe PH. Conclusions In this real-world study there was poor agreement between DF and TD derived CO, resulting in more than 10% of patients having discrepant haemodynamic classifications. This data highlight that both methods should be utilised in clinical practice, particularly in borderline cases or when the haemodynamic assessment influences treatment eligibility or operative risk assessment. The two techniques should not be used interchangeably for serial surveillance, and the impact of our findings on invasive assessments of valvular pathologies needs further investigation.

A comparison of ClearSight noninvasive cardiac output and pulmonary artery bolus thermodilution cardiac output in cardiac surgery patients

BackgroundThe ClearSight system measures blood pressure non-invasively and determines cardiac output by analyzing the continuous pressure waveform. We performed a multi-center clinical study in China to test the equivalence of cardiac output measured with the ClearSight system (CSCO) and cardiac output measured with the pulmonary artery catheter bolus thermodilution (TDCO) method.MethodsWe included adult patients undergoing cardiac surgery in three Chinese hospitals and measured TDCO and CSCO simultaneously after induction of anesthesia. Hemodynamic stability was required during measurement of TDCO and CSCO. At least four TDCO determinations were performed. The corresponding CSCO was determined as the average over a 30-s period following the injection of each bolus. A data pair for the comparison included the average of three or four accepted TDCO values and the average of the matching CSCO values. Main outcomes included Bland-Altman analysis of bias and standard deviation (SD) and the percentage error (PE).ResultsOne hundred twenty-five subjects were enrolled, and 122 TDCO and CSCO data pairs were available for analysis. Ninety-five (75.4%) data pairs were collected in hemodynamically stable conditions, mean (SD) CSCO was 4.21 (0.78) l/min, and mean TDCO was 3.90 (0.67) l/min. Bias was 0.32 (0.51) l/min, and PE was 25.2%. Analyzing all 122 data pairs resulted in a mean CSCO of 4.19 (0.82) l/min and a mean TDCO of 3.83 (0.71) l/min. Resulting bias was 0.36 (0.53) l/min, and PE was 26.4%.ConclusionsCSCO and TDCO agreed with a low systematic bias. Besides, mean PE was well below the pre-defined 30%. Hemodynamic stability only had a small impact on the analysis. We conclude that CSCO is equivalent to TDCO in cardiac surgery patients.The trial was retrospectively registered in ClinicalTrials.gov, identifier NCT03807622; January 17, 2019

Ability of a New Smartphone Pulse Pressure Variation and Cardiac Output Application to Predict Fluid Responsiveness in Patients Undergoing Cardiac Surgery.

Pulse pressure variation (PPV) can be used to predict fluid responsiveness in anesthetized patients receiving controlled mechanical ventilation but usually requires dedicated advanced monitoring. Capstesia (Galenic App, Vitoria-Gasteiz, Spain) is a novel smartphone application that calculates PPV and cardiac output (CO) from a picture of the invasive arterial pressure waveform obtained from any monitor screen. The primary objective was to compare the ability of PPV obtained using the Capstesia (PPVCAP) and PPV obtained using a pulse contour analysis monitor (PPVPC) to predict fluid responsiveness. A secondary objective was to assess the agreement and the trending of CO values obtained with the Capstesia (COCAP) against those obtained with the transpulmonary bolus thermodilution method (COTD). We studied 57 mechanically ventilated patients (tidal volume 8 mL/kg, positive end-expiratory pressure 5 mm Hg, respiratory rate adjusted to keep end tidal carbon dioxide [32-36] mm Hg) undergoing elective coronary artery bypass grafting. COTD, COCAP, PPVCAP, and PPVPC were measured before and after infusion of 5 mL/kg of a colloid solution. Fluid responsiveness was defined as an increase in COTD of >10% from baseline. The ability of PPVCAP and PPVPC to predict fluid responsiveness was analyzed using the area under the receiver-operating characteristic curve (AUROC), the agreement between COCAP and COTD using a Bland-Altman analysis and the trending ability of COCAP compared to COTD after volume expansion using a 4-quadrant plot analysis. Twenty-eight patients were studied before surgical incision and 29 after sternal closure. There was no significant difference in the ability of PPVCAP and PPVPC to predict fluid responsiveness (AUROC 0.74 [95% CI, 0.60-0.84] vs 0.68 [0.54-0.80]; P = .30). A PPVCAP >8.6% predicted fluid responsiveness with a sensitivity of 73% (95% CI, 0.54-0.92) and a specificity of 74% (95% CI, 0.55-0.90), whereas a PPVPC >9.5% predicted fluid responsiveness with a sensitivity of 62% (95% CI, 0.42-0.88) and a specificity of 74% (95% CI, 0.48-0.90). When measured before surgery, PPV predicted fluid responsiveness (AUROC PPVCAP = 0.818 [P = .0001]; PPVPC = 0.794 [P = .0007]) but not when measured after surgery (AUROC PPVCAP = 0.645 [P = .19]; PPVPC = 0.552 [P = .63]). A Bland-Altman analysis of COCAP and COTD showed a mean bias of 0.3 L/min (limits of agreement: -2.8 to 3.3 L/min) and a percentage error of 60%. The concordance rate, corresponding to the proportion of CO values that changed in the same direction with the 2 methods, was poor (71%, 95% CI, 66-77). In patients undergoing cardiac surgery, PPVCAP and PPVPC both weakly predict fluid responsiveness. However, COCAP is not a good substitute for COTD and cannot be used to assess fluid responsiveness.

Evaluation of the Fourth-Generation FloTrac/Vigileo System in Comparison With the Intermittent Bolus Thermodilution Method in Patients Undergoing Cardiac Surgery

The aim of this study was to evaluate the accuracy, precision, and trending ability of the fourth-generation FloTrac/Vigileo system (version 4.00; Edwards Lifesciences, Irvine, CA) by comparing cardiac output derived from FloTrac/Vigileo system (COAP) with that measured by a pulmonary artery catheter (COTD), and to determine the effects of hemodynamic variables on the bias between COTD and COAP. A prospective study. University hospital. Thirty patients undergoing elective cardiac surgery using cardiopulmonary bypass. Including hemodynamic variables, COTD and COAP were measured simultaneously at the following 10 time points: after the induction of anesthesia, at the start of operation, after sternotomy, before and after the administration of heparin, before and after the administration of protamine, at the start of sternal closure, at the end of operation, and on arrival to intensive care unit. In total, 280 pairs of datasets were obtained. Bland-Altman analysis showed a bias of -0.41 L/min, a precision of 0.72 L/min, and limits of agreement of -1.85 and 1.03 L/min, with a percentage error of 37.1%. The concordance rate determined by 4-quadrant plot analysis and the polar concordance rate were 76% and 79%, respectively. The linear mixed-effect model revealed that the bias was influenced strongly by the difference in pulse pressure between the radial and femoral artery (p < 0.001), and the systemic vascular resistance index (p < 0.001). The fourth-generation FloTrac/Vigileo system still lacks accuracy and trending ability in cardiac surgery, and the discrepancy in cardiac output measurement depends on the peripheral vascular tone. Further improvement of this system is needed.

Cardiac Output Derived From Arterial Pressure Waveform Analysis: Validation of the Third-Generation Software in Patients Undergoing Orthotopic Liver Transplantation

BackgroundThe upgraded third-generation software (version 3.02) for the FloTrac/Vigileo system has been developed to particularly improve the accuracy of cardiac output (CO) measurements in hyperdynamic conditions. The aim of our study was to compare the CO values obtained using the FloTrac/Vigileo system during orthotopic liver transplantation (OLT) with those obtained in the same circumstances using a Swan-Ganz catheter (bolus thermodilution method). MethodsTwenty consecutive recipients scheduled for OLT were studied. Simultaneous CO values measured by both devices were obtained at 10 predefined time points throughout the surgery. A percentage error of not more than 30% was established as the criterion for device interchangeability. ResultsA total of 200 paired measurements were obtained. The CO values derived from the FloTrac/Viligeo ranged from 2.8 to 10.9 L/min, with a mean of 5.91 ± 1.81 L/min. The values from bolus thermodilution ranged from 2.2 to 13.2 L/min, with a mean of 6.12 ± 2.07 L/min. The bias was 0.22, and the limits of agreement were −3.13 to 3.56 L/min. The percentage error between the FloTrac/Viligeo and bolus thermodilution measurements was 54.93%. The percentage errors of paired measurements in three surgical phases by subgroup analysis were 43.50% (dissecting phase), 62.9% (anhepatic phase), and 56.05% (reperfusion phase), respectively. ConclusionCO measurements obtained using the less invasive arterial waveform FloTrac/Vigileo system upgraded with the third-generation software had poor intraoperative agreement with pulmonary artery thermodilution CO measurements in patients undergoing OLT.

The Accuracy of the Vigileo/FloTrac Continuous Cardiac Output Monitor

The Vigileo/FloTrac system (software version 1.01; Edwards Lifesciences, Irvine, CA) determines cardiac output, without calibration, by analysis of the arterial pulse wave. To assess the accuracy of the Vigileo/FloTrac system, it was compared with the pulmonary artery catheter bolus thermodilution method as the current standard method. The study design was prospective and observer blinded. A single university hospital. Thirty elective coronary artery bypass graft surgery patients. No special interventions were done to the participants. After approval by the ethics committee and with written informed consent, synchronized measurements using both methods were made at 7 predefined time points, intraoperatively and postoperatively, producing 192 data pairs for evaluation. The statistical evaluation was performed by using the Bland-Altman method of analysis. In addition, a +/-20% and +/-30% deviation from the pulmonary artery catheter were evaluated (20% criteria and 30% criteria). In total, 46% of measurements did not fulfill the 20% criteria; 26% were outside the 30% limits. The Bland-Altman analysis for all time points showed that 95% of all differences between both methods were within a range between -2.2 and +3.1 L/min. Regression analysis revealed low correlation values at all time points. The described deviation from the standard must be regarded according to the user's needs. Considering the 30% limits of agreement, the Vigileo system (version 1.01) seems sufficiently accurate; applying the 20% criteria, it is not.

Effects of vasodilation on cardiac output measured by PulseCO™

The instability of cardiac output (CO) measured by PulseCO (LiDCO Ltd.) during cardiac surgery has been reported. In the present study, we investigated the effects of vasodilation by prostaglandin E1 (PGE1) on the relation between cardiac output measured by PulseCO and that by thermodilution. Twenty patients who underwent off-pump coronary artery bypass grafting (OPCAB) were enrolled in this study. After premedication with oral diazepam 10 mg, anesthesia was induced with midazolam, fentanyl and vecuronium. CO was measured after anesthesia induction, at PGE1 0.01, 0.02 and 0.04 microg/(kg min) and at 15 min after the stop of the infusion. Systemic vascular resistances (SVRs) by PGE1 at 0.02 and 0.04 microg/(kg min) were significantly lower than the control value. The correlation coefficient (R2) between the two techniques at each point, percentage error and limits of agreement (bias +/-2SD of bias) were 0.78, 3, 0.05 +/- 0.17 at 0.01 microg/(kg min), 0.20, 10, -0.18 +/- 0.12 at 0.02 microg/(kg min), 0.46, 28, -0.50 +/- 0.24 at 0.04 microg/(kg min) and 0.97, 1, 0.02 +/- 0.27 L/min at 15 min after stop of infusion, respectively. PulseCO might underestimate CO compared to that by bolus thermodilution method when simply decreasing the SVR by infusion of PGE1. Therefore, PulseCO might be unsuitable in cardiac surgery.

Cardiac Output Measured by a New Arterial Pressure Waveform Analysis Method Without Calibration Compared With Thermodilution After Cardiac Surgery

To investigate whether measuring cardiac output and its course after cardiac surgery by a new analysis technique of radial artery pressure waves, without need for calibration (FloTrac/Vigileo [FV]; Edwards Lifesciences, Irvine, CA), conforms to the standard bolus thermodilution method via a pulmonary artery catheter (PAC). Prospective study. Intensive care unit of university hospital. Twenty patients for up to 24 hours after cardiac surgery. Simultaneous and triplicate PAC thermodilution and FV cardiac output measurements at 1 and 3 hours after surgery and the following morning. Fifty-six simultaneous measurement sets were obtained. Mean cardiac output (PAC) ranged between 2.8 and 10.3 L/min and for the FV method between 3.3 and 8.8 L/min. The coefficient of variation for pooled measurements was 7.3% for the PAC and 3.0% for the FV method. For pooled data, the r2 was 0.55 (p < 0.001), with a bias of -0.14, precision of 1.00 L/min, and 95% limits of agreement between -2.14 and 1.87 L/min in a Bland-Altman plot. Also, the FV method tended to overestimate cardiac output when <7 L/min and increased with time, whereas mean arterial pressure increased and PAC cardiac output did not change. Changes in cardiac output correlated (r2 = 0.52, p < 0.001). The FV arterial pressure waveform analysis method is a clinically applicable method for cardiac output assessment without calibration, after cardiac surgery. It performs well at low cardiac outputs but remains sensitive to changes in vascular tone.

Cardiothoracic Anesthesia, Respiration and Airway Cardiac output by PulseCO™ is not interchangeable with thermodilution in patients undergoing OPCAB

To investigate the reliability of cardiac output assessed by arterial pressure waveform (PulseCO) in comparison with bolus thermodilution measurements in patients undergoing off-pump coronary artery bypass grafting (OPCAB).23 patients who underwent OPCAB were enrolled in this study. After premedication with oral diazepam 10 mg, anesthesia was induced with midazolam, fentanyl and vecuronium. After induction, radial artery and pulmonary artery catheters were inserted. Cardiac output was measured simultaneously by the PulseCO and the bolus thermodilution method using the Vigilance monitor: 1) after sternotomy, 2) after opening the mediastinum, and 3) at the end of surgery. The PulseCO was calibrated initially with cardiac output determined by the thermodilution method after induction of anesthesia.The correlation coefficients between the two techniques at the three measurement periods were: 1) R2 = 0.49, 2) R2 = 0.52, 3) R2 = 0.55. The limits of agreement (bias +/- 2 SD of bias) were: 1) 0.71 +/- 2.66, 2) 0.30 +/- 1.97, 3) 0.76 +/- 3.85 L.min(-1).Cardiac output by PulseCO is not interchangeable with cardiac output measured by thermodilution in patients undergoing OPCAB.

Effects of vasodilation cardiac output measured by PulseCOTM

PulseCOTM (LiDCO Ltd, London, UK) is a continuous cardiac output (CO) monitor using the pulse-contour method. The pulse-contour method was defined as the method to determine CO from characteristics of the arterial pressure waveform. However, the arterial pressure waveform often changes during surgery because of the arterial compliance changes using vasoactive drugs. These factors may induce miscalculation of the CO by PulseCOTM. In the present study, we investigated the effects of vasodilation induced by prostaglandin E1 (PGE1) on CO measured by PulseCOTM in comparison with CO measured by the bolus thermodilution method.

Comparação entre a medida contínua do débito cardíaco e por termodiluição em bolus durante a revascularização miocárdica sem circulação extracorpórea

JUSTIFICATIVA E OBJETIVOS: A cirurgia de revascularização miocárdica sem o uso de circulação extracorpórea (CEC) relaciona-se a importantes alterações hemodinâmicas bruscas, que podem não ser prontamente detectadas pela medida contínua de débito cardíaco. Este estudo compara resultados obtidos pela medida do índice cardíaco com o cateter de artéria pulmonar com filamento térmico (Baxter Edwards Critical Care, Irvine, CA) com o método padrão por termodiluição com solução, durante a anastomose coronariana distal. MÉTODO: Dez pacientes submetidos à cirurgia de revascularização miocárdica sem CEC foram monitorizados com o cateter de artéria pulmonar com filamento térmico. As medidas de índice cardíaco foram obtidas em quatro momentos: no início da anestesia, enquanto o tórax ainda estava fechado (M1), após a esternotomia (M2), após a estabilização do coração com o aparelho octopus (M3) e ao final da anastomose coronariana distal (M4). RESULTADOS: Houve diminuição significativa (p < 0,05) do índice cardíaco durante a anastomose coronariana, detectada pela medida com termodiluição com bolus de solução. O índice cardíaco variou de 2,8 ± 0,7 para 2,3 ± 0,8 l.min.m-2 no início da anastomose e 2,5 ± 0,8 l.min.m-2 ao final da mesma. Essa variação não foi detectada pela medida contínua (de 3 ± 0,6 para 3,2 ± 0,5 e 3,1 ± 0,6 l.min.m-2 durante a anastomose coronariana). CONCLUSÕES: A medida de débito cardíaco contínuo utilizando o cateter de artéria pulmonar com filamento térmico apresentou atraso na detecção das alterações hemodinâmicas agudas relacionadas à mudança do posicionamento do coração na cirurgia de revascularização miocárdica sem CEC.

Cardiac output measurement after coronary artery bypass grafting using bolus thermodilution, continuous thermodilution, and whole-body impedance cardiography

Objective: To test the feasibility of continuous cardiac output (CO) monitoring with whole-body impedance cardiography after coronary artery bypass grafting and to compare the values obtained with those measured using the bolus and continuous thermodilution methods. Design: A prospective study. Setting: Intensive care unit in a university hospital. Patients: Twenty patients after coronary artery bypass grafting. Interventions: CO was measured intermittently using the bolus thermodilution method, and continuously using the continuous thermodilution method, and whole-body impedance cardiography immediately after transfer to the intensive care unit. Measurements and Main Results: Bolus thermodilution CO was measured in triplicate at up to 14 time points overnight. Continuous thermodilution CO and whole-body impedance cardiography CO values were recorded simultaneously. During the study period, the bias in CO values between bolus thermodilution and whole-body impedance cardiography ranged from 0.07 to 1.05 L/min and the precision (standard deviation of differences) ranged from 0.82 to 1.31 L/min. The bias between the bolus and continuous thermodilution methods ranged from 0.06 to 0.58 L/min and the precision from 0.43 to 1.02 L/min. Pulmonary artery temperature and CO level were the major determinants of the bias and precision in both comparisons. Conclusions: Agreement between whole-body impedance cardiography and bolus thermodilution is slightly inferior to that between the bolus and continuous thermodilution methods but not to the extent that it hampers the use of whole-body impedance cardiography for the continuous monitoring of CO after coronary artery bypass surgery. © 2003 Elsevier Inc. All rights reserved.

Continuous and intermittent cardiac output measurement: pulmonary artery catheter versus aortic transpulmonary technique

Cardiac output (CO) can be measured intermittently by bolus thermodilution methods in the pulmonary artery (COpa) or in the aorta (COart). A continuous thermodilution method (CCO) and a method for continuous estimation using the arterial pulse wave (PCCO) are also available. We compared two methods of intermittent CO measurements in patients during liver transplantation: COpa, regarded as the current clinical standard, and an aortic transpulmonary thermodilution technique (COart) performed with the PiCCO system. We also compared CCO and PCCO. Measurements were made in 62 patients at three stages: after the induction of anaesthesia, after caval clamping phase, and at the end of surgery. We used Bland-Altman and correlation analysis. We found close agreement between the techniques. Mean bias between COart and COpa and PCCO and CCO was 0.15 (2SD of differences between methods=1.74) litre min(-1) and -0.03 (1.75) litre min(-1), respectively. Mean bias between CCO and COpa and PCCO and COpa was 0.02 (1.48) litre min(-1) and 0.04 (1.69) litre min(-1), respectively. Measurement with the aortic transpulmonary thermodilution technique gives continuous and intermittent values that agree with the pulmonary thermodilution method.