Nilotinib with or without cytarabine for Philadelphia positive acute lymphoblastic leukemia.

We previously demonstrated that a reduced-intensity chemotherapy schedule can safely replace Hyper-CVAD cycle 1 when combined with imatinib in adults with Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). In the present randomized GRAAPH-2014 trial, we used nilotinib and addressed the omission of cytarabine (Ara-C) in consolidation. The primary objective was the major molecular response (MMR) rate measured by BCR::ABL1 quantification after cycle 4 (end of consolidation). All patients were eligible for allogeneic stem cell transplant (SCT), whereas those in MMR could receive autologous SCT, followed by 2-year imatinib maintenance in both cases. After the enrollment of 156 out of 265 planed patients, the data and safety monitoring board decided to hold the randomization due to an excess of relapse in the investigational arm. Among the 155 evaluable patients, 77 received Ara-C during consolidation (arm A) and 78 did not (arm B). Overall, 133 (85%) patients underwent SCT, 93 allogeneic, 40 autologous. The non-inferiority endpoint regarding MMR was reached with 71.1% (arm A) and 77.2% (arm B) of patients reaching MMR. However, the 4-year cumulative incidence of relapse was higher in arm B as compared to arm A (31.3% [95% CI, 21.1-41.9%] versus 13.2% [95% CI, 6.7-21.9%]; p=0.017), which translated in a lower relapse-free survival. With a median follow-up of 3.8 years, 4-year overall survival (OS) was 79.0% (95% CI, 70.6-89.3%) in arm A versus 73.4% (95% CI, 63.9-84.4%) in arm B (p=0.35). Despite a non-inferior rate of MMR, more relapses were observed when ARA-C was omitted without impact on survival. ClinicalTrials.gov ID, NCT02611492.

Transplantation for myelofibrosis patients in the ruxolitinib era: a registry study from the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire.

In this SFGM-TC registry study, we report the results after stem cell transplantation (HSCT) in 305 myelofibrosis patients, in order to determine potential risk factors associated with outcomes, especially regarding previous treatment with ruxolitinib. A total of 102 patients were transplanted from an HLA-matched-sibling donor (MSD), and 143 patients received ruxolitinib. In contrast with previous studies, our results showed significantly worse outcomes for ruxolitinib patients regarding overall survival (OS) and non-relapse mortality (NRM), especially in the context of unrelated donors (URD). When exploring reasons for potential confounders regarding the ruxolitinib effect, an interaction between the type of donor and the use of ATG was found, therefore subsequent analyses were performed separately for each type of donor. Multivariable analyses did not confirm a significant negative impact of ruxolitinib in transplantation outcomes. In the setting of URD, only age and Fludarabine-Melphalan (FM) conditioning were associated with increased NRM. For MSD, only Karnoksfy <70% was associated with reduced OS. However, a propensity score analysis showed that ruxolitinib had a negative impact on OS but only in non-responding patients, consistent with previous data. To conclude, with all the precautions due to confounders and bias, ruxolitinib itself does not appear to increase mortality after HSCT.

Platelet transfusions in haploidentical haematopoietic stem cell allograft candidates: Protecting HLA-A and HLA-B antigens through eplet analysis.

In patients awaiting an allogeneic haematopoietic stem cell transplantation, platelet transfusion is a risk factor for anti-HLA class I immunization because the resulting donor-specific antibodies complicate the allograft process. The objective of the present study was to determine the feasibility of a novel eplet-based strategy for identifying HLA class I mismatches between potential donors and the recipient when pre-allograft platelet transfusions were required. We included 114 recipient/haploidentical relative pairs. For each pair, we entered HLA-class I typing data into the HLA Eplet Mismatch calculator, defined the list of mismatched eplets (for the recipient versus donor direction) and thus identified the shared HLAs to be avoided. Using this list of HLAs, we defined the theoretical availability of platelet components (PCs) by calculating the virtual panel-reactive antibody (vPRA). We also determined the number of PCs actually available in France by querying the regional transfusion centre's database. The mean ± standard deviation number of highly/moderately exposed eplets to be avoided in platelet transfusions was 5.8 ± 3.3, which led to the prohibition of 38.5 ± 2 HLAs-A and -B. Taking into account the mismatched antigens and the eplet load, the mean ± standard deviation theoretical availability of PCs (according to the vPRA) was respectively 34.49% ± 1.95% for HLA-A and 80% ± 2.3% for HLA-B. A vPRA value below 94.9% for highly or moderately exposed eplets would predict that 10 PCs were actually available nationally. Although epitope protection of HLA molecules is feasible, it significantly restricts the choice of PCs.

Nonrelapse mortality after CAR T-cell therapy for large B-cell lymphoma: a LYSA study from the DESCAR-T registry.

CD19 chimeric antigen receptor (CAR) T cells can induce prolonged remissions and potentially cure a significant proportion of patients with relapsed/refractory large B-cell lymphomas. However, some patients may die of causes unrelated to lymphoma after CAR T-cell therapy. To date, little is known about the nonrelapse mortality (NRM) after CAR T-cell therapy. Using the French DESCAR-T registry, we analyzed the incidence and causes of NRM and identified risk factors of NRM. We report on 957 patients who received standard-of-care axicabtagene ciloleucel (n = 598) or tisagenlecleucel (n = 359) between July 2018 and April 2022, in 27 French centers. With a median follow-up of 12.4 months, overall NRM occurred in 48 patients (5.0% of all patients): early (before day 28 after infusion) in 9 patients (0.9% of all patients and 19% of overall NRM), and late (on/after day 28 after infusion) in 39 patients (4.1% of all patients and 81% of overall NRM). Causes of overall NRM were distributed as follows: 56% infections (29% with non-COVID-19 and 27% with COVID-19), 10% cytokine release syndromes, 6% stroke, 6% cerebral hemorrhage, 6% second malignancies, 4% immune effector cell associated neurotoxicities, and 10% deaths from other causes. We report risk factors of early NRM and overall NRM. In multivariate analysis, both diabetes and elevated ferritin level at lymphodepletion were associated with an increased risk of overall NRM. Our results may help physicians in patient selection and management in order to reduce the NRM after CAR T-cell therapy.

Axicabtagene ciloleucel as second-line therapy in large B cell lymphoma ineligible for autologous stem cell transplantation: a phase 2 trial.

Axicabtagene ciloleucel (axi-cel) demonstrated superior efficacy compared to standard of care as second-line therapy in patients with high-risk relapsed/refractory (R/R) large B cell lymphoma (LBCL) considered eligible for autologous stem cell transplantation (ASCT); however, in clinical practice, roughly half of patients with R/R LBCL are deemed unsuitable candidates for ASCT. The efficacy of axi-cel remains to be ascertained in transplant-ineligible patients. ALYCANTE, an open-label, phase 2 study, evaluated axi-cel as a second-line therapy in 62 patients with R/R LBCL who were considered ineligible for ASCT. The primary end point was investigator-assessed complete metabolic response at 3 months from the axi-cel infusion. Key secondary end points included progression-free survival, overall survival and safety. The study met its primary end point with a complete metabolic response of 71.0% (95% confidence interval, 58.1-81.8%) at 3 months. With a median follow-up of 12.0 months (range, 2.1-17.9), median progression-free survival was 11.8 months (95% confidence interval, 8.4-not reached) and overall survival was not reached. There was no unexpected toxicity. Grade 3-4 cytokine release syndrome and neurologic events occurred in 8.1% and 14.5% of patients, respectively. These results support axi-cel as second-line therapy in patients with R/R LBCL ineligible for ASCT. ClinicalTrials.gov Identifier: NCT04531046 .

Impact of central nervous system involvement in adult patients with Philadelphia-negative acute lymphoblastic leukemia: a GRAALL-2005 study.

Whereas the prognosis of adult patients with Philadelphia-negative acute lymphoblastic leukemia (ALL) has greatly improved since the advent of pediatric-inspired regimens, the impact of initial central nervous system (CNS) involvement has not been formerly re-evaluated. We report here the outcome of patients with initial CNS involvement included in the pediatric-inspired prospective randomized GRAALL-2005 study. Between 2006 and 2014, 784 adult patients (aged 18-59 years) with newly diagnosed Philadelphia-negative ALL were included, of whom 55 (7%) had CNS involvement. In CNSpositive patients, overall survival was shorter (median 1.9 years vs. not reached, HR=1.8 [1.3-2.6], P<0.001). While there was no statistical difference in cumulative incidence of relapse between CNS+ and CNS- patients (HR=1.5 [0.9-2.5], P=0.11), non-relapse mortality was significantly higher in those with initial CNS disease (HR=2.1 [1.2-3.5], P=0.01). This increase in toxicity was mostly observed in patients randomized to the high-dose cyclophosphamide arm and in those who received allogeneic stem cell transplantation. Exploratory landmark analyses did not show any association between either cranial irradiation or allogeneic stem cell transplantation and outcome. Despite improved outcome in young adult ALL patients with pediatric-inspired protocols, CNS involvement is associated with a worse outcome mainly due to excess toxicity, without improved outcome with allogeneic SCT.

Ruxolitinib-induced reactivation of cytomegalovirus and Epstein-Barr virus in graft-versus-host disease.

OBJECTIVES: Steroid-refractory graft-versus-host disease (SR-GVHD) is a challenging complication of allogeneic hematopoietic stem cell transplantation, and leads to high morbidity and mortality rates. The orally administered, selective Janus-associated kinase 1/2 inhibitor ruxolitinib gives overall response rates (ORR) of more than 70 % in acute and chronic SR-GVHD. However, several studies have highlighted an elevated risk of cytomegalovirus (CMV) reactivation in patients with ruxolitinib-treated SR-GVHD. METHODS: We therefore analyzed risk of CMV and Epstein-Barr virus (EBV) primary infection or reactivation in 57 patients with ruxolitinib-treated GVHD, while taking account of the competing risk (CR) of death prior to the first reactivation. RESULTS: Initiation of ruxolitinib treatment was a significant adverse prognostic factor for the CR of first CMV reactivation (hazard ratio (HR)= 1.747, 95 % confidence interval (CI): 1.33-2.92, p < 0.0001) and first EBV reactivation (HR=2.657, 95 % CI: 1.82-3.87, p < 0.0001) during GVHD. In our cohort of ruxolitinib-treated patients, the ORR (48 % and 58 % for acute and chronic GVHD, respectively) and the toxicity profile (haematological adverse events in 29.8 % of the patients) were similar to the literature values. CONCLUSION: Given ruxolitinib's efficacy in SR-GVHD, use of this drug should not be limited by the fear of viral reactivation; however, our present results emphasize the importance of monitoring the viral load.

A real-world comparison of tisagenlecleucel and axicabtagene ciloleucel CAR T cells in relapsed or refractory diffuse large B cell lymphoma.

Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) have both demonstrated impressive clinical activity in relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL). In this study, we analyzed the outcome of 809 patients with R/R DLBCL after two or more previous lines of treatment who had a commercial chimeric antigen receptor (CAR) T cells order for axi-cel or tisa-cel and were registered in the retrospective French DESCAR-T registry study ( NCT04328298 ). After 1:1 propensity score matching (n = 418), the best overall response rate/complete response rate (ORR/CRR) was 80%/60% versus 66%/42% for patients treated with axi-cel compared to tisa-cel, respectively (P < 0.001 for both ORR and CRR comparisons). After a median follow-up of 11.7 months, the 1-year progression-free survival was 46.6% for axi-cel and 33.2% for tisa-cel (hazard ratio (HR) = 0.61; 95% confidence interval (CI), 0.46-0.79; P = 0.0003). Overall survival (OS) was also significantly improved after axi-cel infusion compared to after tisa-cel infusion (1-year OS 63.5% versus 48.8%; HR = 0.63; 95% CI, 0.45-0.88; P = 0.0072). Similar findings were observed using the inverse probability of treatment weighting statistical approach. Grade 1-2 cytokine release syndrome was significantly more frequent with axi-cel than with tisa-cel, but no significant difference was observed for grade ≥3. Regarding immune effector cell-associated neurotoxicity syndrome (ICANS), both grade 1-2 and grade ≥3 ICANS were significantly more frequent with axi-cel than with tisa-cel. In conclusion, our matched comparison study supports a higher efficacy and also a higher toxicity of axi-cel compared to tisa-cel in the third or more treatment line for R/R DLBCL.

Outcomes of patients with aggressive B-cell lymphoma after failure of anti-CD19 CAR T-cell therapy: a DESCAR-T analysis.

Anti-CD19 chimeric antigen receptor (CAR) T-cells represent a major advance in the treatment of relapsed/refractory aggressive B-cell lymphomas. However, a significant number of patients experience failure. Among 550 patients registered in the French registry DESCAR-T, 238 (43.3%) experienced progression/relapse, with a median follow-up of 7.9 months. At registration, 57.0% of patients presented an age-adjusted International Prognostic Index of 2 to 3, 18.9% had Eastern Cooperative Oncology Group performance status ≥2, 57.1% received >3 lines of treatment prior to receiving CAR T-cells, and 87.8% received bridging therapy. At infusion, 66% of patients presented progressive disease, and 38.9% had high lactate dehydrogenase (LDH). Failure after CAR T-cell treatment occurred after a median of 2.7 months (range: 0.2-21.5). Fifty-four patients (22.7%) presented very early failure (day [D] 0-D30); 102 (42.9%) had early failure (D31-D90), and 82 (34.5%) had late (>D90) failure. After failure, 154 patients (64%) received salvage treatment: 38.3% received lenalidomide, 7.1% bispecific antibodies, 21.4% targeted treatment, 11% radiotherapy, and 20% immunochemotherapy with various regimens. Median progression-free survival was 2.8 months, and median overall survival (OS) was 5.2 months. Median OS for patients failing during D0-D30 vs after D30 was 1.7 vs 3.0 months, respectively (P = .0001). Overall, 47.9% of patients were alive at 6 months, but only 18.9% were alive after very early failure. In multivariate analysis, predictors of OS were high LDH at infusion, time to CAR-T failure

A phase 1b study of glasdegib + azacitidine in patients with untreated acute myeloid leukemia and higher-risk myelodysplastic syndromes.

This phase 1b study evaluated glasdegib (100 mg once daily) + azacitidine in adults with newly diagnosed acute myeloid leukemia (AML), higher-risk myelodysplastic syndromes (MDS), or chronic myelomonocytic leukemia (CMML) who were ineligible for intensive chemotherapy. Of 72 patients enrolled, 12 were in a lead-in safety cohort (LIC) and 60 were in the AML and MDS (including CMML) expansion cohorts. In the LIC, the safety profile of glasdegib + azacitidine was determined to be consistent with those of glasdegib or azacitidine alone, with no evidence of drug-drug interaction. In the expansion cohort, the most frequently (≥ 10%) reported non-hematologic Grade ≥ 3 treatment-emergent adverse events were decreased appetite, electrocardiogram QT prolongation, and hypertension in the AML cohort and sepsis, diarrhea, hypotension, pneumonia, and hyperglycemia in the MDS cohort. Overall response rates in the AML and MDS cohorts were 30.0% and 33.3%, respectively; 47.4% and 46.7% of patients who were transfusion dependent at baseline achieved independence. Median overall survival (95% confidence interval) was 9.2 (6.2-14.0) months and 15.8 (9.3-21.9) months, respectively, and response was associated with molecular mutation clearance. Glasdegib + azacitidine in patients with newly diagnosed AML or MDS demonstrated an acceptable safety profile and preliminary evidence of clinical benefits.Trial registration: ClinicalTrials.gov NCT02367456.

Effective Letermovir Prophylaxis of CMV infection post allogeneic hematopoietic cell transplantation: Results from the French temporary authorization of use compassionate program.

We report the results of the French Temporary Authorization of Use (ATU) compassionate program of letermovir for primary prophylaxis conducted in 21 transplant centers. Patients were CMV seropositive allogeneic hematopoietic cell transplantation recipients and at high risk for CMV infection. Primary prophylaxis was defined as initiation of letermovir between day 0 and day +28 post-transplant. Between November 2017 and January 2019, 96 patients with a median age of 56 years received letermovir and follow-up data were available for 78 patients. The median time from transplant to letermovir initiation was 4 days, and the median duration of exposure to letermovir was 78 days, with 57 patients still on treatment at the cutoff date. Letermovir was temporarily discontinued in 4 patients (5.1%) and stopped in 39 patients (50.0%), in most cases due to planned end of treatment (n = 16, 20.5%). Fifteen patients (19.2%) each presented one positive CMV PCR, in median 13 days after letermovir initiation. Clinically significant CMV infection was reported in 5 patients (6.4%). No CMV disease was reported. At least one adverse drug reaction was reported for 12 patients (15.4%). In this early access program, letermovir was effective with comparable results of the phase 3 study with a low rate of clinically significant CMV infection, including in patients who were at high-risk for CMV infection.

Real-life experience with CPX-351 and impact on the outcome of high-risk AML patients: a multicentric French cohort.

CPX-351 is a liposomal formulation of cytarabine and daunorubicin approved for the treatment of adults with newly diagnosed, therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (MRC-AML). We retrospectively analyzed the efficacy and safety of CPX-351 in a real-world setting in 103 patients from 12 French centers, including the evaluation of molecular abnormalities at baseline and minimal residual disease (MRD) in responding patients, compared with a historical data set from Bordeaux-Toulouse DATAML registry. A favorable safety profile was observed, with a low frequency of alopecia (11%) and gastrointestinal toxicity (50%). The overall response rate after induction was 59%, and MRD <10-3 was achieved in 57% of complete response (CR)/CR with incomplete hematological recovery (CRi) patients. Only the presence of mutated TP53 (P = .02) or PTPN11 (P = .004) predicted lower response in multivariate analysis. Interestingly, high-risk molecular prognosis subgroups defined by 2017 European LeukemiaNet risk stratification, including ASXL1 and RUNX1 mutations, were not associated with a significantly lower response rate using CPX-351. With a median follow-up of 8.6 months, median overall survival (OS) was 16.1 months. Thirty-six patients underwent allogeneic stem cell transplantation with a significantly longer median OS compared with nontransplanted patients (P < .001). In multivariate analyses, only spliceosome mutations were associated with better OS (P = .04). In comparison with intensive chemotherapy, there was no difference in OS for patients <60 years. These data confirm the efficacy and safety of CPX-351 in high-risk AML (t-AML and MRC-AML) in a real-life setting. CPX-351 is a treatment of choice for patients aged ≥60 years.

Doppler Echocardiographic Indices Are Specific But Not Sensitive to Predict Pulmonary Artery Occlusion Pressure in Critically Ill Patients Under Mechanical Ventilation.

OBJECTIVES: The objective of this study was to prospectively evaluate the ability of transthoracic echocardiography to assess pulmonary artery occlusion pressure in mechanically ventilated critically ill patients. DESIGN: In a prospective observational study. SETTING: Amiens University Hospital Medical ICU. PATIENTS: Fifty-three mechanically ventilated patients in sinus rhythm admitted to our ICU. INTERVENTION: Transthoracic echocardiography was performed simultaneously to pulmonary artery catheter. MEASUREMENTS AND MAIN RESULTS: Transmitral early velocity wave recorded using pulsed wave Doppler (E), late transmitral velocity wave recorded using pulsed wave Doppler (A), and deceleration time of E wave were recorded using pulsed Doppler as well as early mitral annulus velocity wave recorded using tissue Doppler imaging (E'). Pulmonary artery occlusion pressure was measured simultaneously using pulmonary artery catheter. There was a significant correlation between pulmonary artery occlusion pressure and lateral ratio between E wave and E' (E/E' ratio) (r = 0.35; p < 0.01), ratio between E wave and A wave (E/A ratio) (r = 0.41; p < 0.002), and deceleration time of E wave (r = -0.34; p < 0.02). E/E' greater than 15 was predictive of pulmonary artery occlusion pressure greater than or equal to 18 mm Hg with a sensitivity of 25% and a specificity of 95%, whereas E/E' less than 7 was predictive of pulmonary artery occlusion pressure less than 18 mm Hg with a sensitivity of 32% and a specificity of 81%. E/A greater than 1.8 yielded a sensitivity of 44% and a specificity of 95% to predict pulmonary artery occlusion pressure greater than or equal to 18 mm Hg, whereas E/A less than 0.7 was predictive of pulmonary artery occlusion pressure less than 18 mm Hg with a sensitivity of 19% and a specificity of 94%. A similar predictive capacity was observed when the analysis was confined to patients with EF less than 50%. A large proportion of E/E' measurements 32 (60%) were situated between the two cut-off values obtained by the receiver operating characteristic curves: E/E' greater than 15 and E/E' less than 7. CONCLUSIONS: In mechanically ventilated critically ill patients, Doppler transthoracic echocardiography indices are highly specific but not sensitive to estimate pulmonary artery occlusion pressure.

A one-step assay for sorted CD3+ cell purity and chimerism after hematopoietic stem cell transplantation.

A hematopoietic chimerism assay is the laboratory test for monitoring engraftment and quantifying the proportions of donor and recipient cells after hematopoietic stem cell transplantation recipients. Flow cytometry is the reference method for determining the purity of CD3+ cells on the chimerism of selected CD3+ cells. In the present study, we developed a single-step procedure that combines the CD3+ purity assay (using the PCR-based Non-T Genomic Detection Kit from Accumol, Calgary, Canada) and the qPCR chimerism monitoring assay (the QTRACE qPCR assay from Jeta Molecular, Utrecht, the Netherlands). First, for the CD3+ purity assay, we used a PCR-friendly protocol by changing the composition of the ready-to-use reaction tubes (buffer and taq polymerase) and obtained a satisfactory calibration plot (R2 = 0.8924) with a DNA reference scale of 2 ng/µl. Next, 29 samples (before and after CD3 positive selection) were analyzed, the mean cell purity was, respectively, 19.6% ± 6.45 and 98.9% ± 1.07 in the flow cytometry assay; 26.8% ± 7.63 and 98.5% ± 1.79 in the PCR-based non-T genomic detection assay. Our results showed that the CD3+ purity assay using a qPCR kit is a robust alternative to the flow cytometry assay and is associated with time savings when combined with a qPCR chimerism assay.

The lenalidomide/bortezomib/dexamethasone regimen for the treatment of blastic plasmacytoid dendritic cell neoplasm.

We describe the use and value of a lenalidomide/bortezomib/dexamethasone regimen for the treatment of three patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN, a disease that lacks a consensus treatment). After five cycles of chemotherapy, we observed two complete responses and one clinical remission. Together with the encouraging literature data on the effects of lenalidomide and bortezomib on BPDCN cells, our results might prompt further investigations of this regimen's value in BPDCN.

Transthoracic echocardiography: an accurate and precise method for estimating cardiac output in the critically ill patient.

BACKGROUND: Cardiac output (CO) monitoring is a valuable tool for the diagnosis and management of critically ill patients. In the critical care setting, few studies have evaluated the level of agreement between CO estimated by transthoracic echocardiography (CO-TTE) and that measured by the reference method, pulmonary artery catheter (CO-PAC). The objective of the present study was to evaluate the precision and accuracy of CO-TTE relative to CO-PAC and the ability of transthoracic echocardiography to track variations in CO, in critically ill mechanically ventilated patients. METHODS: Thirty-eight mechanically ventilated patients fitted with a PAC were included in a prospective observational study performed in a 16-bed university hospital ICU. CO-PAC was measured via intermittent thermodilution. Simultaneously, a second investigator used standard-view TTE to estimate CO-TTE as the product of stroke volume and the heart rate obtained during the measurement of the subaortic velocity time integral. RESULTS: Sixty-four pairs of CO-PAC and CO-TTE measurements were compared. The two measurements were significantly correlated (r = 0.95; p < 0.0001). The median bias was 0.2 L/min, the limits of agreement (LOAs) were -1.3 and 1.8 L/min, and the percentage error was 25%. The precision was 8% for CO-PAC and 9% for CO-TTE. Twenty-six pairs of ΔCO measurements were compared. There was a significant correlation between ΔCO-PAC and ΔCO-TTE (r = 0.92; p < 0.0001). The median bias was -0.1 L/min and the LOAs were -1.3 and +1.2 L/min. With a 15% exclusion zone, the four-quadrant plot had a concordance rate of 94%. With a 0.5 L/min exclusion zone, the polar plot had a mean polar angle of 1.0° and a percentage error LOAs of -26.8 to 28.8°. The concordance rate was 100% between 30 and -30°. When using CO-TTE to detect an increase in ΔCO-PAC of more than 10%, the area under the receiving operating characteristic curve (95% CI) was 0.82 (0.62-0.94) (p < 0.001). A ΔCO-TTE of more than 8% yielded a sensitivity of 88% and specificity of 66% for detecting a ΔCO-PAC of more than 10%. CONCLUSION: In critically ill mechanically ventilated patients, CO-TTE is an accurate and precise method for estimating CO. Furthermore, CO-TTE can accurately track variations in CO.