Transfemoral tricuspid valve replacement and one-year outcomes: the TRISCEND study.

BACKGROUND AND AIMS: For patients with symptomatic, severe tricuspid regurgitation (TR), early results of transcatheter tricuspid valve (TV) intervention studies have shown significant improvements in functional status and quality of life associated with right-heart reverse remodelling. Longer-term follow-up is needed to confirm sustained improvements in these outcomes. METHODS: The prospective, single-arm, multicentre TRISCEND study enrolled 176 patients to evaluate the safety and performance of transcatheter TV replacement in patients with ≥moderate, symptomatic TR despite medical therapy. Major adverse events, reduction in TR grade and haemodynamic outcomes by echocardiography, and clinical, functional, and quality-of-life parameters are reported to one year. RESULTS: Enrolled patients were 71.0% female, mean age 78.7 years, 88.0% ≥ severe TR, and 75.4% New York Heart Association classes III-IV. Tricuspid regurgitation was reduced to ≤mild in 97.6% (P < .001), with increases in stroke volume (10.5 ± 16.8 mL, P < .001) and cardiac output (0.6 ± 1.2 L/min, P < .001). New York Heart Association class I or II was achieved in 93.3% (P < .001), Kansas City Cardiomyopathy Questionnaire score increased by 25.7 points (P < .001), and six-minute walk distance increased by 56.2 m (P < .001). All-cause mortality was 9.1%, and 10.2% of patients were hospitalized for heart failure. CONCLUSIONS: In an elderly, highly comorbid population with ≥moderate TR, patients receiving transfemoral EVOQUE transcatheter TV replacement had sustained TR reduction, significant increases in stroke volume and cardiac output, and high survival and low hospitalization rates with improved clinical, functional, and quality-of-life outcomes to one year. Funded by Edwards Lifesciences, TRISCEND ClinicalTrials.gov number, NCT04221490.

Sustained Apnea for Epicardial Access With Right Ventriculography: The SAFER Epicardial Approach.

BACKGROUND: Epicardial access (EA) has emerged as an increasingly important approach for the treatment of ventricular arrhythmias and to perform other interventional cardiology procedures. EA is frequently underutilized because the current approach is challenging and carries a high risk of life-threatening complications. OBJECTIVE: The purpose of this study was to determine the efficacy and safety of the SAFER (Sustained Apnea for Epicardial Access With Right Ventriculography) epicardial approach. METHODS: Consecutive patients who underwent EA with the SAFER technique were included in this multicenter study. The primary efficacy outcome was the successful achievement of EA. The primary safety outcomes included right ventricular (RV) perforation, major hemorrhagic pericardial effusion (HPE), and bleeding requiring surgical intervention. Secondary outcomes included procedural characteristics and any complications. Our results were compared with those from previous studies describing other EA techniques to assess differences in outcomes. RESULTS: A total of 105 patients undergoing EA with the SAFER approach from June 2021 to February 2023 were included. EA was used for ventricular tachycardia ablation in 98 patients (93.4%), left atrial appendage closure in 6 patients (5.7%), and phrenic nerve displacement in 1 patient (0.9%). EA was successful in all subjects (100%). The median time to EA was 7 minutes (IQR: 5-14 minutes). No cases of RV perforation, HPE, or need of surgical intervention were observed in this cohort. Comparing our results with previous studies about EA, the SAFER epicardial approach resulted in a significant reduction in major pericardial bleeding. CONCLUSIONS: The SAFER epicardial approach is a simple, efficient, effective, and low-cost technique easily reproducible across multiple centers. It is associated with lower complication rates than previously reported techniques for EA.

Real-Time Multiplanar Reconstruction Imaging Using 3-Dimensional Transesophageal Echocardiography in Structural Heart Interventions.

The complexity of structural heart interventions has led to a demand for sophisticated periprocedural imaging guidance. Although traditional 2-dimensional (2D) transesophageal techniques are used widely, new-generation 3D ultrasound probes enable high temporal and spatial resolution. Multiplanar reconstruction of acquired 3D datasets has gained considerable momentum for precise imaging and to increase the validity of measurements. Previously, this technique was used after the acquisition of suitable 3D datasets. Recent advances in technology have enabled the use of live mode for multiplanar reconstruction across different ultrasound vendor platforms. The use of live multiplanar reconstruction can enhance the precision in real-time imaging, enable simultaneous visualization of structures of interest in multiple planes, reduce the need for probe manipulation, and thereby contribute to the success of the procedures. In this narrative review, the authors describe the rationale and utility for 3D transesophageal live multiplanar reconstruction, and outline its use for the structural heart interventions of mitral and tricuspid valve edge-to-edge repair, left atrial appendage occlusion, and the Lampoon procedure. A 3D transesophageal echocardiogram with live-multiplanar reconstruction has the potential to advance guidance of these complex interventions.

Association Between Peripheral Versus Central Access for Alternative Access Transcatheter Aortic Valve Replacement and Mortality and Stroke: A Report From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.

BACKGROUND: In some patients, the alternative access route for transcatheter aortic valve replacement (TAVR) is utilized because the conventional transfemoral approach is not felt to be either feasible or optimal. However, accurate prognostication of patient risks is not well established. This study examines the associations between peripheral (transsubclavian/transaxillary, and transcarotid) versus central access (transapical and transaortic) in alternative access TAVR and 30-day and 1-year end points of mortality and stroke for all valve platforms. METHODS: Using data from The Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry with linkage to Medicare claims, patients who underwent alternative access TAVR from June 1, 2015 to June 30, 2018 were identified. Adjusted and unadjusted Cox proportional hazards modeling were performed to determine the association between alternate access TAVR site and 30-day and 1-year end points of mortality and stroke. RESULTS: Of 7187 alternative access TAVR patients, 3725 (52%) had peripheral access and 3462 (48%) had central access. All-cause mortality was significantly lower in peripheral access versus central access group at in-hospital and 1 year (2.9% versus 6.3% and 20.3% versus 26.6%, respectively), but stroke rates were higher (5.0% versus 2.8% and 7.3% versus 5.5%, respectively; all P<0.001). These results persisted after 1-year adjustment (death adjusted hazard ratio, 0.72 [95% CI, 0.62-0.85] and stroke adjusted hazard ratio, 2.92 [95% CI, 2.21-3.85]). When broken down by individual subtypes, compared with transaxillary/subclavian access patients, transapical, and transaortic access patients had higher all-cause mortality but less stroke (P<0.05). CONCLUSIONS: In this real-world, contemporary, nationally representative benchmarking study of alternate access TAVR sites, peripheral access was associated with favorable mortality and morbidity outcomes compared with central access, at the expense of higher stroke. These findings may allow for accurate prognostication of risk for patient counseling and decision-making for the heart team with regard to alternative access TAVR.

Mitral Valve Annuloplasty Failure and Percutaneous Treatment Options.

PURPOSE OF REVIEW: Mitral valve repair is a common surgical procedure for both primary and secondary mitral regurgitation. With operations performed earlier in disease progression and increased patient longevity, the need for a repeat intervention is not infrequent. With the associated risks of reoperation and patient comorbidities, percutaneous techniques for acute or delayed failure after ring annuloplasty are emerging. RECENT FINDINGS: Current commercially available devices, used in "off-label" ways, such as the MitraClip, may be effective in repairing recurrent mitral regurgitation after annuloplasty. Similarly, a valve-in-ring transcatheter mitral valve replacement can be considered in patients at high risk for surgical reoperation. These procedures are not without risk, for example, resultant mitral stenosis in the setting of edge-to-edge repair or left ventricular outflow tract (LVOT) obstruction with valve-in-ring transcatheter mitral valve replacement. Newer devices are emerging to permit more options for this subset of patients, which include transcatheter valves that are specifically designed for the mitral position. Undoubtedly, surgical reoperation has increased risk as compared to primary operation. Though percutaneous options are evolving, use in this patient population is currently limited to "off-label" use and is also associated with procedural complexities and risk. It is prudent for cardiologists, surgeons, and anesthesiologists to weigh risks, benefits, and limitations when considering patients for surgical reoperation, percutaneous repair, or transcatheter replacement after failed mitral annuloplasty.

Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room: A Surgery-Based Approach: From the American Society of Echocardiography in Collaboration with the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons.

Intraoperative transesophageal echocardiography is a standard diagnostic and monitoring tool employed in the management of patients undergoing an entire spectrum of cardiac surgical procedures, ranging from "routine" surgical coronary revascularization to complex valve repair, combined procedures, and organ transplantation. Utilizing a protocol as a starting point for imaging in all procedures and all patients enables standardization of image acquisition, reduction in variability in quality of imaging and reporting, and ultimately better patient care. Clear communication of the echocardiographic findings to the surgical team, as well as understanding the impact of new findings on the surgical plan, are paramount. Equally important is the need for complete understanding of the technical steps of the surgical procedures being performed and the complications that may occur, in order to direct the postprocedure evaluation toward aspects directly related to the surgical procedure and to provide pertinent echocardiographic information. The rationale for this document is to outline a systematic approach describing how to apply the existing guidelines to questions on cardiac structure and function specific to the intraoperative environment in open, minimally invasive, or hybrid cardiac surgery procedures.

Relationship Between Hospital Surgical Aortic Valve Replacement Volume and Transcatheter Aortic Valve Replacement Outcomes.

OBJECTIVES: The aim of this study was to examine whether hospital surgical aortic valve replacement (SAVR) volume was associated with corresponding transcatheter aortic valve replacement (TAVR) outcomes. BACKGROUND: Recent studies have demonstrated a volume-outcome relationship for TAVR. METHODS: In total, 208,400 fee-for-service Medicare beneficiaries were analyzed for all aortic valve replacement procedures from 2012 to 2015. Claims for patients <65 years of age, concomitant coronary artery bypass grafting surgery, other heart valve procedures, or other major open heart procedures were excluded, as were secondary admissions for aortic valve replacement. Hospital SAVR volumes were stratified on the basis of mean annual SAVR procedures during the study period. The primary outcomes were 30-day and 1-year post-operative TAVR survival. Adjusted survival following TAVR was assessed using multivariate Cox regression. RESULTS: A total of 65,757 SAVR and 42,967 TAVR admissions were evaluated. Among TAVR procedures, 21.7% (n = 9,324) were performed at hospitals with <100 (group 1), 35.6% (n = 15,298) at centers with 100 to 199 (group 2), 22.9% (n = 9,828) at centers with 200 to 299 (group 3), and 19.8% (n = 8,517) at hospitals with ≥300 SAVR cases/year (group 4). Compared with group 4, 30-day TAVR mortality risk-adjusted odds ratios were 1.32 (95% confidence interval: 1.18 to 1.47) for group 1, 1.25 (95% confidence interval: 1.12 to 1.39) for group 2, and 1.08 (95% confidence interval: 0.82 to 1.25) for group 3. These adjusted survival differences in TAVR outcomes persisted at 1 year post-procedure. CONCLUSIONS: Total hospital SAVR volume appears to be correlated with TAVR outcomes, with higher 30-day and 1-year mortality observed at low-volume centers. These data support the importance of a viable surgical program within the heart team, and the use of minimum SAVR hospital thresholds may be considered as an additional metric for TAVR performance.

Comparison of Sex-Based Differences in Home or Nonhome Discharge Utilization of Rehabilitative Services and Outcomes Following Transcatheter Aortic Valve Implantation in the United States.

Sex-based differences in outcomes have been shown to affect caregiving in medical disciplines. Increased spending due to postacute care transfer policies has led hospitals to further scrutinize patient outcomes and disposition patterns after inpatient admissions. We examined sex-based differences in rehabilitative service utilization after transcatheter aortic valve implantation (TAVI). We queried all TAVI discharges in the National Inpatient Sample database from 2012 to 2014 (n = 40,900). Thirteen thousand eight hundred fifteen patients were discharged to home and 12,175 patients were discharged to rehabilitation facility; those not discharged routinely or to a rehabilitation facility were excluded. Patients with nonhome discharges were older (83.3 vs 79.0 years) and female (58.3% vs 37.7%) with a greater number of chronic conditions (9.91 vs 9.03) and number of Elixhauser co-morbidities (6.5 vs 5.8, all p < 0.05). Nonhome discharge patients also had a significantly longer length of stay (LOS) (11.3 days vs 5.3 days) and higher hospitalization costs ($66,246 vs $48,710, all p < 0.001) compared to home-discharged patients. Overall in-hospital mortality for female patients who underwent TAVI was higher compared to males (4.6% vs 3.6%, p < 0.05). On multivariable logistic regression, female sex was an independent predictor for disposition to rehabilitation facilities after TAVI (odds ratio 2.17; 95% confidence interval: 1.88 to 2.50; p < 0.001). Other independent predictors for females discharged to rehabilitation included the presence of rheumatoid arthritis and collagen vascular disease, body mass index greater than 30 kg/m2, depression, and sum of Elixhauser co-morbidities (all p < 0.001). In conclusion, nonhome discharge TAVI patients added LOS and hospital costs compared to home discharge TAVI patients, and female sex was one of the major predictors despite the lower co-morbidities.

Comparison of Navigator Triggering Reduced Field of View and Large Field of View Diffusion-Weighted Imaging of the Pancreas.

RATIONALE AND OBJECTIVES: The purpose of this study is to compare image quality, presence and grade of artifacts, signal-to-noise ratio, and apparent diffusion coefficient (ADC) values in pancreatic tissue between high-resolution navigator-triggered (NT) restricted field of view (rFOV) FOCUS single-shot (SS) echo-planar imaging (EPI) diffusion-weighted imaging (DWI) and NT large FOV SS-EPI DWI. MATERIALS AND METHODS: Magnetic resonance imaging examinations were performed with GE 3-T systems using a 32-channel body array coil. Seventeen consecutive patients were imaged. A 5-point scale semiquantitative grading system was used to evaluate image quality and general artifacts. Signal-to-noise ratio and ADC were measured in the head, body, and tail of the pancreas. Statistical analysis was performed using Student t test and Wilcoxon signed rank test, with differences considered significant for P value less than 0.05. RESULTS: More artifacts were present on large FOV compared with rFOV FOCUS SS-EPI DW images (P < 0.01). Restricted field of view image quality was subjectively better (P < 0.01). No difference in the signal-to-noise ratio was demonstrated between the 2 image datasets. Apparent diffusion coefficient values were significantly lower (P < 0.01) when calculated from rFOV images than large FOV images. CONCLUSIONS: Our results demonstrate better image quality and reduced artifacts in rFOV images compared with large FOV DWI. Measurements from ADC maps derived from rFOV DWI show significantly lower ADC values when compared with ADC maps derived from large FOV DWI.

Percutaneous Techniques, Limitations and Challenges for the Failed Surgical Mitral Intervention.

The advent of percutaneous therapies has significantly altered therapeutic options for patients with valvular heart disease. Building on the success of transcatheter aortic valve replacement, both expanded indications and purpose-built devices are now being used to address percutaneous approaches for mitral valve pathology. While surgical mitral valve repair remains the gold standard for addressing significant mitral valve pathology, there has been a progressive increase in the utilization of bioprosthetic valves despite their limited lifespan. The risks of reoperation to address mitral valve repair failure or bioprosthetic valve dysfunction is not insignificant. In light of the aging population and the potential for significant associated comorbidities, less invasive alternative techniques hold particular appeal. Utilization of commercially available transcatheter aortic valve replacement valves for failed surgical valves has been shown to have better short-term mortality than would be predicted for open reoperation. As a result, the US Food and Drug Administration approved the utilization of transcatheter mitral valve-in-valve replacement for the failed bioprosthetic valve in high surgical risk patients. Despite the favorable outcomes, transcatheter mitral valve-in-valve is not without procedural challenges and potential complications including malpositioning, embolization, paravalvular leak, and outflow tract obstruction. Awareness of these challenges, mitigation strategies, and therapeutic options is imperative to optimizing outcomes in this high-risk patient population.

Clinical Significance of Greater Implantation Height with SAPIEN 3 Transcatheter Heart Valve.

BACKGROUND: A lower rate of permanent pacemaker (PPM) has been linked to a target aortic implantation height (AIH) >0.70, following transcatheter aortic valve replacement (TAVR) with the SAPIEN 3 valve. Based on clinical experience, it was hypothesized that a higher AIH (≥0.85) would lower the rate of PPM implantation. METHODS: A total of 127 patients (66 females, 61 males; mean age 82 ± 8 years) underwent TAVR with the SAPIEN 3 valve between May 2015 and July 2016. AIH was defined as the proportion of the valve frame above the aortic annulus in the post-deployment aortogram. A target AIH (≥0.70) was achieved in 113 patients (89%). Cases were stratified into a High Implantation (HI) group (AIH ≥0.85; 33 patients) or a Standard Implantation (SI) group (AIH <0.85; 94 patients). RESULTS: The mean Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score of all patients was 6.4 ± 3.5%. Preoperative right bundle branch block (RBBB) was prevalent in 13% of SI patients, and in 18% of HI patients (p = 0.56). There were no significant differences in operative mortality (3.2% versus 0%), median length of stay (2 days versus 3 days) and incidence of moderate-to-severe paravalvular leak (3.2% versus 0%; all p >0.410) between SI and HI patients, respectively. Likewise, the incidence of new PPM did not differ between the two groups (12% in HI versus 13% in SI; p ≥0.99). The mean AIH was similar for patients with PPM implantation (0.80 ± 0.08) compared to those without (0.78 ± 0.06; p = 0.520). Preoperative RBBB was significantly associated with PPM implantation (odds ratio (OR) 10.1; p = 0.002), and patients who underwent PPM implantation had a higher operative mortality (12.5% versus 1%; p = 0.040). CONCLUSIONS: Among TAVR patients who received the SAPIEN 3 heart valve, a higher AIH (≥0.85) was not associated with a lower rate of PPM implantation or increased operative mortality. Prior RBBB was the only independent risk factor for new PPM implantation. Long-term follow up is crucial in determining the clinical significance of PPM implantation.

Transcatheter Mitral Valve Repair Using the Edge-to-Edge Clip.

Percutaneous intervention for mitral valve (MV) disease has been established as an alternative to open surgical MV repair in patients with prohibitive surgical risk. Multiple percutaneous approaches have been described and are in various stages of development. Edge-to-edge leaflet plication with the MitraClip (Abbott, Menlo Park, CA) is currently the only Food and Drug Administration-approved device specifically for primary or degenerative lesions. Use of the edge-to-edge clip for secondary mitral regurgitation is currently under investigation and may result in expanded indications. Echocardiography has significantly increased our understanding of the anatomy of the MV and provided us with the ability to classify and quantify the associated mitral regurgitation. For percutaneous interventions of the MV, transesophageal echocardiography imaging is used for patient screening, intraprocedural guidance, and confirmation of the result. Optimal outcomes require the echocardiographer and the proceduralist to have a thorough understanding of intra-atrial septal and MV anatomy, as well as an appreciation for the key points and potential pitfalls of each of the procedural steps. With increasing experience, more complex valvular pathology can be successfully percutaneously treated. In addition to two-dimensional echocardiography, advances in three-dimensional echocardiography and fusion imaging will continue to support the refinement of current technologies, the expansion of clinical applications, and the development of novel devices.

Novel fast-track recovery protocol for alternative access transcatheter aortic valve replacement: application to non-femoral approaches.

OBJECTIVES: Although the transfemoral approach for transcatheter aortic valve replacement is the preferred choice, alternative access remains indicated for inadequate iliofemoral vessels. We report the successful implementation of a novel fast-track (FT) protocol for patients undergoing alternative access transcatheter aortic valve replacement compared with conventional controls. METHODS: Between September 2014 and January 2017, 31 and 23 patients underwent alternative access transcatheter aortic valve replacement under FT and pre-fast-track (p-FT) protocols, respectively. Comparisons of outcomes (in terms of mortality, complications, readmissions and resource utilization) were made before and after the implantation of the FT protocol in September 2015. RESULTS: Overall, mean age was 78.7 years in FT and 79.6 years in p-FT patients (P = 0.71). There were no significant differences in procedural (3.2% vs 13.0%, P = 0.301) or 90-day mortality (3.2% vs 17.4%, P = 0.151) between the FT and p-FT groups, respectively. Compared with p-FT patients, FT patients had significantly shorter intensive care unit stays (12 h vs 27 h, P = 0.006) and a trend towards more discharges within 3 days (41.9% vs 17.4%, P = 0.081). Resource utilization analyses projected a 56% and 17% reduction in the mean intensive care unit time (hours) per 100 patients and the total length of stay (days) per 100 patients, respectively, with respect to the FT approach. CONCLUSIONS: This pilot study demonstrates the feasibility and safety of the novel FT protocol for alternative access transcatheter aortic valve replacement, resulting in shorter intensive care unit stays, without increasing procedural complications or readmissions. With the expected increase in transcatheter aortic valve replacement utilization, FT protocols should be integrated with a multidisciplinary heart team approach to enhance patient recovery and optimize resource utilization.

Transthoracic Echocardiography to Assess Aortic Regurgitation after TAVR: A Comparison with Periprocedural Transesophageal Echocardiography.

BACKGROUND: We aimed to compare periprocedural transesophageal echocardiography (TEE) with postprocedural transthoracic echocardiography (TTE) for the diagnosis of aortic regurgitation (AR). METHODS AND RESULTS: TEE and TTE images of 163 transcatheter aortic valve replacement (TAVR) patients (mean age 81 ± 8 years; 56% men) were reviewed separately and blinded to each other as well as to all clinical data. The median time between TEE during TAVR (TEE/TAVR) and TTE was 4 days (IQR 2-10 days). After TAVR, 48% of the patients had at least trace AR by TEE, 56% by angiography and 67% by TTE. The majority of AR was paravalvular (78%). More patients were classified with mild-to-moderate AR by TTE than by TEE (44 vs. 22%, p < 0.01). When examining the 46 patients with AR by TTE which was not at TEE/TAVR, both systolic and diastolic blood pressure (SBP and DBP) were significantly higher during TTE than during TEE (mean ΔSBP = 9 ± 4 mm Hg and mean ΔDBP = 6 ± 2 mm Hg, p < 0.01 for both). No differences in BP between TEE and TTE were found among patients with no AR or among those who had AR in both studies. At a median follow-up of 185 days (IQR 39-424 days), the overall mortality was 17%, but this was not associated with the presence of AR on TTE or TEE. CONCLUSIONS: Patients' hemodynamic conditions may result in underdiagnosis of paravalvular regurgitation in periprocedural TEE. Our findings suggest that a postprocedural evaluation for AR by TTE could serve as a reasonable alternative to TEE for the evaluation of AR.

A Multicenter Pilot Study Assessing Regional Cerebral Oxygen Desaturation Frequency During Cardiopulmonary Bypass and Responsiveness to an Intervention Algorithm.

BACKGROUND: The purpose of this multicenter pilot study was to: (1) determine the frequency of regional cerebral oxygen saturation (rScO2) desaturations during cardiac surgery involving cardiopulmonary bypass (CPB); (2) evaluate the accuracy of clinician-identified rScO2 desaturations compared with those recorded continuously during surgery by the near-infrared spectroscopy (NIRS) monitor; and (3) assess the effectiveness of an intervention algorithm for reversing rScO2 desaturations. METHODS: Two hundred thirty-five patients undergoing coronary artery bypass graft and/or valvular surgery were enrolled at 8 US centers in this prospective observational study. NIRS (Invos™ 5100C; Covidien) was used to monitor rScO2 during surgery. The frequency and magnitude of rScO2 decrements >20% from preanesthesia baseline were documented, and the efficacy of a standard treatment algorithm for correcting rScO2 was determined. The data from the NIRS monitor were downloaded at the conclusion of surgery and sent to the coordinating center where the number of clinician-identified rScO2 desaturation events was compared with the number detected by the NIRS monitor. RESULTS: The average rScO2 obtained at baseline (mean ± SD, 61% ± 11%; 99% confidence interval, 57%-65%) and during CPB (62% ± 14%; 57%-67%) was not different. However, rScO2 after separation from CPB (56% ± 11%; 53%-60%) was lower than measurements at baseline and during CPB (P < 0.001). During CPB, rScO2 desaturations occurred in 61% (99% confidence interval, 50%-75%) of patients. The area under the curve for product of magnitude and duration of the rScO2 was (mean ± SD, 145.2; 384.8% × min). Clinicians identified all patients with an rScO2 desaturation but identified only 340 (89.5%) of the 380 total desaturation events. Of the 340 clinician-identified rScO2 desaturation events, 115 resolved with usual clinical care before implementation of the treatment algorithm. For the remaining 225 events, the treatment algorithm resulted in resolution of the rScO2 desaturation in all but 18 patients. CONCLUSIONS: This multicenter pilot study found that 50% to 75% of patients undergoing cardiac surgery experience one or more rScO2 desaturations during CPB. Nearly 10% of desaturation events were not identified by clinicians, suggesting that appropriate alarming systems should be adopted to alert clinicians of such events. The intervention algorithm was effective in reversing clinically identified rScO2 desaturations in the majority of events.